1 /*
2 * Copyright (C) ST-Ericsson SA 2010
3 * Author: Stefan Nilsson <stefan.xk.nilsson@stericsson.com> for ST-Ericsson.
4 * Author: Martin Persson <martin.persson@stericsson.com> for ST-Ericsson.
5 * License terms: GNU General Public License (GPL), version 2.
6 */
7
8 /*
9 * Mailbox nomenclature:
10 *
11 * APE MODEM
12 * mbox pairX
13 * ..........................
14 * . .
15 * . peer .
16 * . send ---- .
17 * . --> | | .
18 * . | | .
19 * . ---- .
20 * . .
21 * . local .
22 * . rec ---- .
23 * . | | <-- .
24 * . | | .
25 * . ---- .
26 * .........................
27 */
28
29 #include <linux/init.h>
30 #include <linux/module.h>
31 #include <linux/device.h>
32 #include <linux/interrupt.h>
33 #include <linux/spinlock.h>
34 #include <linux/errno.h>
35 #include <linux/io.h>
36 #include <linux/irq.h>
37 #include <linux/platform_device.h>
38 #include <linux/debugfs.h>
39 #include <linux/seq_file.h>
40 #include <linux/completion.h>
41 #include <mach/mbox-db5500.h>
42
43 #define MBOX_NAME "mbox"
44
45 #define MBOX_FIFO_DATA 0x000
46 #define MBOX_FIFO_ADD 0x004
47 #define MBOX_FIFO_REMOVE 0x008
48 #define MBOX_FIFO_THRES_FREE 0x00C
49 #define MBOX_FIFO_THRES_OCCUP 0x010
50 #define MBOX_FIFO_STATUS 0x014
51
52 #define MBOX_DISABLE_IRQ 0x4
53 #define MBOX_ENABLE_IRQ 0x0
54 #define MBOX_LATCH 1
55
56 /* Global list of all mailboxes */
57 static struct list_head mboxs = LIST_HEAD_INIT(mboxs);
58
get_mbox_with_id(u8 id)59 static struct mbox *get_mbox_with_id(u8 id)
60 {
61 u8 i;
62 struct list_head *pos = &mboxs;
63 for (i = 0; i <= id; i++)
64 pos = pos->next;
65
66 return (struct mbox *) list_entry(pos, struct mbox, list);
67 }
68
mbox_send(struct mbox * mbox,u32 mbox_msg,bool block)69 int mbox_send(struct mbox *mbox, u32 mbox_msg, bool block)
70 {
71 int res = 0;
72
73 spin_lock(&mbox->lock);
74
75 dev_dbg(&(mbox->pdev->dev),
76 "About to buffer 0x%X to mailbox 0x%X."
77 " ri = %d, wi = %d\n",
78 mbox_msg, (u32)mbox, mbox->read_index,
79 mbox->write_index);
80
81 /* Check if write buffer is full */
82 while (((mbox->write_index + 1) % MBOX_BUF_SIZE) == mbox->read_index) {
83 if (!block) {
84 dev_dbg(&(mbox->pdev->dev),
85 "Buffer full in non-blocking call! "
86 "Returning -ENOMEM!\n");
87 res = -ENOMEM;
88 goto exit;
89 }
90 spin_unlock(&mbox->lock);
91 dev_dbg(&(mbox->pdev->dev),
92 "Buffer full in blocking call! Sleeping...\n");
93 mbox->client_blocked = 1;
94 wait_for_completion(&mbox->buffer_available);
95 dev_dbg(&(mbox->pdev->dev),
96 "Blocking send was woken up! Trying again...\n");
97 spin_lock(&mbox->lock);
98 }
99
100 mbox->buffer[mbox->write_index] = mbox_msg;
101 mbox->write_index = (mbox->write_index + 1) % MBOX_BUF_SIZE;
102
103 /*
104 * Indicate that we want an IRQ as soon as there is a slot
105 * in the FIFO
106 */
107 writel(MBOX_ENABLE_IRQ, mbox->virtbase_peer + MBOX_FIFO_THRES_FREE);
108
109 exit:
110 spin_unlock(&mbox->lock);
111 return res;
112 }
113 EXPORT_SYMBOL(mbox_send);
114
115 #if defined(CONFIG_DEBUG_FS)
116 /*
117 * Expected input: <value> <nbr sends>
118 * Example: "echo 0xdeadbeef 4 > mbox-node" sends 0xdeadbeef 4 times
119 */
mbox_write_fifo(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)120 static ssize_t mbox_write_fifo(struct device *dev,
121 struct device_attribute *attr,
122 const char *buf,
123 size_t count)
124 {
125 unsigned long mbox_mess;
126 unsigned long nbr_sends;
127 unsigned long i;
128 char int_buf[16];
129 char *token;
130 char *val;
131
132 struct mbox *mbox = (struct mbox *) dev->platform_data;
133
134 strncpy((char *) &int_buf, buf, sizeof(int_buf));
135 token = (char *) &int_buf;
136
137 /* Parse message */
138 val = strsep(&token, " ");
139 if ((val == NULL) || (strict_strtoul(val, 16, &mbox_mess) != 0))
140 mbox_mess = 0xDEADBEEF;
141
142 val = strsep(&token, " ");
143 if ((val == NULL) || (strict_strtoul(val, 10, &nbr_sends) != 0))
144 nbr_sends = 1;
145
146 dev_dbg(dev, "Will write 0x%lX %ld times using data struct at 0x%X\n",
147 mbox_mess, nbr_sends, (u32) mbox);
148
149 for (i = 0; i < nbr_sends; i++)
150 mbox_send(mbox, mbox_mess, true);
151
152 return count;
153 }
154
mbox_read_fifo(struct device * dev,struct device_attribute * attr,char * buf)155 static ssize_t mbox_read_fifo(struct device *dev,
156 struct device_attribute *attr,
157 char *buf)
158 {
159 int mbox_value;
160 struct mbox *mbox = (struct mbox *) dev->platform_data;
161
162 if ((readl(mbox->virtbase_local + MBOX_FIFO_STATUS) & 0x7) <= 0)
163 return sprintf(buf, "Mailbox is empty\n");
164
165 mbox_value = readl(mbox->virtbase_local + MBOX_FIFO_DATA);
166 writel(MBOX_LATCH, (mbox->virtbase_local + MBOX_FIFO_REMOVE));
167
168 return sprintf(buf, "0x%X\n", mbox_value);
169 }
170
171 static DEVICE_ATTR(fifo, S_IWUGO | S_IRUGO, mbox_read_fifo, mbox_write_fifo);
172
mbox_show(struct seq_file * s,void * data)173 static int mbox_show(struct seq_file *s, void *data)
174 {
175 struct list_head *pos;
176 u8 mbox_index = 0;
177
178 list_for_each(pos, &mboxs) {
179 struct mbox *m =
180 (struct mbox *) list_entry(pos, struct mbox, list);
181 if (m == NULL) {
182 seq_printf(s,
183 "Unable to retrieve mailbox %d\n",
184 mbox_index);
185 continue;
186 }
187
188 spin_lock(&m->lock);
189 if ((m->virtbase_peer == NULL) || (m->virtbase_local == NULL)) {
190 seq_printf(s, "MAILBOX %d not setup or corrupt\n",
191 mbox_index);
192 spin_unlock(&m->lock);
193 continue;
194 }
195
196 seq_printf(s,
197 "===========================\n"
198 " MAILBOX %d\n"
199 " PEER MAILBOX DUMP\n"
200 "---------------------------\n"
201 "FIFO: 0x%X (%d)\n"
202 "Free Threshold: 0x%.2X (%d)\n"
203 "Occupied Threshold: 0x%.2X (%d)\n"
204 "Status: 0x%.2X (%d)\n"
205 " Free spaces (ot): %d (%d)\n"
206 " Occup spaces (ot): %d (%d)\n"
207 "===========================\n"
208 " LOCAL MAILBOX DUMP\n"
209 "---------------------------\n"
210 "FIFO: 0x%.X (%d)\n"
211 "Free Threshold: 0x%.2X (%d)\n"
212 "Occupied Threshold: 0x%.2X (%d)\n"
213 "Status: 0x%.2X (%d)\n"
214 " Free spaces (ot): %d (%d)\n"
215 " Occup spaces (ot): %d (%d)\n"
216 "===========================\n"
217 "write_index: %d\n"
218 "read_index : %d\n"
219 "===========================\n"
220 "\n",
221 mbox_index,
222 readl(m->virtbase_peer + MBOX_FIFO_DATA),
223 readl(m->virtbase_peer + MBOX_FIFO_DATA),
224 readl(m->virtbase_peer + MBOX_FIFO_THRES_FREE),
225 readl(m->virtbase_peer + MBOX_FIFO_THRES_FREE),
226 readl(m->virtbase_peer + MBOX_FIFO_THRES_OCCUP),
227 readl(m->virtbase_peer + MBOX_FIFO_THRES_OCCUP),
228 readl(m->virtbase_peer + MBOX_FIFO_STATUS),
229 readl(m->virtbase_peer + MBOX_FIFO_STATUS),
230 (readl(m->virtbase_peer + MBOX_FIFO_STATUS) >> 4) & 0x7,
231 (readl(m->virtbase_peer + MBOX_FIFO_STATUS) >> 7) & 0x1,
232 (readl(m->virtbase_peer + MBOX_FIFO_STATUS) >> 0) & 0x7,
233 (readl(m->virtbase_peer + MBOX_FIFO_STATUS) >> 3) & 0x1,
234 readl(m->virtbase_local + MBOX_FIFO_DATA),
235 readl(m->virtbase_local + MBOX_FIFO_DATA),
236 readl(m->virtbase_local + MBOX_FIFO_THRES_FREE),
237 readl(m->virtbase_local + MBOX_FIFO_THRES_FREE),
238 readl(m->virtbase_local + MBOX_FIFO_THRES_OCCUP),
239 readl(m->virtbase_local + MBOX_FIFO_THRES_OCCUP),
240 readl(m->virtbase_local + MBOX_FIFO_STATUS),
241 readl(m->virtbase_local + MBOX_FIFO_STATUS),
242 (readl(m->virtbase_local + MBOX_FIFO_STATUS) >> 4) & 0x7,
243 (readl(m->virtbase_local + MBOX_FIFO_STATUS) >> 7) & 0x1,
244 (readl(m->virtbase_local + MBOX_FIFO_STATUS) >> 0) & 0x7,
245 (readl(m->virtbase_local + MBOX_FIFO_STATUS) >> 3) & 0x1,
246 m->write_index, m->read_index);
247 mbox_index++;
248 spin_unlock(&m->lock);
249 }
250
251 return 0;
252 }
253
mbox_open(struct inode * inode,struct file * file)254 static int mbox_open(struct inode *inode, struct file *file)
255 {
256 return single_open(file, mbox_show, NULL);
257 }
258
259 static const struct file_operations mbox_operations = {
260 .owner = THIS_MODULE,
261 .open = mbox_open,
262 .read = seq_read,
263 .llseek = seq_lseek,
264 .release = single_release,
265 };
266 #endif
267
mbox_irq(int irq,void * arg)268 static irqreturn_t mbox_irq(int irq, void *arg)
269 {
270 u32 mbox_value;
271 int nbr_occup;
272 int nbr_free;
273 struct mbox *mbox = (struct mbox *) arg;
274
275 spin_lock(&mbox->lock);
276
277 dev_dbg(&(mbox->pdev->dev),
278 "mbox IRQ [%d] received. ri = %d, wi = %d\n",
279 irq, mbox->read_index, mbox->write_index);
280
281 /*
282 * Check if we have any outgoing messages, and if there is space for
283 * them in the FIFO.
284 */
285 if (mbox->read_index != mbox->write_index) {
286 /*
287 * Check by reading FREE for LOCAL since that indicates
288 * OCCUP for PEER
289 */
290 nbr_free = (readl(mbox->virtbase_local + MBOX_FIFO_STATUS)
291 >> 4) & 0x7;
292 dev_dbg(&(mbox->pdev->dev),
293 "Status indicates %d empty spaces in the FIFO!\n",
294 nbr_free);
295
296 while ((nbr_free > 0) &&
297 (mbox->read_index != mbox->write_index)) {
298 /* Write the message and latch it into the FIFO */
299 writel(mbox->buffer[mbox->read_index],
300 (mbox->virtbase_peer + MBOX_FIFO_DATA));
301 writel(MBOX_LATCH,
302 (mbox->virtbase_peer + MBOX_FIFO_ADD));
303 dev_dbg(&(mbox->pdev->dev),
304 "Wrote message 0x%X to addr 0x%X\n",
305 mbox->buffer[mbox->read_index],
306 (u32) (mbox->virtbase_peer + MBOX_FIFO_DATA));
307
308 nbr_free--;
309 mbox->read_index =
310 (mbox->read_index + 1) % MBOX_BUF_SIZE;
311 }
312
313 /*
314 * Check if we still want IRQ:s when there is free
315 * space to send
316 */
317 if (mbox->read_index != mbox->write_index) {
318 dev_dbg(&(mbox->pdev->dev),
319 "Still have messages to send, but FIFO full. "
320 "Request IRQ again!\n");
321 writel(MBOX_ENABLE_IRQ,
322 mbox->virtbase_peer + MBOX_FIFO_THRES_FREE);
323 } else {
324 dev_dbg(&(mbox->pdev->dev),
325 "No more messages to send. "
326 "Do not request IRQ again!\n");
327 writel(MBOX_DISABLE_IRQ,
328 mbox->virtbase_peer + MBOX_FIFO_THRES_FREE);
329 }
330
331 /*
332 * Check if we can signal any blocked clients that it is OK to
333 * start buffering again
334 */
335 if (mbox->client_blocked &&
336 (((mbox->write_index + 1) % MBOX_BUF_SIZE)
337 != mbox->read_index)) {
338 dev_dbg(&(mbox->pdev->dev),
339 "Waking up blocked client\n");
340 complete(&mbox->buffer_available);
341 mbox->client_blocked = 0;
342 }
343 }
344
345 /* Check if we have any incoming messages */
346 nbr_occup = readl(mbox->virtbase_local + MBOX_FIFO_STATUS) & 0x7;
347 if (nbr_occup == 0)
348 goto exit;
349
350 if (mbox->cb == NULL) {
351 dev_dbg(&(mbox->pdev->dev), "No receive callback registered, "
352 "leaving %d incoming messages in fifo!\n", nbr_occup);
353 goto exit;
354 }
355
356 /* Read and acknowledge the message */
357 mbox_value = readl(mbox->virtbase_local + MBOX_FIFO_DATA);
358 writel(MBOX_LATCH, (mbox->virtbase_local + MBOX_FIFO_REMOVE));
359
360 /* Notify consumer of new mailbox message */
361 dev_dbg(&(mbox->pdev->dev), "Calling callback for message 0x%X!\n",
362 mbox_value);
363 mbox->cb(mbox_value, mbox->client_data);
364
365 exit:
366 dev_dbg(&(mbox->pdev->dev), "Exit mbox IRQ. ri = %d, wi = %d\n",
367 mbox->read_index, mbox->write_index);
368 spin_unlock(&mbox->lock);
369
370 return IRQ_HANDLED;
371 }
372
373 /* Setup is executed once for each mbox pair */
mbox_setup(u8 mbox_id,mbox_recv_cb_t * mbox_cb,void * priv)374 struct mbox *mbox_setup(u8 mbox_id, mbox_recv_cb_t *mbox_cb, void *priv)
375 {
376 struct resource *resource;
377 int irq;
378 int res;
379 struct mbox *mbox;
380
381 mbox = get_mbox_with_id(mbox_id);
382 if (mbox == NULL) {
383 dev_err(&(mbox->pdev->dev), "Incorrect mailbox id: %d!\n",
384 mbox_id);
385 goto exit;
386 }
387
388 /*
389 * Check if mailbox has been allocated to someone else,
390 * otherwise allocate it
391 */
392 if (mbox->allocated) {
393 dev_err(&(mbox->pdev->dev), "Mailbox number %d is busy!\n",
394 mbox_id);
395 mbox = NULL;
396 goto exit;
397 }
398 mbox->allocated = true;
399
400 dev_dbg(&(mbox->pdev->dev), "Initiating mailbox number %d: 0x%X...\n",
401 mbox_id, (u32)mbox);
402
403 mbox->client_data = priv;
404 mbox->cb = mbox_cb;
405
406 /* Get addr for peer mailbox and ioremap it */
407 resource = platform_get_resource_byname(mbox->pdev,
408 IORESOURCE_MEM,
409 "mbox_peer");
410 if (resource == NULL) {
411 dev_err(&(mbox->pdev->dev),
412 "Unable to retrieve mbox peer resource\n");
413 mbox = NULL;
414 goto exit;
415 }
416 dev_dbg(&(mbox->pdev->dev),
417 "Resource name: %s start: 0x%X, end: 0x%X\n",
418 resource->name, resource->start, resource->end);
419 mbox->virtbase_peer = ioremap(resource->start, resource_size(resource));
420 if (!mbox->virtbase_peer) {
421 dev_err(&(mbox->pdev->dev), "Unable to ioremap peer mbox\n");
422 mbox = NULL;
423 goto exit;
424 }
425 dev_dbg(&(mbox->pdev->dev),
426 "ioremapped peer physical: (0x%X-0x%X) to virtual: 0x%X\n",
427 resource->start, resource->end, (u32) mbox->virtbase_peer);
428
429 /* Get addr for local mailbox and ioremap it */
430 resource = platform_get_resource_byname(mbox->pdev,
431 IORESOURCE_MEM,
432 "mbox_local");
433 if (resource == NULL) {
434 dev_err(&(mbox->pdev->dev),
435 "Unable to retrieve mbox local resource\n");
436 mbox = NULL;
437 goto exit;
438 }
439 dev_dbg(&(mbox->pdev->dev),
440 "Resource name: %s start: 0x%X, end: 0x%X\n",
441 resource->name, resource->start, resource->end);
442 mbox->virtbase_local = ioremap(resource->start, resource_size(resource));
443 if (!mbox->virtbase_local) {
444 dev_err(&(mbox->pdev->dev), "Unable to ioremap local mbox\n");
445 mbox = NULL;
446 goto exit;
447 }
448 dev_dbg(&(mbox->pdev->dev),
449 "ioremapped local physical: (0x%X-0x%X) to virtual: 0x%X\n",
450 resource->start, resource->end, (u32) mbox->virtbase_peer);
451
452 init_completion(&mbox->buffer_available);
453 mbox->client_blocked = 0;
454
455 /* Get IRQ for mailbox and allocate it */
456 irq = platform_get_irq_byname(mbox->pdev, "mbox_irq");
457 if (irq < 0) {
458 dev_err(&(mbox->pdev->dev),
459 "Unable to retrieve mbox irq resource\n");
460 mbox = NULL;
461 goto exit;
462 }
463
464 dev_dbg(&(mbox->pdev->dev), "Allocating irq %d...\n", irq);
465 res = request_irq(irq, mbox_irq, 0, mbox->name, (void *) mbox);
466 if (res < 0) {
467 dev_err(&(mbox->pdev->dev),
468 "Unable to allocate mbox irq %d\n", irq);
469 mbox = NULL;
470 goto exit;
471 }
472
473 /* Set up mailbox to not launch IRQ on free space in mailbox */
474 writel(MBOX_DISABLE_IRQ, mbox->virtbase_peer + MBOX_FIFO_THRES_FREE);
475
476 /*
477 * Set up mailbox to launch IRQ on new message if we have
478 * a callback set. If not, do not raise IRQ, but keep message
479 * in FIFO for manual retrieval
480 */
481 if (mbox_cb != NULL)
482 writel(MBOX_ENABLE_IRQ,
483 mbox->virtbase_local + MBOX_FIFO_THRES_OCCUP);
484 else
485 writel(MBOX_DISABLE_IRQ,
486 mbox->virtbase_local + MBOX_FIFO_THRES_OCCUP);
487
488 #if defined(CONFIG_DEBUG_FS)
489 res = device_create_file(&(mbox->pdev->dev), &dev_attr_fifo);
490 if (res != 0)
491 dev_warn(&(mbox->pdev->dev),
492 "Unable to create mbox sysfs entry");
493
494 (void) debugfs_create_file("mbox", S_IFREG | S_IRUGO, NULL,
495 NULL, &mbox_operations);
496 #endif
497
498 dev_info(&(mbox->pdev->dev),
499 "Mailbox driver with index %d initiated!\n", mbox_id);
500
501 exit:
502 return mbox;
503 }
504 EXPORT_SYMBOL(mbox_setup);
505
506
mbox_probe(struct platform_device * pdev)507 int __init mbox_probe(struct platform_device *pdev)
508 {
509 struct mbox local_mbox;
510 struct mbox *mbox;
511 int res = 0;
512 dev_dbg(&(pdev->dev), "Probing mailbox (pdev = 0x%X)...\n", (u32) pdev);
513
514 memset(&local_mbox, 0x0, sizeof(struct mbox));
515
516 /* Associate our mbox data with the platform device */
517 res = platform_device_add_data(pdev,
518 (void *) &local_mbox,
519 sizeof(struct mbox));
520 if (res != 0) {
521 dev_err(&(pdev->dev),
522 "Unable to allocate driver platform data!\n");
523 goto exit;
524 }
525
526 mbox = (struct mbox *) pdev->dev.platform_data;
527 mbox->pdev = pdev;
528 mbox->write_index = 0;
529 mbox->read_index = 0;
530
531 INIT_LIST_HEAD(&(mbox->list));
532 list_add_tail(&(mbox->list), &mboxs);
533
534 sprintf(mbox->name, "%s", MBOX_NAME);
535 spin_lock_init(&mbox->lock);
536
537 dev_info(&(pdev->dev), "Mailbox driver loaded\n");
538
539 exit:
540 return res;
541 }
542
543 static struct platform_driver mbox_driver = {
544 .driver = {
545 .name = MBOX_NAME,
546 .owner = THIS_MODULE,
547 },
548 };
549
mbox_init(void)550 static int __init mbox_init(void)
551 {
552 return platform_driver_probe(&mbox_driver, mbox_probe);
553 }
554
555 module_init(mbox_init);
556
mbox_exit(void)557 void __exit mbox_exit(void)
558 {
559 platform_driver_unregister(&mbox_driver);
560 }
561
562 module_exit(mbox_exit);
563
564 MODULE_LICENSE("GPL");
565 MODULE_DESCRIPTION("MBOX driver");
566