phy: rockchip-inno-usb3: workaround for USB3 PHY disconnection det issue

The rk322xh USB3 PHY has a problem to detect disconnection,
it loses the ability to detect an absence of a far-end
receiver termination specified in USB3 spec Table 6-21,
and this causes the linkstate to change between SS.Inactive
and Polling state, but not return to correct state Rx.detect.

To workaround this bug, we depends on the hub_event to
detect the port linkstate change and do soft disconnect.
And then do USB3 PHY reset and reinit HCD to recovery
the whole USB3.

The workaround process is:
Plug out USB3 device -> hub_event detect PLC and find
USB 3.0 port in the Inactive -> call usb_remove_device()
to do soft disconnect -> call usb_phy_notify_connect()
-> send notifier to DWC3 controller driver to do USB3
PHY reset and reinit HCD.

Change-Id: Icb975581c6fbbb34a7da90ddca47e04a46e5da48
Signed-off-by: William Wu <[email protected]>

drivers/phy/phy-rockchip-inno-usb3.c

@@ -30,6 +30,7 @@
 #include <linux/platform_device.h>
 #include <linux/regmap.h>
 #include <linux/reset.h>
+#include <linux/usb/phy.h>
 
 #define U3PHY_PORT_NUM	2
 #define U3PHY_MAX_CLKS	4
@@ -140,6 +141,7 @@ struct rockchip_u3phy {
 	struct rockchip_u3phy_apbcfg apbcfg;
 	const struct rockchip_u3phy_cfg *cfgs;
 	struct rockchip_u3phy_port ports[U3PHY_PORT_NUM];
+	struct usb_phy usb_phy;
 };
 
 static inline int param_write(void __iomem *base,
@@ -650,6 +652,43 @@ static int rockchip_u3phy_port_init(struct rockchip_u3phy *u3phy,
 	return 0;
 }
 
+static int rockchip_u3phy_on_init(struct usb_phy *usb_phy)
+{
+	struct rockchip_u3phy *u3phy =
+		container_of(usb_phy, struct rockchip_u3phy, usb_phy);
+
+	reset_control_deassert(u3phy->rsts[U3_POR_RSTN]);
+	usleep_range(250, 300);
+	reset_control_deassert(u3phy->rsts[PIPE_MAC_RSTN]);
+
+	return 0;
+}
+
+static void rockchip_u3phy_on_shutdown(struct usb_phy *usb_phy)
+{
+	struct rockchip_u3phy *u3phy =
+		container_of(usb_phy, struct rockchip_u3phy, usb_phy);
+
+	reset_control_assert(u3phy->rsts[U3_POR_RSTN]);
+	reset_control_assert(u3phy->rsts[PIPE_MAC_RSTN]);
+	usleep_range(15, 20);
+}
+
+static int rockchip_u3phy_on_disconnect(struct usb_phy *usb_phy,
+					enum usb_device_speed speed)
+{
+	struct rockchip_u3phy *u3phy =
+		container_of(usb_phy, struct rockchip_u3phy, usb_phy);
+
+	dev_info(u3phy->dev, "%s device has disconnected\n",
+		 (speed == USB_SPEED_SUPER) ? "U3" : "UW/U2/U1.1/U1");
+
+	if (speed == USB_SPEED_SUPER)
+		atomic_notifier_call_chain(&usb_phy->notifier, 0, NULL);
+
+	return 0;
+}
+
 static int rockchip_u3phy_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -742,6 +781,13 @@ static int rockchip_u3phy_probe(struct platform_device *pdev)
 	rockchip_u3phy_rest_deassert(u3phy, U3PHY_MAC_RST);
 	rockchip_u3phy_clk_disable(u3phy);
 
+	u3phy->usb_phy.dev = dev;
+	u3phy->usb_phy.init = rockchip_u3phy_on_init;
+	u3phy->usb_phy.shutdown = rockchip_u3phy_on_shutdown;
+	u3phy->usb_phy.notify_disconnect = rockchip_u3phy_on_disconnect;
+	usb_add_phy(&u3phy->usb_phy, USB_PHY_TYPE_USB3);
+	ATOMIC_INIT_NOTIFIER_HEAD(&u3phy->usb_phy.notifier);
+
 	dev_info(dev, "Rockchip u3phy initialized successfully\n");
 	return 0;