1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Intel XHCI (Cherry Trail, Broxton and others) USB OTG role switch driver
4 *
5 * Copyright (c) 2016-2017 Hans de Goede <hdegoede@redhat.com>
6 *
7 * Loosely based on android x86 kernel code which is:
8 *
9 * Copyright (C) 2014 Intel Corp.
10 *
11 * Author: Wu, Hao
12 */
13
14 #include <linux/acpi.h>
15 #include <linux/delay.h>
16 #include <linux/err.h>
17 #include <linux/io.h>
18 #include <linux/kernel.h>
19 #include <linux/module.h>
20 #include <linux/platform_device.h>
21 #include <linux/pm_runtime.h>
22 #include <linux/property.h>
23 #include <linux/usb/role.h>
24
25 /* register definition */
26 #define DUAL_ROLE_CFG0 0x68
27 #define SW_VBUS_VALID BIT(24)
28 #define SW_IDPIN_EN BIT(21)
29 #define SW_IDPIN BIT(20)
30 #define SW_SWITCH_EN BIT(16)
31
32 #define DRD_CONFIG_DYNAMIC 0
33 #define DRD_CONFIG_STATIC_HOST 1
34 #define DRD_CONFIG_STATIC_DEVICE 2
35 #define DRD_CONFIG_MASK 3
36
37 #define DUAL_ROLE_CFG1 0x6c
38 #define HOST_MODE BIT(29)
39
40 #define DUAL_ROLE_CFG1_POLL_TIMEOUT 1000
41
42 #define DRV_NAME "intel_xhci_usb_sw"
43
44 struct intel_xhci_usb_data {
45 struct device *dev;
46 struct usb_role_switch *role_sw;
47 void __iomem *base;
48 bool enable_sw_switch;
49 };
50
51 static const struct software_node intel_xhci_usb_node = {
52 "intel-xhci-usb-sw",
53 };
54
intel_xhci_usb_set_role(struct usb_role_switch * sw,enum usb_role role)55 static int intel_xhci_usb_set_role(struct usb_role_switch *sw,
56 enum usb_role role)
57 {
58 struct intel_xhci_usb_data *data = usb_role_switch_get_drvdata(sw);
59 unsigned long timeout;
60 acpi_status status;
61 u32 glk, val;
62 u32 drd_config = DRD_CONFIG_DYNAMIC;
63
64 /*
65 * On many CHT devices ACPI event (_AEI) handlers read / modify /
66 * write the cfg0 register, just like we do. Take the ACPI lock
67 * to avoid us racing with the AML code.
68 */
69 status = acpi_acquire_global_lock(ACPI_WAIT_FOREVER, &glk);
70 if (ACPI_FAILURE(status) && status != AE_NOT_CONFIGURED) {
71 dev_err(data->dev, "Error could not acquire lock\n");
72 return -EIO;
73 }
74
75 pm_runtime_get_sync(data->dev);
76
77 /*
78 * Set idpin value as requested.
79 * Since some devices rely on firmware setting DRD_CONFIG and
80 * SW_SWITCH_EN bits to be zero for role switch,
81 * do not set these bits for those devices.
82 */
83 val = readl(data->base + DUAL_ROLE_CFG0);
84 switch (role) {
85 case USB_ROLE_NONE:
86 val |= SW_IDPIN;
87 val &= ~SW_VBUS_VALID;
88 drd_config = DRD_CONFIG_DYNAMIC;
89 break;
90 case USB_ROLE_HOST:
91 val &= ~SW_IDPIN;
92 val &= ~SW_VBUS_VALID;
93 drd_config = DRD_CONFIG_STATIC_HOST;
94 break;
95 case USB_ROLE_DEVICE:
96 val |= SW_IDPIN;
97 val |= SW_VBUS_VALID;
98 drd_config = DRD_CONFIG_STATIC_DEVICE;
99 break;
100 }
101 val |= SW_IDPIN_EN;
102 if (data->enable_sw_switch) {
103 val &= ~DRD_CONFIG_MASK;
104 val |= SW_SWITCH_EN | drd_config;
105 }
106 writel(val, data->base + DUAL_ROLE_CFG0);
107
108 acpi_release_global_lock(glk);
109
110 /* In most case it takes about 600ms to finish mode switching */
111 timeout = jiffies + msecs_to_jiffies(DUAL_ROLE_CFG1_POLL_TIMEOUT);
112
113 /* Polling on CFG1 register to confirm mode switch.*/
114 do {
115 val = readl(data->base + DUAL_ROLE_CFG1);
116 if (!!(val & HOST_MODE) == (role == USB_ROLE_HOST)) {
117 pm_runtime_put(data->dev);
118 return 0;
119 }
120
121 /* Interval for polling is set to about 5 - 10 ms */
122 usleep_range(5000, 10000);
123 } while (time_before(jiffies, timeout));
124
125 pm_runtime_put(data->dev);
126
127 dev_warn(data->dev, "Timeout waiting for role-switch\n");
128 return -ETIMEDOUT;
129 }
130
intel_xhci_usb_get_role(struct usb_role_switch * sw)131 static enum usb_role intel_xhci_usb_get_role(struct usb_role_switch *sw)
132 {
133 struct intel_xhci_usb_data *data = usb_role_switch_get_drvdata(sw);
134 enum usb_role role;
135 u32 val;
136
137 pm_runtime_get_sync(data->dev);
138 val = readl(data->base + DUAL_ROLE_CFG0);
139 pm_runtime_put(data->dev);
140
141 if (!(val & SW_IDPIN))
142 role = USB_ROLE_HOST;
143 else if (val & SW_VBUS_VALID)
144 role = USB_ROLE_DEVICE;
145 else
146 role = USB_ROLE_NONE;
147
148 return role;
149 }
150
intel_xhci_usb_probe(struct platform_device * pdev)151 static int intel_xhci_usb_probe(struct platform_device *pdev)
152 {
153 struct usb_role_switch_desc sw_desc = { };
154 struct device *dev = &pdev->dev;
155 struct intel_xhci_usb_data *data;
156 struct resource *res;
157 int ret;
158
159 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
160 if (!data)
161 return -ENOMEM;
162
163 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
164 if (!res)
165 return -EINVAL;
166 data->base = devm_ioremap(dev, res->start, resource_size(res));
167 if (!data->base)
168 return -ENOMEM;
169
170 platform_set_drvdata(pdev, data);
171
172 ret = software_node_register(&intel_xhci_usb_node);
173 if (ret)
174 return ret;
175
176 sw_desc.set = intel_xhci_usb_set_role,
177 sw_desc.get = intel_xhci_usb_get_role,
178 sw_desc.allow_userspace_control = true,
179 sw_desc.fwnode = software_node_fwnode(&intel_xhci_usb_node);
180 sw_desc.driver_data = data;
181
182 data->dev = dev;
183 data->enable_sw_switch = !device_property_read_bool(dev,
184 "sw_switch_disable");
185
186 data->role_sw = usb_role_switch_register(dev, &sw_desc);
187 if (IS_ERR(data->role_sw)) {
188 fwnode_handle_put(sw_desc.fwnode);
189 return PTR_ERR(data->role_sw);
190 }
191
192 pm_runtime_set_active(dev);
193 pm_runtime_enable(dev);
194
195 return 0;
196 }
197
intel_xhci_usb_remove(struct platform_device * pdev)198 static void intel_xhci_usb_remove(struct platform_device *pdev)
199 {
200 struct intel_xhci_usb_data *data = platform_get_drvdata(pdev);
201
202 pm_runtime_disable(&pdev->dev);
203
204 usb_role_switch_unregister(data->role_sw);
205 fwnode_handle_put(software_node_fwnode(&intel_xhci_usb_node));
206 }
207
208 static const struct platform_device_id intel_xhci_usb_table[] = {
209 { .name = DRV_NAME },
210 {}
211 };
212 MODULE_DEVICE_TABLE(platform, intel_xhci_usb_table);
213
214 static struct platform_driver intel_xhci_usb_driver = {
215 .driver = {
216 .name = DRV_NAME,
217 },
218 .id_table = intel_xhci_usb_table,
219 .probe = intel_xhci_usb_probe,
220 .remove_new = intel_xhci_usb_remove,
221 };
222
223 module_platform_driver(intel_xhci_usb_driver);
224
225 MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
226 MODULE_DESCRIPTION("Intel XHCI USB role switch driver");
227 MODULE_LICENSE("GPL");
228