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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * drd.c - DesignWare USB2 DRD Controller Dual-role support
4 *
5 * Copyright (C) 2020 STMicroelectronics
6 *
7 * Author(s): Amelie Delaunay <amelie.delaunay@st.com>
8 */
9
10#include <linux/clk.h>
11#include <linux/iopoll.h>
12#include <linux/platform_device.h>
13#include <linux/usb/role.h>
14#include "core.h"
15
16#define dwc2_ovr_gotgctl(gotgctl) \
17 ((gotgctl) |= GOTGCTL_BVALOEN | GOTGCTL_AVALOEN | GOTGCTL_VBVALOEN | \
18 GOTGCTL_DBNCE_FLTR_BYPASS)
19
20static void dwc2_ovr_init(struct dwc2_hsotg *hsotg)
21{
22 unsigned long flags;
23 u32 gotgctl;
24
25 spin_lock_irqsave(&hsotg->lock, flags);
26
27 gotgctl = dwc2_readl(hsotg, GOTGCTL);
28 dwc2_ovr_gotgctl(gotgctl);
29 gotgctl &= ~(GOTGCTL_BVALOVAL | GOTGCTL_AVALOVAL | GOTGCTL_VBVALOVAL);
30 if (hsotg->role_sw_default_mode == USB_DR_MODE_HOST)
31 gotgctl |= GOTGCTL_AVALOVAL | GOTGCTL_VBVALOVAL;
32 else if (hsotg->role_sw_default_mode == USB_DR_MODE_PERIPHERAL)
33 gotgctl |= GOTGCTL_BVALOVAL | GOTGCTL_VBVALOVAL;
34 dwc2_writel(hsotg, gotgctl, GOTGCTL);
35
36 spin_unlock_irqrestore(&hsotg->lock, flags);
37
38 dwc2_force_mode(hsotg, (hsotg->dr_mode == USB_DR_MODE_HOST) ||
39 (hsotg->role_sw_default_mode == USB_DR_MODE_HOST));
40}
41
42static int dwc2_ovr_avalid(struct dwc2_hsotg *hsotg, bool valid)
43{
44 u32 gotgctl = dwc2_readl(hsotg, GOTGCTL);
45
46 /* Check if A-Session is already in the right state */
47 if ((valid && (gotgctl & GOTGCTL_ASESVLD)) ||
48 (!valid && !(gotgctl & GOTGCTL_ASESVLD)))
49 return -EALREADY;
50
51 /* Always enable overrides to handle the resume case */
52 dwc2_ovr_gotgctl(gotgctl);
53
54 gotgctl &= ~GOTGCTL_BVALOVAL;
55 if (valid)
56 gotgctl |= GOTGCTL_AVALOVAL | GOTGCTL_VBVALOVAL;
57 else
58 gotgctl &= ~(GOTGCTL_AVALOVAL | GOTGCTL_VBVALOVAL);
59 dwc2_writel(hsotg, gotgctl, GOTGCTL);
60
61 return 0;
62}
63
64static int dwc2_ovr_bvalid(struct dwc2_hsotg *hsotg, bool valid)
65{
66 u32 gotgctl = dwc2_readl(hsotg, GOTGCTL);
67
68 /* Check if B-Session is already in the right state */
69 if ((valid && (gotgctl & GOTGCTL_BSESVLD)) ||
70 (!valid && !(gotgctl & GOTGCTL_BSESVLD)))
71 return -EALREADY;
72
73 /* Always enable overrides to handle the resume case */
74 dwc2_ovr_gotgctl(gotgctl);
75
76 gotgctl &= ~GOTGCTL_AVALOVAL;
77 if (valid)
78 gotgctl |= GOTGCTL_BVALOVAL | GOTGCTL_VBVALOVAL;
79 else
80 gotgctl &= ~(GOTGCTL_BVALOVAL | GOTGCTL_VBVALOVAL);
81 dwc2_writel(hsotg, gotgctl, GOTGCTL);
82
83 return 0;
84}
85
86static int dwc2_drd_role_sw_set(struct usb_role_switch *sw, enum usb_role role)
87{
88 struct dwc2_hsotg *hsotg = usb_role_switch_get_drvdata(sw);
89 unsigned long flags;
90 int already = 0;
91
92 /* Skip session not in line with dr_mode */
93 if ((role == USB_ROLE_DEVICE && hsotg->dr_mode == USB_DR_MODE_HOST) ||
94 (role == USB_ROLE_HOST && hsotg->dr_mode == USB_DR_MODE_PERIPHERAL))
95 return -EINVAL;
96
97#if IS_ENABLED(CONFIG_USB_DWC2_PERIPHERAL) || \
98 IS_ENABLED(CONFIG_USB_DWC2_DUAL_ROLE)
99 /* Skip session if core is in test mode */
100 if (role == USB_ROLE_NONE && hsotg->test_mode) {
101 dev_dbg(hsotg->dev, "Core is in test mode\n");
102 return -EBUSY;
103 }
104#endif
105
106 /*
107 * In case of USB_DR_MODE_PERIPHERAL, clock is disabled at the end of
108 * the probe and enabled on udc_start.
109 * If role-switch set is called before the udc_start, we need to enable
110 * the clock to read/write GOTGCTL and GUSBCFG registers to override
111 * mode and sessions. It is the case if cable is plugged at boot.
112 */
113 if (!hsotg->ll_hw_enabled && hsotg->clk) {
114 int ret = clk_prepare_enable(hsotg->clk);
115
116 if (ret)
117 return ret;
118 }
119
120 spin_lock_irqsave(&hsotg->lock, flags);
121
122 if (role == USB_ROLE_NONE) {
123 /* default operation mode when usb role is USB_ROLE_NONE */
124 if (hsotg->role_sw_default_mode == USB_DR_MODE_HOST)
125 role = USB_ROLE_HOST;
126 else if (hsotg->role_sw_default_mode == USB_DR_MODE_PERIPHERAL)
127 role = USB_ROLE_DEVICE;
128 }
129
130 if (role == USB_ROLE_HOST) {
131 already = dwc2_ovr_avalid(hsotg, true);
132 } else if (role == USB_ROLE_DEVICE) {
133 already = dwc2_ovr_bvalid(hsotg, true);
134 if (dwc2_is_device_enabled(hsotg)) {
135 /* This clear DCTL.SFTDISCON bit */
136 dwc2_hsotg_core_connect(hsotg);
137 }
138 } else {
139 if (dwc2_is_device_mode(hsotg)) {
140 if (!dwc2_ovr_bvalid(hsotg, false))
141 /* This set DCTL.SFTDISCON bit */
142 dwc2_hsotg_core_disconnect(hsotg);
143 } else {
144 dwc2_ovr_avalid(hsotg, false);
145 }
146 }
147
148 spin_unlock_irqrestore(&hsotg->lock, flags);
149
150 if (!already && hsotg->dr_mode == USB_DR_MODE_OTG)
151 /* This will raise a Connector ID Status Change Interrupt */
152 dwc2_force_mode(hsotg, role == USB_ROLE_HOST);
153
154 if (!hsotg->ll_hw_enabled && hsotg->clk)
155 clk_disable_unprepare(hsotg->clk);
156
157 dev_dbg(hsotg->dev, "%s-session valid\n",
158 role == USB_ROLE_NONE ? "No" :
159 role == USB_ROLE_HOST ? "A" : "B");
160
161 return 0;
162}
163
164int dwc2_drd_init(struct dwc2_hsotg *hsotg)
165{
166 struct usb_role_switch_desc role_sw_desc = {0};
167 struct usb_role_switch *role_sw;
168 int ret;
169
170 if (!device_property_read_bool(hsotg->dev, "usb-role-switch"))
171 return 0;
172
173 hsotg->role_sw_default_mode = usb_get_role_switch_default_mode(hsotg->dev);
174 role_sw_desc.driver_data = hsotg;
175 role_sw_desc.fwnode = dev_fwnode(hsotg->dev);
176 role_sw_desc.set = dwc2_drd_role_sw_set;
177 role_sw_desc.allow_userspace_control = true;
178
179 role_sw = usb_role_switch_register(hsotg->dev, &role_sw_desc);
180 if (IS_ERR(role_sw)) {
181 ret = PTR_ERR(role_sw);
182 dev_err(hsotg->dev,
183 "failed to register role switch: %d\n", ret);
184 return ret;
185 }
186
187 hsotg->role_sw = role_sw;
188
189 /* Enable override and initialize values */
190 dwc2_ovr_init(hsotg);
191
192 return 0;
193}
194
195void dwc2_drd_suspend(struct dwc2_hsotg *hsotg)
196{
197 u32 gintsts, gintmsk;
198
199 if (hsotg->role_sw && !hsotg->params.external_id_pin_ctl) {
200 gintmsk = dwc2_readl(hsotg, GINTMSK);
201 gintmsk &= ~GINTSTS_CONIDSTSCHNG;
202 dwc2_writel(hsotg, gintmsk, GINTMSK);
203 gintsts = dwc2_readl(hsotg, GINTSTS);
204 dwc2_writel(hsotg, gintsts | GINTSTS_CONIDSTSCHNG, GINTSTS);
205 }
206}
207
208void dwc2_drd_resume(struct dwc2_hsotg *hsotg)
209{
210 u32 gintsts, gintmsk;
211 enum usb_role role;
212
213 if (hsotg->role_sw) {
214 /* get last known role (as the get ops isn't implemented by this driver) */
215 role = usb_role_switch_get_role(hsotg->role_sw);
216
217 if (role == USB_ROLE_NONE) {
218 if (hsotg->role_sw_default_mode == USB_DR_MODE_HOST)
219 role = USB_ROLE_HOST;
220 else if (hsotg->role_sw_default_mode == USB_DR_MODE_PERIPHERAL)
221 role = USB_ROLE_DEVICE;
222 }
223
224 /* restore last role that may have been lost */
225 if (role == USB_ROLE_HOST)
226 dwc2_ovr_avalid(hsotg, true);
227 else if (role == USB_ROLE_DEVICE)
228 dwc2_ovr_bvalid(hsotg, true);
229
230 dwc2_force_mode(hsotg, role == USB_ROLE_HOST);
231
232 dev_dbg(hsotg->dev, "resuming %s-session valid\n",
233 role == USB_ROLE_NONE ? "No" :
234 role == USB_ROLE_HOST ? "A" : "B");
235 }
236
237 if (hsotg->role_sw && !hsotg->params.external_id_pin_ctl) {
238 gintsts = dwc2_readl(hsotg, GINTSTS);
239 dwc2_writel(hsotg, gintsts | GINTSTS_CONIDSTSCHNG, GINTSTS);
240 gintmsk = dwc2_readl(hsotg, GINTMSK);
241 gintmsk |= GINTSTS_CONIDSTSCHNG;
242 dwc2_writel(hsotg, gintmsk, GINTMSK);
243 }
244}
245
246void dwc2_drd_exit(struct dwc2_hsotg *hsotg)
247{
248 if (hsotg->role_sw)
249 usb_role_switch_unregister(hsotg->role_sw);
250}