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