drivers/usb/roles/intel-xhci-usb-role-switch.c

   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
  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
 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
 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
 198 static int 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         return 0;
 208 }
 209
 210 static const struct platform_device_id intel_xhci_usb_table[] = {
 211         { .name = DRV_NAME },
 212         {}
 213 };
 214 MODULE_DEVICE_TABLE(platform, intel_xhci_usb_table);
 215
 216 static struct platform_driver intel_xhci_usb_driver = {
 217         .driver = {
 218                 .name = DRV_NAME,
 219         },
 220         .id_table = intel_xhci_usb_table,
 221         .probe = intel_xhci_usb_probe,
 222         .remove = intel_xhci_usb_remove,
 223 };
 224
 225 module_platform_driver(intel_xhci_usb_driver);
 226
 227 MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
 228 MODULE_DESCRIPTION("Intel XHCI USB role switch driver");
 229 MODULE_LICENSE("GPL");