[PATCH v9 5/5] usb: dwc3: add rockchip specific glue layer

[William Wu]

Add rockchip specific glue layer to support USB3 Peripheral mode
and Host mode on rockchip platforms (e.g. rk3399).

The DesignWare USB3 integrated in rockchip SoCs is a configurable
IP Core which can be instantiated as Dual-Role Device (DRD), Host
Only (XHCI) and Peripheral Only configurations.

We use extcon notifier to manage usb cable detection and mode switch.
Enable DWC3 PM runtime auto suspend to allow core enter runtime_suspend
if USB cable is dettached. For host mode, it requires to keep whole
DWC3 controller in reset state to hold pipe power state in P2 before
initializing PHY. And it need to reconfigure USB PHY interface of DWC3
core after deassert DWC3 controller reset.

The current driver supports Host only and Peripheral Only well, for
now, we will add support for OTG after we have it all stabilized.

Signed-off-by: William Wu <william.wu@xxxxxxxxxxxxxx>
---
 drivers/usb/dwc3/Kconfig         |   9 +
 drivers/usb/dwc3/Makefile        |   1 +
 drivers/usb/dwc3/core.c          |   2 +-
 drivers/usb/dwc3/core.h          |   1 +
 drivers/usb/dwc3/dwc3-rockchip.c | 441 +++++++++++++++++++++++++++++++++++++++
 5 files changed, 453 insertions(+), 1 deletion(-)
 create mode 100644 drivers/usb/dwc3/dwc3-rockchip.c

diff --git a/drivers/usb/dwc3/Kconfig b/drivers/usb/dwc3/Kconfig
index a64ce1c..3d5ec30 100644
--- a/drivers/usb/dwc3/Kconfig
+++ b/drivers/usb/dwc3/Kconfig
@@ -96,6 +96,15 @@ config USB_DWC3_OF_SIMPLE
 	 Currently supports Xilinx and Qualcomm DWC USB3 IP.
 	 Say 'Y' or 'M' if you have one such device.
 
+config USB_DWC3_ROCKCHIP
+	tristate "Rockchip Platforms"
+	depends on EXTCON && (ARCH_ROCKCHIP || COMPILE_TEST)
+	depends on OF
+	default USB_DWC3
+	help
+	  Support of USB2/3 functionality in Rockchip platforms.
+	  say 'Y' or 'M' if you have one such device.
+
 config USB_DWC3_ST
 	tristate "STMicroelectronics Platforms"
 	depends on ARCH_STI && OF
diff --git a/drivers/usb/dwc3/Makefile b/drivers/usb/dwc3/Makefile
index 22420e1..86fc4fd 100644
--- a/drivers/usb/dwc3/Makefile
+++ b/drivers/usb/dwc3/Makefile
@@ -38,4 +38,5 @@ obj-$(CONFIG_USB_DWC3_EXYNOS)		+= dwc3-exynos.o
 obj-$(CONFIG_USB_DWC3_PCI)		+= dwc3-pci.o
 obj-$(CONFIG_USB_DWC3_KEYSTONE)		+= dwc3-keystone.o
 obj-$(CONFIG_USB_DWC3_OF_SIMPLE)	+= dwc3-of-simple.o
+obj-$(CONFIG_USB_DWC3_ROCKCHIP)		+= dwc3-rockchip.o
 obj-$(CONFIG_USB_DWC3_ST)		+= dwc3-st.o
diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index e887b38..3da6215 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -405,7 +405,7 @@ static void dwc3_cache_hwparams(struct dwc3 *dwc)
  * initialized. The PHY interfaces and the PHYs get initialized together with
  * the core in dwc3_core_init.
  */
-static int dwc3_phy_setup(struct dwc3 *dwc)
+int dwc3_phy_setup(struct dwc3 *dwc)
 {
 	u32 reg;
 	int ret;
diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index 3d94acd..79403ff 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -1123,6 +1123,7 @@ struct dwc3_gadget_ep_cmd_params {
 /* prototypes */
 void dwc3_set_mode(struct dwc3 *dwc, u32 mode);
 u32 dwc3_core_fifo_space(struct dwc3_ep *dep, u8 type);
+int dwc3_phy_setup(struct dwc3 *dwc);
 
 /* check whether we are on the DWC_usb31 core */
 static inline bool dwc3_is_usb31(struct dwc3 *dwc)
diff --git a/drivers/usb/dwc3/dwc3-rockchip.c b/drivers/usb/dwc3/dwc3-rockchip.c
new file mode 100644
index 0000000..632bbb9
--- /dev/null
+++ b/drivers/usb/dwc3/dwc3-rockchip.c
@@ -0,0 +1,441 @@
+/**
+ * dwc3-rockchip.c - Rockchip Specific Glue layer
+ *
+ * Copyright (C) Fuzhou Rockchip Electronics Co.Ltd
+ *
+ * Authors: William Wu <william.wu@xxxxxxxxxxxxxx>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2  of
+ * the License as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/platform_device.h>
+#include <linux/dma-mapping.h>
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/pm_runtime.h>
+#include <linux/extcon.h>
+#include <linux/reset.h>
+#include <linux/usb.h>
+#include <linux/usb/hcd.h>
+
+#include "core.h"
+#include "io.h"
+
+#define DWC3_ROCKCHIP_AUTOSUSPEND_DELAY  500 /* ms */
+
+struct dwc3_rockchip {
+	int			num_clocks;
+	struct device		*dev;
+	struct clk		**clks;
+	struct dwc3		*dwc;
+	struct reset_control	*otg_rst;
+	struct extcon_dev	*edev;
+	struct notifier_block	device_nb;
+	struct notifier_block	host_nb;
+	struct work_struct	otg_work;
+};
+
+static int dwc3_rockchip_device_notifier(struct notifier_block *nb,
+					 unsigned long event, void *ptr)
+{
+	struct dwc3_rockchip *rockchip =
+		container_of(nb, struct dwc3_rockchip, device_nb);
+
+	schedule_work(&rockchip->otg_work);
+
+	return NOTIFY_DONE;
+}
+
+static int dwc3_rockchip_host_notifier(struct notifier_block *nb,
+				       unsigned long event, void *ptr)
+{
+	struct dwc3_rockchip *rockchip =
+		container_of(nb, struct dwc3_rockchip, host_nb);
+
+	schedule_work(&rockchip->otg_work);
+
+	return NOTIFY_DONE;
+}
+
+static void dwc3_rockchip_otg_extcon_evt_work(struct work_struct *work)
+{
+	struct dwc3_rockchip	*rockchip =
+		container_of(work, struct dwc3_rockchip, otg_work);
+	struct dwc3		*dwc = rockchip->dwc;
+	struct extcon_dev	*edev = rockchip->edev;
+	struct usb_hcd		*hcd;
+	unsigned long		flags;
+	int			ret;
+	u32			reg;
+
+	if (extcon_get_cable_state_(edev, EXTCON_USB) > 0) {
+		if (dwc->connected)
+			return;
+
+		/*
+		 * If dr_mode is host only, never to set
+		 * the mode to the peripheral mode.
+		 */
+		if (WARN_ON(dwc->dr_mode == USB_DR_MODE_HOST))
+			return;
+
+		pm_runtime_get_sync(dwc->dev);
+
+		spin_lock_irqsave(&dwc->lock, flags);
+		dwc->connected = true;
+		dwc3_set_mode(dwc, DWC3_GCTL_PRTCAP_DEVICE);
+		spin_unlock_irqrestore(&dwc->lock, flags);
+
+		pm_runtime_put_sync(dwc->dev);
+
+		dev_info(rockchip->dev, "USB peripheral connected\n");
+	} else if (extcon_get_cable_state_(edev, EXTCON_USB_HOST) > 0) {
+		if (dwc->connected)
+			return;
+
+		/*
+		 * If dr_mode is device only, never to
+		 * set the mode to the host mode.
+		 */
+		if (WARN_ON(dwc->dr_mode == USB_DR_MODE_PERIPHERAL))
+			return;
+
+		reset_control_assert(rockchip->otg_rst);
+
+		ret = phy_power_on(dwc->usb2_generic_phy);
+		if (ret < 0)
+			return;
+
+		ret = phy_power_on(dwc->usb3_generic_phy);
+		if (ret < 0)
+			return;
+
+		reset_control_deassert(rockchip->otg_rst);
+
+		dwc3_phy_setup(dwc);
+
+		hcd = dev_get_drvdata(&dwc->xhci->dev);
+
+		spin_lock_irqsave(&dwc->lock, flags);
+		dwc3_set_mode(dwc, DWC3_GCTL_PRTCAP_HOST);
+		dwc->connected = true;
+		spin_unlock_irqrestore(&dwc->lock, flags);
+
+		if (hcd->state == HC_STATE_HALT) {
+			usb_add_hcd(hcd, hcd->irq, IRQF_SHARED);
+			usb_add_hcd(hcd->shared_hcd, hcd->irq, IRQF_SHARED);
+		}
+
+		dev_info(rockchip->dev, "USB HOST connected\n");
+	} else {
+		if (!dwc->connected)
+			return;
+
+		reg = dwc3_readl(dwc->regs, DWC3_GCTL);
+
+		if (DWC3_GCTL_PRTCAP(reg) == DWC3_GCTL_PRTCAP_HOST ||
+		    DWC3_GCTL_PRTCAP(reg) == DWC3_GCTL_PRTCAP_OTG) {
+			hcd = dev_get_drvdata(&dwc->xhci->dev);
+
+			if (hcd->state != HC_STATE_HALT) {
+				usb_remove_hcd(hcd->shared_hcd);
+				usb_remove_hcd(hcd);
+			}
+
+			phy_power_off(dwc->usb2_generic_phy);
+			phy_power_off(dwc->usb3_generic_phy);
+		}
+
+		spin_lock_irqsave(&dwc->lock, flags);
+		dwc->connected = false;
+		spin_unlock_irqrestore(&dwc->lock, flags);
+
+		dev_info(rockchip->dev, "USB unconnected\n");
+	}
+}
+
+static int dwc3_rockchip_extcon_register(struct dwc3_rockchip *rockchip)
+{
+	int			ret;
+	struct device		*dev = rockchip->dev;
+	struct extcon_dev	*edev;
+
+	if (device_property_read_bool(dev, "extcon")) {
+		edev = extcon_get_edev_by_phandle(dev, 0);
+		if (IS_ERR(edev)) {
+			if (PTR_ERR(edev) != -EPROBE_DEFER)
+				dev_err(dev, "couldn't get extcon device\n");
+			return PTR_ERR(edev);
+		}
+
+		INIT_WORK(&rockchip->otg_work,
+			  dwc3_rockchip_otg_extcon_evt_work);
+
+		rockchip->device_nb.notifier_call =
+				dwc3_rockchip_device_notifier;
+		ret = extcon_register_notifier(edev, EXTCON_USB,
+					       &rockchip->device_nb);
+		if (ret < 0) {
+			dev_err(dev, "failed to register notifier for USB\n");
+			return ret;
+		}
+
+		rockchip->host_nb.notifier_call =
+				dwc3_rockchip_host_notifier;
+		ret = extcon_register_notifier(edev, EXTCON_USB_HOST,
+					       &rockchip->host_nb);
+		if (ret < 0) {
+			dev_err(dev, "failed to register notifier for USB HOST\n");
+			extcon_unregister_notifier(edev, EXTCON_USB,
+						   &rockchip->device_nb);
+			return ret;
+		}
+
+		rockchip->edev = edev;
+	}
+
+	return 0;
+}
+
+static void dwc3_rockchip_extcon_unregister(struct dwc3_rockchip *rockchip)
+{
+	if (!rockchip->edev)
+		return;
+
+	extcon_unregister_notifier(rockchip->edev, EXTCON_USB,
+				   &rockchip->device_nb);
+	extcon_unregister_notifier(rockchip->edev, EXTCON_USB_HOST,
+				   &rockchip->host_nb);
+}
+
+static int dwc3_rockchip_probe(struct platform_device *pdev)
+{
+	struct dwc3_rockchip	*rockchip;
+	struct device		*dev = &pdev->dev;
+	struct device_node	*np = dev->of_node, *child;
+	struct platform_device	*child_pdev;
+
+	unsigned int		count;
+	int			ret;
+	int			i;
+
+	rockchip = devm_kzalloc(dev, sizeof(*rockchip), GFP_KERNEL);
+
+	if (!rockchip)
+		return -ENOMEM;
+
+	count = of_clk_get_parent_count(np);
+	if (!count)
+		return -ENOENT;
+
+	rockchip->num_clocks = count;
+
+	rockchip->clks = devm_kcalloc(dev, rockchip->num_clocks,
+				      sizeof(struct clk *), GFP_KERNEL);
+	if (!rockchip->clks)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, rockchip);
+
+	rockchip->dev = dev;
+	rockchip->edev = NULL;
+
+	pm_runtime_set_active(dev);
+	pm_runtime_enable(dev);
+	ret = pm_runtime_get_sync(dev);
+	if (ret < 0) {
+		dev_err(dev, "get_sync failed with err %d\n", ret);
+		goto err1;
+	}
+
+	for (i = 0; i < rockchip->num_clocks; i++) {
+		struct clk	*clk;
+
+		clk = of_clk_get(np, i);
+		if (IS_ERR(clk)) {
+			while (--i >= 0)
+				clk_put(rockchip->clks[i]);
+			ret = PTR_ERR(clk);
+
+			goto err1;
+		}
+
+		ret = clk_prepare_enable(clk);
+		if (ret < 0) {
+			while (--i >= 0) {
+				clk_disable_unprepare(rockchip->clks[i]);
+				clk_put(rockchip->clks[i]);
+			}
+			clk_put(clk);
+
+			goto err1;
+		}
+
+		rockchip->clks[i] = clk;
+	}
+
+	rockchip->otg_rst = devm_reset_control_get(dev, "usb3-otg");
+	if (IS_ERR(rockchip->otg_rst)) {
+		dev_err(dev, "could not get reset controller\n");
+		ret = PTR_ERR(rockchip->otg_rst);
+		goto err2;
+	}
+
+	ret = dwc3_rockchip_extcon_register(rockchip);
+	if (ret < 0)
+		goto err2;
+
+	child = of_get_child_by_name(np, "dwc3");
+	if (!child) {
+		dev_err(dev, "failed to find dwc3 core node\n");
+		ret = -ENODEV;
+		goto err3;
+	}
+
+	/* Allocate and initialize the core */
+	ret = of_platform_populate(np, NULL, NULL, dev);
+	if (ret) {
+		dev_err(dev, "failed to create dwc3 core\n");
+		goto err3;
+	}
+
+	child_pdev = of_find_device_by_node(child);
+	if (!child_pdev) {
+		dev_err(dev, "failed to find dwc3 core device\n");
+		ret = -ENODEV;
+		goto err4;
+	}
+
+	rockchip->dwc = platform_get_drvdata(child_pdev);
+
+	if (rockchip->edev) {
+		pm_runtime_set_autosuspend_delay(&child_pdev->dev,
+						 DWC3_ROCKCHIP_AUTOSUSPEND_DELAY);
+		pm_runtime_allow(&child_pdev->dev);
+
+		if (rockchip->dwc->dr_mode == USB_DR_MODE_HOST ||
+		    rockchip->dwc->dr_mode == USB_DR_MODE_OTG) {
+			struct usb_hcd *hcd =
+				dev_get_drvdata(&rockchip->dwc->xhci->dev);
+
+			if (hcd->state != HC_STATE_HALT) {
+				usb_remove_hcd(hcd->shared_hcd);
+				usb_remove_hcd(hcd);
+			}
+		}
+	}
+
+	return ret;
+
+err4:
+	of_platform_depopulate(dev);
+
+err3:
+	dwc3_rockchip_extcon_unregister(rockchip);
+
+err2:
+	for (i = 0; i < rockchip->num_clocks; i++) {
+		clk_disable_unprepare(rockchip->clks[i]);
+		clk_put(rockchip->clks[i]);
+	}
+
+err1:
+	pm_runtime_put_sync(dev);
+	pm_runtime_disable(dev);
+
+	return ret;
+}
+
+static int dwc3_rockchip_remove(struct platform_device *pdev)
+{
+	struct dwc3_rockchip	*rockchip = platform_get_drvdata(pdev);
+	struct device		*dev = &pdev->dev;
+	int			i;
+
+	for (i = 0; i < rockchip->num_clocks; i++) {
+		clk_disable_unprepare(rockchip->clks[i]);
+		clk_put(rockchip->clks[i]);
+	}
+
+	dwc3_rockchip_extcon_unregister(rockchip);
+
+	of_platform_depopulate(dev);
+
+	pm_runtime_put_sync(dev);
+	pm_runtime_disable(dev);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int dwc3_rockchip_suspend(struct device *dev)
+{
+	struct dwc3_rockchip	*rockchip = dev_get_drvdata(dev);
+	int			i;
+
+	for (i = 0; i < rockchip->num_clocks; i++)
+		clk_disable(rockchip->clks[i]);
+
+	return 0;
+}
+
+static int dwc3_rockchip_resume(struct device *dev)
+{
+	struct dwc3_rockchip	*rockchip = dev_get_drvdata(dev);
+	int			i;
+
+	for (i = 0; i < rockchip->num_clocks; i++)
+		clk_enable(rockchip->clks[i]);
+
+	/* runtime set active to reflect active state. */
+	pm_runtime_disable(dev);
+	pm_runtime_set_active(dev);
+	pm_runtime_enable(dev);
+
+	return 0;
+}
+
+static const struct dev_pm_ops dwc3_rockchip_dev_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(dwc3_rockchip_suspend, dwc3_rockchip_resume)
+};
+
+#define DEV_PM_OPS	(&dwc3_rockchip_dev_pm_ops)
+#else
+#define DEV_PM_OPS	NULL
+#endif /* CONFIG_PM_SLEEP */
+
+static const struct of_device_id rockchip_dwc3_match[] = {
+	{ .compatible = "rockchip,rk3399-dwc3" },
+	{ /* Sentinel */ }
+};
+
+MODULE_DEVICE_TABLE(of, of_dwc3_rockchip_match);
+
+static struct platform_driver dwc3_rockchip_driver = {
+	.probe		= dwc3_rockchip_probe,
+	.remove		= dwc3_rockchip_remove,
+	.driver		= {
+		.name	= "rockchip-dwc3",
+		.of_match_table = rockchip_dwc3_match,
+		.pm	= DEV_PM_OPS,
+	},
+};
+
+module_platform_driver(dwc3_rockchip_driver);
+
+MODULE_ALIAS("platform:rockchip-dwc3");
+MODULE_AUTHOR("William Wu <william.wu@xxxxxxxxxxxxxx>");
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("DesignWare USB3 ROCKCHIP Glue Layer");
-- 
1.9.1