summaryrefslogtreecommitdiffstats
path: root/drivers/usb/dwc2/drd.c
blob: 1b39c4776369b476223c9c2a880dc1521867c9a3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
// SPDX-License-Identifier: GPL-2.0
/*
 * drd.c - DesignWare USB2 DRD Controller Dual-role support
 *
 * Copyright (C) 2020 STMicroelectronics
 *
 * Author(s): Amelie Delaunay <amelie.delaunay@st.com>
 */

#include <linux/clk.h>
#include <linux/iopoll.h>
#include <linux/platform_device.h>
#include <linux/usb/role.h>
#include "core.h"

#define dwc2_ovr_gotgctl(gotgctl) \
	((gotgctl) |= GOTGCTL_BVALOEN | GOTGCTL_AVALOEN | GOTGCTL_VBVALOEN | \
	 GOTGCTL_DBNCE_FLTR_BYPASS)

static void dwc2_ovr_init(struct dwc2_hsotg *hsotg)
{
	unsigned long flags;
	u32 gotgctl;

	spin_lock_irqsave(&hsotg->lock, flags);

	gotgctl = dwc2_readl(hsotg, GOTGCTL);
	dwc2_ovr_gotgctl(gotgctl);
	gotgctl &= ~(GOTGCTL_BVALOVAL | GOTGCTL_AVALOVAL | GOTGCTL_VBVALOVAL);
	if (hsotg->role_sw_default_mode == USB_DR_MODE_HOST)
		gotgctl |= GOTGCTL_AVALOVAL | GOTGCTL_VBVALOVAL;
	else if (hsotg->role_sw_default_mode == USB_DR_MODE_PERIPHERAL)
		gotgctl |= GOTGCTL_BVALOVAL | GOTGCTL_VBVALOVAL;
	dwc2_writel(hsotg, gotgctl, GOTGCTL);

	spin_unlock_irqrestore(&hsotg->lock, flags);

	dwc2_force_mode(hsotg, (hsotg->dr_mode == USB_DR_MODE_HOST));
}

static int dwc2_ovr_avalid(struct dwc2_hsotg *hsotg, bool valid)
{
	u32 gotgctl = dwc2_readl(hsotg, GOTGCTL);

	/* Check if A-Session is already in the right state */
	if ((valid && (gotgctl & GOTGCTL_ASESVLD)) ||
	    (!valid && !(gotgctl & GOTGCTL_ASESVLD)))
		return -EALREADY;

	/* Always enable overrides to handle the resume case */
	dwc2_ovr_gotgctl(gotgctl);

	gotgctl &= ~GOTGCTL_BVALOVAL;
	if (valid)
		gotgctl |= GOTGCTL_AVALOVAL | GOTGCTL_VBVALOVAL;
	else
		gotgctl &= ~(GOTGCTL_AVALOVAL | GOTGCTL_VBVALOVAL);
	dwc2_writel(hsotg, gotgctl, GOTGCTL);

	return 0;
}

static int dwc2_ovr_bvalid(struct dwc2_hsotg *hsotg, bool valid)
{
	u32 gotgctl = dwc2_readl(hsotg, GOTGCTL);

	/* Check if B-Session is already in the right state */
	if ((valid && (gotgctl & GOTGCTL_BSESVLD)) ||
	    (!valid && !(gotgctl & GOTGCTL_BSESVLD)))
		return -EALREADY;

	/* Always enable overrides to handle the resume case */
	dwc2_ovr_gotgctl(gotgctl);

	gotgctl &= ~GOTGCTL_AVALOVAL;
	if (valid)
		gotgctl |= GOTGCTL_BVALOVAL | GOTGCTL_VBVALOVAL;
	else
		gotgctl &= ~(GOTGCTL_BVALOVAL | GOTGCTL_VBVALOVAL);
	dwc2_writel(hsotg, gotgctl, GOTGCTL);

	return 0;
}

static int dwc2_drd_role_sw_set(struct usb_role_switch *sw, enum usb_role role)
{
	struct dwc2_hsotg *hsotg = usb_role_switch_get_drvdata(sw);
	unsigned long flags;
	int already = 0;

	/* Skip session not in line with dr_mode */
	if ((role == USB_ROLE_DEVICE && hsotg->dr_mode == USB_DR_MODE_HOST) ||
	    (role == USB_ROLE_HOST && hsotg->dr_mode == USB_DR_MODE_PERIPHERAL))
		return -EINVAL;

#if IS_ENABLED(CONFIG_USB_DWC2_PERIPHERAL) || \
	IS_ENABLED(CONFIG_USB_DWC2_DUAL_ROLE)
	/* Skip session if core is in test mode */
	if (role == USB_ROLE_NONE && hsotg->test_mode) {
		dev_dbg(hsotg->dev, "Core is in test mode\n");
		return -EBUSY;
	}
#endif

	/*
	 * In case of USB_DR_MODE_PERIPHERAL, clock is disabled at the end of
	 * the probe and enabled on udc_start.
	 * If role-switch set is called before the udc_start, we need to enable
	 * the clock to read/write GOTGCTL and GUSBCFG registers to override
	 * mode and sessions. It is the case if cable is plugged at boot.
	 */
	if (!hsotg->ll_hw_enabled && hsotg->clk) {
		int ret = clk_prepare_enable(hsotg->clk);

		if (ret)
			return ret;
	}

	spin_lock_irqsave(&hsotg->lock, flags);

	if (role == USB_ROLE_NONE) {
		/* default operation mode when usb role is USB_ROLE_NONE */
		if (hsotg->role_sw_default_mode == USB_DR_MODE_HOST)
			role = USB_ROLE_HOST;
		else if (hsotg->role_sw_default_mode == USB_DR_MODE_PERIPHERAL)
			role = USB_ROLE_DEVICE;
	}

	if (role == USB_ROLE_HOST) {
		already = dwc2_ovr_avalid(hsotg, true);
	} else if (role == USB_ROLE_DEVICE) {
		already = dwc2_ovr_bvalid(hsotg, true);
		/* This clear DCTL.SFTDISCON bit */
		dwc2_hsotg_core_connect(hsotg);
	} else {
		if (dwc2_is_device_mode(hsotg)) {
			if (!dwc2_ovr_bvalid(hsotg, false))
				/* This set DCTL.SFTDISCON bit */
				dwc2_hsotg_core_disconnect(hsotg);
		} else {
			dwc2_ovr_avalid(hsotg, false);
		}
	}

	spin_unlock_irqrestore(&hsotg->lock, flags);

	if (!already && hsotg->dr_mode == USB_DR_MODE_OTG)
		/* This will raise a Connector ID Status Change Interrupt */
		dwc2_force_mode(hsotg, role == USB_ROLE_HOST);

	if (!hsotg->ll_hw_enabled && hsotg->clk)
		clk_disable_unprepare(hsotg->clk);

	dev_dbg(hsotg->dev, "%s-session valid\n",
		role == USB_ROLE_NONE ? "No" :
		role == USB_ROLE_HOST ? "A" : "B");

	return 0;
}

int dwc2_drd_init(struct dwc2_hsotg *hsotg)
{
	struct usb_role_switch_desc role_sw_desc = {0};
	struct usb_role_switch *role_sw;
	int ret;

	if (!device_property_read_bool(hsotg->dev, "usb-role-switch"))
		return 0;

	hsotg->role_sw_default_mode = usb_get_role_switch_default_mode(hsotg->dev);
	role_sw_desc.driver_data = hsotg;
	role_sw_desc.fwnode = dev_fwnode(hsotg->dev);
	role_sw_desc.set = dwc2_drd_role_sw_set;
	role_sw_desc.allow_userspace_control = true;

	role_sw = usb_role_switch_register(hsotg->dev, &role_sw_desc);
	if (IS_ERR(role_sw)) {
		ret = PTR_ERR(role_sw);
		dev_err(hsotg->dev,
			"failed to register role switch: %d\n", ret);
		return ret;
	}

	hsotg->role_sw = role_sw;

	/* Enable override and initialize values */
	dwc2_ovr_init(hsotg);

	return 0;
}

void dwc2_drd_suspend(struct dwc2_hsotg *hsotg)
{
	u32 gintsts, gintmsk;

	if (hsotg->role_sw && !hsotg->params.external_id_pin_ctl) {
		gintmsk = dwc2_readl(hsotg, GINTMSK);
		gintmsk &= ~GINTSTS_CONIDSTSCHNG;
		dwc2_writel(hsotg, gintmsk, GINTMSK);
		gintsts = dwc2_readl(hsotg, GINTSTS);
		dwc2_writel(hsotg, gintsts | GINTSTS_CONIDSTSCHNG, GINTSTS);
	}
}

void dwc2_drd_resume(struct dwc2_hsotg *hsotg)
{
	u32 gintsts, gintmsk;
	enum usb_role role;

	if (hsotg->role_sw) {
		/* get last known role (as the get ops isn't implemented by this driver) */
		role = usb_role_switch_get_role(hsotg->role_sw);

		if (role == USB_ROLE_NONE) {
			if (hsotg->role_sw_default_mode == USB_DR_MODE_HOST)
				role = USB_ROLE_HOST;
			else if (hsotg->role_sw_default_mode == USB_DR_MODE_PERIPHERAL)
				role = USB_ROLE_DEVICE;
		}

		/* restore last role that may have been lost */
		if (role == USB_ROLE_HOST)
			dwc2_ovr_avalid(hsotg, true);
		else if (role == USB_ROLE_DEVICE)
			dwc2_ovr_bvalid(hsotg, true);

		dwc2_force_mode(hsotg, role == USB_ROLE_HOST);

		dev_dbg(hsotg->dev, "resuming %s-session valid\n",
			role == USB_ROLE_NONE ? "No" :
			role == USB_ROLE_HOST ? "A" : "B");
	}

	if (hsotg->role_sw && !hsotg->params.external_id_pin_ctl) {
		gintsts = dwc2_readl(hsotg, GINTSTS);
		dwc2_writel(hsotg, gintsts | GINTSTS_CONIDSTSCHNG, GINTSTS);
		gintmsk = dwc2_readl(hsotg, GINTMSK);
		gintmsk |= GINTSTS_CONIDSTSCHNG;
		dwc2_writel(hsotg, gintmsk, GINTMSK);
	}
}

void dwc2_drd_exit(struct dwc2_hsotg *hsotg)
{
	if (hsotg->role_sw)
		usb_role_switch_unregister(hsotg->role_sw);
}