1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * otg_fsm.c - ChipIdea USB IP core OTG FSM driver
4  *
5  * Copyright (C) 2014 Freescale Semiconductor, Inc.
6  *
7  * Author: Jun Li
8  */
9 
10 /*
11  * This file mainly handles OTG fsm, it includes OTG fsm operations
12  * for HNP and SRP.
13  *
14  * TODO List
15  * - ADP
16  * - OTG test device
17  */
18 
19 #include <linux/usb/otg.h>
20 #include <linux/usb/gadget.h>
21 #include <linux/usb/hcd.h>
22 #include <linux/usb/chipidea.h>
23 #include <linux/regulator/consumer.h>
24 
25 #include "ci.h"
26 #include "bits.h"
27 #include "otg.h"
28 #include "otg_fsm.h"
29 
30 /* Add for otg: interact with user space app */
31 static ssize_t
32 a_bus_req_show(struct device *dev, struct device_attribute *attr, char *buf)
33 {
34 	char		*next;
35 	unsigned	size, t;
36 	struct ci_hdrc	*ci = dev_get_drvdata(dev);
37 
38 	next = buf;
39 	size = PAGE_SIZE;
40 	t = scnprintf(next, size, "%d\n", ci->fsm.a_bus_req);
41 	size -= t;
42 	next += t;
43 
44 	return PAGE_SIZE - size;
45 }
46 
47 static ssize_t
48 a_bus_req_store(struct device *dev, struct device_attribute *attr,
49 					const char *buf, size_t count)
50 {
51 	struct ci_hdrc *ci = dev_get_drvdata(dev);
52 
53 	if (count > 2)
54 		return -1;
55 
56 	mutex_lock(&ci->fsm.lock);
57 	if (buf[0] == '0') {
58 		ci->fsm.a_bus_req = 0;
59 	} else if (buf[0] == '1') {
60 		/* If a_bus_drop is TRUE, a_bus_req can't be set */
61 		if (ci->fsm.a_bus_drop) {
62 			mutex_unlock(&ci->fsm.lock);
63 			return count;
64 		}
65 		ci->fsm.a_bus_req = 1;
66 		if (ci->fsm.otg->state == OTG_STATE_A_PERIPHERAL) {
67 			ci->gadget.host_request_flag = 1;
68 			mutex_unlock(&ci->fsm.lock);
69 			return count;
70 		}
71 	}
72 
73 	ci_otg_queue_work(ci);
74 	mutex_unlock(&ci->fsm.lock);
75 
76 	return count;
77 }
78 static DEVICE_ATTR_RW(a_bus_req);
79 
80 static ssize_t
81 a_bus_drop_show(struct device *dev, struct device_attribute *attr, char *buf)
82 {
83 	char		*next;
84 	unsigned	size, t;
85 	struct ci_hdrc	*ci = dev_get_drvdata(dev);
86 
87 	next = buf;
88 	size = PAGE_SIZE;
89 	t = scnprintf(next, size, "%d\n", ci->fsm.a_bus_drop);
90 	size -= t;
91 	next += t;
92 
93 	return PAGE_SIZE - size;
94 }
95 
96 static ssize_t
97 a_bus_drop_store(struct device *dev, struct device_attribute *attr,
98 					const char *buf, size_t count)
99 {
100 	struct ci_hdrc	*ci = dev_get_drvdata(dev);
101 
102 	if (count > 2)
103 		return -1;
104 
105 	mutex_lock(&ci->fsm.lock);
106 	if (buf[0] == '0') {
107 		ci->fsm.a_bus_drop = 0;
108 	} else if (buf[0] == '1') {
109 		ci->fsm.a_bus_drop = 1;
110 		ci->fsm.a_bus_req = 0;
111 	}
112 
113 	ci_otg_queue_work(ci);
114 	mutex_unlock(&ci->fsm.lock);
115 
116 	return count;
117 }
118 static DEVICE_ATTR_RW(a_bus_drop);
119 
120 static ssize_t
121 b_bus_req_show(struct device *dev, struct device_attribute *attr, char *buf)
122 {
123 	char		*next;
124 	unsigned	size, t;
125 	struct ci_hdrc	*ci = dev_get_drvdata(dev);
126 
127 	next = buf;
128 	size = PAGE_SIZE;
129 	t = scnprintf(next, size, "%d\n", ci->fsm.b_bus_req);
130 	size -= t;
131 	next += t;
132 
133 	return PAGE_SIZE - size;
134 }
135 
136 static ssize_t
137 b_bus_req_store(struct device *dev, struct device_attribute *attr,
138 					const char *buf, size_t count)
139 {
140 	struct ci_hdrc	*ci = dev_get_drvdata(dev);
141 
142 	if (count > 2)
143 		return -1;
144 
145 	mutex_lock(&ci->fsm.lock);
146 	if (buf[0] == '0')
147 		ci->fsm.b_bus_req = 0;
148 	else if (buf[0] == '1') {
149 		ci->fsm.b_bus_req = 1;
150 		if (ci->fsm.otg->state == OTG_STATE_B_PERIPHERAL) {
151 			ci->gadget.host_request_flag = 1;
152 			mutex_unlock(&ci->fsm.lock);
153 			return count;
154 		}
155 	}
156 
157 	ci_otg_queue_work(ci);
158 	mutex_unlock(&ci->fsm.lock);
159 
160 	return count;
161 }
162 static DEVICE_ATTR_RW(b_bus_req);
163 
164 static ssize_t
165 a_clr_err_store(struct device *dev, struct device_attribute *attr,
166 					const char *buf, size_t count)
167 {
168 	struct ci_hdrc	*ci = dev_get_drvdata(dev);
169 
170 	if (count > 2)
171 		return -1;
172 
173 	mutex_lock(&ci->fsm.lock);
174 	if (buf[0] == '1')
175 		ci->fsm.a_clr_err = 1;
176 
177 	ci_otg_queue_work(ci);
178 	mutex_unlock(&ci->fsm.lock);
179 
180 	return count;
181 }
182 static DEVICE_ATTR_WO(a_clr_err);
183 
184 static struct attribute *inputs_attrs[] = {
185 	&dev_attr_a_bus_req.attr,
186 	&dev_attr_a_bus_drop.attr,
187 	&dev_attr_b_bus_req.attr,
188 	&dev_attr_a_clr_err.attr,
189 	NULL,
190 };
191 
192 static const struct attribute_group inputs_attr_group = {
193 	.name = "inputs",
194 	.attrs = inputs_attrs,
195 };
196 
197 /*
198  * Keep this list in the same order as timers indexed
199  * by enum otg_fsm_timer in include/linux/usb/otg-fsm.h
200  */
201 static unsigned otg_timer_ms[] = {
202 	TA_WAIT_VRISE,
203 	TA_WAIT_VFALL,
204 	TA_WAIT_BCON,
205 	TA_AIDL_BDIS,
206 	TB_ASE0_BRST,
207 	TA_BIDL_ADIS,
208 	TB_AIDL_BDIS,
209 	TB_SE0_SRP,
210 	TB_SRP_FAIL,
211 	0,
212 	TB_DATA_PLS,
213 	TB_SSEND_SRP,
214 };
215 
216 /*
217  * Add timer to active timer list
218  */
219 static void ci_otg_add_timer(struct ci_hdrc *ci, enum otg_fsm_timer t)
220 {
221 	unsigned long flags, timer_sec, timer_nsec;
222 
223 	if (t >= NUM_OTG_FSM_TIMERS)
224 		return;
225 
226 	spin_lock_irqsave(&ci->lock, flags);
227 	timer_sec = otg_timer_ms[t] / MSEC_PER_SEC;
228 	timer_nsec = (otg_timer_ms[t] % MSEC_PER_SEC) * NSEC_PER_MSEC;
229 	ci->hr_timeouts[t] = ktime_add(ktime_get(),
230 				ktime_set(timer_sec, timer_nsec));
231 	ci->enabled_otg_timer_bits |= (1 << t);
232 	if ((ci->next_otg_timer == NUM_OTG_FSM_TIMERS) ||
233 			ktime_after(ci->hr_timeouts[ci->next_otg_timer],
234 						ci->hr_timeouts[t])) {
235 			ci->next_otg_timer = t;
236 			hrtimer_start_range_ns(&ci->otg_fsm_hrtimer,
237 					ci->hr_timeouts[t], NSEC_PER_MSEC,
238 							HRTIMER_MODE_ABS);
239 	}
240 	spin_unlock_irqrestore(&ci->lock, flags);
241 }
242 
243 /*
244  * Remove timer from active timer list
245  */
246 static void ci_otg_del_timer(struct ci_hdrc *ci, enum otg_fsm_timer t)
247 {
248 	unsigned long flags, enabled_timer_bits;
249 	enum otg_fsm_timer cur_timer, next_timer = NUM_OTG_FSM_TIMERS;
250 
251 	if ((t >= NUM_OTG_FSM_TIMERS) ||
252 			!(ci->enabled_otg_timer_bits & (1 << t)))
253 		return;
254 
255 	spin_lock_irqsave(&ci->lock, flags);
256 	ci->enabled_otg_timer_bits &= ~(1 << t);
257 	if (ci->next_otg_timer == t) {
258 		if (ci->enabled_otg_timer_bits == 0) {
259 			spin_unlock_irqrestore(&ci->lock, flags);
260 			/* No enabled timers after delete it */
261 			hrtimer_cancel(&ci->otg_fsm_hrtimer);
262 			spin_lock_irqsave(&ci->lock, flags);
263 			ci->next_otg_timer = NUM_OTG_FSM_TIMERS;
264 		} else {
265 			/* Find the next timer */
266 			enabled_timer_bits = ci->enabled_otg_timer_bits;
267 			for_each_set_bit(cur_timer, &enabled_timer_bits,
268 							NUM_OTG_FSM_TIMERS) {
269 				if ((next_timer == NUM_OTG_FSM_TIMERS) ||
270 					ktime_before(ci->hr_timeouts[next_timer],
271 					 ci->hr_timeouts[cur_timer]))
272 					next_timer = cur_timer;
273 			}
274 		}
275 	}
276 	if (next_timer != NUM_OTG_FSM_TIMERS) {
277 		ci->next_otg_timer = next_timer;
278 		hrtimer_start_range_ns(&ci->otg_fsm_hrtimer,
279 			ci->hr_timeouts[next_timer], NSEC_PER_MSEC,
280 							HRTIMER_MODE_ABS);
281 	}
282 	spin_unlock_irqrestore(&ci->lock, flags);
283 }
284 
285 /* OTG FSM timer handlers */
286 static int a_wait_vrise_tmout(struct ci_hdrc *ci)
287 {
288 	ci->fsm.a_wait_vrise_tmout = 1;
289 	return 0;
290 }
291 
292 static int a_wait_vfall_tmout(struct ci_hdrc *ci)
293 {
294 	ci->fsm.a_wait_vfall_tmout = 1;
295 	return 0;
296 }
297 
298 static int a_wait_bcon_tmout(struct ci_hdrc *ci)
299 {
300 	ci->fsm.a_wait_bcon_tmout = 1;
301 	return 0;
302 }
303 
304 static int a_aidl_bdis_tmout(struct ci_hdrc *ci)
305 {
306 	ci->fsm.a_aidl_bdis_tmout = 1;
307 	return 0;
308 }
309 
310 static int b_ase0_brst_tmout(struct ci_hdrc *ci)
311 {
312 	ci->fsm.b_ase0_brst_tmout = 1;
313 	return 0;
314 }
315 
316 static int a_bidl_adis_tmout(struct ci_hdrc *ci)
317 {
318 	ci->fsm.a_bidl_adis_tmout = 1;
319 	return 0;
320 }
321 
322 static int b_aidl_bdis_tmout(struct ci_hdrc *ci)
323 {
324 	ci->fsm.a_bus_suspend = 1;
325 	return 0;
326 }
327 
328 static int b_se0_srp_tmout(struct ci_hdrc *ci)
329 {
330 	ci->fsm.b_se0_srp = 1;
331 	return 0;
332 }
333 
334 static int b_srp_fail_tmout(struct ci_hdrc *ci)
335 {
336 	ci->fsm.b_srp_done = 1;
337 	return 1;
338 }
339 
340 static int b_data_pls_tmout(struct ci_hdrc *ci)
341 {
342 	ci->fsm.b_srp_done = 1;
343 	ci->fsm.b_bus_req = 0;
344 	if (ci->fsm.power_up)
345 		ci->fsm.power_up = 0;
346 	hw_write_otgsc(ci, OTGSC_HABA, 0);
347 	pm_runtime_put(ci->dev);
348 	return 0;
349 }
350 
351 static int b_ssend_srp_tmout(struct ci_hdrc *ci)
352 {
353 	ci->fsm.b_ssend_srp = 1;
354 	/* only vbus fall below B_sess_vld in b_idle state */
355 	if (ci->fsm.otg->state == OTG_STATE_B_IDLE)
356 		return 0;
357 	else
358 		return 1;
359 }
360 
361 /*
362  * Keep this list in the same order as timers indexed
363  * by enum otg_fsm_timer in include/linux/usb/otg-fsm.h
364  */
365 static int (*otg_timer_handlers[])(struct ci_hdrc *) = {
366 	a_wait_vrise_tmout,	/* A_WAIT_VRISE */
367 	a_wait_vfall_tmout,	/* A_WAIT_VFALL */
368 	a_wait_bcon_tmout,	/* A_WAIT_BCON */
369 	a_aidl_bdis_tmout,	/* A_AIDL_BDIS */
370 	b_ase0_brst_tmout,	/* B_ASE0_BRST */
371 	a_bidl_adis_tmout,	/* A_BIDL_ADIS */
372 	b_aidl_bdis_tmout,	/* B_AIDL_BDIS */
373 	b_se0_srp_tmout,	/* B_SE0_SRP */
374 	b_srp_fail_tmout,	/* B_SRP_FAIL */
375 	NULL,			/* A_WAIT_ENUM */
376 	b_data_pls_tmout,	/* B_DATA_PLS */
377 	b_ssend_srp_tmout,	/* B_SSEND_SRP */
378 };
379 
380 /*
381  * Enable the next nearest enabled timer if have
382  */
383 static enum hrtimer_restart ci_otg_hrtimer_func(struct hrtimer *t)
384 {
385 	struct ci_hdrc *ci = container_of(t, struct ci_hdrc, otg_fsm_hrtimer);
386 	ktime_t	now, *timeout;
387 	unsigned long   enabled_timer_bits;
388 	unsigned long   flags;
389 	enum otg_fsm_timer cur_timer, next_timer = NUM_OTG_FSM_TIMERS;
390 	int ret = -EINVAL;
391 
392 	spin_lock_irqsave(&ci->lock, flags);
393 	enabled_timer_bits = ci->enabled_otg_timer_bits;
394 	ci->next_otg_timer = NUM_OTG_FSM_TIMERS;
395 
396 	now = ktime_get();
397 	for_each_set_bit(cur_timer, &enabled_timer_bits, NUM_OTG_FSM_TIMERS) {
398 		if (ktime_compare(now, ci->hr_timeouts[cur_timer]) >= 0) {
399 			ci->enabled_otg_timer_bits &= ~(1 << cur_timer);
400 			if (otg_timer_handlers[cur_timer])
401 				ret = otg_timer_handlers[cur_timer](ci);
402 		} else {
403 			if ((next_timer == NUM_OTG_FSM_TIMERS) ||
404 				ktime_before(ci->hr_timeouts[cur_timer],
405 					ci->hr_timeouts[next_timer]))
406 				next_timer = cur_timer;
407 		}
408 	}
409 	/* Enable the next nearest timer */
410 	if (next_timer < NUM_OTG_FSM_TIMERS) {
411 		timeout = &ci->hr_timeouts[next_timer];
412 		hrtimer_start_range_ns(&ci->otg_fsm_hrtimer, *timeout,
413 					NSEC_PER_MSEC, HRTIMER_MODE_ABS);
414 		ci->next_otg_timer = next_timer;
415 	}
416 	spin_unlock_irqrestore(&ci->lock, flags);
417 
418 	if (!ret)
419 		ci_otg_queue_work(ci);
420 
421 	return HRTIMER_NORESTART;
422 }
423 
424 /* Initialize timers */
425 static int ci_otg_init_timers(struct ci_hdrc *ci)
426 {
427 	hrtimer_setup(&ci->otg_fsm_hrtimer, ci_otg_hrtimer_func, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
428 
429 	return 0;
430 }
431 
432 /* -------------------------------------------------------------*/
433 /* Operations that will be called from OTG Finite State Machine */
434 /* -------------------------------------------------------------*/
435 static void ci_otg_fsm_add_timer(struct otg_fsm *fsm, enum otg_fsm_timer t)
436 {
437 	struct ci_hdrc	*ci = container_of(fsm, struct ci_hdrc, fsm);
438 
439 	if (t < NUM_OTG_FSM_TIMERS)
440 		ci_otg_add_timer(ci, t);
441 	return;
442 }
443 
444 static void ci_otg_fsm_del_timer(struct otg_fsm *fsm, enum otg_fsm_timer t)
445 {
446 	struct ci_hdrc	*ci = container_of(fsm, struct ci_hdrc, fsm);
447 
448 	if (t < NUM_OTG_FSM_TIMERS)
449 		ci_otg_del_timer(ci, t);
450 	return;
451 }
452 
453 /*
454  * A-device drive vbus: turn on vbus regulator and enable port power
455  * Data pulse irq should be disabled while vbus is on.
456  */
457 static void ci_otg_drv_vbus(struct otg_fsm *fsm, int on)
458 {
459 	int ret;
460 	struct ci_hdrc	*ci = container_of(fsm, struct ci_hdrc, fsm);
461 
462 	if (on) {
463 		/* Enable power */
464 		hw_write(ci, OP_PORTSC, PORTSC_W1C_BITS | PORTSC_PP,
465 							PORTSC_PP);
466 		if (ci->platdata->reg_vbus) {
467 			ret = regulator_enable(ci->platdata->reg_vbus);
468 			if (ret) {
469 				dev_err(ci->dev,
470 				"Failed to enable vbus regulator, ret=%d\n",
471 				ret);
472 				return;
473 			}
474 		}
475 
476 		if (ci->platdata->flags & CI_HDRC_PHY_VBUS_CONTROL)
477 			usb_phy_vbus_on(ci->usb_phy);
478 
479 		/* Disable data pulse irq */
480 		hw_write_otgsc(ci, OTGSC_DPIE, 0);
481 
482 		fsm->a_srp_det = 0;
483 		fsm->power_up = 0;
484 	} else {
485 		if (ci->platdata->reg_vbus)
486 			regulator_disable(ci->platdata->reg_vbus);
487 
488 		if (ci->platdata->flags & CI_HDRC_PHY_VBUS_CONTROL)
489 			usb_phy_vbus_off(ci->usb_phy);
490 
491 		fsm->a_bus_drop = 1;
492 		fsm->a_bus_req = 0;
493 	}
494 }
495 
496 /*
497  * Control data line by Run Stop bit.
498  */
499 static void ci_otg_loc_conn(struct otg_fsm *fsm, int on)
500 {
501 	struct ci_hdrc	*ci = container_of(fsm, struct ci_hdrc, fsm);
502 
503 	if (on)
504 		hw_write(ci, OP_USBCMD, USBCMD_RS, USBCMD_RS);
505 	else
506 		hw_write(ci, OP_USBCMD, USBCMD_RS, 0);
507 }
508 
509 /*
510  * Generate SOF by host.
511  * In host mode, controller will automatically send SOF.
512  * Suspend will block the data on the port.
513  *
514  * This is controlled through usbcore by usb autosuspend,
515  * so the usb device class driver need support autosuspend,
516  * otherwise the bus suspend will not happen.
517  */
518 static void ci_otg_loc_sof(struct otg_fsm *fsm, int on)
519 {
520 	struct usb_device *udev;
521 
522 	if (!fsm->otg->host)
523 		return;
524 
525 	udev = usb_hub_find_child(fsm->otg->host->root_hub, 1);
526 	if (!udev)
527 		return;
528 
529 	if (on) {
530 		usb_disable_autosuspend(udev);
531 	} else {
532 		pm_runtime_set_autosuspend_delay(&udev->dev, 0);
533 		usb_enable_autosuspend(udev);
534 	}
535 }
536 
537 /*
538  * Start SRP pulsing by data-line pulsing,
539  * no v-bus pulsing followed
540  */
541 static void ci_otg_start_pulse(struct otg_fsm *fsm)
542 {
543 	struct ci_hdrc	*ci = container_of(fsm, struct ci_hdrc, fsm);
544 
545 	/* Hardware Assistant Data pulse */
546 	hw_write_otgsc(ci, OTGSC_HADP, OTGSC_HADP);
547 
548 	pm_runtime_get(ci->dev);
549 	ci_otg_add_timer(ci, B_DATA_PLS);
550 }
551 
552 static int ci_otg_start_host(struct otg_fsm *fsm, int on)
553 {
554 	struct ci_hdrc	*ci = container_of(fsm, struct ci_hdrc, fsm);
555 
556 	if (on) {
557 		ci_role_stop(ci);
558 		ci_role_start(ci, CI_ROLE_HOST);
559 	} else {
560 		ci_role_stop(ci);
561 		ci_role_start(ci, CI_ROLE_GADGET);
562 	}
563 	return 0;
564 }
565 
566 static int ci_otg_start_gadget(struct otg_fsm *fsm, int on)
567 {
568 	struct ci_hdrc	*ci = container_of(fsm, struct ci_hdrc, fsm);
569 
570 	if (on)
571 		usb_gadget_vbus_connect(&ci->gadget);
572 	else
573 		usb_gadget_vbus_disconnect(&ci->gadget);
574 
575 	return 0;
576 }
577 
578 static struct otg_fsm_ops ci_otg_ops = {
579 	.drv_vbus = ci_otg_drv_vbus,
580 	.loc_conn = ci_otg_loc_conn,
581 	.loc_sof = ci_otg_loc_sof,
582 	.start_pulse = ci_otg_start_pulse,
583 	.add_timer = ci_otg_fsm_add_timer,
584 	.del_timer = ci_otg_fsm_del_timer,
585 	.start_host = ci_otg_start_host,
586 	.start_gadget = ci_otg_start_gadget,
587 };
588 
589 int ci_otg_fsm_work(struct ci_hdrc *ci)
590 {
591 	/*
592 	 * Don't do fsm transition for B device
593 	 * when there is no gadget class driver
594 	 */
595 	if (ci->fsm.id && !(ci->driver) &&
596 		ci->fsm.otg->state < OTG_STATE_A_IDLE)
597 		return 0;
598 
599 	pm_runtime_get_sync(ci->dev);
600 	if (otg_statemachine(&ci->fsm)) {
601 		if (ci->fsm.otg->state == OTG_STATE_A_IDLE) {
602 			/*
603 			 * Further state change for cases:
604 			 * a_idle to b_idle; or
605 			 * a_idle to a_wait_vrise due to ID change(1->0), so
606 			 * B-dev becomes A-dev can try to start new session
607 			 * consequently; or
608 			 * a_idle to a_wait_vrise when power up
609 			 */
610 			if ((ci->fsm.id) || (ci->id_event) ||
611 						(ci->fsm.power_up)) {
612 				ci_otg_queue_work(ci);
613 			} else {
614 				/* Enable data pulse irq */
615 				hw_write(ci, OP_PORTSC, PORTSC_W1C_BITS |
616 								PORTSC_PP, 0);
617 				hw_write_otgsc(ci, OTGSC_DPIS, OTGSC_DPIS);
618 				hw_write_otgsc(ci, OTGSC_DPIE, OTGSC_DPIE);
619 			}
620 			if (ci->id_event)
621 				ci->id_event = false;
622 		} else if (ci->fsm.otg->state == OTG_STATE_B_IDLE) {
623 			if (ci->fsm.b_sess_vld) {
624 				ci->fsm.power_up = 0;
625 				/*
626 				 * Further transite to b_periphearl state
627 				 * when register gadget driver with vbus on
628 				 */
629 				ci_otg_queue_work(ci);
630 			}
631 		} else if (ci->fsm.otg->state == OTG_STATE_A_HOST) {
632 			pm_runtime_mark_last_busy(ci->dev);
633 			pm_runtime_put_autosuspend(ci->dev);
634 			return 0;
635 		}
636 	}
637 	pm_runtime_put_sync(ci->dev);
638 	return 0;
639 }
640 
641 /*
642  * Update fsm variables in each state if catching expected interrupts,
643  * called by otg fsm isr.
644  */
645 static void ci_otg_fsm_event(struct ci_hdrc *ci)
646 {
647 	u32 intr_sts, otg_bsess_vld, port_conn;
648 	struct otg_fsm *fsm = &ci->fsm;
649 
650 	intr_sts = hw_read_intr_status(ci);
651 	otg_bsess_vld = hw_read_otgsc(ci, OTGSC_BSV);
652 	port_conn = hw_read(ci, OP_PORTSC, PORTSC_CCS);
653 
654 	switch (ci->fsm.otg->state) {
655 	case OTG_STATE_A_WAIT_BCON:
656 		if (port_conn) {
657 			fsm->b_conn = 1;
658 			fsm->a_bus_req = 1;
659 			ci_otg_queue_work(ci);
660 		}
661 		break;
662 	case OTG_STATE_B_IDLE:
663 		if (otg_bsess_vld && (intr_sts & USBi_PCI) && port_conn) {
664 			fsm->b_sess_vld = 1;
665 			ci_otg_queue_work(ci);
666 		}
667 		break;
668 	case OTG_STATE_B_PERIPHERAL:
669 		if ((intr_sts & USBi_SLI) && port_conn && otg_bsess_vld) {
670 			ci_otg_add_timer(ci, B_AIDL_BDIS);
671 		} else if (intr_sts & USBi_PCI) {
672 			ci_otg_del_timer(ci, B_AIDL_BDIS);
673 			if (fsm->a_bus_suspend == 1)
674 				fsm->a_bus_suspend = 0;
675 		}
676 		break;
677 	case OTG_STATE_B_HOST:
678 		if ((intr_sts & USBi_PCI) && !port_conn) {
679 			fsm->a_conn = 0;
680 			fsm->b_bus_req = 0;
681 			ci_otg_queue_work(ci);
682 		}
683 		break;
684 	case OTG_STATE_A_PERIPHERAL:
685 		if (intr_sts & USBi_SLI) {
686 			 fsm->b_bus_suspend = 1;
687 			/*
688 			 * Init a timer to know how long this suspend
689 			 * will continue, if time out, indicates B no longer
690 			 * wants to be host role
691 			 */
692 			 ci_otg_add_timer(ci, A_BIDL_ADIS);
693 		}
694 
695 		if (intr_sts & USBi_URI)
696 			ci_otg_del_timer(ci, A_BIDL_ADIS);
697 
698 		if (intr_sts & USBi_PCI) {
699 			if (fsm->b_bus_suspend == 1) {
700 				ci_otg_del_timer(ci, A_BIDL_ADIS);
701 				fsm->b_bus_suspend = 0;
702 			}
703 		}
704 		break;
705 	case OTG_STATE_A_SUSPEND:
706 		if ((intr_sts & USBi_PCI) && !port_conn) {
707 			fsm->b_conn = 0;
708 
709 			/* if gadget driver is binded */
710 			if (ci->driver) {
711 				/* A device to be peripheral mode */
712 				ci->gadget.is_a_peripheral = 1;
713 			}
714 			ci_otg_queue_work(ci);
715 		}
716 		break;
717 	case OTG_STATE_A_HOST:
718 		if ((intr_sts & USBi_PCI) && !port_conn) {
719 			fsm->b_conn = 0;
720 			ci_otg_queue_work(ci);
721 		}
722 		break;
723 	case OTG_STATE_B_WAIT_ACON:
724 		if ((intr_sts & USBi_PCI) && port_conn) {
725 			fsm->a_conn = 1;
726 			ci_otg_queue_work(ci);
727 		}
728 		break;
729 	default:
730 		break;
731 	}
732 }
733 
734 /*
735  * ci_otg_irq - otg fsm related irq handling
736  * and also update otg fsm variable by monitoring usb host and udc
737  * state change interrupts.
738  * @ci: ci_hdrc
739  */
740 irqreturn_t ci_otg_fsm_irq(struct ci_hdrc *ci)
741 {
742 	irqreturn_t retval =  IRQ_NONE;
743 	u32 otgsc, otg_int_src = 0;
744 	struct otg_fsm *fsm = &ci->fsm;
745 
746 	otgsc = hw_read_otgsc(ci, ~0);
747 	otg_int_src = otgsc & OTGSC_INT_STATUS_BITS & (otgsc >> 8);
748 	fsm->id = (otgsc & OTGSC_ID) ? 1 : 0;
749 
750 	if (otg_int_src) {
751 		if (otg_int_src & OTGSC_DPIS) {
752 			hw_write_otgsc(ci, OTGSC_DPIS, OTGSC_DPIS);
753 			fsm->a_srp_det = 1;
754 			fsm->a_bus_drop = 0;
755 		} else if (otg_int_src & OTGSC_IDIS) {
756 			hw_write_otgsc(ci, OTGSC_IDIS, OTGSC_IDIS);
757 			if (fsm->id == 0) {
758 				fsm->a_bus_drop = 0;
759 				fsm->a_bus_req = 1;
760 				ci->id_event = true;
761 			}
762 		} else if (otg_int_src & OTGSC_BSVIS) {
763 			hw_write_otgsc(ci, OTGSC_BSVIS, OTGSC_BSVIS);
764 			if (otgsc & OTGSC_BSV) {
765 				fsm->b_sess_vld = 1;
766 				ci_otg_del_timer(ci, B_SSEND_SRP);
767 				ci_otg_del_timer(ci, B_SRP_FAIL);
768 				fsm->b_ssend_srp = 0;
769 			} else {
770 				fsm->b_sess_vld = 0;
771 				if (fsm->id)
772 					ci_otg_add_timer(ci, B_SSEND_SRP);
773 			}
774 		} else if (otg_int_src & OTGSC_AVVIS) {
775 			hw_write_otgsc(ci, OTGSC_AVVIS, OTGSC_AVVIS);
776 			if (otgsc & OTGSC_AVV) {
777 				fsm->a_vbus_vld = 1;
778 			} else {
779 				fsm->a_vbus_vld = 0;
780 				fsm->b_conn = 0;
781 			}
782 		}
783 		ci_otg_queue_work(ci);
784 		return IRQ_HANDLED;
785 	}
786 
787 	ci_otg_fsm_event(ci);
788 
789 	return retval;
790 }
791 
792 void ci_hdrc_otg_fsm_start(struct ci_hdrc *ci)
793 {
794 	ci_otg_queue_work(ci);
795 }
796 
797 int ci_hdrc_otg_fsm_init(struct ci_hdrc *ci)
798 {
799 	int retval = 0;
800 
801 	if (ci->phy)
802 		ci->otg.phy = ci->phy;
803 	else
804 		ci->otg.usb_phy = ci->usb_phy;
805 
806 	ci->otg.gadget = &ci->gadget;
807 	ci->fsm.otg = &ci->otg;
808 	ci->fsm.power_up = 1;
809 	ci->fsm.id = hw_read_otgsc(ci, OTGSC_ID) ? 1 : 0;
810 	ci->fsm.otg->state = OTG_STATE_UNDEFINED;
811 	ci->fsm.ops = &ci_otg_ops;
812 	ci->gadget.hnp_polling_support = 1;
813 	ci->fsm.host_req_flag = devm_kzalloc(ci->dev, 1, GFP_KERNEL);
814 	if (!ci->fsm.host_req_flag)
815 		return -ENOMEM;
816 
817 	mutex_init(&ci->fsm.lock);
818 
819 	retval = ci_otg_init_timers(ci);
820 	if (retval) {
821 		dev_err(ci->dev, "Couldn't init OTG timers\n");
822 		return retval;
823 	}
824 	ci->enabled_otg_timer_bits = 0;
825 	ci->next_otg_timer = NUM_OTG_FSM_TIMERS;
826 
827 	retval = sysfs_create_group(&ci->dev->kobj, &inputs_attr_group);
828 	if (retval < 0) {
829 		dev_dbg(ci->dev,
830 			"Can't register sysfs attr group: %d\n", retval);
831 		return retval;
832 	}
833 
834 	/* Enable A vbus valid irq */
835 	hw_write_otgsc(ci, OTGSC_AVVIE, OTGSC_AVVIE);
836 
837 	if (ci->fsm.id) {
838 		ci->fsm.b_ssend_srp =
839 			hw_read_otgsc(ci, OTGSC_BSV) ? 0 : 1;
840 		ci->fsm.b_sess_vld =
841 			hw_read_otgsc(ci, OTGSC_BSV) ? 1 : 0;
842 		/* Enable BSV irq */
843 		hw_write_otgsc(ci, OTGSC_BSVIE, OTGSC_BSVIE);
844 	}
845 
846 	return 0;
847 }
848 
849 void ci_hdrc_otg_fsm_remove(struct ci_hdrc *ci)
850 {
851 	sysfs_remove_group(&ci->dev->kobj, &inputs_attr_group);
852 }
853