1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * System Control and Management Interface (SCMI) Message Protocol driver
4 *
5 * SCMI Message Protocol is used between the System Control Processor(SCP)
6 * and the Application Processors(AP). The Message Handling Unit(MHU)
7 * provides a mechanism for inter-processor communication between SCP's
8 * Cortex M3 and AP.
9 *
10 * SCP offers control and management of the core/cluster power states,
11 * various power domain DVFS including the core/cluster, certain system
12 * clocks configuration, thermal sensors and many others.
13 *
14 * Copyright (C) 2018-2024 ARM Ltd.
15 */
16
17 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
18
19 #include <linux/bitmap.h>
20 #include <linux/debugfs.h>
21 #include <linux/device.h>
22 #include <linux/export.h>
23 #include <linux/idr.h>
24 #include <linux/io.h>
25 #include <linux/io-64-nonatomic-hi-lo.h>
26 #include <linux/kernel.h>
27 #include <linux/kmod.h>
28 #include <linux/ktime.h>
29 #include <linux/hashtable.h>
30 #include <linux/list.h>
31 #include <linux/module.h>
32 #include <linux/of.h>
33 #include <linux/platform_device.h>
34 #include <linux/processor.h>
35 #include <linux/refcount.h>
36 #include <linux/slab.h>
37 #include <linux/xarray.h>
38
39 #include "common.h"
40 #include "notify.h"
41
42 #include "raw_mode.h"
43
44 #define CREATE_TRACE_POINTS
45 #include <trace/events/scmi.h>
46
47 #define SCMI_VENDOR_MODULE_ALIAS_FMT "scmi-protocol-0x%02x-%s"
48
49 static DEFINE_IDA(scmi_id);
50
51 static DEFINE_XARRAY(scmi_protocols);
52
53 /* List of all SCMI devices active in system */
54 static LIST_HEAD(scmi_list);
55 /* Protection for the entire list */
56 static DEFINE_MUTEX(scmi_list_mutex);
57 /* Track the unique id for the transfers for debug & profiling purpose */
58 static atomic_t transfer_last_id;
59
60 static struct dentry *scmi_top_dentry;
61
62 /**
63 * struct scmi_xfers_info - Structure to manage transfer information
64 *
65 * @xfer_alloc_table: Bitmap table for allocated messages.
66 * Index of this bitmap table is also used for message
67 * sequence identifier.
68 * @xfer_lock: Protection for message allocation
69 * @max_msg: Maximum number of messages that can be pending
70 * @free_xfers: A free list for available to use xfers. It is initialized with
71 * a number of xfers equal to the maximum allowed in-flight
72 * messages.
73 * @pending_xfers: An hashtable, indexed by msg_hdr.seq, used to keep all the
74 * currently in-flight messages.
75 */
76 struct scmi_xfers_info {
77 unsigned long *xfer_alloc_table;
78 spinlock_t xfer_lock;
79 int max_msg;
80 struct hlist_head free_xfers;
81 DECLARE_HASHTABLE(pending_xfers, SCMI_PENDING_XFERS_HT_ORDER_SZ);
82 };
83
84 /**
85 * struct scmi_protocol_instance - Describe an initialized protocol instance.
86 * @handle: Reference to the SCMI handle associated to this protocol instance.
87 * @proto: A reference to the protocol descriptor.
88 * @gid: A reference for per-protocol devres management.
89 * @users: A refcount to track effective users of this protocol.
90 * @priv: Reference for optional protocol private data.
91 * @version: Protocol version supported by the platform as detected at runtime.
92 * @negotiated_version: When the platform supports a newer protocol version,
93 * the agent will try to negotiate with the platform the
94 * usage of the newest version known to it, since
95 * backward compatibility is NOT automatically assured.
96 * This field is NON-zero when a successful negotiation
97 * has completed.
98 * @ph: An embedded protocol handle that will be passed down to protocol
99 * initialization code to identify this instance.
100 *
101 * Each protocol is initialized independently once for each SCMI platform in
102 * which is defined by DT and implemented by the SCMI server fw.
103 */
104 struct scmi_protocol_instance {
105 const struct scmi_handle *handle;
106 const struct scmi_protocol *proto;
107 void *gid;
108 refcount_t users;
109 void *priv;
110 unsigned int version;
111 unsigned int negotiated_version;
112 struct scmi_protocol_handle ph;
113 };
114
115 #define ph_to_pi(h) container_of(h, struct scmi_protocol_instance, ph)
116
117 /**
118 * struct scmi_debug_info - Debug common info
119 * @top_dentry: A reference to the top debugfs dentry
120 * @name: Name of this SCMI instance
121 * @type: Type of this SCMI instance
122 * @is_atomic: Flag to state if the transport of this instance is atomic
123 * @counters: An array of atomic_c's used for tracking statistics (if enabled)
124 */
125 struct scmi_debug_info {
126 struct dentry *top_dentry;
127 const char *name;
128 const char *type;
129 bool is_atomic;
130 atomic_t counters[SCMI_DEBUG_COUNTERS_LAST];
131 };
132
133 /**
134 * struct scmi_info - Structure representing a SCMI instance
135 *
136 * @id: A sequence number starting from zero identifying this instance
137 * @dev: Device pointer
138 * @desc: SoC description for this instance
139 * @version: SCMI revision information containing protocol version,
140 * implementation version and (sub-)vendor identification.
141 * @handle: Instance of SCMI handle to send to clients
142 * @tx_minfo: Universal Transmit Message management info
143 * @rx_minfo: Universal Receive Message management info
144 * @tx_idr: IDR object to map protocol id to Tx channel info pointer
145 * @rx_idr: IDR object to map protocol id to Rx channel info pointer
146 * @protocols: IDR for protocols' instance descriptors initialized for
147 * this SCMI instance: populated on protocol's first attempted
148 * usage.
149 * @protocols_mtx: A mutex to protect protocols instances initialization.
150 * @protocols_imp: List of protocols implemented, currently maximum of
151 * scmi_revision_info.num_protocols elements allocated by the
152 * base protocol
153 * @active_protocols: IDR storing device_nodes for protocols actually defined
154 * in the DT and confirmed as implemented by fw.
155 * @notify_priv: Pointer to private data structure specific to notifications.
156 * @node: List head
157 * @users: Number of users of this instance
158 * @bus_nb: A notifier to listen for device bind/unbind on the scmi bus
159 * @dev_req_nb: A notifier to listen for device request/unrequest on the scmi
160 * bus
161 * @devreq_mtx: A mutex to serialize device creation for this SCMI instance
162 * @dbg: A pointer to debugfs related data (if any)
163 * @raw: An opaque reference handle used by SCMI Raw mode.
164 */
165 struct scmi_info {
166 int id;
167 struct device *dev;
168 const struct scmi_desc *desc;
169 struct scmi_revision_info version;
170 struct scmi_handle handle;
171 struct scmi_xfers_info tx_minfo;
172 struct scmi_xfers_info rx_minfo;
173 struct idr tx_idr;
174 struct idr rx_idr;
175 struct idr protocols;
176 /* Ensure mutual exclusive access to protocols instance array */
177 struct mutex protocols_mtx;
178 u8 *protocols_imp;
179 struct idr active_protocols;
180 void *notify_priv;
181 struct list_head node;
182 int users;
183 struct notifier_block bus_nb;
184 struct notifier_block dev_req_nb;
185 /* Serialize device creation process for this instance */
186 struct mutex devreq_mtx;
187 struct scmi_debug_info *dbg;
188 void *raw;
189 };
190
191 #define handle_to_scmi_info(h) container_of(h, struct scmi_info, handle)
192 #define bus_nb_to_scmi_info(nb) container_of(nb, struct scmi_info, bus_nb)
193 #define req_nb_to_scmi_info(nb) container_of(nb, struct scmi_info, dev_req_nb)
194
195 static void scmi_rx_callback(struct scmi_chan_info *cinfo,
196 u32 msg_hdr, void *priv);
197 static void scmi_bad_message_trace(struct scmi_chan_info *cinfo,
198 u32 msg_hdr, enum scmi_bad_msg err);
199
200 static struct scmi_transport_core_operations scmi_trans_core_ops = {
201 .bad_message_trace = scmi_bad_message_trace,
202 .rx_callback = scmi_rx_callback,
203 };
204
205 static unsigned long
scmi_vendor_protocol_signature(unsigned int protocol_id,char * vendor_id,char * sub_vendor_id,u32 impl_ver)206 scmi_vendor_protocol_signature(unsigned int protocol_id, char *vendor_id,
207 char *sub_vendor_id, u32 impl_ver)
208 {
209 char *signature, *p;
210 unsigned long hash = 0;
211
212 /* vendor_id/sub_vendor_id guaranteed <= SCMI_SHORT_NAME_MAX_SIZE */
213 signature = kasprintf(GFP_KERNEL, "%02X|%s|%s|0x%08X", protocol_id,
214 vendor_id ?: "", sub_vendor_id ?: "", impl_ver);
215 if (!signature)
216 return 0;
217
218 p = signature;
219 while (*p)
220 hash = partial_name_hash(tolower(*p++), hash);
221 hash = end_name_hash(hash);
222
223 kfree(signature);
224
225 return hash;
226 }
227
228 static unsigned long
scmi_protocol_key_calculate(int protocol_id,char * vendor_id,char * sub_vendor_id,u32 impl_ver)229 scmi_protocol_key_calculate(int protocol_id, char *vendor_id,
230 char *sub_vendor_id, u32 impl_ver)
231 {
232 if (protocol_id < SCMI_PROTOCOL_VENDOR_BASE)
233 return protocol_id;
234 else
235 return scmi_vendor_protocol_signature(protocol_id, vendor_id,
236 sub_vendor_id, impl_ver);
237 }
238
239 static const struct scmi_protocol *
__scmi_vendor_protocol_lookup(int protocol_id,char * vendor_id,char * sub_vendor_id,u32 impl_ver)240 __scmi_vendor_protocol_lookup(int protocol_id, char *vendor_id,
241 char *sub_vendor_id, u32 impl_ver)
242 {
243 unsigned long key;
244 struct scmi_protocol *proto = NULL;
245
246 key = scmi_protocol_key_calculate(protocol_id, vendor_id,
247 sub_vendor_id, impl_ver);
248 if (key)
249 proto = xa_load(&scmi_protocols, key);
250
251 return proto;
252 }
253
254 static const struct scmi_protocol *
scmi_vendor_protocol_lookup(int protocol_id,char * vendor_id,char * sub_vendor_id,u32 impl_ver)255 scmi_vendor_protocol_lookup(int protocol_id, char *vendor_id,
256 char *sub_vendor_id, u32 impl_ver)
257 {
258 const struct scmi_protocol *proto = NULL;
259
260 /* Searching for closest match ...*/
261 proto = __scmi_vendor_protocol_lookup(protocol_id, vendor_id,
262 sub_vendor_id, impl_ver);
263 if (proto)
264 return proto;
265
266 /* Any match just on vendor/sub_vendor ? */
267 if (impl_ver) {
268 proto = __scmi_vendor_protocol_lookup(protocol_id, vendor_id,
269 sub_vendor_id, 0);
270 if (proto)
271 return proto;
272 }
273
274 /* Any match just on the vendor ? */
275 if (sub_vendor_id)
276 proto = __scmi_vendor_protocol_lookup(protocol_id, vendor_id,
277 NULL, 0);
278 return proto;
279 }
280
281 static const struct scmi_protocol *
scmi_vendor_protocol_get(int protocol_id,struct scmi_revision_info * version)282 scmi_vendor_protocol_get(int protocol_id, struct scmi_revision_info *version)
283 {
284 const struct scmi_protocol *proto;
285
286 proto = scmi_vendor_protocol_lookup(protocol_id, version->vendor_id,
287 version->sub_vendor_id,
288 version->impl_ver);
289 if (!proto) {
290 int ret;
291
292 pr_debug("Looking for '" SCMI_VENDOR_MODULE_ALIAS_FMT "'\n",
293 protocol_id, version->vendor_id);
294
295 /* Note that vendor_id is mandatory for vendor protocols */
296 ret = request_module(SCMI_VENDOR_MODULE_ALIAS_FMT,
297 protocol_id, version->vendor_id);
298 if (ret) {
299 pr_warn("Problem loading module for protocol 0x%x\n",
300 protocol_id);
301 return NULL;
302 }
303
304 /* Lookup again, once modules loaded */
305 proto = scmi_vendor_protocol_lookup(protocol_id,
306 version->vendor_id,
307 version->sub_vendor_id,
308 version->impl_ver);
309 }
310
311 if (proto)
312 pr_info("Loaded SCMI Vendor Protocol 0x%x - %s %s %X\n",
313 protocol_id, proto->vendor_id ?: "",
314 proto->sub_vendor_id ?: "", proto->impl_ver);
315
316 return proto;
317 }
318
319 static const struct scmi_protocol *
scmi_protocol_get(int protocol_id,struct scmi_revision_info * version)320 scmi_protocol_get(int protocol_id, struct scmi_revision_info *version)
321 {
322 const struct scmi_protocol *proto = NULL;
323
324 if (protocol_id < SCMI_PROTOCOL_VENDOR_BASE)
325 proto = xa_load(&scmi_protocols, protocol_id);
326 else
327 proto = scmi_vendor_protocol_get(protocol_id, version);
328
329 if (!proto || !try_module_get(proto->owner)) {
330 pr_warn("SCMI Protocol 0x%x not found!\n", protocol_id);
331 return NULL;
332 }
333
334 pr_debug("Found SCMI Protocol 0x%x\n", protocol_id);
335
336 return proto;
337 }
338
scmi_protocol_put(const struct scmi_protocol * proto)339 static void scmi_protocol_put(const struct scmi_protocol *proto)
340 {
341 if (proto)
342 module_put(proto->owner);
343 }
344
scmi_vendor_protocol_check(const struct scmi_protocol * proto)345 static int scmi_vendor_protocol_check(const struct scmi_protocol *proto)
346 {
347 if (!proto->vendor_id) {
348 pr_err("missing vendor_id for protocol 0x%x\n", proto->id);
349 return -EINVAL;
350 }
351
352 if (strlen(proto->vendor_id) >= SCMI_SHORT_NAME_MAX_SIZE) {
353 pr_err("malformed vendor_id for protocol 0x%x\n", proto->id);
354 return -EINVAL;
355 }
356
357 if (proto->sub_vendor_id &&
358 strlen(proto->sub_vendor_id) >= SCMI_SHORT_NAME_MAX_SIZE) {
359 pr_err("malformed sub_vendor_id for protocol 0x%x\n",
360 proto->id);
361 return -EINVAL;
362 }
363
364 return 0;
365 }
366
scmi_protocol_register(const struct scmi_protocol * proto)367 int scmi_protocol_register(const struct scmi_protocol *proto)
368 {
369 int ret;
370 unsigned long key;
371
372 if (!proto) {
373 pr_err("invalid protocol\n");
374 return -EINVAL;
375 }
376
377 if (!proto->instance_init) {
378 pr_err("missing init for protocol 0x%x\n", proto->id);
379 return -EINVAL;
380 }
381
382 if (proto->id >= SCMI_PROTOCOL_VENDOR_BASE &&
383 scmi_vendor_protocol_check(proto))
384 return -EINVAL;
385
386 /*
387 * Calculate a protocol key to register this protocol with the core;
388 * key value 0 is considered invalid.
389 */
390 key = scmi_protocol_key_calculate(proto->id, proto->vendor_id,
391 proto->sub_vendor_id,
392 proto->impl_ver);
393 if (!key)
394 return -EINVAL;
395
396 ret = xa_insert(&scmi_protocols, key, (void *)proto, GFP_KERNEL);
397 if (ret) {
398 pr_err("unable to allocate SCMI protocol slot for 0x%x - err %d\n",
399 proto->id, ret);
400 return ret;
401 }
402
403 pr_debug("Registered SCMI Protocol 0x%x - %s %s 0x%08X\n",
404 proto->id, proto->vendor_id, proto->sub_vendor_id,
405 proto->impl_ver);
406
407 return 0;
408 }
409 EXPORT_SYMBOL_GPL(scmi_protocol_register);
410
scmi_protocol_unregister(const struct scmi_protocol * proto)411 void scmi_protocol_unregister(const struct scmi_protocol *proto)
412 {
413 unsigned long key;
414
415 key = scmi_protocol_key_calculate(proto->id, proto->vendor_id,
416 proto->sub_vendor_id,
417 proto->impl_ver);
418 if (!key)
419 return;
420
421 xa_erase(&scmi_protocols, key);
422
423 pr_debug("Unregistered SCMI Protocol 0x%x\n", proto->id);
424 }
425 EXPORT_SYMBOL_GPL(scmi_protocol_unregister);
426
427 /**
428 * scmi_create_protocol_devices - Create devices for all pending requests for
429 * this SCMI instance.
430 *
431 * @np: The device node describing the protocol
432 * @info: The SCMI instance descriptor
433 * @prot_id: The protocol ID
434 * @name: The optional name of the device to be created: if not provided this
435 * call will lead to the creation of all the devices currently requested
436 * for the specified protocol.
437 */
scmi_create_protocol_devices(struct device_node * np,struct scmi_info * info,int prot_id,const char * name)438 static void scmi_create_protocol_devices(struct device_node *np,
439 struct scmi_info *info,
440 int prot_id, const char *name)
441 {
442 struct scmi_device *sdev;
443
444 mutex_lock(&info->devreq_mtx);
445 sdev = scmi_device_create(np, info->dev, prot_id, name);
446 if (name && !sdev)
447 dev_err(info->dev,
448 "failed to create device for protocol 0x%X (%s)\n",
449 prot_id, name);
450 mutex_unlock(&info->devreq_mtx);
451 }
452
scmi_destroy_protocol_devices(struct scmi_info * info,int prot_id,const char * name)453 static void scmi_destroy_protocol_devices(struct scmi_info *info,
454 int prot_id, const char *name)
455 {
456 mutex_lock(&info->devreq_mtx);
457 scmi_device_destroy(info->dev, prot_id, name);
458 mutex_unlock(&info->devreq_mtx);
459 }
460
scmi_notification_instance_data_set(const struct scmi_handle * handle,void * priv)461 void scmi_notification_instance_data_set(const struct scmi_handle *handle,
462 void *priv)
463 {
464 struct scmi_info *info = handle_to_scmi_info(handle);
465
466 info->notify_priv = priv;
467 /* Ensure updated protocol private date are visible */
468 smp_wmb();
469 }
470
scmi_notification_instance_data_get(const struct scmi_handle * handle)471 void *scmi_notification_instance_data_get(const struct scmi_handle *handle)
472 {
473 struct scmi_info *info = handle_to_scmi_info(handle);
474
475 /* Ensure protocols_private_data has been updated */
476 smp_rmb();
477 return info->notify_priv;
478 }
479
480 /**
481 * scmi_xfer_token_set - Reserve and set new token for the xfer at hand
482 *
483 * @minfo: Pointer to Tx/Rx Message management info based on channel type
484 * @xfer: The xfer to act upon
485 *
486 * Pick the next unused monotonically increasing token and set it into
487 * xfer->hdr.seq: picking a monotonically increasing value avoids immediate
488 * reuse of freshly completed or timed-out xfers, thus mitigating the risk
489 * of incorrect association of a late and expired xfer with a live in-flight
490 * transaction, both happening to re-use the same token identifier.
491 *
492 * Since platform is NOT required to answer our request in-order we should
493 * account for a few rare but possible scenarios:
494 *
495 * - exactly 'next_token' may be NOT available so pick xfer_id >= next_token
496 * using find_next_zero_bit() starting from candidate next_token bit
497 *
498 * - all tokens ahead upto (MSG_TOKEN_ID_MASK - 1) are used in-flight but we
499 * are plenty of free tokens at start, so try a second pass using
500 * find_next_zero_bit() and starting from 0.
501 *
502 * X = used in-flight
503 *
504 * Normal
505 * ------
506 *
507 * |- xfer_id picked
508 * -----------+----------------------------------------------------------
509 * | | |X|X|X| | | | | | ... ... ... ... ... ... ... ... ... ... ...|X|X|
510 * ----------------------------------------------------------------------
511 * ^
512 * |- next_token
513 *
514 * Out-of-order pending at start
515 * -----------------------------
516 *
517 * |- xfer_id picked, last_token fixed
518 * -----+----------------------------------------------------------------
519 * |X|X| | | | |X|X| ... ... ... ... ... ... ... ... ... ... ... ...|X| |
520 * ----------------------------------------------------------------------
521 * ^
522 * |- next_token
523 *
524 *
525 * Out-of-order pending at end
526 * ---------------------------
527 *
528 * |- xfer_id picked, last_token fixed
529 * -----+----------------------------------------------------------------
530 * |X|X| | | | |X|X| ... ... ... ... ... ... ... ... ... ... |X|X|X||X|X|
531 * ----------------------------------------------------------------------
532 * ^
533 * |- next_token
534 *
535 * Context: Assumes to be called with @xfer_lock already acquired.
536 *
537 * Return: 0 on Success or error
538 */
scmi_xfer_token_set(struct scmi_xfers_info * minfo,struct scmi_xfer * xfer)539 static int scmi_xfer_token_set(struct scmi_xfers_info *minfo,
540 struct scmi_xfer *xfer)
541 {
542 unsigned long xfer_id, next_token;
543
544 /*
545 * Pick a candidate monotonic token in range [0, MSG_TOKEN_MAX - 1]
546 * using the pre-allocated transfer_id as a base.
547 * Note that the global transfer_id is shared across all message types
548 * so there could be holes in the allocated set of monotonic sequence
549 * numbers, but that is going to limit the effectiveness of the
550 * mitigation only in very rare limit conditions.
551 */
552 next_token = (xfer->transfer_id & (MSG_TOKEN_MAX - 1));
553
554 /* Pick the next available xfer_id >= next_token */
555 xfer_id = find_next_zero_bit(minfo->xfer_alloc_table,
556 MSG_TOKEN_MAX, next_token);
557 if (xfer_id == MSG_TOKEN_MAX) {
558 /*
559 * After heavily out-of-order responses, there are no free
560 * tokens ahead, but only at start of xfer_alloc_table so
561 * try again from the beginning.
562 */
563 xfer_id = find_next_zero_bit(minfo->xfer_alloc_table,
564 MSG_TOKEN_MAX, 0);
565 /*
566 * Something is wrong if we got here since there can be a
567 * maximum number of (MSG_TOKEN_MAX - 1) in-flight messages
568 * but we have not found any free token [0, MSG_TOKEN_MAX - 1].
569 */
570 if (WARN_ON_ONCE(xfer_id == MSG_TOKEN_MAX))
571 return -ENOMEM;
572 }
573
574 /* Update +/- last_token accordingly if we skipped some hole */
575 if (xfer_id != next_token)
576 atomic_add((int)(xfer_id - next_token), &transfer_last_id);
577
578 xfer->hdr.seq = (u16)xfer_id;
579
580 return 0;
581 }
582
583 /**
584 * scmi_xfer_token_clear - Release the token
585 *
586 * @minfo: Pointer to Tx/Rx Message management info based on channel type
587 * @xfer: The xfer to act upon
588 */
scmi_xfer_token_clear(struct scmi_xfers_info * minfo,struct scmi_xfer * xfer)589 static inline void scmi_xfer_token_clear(struct scmi_xfers_info *minfo,
590 struct scmi_xfer *xfer)
591 {
592 clear_bit(xfer->hdr.seq, minfo->xfer_alloc_table);
593 }
594
595 /**
596 * scmi_xfer_inflight_register_unlocked - Register the xfer as in-flight
597 *
598 * @xfer: The xfer to register
599 * @minfo: Pointer to Tx/Rx Message management info based on channel type
600 *
601 * Note that this helper assumes that the xfer to be registered as in-flight
602 * had been built using an xfer sequence number which still corresponds to a
603 * free slot in the xfer_alloc_table.
604 *
605 * Context: Assumes to be called with @xfer_lock already acquired.
606 */
607 static inline void
scmi_xfer_inflight_register_unlocked(struct scmi_xfer * xfer,struct scmi_xfers_info * minfo)608 scmi_xfer_inflight_register_unlocked(struct scmi_xfer *xfer,
609 struct scmi_xfers_info *minfo)
610 {
611 /* Set in-flight */
612 set_bit(xfer->hdr.seq, minfo->xfer_alloc_table);
613 hash_add(minfo->pending_xfers, &xfer->node, xfer->hdr.seq);
614 xfer->pending = true;
615 }
616
617 /**
618 * scmi_xfer_inflight_register - Try to register an xfer as in-flight
619 *
620 * @xfer: The xfer to register
621 * @minfo: Pointer to Tx/Rx Message management info based on channel type
622 *
623 * Note that this helper does NOT assume anything about the sequence number
624 * that was baked into the provided xfer, so it checks at first if it can
625 * be mapped to a free slot and fails with an error if another xfer with the
626 * same sequence number is currently still registered as in-flight.
627 *
628 * Return: 0 on Success or -EBUSY if sequence number embedded in the xfer
629 * could not rbe mapped to a free slot in the xfer_alloc_table.
630 */
scmi_xfer_inflight_register(struct scmi_xfer * xfer,struct scmi_xfers_info * minfo)631 static int scmi_xfer_inflight_register(struct scmi_xfer *xfer,
632 struct scmi_xfers_info *minfo)
633 {
634 int ret = 0;
635 unsigned long flags;
636
637 spin_lock_irqsave(&minfo->xfer_lock, flags);
638 if (!test_bit(xfer->hdr.seq, minfo->xfer_alloc_table))
639 scmi_xfer_inflight_register_unlocked(xfer, minfo);
640 else
641 ret = -EBUSY;
642 spin_unlock_irqrestore(&minfo->xfer_lock, flags);
643
644 return ret;
645 }
646
647 /**
648 * scmi_xfer_raw_inflight_register - An helper to register the given xfer as in
649 * flight on the TX channel, if possible.
650 *
651 * @handle: Pointer to SCMI entity handle
652 * @xfer: The xfer to register
653 *
654 * Return: 0 on Success, error otherwise
655 */
scmi_xfer_raw_inflight_register(const struct scmi_handle * handle,struct scmi_xfer * xfer)656 int scmi_xfer_raw_inflight_register(const struct scmi_handle *handle,
657 struct scmi_xfer *xfer)
658 {
659 struct scmi_info *info = handle_to_scmi_info(handle);
660
661 return scmi_xfer_inflight_register(xfer, &info->tx_minfo);
662 }
663
664 /**
665 * scmi_xfer_pending_set - Pick a proper sequence number and mark the xfer
666 * as pending in-flight
667 *
668 * @xfer: The xfer to act upon
669 * @minfo: Pointer to Tx/Rx Message management info based on channel type
670 *
671 * Return: 0 on Success or error otherwise
672 */
scmi_xfer_pending_set(struct scmi_xfer * xfer,struct scmi_xfers_info * minfo)673 static inline int scmi_xfer_pending_set(struct scmi_xfer *xfer,
674 struct scmi_xfers_info *minfo)
675 {
676 int ret;
677 unsigned long flags;
678
679 spin_lock_irqsave(&minfo->xfer_lock, flags);
680 /* Set a new monotonic token as the xfer sequence number */
681 ret = scmi_xfer_token_set(minfo, xfer);
682 if (!ret)
683 scmi_xfer_inflight_register_unlocked(xfer, minfo);
684 spin_unlock_irqrestore(&minfo->xfer_lock, flags);
685
686 return ret;
687 }
688
689 /**
690 * scmi_xfer_get() - Allocate one message
691 *
692 * @handle: Pointer to SCMI entity handle
693 * @minfo: Pointer to Tx/Rx Message management info based on channel type
694 *
695 * Helper function which is used by various message functions that are
696 * exposed to clients of this driver for allocating a message traffic event.
697 *
698 * Picks an xfer from the free list @free_xfers (if any available) and perform
699 * a basic initialization.
700 *
701 * Note that, at this point, still no sequence number is assigned to the
702 * allocated xfer, nor it is registered as a pending transaction.
703 *
704 * The successfully initialized xfer is refcounted.
705 *
706 * Context: Holds @xfer_lock while manipulating @free_xfers.
707 *
708 * Return: An initialized xfer if all went fine, else pointer error.
709 */
scmi_xfer_get(const struct scmi_handle * handle,struct scmi_xfers_info * minfo)710 static struct scmi_xfer *scmi_xfer_get(const struct scmi_handle *handle,
711 struct scmi_xfers_info *minfo)
712 {
713 unsigned long flags;
714 struct scmi_xfer *xfer;
715
716 spin_lock_irqsave(&minfo->xfer_lock, flags);
717 if (hlist_empty(&minfo->free_xfers)) {
718 spin_unlock_irqrestore(&minfo->xfer_lock, flags);
719 return ERR_PTR(-ENOMEM);
720 }
721
722 /* grab an xfer from the free_list */
723 xfer = hlist_entry(minfo->free_xfers.first, struct scmi_xfer, node);
724 hlist_del_init(&xfer->node);
725
726 /*
727 * Allocate transfer_id early so that can be used also as base for
728 * monotonic sequence number generation if needed.
729 */
730 xfer->transfer_id = atomic_inc_return(&transfer_last_id);
731
732 refcount_set(&xfer->users, 1);
733 atomic_set(&xfer->busy, SCMI_XFER_FREE);
734 spin_unlock_irqrestore(&minfo->xfer_lock, flags);
735
736 return xfer;
737 }
738
739 /**
740 * scmi_xfer_raw_get - Helper to get a bare free xfer from the TX channel
741 *
742 * @handle: Pointer to SCMI entity handle
743 *
744 * Note that xfer is taken from the TX channel structures.
745 *
746 * Return: A valid xfer on Success, or an error-pointer otherwise
747 */
scmi_xfer_raw_get(const struct scmi_handle * handle)748 struct scmi_xfer *scmi_xfer_raw_get(const struct scmi_handle *handle)
749 {
750 struct scmi_xfer *xfer;
751 struct scmi_info *info = handle_to_scmi_info(handle);
752
753 xfer = scmi_xfer_get(handle, &info->tx_minfo);
754 if (!IS_ERR(xfer))
755 xfer->flags |= SCMI_XFER_FLAG_IS_RAW;
756
757 return xfer;
758 }
759
760 /**
761 * scmi_xfer_raw_channel_get - Helper to get a reference to the proper channel
762 * to use for a specific protocol_id Raw transaction.
763 *
764 * @handle: Pointer to SCMI entity handle
765 * @protocol_id: Identifier of the protocol
766 *
767 * Note that in a regular SCMI stack, usually, a protocol has to be defined in
768 * the DT to have an associated channel and be usable; but in Raw mode any
769 * protocol in range is allowed, re-using the Base channel, so as to enable
770 * fuzzing on any protocol without the need of a fully compiled DT.
771 *
772 * Return: A reference to the channel to use, or an ERR_PTR
773 */
774 struct scmi_chan_info *
scmi_xfer_raw_channel_get(const struct scmi_handle * handle,u8 protocol_id)775 scmi_xfer_raw_channel_get(const struct scmi_handle *handle, u8 protocol_id)
776 {
777 struct scmi_chan_info *cinfo;
778 struct scmi_info *info = handle_to_scmi_info(handle);
779
780 cinfo = idr_find(&info->tx_idr, protocol_id);
781 if (!cinfo) {
782 if (protocol_id == SCMI_PROTOCOL_BASE)
783 return ERR_PTR(-EINVAL);
784 /* Use Base channel for protocols not defined for DT */
785 cinfo = idr_find(&info->tx_idr, SCMI_PROTOCOL_BASE);
786 if (!cinfo)
787 return ERR_PTR(-EINVAL);
788 dev_warn_once(handle->dev,
789 "Using Base channel for protocol 0x%X\n",
790 protocol_id);
791 }
792
793 return cinfo;
794 }
795
796 /**
797 * __scmi_xfer_put() - Release a message
798 *
799 * @minfo: Pointer to Tx/Rx Message management info based on channel type
800 * @xfer: message that was reserved by scmi_xfer_get
801 *
802 * After refcount check, possibly release an xfer, clearing the token slot,
803 * removing xfer from @pending_xfers and putting it back into free_xfers.
804 *
805 * This holds a spinlock to maintain integrity of internal data structures.
806 */
807 static void
__scmi_xfer_put(struct scmi_xfers_info * minfo,struct scmi_xfer * xfer)808 __scmi_xfer_put(struct scmi_xfers_info *minfo, struct scmi_xfer *xfer)
809 {
810 unsigned long flags;
811
812 spin_lock_irqsave(&minfo->xfer_lock, flags);
813 if (refcount_dec_and_test(&xfer->users)) {
814 if (xfer->pending) {
815 scmi_xfer_token_clear(minfo, xfer);
816 hash_del(&xfer->node);
817 xfer->pending = false;
818 }
819 hlist_add_head(&xfer->node, &minfo->free_xfers);
820 }
821 spin_unlock_irqrestore(&minfo->xfer_lock, flags);
822 }
823
824 /**
825 * scmi_xfer_raw_put - Release an xfer that was taken by @scmi_xfer_raw_get
826 *
827 * @handle: Pointer to SCMI entity handle
828 * @xfer: A reference to the xfer to put
829 *
830 * Note that as with other xfer_put() handlers the xfer is really effectively
831 * released only if there are no more users on the system.
832 */
scmi_xfer_raw_put(const struct scmi_handle * handle,struct scmi_xfer * xfer)833 void scmi_xfer_raw_put(const struct scmi_handle *handle, struct scmi_xfer *xfer)
834 {
835 struct scmi_info *info = handle_to_scmi_info(handle);
836
837 xfer->flags &= ~SCMI_XFER_FLAG_IS_RAW;
838 xfer->flags &= ~SCMI_XFER_FLAG_CHAN_SET;
839 return __scmi_xfer_put(&info->tx_minfo, xfer);
840 }
841
842 /**
843 * scmi_xfer_lookup_unlocked - Helper to lookup an xfer_id
844 *
845 * @minfo: Pointer to Tx/Rx Message management info based on channel type
846 * @xfer_id: Token ID to lookup in @pending_xfers
847 *
848 * Refcounting is untouched.
849 *
850 * Context: Assumes to be called with @xfer_lock already acquired.
851 *
852 * Return: A valid xfer on Success or error otherwise
853 */
854 static struct scmi_xfer *
scmi_xfer_lookup_unlocked(struct scmi_xfers_info * minfo,u16 xfer_id)855 scmi_xfer_lookup_unlocked(struct scmi_xfers_info *minfo, u16 xfer_id)
856 {
857 struct scmi_xfer *xfer = NULL;
858
859 if (test_bit(xfer_id, minfo->xfer_alloc_table))
860 xfer = XFER_FIND(minfo->pending_xfers, xfer_id);
861
862 return xfer ?: ERR_PTR(-EINVAL);
863 }
864
865 /**
866 * scmi_bad_message_trace - A helper to trace weird messages
867 *
868 * @cinfo: A reference to the channel descriptor on which the message was
869 * received
870 * @msg_hdr: Message header to track
871 * @err: A specific error code used as a status value in traces.
872 *
873 * This helper can be used to trace any kind of weird, incomplete, unexpected,
874 * timed-out message that arrives and as such, can be traced only referring to
875 * the header content, since the payload is missing/unreliable.
876 */
scmi_bad_message_trace(struct scmi_chan_info * cinfo,u32 msg_hdr,enum scmi_bad_msg err)877 static void scmi_bad_message_trace(struct scmi_chan_info *cinfo, u32 msg_hdr,
878 enum scmi_bad_msg err)
879 {
880 char *tag;
881 struct scmi_info *info = handle_to_scmi_info(cinfo->handle);
882
883 switch (MSG_XTRACT_TYPE(msg_hdr)) {
884 case MSG_TYPE_COMMAND:
885 tag = "!RESP";
886 break;
887 case MSG_TYPE_DELAYED_RESP:
888 tag = "!DLYD";
889 break;
890 case MSG_TYPE_NOTIFICATION:
891 tag = "!NOTI";
892 break;
893 default:
894 tag = "!UNKN";
895 break;
896 }
897
898 trace_scmi_msg_dump(info->id, cinfo->id,
899 MSG_XTRACT_PROT_ID(msg_hdr),
900 MSG_XTRACT_ID(msg_hdr), tag,
901 MSG_XTRACT_TOKEN(msg_hdr), err, NULL, 0);
902 }
903
904 /**
905 * scmi_msg_response_validate - Validate message type against state of related
906 * xfer
907 *
908 * @cinfo: A reference to the channel descriptor.
909 * @msg_type: Message type to check
910 * @xfer: A reference to the xfer to validate against @msg_type
911 *
912 * This function checks if @msg_type is congruent with the current state of
913 * a pending @xfer; if an asynchronous delayed response is received before the
914 * related synchronous response (Out-of-Order Delayed Response) the missing
915 * synchronous response is assumed to be OK and completed, carrying on with the
916 * Delayed Response: this is done to address the case in which the underlying
917 * SCMI transport can deliver such out-of-order responses.
918 *
919 * Context: Assumes to be called with xfer->lock already acquired.
920 *
921 * Return: 0 on Success, error otherwise
922 */
scmi_msg_response_validate(struct scmi_chan_info * cinfo,u8 msg_type,struct scmi_xfer * xfer)923 static inline int scmi_msg_response_validate(struct scmi_chan_info *cinfo,
924 u8 msg_type,
925 struct scmi_xfer *xfer)
926 {
927 /*
928 * Even if a response was indeed expected on this slot at this point,
929 * a buggy platform could wrongly reply feeding us an unexpected
930 * delayed response we're not prepared to handle: bail-out safely
931 * blaming firmware.
932 */
933 if (msg_type == MSG_TYPE_DELAYED_RESP && !xfer->async_done) {
934 dev_err(cinfo->dev,
935 "Delayed Response for %d not expected! Buggy F/W ?\n",
936 xfer->hdr.seq);
937 return -EINVAL;
938 }
939
940 switch (xfer->state) {
941 case SCMI_XFER_SENT_OK:
942 if (msg_type == MSG_TYPE_DELAYED_RESP) {
943 /*
944 * Delayed Response expected but delivered earlier.
945 * Assume message RESPONSE was OK and skip state.
946 */
947 xfer->hdr.status = SCMI_SUCCESS;
948 xfer->state = SCMI_XFER_RESP_OK;
949 complete(&xfer->done);
950 dev_warn(cinfo->dev,
951 "Received valid OoO Delayed Response for %d\n",
952 xfer->hdr.seq);
953 }
954 break;
955 case SCMI_XFER_RESP_OK:
956 if (msg_type != MSG_TYPE_DELAYED_RESP)
957 return -EINVAL;
958 break;
959 case SCMI_XFER_DRESP_OK:
960 /* No further message expected once in SCMI_XFER_DRESP_OK */
961 return -EINVAL;
962 }
963
964 return 0;
965 }
966
967 /**
968 * scmi_xfer_state_update - Update xfer state
969 *
970 * @xfer: A reference to the xfer to update
971 * @msg_type: Type of message being processed.
972 *
973 * Note that this message is assumed to have been already successfully validated
974 * by @scmi_msg_response_validate(), so here we just update the state.
975 *
976 * Context: Assumes to be called on an xfer exclusively acquired using the
977 * busy flag.
978 */
scmi_xfer_state_update(struct scmi_xfer * xfer,u8 msg_type)979 static inline void scmi_xfer_state_update(struct scmi_xfer *xfer, u8 msg_type)
980 {
981 xfer->hdr.type = msg_type;
982
983 /* Unknown command types were already discarded earlier */
984 if (xfer->hdr.type == MSG_TYPE_COMMAND)
985 xfer->state = SCMI_XFER_RESP_OK;
986 else
987 xfer->state = SCMI_XFER_DRESP_OK;
988 }
989
scmi_xfer_acquired(struct scmi_xfer * xfer)990 static bool scmi_xfer_acquired(struct scmi_xfer *xfer)
991 {
992 int ret;
993
994 ret = atomic_cmpxchg(&xfer->busy, SCMI_XFER_FREE, SCMI_XFER_BUSY);
995
996 return ret == SCMI_XFER_FREE;
997 }
998
999 /**
1000 * scmi_xfer_command_acquire - Helper to lookup and acquire a command xfer
1001 *
1002 * @cinfo: A reference to the channel descriptor.
1003 * @msg_hdr: A message header to use as lookup key
1004 *
1005 * When a valid xfer is found for the sequence number embedded in the provided
1006 * msg_hdr, reference counting is properly updated and exclusive access to this
1007 * xfer is granted till released with @scmi_xfer_command_release.
1008 *
1009 * Return: A valid @xfer on Success or error otherwise.
1010 */
1011 static inline struct scmi_xfer *
scmi_xfer_command_acquire(struct scmi_chan_info * cinfo,u32 msg_hdr)1012 scmi_xfer_command_acquire(struct scmi_chan_info *cinfo, u32 msg_hdr)
1013 {
1014 int ret;
1015 unsigned long flags;
1016 struct scmi_xfer *xfer;
1017 struct scmi_info *info = handle_to_scmi_info(cinfo->handle);
1018 struct scmi_xfers_info *minfo = &info->tx_minfo;
1019 u8 msg_type = MSG_XTRACT_TYPE(msg_hdr);
1020 u16 xfer_id = MSG_XTRACT_TOKEN(msg_hdr);
1021
1022 /* Are we even expecting this? */
1023 spin_lock_irqsave(&minfo->xfer_lock, flags);
1024 xfer = scmi_xfer_lookup_unlocked(minfo, xfer_id);
1025 if (IS_ERR(xfer)) {
1026 dev_err(cinfo->dev,
1027 "Message for %d type %d is not expected!\n",
1028 xfer_id, msg_type);
1029 spin_unlock_irqrestore(&minfo->xfer_lock, flags);
1030
1031 scmi_bad_message_trace(cinfo, msg_hdr, MSG_UNEXPECTED);
1032 scmi_inc_count(info->dbg->counters, ERR_MSG_UNEXPECTED);
1033
1034 return xfer;
1035 }
1036 refcount_inc(&xfer->users);
1037 spin_unlock_irqrestore(&minfo->xfer_lock, flags);
1038
1039 spin_lock_irqsave(&xfer->lock, flags);
1040 ret = scmi_msg_response_validate(cinfo, msg_type, xfer);
1041 /*
1042 * If a pending xfer was found which was also in a congruent state with
1043 * the received message, acquire exclusive access to it setting the busy
1044 * flag.
1045 * Spins only on the rare limit condition of concurrent reception of
1046 * RESP and DRESP for the same xfer.
1047 */
1048 if (!ret) {
1049 spin_until_cond(scmi_xfer_acquired(xfer));
1050 scmi_xfer_state_update(xfer, msg_type);
1051 }
1052 spin_unlock_irqrestore(&xfer->lock, flags);
1053
1054 if (ret) {
1055 dev_err(cinfo->dev,
1056 "Invalid message type:%d for %d - HDR:0x%X state:%d\n",
1057 msg_type, xfer_id, msg_hdr, xfer->state);
1058
1059 scmi_bad_message_trace(cinfo, msg_hdr, MSG_INVALID);
1060 scmi_inc_count(info->dbg->counters, ERR_MSG_INVALID);
1061
1062 /* On error the refcount incremented above has to be dropped */
1063 __scmi_xfer_put(minfo, xfer);
1064 xfer = ERR_PTR(-EINVAL);
1065 }
1066
1067 return xfer;
1068 }
1069
scmi_xfer_command_release(struct scmi_info * info,struct scmi_xfer * xfer)1070 static inline void scmi_xfer_command_release(struct scmi_info *info,
1071 struct scmi_xfer *xfer)
1072 {
1073 atomic_set(&xfer->busy, SCMI_XFER_FREE);
1074 __scmi_xfer_put(&info->tx_minfo, xfer);
1075 }
1076
scmi_clear_channel(struct scmi_info * info,struct scmi_chan_info * cinfo)1077 static inline void scmi_clear_channel(struct scmi_info *info,
1078 struct scmi_chan_info *cinfo)
1079 {
1080 if (!cinfo->is_p2a) {
1081 dev_warn(cinfo->dev, "Invalid clear on A2P channel !\n");
1082 return;
1083 }
1084
1085 if (info->desc->ops->clear_channel)
1086 info->desc->ops->clear_channel(cinfo);
1087 }
1088
scmi_handle_notification(struct scmi_chan_info * cinfo,u32 msg_hdr,void * priv)1089 static void scmi_handle_notification(struct scmi_chan_info *cinfo,
1090 u32 msg_hdr, void *priv)
1091 {
1092 struct scmi_xfer *xfer;
1093 struct device *dev = cinfo->dev;
1094 struct scmi_info *info = handle_to_scmi_info(cinfo->handle);
1095 struct scmi_xfers_info *minfo = &info->rx_minfo;
1096 ktime_t ts;
1097
1098 ts = ktime_get_boottime();
1099 xfer = scmi_xfer_get(cinfo->handle, minfo);
1100 if (IS_ERR(xfer)) {
1101 dev_err(dev, "failed to get free message slot (%ld)\n",
1102 PTR_ERR(xfer));
1103
1104 scmi_bad_message_trace(cinfo, msg_hdr, MSG_NOMEM);
1105 scmi_inc_count(info->dbg->counters, ERR_MSG_NOMEM);
1106
1107 scmi_clear_channel(info, cinfo);
1108 return;
1109 }
1110
1111 unpack_scmi_header(msg_hdr, &xfer->hdr);
1112 if (priv)
1113 /* Ensure order between xfer->priv store and following ops */
1114 smp_store_mb(xfer->priv, priv);
1115 info->desc->ops->fetch_notification(cinfo, info->desc->max_msg_size,
1116 xfer);
1117
1118 trace_scmi_msg_dump(info->id, cinfo->id, xfer->hdr.protocol_id,
1119 xfer->hdr.id, "NOTI", xfer->hdr.seq,
1120 xfer->hdr.status, xfer->rx.buf, xfer->rx.len);
1121 scmi_inc_count(info->dbg->counters, NOTIFICATION_OK);
1122
1123 scmi_notify(cinfo->handle, xfer->hdr.protocol_id,
1124 xfer->hdr.id, xfer->rx.buf, xfer->rx.len, ts);
1125
1126 trace_scmi_rx_done(xfer->transfer_id, xfer->hdr.id,
1127 xfer->hdr.protocol_id, xfer->hdr.seq,
1128 MSG_TYPE_NOTIFICATION);
1129
1130 if (IS_ENABLED(CONFIG_ARM_SCMI_RAW_MODE_SUPPORT)) {
1131 xfer->hdr.seq = MSG_XTRACT_TOKEN(msg_hdr);
1132 scmi_raw_message_report(info->raw, xfer, SCMI_RAW_NOTIF_QUEUE,
1133 cinfo->id);
1134 }
1135
1136 __scmi_xfer_put(minfo, xfer);
1137
1138 scmi_clear_channel(info, cinfo);
1139 }
1140
scmi_handle_response(struct scmi_chan_info * cinfo,u32 msg_hdr,void * priv)1141 static void scmi_handle_response(struct scmi_chan_info *cinfo,
1142 u32 msg_hdr, void *priv)
1143 {
1144 struct scmi_xfer *xfer;
1145 struct scmi_info *info = handle_to_scmi_info(cinfo->handle);
1146
1147 xfer = scmi_xfer_command_acquire(cinfo, msg_hdr);
1148 if (IS_ERR(xfer)) {
1149 if (IS_ENABLED(CONFIG_ARM_SCMI_RAW_MODE_SUPPORT))
1150 scmi_raw_error_report(info->raw, cinfo, msg_hdr, priv);
1151
1152 if (MSG_XTRACT_TYPE(msg_hdr) == MSG_TYPE_DELAYED_RESP)
1153 scmi_clear_channel(info, cinfo);
1154 return;
1155 }
1156
1157 /* rx.len could be shrunk in the sync do_xfer, so reset to maxsz */
1158 if (xfer->hdr.type == MSG_TYPE_DELAYED_RESP)
1159 xfer->rx.len = info->desc->max_msg_size;
1160
1161 if (priv)
1162 /* Ensure order between xfer->priv store and following ops */
1163 smp_store_mb(xfer->priv, priv);
1164 info->desc->ops->fetch_response(cinfo, xfer);
1165
1166 trace_scmi_msg_dump(info->id, cinfo->id, xfer->hdr.protocol_id,
1167 xfer->hdr.id,
1168 xfer->hdr.type == MSG_TYPE_DELAYED_RESP ?
1169 (!SCMI_XFER_IS_RAW(xfer) ? "DLYD" : "dlyd") :
1170 (!SCMI_XFER_IS_RAW(xfer) ? "RESP" : "resp"),
1171 xfer->hdr.seq, xfer->hdr.status,
1172 xfer->rx.buf, xfer->rx.len);
1173
1174 trace_scmi_rx_done(xfer->transfer_id, xfer->hdr.id,
1175 xfer->hdr.protocol_id, xfer->hdr.seq,
1176 xfer->hdr.type);
1177
1178 if (xfer->hdr.type == MSG_TYPE_DELAYED_RESP) {
1179 scmi_clear_channel(info, cinfo);
1180 complete(xfer->async_done);
1181 scmi_inc_count(info->dbg->counters, DELAYED_RESPONSE_OK);
1182 } else {
1183 complete(&xfer->done);
1184 scmi_inc_count(info->dbg->counters, RESPONSE_OK);
1185 }
1186
1187 if (IS_ENABLED(CONFIG_ARM_SCMI_RAW_MODE_SUPPORT)) {
1188 /*
1189 * When in polling mode avoid to queue the Raw xfer on the IRQ
1190 * RX path since it will be already queued at the end of the TX
1191 * poll loop.
1192 */
1193 if (!xfer->hdr.poll_completion)
1194 scmi_raw_message_report(info->raw, xfer,
1195 SCMI_RAW_REPLY_QUEUE,
1196 cinfo->id);
1197 }
1198
1199 scmi_xfer_command_release(info, xfer);
1200 }
1201
1202 /**
1203 * scmi_rx_callback() - callback for receiving messages
1204 *
1205 * @cinfo: SCMI channel info
1206 * @msg_hdr: Message header
1207 * @priv: Transport specific private data.
1208 *
1209 * Processes one received message to appropriate transfer information and
1210 * signals completion of the transfer.
1211 *
1212 * NOTE: This function will be invoked in IRQ context, hence should be
1213 * as optimal as possible.
1214 */
scmi_rx_callback(struct scmi_chan_info * cinfo,u32 msg_hdr,void * priv)1215 static void scmi_rx_callback(struct scmi_chan_info *cinfo, u32 msg_hdr,
1216 void *priv)
1217 {
1218 u8 msg_type = MSG_XTRACT_TYPE(msg_hdr);
1219
1220 switch (msg_type) {
1221 case MSG_TYPE_NOTIFICATION:
1222 scmi_handle_notification(cinfo, msg_hdr, priv);
1223 break;
1224 case MSG_TYPE_COMMAND:
1225 case MSG_TYPE_DELAYED_RESP:
1226 scmi_handle_response(cinfo, msg_hdr, priv);
1227 break;
1228 default:
1229 WARN_ONCE(1, "received unknown msg_type:%d\n", msg_type);
1230 scmi_bad_message_trace(cinfo, msg_hdr, MSG_UNKNOWN);
1231 break;
1232 }
1233 }
1234
1235 /**
1236 * xfer_put() - Release a transmit message
1237 *
1238 * @ph: Pointer to SCMI protocol handle
1239 * @xfer: message that was reserved by xfer_get_init
1240 */
xfer_put(const struct scmi_protocol_handle * ph,struct scmi_xfer * xfer)1241 static void xfer_put(const struct scmi_protocol_handle *ph,
1242 struct scmi_xfer *xfer)
1243 {
1244 const struct scmi_protocol_instance *pi = ph_to_pi(ph);
1245 struct scmi_info *info = handle_to_scmi_info(pi->handle);
1246
1247 __scmi_xfer_put(&info->tx_minfo, xfer);
1248 }
1249
scmi_xfer_done_no_timeout(struct scmi_chan_info * cinfo,struct scmi_xfer * xfer,ktime_t stop,bool * ooo)1250 static bool scmi_xfer_done_no_timeout(struct scmi_chan_info *cinfo,
1251 struct scmi_xfer *xfer, ktime_t stop,
1252 bool *ooo)
1253 {
1254 struct scmi_info *info = handle_to_scmi_info(cinfo->handle);
1255
1256 /*
1257 * Poll also on xfer->done so that polling can be forcibly terminated
1258 * in case of out-of-order receptions of delayed responses
1259 */
1260 return info->desc->ops->poll_done(cinfo, xfer) ||
1261 (*ooo = try_wait_for_completion(&xfer->done)) ||
1262 ktime_after(ktime_get(), stop);
1263 }
1264
scmi_wait_for_reply(struct device * dev,const struct scmi_desc * desc,struct scmi_chan_info * cinfo,struct scmi_xfer * xfer,unsigned int timeout_ms)1265 static int scmi_wait_for_reply(struct device *dev, const struct scmi_desc *desc,
1266 struct scmi_chan_info *cinfo,
1267 struct scmi_xfer *xfer, unsigned int timeout_ms)
1268 {
1269 int ret = 0;
1270 struct scmi_info *info = handle_to_scmi_info(cinfo->handle);
1271
1272 if (xfer->hdr.poll_completion) {
1273 /*
1274 * Real polling is needed only if transport has NOT declared
1275 * itself to support synchronous commands replies.
1276 */
1277 if (!desc->sync_cmds_completed_on_ret) {
1278 bool ooo = false;
1279
1280 /*
1281 * Poll on xfer using transport provided .poll_done();
1282 * assumes no completion interrupt was available.
1283 */
1284 ktime_t stop = ktime_add_ms(ktime_get(), timeout_ms);
1285
1286 spin_until_cond(scmi_xfer_done_no_timeout(cinfo, xfer,
1287 stop, &ooo));
1288 if (!ooo && !info->desc->ops->poll_done(cinfo, xfer)) {
1289 dev_err(dev,
1290 "timed out in resp(caller: %pS) - polling\n",
1291 (void *)_RET_IP_);
1292 ret = -ETIMEDOUT;
1293 scmi_inc_count(info->dbg->counters, XFERS_RESPONSE_POLLED_TIMEOUT);
1294 }
1295 }
1296
1297 if (!ret) {
1298 unsigned long flags;
1299
1300 /*
1301 * Do not fetch_response if an out-of-order delayed
1302 * response is being processed.
1303 */
1304 spin_lock_irqsave(&xfer->lock, flags);
1305 if (xfer->state == SCMI_XFER_SENT_OK) {
1306 desc->ops->fetch_response(cinfo, xfer);
1307 xfer->state = SCMI_XFER_RESP_OK;
1308 }
1309 spin_unlock_irqrestore(&xfer->lock, flags);
1310
1311 /* Trace polled replies. */
1312 trace_scmi_msg_dump(info->id, cinfo->id,
1313 xfer->hdr.protocol_id, xfer->hdr.id,
1314 !SCMI_XFER_IS_RAW(xfer) ?
1315 "RESP" : "resp",
1316 xfer->hdr.seq, xfer->hdr.status,
1317 xfer->rx.buf, xfer->rx.len);
1318 scmi_inc_count(info->dbg->counters, RESPONSE_POLLED_OK);
1319
1320 if (IS_ENABLED(CONFIG_ARM_SCMI_RAW_MODE_SUPPORT)) {
1321 scmi_raw_message_report(info->raw, xfer,
1322 SCMI_RAW_REPLY_QUEUE,
1323 cinfo->id);
1324 }
1325 }
1326 } else {
1327 /* And we wait for the response. */
1328 if (!wait_for_completion_timeout(&xfer->done,
1329 msecs_to_jiffies(timeout_ms))) {
1330 dev_err(dev, "timed out in resp(caller: %pS)\n",
1331 (void *)_RET_IP_);
1332 ret = -ETIMEDOUT;
1333 scmi_inc_count(info->dbg->counters, XFERS_RESPONSE_TIMEOUT);
1334 }
1335 }
1336
1337 return ret;
1338 }
1339
1340 /**
1341 * scmi_wait_for_message_response - An helper to group all the possible ways of
1342 * waiting for a synchronous message response.
1343 *
1344 * @cinfo: SCMI channel info
1345 * @xfer: Reference to the transfer being waited for.
1346 *
1347 * Chooses waiting strategy (sleep-waiting vs busy-waiting) depending on
1348 * configuration flags like xfer->hdr.poll_completion.
1349 *
1350 * Return: 0 on Success, error otherwise.
1351 */
scmi_wait_for_message_response(struct scmi_chan_info * cinfo,struct scmi_xfer * xfer)1352 static int scmi_wait_for_message_response(struct scmi_chan_info *cinfo,
1353 struct scmi_xfer *xfer)
1354 {
1355 struct scmi_info *info = handle_to_scmi_info(cinfo->handle);
1356 struct device *dev = info->dev;
1357
1358 trace_scmi_xfer_response_wait(xfer->transfer_id, xfer->hdr.id,
1359 xfer->hdr.protocol_id, xfer->hdr.seq,
1360 info->desc->max_rx_timeout_ms,
1361 xfer->hdr.poll_completion);
1362
1363 return scmi_wait_for_reply(dev, info->desc, cinfo, xfer,
1364 info->desc->max_rx_timeout_ms);
1365 }
1366
1367 /**
1368 * scmi_xfer_raw_wait_for_message_response - An helper to wait for a message
1369 * reply to an xfer raw request on a specific channel for the required timeout.
1370 *
1371 * @cinfo: SCMI channel info
1372 * @xfer: Reference to the transfer being waited for.
1373 * @timeout_ms: The maximum timeout in milliseconds
1374 *
1375 * Return: 0 on Success, error otherwise.
1376 */
scmi_xfer_raw_wait_for_message_response(struct scmi_chan_info * cinfo,struct scmi_xfer * xfer,unsigned int timeout_ms)1377 int scmi_xfer_raw_wait_for_message_response(struct scmi_chan_info *cinfo,
1378 struct scmi_xfer *xfer,
1379 unsigned int timeout_ms)
1380 {
1381 int ret;
1382 struct scmi_info *info = handle_to_scmi_info(cinfo->handle);
1383 struct device *dev = info->dev;
1384
1385 ret = scmi_wait_for_reply(dev, info->desc, cinfo, xfer, timeout_ms);
1386 if (ret)
1387 dev_dbg(dev, "timed out in RAW response - HDR:%08X\n",
1388 pack_scmi_header(&xfer->hdr));
1389
1390 return ret;
1391 }
1392
1393 /**
1394 * do_xfer() - Do one transfer
1395 *
1396 * @ph: Pointer to SCMI protocol handle
1397 * @xfer: Transfer to initiate and wait for response
1398 *
1399 * Return: -ETIMEDOUT in case of no response, if transmit error,
1400 * return corresponding error, else if all goes well,
1401 * return 0.
1402 */
do_xfer(const struct scmi_protocol_handle * ph,struct scmi_xfer * xfer)1403 static int do_xfer(const struct scmi_protocol_handle *ph,
1404 struct scmi_xfer *xfer)
1405 {
1406 int ret;
1407 const struct scmi_protocol_instance *pi = ph_to_pi(ph);
1408 struct scmi_info *info = handle_to_scmi_info(pi->handle);
1409 struct device *dev = info->dev;
1410 struct scmi_chan_info *cinfo;
1411
1412 /* Check for polling request on custom command xfers at first */
1413 if (xfer->hdr.poll_completion &&
1414 !is_transport_polling_capable(info->desc)) {
1415 dev_warn_once(dev,
1416 "Polling mode is not supported by transport.\n");
1417 scmi_inc_count(info->dbg->counters, SENT_FAIL_POLLING_UNSUPPORTED);
1418 return -EINVAL;
1419 }
1420
1421 cinfo = idr_find(&info->tx_idr, pi->proto->id);
1422 if (unlikely(!cinfo)) {
1423 scmi_inc_count(info->dbg->counters, SENT_FAIL_CHANNEL_NOT_FOUND);
1424 return -EINVAL;
1425 }
1426 /* True ONLY if also supported by transport. */
1427 if (is_polling_enabled(cinfo, info->desc))
1428 xfer->hdr.poll_completion = true;
1429
1430 /*
1431 * Initialise protocol id now from protocol handle to avoid it being
1432 * overridden by mistake (or malice) by the protocol code mangling with
1433 * the scmi_xfer structure prior to this.
1434 */
1435 xfer->hdr.protocol_id = pi->proto->id;
1436 reinit_completion(&xfer->done);
1437
1438 trace_scmi_xfer_begin(xfer->transfer_id, xfer->hdr.id,
1439 xfer->hdr.protocol_id, xfer->hdr.seq,
1440 xfer->hdr.poll_completion);
1441
1442 /* Clear any stale status */
1443 xfer->hdr.status = SCMI_SUCCESS;
1444 xfer->state = SCMI_XFER_SENT_OK;
1445 /*
1446 * Even though spinlocking is not needed here since no race is possible
1447 * on xfer->state due to the monotonically increasing tokens allocation,
1448 * we must anyway ensure xfer->state initialization is not re-ordered
1449 * after the .send_message() to be sure that on the RX path an early
1450 * ISR calling scmi_rx_callback() cannot see an old stale xfer->state.
1451 */
1452 smp_mb();
1453
1454 ret = info->desc->ops->send_message(cinfo, xfer);
1455 if (ret < 0) {
1456 dev_dbg(dev, "Failed to send message %d\n", ret);
1457 scmi_inc_count(info->dbg->counters, SENT_FAIL);
1458 return ret;
1459 }
1460
1461 trace_scmi_msg_dump(info->id, cinfo->id, xfer->hdr.protocol_id,
1462 xfer->hdr.id, "CMND", xfer->hdr.seq,
1463 xfer->hdr.status, xfer->tx.buf, xfer->tx.len);
1464 scmi_inc_count(info->dbg->counters, SENT_OK);
1465
1466 ret = scmi_wait_for_message_response(cinfo, xfer);
1467 if (!ret && xfer->hdr.status) {
1468 ret = scmi_to_linux_errno(xfer->hdr.status);
1469 scmi_inc_count(info->dbg->counters, ERR_PROTOCOL);
1470 }
1471
1472 if (info->desc->ops->mark_txdone)
1473 info->desc->ops->mark_txdone(cinfo, ret, xfer);
1474
1475 trace_scmi_xfer_end(xfer->transfer_id, xfer->hdr.id,
1476 xfer->hdr.protocol_id, xfer->hdr.seq, ret);
1477
1478 return ret;
1479 }
1480
reset_rx_to_maxsz(const struct scmi_protocol_handle * ph,struct scmi_xfer * xfer)1481 static void reset_rx_to_maxsz(const struct scmi_protocol_handle *ph,
1482 struct scmi_xfer *xfer)
1483 {
1484 const struct scmi_protocol_instance *pi = ph_to_pi(ph);
1485 struct scmi_info *info = handle_to_scmi_info(pi->handle);
1486
1487 xfer->rx.len = info->desc->max_msg_size;
1488 }
1489
1490 /**
1491 * do_xfer_with_response() - Do one transfer and wait until the delayed
1492 * response is received
1493 *
1494 * @ph: Pointer to SCMI protocol handle
1495 * @xfer: Transfer to initiate and wait for response
1496 *
1497 * Using asynchronous commands in atomic/polling mode should be avoided since
1498 * it could cause long busy-waiting here, so ignore polling for the delayed
1499 * response and WARN if it was requested for this command transaction since
1500 * upper layers should refrain from issuing such kind of requests.
1501 *
1502 * The only other option would have been to refrain from using any asynchronous
1503 * command even if made available, when an atomic transport is detected, and
1504 * instead forcibly use the synchronous version (thing that can be easily
1505 * attained at the protocol layer), but this would also have led to longer
1506 * stalls of the channel for synchronous commands and possibly timeouts.
1507 * (in other words there is usually a good reason if a platform provides an
1508 * asynchronous version of a command and we should prefer to use it...just not
1509 * when using atomic/polling mode)
1510 *
1511 * Return: -ETIMEDOUT in case of no delayed response, if transmit error,
1512 * return corresponding error, else if all goes well, return 0.
1513 */
do_xfer_with_response(const struct scmi_protocol_handle * ph,struct scmi_xfer * xfer)1514 static int do_xfer_with_response(const struct scmi_protocol_handle *ph,
1515 struct scmi_xfer *xfer)
1516 {
1517 int ret, timeout = msecs_to_jiffies(SCMI_MAX_RESPONSE_TIMEOUT);
1518 DECLARE_COMPLETION_ONSTACK(async_response);
1519
1520 xfer->async_done = &async_response;
1521
1522 /*
1523 * Delayed responses should not be polled, so an async command should
1524 * not have been used when requiring an atomic/poll context; WARN and
1525 * perform instead a sleeping wait.
1526 * (Note Async + IgnoreDelayedResponses are sent via do_xfer)
1527 */
1528 WARN_ON_ONCE(xfer->hdr.poll_completion);
1529
1530 ret = do_xfer(ph, xfer);
1531 if (!ret) {
1532 if (!wait_for_completion_timeout(xfer->async_done, timeout)) {
1533 dev_err(ph->dev,
1534 "timed out in delayed resp(caller: %pS)\n",
1535 (void *)_RET_IP_);
1536 ret = -ETIMEDOUT;
1537 } else if (xfer->hdr.status) {
1538 ret = scmi_to_linux_errno(xfer->hdr.status);
1539 }
1540 }
1541
1542 xfer->async_done = NULL;
1543 return ret;
1544 }
1545
1546 /**
1547 * xfer_get_init() - Allocate and initialise one message for transmit
1548 *
1549 * @ph: Pointer to SCMI protocol handle
1550 * @msg_id: Message identifier
1551 * @tx_size: transmit message size
1552 * @rx_size: receive message size
1553 * @p: pointer to the allocated and initialised message
1554 *
1555 * This function allocates the message using @scmi_xfer_get and
1556 * initialise the header.
1557 *
1558 * Return: 0 if all went fine with @p pointing to message, else
1559 * corresponding error.
1560 */
xfer_get_init(const struct scmi_protocol_handle * ph,u8 msg_id,size_t tx_size,size_t rx_size,struct scmi_xfer ** p)1561 static int xfer_get_init(const struct scmi_protocol_handle *ph,
1562 u8 msg_id, size_t tx_size, size_t rx_size,
1563 struct scmi_xfer **p)
1564 {
1565 int ret;
1566 struct scmi_xfer *xfer;
1567 const struct scmi_protocol_instance *pi = ph_to_pi(ph);
1568 struct scmi_info *info = handle_to_scmi_info(pi->handle);
1569 struct scmi_xfers_info *minfo = &info->tx_minfo;
1570 struct device *dev = info->dev;
1571
1572 /* Ensure we have sane transfer sizes */
1573 if (rx_size > info->desc->max_msg_size ||
1574 tx_size > info->desc->max_msg_size)
1575 return -ERANGE;
1576
1577 xfer = scmi_xfer_get(pi->handle, minfo);
1578 if (IS_ERR(xfer)) {
1579 ret = PTR_ERR(xfer);
1580 dev_err(dev, "failed to get free message slot(%d)\n", ret);
1581 return ret;
1582 }
1583
1584 /* Pick a sequence number and register this xfer as in-flight */
1585 ret = scmi_xfer_pending_set(xfer, minfo);
1586 if (ret) {
1587 dev_err(pi->handle->dev,
1588 "Failed to get monotonic token %d\n", ret);
1589 __scmi_xfer_put(minfo, xfer);
1590 return ret;
1591 }
1592
1593 xfer->tx.len = tx_size;
1594 xfer->rx.len = rx_size ? : info->desc->max_msg_size;
1595 xfer->hdr.type = MSG_TYPE_COMMAND;
1596 xfer->hdr.id = msg_id;
1597 xfer->hdr.poll_completion = false;
1598
1599 *p = xfer;
1600
1601 return 0;
1602 }
1603
1604 /**
1605 * version_get() - command to get the revision of the SCMI entity
1606 *
1607 * @ph: Pointer to SCMI protocol handle
1608 * @version: Holds returned version of protocol.
1609 *
1610 * Updates the SCMI information in the internal data structure.
1611 *
1612 * Return: 0 if all went fine, else return appropriate error.
1613 */
version_get(const struct scmi_protocol_handle * ph,u32 * version)1614 static int version_get(const struct scmi_protocol_handle *ph, u32 *version)
1615 {
1616 int ret;
1617 __le32 *rev_info;
1618 struct scmi_xfer *t;
1619
1620 ret = xfer_get_init(ph, PROTOCOL_VERSION, 0, sizeof(*version), &t);
1621 if (ret)
1622 return ret;
1623
1624 ret = do_xfer(ph, t);
1625 if (!ret) {
1626 rev_info = t->rx.buf;
1627 *version = le32_to_cpu(*rev_info);
1628 }
1629
1630 xfer_put(ph, t);
1631 return ret;
1632 }
1633
1634 /**
1635 * scmi_set_protocol_priv - Set protocol specific data at init time
1636 *
1637 * @ph: A reference to the protocol handle.
1638 * @priv: The private data to set.
1639 * @version: The detected protocol version for the core to register.
1640 *
1641 * Return: 0 on Success
1642 */
scmi_set_protocol_priv(const struct scmi_protocol_handle * ph,void * priv,u32 version)1643 static int scmi_set_protocol_priv(const struct scmi_protocol_handle *ph,
1644 void *priv, u32 version)
1645 {
1646 struct scmi_protocol_instance *pi = ph_to_pi(ph);
1647
1648 pi->priv = priv;
1649 pi->version = version;
1650
1651 return 0;
1652 }
1653
1654 /**
1655 * scmi_get_protocol_priv - Set protocol specific data at init time
1656 *
1657 * @ph: A reference to the protocol handle.
1658 *
1659 * Return: Protocol private data if any was set.
1660 */
scmi_get_protocol_priv(const struct scmi_protocol_handle * ph)1661 static void *scmi_get_protocol_priv(const struct scmi_protocol_handle *ph)
1662 {
1663 const struct scmi_protocol_instance *pi = ph_to_pi(ph);
1664
1665 return pi->priv;
1666 }
1667
1668 static const struct scmi_xfer_ops xfer_ops = {
1669 .version_get = version_get,
1670 .xfer_get_init = xfer_get_init,
1671 .reset_rx_to_maxsz = reset_rx_to_maxsz,
1672 .do_xfer = do_xfer,
1673 .do_xfer_with_response = do_xfer_with_response,
1674 .xfer_put = xfer_put,
1675 };
1676
1677 struct scmi_msg_resp_domain_name_get {
1678 __le32 flags;
1679 u8 name[SCMI_MAX_STR_SIZE];
1680 };
1681
1682 /**
1683 * scmi_common_extended_name_get - Common helper to get extended resources name
1684 * @ph: A protocol handle reference.
1685 * @cmd_id: The specific command ID to use.
1686 * @res_id: The specific resource ID to use.
1687 * @flags: A pointer to specific flags to use, if any.
1688 * @name: A pointer to the preallocated area where the retrieved name will be
1689 * stored as a NULL terminated string.
1690 * @len: The len in bytes of the @name char array.
1691 *
1692 * Return: 0 on Succcess
1693 */
scmi_common_extended_name_get(const struct scmi_protocol_handle * ph,u8 cmd_id,u32 res_id,u32 * flags,char * name,size_t len)1694 static int scmi_common_extended_name_get(const struct scmi_protocol_handle *ph,
1695 u8 cmd_id, u32 res_id, u32 *flags,
1696 char *name, size_t len)
1697 {
1698 int ret;
1699 size_t txlen;
1700 struct scmi_xfer *t;
1701 struct scmi_msg_resp_domain_name_get *resp;
1702
1703 txlen = !flags ? sizeof(res_id) : sizeof(res_id) + sizeof(*flags);
1704 ret = ph->xops->xfer_get_init(ph, cmd_id, txlen, sizeof(*resp), &t);
1705 if (ret)
1706 goto out;
1707
1708 put_unaligned_le32(res_id, t->tx.buf);
1709 if (flags)
1710 put_unaligned_le32(*flags, t->tx.buf + sizeof(res_id));
1711 resp = t->rx.buf;
1712
1713 ret = ph->xops->do_xfer(ph, t);
1714 if (!ret)
1715 strscpy(name, resp->name, len);
1716
1717 ph->xops->xfer_put(ph, t);
1718 out:
1719 if (ret)
1720 dev_warn(ph->dev,
1721 "Failed to get extended name - id:%u (ret:%d). Using %s\n",
1722 res_id, ret, name);
1723 return ret;
1724 }
1725
1726 /**
1727 * scmi_common_get_max_msg_size - Get maximum message size
1728 * @ph: A protocol handle reference.
1729 *
1730 * Return: Maximum message size for the current protocol.
1731 */
scmi_common_get_max_msg_size(const struct scmi_protocol_handle * ph)1732 static int scmi_common_get_max_msg_size(const struct scmi_protocol_handle *ph)
1733 {
1734 const struct scmi_protocol_instance *pi = ph_to_pi(ph);
1735 struct scmi_info *info = handle_to_scmi_info(pi->handle);
1736
1737 return info->desc->max_msg_size;
1738 }
1739
1740 /**
1741 * struct scmi_iterator - Iterator descriptor
1742 * @msg: A reference to the message TX buffer; filled by @prepare_message with
1743 * a proper custom command payload for each multi-part command request.
1744 * @resp: A reference to the response RX buffer; used by @update_state and
1745 * @process_response to parse the multi-part replies.
1746 * @t: A reference to the underlying xfer initialized and used transparently by
1747 * the iterator internal routines.
1748 * @ph: A reference to the associated protocol handle to be used.
1749 * @ops: A reference to the custom provided iterator operations.
1750 * @state: The current iterator state; used and updated in turn by the iterators
1751 * internal routines and by the caller-provided @scmi_iterator_ops.
1752 * @priv: A reference to optional private data as provided by the caller and
1753 * passed back to the @@scmi_iterator_ops.
1754 */
1755 struct scmi_iterator {
1756 void *msg;
1757 void *resp;
1758 struct scmi_xfer *t;
1759 const struct scmi_protocol_handle *ph;
1760 struct scmi_iterator_ops *ops;
1761 struct scmi_iterator_state state;
1762 void *priv;
1763 };
1764
scmi_iterator_init(const struct scmi_protocol_handle * ph,struct scmi_iterator_ops * ops,unsigned int max_resources,u8 msg_id,size_t tx_size,void * priv)1765 static void *scmi_iterator_init(const struct scmi_protocol_handle *ph,
1766 struct scmi_iterator_ops *ops,
1767 unsigned int max_resources, u8 msg_id,
1768 size_t tx_size, void *priv)
1769 {
1770 int ret;
1771 struct scmi_iterator *i;
1772
1773 i = devm_kzalloc(ph->dev, sizeof(*i), GFP_KERNEL);
1774 if (!i)
1775 return ERR_PTR(-ENOMEM);
1776
1777 i->ph = ph;
1778 i->ops = ops;
1779 i->priv = priv;
1780
1781 ret = ph->xops->xfer_get_init(ph, msg_id, tx_size, 0, &i->t);
1782 if (ret) {
1783 devm_kfree(ph->dev, i);
1784 return ERR_PTR(ret);
1785 }
1786
1787 i->state.max_resources = max_resources;
1788 i->msg = i->t->tx.buf;
1789 i->resp = i->t->rx.buf;
1790
1791 return i;
1792 }
1793
scmi_iterator_run(void * iter)1794 static int scmi_iterator_run(void *iter)
1795 {
1796 int ret = -EINVAL;
1797 struct scmi_iterator_ops *iops;
1798 const struct scmi_protocol_handle *ph;
1799 struct scmi_iterator_state *st;
1800 struct scmi_iterator *i = iter;
1801
1802 if (!i || !i->ops || !i->ph)
1803 return ret;
1804
1805 iops = i->ops;
1806 ph = i->ph;
1807 st = &i->state;
1808
1809 do {
1810 iops->prepare_message(i->msg, st->desc_index, i->priv);
1811 ret = ph->xops->do_xfer(ph, i->t);
1812 if (ret)
1813 break;
1814
1815 st->rx_len = i->t->rx.len;
1816 ret = iops->update_state(st, i->resp, i->priv);
1817 if (ret)
1818 break;
1819
1820 if (st->num_returned > st->max_resources - st->desc_index) {
1821 dev_err(ph->dev,
1822 "No. of resources can't exceed %d\n",
1823 st->max_resources);
1824 ret = -EINVAL;
1825 break;
1826 }
1827
1828 for (st->loop_idx = 0; st->loop_idx < st->num_returned;
1829 st->loop_idx++) {
1830 ret = iops->process_response(ph, i->resp, st, i->priv);
1831 if (ret)
1832 goto out;
1833 }
1834
1835 st->desc_index += st->num_returned;
1836 ph->xops->reset_rx_to_maxsz(ph, i->t);
1837 /*
1838 * check for both returned and remaining to avoid infinite
1839 * loop due to buggy firmware
1840 */
1841 } while (st->num_returned && st->num_remaining);
1842
1843 out:
1844 /* Finalize and destroy iterator */
1845 ph->xops->xfer_put(ph, i->t);
1846 devm_kfree(ph->dev, i);
1847
1848 return ret;
1849 }
1850
1851 struct scmi_msg_get_fc_info {
1852 __le32 domain;
1853 __le32 message_id;
1854 };
1855
1856 struct scmi_msg_resp_desc_fc {
1857 __le32 attr;
1858 #define SUPPORTS_DOORBELL(x) ((x) & BIT(0))
1859 #define DOORBELL_REG_WIDTH(x) FIELD_GET(GENMASK(2, 1), (x))
1860 __le32 rate_limit;
1861 __le32 chan_addr_low;
1862 __le32 chan_addr_high;
1863 __le32 chan_size;
1864 __le32 db_addr_low;
1865 __le32 db_addr_high;
1866 __le32 db_set_lmask;
1867 __le32 db_set_hmask;
1868 __le32 db_preserve_lmask;
1869 __le32 db_preserve_hmask;
1870 };
1871
1872 static void
scmi_common_fastchannel_init(const struct scmi_protocol_handle * ph,u8 describe_id,u32 message_id,u32 valid_size,u32 domain,void __iomem ** p_addr,struct scmi_fc_db_info ** p_db,u32 * rate_limit)1873 scmi_common_fastchannel_init(const struct scmi_protocol_handle *ph,
1874 u8 describe_id, u32 message_id, u32 valid_size,
1875 u32 domain, void __iomem **p_addr,
1876 struct scmi_fc_db_info **p_db, u32 *rate_limit)
1877 {
1878 int ret;
1879 u32 flags;
1880 u64 phys_addr;
1881 u8 size;
1882 void __iomem *addr;
1883 struct scmi_xfer *t;
1884 struct scmi_fc_db_info *db = NULL;
1885 struct scmi_msg_get_fc_info *info;
1886 struct scmi_msg_resp_desc_fc *resp;
1887 const struct scmi_protocol_instance *pi = ph_to_pi(ph);
1888
1889 if (!p_addr) {
1890 ret = -EINVAL;
1891 goto err_out;
1892 }
1893
1894 ret = ph->xops->xfer_get_init(ph, describe_id,
1895 sizeof(*info), sizeof(*resp), &t);
1896 if (ret)
1897 goto err_out;
1898
1899 info = t->tx.buf;
1900 info->domain = cpu_to_le32(domain);
1901 info->message_id = cpu_to_le32(message_id);
1902
1903 /*
1904 * Bail out on error leaving fc_info addresses zeroed; this includes
1905 * the case in which the requested domain/message_id does NOT support
1906 * fastchannels at all.
1907 */
1908 ret = ph->xops->do_xfer(ph, t);
1909 if (ret)
1910 goto err_xfer;
1911
1912 resp = t->rx.buf;
1913 flags = le32_to_cpu(resp->attr);
1914 size = le32_to_cpu(resp->chan_size);
1915 if (size != valid_size) {
1916 ret = -EINVAL;
1917 goto err_xfer;
1918 }
1919
1920 if (rate_limit)
1921 *rate_limit = le32_to_cpu(resp->rate_limit) & GENMASK(19, 0);
1922
1923 phys_addr = le32_to_cpu(resp->chan_addr_low);
1924 phys_addr |= (u64)le32_to_cpu(resp->chan_addr_high) << 32;
1925 addr = devm_ioremap(ph->dev, phys_addr, size);
1926 if (!addr) {
1927 ret = -EADDRNOTAVAIL;
1928 goto err_xfer;
1929 }
1930
1931 *p_addr = addr;
1932
1933 if (p_db && SUPPORTS_DOORBELL(flags)) {
1934 db = devm_kzalloc(ph->dev, sizeof(*db), GFP_KERNEL);
1935 if (!db) {
1936 ret = -ENOMEM;
1937 goto err_db;
1938 }
1939
1940 size = 1 << DOORBELL_REG_WIDTH(flags);
1941 phys_addr = le32_to_cpu(resp->db_addr_low);
1942 phys_addr |= (u64)le32_to_cpu(resp->db_addr_high) << 32;
1943 addr = devm_ioremap(ph->dev, phys_addr, size);
1944 if (!addr) {
1945 ret = -EADDRNOTAVAIL;
1946 goto err_db_mem;
1947 }
1948
1949 db->addr = addr;
1950 db->width = size;
1951 db->set = le32_to_cpu(resp->db_set_lmask);
1952 db->set |= (u64)le32_to_cpu(resp->db_set_hmask) << 32;
1953 db->mask = le32_to_cpu(resp->db_preserve_lmask);
1954 db->mask |= (u64)le32_to_cpu(resp->db_preserve_hmask) << 32;
1955
1956 *p_db = db;
1957 }
1958
1959 ph->xops->xfer_put(ph, t);
1960
1961 dev_dbg(ph->dev,
1962 "Using valid FC for protocol %X [MSG_ID:%u / RES_ID:%u]\n",
1963 pi->proto->id, message_id, domain);
1964
1965 return;
1966
1967 err_db_mem:
1968 devm_kfree(ph->dev, db);
1969
1970 err_db:
1971 *p_addr = NULL;
1972
1973 err_xfer:
1974 ph->xops->xfer_put(ph, t);
1975
1976 err_out:
1977 dev_warn(ph->dev,
1978 "Failed to get FC for protocol %X [MSG_ID:%u / RES_ID:%u] - ret:%d. Using regular messaging.\n",
1979 pi->proto->id, message_id, domain, ret);
1980 }
1981
1982 #define SCMI_PROTO_FC_RING_DB(w) \
1983 do { \
1984 u##w val = 0; \
1985 \
1986 if (db->mask) \
1987 val = ioread##w(db->addr) & db->mask; \
1988 iowrite##w((u##w)db->set | val, db->addr); \
1989 } while (0)
1990
scmi_common_fastchannel_db_ring(struct scmi_fc_db_info * db)1991 static void scmi_common_fastchannel_db_ring(struct scmi_fc_db_info *db)
1992 {
1993 if (!db || !db->addr)
1994 return;
1995
1996 if (db->width == 1)
1997 SCMI_PROTO_FC_RING_DB(8);
1998 else if (db->width == 2)
1999 SCMI_PROTO_FC_RING_DB(16);
2000 else if (db->width == 4)
2001 SCMI_PROTO_FC_RING_DB(32);
2002 else /* db->width == 8 */
2003 SCMI_PROTO_FC_RING_DB(64);
2004 }
2005
2006 /**
2007 * scmi_protocol_msg_check - Check protocol message attributes
2008 *
2009 * @ph: A reference to the protocol handle.
2010 * @message_id: The ID of the message to check.
2011 * @attributes: A parameter to optionally return the retrieved message
2012 * attributes, in case of Success.
2013 *
2014 * An helper to check protocol message attributes for a specific protocol
2015 * and message pair.
2016 *
2017 * Return: 0 on SUCCESS
2018 */
scmi_protocol_msg_check(const struct scmi_protocol_handle * ph,u32 message_id,u32 * attributes)2019 static int scmi_protocol_msg_check(const struct scmi_protocol_handle *ph,
2020 u32 message_id, u32 *attributes)
2021 {
2022 int ret;
2023 struct scmi_xfer *t;
2024
2025 ret = xfer_get_init(ph, PROTOCOL_MESSAGE_ATTRIBUTES,
2026 sizeof(__le32), 0, &t);
2027 if (ret)
2028 return ret;
2029
2030 put_unaligned_le32(message_id, t->tx.buf);
2031 ret = do_xfer(ph, t);
2032 if (!ret && attributes)
2033 *attributes = get_unaligned_le32(t->rx.buf);
2034 xfer_put(ph, t);
2035
2036 return ret;
2037 }
2038
2039 static const struct scmi_proto_helpers_ops helpers_ops = {
2040 .extended_name_get = scmi_common_extended_name_get,
2041 .get_max_msg_size = scmi_common_get_max_msg_size,
2042 .iter_response_init = scmi_iterator_init,
2043 .iter_response_run = scmi_iterator_run,
2044 .protocol_msg_check = scmi_protocol_msg_check,
2045 .fastchannel_init = scmi_common_fastchannel_init,
2046 .fastchannel_db_ring = scmi_common_fastchannel_db_ring,
2047 };
2048
2049 /**
2050 * scmi_revision_area_get - Retrieve version memory area.
2051 *
2052 * @ph: A reference to the protocol handle.
2053 *
2054 * A helper to grab the version memory area reference during SCMI Base protocol
2055 * initialization.
2056 *
2057 * Return: A reference to the version memory area associated to the SCMI
2058 * instance underlying this protocol handle.
2059 */
2060 struct scmi_revision_info *
scmi_revision_area_get(const struct scmi_protocol_handle * ph)2061 scmi_revision_area_get(const struct scmi_protocol_handle *ph)
2062 {
2063 const struct scmi_protocol_instance *pi = ph_to_pi(ph);
2064
2065 return pi->handle->version;
2066 }
2067
2068 /**
2069 * scmi_protocol_version_negotiate - Negotiate protocol version
2070 *
2071 * @ph: A reference to the protocol handle.
2072 *
2073 * An helper to negotiate a protocol version different from the latest
2074 * advertised as supported from the platform: on Success backward
2075 * compatibility is assured by the platform.
2076 *
2077 * Return: 0 on Success
2078 */
scmi_protocol_version_negotiate(struct scmi_protocol_handle * ph)2079 static int scmi_protocol_version_negotiate(struct scmi_protocol_handle *ph)
2080 {
2081 int ret;
2082 struct scmi_xfer *t;
2083 struct scmi_protocol_instance *pi = ph_to_pi(ph);
2084
2085 /* At first check if NEGOTIATE_PROTOCOL_VERSION is supported ... */
2086 ret = scmi_protocol_msg_check(ph, NEGOTIATE_PROTOCOL_VERSION, NULL);
2087 if (ret)
2088 return ret;
2089
2090 /* ... then attempt protocol version negotiation */
2091 ret = xfer_get_init(ph, NEGOTIATE_PROTOCOL_VERSION,
2092 sizeof(__le32), 0, &t);
2093 if (ret)
2094 return ret;
2095
2096 put_unaligned_le32(pi->proto->supported_version, t->tx.buf);
2097 ret = do_xfer(ph, t);
2098 if (!ret)
2099 pi->negotiated_version = pi->proto->supported_version;
2100
2101 xfer_put(ph, t);
2102
2103 return ret;
2104 }
2105
2106 /**
2107 * scmi_alloc_init_protocol_instance - Allocate and initialize a protocol
2108 * instance descriptor.
2109 * @info: The reference to the related SCMI instance.
2110 * @proto: The protocol descriptor.
2111 *
2112 * Allocate a new protocol instance descriptor, using the provided @proto
2113 * description, against the specified SCMI instance @info, and initialize it;
2114 * all resources management is handled via a dedicated per-protocol devres
2115 * group.
2116 *
2117 * Context: Assumes to be called with @protocols_mtx already acquired.
2118 * Return: A reference to a freshly allocated and initialized protocol instance
2119 * or ERR_PTR on failure. On failure the @proto reference is at first
2120 * put using @scmi_protocol_put() before releasing all the devres group.
2121 */
2122 static struct scmi_protocol_instance *
scmi_alloc_init_protocol_instance(struct scmi_info * info,const struct scmi_protocol * proto)2123 scmi_alloc_init_protocol_instance(struct scmi_info *info,
2124 const struct scmi_protocol *proto)
2125 {
2126 int ret = -ENOMEM;
2127 void *gid;
2128 struct scmi_protocol_instance *pi;
2129 const struct scmi_handle *handle = &info->handle;
2130
2131 /* Protocol specific devres group */
2132 gid = devres_open_group(handle->dev, NULL, GFP_KERNEL);
2133 if (!gid) {
2134 scmi_protocol_put(proto);
2135 goto out;
2136 }
2137
2138 pi = devm_kzalloc(handle->dev, sizeof(*pi), GFP_KERNEL);
2139 if (!pi)
2140 goto clean;
2141
2142 pi->gid = gid;
2143 pi->proto = proto;
2144 pi->handle = handle;
2145 pi->ph.dev = handle->dev;
2146 pi->ph.xops = &xfer_ops;
2147 pi->ph.hops = &helpers_ops;
2148 pi->ph.set_priv = scmi_set_protocol_priv;
2149 pi->ph.get_priv = scmi_get_protocol_priv;
2150 refcount_set(&pi->users, 1);
2151 /* proto->init is assured NON NULL by scmi_protocol_register */
2152 ret = pi->proto->instance_init(&pi->ph);
2153 if (ret)
2154 goto clean;
2155
2156 ret = idr_alloc(&info->protocols, pi, proto->id, proto->id + 1,
2157 GFP_KERNEL);
2158 if (ret != proto->id)
2159 goto clean;
2160
2161 /*
2162 * Warn but ignore events registration errors since we do not want
2163 * to skip whole protocols if their notifications are messed up.
2164 */
2165 if (pi->proto->events) {
2166 ret = scmi_register_protocol_events(handle, pi->proto->id,
2167 &pi->ph,
2168 pi->proto->events);
2169 if (ret)
2170 dev_warn(handle->dev,
2171 "Protocol:%X - Events Registration Failed - err:%d\n",
2172 pi->proto->id, ret);
2173 }
2174
2175 devres_close_group(handle->dev, pi->gid);
2176 dev_dbg(handle->dev, "Initialized protocol: 0x%X\n", pi->proto->id);
2177
2178 if (pi->version > proto->supported_version) {
2179 ret = scmi_protocol_version_negotiate(&pi->ph);
2180 if (!ret) {
2181 dev_info(handle->dev,
2182 "Protocol 0x%X successfully negotiated version 0x%X\n",
2183 proto->id, pi->negotiated_version);
2184 } else {
2185 dev_warn(handle->dev,
2186 "Detected UNSUPPORTED higher version 0x%X for protocol 0x%X.\n",
2187 pi->version, pi->proto->id);
2188 dev_warn(handle->dev,
2189 "Trying version 0x%X. Backward compatibility is NOT assured.\n",
2190 pi->proto->supported_version);
2191 }
2192 }
2193
2194 return pi;
2195
2196 clean:
2197 /* Take care to put the protocol module's owner before releasing all */
2198 scmi_protocol_put(proto);
2199 devres_release_group(handle->dev, gid);
2200 out:
2201 return ERR_PTR(ret);
2202 }
2203
2204 /**
2205 * scmi_get_protocol_instance - Protocol initialization helper.
2206 * @handle: A reference to the SCMI platform instance.
2207 * @protocol_id: The protocol being requested.
2208 *
2209 * In case the required protocol has never been requested before for this
2210 * instance, allocate and initialize all the needed structures while handling
2211 * resource allocation with a dedicated per-protocol devres subgroup.
2212 *
2213 * Return: A reference to an initialized protocol instance or error on failure:
2214 * in particular returns -EPROBE_DEFER when the desired protocol could
2215 * NOT be found.
2216 */
2217 static struct scmi_protocol_instance * __must_check
scmi_get_protocol_instance(const struct scmi_handle * handle,u8 protocol_id)2218 scmi_get_protocol_instance(const struct scmi_handle *handle, u8 protocol_id)
2219 {
2220 struct scmi_protocol_instance *pi;
2221 struct scmi_info *info = handle_to_scmi_info(handle);
2222
2223 mutex_lock(&info->protocols_mtx);
2224 pi = idr_find(&info->protocols, protocol_id);
2225
2226 if (pi) {
2227 refcount_inc(&pi->users);
2228 } else {
2229 const struct scmi_protocol *proto;
2230
2231 /* Fails if protocol not registered on bus */
2232 proto = scmi_protocol_get(protocol_id, &info->version);
2233 if (proto)
2234 pi = scmi_alloc_init_protocol_instance(info, proto);
2235 else
2236 pi = ERR_PTR(-EPROBE_DEFER);
2237 }
2238 mutex_unlock(&info->protocols_mtx);
2239
2240 return pi;
2241 }
2242
2243 /**
2244 * scmi_protocol_acquire - Protocol acquire
2245 * @handle: A reference to the SCMI platform instance.
2246 * @protocol_id: The protocol being requested.
2247 *
2248 * Register a new user for the requested protocol on the specified SCMI
2249 * platform instance, possibly triggering its initialization on first user.
2250 *
2251 * Return: 0 if protocol was acquired successfully.
2252 */
scmi_protocol_acquire(const struct scmi_handle * handle,u8 protocol_id)2253 int scmi_protocol_acquire(const struct scmi_handle *handle, u8 protocol_id)
2254 {
2255 return PTR_ERR_OR_ZERO(scmi_get_protocol_instance(handle, protocol_id));
2256 }
2257
2258 /**
2259 * scmi_protocol_release - Protocol de-initialization helper.
2260 * @handle: A reference to the SCMI platform instance.
2261 * @protocol_id: The protocol being requested.
2262 *
2263 * Remove one user for the specified protocol and triggers de-initialization
2264 * and resources de-allocation once the last user has gone.
2265 */
scmi_protocol_release(const struct scmi_handle * handle,u8 protocol_id)2266 void scmi_protocol_release(const struct scmi_handle *handle, u8 protocol_id)
2267 {
2268 struct scmi_info *info = handle_to_scmi_info(handle);
2269 struct scmi_protocol_instance *pi;
2270
2271 mutex_lock(&info->protocols_mtx);
2272 pi = idr_find(&info->protocols, protocol_id);
2273 if (WARN_ON(!pi))
2274 goto out;
2275
2276 if (refcount_dec_and_test(&pi->users)) {
2277 void *gid = pi->gid;
2278
2279 if (pi->proto->events)
2280 scmi_deregister_protocol_events(handle, protocol_id);
2281
2282 if (pi->proto->instance_deinit)
2283 pi->proto->instance_deinit(&pi->ph);
2284
2285 idr_remove(&info->protocols, protocol_id);
2286
2287 scmi_protocol_put(pi->proto);
2288
2289 devres_release_group(handle->dev, gid);
2290 dev_dbg(handle->dev, "De-Initialized protocol: 0x%X\n",
2291 protocol_id);
2292 }
2293
2294 out:
2295 mutex_unlock(&info->protocols_mtx);
2296 }
2297
scmi_setup_protocol_implemented(const struct scmi_protocol_handle * ph,u8 * prot_imp)2298 void scmi_setup_protocol_implemented(const struct scmi_protocol_handle *ph,
2299 u8 *prot_imp)
2300 {
2301 const struct scmi_protocol_instance *pi = ph_to_pi(ph);
2302 struct scmi_info *info = handle_to_scmi_info(pi->handle);
2303
2304 info->protocols_imp = prot_imp;
2305 }
2306
2307 static bool
scmi_is_protocol_implemented(const struct scmi_handle * handle,u8 prot_id)2308 scmi_is_protocol_implemented(const struct scmi_handle *handle, u8 prot_id)
2309 {
2310 int i;
2311 struct scmi_info *info = handle_to_scmi_info(handle);
2312 struct scmi_revision_info *rev = handle->version;
2313
2314 if (!info->protocols_imp)
2315 return false;
2316
2317 for (i = 0; i < rev->num_protocols; i++)
2318 if (info->protocols_imp[i] == prot_id)
2319 return true;
2320 return false;
2321 }
2322
2323 struct scmi_protocol_devres {
2324 const struct scmi_handle *handle;
2325 u8 protocol_id;
2326 };
2327
scmi_devm_release_protocol(struct device * dev,void * res)2328 static void scmi_devm_release_protocol(struct device *dev, void *res)
2329 {
2330 struct scmi_protocol_devres *dres = res;
2331
2332 scmi_protocol_release(dres->handle, dres->protocol_id);
2333 }
2334
2335 static struct scmi_protocol_instance __must_check *
scmi_devres_protocol_instance_get(struct scmi_device * sdev,u8 protocol_id)2336 scmi_devres_protocol_instance_get(struct scmi_device *sdev, u8 protocol_id)
2337 {
2338 struct scmi_protocol_instance *pi;
2339 struct scmi_protocol_devres *dres;
2340
2341 dres = devres_alloc(scmi_devm_release_protocol,
2342 sizeof(*dres), GFP_KERNEL);
2343 if (!dres)
2344 return ERR_PTR(-ENOMEM);
2345
2346 pi = scmi_get_protocol_instance(sdev->handle, protocol_id);
2347 if (IS_ERR(pi)) {
2348 devres_free(dres);
2349 return pi;
2350 }
2351
2352 dres->handle = sdev->handle;
2353 dres->protocol_id = protocol_id;
2354 devres_add(&sdev->dev, dres);
2355
2356 return pi;
2357 }
2358
2359 /**
2360 * scmi_devm_protocol_get - Devres managed get protocol operations and handle
2361 * @sdev: A reference to an scmi_device whose embedded struct device is to
2362 * be used for devres accounting.
2363 * @protocol_id: The protocol being requested.
2364 * @ph: A pointer reference used to pass back the associated protocol handle.
2365 *
2366 * Get hold of a protocol accounting for its usage, eventually triggering its
2367 * initialization, and returning the protocol specific operations and related
2368 * protocol handle which will be used as first argument in most of the
2369 * protocols operations methods.
2370 * Being a devres based managed method, protocol hold will be automatically
2371 * released, and possibly de-initialized on last user, once the SCMI driver
2372 * owning the scmi_device is unbound from it.
2373 *
2374 * Return: A reference to the requested protocol operations or error.
2375 * Must be checked for errors by caller.
2376 */
2377 static const void __must_check *
scmi_devm_protocol_get(struct scmi_device * sdev,u8 protocol_id,struct scmi_protocol_handle ** ph)2378 scmi_devm_protocol_get(struct scmi_device *sdev, u8 protocol_id,
2379 struct scmi_protocol_handle **ph)
2380 {
2381 struct scmi_protocol_instance *pi;
2382
2383 if (!ph)
2384 return ERR_PTR(-EINVAL);
2385
2386 pi = scmi_devres_protocol_instance_get(sdev, protocol_id);
2387 if (IS_ERR(pi))
2388 return pi;
2389
2390 *ph = &pi->ph;
2391
2392 return pi->proto->ops;
2393 }
2394
2395 /**
2396 * scmi_devm_protocol_acquire - Devres managed helper to get hold of a protocol
2397 * @sdev: A reference to an scmi_device whose embedded struct device is to
2398 * be used for devres accounting.
2399 * @protocol_id: The protocol being requested.
2400 *
2401 * Get hold of a protocol accounting for its usage, possibly triggering its
2402 * initialization but without getting access to its protocol specific operations
2403 * and handle.
2404 *
2405 * Being a devres based managed method, protocol hold will be automatically
2406 * released, and possibly de-initialized on last user, once the SCMI driver
2407 * owning the scmi_device is unbound from it.
2408 *
2409 * Return: 0 on SUCCESS
2410 */
scmi_devm_protocol_acquire(struct scmi_device * sdev,u8 protocol_id)2411 static int __must_check scmi_devm_protocol_acquire(struct scmi_device *sdev,
2412 u8 protocol_id)
2413 {
2414 struct scmi_protocol_instance *pi;
2415
2416 pi = scmi_devres_protocol_instance_get(sdev, protocol_id);
2417 if (IS_ERR(pi))
2418 return PTR_ERR(pi);
2419
2420 return 0;
2421 }
2422
scmi_devm_protocol_match(struct device * dev,void * res,void * data)2423 static int scmi_devm_protocol_match(struct device *dev, void *res, void *data)
2424 {
2425 struct scmi_protocol_devres *dres = res;
2426
2427 if (WARN_ON(!dres || !data))
2428 return 0;
2429
2430 return dres->protocol_id == *((u8 *)data);
2431 }
2432
2433 /**
2434 * scmi_devm_protocol_put - Devres managed put protocol operations and handle
2435 * @sdev: A reference to an scmi_device whose embedded struct device is to
2436 * be used for devres accounting.
2437 * @protocol_id: The protocol being requested.
2438 *
2439 * Explicitly release a protocol hold previously obtained calling the above
2440 * @scmi_devm_protocol_get.
2441 */
scmi_devm_protocol_put(struct scmi_device * sdev,u8 protocol_id)2442 static void scmi_devm_protocol_put(struct scmi_device *sdev, u8 protocol_id)
2443 {
2444 int ret;
2445
2446 ret = devres_release(&sdev->dev, scmi_devm_release_protocol,
2447 scmi_devm_protocol_match, &protocol_id);
2448 WARN_ON(ret);
2449 }
2450
2451 /**
2452 * scmi_is_transport_atomic - Method to check if underlying transport for an
2453 * SCMI instance is configured as atomic.
2454 *
2455 * @handle: A reference to the SCMI platform instance.
2456 * @atomic_threshold: An optional return value for the system wide currently
2457 * configured threshold for atomic operations.
2458 *
2459 * Return: True if transport is configured as atomic
2460 */
scmi_is_transport_atomic(const struct scmi_handle * handle,unsigned int * atomic_threshold)2461 static bool scmi_is_transport_atomic(const struct scmi_handle *handle,
2462 unsigned int *atomic_threshold)
2463 {
2464 bool ret;
2465 struct scmi_info *info = handle_to_scmi_info(handle);
2466
2467 ret = info->desc->atomic_enabled &&
2468 is_transport_polling_capable(info->desc);
2469 if (ret && atomic_threshold)
2470 *atomic_threshold = info->desc->atomic_threshold;
2471
2472 return ret;
2473 }
2474
2475 /**
2476 * scmi_handle_get() - Get the SCMI handle for a device
2477 *
2478 * @dev: pointer to device for which we want SCMI handle
2479 *
2480 * NOTE: The function does not track individual clients of the framework
2481 * and is expected to be maintained by caller of SCMI protocol library.
2482 * scmi_handle_put must be balanced with successful scmi_handle_get
2483 *
2484 * Return: pointer to handle if successful, NULL on error
2485 */
scmi_handle_get(struct device * dev)2486 static struct scmi_handle *scmi_handle_get(struct device *dev)
2487 {
2488 struct list_head *p;
2489 struct scmi_info *info;
2490 struct scmi_handle *handle = NULL;
2491
2492 mutex_lock(&scmi_list_mutex);
2493 list_for_each(p, &scmi_list) {
2494 info = list_entry(p, struct scmi_info, node);
2495 if (dev->parent == info->dev) {
2496 info->users++;
2497 handle = &info->handle;
2498 break;
2499 }
2500 }
2501 mutex_unlock(&scmi_list_mutex);
2502
2503 return handle;
2504 }
2505
2506 /**
2507 * scmi_handle_put() - Release the handle acquired by scmi_handle_get
2508 *
2509 * @handle: handle acquired by scmi_handle_get
2510 *
2511 * NOTE: The function does not track individual clients of the framework
2512 * and is expected to be maintained by caller of SCMI protocol library.
2513 * scmi_handle_put must be balanced with successful scmi_handle_get
2514 *
2515 * Return: 0 is successfully released
2516 * if null was passed, it returns -EINVAL;
2517 */
scmi_handle_put(const struct scmi_handle * handle)2518 static int scmi_handle_put(const struct scmi_handle *handle)
2519 {
2520 struct scmi_info *info;
2521
2522 if (!handle)
2523 return -EINVAL;
2524
2525 info = handle_to_scmi_info(handle);
2526 mutex_lock(&scmi_list_mutex);
2527 if (!WARN_ON(!info->users))
2528 info->users--;
2529 mutex_unlock(&scmi_list_mutex);
2530
2531 return 0;
2532 }
2533
scmi_device_link_add(struct device * consumer,struct device * supplier)2534 static void scmi_device_link_add(struct device *consumer,
2535 struct device *supplier)
2536 {
2537 struct device_link *link;
2538
2539 link = device_link_add(consumer, supplier, DL_FLAG_AUTOREMOVE_CONSUMER);
2540
2541 WARN_ON(!link);
2542 }
2543
scmi_set_handle(struct scmi_device * scmi_dev)2544 static void scmi_set_handle(struct scmi_device *scmi_dev)
2545 {
2546 scmi_dev->handle = scmi_handle_get(&scmi_dev->dev);
2547 if (scmi_dev->handle)
2548 scmi_device_link_add(&scmi_dev->dev, scmi_dev->handle->dev);
2549 }
2550
__scmi_xfer_info_init(struct scmi_info * sinfo,struct scmi_xfers_info * info)2551 static int __scmi_xfer_info_init(struct scmi_info *sinfo,
2552 struct scmi_xfers_info *info)
2553 {
2554 int i;
2555 struct scmi_xfer *xfer;
2556 struct device *dev = sinfo->dev;
2557 const struct scmi_desc *desc = sinfo->desc;
2558
2559 /* Pre-allocated messages, no more than what hdr.seq can support */
2560 if (WARN_ON(!info->max_msg || info->max_msg > MSG_TOKEN_MAX)) {
2561 dev_err(dev,
2562 "Invalid maximum messages %d, not in range [1 - %lu]\n",
2563 info->max_msg, MSG_TOKEN_MAX);
2564 return -EINVAL;
2565 }
2566
2567 hash_init(info->pending_xfers);
2568
2569 /* Allocate a bitmask sized to hold MSG_TOKEN_MAX tokens */
2570 info->xfer_alloc_table = devm_bitmap_zalloc(dev, MSG_TOKEN_MAX,
2571 GFP_KERNEL);
2572 if (!info->xfer_alloc_table)
2573 return -ENOMEM;
2574
2575 /*
2576 * Preallocate a number of xfers equal to max inflight messages,
2577 * pre-initialize the buffer pointer to pre-allocated buffers and
2578 * attach all of them to the free list
2579 */
2580 INIT_HLIST_HEAD(&info->free_xfers);
2581 for (i = 0; i < info->max_msg; i++) {
2582 xfer = devm_kzalloc(dev, sizeof(*xfer), GFP_KERNEL);
2583 if (!xfer)
2584 return -ENOMEM;
2585
2586 xfer->rx.buf = devm_kcalloc(dev, sizeof(u8), desc->max_msg_size,
2587 GFP_KERNEL);
2588 if (!xfer->rx.buf)
2589 return -ENOMEM;
2590
2591 xfer->tx.buf = xfer->rx.buf;
2592 init_completion(&xfer->done);
2593 spin_lock_init(&xfer->lock);
2594
2595 /* Add initialized xfer to the free list */
2596 hlist_add_head(&xfer->node, &info->free_xfers);
2597 }
2598
2599 spin_lock_init(&info->xfer_lock);
2600
2601 return 0;
2602 }
2603
scmi_channels_max_msg_configure(struct scmi_info * sinfo)2604 static int scmi_channels_max_msg_configure(struct scmi_info *sinfo)
2605 {
2606 const struct scmi_desc *desc = sinfo->desc;
2607
2608 if (!desc->ops->get_max_msg) {
2609 sinfo->tx_minfo.max_msg = desc->max_msg;
2610 sinfo->rx_minfo.max_msg = desc->max_msg;
2611 } else {
2612 struct scmi_chan_info *base_cinfo;
2613
2614 base_cinfo = idr_find(&sinfo->tx_idr, SCMI_PROTOCOL_BASE);
2615 if (!base_cinfo)
2616 return -EINVAL;
2617 sinfo->tx_minfo.max_msg = desc->ops->get_max_msg(base_cinfo);
2618
2619 /* RX channel is optional so can be skipped */
2620 base_cinfo = idr_find(&sinfo->rx_idr, SCMI_PROTOCOL_BASE);
2621 if (base_cinfo)
2622 sinfo->rx_minfo.max_msg =
2623 desc->ops->get_max_msg(base_cinfo);
2624 }
2625
2626 return 0;
2627 }
2628
scmi_xfer_info_init(struct scmi_info * sinfo)2629 static int scmi_xfer_info_init(struct scmi_info *sinfo)
2630 {
2631 int ret;
2632
2633 ret = scmi_channels_max_msg_configure(sinfo);
2634 if (ret)
2635 return ret;
2636
2637 ret = __scmi_xfer_info_init(sinfo, &sinfo->tx_minfo);
2638 if (!ret && !idr_is_empty(&sinfo->rx_idr))
2639 ret = __scmi_xfer_info_init(sinfo, &sinfo->rx_minfo);
2640
2641 return ret;
2642 }
2643
scmi_chan_setup(struct scmi_info * info,struct device_node * of_node,int prot_id,bool tx)2644 static int scmi_chan_setup(struct scmi_info *info, struct device_node *of_node,
2645 int prot_id, bool tx)
2646 {
2647 int ret, idx;
2648 char name[32];
2649 struct scmi_chan_info *cinfo;
2650 struct idr *idr;
2651 struct scmi_device *tdev = NULL;
2652
2653 /* Transmit channel is first entry i.e. index 0 */
2654 idx = tx ? 0 : 1;
2655 idr = tx ? &info->tx_idr : &info->rx_idr;
2656
2657 if (!info->desc->ops->chan_available(of_node, idx)) {
2658 cinfo = idr_find(idr, SCMI_PROTOCOL_BASE);
2659 if (unlikely(!cinfo)) /* Possible only if platform has no Rx */
2660 return -EINVAL;
2661 goto idr_alloc;
2662 }
2663
2664 cinfo = devm_kzalloc(info->dev, sizeof(*cinfo), GFP_KERNEL);
2665 if (!cinfo)
2666 return -ENOMEM;
2667
2668 cinfo->is_p2a = !tx;
2669 cinfo->rx_timeout_ms = info->desc->max_rx_timeout_ms;
2670 cinfo->max_msg_size = info->desc->max_msg_size;
2671
2672 /* Create a unique name for this transport device */
2673 snprintf(name, 32, "__scmi_transport_device_%s_%02X",
2674 idx ? "rx" : "tx", prot_id);
2675 /* Create a uniquely named, dedicated transport device for this chan */
2676 tdev = scmi_device_create(of_node, info->dev, prot_id, name);
2677 if (!tdev) {
2678 dev_err(info->dev,
2679 "failed to create transport device (%s)\n", name);
2680 devm_kfree(info->dev, cinfo);
2681 return -EINVAL;
2682 }
2683 of_node_get(of_node);
2684
2685 cinfo->id = prot_id;
2686 cinfo->dev = &tdev->dev;
2687 ret = info->desc->ops->chan_setup(cinfo, info->dev, tx);
2688 if (ret) {
2689 of_node_put(of_node);
2690 scmi_device_destroy(info->dev, prot_id, name);
2691 devm_kfree(info->dev, cinfo);
2692 return ret;
2693 }
2694
2695 if (tx && is_polling_required(cinfo, info->desc)) {
2696 if (is_transport_polling_capable(info->desc))
2697 dev_info(&tdev->dev,
2698 "Enabled polling mode TX channel - prot_id:%d\n",
2699 prot_id);
2700 else
2701 dev_warn(&tdev->dev,
2702 "Polling mode NOT supported by transport.\n");
2703 }
2704
2705 idr_alloc:
2706 ret = idr_alloc(idr, cinfo, prot_id, prot_id + 1, GFP_KERNEL);
2707 if (ret != prot_id) {
2708 dev_err(info->dev,
2709 "unable to allocate SCMI idr slot err %d\n", ret);
2710 /* Destroy channel and device only if created by this call. */
2711 if (tdev) {
2712 of_node_put(of_node);
2713 scmi_device_destroy(info->dev, prot_id, name);
2714 devm_kfree(info->dev, cinfo);
2715 }
2716 return ret;
2717 }
2718
2719 cinfo->handle = &info->handle;
2720 return 0;
2721 }
2722
2723 static inline int
scmi_txrx_setup(struct scmi_info * info,struct device_node * of_node,int prot_id)2724 scmi_txrx_setup(struct scmi_info *info, struct device_node *of_node,
2725 int prot_id)
2726 {
2727 int ret = scmi_chan_setup(info, of_node, prot_id, true);
2728
2729 if (!ret) {
2730 /* Rx is optional, report only memory errors */
2731 ret = scmi_chan_setup(info, of_node, prot_id, false);
2732 if (ret && ret != -ENOMEM)
2733 ret = 0;
2734 }
2735
2736 if (ret)
2737 dev_err(info->dev,
2738 "failed to setup channel for protocol:0x%X\n", prot_id);
2739
2740 return ret;
2741 }
2742
2743 /**
2744 * scmi_channels_setup - Helper to initialize all required channels
2745 *
2746 * @info: The SCMI instance descriptor.
2747 *
2748 * Initialize all the channels found described in the DT against the underlying
2749 * configured transport using custom defined dedicated devices instead of
2750 * borrowing devices from the SCMI drivers; this way channels are initialized
2751 * upfront during core SCMI stack probing and are no more coupled with SCMI
2752 * devices used by SCMI drivers.
2753 *
2754 * Note that, even though a pair of TX/RX channels is associated to each
2755 * protocol defined in the DT, a distinct freshly initialized channel is
2756 * created only if the DT node for the protocol at hand describes a dedicated
2757 * channel: in all the other cases the common BASE protocol channel is reused.
2758 *
2759 * Return: 0 on Success
2760 */
scmi_channels_setup(struct scmi_info * info)2761 static int scmi_channels_setup(struct scmi_info *info)
2762 {
2763 int ret;
2764 struct device_node *top_np = info->dev->of_node;
2765
2766 /* Initialize a common generic channel at first */
2767 ret = scmi_txrx_setup(info, top_np, SCMI_PROTOCOL_BASE);
2768 if (ret)
2769 return ret;
2770
2771 for_each_available_child_of_node_scoped(top_np, child) {
2772 u32 prot_id;
2773
2774 if (of_property_read_u32(child, "reg", &prot_id))
2775 continue;
2776
2777 if (!FIELD_FIT(MSG_PROTOCOL_ID_MASK, prot_id))
2778 dev_err(info->dev,
2779 "Out of range protocol %d\n", prot_id);
2780
2781 ret = scmi_txrx_setup(info, child, prot_id);
2782 if (ret)
2783 return ret;
2784 }
2785
2786 return 0;
2787 }
2788
scmi_chan_destroy(int id,void * p,void * idr)2789 static int scmi_chan_destroy(int id, void *p, void *idr)
2790 {
2791 struct scmi_chan_info *cinfo = p;
2792
2793 if (cinfo->dev) {
2794 struct scmi_info *info = handle_to_scmi_info(cinfo->handle);
2795 struct scmi_device *sdev = to_scmi_dev(cinfo->dev);
2796
2797 of_node_put(cinfo->dev->of_node);
2798 scmi_device_destroy(info->dev, id, sdev->name);
2799 cinfo->dev = NULL;
2800 }
2801
2802 idr_remove(idr, id);
2803
2804 return 0;
2805 }
2806
scmi_cleanup_channels(struct scmi_info * info,struct idr * idr)2807 static void scmi_cleanup_channels(struct scmi_info *info, struct idr *idr)
2808 {
2809 /* At first free all channels at the transport layer ... */
2810 idr_for_each(idr, info->desc->ops->chan_free, idr);
2811
2812 /* ...then destroy all underlying devices */
2813 idr_for_each(idr, scmi_chan_destroy, idr);
2814
2815 idr_destroy(idr);
2816 }
2817
scmi_cleanup_txrx_channels(struct scmi_info * info)2818 static void scmi_cleanup_txrx_channels(struct scmi_info *info)
2819 {
2820 scmi_cleanup_channels(info, &info->tx_idr);
2821
2822 scmi_cleanup_channels(info, &info->rx_idr);
2823 }
2824
scmi_bus_notifier(struct notifier_block * nb,unsigned long action,void * data)2825 static int scmi_bus_notifier(struct notifier_block *nb,
2826 unsigned long action, void *data)
2827 {
2828 struct scmi_info *info = bus_nb_to_scmi_info(nb);
2829 struct scmi_device *sdev = to_scmi_dev(data);
2830
2831 /* Skip transport devices and devices of different SCMI instances */
2832 if (!strncmp(sdev->name, "__scmi_transport_device", 23) ||
2833 sdev->dev.parent != info->dev)
2834 return NOTIFY_DONE;
2835
2836 switch (action) {
2837 case BUS_NOTIFY_BIND_DRIVER:
2838 /* setup handle now as the transport is ready */
2839 scmi_set_handle(sdev);
2840 break;
2841 case BUS_NOTIFY_UNBOUND_DRIVER:
2842 scmi_handle_put(sdev->handle);
2843 sdev->handle = NULL;
2844 break;
2845 default:
2846 return NOTIFY_DONE;
2847 }
2848
2849 dev_dbg(info->dev, "Device %s (%s) is now %s\n", dev_name(&sdev->dev),
2850 sdev->name, action == BUS_NOTIFY_BIND_DRIVER ?
2851 "about to be BOUND." : "UNBOUND.");
2852
2853 return NOTIFY_OK;
2854 }
2855
scmi_device_request_notifier(struct notifier_block * nb,unsigned long action,void * data)2856 static int scmi_device_request_notifier(struct notifier_block *nb,
2857 unsigned long action, void *data)
2858 {
2859 struct device_node *np;
2860 struct scmi_device_id *id_table = data;
2861 struct scmi_info *info = req_nb_to_scmi_info(nb);
2862
2863 np = idr_find(&info->active_protocols, id_table->protocol_id);
2864 if (!np)
2865 return NOTIFY_DONE;
2866
2867 dev_dbg(info->dev, "%sRequested device (%s) for protocol 0x%x\n",
2868 action == SCMI_BUS_NOTIFY_DEVICE_REQUEST ? "" : "UN-",
2869 id_table->name, id_table->protocol_id);
2870
2871 switch (action) {
2872 case SCMI_BUS_NOTIFY_DEVICE_REQUEST:
2873 scmi_create_protocol_devices(np, info, id_table->protocol_id,
2874 id_table->name);
2875 break;
2876 case SCMI_BUS_NOTIFY_DEVICE_UNREQUEST:
2877 scmi_destroy_protocol_devices(info, id_table->protocol_id,
2878 id_table->name);
2879 break;
2880 default:
2881 return NOTIFY_DONE;
2882 }
2883
2884 return NOTIFY_OK;
2885 }
2886
2887 static const char * const dbg_counter_strs[] = {
2888 "sent_ok",
2889 "sent_fail",
2890 "sent_fail_polling_unsupported",
2891 "sent_fail_channel_not_found",
2892 "response_ok",
2893 "notification_ok",
2894 "delayed_response_ok",
2895 "xfers_response_timeout",
2896 "xfers_response_polled_timeout",
2897 "response_polled_ok",
2898 "err_msg_unexpected",
2899 "err_msg_invalid",
2900 "err_msg_nomem",
2901 "err_protocol",
2902 };
2903
reset_all_on_write(struct file * filp,const char __user * buf,size_t count,loff_t * ppos)2904 static ssize_t reset_all_on_write(struct file *filp, const char __user *buf,
2905 size_t count, loff_t *ppos)
2906 {
2907 struct scmi_debug_info *dbg = filp->private_data;
2908
2909 for (int i = 0; i < SCMI_DEBUG_COUNTERS_LAST; i++)
2910 atomic_set(&dbg->counters[i], 0);
2911
2912 return count;
2913 }
2914
2915 static const struct file_operations fops_reset_counts = {
2916 .owner = THIS_MODULE,
2917 .open = simple_open,
2918 .write = reset_all_on_write,
2919 };
2920
scmi_debugfs_counters_setup(struct scmi_debug_info * dbg,struct dentry * trans)2921 static void scmi_debugfs_counters_setup(struct scmi_debug_info *dbg,
2922 struct dentry *trans)
2923 {
2924 struct dentry *counters;
2925 int idx;
2926
2927 counters = debugfs_create_dir("counters", trans);
2928
2929 for (idx = 0; idx < SCMI_DEBUG_COUNTERS_LAST; idx++)
2930 debugfs_create_atomic_t(dbg_counter_strs[idx], 0600, counters,
2931 &dbg->counters[idx]);
2932
2933 debugfs_create_file("reset", 0200, counters, dbg, &fops_reset_counts);
2934 }
2935
scmi_debugfs_common_cleanup(void * d)2936 static void scmi_debugfs_common_cleanup(void *d)
2937 {
2938 struct scmi_debug_info *dbg = d;
2939
2940 if (!dbg)
2941 return;
2942
2943 debugfs_remove_recursive(dbg->top_dentry);
2944 kfree(dbg->name);
2945 kfree(dbg->type);
2946 }
2947
scmi_debugfs_common_setup(struct scmi_info * info)2948 static struct scmi_debug_info *scmi_debugfs_common_setup(struct scmi_info *info)
2949 {
2950 char top_dir[16];
2951 struct dentry *trans, *top_dentry;
2952 struct scmi_debug_info *dbg;
2953 const char *c_ptr = NULL;
2954
2955 dbg = devm_kzalloc(info->dev, sizeof(*dbg), GFP_KERNEL);
2956 if (!dbg)
2957 return NULL;
2958
2959 dbg->name = kstrdup(of_node_full_name(info->dev->of_node), GFP_KERNEL);
2960 if (!dbg->name) {
2961 devm_kfree(info->dev, dbg);
2962 return NULL;
2963 }
2964
2965 of_property_read_string(info->dev->of_node, "compatible", &c_ptr);
2966 dbg->type = kstrdup(c_ptr, GFP_KERNEL);
2967 if (!dbg->type) {
2968 kfree(dbg->name);
2969 devm_kfree(info->dev, dbg);
2970 return NULL;
2971 }
2972
2973 snprintf(top_dir, 16, "%d", info->id);
2974 top_dentry = debugfs_create_dir(top_dir, scmi_top_dentry);
2975 trans = debugfs_create_dir("transport", top_dentry);
2976
2977 dbg->is_atomic = info->desc->atomic_enabled &&
2978 is_transport_polling_capable(info->desc);
2979
2980 debugfs_create_str("instance_name", 0400, top_dentry,
2981 (char **)&dbg->name);
2982
2983 debugfs_create_u32("atomic_threshold_us", 0400, top_dentry,
2984 (u32 *)&info->desc->atomic_threshold);
2985
2986 debugfs_create_str("type", 0400, trans, (char **)&dbg->type);
2987
2988 debugfs_create_bool("is_atomic", 0400, trans, &dbg->is_atomic);
2989
2990 debugfs_create_u32("max_rx_timeout_ms", 0400, trans,
2991 (u32 *)&info->desc->max_rx_timeout_ms);
2992
2993 debugfs_create_u32("max_msg_size", 0400, trans,
2994 (u32 *)&info->desc->max_msg_size);
2995
2996 debugfs_create_u32("tx_max_msg", 0400, trans,
2997 (u32 *)&info->tx_minfo.max_msg);
2998
2999 debugfs_create_u32("rx_max_msg", 0400, trans,
3000 (u32 *)&info->rx_minfo.max_msg);
3001
3002 if (IS_ENABLED(CONFIG_ARM_SCMI_DEBUG_COUNTERS))
3003 scmi_debugfs_counters_setup(dbg, trans);
3004
3005 dbg->top_dentry = top_dentry;
3006
3007 if (devm_add_action_or_reset(info->dev,
3008 scmi_debugfs_common_cleanup, dbg))
3009 return NULL;
3010
3011 return dbg;
3012 }
3013
scmi_debugfs_raw_mode_setup(struct scmi_info * info)3014 static int scmi_debugfs_raw_mode_setup(struct scmi_info *info)
3015 {
3016 int id, num_chans = 0, ret = 0;
3017 struct scmi_chan_info *cinfo;
3018 u8 channels[SCMI_MAX_CHANNELS] = {};
3019 DECLARE_BITMAP(protos, SCMI_MAX_CHANNELS) = {};
3020
3021 if (!info->dbg)
3022 return -EINVAL;
3023
3024 /* Enumerate all channels to collect their ids */
3025 idr_for_each_entry(&info->tx_idr, cinfo, id) {
3026 /*
3027 * Cannot happen, but be defensive.
3028 * Zero as num_chans is ok, warn and carry on.
3029 */
3030 if (num_chans >= SCMI_MAX_CHANNELS || !cinfo) {
3031 dev_warn(info->dev,
3032 "SCMI RAW - Error enumerating channels\n");
3033 break;
3034 }
3035
3036 if (!test_bit(cinfo->id, protos)) {
3037 channels[num_chans++] = cinfo->id;
3038 set_bit(cinfo->id, protos);
3039 }
3040 }
3041
3042 info->raw = scmi_raw_mode_init(&info->handle, info->dbg->top_dentry,
3043 info->id, channels, num_chans,
3044 info->desc, info->tx_minfo.max_msg);
3045 if (IS_ERR(info->raw)) {
3046 dev_err(info->dev, "Failed to initialize SCMI RAW Mode !\n");
3047 ret = PTR_ERR(info->raw);
3048 info->raw = NULL;
3049 }
3050
3051 return ret;
3052 }
3053
scmi_transport_setup(struct device * dev)3054 static const struct scmi_desc *scmi_transport_setup(struct device *dev)
3055 {
3056 struct scmi_transport *trans;
3057 int ret;
3058
3059 trans = dev_get_platdata(dev);
3060 if (!trans || !trans->supplier || !trans->core_ops)
3061 return NULL;
3062
3063 if (!device_link_add(dev, trans->supplier, DL_FLAG_AUTOREMOVE_CONSUMER)) {
3064 dev_err(dev,
3065 "Adding link to supplier transport device failed\n");
3066 return NULL;
3067 }
3068
3069 /* Provide core transport ops */
3070 *trans->core_ops = &scmi_trans_core_ops;
3071
3072 dev_info(dev, "Using %s\n", dev_driver_string(trans->supplier));
3073
3074 ret = of_property_read_u32(dev->of_node, "arm,max-rx-timeout-ms",
3075 &trans->desc.max_rx_timeout_ms);
3076 if (ret && ret != -EINVAL)
3077 dev_err(dev, "Malformed arm,max-rx-timeout-ms DT property.\n");
3078
3079 ret = of_property_read_u32(dev->of_node, "arm,max-msg-size",
3080 &trans->desc.max_msg_size);
3081 if (ret && ret != -EINVAL)
3082 dev_err(dev, "Malformed arm,max-msg-size DT property.\n");
3083
3084 ret = of_property_read_u32(dev->of_node, "arm,max-msg",
3085 &trans->desc.max_msg);
3086 if (ret && ret != -EINVAL)
3087 dev_err(dev, "Malformed arm,max-msg DT property.\n");
3088
3089 dev_info(dev,
3090 "SCMI max-rx-timeout: %dms / max-msg-size: %dbytes / max-msg: %d\n",
3091 trans->desc.max_rx_timeout_ms, trans->desc.max_msg_size,
3092 trans->desc.max_msg);
3093
3094 /* System wide atomic threshold for atomic ops .. if any */
3095 if (!of_property_read_u32(dev->of_node, "atomic-threshold-us",
3096 &trans->desc.atomic_threshold))
3097 dev_info(dev,
3098 "SCMI System wide atomic threshold set to %u us\n",
3099 trans->desc.atomic_threshold);
3100
3101 return &trans->desc;
3102 }
3103
scmi_probe(struct platform_device * pdev)3104 static int scmi_probe(struct platform_device *pdev)
3105 {
3106 int ret;
3107 char *err_str = "probe failure\n";
3108 struct scmi_handle *handle;
3109 const struct scmi_desc *desc;
3110 struct scmi_info *info;
3111 bool coex = IS_ENABLED(CONFIG_ARM_SCMI_RAW_MODE_SUPPORT_COEX);
3112 struct device *dev = &pdev->dev;
3113 struct device_node *child, *np = dev->of_node;
3114
3115 desc = scmi_transport_setup(dev);
3116 if (!desc) {
3117 err_str = "transport invalid\n";
3118 ret = -EINVAL;
3119 goto out_err;
3120 }
3121
3122 info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL);
3123 if (!info)
3124 return -ENOMEM;
3125
3126 info->id = ida_alloc_min(&scmi_id, 0, GFP_KERNEL);
3127 if (info->id < 0)
3128 return info->id;
3129
3130 info->dev = dev;
3131 info->desc = desc;
3132 info->bus_nb.notifier_call = scmi_bus_notifier;
3133 info->dev_req_nb.notifier_call = scmi_device_request_notifier;
3134 INIT_LIST_HEAD(&info->node);
3135 idr_init(&info->protocols);
3136 mutex_init(&info->protocols_mtx);
3137 idr_init(&info->active_protocols);
3138 mutex_init(&info->devreq_mtx);
3139
3140 platform_set_drvdata(pdev, info);
3141 idr_init(&info->tx_idr);
3142 idr_init(&info->rx_idr);
3143
3144 handle = &info->handle;
3145 handle->dev = info->dev;
3146 handle->version = &info->version;
3147 handle->devm_protocol_acquire = scmi_devm_protocol_acquire;
3148 handle->devm_protocol_get = scmi_devm_protocol_get;
3149 handle->devm_protocol_put = scmi_devm_protocol_put;
3150 handle->is_transport_atomic = scmi_is_transport_atomic;
3151
3152 /* Setup all channels described in the DT at first */
3153 ret = scmi_channels_setup(info);
3154 if (ret) {
3155 err_str = "failed to setup channels\n";
3156 goto clear_ida;
3157 }
3158
3159 ret = bus_register_notifier(&scmi_bus_type, &info->bus_nb);
3160 if (ret) {
3161 err_str = "failed to register bus notifier\n";
3162 goto clear_txrx_setup;
3163 }
3164
3165 ret = blocking_notifier_chain_register(&scmi_requested_devices_nh,
3166 &info->dev_req_nb);
3167 if (ret) {
3168 err_str = "failed to register device notifier\n";
3169 goto clear_bus_notifier;
3170 }
3171
3172 ret = scmi_xfer_info_init(info);
3173 if (ret) {
3174 err_str = "failed to init xfers pool\n";
3175 goto clear_dev_req_notifier;
3176 }
3177
3178 if (scmi_top_dentry) {
3179 info->dbg = scmi_debugfs_common_setup(info);
3180 if (!info->dbg)
3181 dev_warn(dev, "Failed to setup SCMI debugfs.\n");
3182
3183 if (IS_ENABLED(CONFIG_ARM_SCMI_RAW_MODE_SUPPORT)) {
3184 ret = scmi_debugfs_raw_mode_setup(info);
3185 if (!coex) {
3186 if (ret)
3187 goto clear_dev_req_notifier;
3188
3189 /* Bail out anyway when coex disabled. */
3190 return 0;
3191 }
3192
3193 /* Coex enabled, carry on in any case. */
3194 dev_info(dev, "SCMI RAW Mode COEX enabled !\n");
3195 }
3196 }
3197
3198 if (scmi_notification_init(handle))
3199 dev_err(dev, "SCMI Notifications NOT available.\n");
3200
3201 if (info->desc->atomic_enabled &&
3202 !is_transport_polling_capable(info->desc))
3203 dev_err(dev,
3204 "Transport is not polling capable. Atomic mode not supported.\n");
3205
3206 /*
3207 * Trigger SCMI Base protocol initialization.
3208 * It's mandatory and won't be ever released/deinit until the
3209 * SCMI stack is shutdown/unloaded as a whole.
3210 */
3211 ret = scmi_protocol_acquire(handle, SCMI_PROTOCOL_BASE);
3212 if (ret) {
3213 err_str = "unable to communicate with SCMI\n";
3214 if (coex) {
3215 dev_err(dev, "%s", err_str);
3216 return 0;
3217 }
3218 goto notification_exit;
3219 }
3220
3221 mutex_lock(&scmi_list_mutex);
3222 list_add_tail(&info->node, &scmi_list);
3223 mutex_unlock(&scmi_list_mutex);
3224
3225 for_each_available_child_of_node(np, child) {
3226 u32 prot_id;
3227
3228 if (of_property_read_u32(child, "reg", &prot_id))
3229 continue;
3230
3231 if (!FIELD_FIT(MSG_PROTOCOL_ID_MASK, prot_id))
3232 dev_err(dev, "Out of range protocol %d\n", prot_id);
3233
3234 if (!scmi_is_protocol_implemented(handle, prot_id)) {
3235 dev_err(dev, "SCMI protocol %d not implemented\n",
3236 prot_id);
3237 continue;
3238 }
3239
3240 /*
3241 * Save this valid DT protocol descriptor amongst
3242 * @active_protocols for this SCMI instance/
3243 */
3244 ret = idr_alloc(&info->active_protocols, child,
3245 prot_id, prot_id + 1, GFP_KERNEL);
3246 if (ret != prot_id) {
3247 dev_err(dev, "SCMI protocol %d already activated. Skip\n",
3248 prot_id);
3249 continue;
3250 }
3251
3252 of_node_get(child);
3253 scmi_create_protocol_devices(child, info, prot_id, NULL);
3254 }
3255
3256 return 0;
3257
3258 notification_exit:
3259 if (IS_ENABLED(CONFIG_ARM_SCMI_RAW_MODE_SUPPORT))
3260 scmi_raw_mode_cleanup(info->raw);
3261 scmi_notification_exit(&info->handle);
3262 clear_dev_req_notifier:
3263 blocking_notifier_chain_unregister(&scmi_requested_devices_nh,
3264 &info->dev_req_nb);
3265 clear_bus_notifier:
3266 bus_unregister_notifier(&scmi_bus_type, &info->bus_nb);
3267 clear_txrx_setup:
3268 scmi_cleanup_txrx_channels(info);
3269 clear_ida:
3270 ida_free(&scmi_id, info->id);
3271
3272 out_err:
3273 return dev_err_probe(dev, ret, "%s", err_str);
3274 }
3275
scmi_remove(struct platform_device * pdev)3276 static void scmi_remove(struct platform_device *pdev)
3277 {
3278 int id;
3279 struct scmi_info *info = platform_get_drvdata(pdev);
3280 struct device_node *child;
3281
3282 if (IS_ENABLED(CONFIG_ARM_SCMI_RAW_MODE_SUPPORT))
3283 scmi_raw_mode_cleanup(info->raw);
3284
3285 mutex_lock(&scmi_list_mutex);
3286 if (info->users)
3287 dev_warn(&pdev->dev,
3288 "Still active SCMI users will be forcibly unbound.\n");
3289 list_del(&info->node);
3290 mutex_unlock(&scmi_list_mutex);
3291
3292 scmi_notification_exit(&info->handle);
3293
3294 mutex_lock(&info->protocols_mtx);
3295 idr_destroy(&info->protocols);
3296 mutex_unlock(&info->protocols_mtx);
3297
3298 idr_for_each_entry(&info->active_protocols, child, id)
3299 of_node_put(child);
3300 idr_destroy(&info->active_protocols);
3301
3302 blocking_notifier_chain_unregister(&scmi_requested_devices_nh,
3303 &info->dev_req_nb);
3304 bus_unregister_notifier(&scmi_bus_type, &info->bus_nb);
3305
3306 /* Safe to free channels since no more users */
3307 scmi_cleanup_txrx_channels(info);
3308
3309 ida_free(&scmi_id, info->id);
3310 }
3311
protocol_version_show(struct device * dev,struct device_attribute * attr,char * buf)3312 static ssize_t protocol_version_show(struct device *dev,
3313 struct device_attribute *attr, char *buf)
3314 {
3315 struct scmi_info *info = dev_get_drvdata(dev);
3316
3317 return sprintf(buf, "%u.%u\n", info->version.major_ver,
3318 info->version.minor_ver);
3319 }
3320 static DEVICE_ATTR_RO(protocol_version);
3321
firmware_version_show(struct device * dev,struct device_attribute * attr,char * buf)3322 static ssize_t firmware_version_show(struct device *dev,
3323 struct device_attribute *attr, char *buf)
3324 {
3325 struct scmi_info *info = dev_get_drvdata(dev);
3326
3327 return sprintf(buf, "0x%x\n", info->version.impl_ver);
3328 }
3329 static DEVICE_ATTR_RO(firmware_version);
3330
vendor_id_show(struct device * dev,struct device_attribute * attr,char * buf)3331 static ssize_t vendor_id_show(struct device *dev,
3332 struct device_attribute *attr, char *buf)
3333 {
3334 struct scmi_info *info = dev_get_drvdata(dev);
3335
3336 return sprintf(buf, "%s\n", info->version.vendor_id);
3337 }
3338 static DEVICE_ATTR_RO(vendor_id);
3339
sub_vendor_id_show(struct device * dev,struct device_attribute * attr,char * buf)3340 static ssize_t sub_vendor_id_show(struct device *dev,
3341 struct device_attribute *attr, char *buf)
3342 {
3343 struct scmi_info *info = dev_get_drvdata(dev);
3344
3345 return sprintf(buf, "%s\n", info->version.sub_vendor_id);
3346 }
3347 static DEVICE_ATTR_RO(sub_vendor_id);
3348
3349 static struct attribute *versions_attrs[] = {
3350 &dev_attr_firmware_version.attr,
3351 &dev_attr_protocol_version.attr,
3352 &dev_attr_vendor_id.attr,
3353 &dev_attr_sub_vendor_id.attr,
3354 NULL,
3355 };
3356 ATTRIBUTE_GROUPS(versions);
3357
3358 static struct platform_driver scmi_driver = {
3359 .driver = {
3360 .name = "arm-scmi",
3361 .suppress_bind_attrs = true,
3362 .dev_groups = versions_groups,
3363 },
3364 .probe = scmi_probe,
3365 .remove = scmi_remove,
3366 };
3367
scmi_debugfs_init(void)3368 static struct dentry *scmi_debugfs_init(void)
3369 {
3370 struct dentry *d;
3371
3372 d = debugfs_create_dir("scmi", NULL);
3373 if (IS_ERR(d)) {
3374 pr_err("Could NOT create SCMI top dentry.\n");
3375 return NULL;
3376 }
3377
3378 return d;
3379 }
3380
scmi_driver_init(void)3381 static int __init scmi_driver_init(void)
3382 {
3383 /* Bail out if no SCMI transport was configured */
3384 if (WARN_ON(!IS_ENABLED(CONFIG_ARM_SCMI_HAVE_TRANSPORT)))
3385 return -EINVAL;
3386
3387 if (IS_ENABLED(CONFIG_ARM_SCMI_HAVE_SHMEM))
3388 scmi_trans_core_ops.shmem = scmi_shared_mem_operations_get();
3389
3390 if (IS_ENABLED(CONFIG_ARM_SCMI_HAVE_MSG))
3391 scmi_trans_core_ops.msg = scmi_message_operations_get();
3392
3393 if (IS_ENABLED(CONFIG_ARM_SCMI_NEED_DEBUGFS))
3394 scmi_top_dentry = scmi_debugfs_init();
3395
3396 scmi_base_register();
3397
3398 scmi_clock_register();
3399 scmi_perf_register();
3400 scmi_power_register();
3401 scmi_reset_register();
3402 scmi_sensors_register();
3403 scmi_voltage_register();
3404 scmi_system_register();
3405 scmi_powercap_register();
3406 scmi_pinctrl_register();
3407
3408 return platform_driver_register(&scmi_driver);
3409 }
3410 module_init(scmi_driver_init);
3411
scmi_driver_exit(void)3412 static void __exit scmi_driver_exit(void)
3413 {
3414 scmi_base_unregister();
3415
3416 scmi_clock_unregister();
3417 scmi_perf_unregister();
3418 scmi_power_unregister();
3419 scmi_reset_unregister();
3420 scmi_sensors_unregister();
3421 scmi_voltage_unregister();
3422 scmi_system_unregister();
3423 scmi_powercap_unregister();
3424 scmi_pinctrl_unregister();
3425
3426 platform_driver_unregister(&scmi_driver);
3427
3428 debugfs_remove_recursive(scmi_top_dentry);
3429 }
3430 module_exit(scmi_driver_exit);
3431
3432 MODULE_ALIAS("platform:arm-scmi");
3433 MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
3434 MODULE_DESCRIPTION("ARM SCMI protocol driver");
3435 MODULE_LICENSE("GPL v2");
3436