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 | |
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, value: gotgctl, GOTGCTL); |
35 | |
36 | spin_unlock_irqrestore(lock: &hsotg->lock, flags); |
37 | |
38 | dwc2_force_mode(hsotg, host: (hsotg->dr_mode == USB_DR_MODE_HOST) || |
39 | (hsotg->role_sw_default_mode == USB_DR_MODE_HOST)); |
40 | } |
41 | |
42 | static 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, value: gotgctl, GOTGCTL); |
60 | |
61 | return 0; |
62 | } |
63 | |
64 | static 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, value: gotgctl, GOTGCTL); |
82 | |
83 | return 0; |
84 | } |
85 | |
86 | static 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(clk: 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, valid: true); |
132 | } else if (role == USB_ROLE_DEVICE) { |
133 | already = dwc2_ovr_bvalid(hsotg, valid: 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, valid: false)) |
141 | /* This set DCTL.SFTDISCON bit */ |
142 | dwc2_hsotg_core_disconnect(hsotg); |
143 | } else { |
144 | dwc2_ovr_avalid(hsotg, valid: false); |
145 | } |
146 | } |
147 | |
148 | spin_unlock_irqrestore(lock: &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, host: role == USB_ROLE_HOST); |
153 | |
154 | if (!hsotg->ll_hw_enabled && hsotg->clk) |
155 | clk_disable_unprepare(clk: 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 | |
164 | int 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(dev: hsotg->dev, propname: "usb-role-switch" )) |
171 | return 0; |
172 | |
173 | hsotg->role_sw_default_mode = usb_get_role_switch_default_mode(dev: 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(parent: hsotg->dev, desc: &role_sw_desc); |
180 | if (IS_ERR(ptr: role_sw)) { |
181 | ret = PTR_ERR(ptr: 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 | |
195 | void 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, value: gintmsk, GINTMSK); |
203 | gintsts = dwc2_readl(hsotg, GINTSTS); |
204 | dwc2_writel(hsotg, value: gintsts | GINTSTS_CONIDSTSCHNG, GINTSTS); |
205 | } |
206 | } |
207 | |
208 | void 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(sw: 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, valid: true); |
227 | else if (role == USB_ROLE_DEVICE) |
228 | dwc2_ovr_bvalid(hsotg, valid: true); |
229 | |
230 | dwc2_force_mode(hsotg, host: 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, value: gintsts | GINTSTS_CONIDSTSCHNG, GINTSTS); |
240 | gintmsk = dwc2_readl(hsotg, GINTMSK); |
241 | gintmsk |= GINTSTS_CONIDSTSCHNG; |
242 | dwc2_writel(hsotg, value: gintmsk, GINTMSK); |
243 | } |
244 | } |
245 | |
246 | void dwc2_drd_exit(struct dwc2_hsotg *hsotg) |
247 | { |
248 | if (hsotg->role_sw) |
249 | usb_role_switch_unregister(sw: hsotg->role_sw); |
250 | } |
251 | |