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/iopoll.h>
11 #include <linux/platform_device.h>
12 #include <linux/usb/role.h>
13 #include "core.h"
14
dwc2_ovr_init(struct dwc2_hsotg * hsotg)15 static void dwc2_ovr_init(struct dwc2_hsotg *hsotg)
16 {
17 unsigned long flags;
18 u32 gotgctl;
19
20 spin_lock_irqsave(&hsotg->lock, flags);
21
22 gotgctl = dwc2_readl(hsotg, GOTGCTL);
23 gotgctl |= GOTGCTL_BVALOEN | GOTGCTL_AVALOEN | GOTGCTL_VBVALOEN;
24 gotgctl |= GOTGCTL_DBNCE_FLTR_BYPASS;
25 gotgctl &= ~(GOTGCTL_BVALOVAL | GOTGCTL_AVALOVAL | GOTGCTL_VBVALOVAL);
26 dwc2_writel(hsotg, gotgctl, GOTGCTL);
27
28 dwc2_force_mode(hsotg, false);
29
30 spin_unlock_irqrestore(&hsotg->lock, flags);
31 }
32
dwc2_ovr_avalid(struct dwc2_hsotg * hsotg,bool valid)33 static int dwc2_ovr_avalid(struct dwc2_hsotg *hsotg, bool valid)
34 {
35 u32 gotgctl = dwc2_readl(hsotg, GOTGCTL);
36
37 /* Check if A-Session is already in the right state */
38 if ((valid && (gotgctl & GOTGCTL_ASESVLD)) ||
39 (!valid && !(gotgctl & GOTGCTL_ASESVLD)))
40 return -EALREADY;
41
42 if (valid)
43 gotgctl |= GOTGCTL_AVALOVAL | GOTGCTL_VBVALOVAL;
44 else
45 gotgctl &= ~(GOTGCTL_AVALOVAL | GOTGCTL_VBVALOVAL);
46 dwc2_writel(hsotg, gotgctl, GOTGCTL);
47
48 return 0;
49 }
50
dwc2_ovr_bvalid(struct dwc2_hsotg * hsotg,bool valid)51 static int dwc2_ovr_bvalid(struct dwc2_hsotg *hsotg, bool valid)
52 {
53 u32 gotgctl = dwc2_readl(hsotg, GOTGCTL);
54
55 /* Check if B-Session is already in the right state */
56 if ((valid && (gotgctl & GOTGCTL_BSESVLD)) ||
57 (!valid && !(gotgctl & GOTGCTL_BSESVLD)))
58 return -EALREADY;
59
60 if (valid)
61 gotgctl |= GOTGCTL_BVALOVAL | GOTGCTL_VBVALOVAL;
62 else
63 gotgctl &= ~(GOTGCTL_BVALOVAL | GOTGCTL_VBVALOVAL);
64 dwc2_writel(hsotg, gotgctl, GOTGCTL);
65
66 return 0;
67 }
68
dwc2_drd_role_sw_set(struct usb_role_switch * sw,enum usb_role role)69 static int dwc2_drd_role_sw_set(struct usb_role_switch *sw, enum usb_role role)
70 {
71 struct dwc2_hsotg *hsotg = usb_role_switch_get_drvdata(sw);
72 unsigned long flags;
73 int already = 0;
74
75 /* Skip session not in line with dr_mode */
76 if ((role == USB_ROLE_DEVICE && hsotg->dr_mode == USB_DR_MODE_HOST) ||
77 (role == USB_ROLE_HOST && hsotg->dr_mode == USB_DR_MODE_PERIPHERAL))
78 return -EINVAL;
79
80 #if IS_ENABLED(CONFIG_USB_DWC2_PERIPHERAL) || \
81 IS_ENABLED(CONFIG_USB_DWC2_DUAL_ROLE)
82 /* Skip session if core is in test mode */
83 if (role == USB_ROLE_NONE && hsotg->test_mode) {
84 dev_dbg(hsotg->dev, "Core is in test mode\n");
85 return -EBUSY;
86 }
87 #endif
88
89 spin_lock_irqsave(&hsotg->lock, flags);
90
91 if (role == USB_ROLE_HOST) {
92 already = dwc2_ovr_avalid(hsotg, true);
93 } else if (role == USB_ROLE_DEVICE) {
94 already = dwc2_ovr_bvalid(hsotg, true);
95 /* This clear DCTL.SFTDISCON bit */
96 dwc2_hsotg_core_connect(hsotg);
97 } else {
98 if (dwc2_is_device_mode(hsotg)) {
99 if (!dwc2_ovr_bvalid(hsotg, false))
100 /* This set DCTL.SFTDISCON bit */
101 dwc2_hsotg_core_disconnect(hsotg);
102 } else {
103 dwc2_ovr_avalid(hsotg, false);
104 }
105 }
106
107 spin_unlock_irqrestore(&hsotg->lock, flags);
108
109 if (!already && hsotg->dr_mode == USB_DR_MODE_OTG)
110 /* This will raise a Connector ID Status Change Interrupt */
111 dwc2_force_mode(hsotg, role == USB_ROLE_HOST);
112
113 dev_dbg(hsotg->dev, "%s-session valid\n",
114 role == USB_ROLE_NONE ? "No" :
115 role == USB_ROLE_HOST ? "A" : "B");
116
117 return 0;
118 }
119
dwc2_drd_init(struct dwc2_hsotg * hsotg)120 int dwc2_drd_init(struct dwc2_hsotg *hsotg)
121 {
122 struct usb_role_switch_desc role_sw_desc = {0};
123 struct usb_role_switch *role_sw;
124 int ret;
125
126 if (!device_property_read_bool(hsotg->dev, "usb-role-switch"))
127 return 0;
128
129 role_sw_desc.driver_data = hsotg;
130 role_sw_desc.fwnode = dev_fwnode(hsotg->dev);
131 role_sw_desc.set = dwc2_drd_role_sw_set;
132 role_sw_desc.allow_userspace_control = true;
133
134 role_sw = usb_role_switch_register(hsotg->dev, &role_sw_desc);
135 if (IS_ERR(role_sw)) {
136 ret = PTR_ERR(role_sw);
137 dev_err(hsotg->dev,
138 "failed to register role switch: %d\n", ret);
139 return ret;
140 }
141
142 hsotg->role_sw = role_sw;
143
144 /* Enable override and initialize values */
145 dwc2_ovr_init(hsotg);
146
147 return 0;
148 }
149
dwc2_drd_suspend(struct dwc2_hsotg * hsotg)150 void dwc2_drd_suspend(struct dwc2_hsotg *hsotg)
151 {
152 u32 gintsts, gintmsk;
153
154 if (hsotg->role_sw && !hsotg->params.external_id_pin_ctl) {
155 gintmsk = dwc2_readl(hsotg, GINTMSK);
156 gintmsk &= ~GINTSTS_CONIDSTSCHNG;
157 dwc2_writel(hsotg, gintmsk, GINTMSK);
158 gintsts = dwc2_readl(hsotg, GINTSTS);
159 dwc2_writel(hsotg, gintsts | GINTSTS_CONIDSTSCHNG, GINTSTS);
160 }
161 }
162
dwc2_drd_resume(struct dwc2_hsotg * hsotg)163 void dwc2_drd_resume(struct dwc2_hsotg *hsotg)
164 {
165 u32 gintsts, gintmsk;
166
167 if (hsotg->role_sw && !hsotg->params.external_id_pin_ctl) {
168 gintsts = dwc2_readl(hsotg, GINTSTS);
169 dwc2_writel(hsotg, gintsts | GINTSTS_CONIDSTSCHNG, GINTSTS);
170 gintmsk = dwc2_readl(hsotg, GINTMSK);
171 gintmsk |= GINTSTS_CONIDSTSCHNG;
172 dwc2_writel(hsotg, gintmsk, GINTMSK);
173 }
174 }
175
dwc2_drd_exit(struct dwc2_hsotg * hsotg)176 void dwc2_drd_exit(struct dwc2_hsotg *hsotg)
177 {
178 if (hsotg->role_sw)
179 usb_role_switch_unregister(hsotg->role_sw);
180 }
181
