xref: /openbmc/linux/drivers/usb/chipidea/otg_fsm.c (revision 1edd0337)
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_init(&ci->otg_fsm_hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
428 	ci->otg_fsm_hrtimer.function = ci_otg_hrtimer_func;
429 
430 	return 0;
431 }
432 
433 /* -------------------------------------------------------------*/
434 /* Operations that will be called from OTG Finite State Machine */
435 /* -------------------------------------------------------------*/
436 static void ci_otg_fsm_add_timer(struct otg_fsm *fsm, enum otg_fsm_timer t)
437 {
438 	struct ci_hdrc	*ci = container_of(fsm, struct ci_hdrc, fsm);
439 
440 	if (t < NUM_OTG_FSM_TIMERS)
441 		ci_otg_add_timer(ci, t);
442 	return;
443 }
444 
445 static void ci_otg_fsm_del_timer(struct otg_fsm *fsm, enum otg_fsm_timer t)
446 {
447 	struct ci_hdrc	*ci = container_of(fsm, struct ci_hdrc, fsm);
448 
449 	if (t < NUM_OTG_FSM_TIMERS)
450 		ci_otg_del_timer(ci, t);
451 	return;
452 }
453 
454 /*
455  * A-device drive vbus: turn on vbus regulator and enable port power
456  * Data pulse irq should be disabled while vbus is on.
457  */
458 static void ci_otg_drv_vbus(struct otg_fsm *fsm, int on)
459 {
460 	int ret;
461 	struct ci_hdrc	*ci = container_of(fsm, struct ci_hdrc, fsm);
462 
463 	if (on) {
464 		/* Enable power */
465 		hw_write(ci, OP_PORTSC, PORTSC_W1C_BITS | PORTSC_PP,
466 							PORTSC_PP);
467 		if (ci->platdata->reg_vbus) {
468 			ret = regulator_enable(ci->platdata->reg_vbus);
469 			if (ret) {
470 				dev_err(ci->dev,
471 				"Failed to enable vbus regulator, ret=%d\n",
472 				ret);
473 				return;
474 			}
475 		}
476 
477 		if (ci->platdata->flags & CI_HDRC_PHY_VBUS_CONTROL)
478 			usb_phy_vbus_on(ci->usb_phy);
479 
480 		/* Disable data pulse irq */
481 		hw_write_otgsc(ci, OTGSC_DPIE, 0);
482 
483 		fsm->a_srp_det = 0;
484 		fsm->power_up = 0;
485 	} else {
486 		if (ci->platdata->reg_vbus)
487 			regulator_disable(ci->platdata->reg_vbus);
488 
489 		if (ci->platdata->flags & CI_HDRC_PHY_VBUS_CONTROL)
490 			usb_phy_vbus_off(ci->usb_phy);
491 
492 		fsm->a_bus_drop = 1;
493 		fsm->a_bus_req = 0;
494 	}
495 }
496 
497 /*
498  * Control data line by Run Stop bit.
499  */
500 static void ci_otg_loc_conn(struct otg_fsm *fsm, int on)
501 {
502 	struct ci_hdrc	*ci = container_of(fsm, struct ci_hdrc, fsm);
503 
504 	if (on)
505 		hw_write(ci, OP_USBCMD, USBCMD_RS, USBCMD_RS);
506 	else
507 		hw_write(ci, OP_USBCMD, USBCMD_RS, 0);
508 }
509 
510 /*
511  * Generate SOF by host.
512  * In host mode, controller will automatically send SOF.
513  * Suspend will block the data on the port.
514  *
515  * This is controlled through usbcore by usb autosuspend,
516  * so the usb device class driver need support autosuspend,
517  * otherwise the bus suspend will not happen.
518  */
519 static void ci_otg_loc_sof(struct otg_fsm *fsm, int on)
520 {
521 	struct usb_device *udev;
522 
523 	if (!fsm->otg->host)
524 		return;
525 
526 	udev = usb_hub_find_child(fsm->otg->host->root_hub, 1);
527 	if (!udev)
528 		return;
529 
530 	if (on) {
531 		usb_disable_autosuspend(udev);
532 	} else {
533 		pm_runtime_set_autosuspend_delay(&udev->dev, 0);
534 		usb_enable_autosuspend(udev);
535 	}
536 }
537 
538 /*
539  * Start SRP pulsing by data-line pulsing,
540  * no v-bus pulsing followed
541  */
542 static void ci_otg_start_pulse(struct otg_fsm *fsm)
543 {
544 	struct ci_hdrc	*ci = container_of(fsm, struct ci_hdrc, fsm);
545 
546 	/* Hardware Assistant Data pulse */
547 	hw_write_otgsc(ci, OTGSC_HADP, OTGSC_HADP);
548 
549 	pm_runtime_get(ci->dev);
550 	ci_otg_add_timer(ci, B_DATA_PLS);
551 }
552 
553 static int ci_otg_start_host(struct otg_fsm *fsm, int on)
554 {
555 	struct ci_hdrc	*ci = container_of(fsm, struct ci_hdrc, fsm);
556 
557 	if (on) {
558 		ci_role_stop(ci);
559 		ci_role_start(ci, CI_ROLE_HOST);
560 	} else {
561 		ci_role_stop(ci);
562 		ci_role_start(ci, CI_ROLE_GADGET);
563 	}
564 	return 0;
565 }
566 
567 static int ci_otg_start_gadget(struct otg_fsm *fsm, int on)
568 {
569 	struct ci_hdrc	*ci = container_of(fsm, struct ci_hdrc, fsm);
570 
571 	if (on)
572 		usb_gadget_vbus_connect(&ci->gadget);
573 	else
574 		usb_gadget_vbus_disconnect(&ci->gadget);
575 
576 	return 0;
577 }
578 
579 static struct otg_fsm_ops ci_otg_ops = {
580 	.drv_vbus = ci_otg_drv_vbus,
581 	.loc_conn = ci_otg_loc_conn,
582 	.loc_sof = ci_otg_loc_sof,
583 	.start_pulse = ci_otg_start_pulse,
584 	.add_timer = ci_otg_fsm_add_timer,
585 	.del_timer = ci_otg_fsm_del_timer,
586 	.start_host = ci_otg_start_host,
587 	.start_gadget = ci_otg_start_gadget,
588 };
589 
590 int ci_otg_fsm_work(struct ci_hdrc *ci)
591 {
592 	/*
593 	 * Don't do fsm transition for B device
594 	 * when there is no gadget class driver
595 	 */
596 	if (ci->fsm.id && !(ci->driver) &&
597 		ci->fsm.otg->state < OTG_STATE_A_IDLE)
598 		return 0;
599 
600 	pm_runtime_get_sync(ci->dev);
601 	if (otg_statemachine(&ci->fsm)) {
602 		if (ci->fsm.otg->state == OTG_STATE_A_IDLE) {
603 			/*
604 			 * Further state change for cases:
605 			 * a_idle to b_idle; or
606 			 * a_idle to a_wait_vrise due to ID change(1->0), so
607 			 * B-dev becomes A-dev can try to start new session
608 			 * consequently; or
609 			 * a_idle to a_wait_vrise when power up
610 			 */
611 			if ((ci->fsm.id) || (ci->id_event) ||
612 						(ci->fsm.power_up)) {
613 				ci_otg_queue_work(ci);
614 			} else {
615 				/* Enable data pulse irq */
616 				hw_write(ci, OP_PORTSC, PORTSC_W1C_BITS |
617 								PORTSC_PP, 0);
618 				hw_write_otgsc(ci, OTGSC_DPIS, OTGSC_DPIS);
619 				hw_write_otgsc(ci, OTGSC_DPIE, OTGSC_DPIE);
620 			}
621 			if (ci->id_event)
622 				ci->id_event = false;
623 		} else if (ci->fsm.otg->state == OTG_STATE_B_IDLE) {
624 			if (ci->fsm.b_sess_vld) {
625 				ci->fsm.power_up = 0;
626 				/*
627 				 * Further transite to b_periphearl state
628 				 * when register gadget driver with vbus on
629 				 */
630 				ci_otg_queue_work(ci);
631 			}
632 		} else if (ci->fsm.otg->state == OTG_STATE_A_HOST) {
633 			pm_runtime_mark_last_busy(ci->dev);
634 			pm_runtime_put_autosuspend(ci->dev);
635 			return 0;
636 		}
637 	}
638 	pm_runtime_put_sync(ci->dev);
639 	return 0;
640 }
641 
642 /*
643  * Update fsm variables in each state if catching expected interrupts,
644  * called by otg fsm isr.
645  */
646 static void ci_otg_fsm_event(struct ci_hdrc *ci)
647 {
648 	u32 intr_sts, otg_bsess_vld, port_conn;
649 	struct otg_fsm *fsm = &ci->fsm;
650 
651 	intr_sts = hw_read_intr_status(ci);
652 	otg_bsess_vld = hw_read_otgsc(ci, OTGSC_BSV);
653 	port_conn = hw_read(ci, OP_PORTSC, PORTSC_CCS);
654 
655 	switch (ci->fsm.otg->state) {
656 	case OTG_STATE_A_WAIT_BCON:
657 		if (port_conn) {
658 			fsm->b_conn = 1;
659 			fsm->a_bus_req = 1;
660 			ci_otg_queue_work(ci);
661 		}
662 		break;
663 	case OTG_STATE_B_IDLE:
664 		if (otg_bsess_vld && (intr_sts & USBi_PCI) && port_conn) {
665 			fsm->b_sess_vld = 1;
666 			ci_otg_queue_work(ci);
667 		}
668 		break;
669 	case OTG_STATE_B_PERIPHERAL:
670 		if ((intr_sts & USBi_SLI) && port_conn && otg_bsess_vld) {
671 			ci_otg_add_timer(ci, B_AIDL_BDIS);
672 		} else if (intr_sts & USBi_PCI) {
673 			ci_otg_del_timer(ci, B_AIDL_BDIS);
674 			if (fsm->a_bus_suspend == 1)
675 				fsm->a_bus_suspend = 0;
676 		}
677 		break;
678 	case OTG_STATE_B_HOST:
679 		if ((intr_sts & USBi_PCI) && !port_conn) {
680 			fsm->a_conn = 0;
681 			fsm->b_bus_req = 0;
682 			ci_otg_queue_work(ci);
683 		}
684 		break;
685 	case OTG_STATE_A_PERIPHERAL:
686 		if (intr_sts & USBi_SLI) {
687 			 fsm->b_bus_suspend = 1;
688 			/*
689 			 * Init a timer to know how long this suspend
690 			 * will continue, if time out, indicates B no longer
691 			 * wants to be host role
692 			 */
693 			 ci_otg_add_timer(ci, A_BIDL_ADIS);
694 		}
695 
696 		if (intr_sts & USBi_URI)
697 			ci_otg_del_timer(ci, A_BIDL_ADIS);
698 
699 		if (intr_sts & USBi_PCI) {
700 			if (fsm->b_bus_suspend == 1) {
701 				ci_otg_del_timer(ci, A_BIDL_ADIS);
702 				fsm->b_bus_suspend = 0;
703 			}
704 		}
705 		break;
706 	case OTG_STATE_A_SUSPEND:
707 		if ((intr_sts & USBi_PCI) && !port_conn) {
708 			fsm->b_conn = 0;
709 
710 			/* if gadget driver is binded */
711 			if (ci->driver) {
712 				/* A device to be peripheral mode */
713 				ci->gadget.is_a_peripheral = 1;
714 			}
715 			ci_otg_queue_work(ci);
716 		}
717 		break;
718 	case OTG_STATE_A_HOST:
719 		if ((intr_sts & USBi_PCI) && !port_conn) {
720 			fsm->b_conn = 0;
721 			ci_otg_queue_work(ci);
722 		}
723 		break;
724 	case OTG_STATE_B_WAIT_ACON:
725 		if ((intr_sts & USBi_PCI) && port_conn) {
726 			fsm->a_conn = 1;
727 			ci_otg_queue_work(ci);
728 		}
729 		break;
730 	default:
731 		break;
732 	}
733 }
734 
735 /*
736  * ci_otg_irq - otg fsm related irq handling
737  * and also update otg fsm variable by monitoring usb host and udc
738  * state change interrupts.
739  * @ci: ci_hdrc
740  */
741 irqreturn_t ci_otg_fsm_irq(struct ci_hdrc *ci)
742 {
743 	irqreturn_t retval =  IRQ_NONE;
744 	u32 otgsc, otg_int_src = 0;
745 	struct otg_fsm *fsm = &ci->fsm;
746 
747 	otgsc = hw_read_otgsc(ci, ~0);
748 	otg_int_src = otgsc & OTGSC_INT_STATUS_BITS & (otgsc >> 8);
749 	fsm->id = (otgsc & OTGSC_ID) ? 1 : 0;
750 
751 	if (otg_int_src) {
752 		if (otg_int_src & OTGSC_DPIS) {
753 			hw_write_otgsc(ci, OTGSC_DPIS, OTGSC_DPIS);
754 			fsm->a_srp_det = 1;
755 			fsm->a_bus_drop = 0;
756 		} else if (otg_int_src & OTGSC_IDIS) {
757 			hw_write_otgsc(ci, OTGSC_IDIS, OTGSC_IDIS);
758 			if (fsm->id == 0) {
759 				fsm->a_bus_drop = 0;
760 				fsm->a_bus_req = 1;
761 				ci->id_event = true;
762 			}
763 		} else if (otg_int_src & OTGSC_BSVIS) {
764 			hw_write_otgsc(ci, OTGSC_BSVIS, OTGSC_BSVIS);
765 			if (otgsc & OTGSC_BSV) {
766 				fsm->b_sess_vld = 1;
767 				ci_otg_del_timer(ci, B_SSEND_SRP);
768 				ci_otg_del_timer(ci, B_SRP_FAIL);
769 				fsm->b_ssend_srp = 0;
770 			} else {
771 				fsm->b_sess_vld = 0;
772 				if (fsm->id)
773 					ci_otg_add_timer(ci, B_SSEND_SRP);
774 			}
775 		} else if (otg_int_src & OTGSC_AVVIS) {
776 			hw_write_otgsc(ci, OTGSC_AVVIS, OTGSC_AVVIS);
777 			if (otgsc & OTGSC_AVV) {
778 				fsm->a_vbus_vld = 1;
779 			} else {
780 				fsm->a_vbus_vld = 0;
781 				fsm->b_conn = 0;
782 			}
783 		}
784 		ci_otg_queue_work(ci);
785 		return IRQ_HANDLED;
786 	}
787 
788 	ci_otg_fsm_event(ci);
789 
790 	return retval;
791 }
792 
793 void ci_hdrc_otg_fsm_start(struct ci_hdrc *ci)
794 {
795 	ci_otg_queue_work(ci);
796 }
797 
798 int ci_hdrc_otg_fsm_init(struct ci_hdrc *ci)
799 {
800 	int retval = 0;
801 
802 	if (ci->phy)
803 		ci->otg.phy = ci->phy;
804 	else
805 		ci->otg.usb_phy = ci->usb_phy;
806 
807 	ci->otg.gadget = &ci->gadget;
808 	ci->fsm.otg = &ci->otg;
809 	ci->fsm.power_up = 1;
810 	ci->fsm.id = hw_read_otgsc(ci, OTGSC_ID) ? 1 : 0;
811 	ci->fsm.otg->state = OTG_STATE_UNDEFINED;
812 	ci->fsm.ops = &ci_otg_ops;
813 	ci->gadget.hnp_polling_support = 1;
814 	ci->fsm.host_req_flag = devm_kzalloc(ci->dev, 1, GFP_KERNEL);
815 	if (!ci->fsm.host_req_flag)
816 		return -ENOMEM;
817 
818 	mutex_init(&ci->fsm.lock);
819 
820 	retval = ci_otg_init_timers(ci);
821 	if (retval) {
822 		dev_err(ci->dev, "Couldn't init OTG timers\n");
823 		return retval;
824 	}
825 	ci->enabled_otg_timer_bits = 0;
826 	ci->next_otg_timer = NUM_OTG_FSM_TIMERS;
827 
828 	retval = sysfs_create_group(&ci->dev->kobj, &inputs_attr_group);
829 	if (retval < 0) {
830 		dev_dbg(ci->dev,
831 			"Can't register sysfs attr group: %d\n", retval);
832 		return retval;
833 	}
834 
835 	/* Enable A vbus valid irq */
836 	hw_write_otgsc(ci, OTGSC_AVVIE, OTGSC_AVVIE);
837 
838 	if (ci->fsm.id) {
839 		ci->fsm.b_ssend_srp =
840 			hw_read_otgsc(ci, OTGSC_BSV) ? 0 : 1;
841 		ci->fsm.b_sess_vld =
842 			hw_read_otgsc(ci, OTGSC_BSV) ? 1 : 0;
843 		/* Enable BSV irq */
844 		hw_write_otgsc(ci, OTGSC_BSVIE, OTGSC_BSVIE);
845 	}
846 
847 	return 0;
848 }
849 
850 void ci_hdrc_otg_fsm_remove(struct ci_hdrc *ci)
851 {
852 	sysfs_remove_group(&ci->dev->kobj, &inputs_attr_group);
853 }
854