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