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
dwc2_ovr_init(struct dwc2_hsotg * hsotg)16 static void dwc2_ovr_init(struct dwc2_hsotg *hsotg)
17 {
18 unsigned long flags;
19 u32 gotgctl;
20
21 spin_lock_irqsave(&hsotg->lock, flags);
22
23 gotgctl = dwc2_readl(hsotg, GOTGCTL);
24 gotgctl |= GOTGCTL_BVALOEN | GOTGCTL_AVALOEN | GOTGCTL_VBVALOEN;
25 gotgctl |= GOTGCTL_DBNCE_FLTR_BYPASS;
26 gotgctl &= ~(GOTGCTL_BVALOVAL | GOTGCTL_AVALOVAL | GOTGCTL_VBVALOVAL);
27 dwc2_writel(hsotg, gotgctl, GOTGCTL);
28
29 spin_unlock_irqrestore(&hsotg->lock, flags);
30
31 dwc2_force_mode(hsotg, (hsotg->dr_mode == USB_DR_MODE_HOST));
32 }
33
dwc2_ovr_avalid(struct dwc2_hsotg * hsotg,bool valid)34 static int dwc2_ovr_avalid(struct dwc2_hsotg *hsotg, bool valid)
35 {
36 u32 gotgctl = dwc2_readl(hsotg, GOTGCTL);
37
38 /* Check if A-Session is already in the right state */
39 if ((valid && (gotgctl & GOTGCTL_ASESVLD)) ||
40 (!valid && !(gotgctl & GOTGCTL_ASESVLD)))
41 return -EALREADY;
42
43 gotgctl &= ~GOTGCTL_BVALOVAL;
44 if (valid)
45 gotgctl |= GOTGCTL_AVALOVAL | GOTGCTL_VBVALOVAL;
46 else
47 gotgctl &= ~(GOTGCTL_AVALOVAL | GOTGCTL_VBVALOVAL);
48 dwc2_writel(hsotg, gotgctl, GOTGCTL);
49
50 return 0;
51 }
52
dwc2_ovr_bvalid(struct dwc2_hsotg * hsotg,bool valid)53 static int dwc2_ovr_bvalid(struct dwc2_hsotg *hsotg, bool valid)
54 {
55 u32 gotgctl = dwc2_readl(hsotg, GOTGCTL);
56
57 /* Check if B-Session is already in the right state */
58 if ((valid && (gotgctl & GOTGCTL_BSESVLD)) ||
59 (!valid && !(gotgctl & GOTGCTL_BSESVLD)))
60 return -EALREADY;
61
62 gotgctl &= ~GOTGCTL_AVALOVAL;
63 if (valid)
64 gotgctl |= GOTGCTL_BVALOVAL | GOTGCTL_VBVALOVAL;
65 else
66 gotgctl &= ~(GOTGCTL_BVALOVAL | GOTGCTL_VBVALOVAL);
67 dwc2_writel(hsotg, gotgctl, GOTGCTL);
68
69 return 0;
70 }
71
dwc2_drd_role_sw_set(struct usb_role_switch * sw,enum usb_role role)72 static int dwc2_drd_role_sw_set(struct usb_role_switch *sw, enum usb_role role)
73 {
74 struct dwc2_hsotg *hsotg = usb_role_switch_get_drvdata(sw);
75 unsigned long flags;
76 int already = 0;
77
78 /* Skip session not in line with dr_mode */
79 if ((role == USB_ROLE_DEVICE && hsotg->dr_mode == USB_DR_MODE_HOST) ||
80 (role == USB_ROLE_HOST && hsotg->dr_mode == USB_DR_MODE_PERIPHERAL))
81 return -EINVAL;
82
83 #if IS_ENABLED(CONFIG_USB_DWC2_PERIPHERAL) || \
84 IS_ENABLED(CONFIG_USB_DWC2_DUAL_ROLE)
85 /* Skip session if core is in test mode */
86 if (role == USB_ROLE_NONE && hsotg->test_mode) {
87 dev_dbg(hsotg->dev, "Core is in test mode\n");
88 return -EBUSY;
89 }
90 #endif
91
92 /*
93 * In case of USB_DR_MODE_PERIPHERAL, clock is disabled at the end of
94 * the probe and enabled on udc_start.
95 * If role-switch set is called before the udc_start, we need to enable
96 * the clock to read/write GOTGCTL and GUSBCFG registers to override
97 * mode and sessions. It is the case if cable is plugged at boot.
98 */
99 if (!hsotg->ll_hw_enabled && hsotg->clk) {
100 int ret = clk_prepare_enable(hsotg->clk);
101
102 if (ret)
103 return ret;
104 }
105
106 spin_lock_irqsave(&hsotg->lock, flags);
107
108 if (role == USB_ROLE_HOST) {
109 already = dwc2_ovr_avalid(hsotg, true);
110 } else if (role == USB_ROLE_DEVICE) {
111 already = dwc2_ovr_bvalid(hsotg, true);
112 if (dwc2_is_device_enabled(hsotg)) {
113 /* This clear DCTL.SFTDISCON bit */
114 dwc2_hsotg_core_connect(hsotg);
115 }
116 } else {
117 if (dwc2_is_device_mode(hsotg)) {
118 if (!dwc2_ovr_bvalid(hsotg, false))
119 /* This set DCTL.SFTDISCON bit */
120 dwc2_hsotg_core_disconnect(hsotg);
121 } else {
122 dwc2_ovr_avalid(hsotg, false);
123 }
124 }
125
126 spin_unlock_irqrestore(&hsotg->lock, flags);
127
128 if (!already && hsotg->dr_mode == USB_DR_MODE_OTG)
129 /* This will raise a Connector ID Status Change Interrupt */
130 dwc2_force_mode(hsotg, role == USB_ROLE_HOST);
131
132 if (!hsotg->ll_hw_enabled && hsotg->clk)
133 clk_disable_unprepare(hsotg->clk);
134
135 dev_dbg(hsotg->dev, "%s-session valid\n",
136 role == USB_ROLE_NONE ? "No" :
137 role == USB_ROLE_HOST ? "A" : "B");
138
139 return 0;
140 }
141
dwc2_drd_init(struct dwc2_hsotg * hsotg)142 int dwc2_drd_init(struct dwc2_hsotg *hsotg)
143 {
144 struct usb_role_switch_desc role_sw_desc = {0};
145 struct usb_role_switch *role_sw;
146 int ret;
147
148 if (!device_property_read_bool(hsotg->dev, "usb-role-switch"))
149 return 0;
150
151 role_sw_desc.driver_data = hsotg;
152 role_sw_desc.fwnode = dev_fwnode(hsotg->dev);
153 role_sw_desc.set = dwc2_drd_role_sw_set;
154 role_sw_desc.allow_userspace_control = true;
155
156 role_sw = usb_role_switch_register(hsotg->dev, &role_sw_desc);
157 if (IS_ERR(role_sw)) {
158 ret = PTR_ERR(role_sw);
159 dev_err(hsotg->dev,
160 "failed to register role switch: %d\n", ret);
161 return ret;
162 }
163
164 hsotg->role_sw = role_sw;
165
166 /* Enable override and initialize values */
167 dwc2_ovr_init(hsotg);
168
169 return 0;
170 }
171
dwc2_drd_suspend(struct dwc2_hsotg * hsotg)172 void dwc2_drd_suspend(struct dwc2_hsotg *hsotg)
173 {
174 u32 gintsts, gintmsk;
175
176 if (hsotg->role_sw && !hsotg->params.external_id_pin_ctl) {
177 gintmsk = dwc2_readl(hsotg, GINTMSK);
178 gintmsk &= ~GINTSTS_CONIDSTSCHNG;
179 dwc2_writel(hsotg, gintmsk, GINTMSK);
180 gintsts = dwc2_readl(hsotg, GINTSTS);
181 dwc2_writel(hsotg, gintsts | GINTSTS_CONIDSTSCHNG, GINTSTS);
182 }
183 }
184
dwc2_drd_resume(struct dwc2_hsotg * hsotg)185 void dwc2_drd_resume(struct dwc2_hsotg *hsotg)
186 {
187 u32 gintsts, gintmsk;
188
189 if (hsotg->role_sw && !hsotg->params.external_id_pin_ctl) {
190 gintsts = dwc2_readl(hsotg, GINTSTS);
191 dwc2_writel(hsotg, gintsts | GINTSTS_CONIDSTSCHNG, GINTSTS);
192 gintmsk = dwc2_readl(hsotg, GINTMSK);
193 gintmsk |= GINTSTS_CONIDSTSCHNG;
194 dwc2_writel(hsotg, gintmsk, GINTMSK);
195 }
196 }
197
dwc2_drd_exit(struct dwc2_hsotg * hsotg)198 void dwc2_drd_exit(struct dwc2_hsotg *hsotg)
199 {
200 if (hsotg->role_sw)
201 usb_role_switch_unregister(hsotg->role_sw);
202 }
203