0071-roles-Enable-static-DRD-mode-for-role-switch-in.patch

From 99b6186fbef953d5463c612cbfc00c716841997e Mon Sep 17 00:00:00 2001
From: Saranya Gopal <saranya.gopal@intel.com>
Date: Fri, 5 Oct 2018 15:20:15 +0530
Subject: [PATCH 03/15] roles: Enable static DRD mode for role switch in Intel
 platforms

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 3.0 OTG 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: M, Balaji <m.balaji@intel.com>
[ heikki: Minor cleanup ]
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
---
 .../usb/roles/intel-xhci-usb-role-switch.c    | 26 ++++++++++++++++++-
 1 file changed, 25 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/roles/intel-xhci-usb-role-switch.c b/drivers/usb/roles/intel-xhci-usb-role-switch.c
index 277de96181f9..f9ed262c15b3 100644
--- 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 +27,9 @@
 #define SW_VBUS_VALID			BIT(24)
 #define SW_IDPIN_EN			BIT(21)
 #define SW_IDPIN			BIT(20)
+#define SW_SWITCH_EN_CFG0		BIT(16)
+#define SW_DRD_STATIC_HOST_CFG0		1
+#define SW_DRD_STATIC_DEV_CFG0		2
 
 #define DUAL_ROLE_CFG1			0x6c
 #define HOST_MODE			BIT(29)
@@ -37,6 +41,7 @@
 struct intel_xhci_usb_data {
 	struct usb_role_switch *role_sw;
 	void __iomem *base;
+	bool disable_sw_switch;
 };
 
 static int intel_xhci_usb_set_role(struct device *dev, enum usb_role role)
@@ -59,23 +64,39 @@ 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_CFG0 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;
+		val &= ~(SW_DRD_STATIC_DEV_CFG0 | SW_DRD_STATIC_HOST_CFG0);
 		break;
 	case USB_ROLE_HOST:
 		val &= ~SW_IDPIN;
 		val &= ~SW_VBUS_VALID;
+		if (!data->disable_sw_switch) {
+			val &= ~SW_DRD_STATIC_DEV_CFG0;
+			val |= SW_DRD_STATIC_HOST_CFG0;
+		}
 		break;
 	case USB_ROLE_DEVICE:
 		val |= SW_IDPIN;
 		val |= SW_VBUS_VALID;
+		if (!data->disable_sw_switch) {
+			val &= ~SW_DRD_STATIC_HOST_CFG0;
+			val |= SW_DRD_STATIC_DEV_CFG0;
+		}
 		break;
 	}
 	val |= SW_IDPIN_EN;
+	if (!data->disable_sw_switch)
+		val |= SW_SWITCH_EN_CFG0;
 
 	writel(val, data->base + DUAL_ROLE_CFG0);
 
@@ -147,6 +168,9 @@ static int intel_xhci_usb_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, data);
 
+	data->disable_sw_switch = device_property_read_bool(dev,
+						"drd,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);
-- 
2.19.1