usb: roles: intel: Enable static DRD mode for role switch

Enable static DRD mode in Intel platforms which guarantees
successful role switch all the time. This fixes issues like
software role switch failure after cold boot and issue with
role switch when USB 3.0 cable is used. But, do not enable
static DRD mode for Cherrytrail devices which rely on firmware
for role switch.

Signed-off-by: Saranya Gopal <saranya.gopal@intel.com>
Signed-off-by: Balaji Manoharan <m.balaji@intel.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Tested-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/1567079760-24822-2-git-send-email-saranya.gopal@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/roles/intel-xhci-usb-role-switch.c b/drivers/usb/roles/intel-xhci-usb-role-switch.c
index 277de96181f9a056091aaca586831ece879f1d60..88d041601c51e08fc37244c249b5ac016f8d25dc 100644 (file)
--- a/drivers/usb/roles/intel-xhci-usb-role-switch.c
+++ b/drivers/usb/roles/intel-xhci-usb-role-switch.c
@@ -19,6 +19,7 @@
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
+#include <linux/property.h>
 #include <linux/usb/role.h>
 
 /* register definition */
@@ -26,6 +27,12 @@
 #define SW_VBUS_VALID                  BIT(24)
 #define SW_IDPIN_EN                    BIT(21)
 #define SW_IDPIN                       BIT(20)
+#define SW_SWITCH_EN                   BIT(16)
+
+#define DRD_CONFIG_DYNAMIC             0
+#define DRD_CONFIG_STATIC_HOST         1
+#define DRD_CONFIG_STATIC_DEVICE       2
+#define DRD_CONFIG_MASK                        3
 
 #define DUAL_ROLE_CFG1                 0x6c
 #define HOST_MODE                      BIT(29)
@@ -37,6 +44,7 @@
 struct intel_xhci_usb_data {
        struct usb_role_switch *role_sw;
        void __iomem *base;
+       bool enable_sw_switch;
 };
 
 static int intel_xhci_usb_set_role(struct device *dev, enum usb_role role)
@@ -45,6 +53,7 @@ static int intel_xhci_usb_set_role(struct device *dev, enum usb_role role)
        unsigned long timeout;
        acpi_status status;
        u32 glk, val;
+       u32 drd_config = DRD_CONFIG_DYNAMIC;
 
        /*
         * On many CHT devices ACPI event (_AEI) handlers read / modify /
@@ -59,24 +68,35 @@ static int intel_xhci_usb_set_role(struct device *dev, enum usb_role role)
 
        pm_runtime_get_sync(dev);
 
-       /* Set idpin value as requested */
+       /*
+        * Set idpin value as requested.
+        * Since some devices rely on firmware setting DRD_CONFIG and
+        * SW_SWITCH_EN bits to be zero for role switch,
+        * do not set these bits for those devices.
+        */
        val = readl(data->base + DUAL_ROLE_CFG0);
        switch (role) {
        case USB_ROLE_NONE:
                val |= SW_IDPIN;
                val &= ~SW_VBUS_VALID;
+               drd_config = DRD_CONFIG_DYNAMIC;
                break;
        case USB_ROLE_HOST:
                val &= ~SW_IDPIN;
                val &= ~SW_VBUS_VALID;
+               drd_config = DRD_CONFIG_STATIC_HOST;
                break;
        case USB_ROLE_DEVICE:
                val |= SW_IDPIN;
                val |= SW_VBUS_VALID;
+               drd_config = DRD_CONFIG_STATIC_DEVICE;
                break;
        }
        val |= SW_IDPIN_EN;
-
+       if (data->enable_sw_switch) {
+               val &= ~DRD_CONFIG_MASK;
+               val |= SW_SWITCH_EN | drd_config;
+       }
        writel(val, data->base + DUAL_ROLE_CFG0);
 
        acpi_release_global_lock(glk);
@@ -147,6 +167,9 @@ static int intel_xhci_usb_probe(struct platform_device *pdev)
 
        platform_set_drvdata(pdev, data);
 
+       data->enable_sw_switch = !device_property_read_bool(dev,
+                                               "sw_switch_disable");
+
        data->role_sw = usb_role_switch_register(dev, &sw_desc);
        if (IS_ERR(data->role_sw))
                return PTR_ERR(data->role_sw);