usb: dwc3: Added remote wake-up in xilinx glue driver

To support USB remote wake-up in xilinx glue driver, Added disable
regulator interface in core to enter in U3(suspend) state, and
introduced wake-up capability flag to enable the feature. when the
remote wakeup flag is enabled and the controller is in U3 state
(suspended), it requires suspend_clk to be active to detect wake-up
signaling driven on the link.

Added function registration and deregistration functionality for
remote wakeup feature from/to dwc3-host.

Signed-off-by: Piyush Mehta <piyush.mehta@xilinx.com>
State: pending

drivers/usb/dwc3/core.c

@@ -1849,6 +1849,18 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg)
 		break;
 	}
 
+	/* Put the core into D3 state */
+	if (dwc->dwc3_pmu) {
+		int ret;
+
+		ret = regulator_disable(dwc->dwc3_pmu);
+		if (ret) {
+			dev_err(dwc->dev,
+				"Failed to disable dwc3_pmu supply\n");
+			return ret;
+		}
+	}
+
 	return 0;
 }
 

drivers/usb/dwc3/core.h

@@ -29,6 +29,7 @@
 #include <linux/ulpi/interface.h>
 
 #include <linux/phy/phy.h>
+#include <../drivers/usb/host/xhci.h>
 
 #define DWC3_MSG_MAX	500
 
@@ -1473,6 +1474,9 @@ void dwc3_set_prtcap(struct dwc3 *dwc, u32 mode);
 void dwc3_set_mode(struct dwc3 *dwc, u32 mode);
 u32 dwc3_core_fifo_space(struct dwc3_ep *dep, u8 type);
 
+typedef void (*dwc3_wakeup_t)(struct device *dev, bool wakeup);
+void dwc3_host_wakeup_register(dwc3_wakeup_t func);
+
 #define DWC3_IP_IS(_ip)							\
 	(dwc->ip == _ip##_IP)
 

drivers/usb/dwc3/dwc3-xilinx.c

@@ -28,6 +28,8 @@
 
 #include <linux/phy/phy.h>
 
+#include "core.h"
+
 /* USB phy reset mask register */
 #define XLNX_USB_PHY_RST_EN			0x001C
 #define XLNX_PHY_RST_MASK			0x1
@@ -80,6 +82,7 @@ struct dwc3_xlnx {
 	struct regulator		*dwc3_pmu;
 	struct regulator_dev		*dwc3_xlnx_reg_rdev;
 	enum dwc3_xlnx_core_state	pmu_state;
+	bool				wakeup_capable;
 	struct reset_control		*crst;
 	bool				enable_d3_suspend;
 	enum usb_dr_mode		dr_mode;
@@ -159,6 +162,8 @@ static int dwc3_zynqmp_power_req(struct device *dev, bool on)
 		}
 
 		priv_data->pmu_state = D0_STATE;
+		/* disable D3 entry */
+		priv_data->enable_d3_suspend = false;
 	} else {
 		dev_dbg(priv_data->dev, "Trying to set power state to D3...\n");
 
@@ -500,6 +505,36 @@ static int dwc3_xlnx_init_zynqmp(struct dwc3_xlnx *priv_data)
 	return ret;
 }
 
+/* xilinx feature support functions */
+void dwc3_xilinx_wakeup_capable(struct device *dev, bool wakeup)
+{
+	struct device_node *node = of_node_get(dev->parent->of_node);
+
+	/* check for valid parent node */
+	while (node) {
+		if (of_device_is_compatible(node, "xlnx,zynqmp-dwc3") ||
+		    of_device_is_compatible(node, "xlnx,versal-dwc3"))
+			break;
+
+		/* get the next parent node */
+		node = of_get_next_parent(node);
+	}
+
+	if (node) {
+		struct platform_device *pdev_parent;
+		struct dwc3_xlnx *priv_data;
+
+		pdev_parent = of_find_device_by_node(node);
+		priv_data = platform_get_drvdata(pdev_parent);
+
+		/* Set wakeup capable as true or false */
+		priv_data->wakeup_capable = wakeup;
+
+		/* Allow D3 state if wakeup capable only */
+		priv_data->enable_d3_suspend = wakeup;
+	}
+}
+
 static const struct of_device_id dwc3_xlnx_of_match[] = {
 	{
 		.compatible = "xlnx,zynqmp-dwc3",
@@ -567,6 +602,8 @@ static int dwc3_xlnx_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 #endif
+	/* Register the dwc3-xilinx wakeup function to dwc3 host */
+	dwc3_host_wakeup_register(dwc3_xilinx_wakeup_capable);
 
 	ret = devm_clk_bulk_get_all(priv_data->dev, &priv_data->clks);
 	if (ret < 0)
@@ -607,6 +644,8 @@ static int dwc3_xlnx_remove(struct platform_device *pdev)
 
 	of_platform_depopulate(dev);
 
+	/* Unregister the dwc3-xilinx wakeup function from dwc3 host */
+	dwc3_host_wakeup_register(NULL);
 	clk_bulk_disable_unprepare(priv_data->num_clocks, priv_data->clks);
 	clk_bulk_put_all(priv_data->num_clocks, priv_data->clks);
 	priv_data->num_clocks = 0;
@@ -646,14 +685,15 @@ static int __maybe_unused dwc3_xlnx_suspend(struct device *dev)
 {
 	struct dwc3_xlnx *priv_data = dev_get_drvdata(dev);
 
+	if (!priv_data->wakeup_capable) {
 #ifdef CONFIG_PM
-	if (priv_data->dr_mode == USB_DR_MODE_PERIPHERAL)
-		/* Put the core into D3 */
-		dwc3_set_usb_core_power(dev, false);
+		if (priv_data->dr_mode == USB_DR_MODE_PERIPHERAL)
+			/* Put the core into D3 */
+			dwc3_set_usb_core_power(dev, false);
 #endif
-	/* Disable the clocks */
-	clk_bulk_disable(priv_data->num_clocks, priv_data->clks);
-
+		/* Disable the clocks */
+		clk_bulk_disable(priv_data->num_clocks, priv_data->clks);
+	}
 	return 0;
 }
 
@@ -662,6 +702,9 @@ static int __maybe_unused dwc3_xlnx_resume(struct device *dev)
 	struct dwc3_xlnx *priv_data = dev_get_drvdata(dev);
 	int ret;
 
+	if (priv_data->wakeup_capable)
+		return 0;
+
 #ifdef CONFIG_PM
 	if (priv_data->dr_mode == USB_DR_MODE_PERIPHERAL)
 		/* Put the core into D0 */

drivers/usb/dwc3/host.c

@@ -13,6 +13,21 @@
 
 #include "core.h"
 
+static dwc3_wakeup_t dwc3_wakeup_fn;
+
+ /* dwc3 host wakeup registration */
+void dwc3_host_wakeup_register(dwc3_wakeup_t func)
+{
+	dwc3_wakeup_fn = func;
+}
+
+/* callback function */
+void dwc3_host_wakeup_capable(struct device *dev, bool wakeup)
+{
+	if (dwc3_wakeup_fn)
+		dwc3_wakeup_fn(dev, wakeup);
+}
+
 static int dwc3_host_get_irq(struct dwc3 *dwc)
 {
 	struct platform_device	*dwc3_pdev = to_platform_device(dwc->dev);