1// SPDX-License-Identifier: GPL-2.0
2/*
3 * otg.c - ChipIdea USB IP core OTG driver
4 *
5 * Copyright (C) 2013 Freescale Semiconductor, Inc.
6 *
7 * Author: Peter Chen
8 */
9
10/*
11 * This file mainly handles otgsc register, OTG fsm operations for HNP and SRP
12 * are also included.
13 */
14
15#include <linux/usb/otg.h>
16#include <linux/usb/gadget.h>
17#include <linux/usb/chipidea.h>
18
19#include "ci.h"
20#include "bits.h"
21#include "otg.h"
22#include "otg_fsm.h"
23
24/**
25 * hw_read_otgsc - returns otgsc register bits value.
26 * @ci: the controller
27 * @mask: bitfield mask
28 */
29u32 hw_read_otgsc(struct ci_hdrc *ci, u32 mask)
30{
31	struct ci_hdrc_cable *cable;
32	u32 val = hw_read(ci, OP_OTGSC, mask);
33
34	/*
35	 * If using extcon framework for VBUS and/or ID signal
36	 * detection overwrite OTGSC register value
37	 */
38	cable = &ci->platdata->vbus_extcon;
39	if (!IS_ERR(cable->edev) || ci->role_switch) {
40		if (cable->changed)
41			val |= OTGSC_BSVIS;
42		else
43			val &= ~OTGSC_BSVIS;
44
45		if (cable->connected)
46			val |= OTGSC_BSV;
47		else
48			val &= ~OTGSC_BSV;
49
50		if (cable->enabled)
51			val |= OTGSC_BSVIE;
52		else
53			val &= ~OTGSC_BSVIE;
54	}
55
56	cable = &ci->platdata->id_extcon;
57	if (!IS_ERR(cable->edev) || ci->role_switch) {
58		if (cable->changed)
59			val |= OTGSC_IDIS;
60		else
61			val &= ~OTGSC_IDIS;
62
63		if (cable->connected)
64			val &= ~OTGSC_ID; /* host */
65		else
66			val |= OTGSC_ID; /* device */
67
68		if (cable->enabled)
69			val |= OTGSC_IDIE;
70		else
71			val &= ~OTGSC_IDIE;
72	}
73
74	return val & mask;
75}
76
77/**
78 * hw_write_otgsc - updates target bits of OTGSC register.
79 * @ci: the controller
80 * @mask: bitfield mask
81 * @data: to be written
82 */
83void hw_write_otgsc(struct ci_hdrc *ci, u32 mask, u32 data)
84{
85	struct ci_hdrc_cable *cable;
86
87	cable = &ci->platdata->vbus_extcon;
88	if (!IS_ERR(cable->edev) || ci->role_switch) {
89		if (data & mask & OTGSC_BSVIS)
90			cable->changed = false;
91
92		/* Don't enable vbus interrupt if using external notifier */
93		if (data & mask & OTGSC_BSVIE) {
94			cable->enabled = true;
95			data &= ~OTGSC_BSVIE;
96		} else if (mask & OTGSC_BSVIE) {
97			cable->enabled = false;
98		}
99	}
100
101	cable = &ci->platdata->id_extcon;
102	if (!IS_ERR(cable->edev) || ci->role_switch) {
103		if (data & mask & OTGSC_IDIS)
104			cable->changed = false;
105
106		/* Don't enable id interrupt if using external notifier */
107		if (data & mask & OTGSC_IDIE) {
108			cable->enabled = true;
109			data &= ~OTGSC_IDIE;
110		} else if (mask & OTGSC_IDIE) {
111			cable->enabled = false;
112		}
113	}
114
115	hw_write(ci, OP_OTGSC, mask | OTGSC_INT_STATUS_BITS, data);
116}
117
118/**
119 * ci_otg_role - pick role based on ID pin state
120 * @ci: the controller
121 */
122enum ci_role ci_otg_role(struct ci_hdrc *ci)
123{
124	enum ci_role role = hw_read_otgsc(ci, OTGSC_ID)
125		? CI_ROLE_GADGET
126		: CI_ROLE_HOST;
127
128	return role;
129}
130
131void ci_handle_vbus_change(struct ci_hdrc *ci)
132{
133	if (!ci->is_otg) {
134		if (ci->platdata->flags & CI_HDRC_FORCE_VBUS_ACTIVE_ALWAYS)
135			usb_gadget_vbus_connect(&ci->gadget);
136		return;
137	}
138
139	if (hw_read_otgsc(ci, OTGSC_BSV) && !ci->vbus_active)
140		usb_gadget_vbus_connect(&ci->gadget);
141	else if (!hw_read_otgsc(ci, OTGSC_BSV) && ci->vbus_active)
142		usb_gadget_vbus_disconnect(&ci->gadget);
143}
144
145/**
146 * hw_wait_vbus_lower_bsv - When we switch to device mode, the vbus value
147 *                          should be lower than OTGSC_BSV before connecting
148 *                          to host.
149 *
150 * @ci: the controller
151 *
152 * This function returns an error code if timeout
153 */
154static int hw_wait_vbus_lower_bsv(struct ci_hdrc *ci)
155{
156	unsigned long elapse = jiffies + msecs_to_jiffies(5000);
157	u32 mask = OTGSC_BSV;
158
159	while (hw_read_otgsc(ci, mask)) {
160		if (time_after(jiffies, elapse)) {
161			dev_err(ci->dev, "timeout waiting for %08x in OTGSC\n",
162					mask);
163			return -ETIMEDOUT;
164		}
165		msleep(20);
166	}
167
168	return 0;
169}
170
171void ci_handle_id_switch(struct ci_hdrc *ci)
172{
173	enum ci_role role;
174
175	mutex_lock(&ci->mutex);
176	role = ci_otg_role(ci);
177	if (role != ci->role) {
178		dev_dbg(ci->dev, "switching from %s to %s\n",
179			ci_role(ci)->name, ci->roles[role]->name);
180
181		if (ci->vbus_active && ci->role == CI_ROLE_GADGET)
182			/*
183			 * vbus disconnect event is lost due to role
184			 * switch occurs during system suspend.
185			 */
186			usb_gadget_vbus_disconnect(&ci->gadget);
187
188		ci_role_stop(ci);
189
190		if (role == CI_ROLE_GADGET &&
191				IS_ERR(ci->platdata->vbus_extcon.edev))
192			/*
193			 * Wait vbus lower than OTGSC_BSV before connecting
194			 * to host. If connecting status is from an external
195			 * connector instead of register, we don't need to
196			 * care vbus on the board, since it will not affect
197			 * external connector status.
198			 */
199			hw_wait_vbus_lower_bsv(ci);
200
201		ci_role_start(ci, role);
202		/* vbus change may have already occurred */
203		if (role == CI_ROLE_GADGET)
204			ci_handle_vbus_change(ci);
205	}
206	mutex_unlock(&ci->mutex);
207}
208/**
209 * ci_otg_work - perform otg (vbus/id) event handle
210 * @work: work struct
211 */
212static void ci_otg_work(struct work_struct *work)
213{
214	struct ci_hdrc *ci = container_of(work, struct ci_hdrc, work);
215
216	if (ci_otg_is_fsm_mode(ci) && !ci_otg_fsm_work(ci)) {
217		enable_irq(ci->irq);
218		return;
219	}
220
221	pm_runtime_get_sync(ci->dev);
222
223	if (ci->id_event) {
224		ci->id_event = false;
225		ci_handle_id_switch(ci);
226	}
227
228	if (ci->b_sess_valid_event) {
229		ci->b_sess_valid_event = false;
230		ci_handle_vbus_change(ci);
231	}
232
233	pm_runtime_put_sync(ci->dev);
234
235	enable_irq(ci->irq);
236}
237
238
239/**
240 * ci_hdrc_otg_init - initialize otg struct
241 * @ci: the controller
242 */
243int ci_hdrc_otg_init(struct ci_hdrc *ci)
244{
245	INIT_WORK(&ci->work, ci_otg_work);
246	ci->wq = create_freezable_workqueue("ci_otg");
247	if (!ci->wq) {
248		dev_err(ci->dev, "can't create workqueue\n");
249		return -ENODEV;
250	}
251
252	if (ci_otg_is_fsm_mode(ci))
253		return ci_hdrc_otg_fsm_init(ci);
254
255	return 0;
256}
257
258/**
259 * ci_hdrc_otg_destroy - destroy otg struct
260 * @ci: the controller
261 */
262void ci_hdrc_otg_destroy(struct ci_hdrc *ci)
263{
264	if (ci->wq)
265		destroy_workqueue(ci->wq);
266
267	/* Disable all OTG irq and clear status */
268	hw_write_otgsc(ci, OTGSC_INT_EN_BITS | OTGSC_INT_STATUS_BITS,
269						OTGSC_INT_STATUS_BITS);
270	if (ci_otg_is_fsm_mode(ci))
271		ci_hdrc_otg_fsm_remove(ci);
272}
273