usb: cdns3: Add Cadence USB3 DRD Driver

This patch introduce new Cadence USBSS DRD driver to Linux kernel.

The Cadence USBSS DRD Controller is a highly configurable IP Core which
can be instantiated as Dual-Role Device (DRD), Peripheral Only and
Host Only (XHCI)configurations.

The current driver has been validated with FPGA platform. We have
support for PCIe bus, which is used on FPGA prototyping.

The host side of USBSS-DRD controller is compliant with XHCI
specification, so it works with standard XHCI Linux driver.

Signed-off-by: Pawel Laszczak <pawell@cadence.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

1 files changed, 653 insertions, 0 deletions

diff --git a/drivers/usb/cdns3/core.c b/drivers/usb/cdns3/core.c
new file mode 100644
index 000000000000..300df58a190b
--- /dev/null
+++ b/drivers/usb/cdns3/core.c
@@ -0,0 +1,653 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Cadence USBSS DRD Driver.
+ *
+ * Copyright (C) 2018-2019 Cadence.
+ * Copyright (C) 2017-2018 NXP
+ * Copyright (C) 2019 Texas Instruments
+ *
+ * Author: Peter Chen <peter.chen@nxp.com>
+ *         Pawel Laszczak <pawell@cadence.com>
+ *         Roger Quadros <rogerq@ti.com>
+ */
+
+#include <linux/dma-mapping.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/pm_runtime.h>
+
+#include "gadget.h"
+#include "core.h"
+#include "host-export.h"
+#include "gadget-export.h"
+#include "drd.h"
+
+static int cdns3_idle_init(struct cdns3 *cdns);
+
+static inline
+struct cdns3_role_driver *cdns3_get_current_role_driver(struct cdns3 *cdns)
+{
+	WARN_ON(!cdns->roles[cdns->role]);
+	return cdns->roles[cdns->role];
+}
+
+static int cdns3_role_start(struct cdns3 *cdns, enum usb_role role)
+{
+	int ret;
+
+	if (WARN_ON(role > USB_ROLE_DEVICE))
+		return 0;
+
+	mutex_lock(&cdns->mutex);
+	cdns->role = role;
+	mutex_unlock(&cdns->mutex);
+
+	if (!cdns->roles[role])
+		return -ENXIO;
+
+	if (cdns->roles[role]->state == CDNS3_ROLE_STATE_ACTIVE)
+		return 0;
+
+	mutex_lock(&cdns->mutex);
+	ret = cdns->roles[role]->start(cdns);
+	if (!ret)
+		cdns->roles[role]->state = CDNS3_ROLE_STATE_ACTIVE;
+	mutex_unlock(&cdns->mutex);
+
+	return ret;
+}
+
+static void cdns3_role_stop(struct cdns3 *cdns)
+{
+	enum usb_role role = cdns->role;
+
+	if (WARN_ON(role > USB_ROLE_DEVICE))
+		return;
+
+	if (cdns->roles[role]->state == CDNS3_ROLE_STATE_INACTIVE)
+		return;
+
+	mutex_lock(&cdns->mutex);
+	cdns->roles[role]->stop(cdns);
+	cdns->roles[role]->state = CDNS3_ROLE_STATE_INACTIVE;
+	mutex_unlock(&cdns->mutex);
+}
+
+static void cdns3_exit_roles(struct cdns3 *cdns)
+{
+	cdns3_role_stop(cdns);
+	cdns3_drd_exit(cdns);
+}
+
+static enum usb_role cdsn3_hw_role_state_machine(struct cdns3 *cdns);
+
+/**
+ * cdns3_core_init_role - initialize role of operation
+ * @cdns: Pointer to cdns3 structure
+ *
+ * Returns 0 on success otherwise negative errno
+ */
+static int cdns3_core_init_role(struct cdns3 *cdns)
+{
+	struct device *dev = cdns->dev;
+	enum usb_dr_mode best_dr_mode;
+	enum usb_dr_mode dr_mode;
+	int ret = 0;
+
+	dr_mode = usb_get_dr_mode(dev);
+	cdns->role = USB_ROLE_NONE;
+
+	/*
+	 * If driver can't read mode by means of usb_get_dr_mode function then
+	 * chooses mode according with Kernel configuration. This setting
+	 * can be restricted later depending on strap pin configuration.
+	 */
+	if (dr_mode == USB_DR_MODE_UNKNOWN) {
+		if (IS_ENABLED(CONFIG_USB_CDNS3_HOST) &&
+		    IS_ENABLED(CONFIG_USB_CDNS3_GADGET))
+			dr_mode = USB_DR_MODE_OTG;
+		else if (IS_ENABLED(CONFIG_USB_CDNS3_HOST))
+			dr_mode = USB_DR_MODE_HOST;
+		else if (IS_ENABLED(CONFIG_USB_CDNS3_GADGET))
+			dr_mode = USB_DR_MODE_PERIPHERAL;
+	}
+
+	/*
+	 * At this point cdns->dr_mode contains strap configuration.
+	 * Driver try update this setting considering kernel configuration
+	 */
+	best_dr_mode = cdns->dr_mode;
+
+	ret = cdns3_idle_init(cdns);
+	if (ret)
+		return ret;
+
+	if (dr_mode == USB_DR_MODE_OTG) {
+		best_dr_mode = cdns->dr_mode;
+	} else if (cdns->dr_mode == USB_DR_MODE_OTG) {
+		best_dr_mode = dr_mode;
+	} else if (cdns->dr_mode != dr_mode) {
+		dev_err(dev, "Incorrect DRD configuration\n");
+		return -EINVAL;
+	}
+
+	dr_mode = best_dr_mode;
+
+	if (dr_mode == USB_DR_MODE_OTG || dr_mode == USB_DR_MODE_HOST) {
+		ret = cdns3_host_init(cdns);
+		if (ret) {
+			dev_err(dev, "Host initialization failed with %d\n",
+				ret);
+			goto err;
+		}
+	}
+
+	if (dr_mode == USB_DR_MODE_OTG || dr_mode == USB_DR_MODE_PERIPHERAL) {
+		ret = cdns3_gadget_init(cdns);
+		if (ret) {
+			dev_err(dev, "Device initialization failed with %d\n",
+				ret);
+			goto err;
+		}
+	}
+
+	cdns->dr_mode = dr_mode;
+
+	ret = cdns3_drd_update_mode(cdns);
+	if (ret)
+		goto err;
+
+	if (cdns->dr_mode != USB_DR_MODE_OTG) {
+		ret = cdns3_hw_role_switch(cdns);
+		if (ret)
+			goto err;
+	}
+
+	return ret;
+err:
+	cdns3_exit_roles(cdns);
+	return ret;
+}
+
+/**
+ * cdsn3_hw_role_state_machine  - role switch state machine based on hw events.
+ * @cdns: Pointer to controller structure.
+ *
+ * Returns next role to be entered based on hw events.
+ */
+static enum usb_role cdsn3_hw_role_state_machine(struct cdns3 *cdns)
+{
+	enum usb_role role;
+	int id, vbus;
+
+	if (cdns->dr_mode != USB_DR_MODE_OTG)
+		goto not_otg;
+
+	id = cdns3_get_id(cdns);
+	vbus = cdns3_get_vbus(cdns);
+
+	/*
+	 * Role change state machine
+	 * Inputs: ID, VBUS
+	 * Previous state: cdns->role
+	 * Next state: role
+	 */
+	role = cdns->role;
+
+	switch (role) {
+	case USB_ROLE_NONE:
+		/*
+		 * Driver treats USB_ROLE_NONE synonymous to IDLE state from
+		 * controller specification.
+		 */
+		if (!id)
+			role = USB_ROLE_HOST;
+		else if (vbus)
+			role = USB_ROLE_DEVICE;
+		break;
+	case USB_ROLE_HOST: /* from HOST, we can only change to NONE */
+		if (id)
+			role = USB_ROLE_NONE;
+		break;
+	case USB_ROLE_DEVICE: /* from GADGET, we can only change to NONE*/
+		if (!vbus)
+			role = USB_ROLE_NONE;
+		break;
+	}
+
+	dev_dbg(cdns->dev, "role %d -> %d\n", cdns->role, role);
+
+	return role;
+
+not_otg:
+	if (cdns3_is_host(cdns))
+		role = USB_ROLE_HOST;
+	if (cdns3_is_device(cdns))
+		role = USB_ROLE_DEVICE;
+
+	return role;
+}
+
+static int cdns3_idle_role_start(struct cdns3 *cdns)
+{
+	return 0;
+}
+
+static void cdns3_idle_role_stop(struct cdns3 *cdns)
+{
+	/* Program Lane swap and bring PHY out of RESET */
+	phy_reset(cdns->usb3_phy);
+}
+
+static int cdns3_idle_init(struct cdns3 *cdns)
+{
+	struct cdns3_role_driver *rdrv;
+
+	rdrv = devm_kzalloc(cdns->dev, sizeof(*rdrv), GFP_KERNEL);
+	if (!rdrv)
+		return -ENOMEM;
+
+	rdrv->start = cdns3_idle_role_start;
+	rdrv->stop = cdns3_idle_role_stop;
+	rdrv->state = CDNS3_ROLE_STATE_INACTIVE;
+	rdrv->suspend = NULL;
+	rdrv->resume = NULL;
+	rdrv->name = "idle";
+
+	cdns->roles[USB_ROLE_NONE] = rdrv;
+
+	return 0;
+}
+
+/**
+ * cdns3_hw_role_switch - switch roles based on HW state
+ * @cdns3: controller
+ */
+int cdns3_hw_role_switch(struct cdns3 *cdns)
+{
+	enum usb_role real_role, current_role;
+	int ret = 0;
+
+	/* Do nothing if role based on syfs. */
+	if (cdns->role_override)
+		return 0;
+
+	pm_runtime_get_sync(cdns->dev);
+
+	current_role = cdns->role;
+	real_role = cdsn3_hw_role_state_machine(cdns);
+
+	/* Do nothing if nothing changed */
+	if (current_role == real_role)
+		goto exit;
+
+	cdns3_role_stop(cdns);
+
+	dev_dbg(cdns->dev, "Switching role %d -> %d", current_role, real_role);
+
+	ret = cdns3_role_start(cdns, real_role);
+	if (ret) {
+		/* Back to current role */
+		dev_err(cdns->dev, "set %d has failed, back to %d\n",
+			real_role, current_role);
+		ret = cdns3_role_start(cdns, current_role);
+		if (ret)
+			dev_err(cdns->dev, "back to %d failed too\n",
+				current_role);
+	}
+exit:
+	pm_runtime_put_sync(cdns->dev);
+	return ret;
+}
+
+/**
+ * cdsn3_role_get - get current role of controller.
+ *
+ * @dev: Pointer to device structure
+ *
+ * Returns role
+ */
+static enum usb_role cdns3_role_get(struct device *dev)
+{
+	struct cdns3 *cdns = dev_get_drvdata(dev);
+
+	return cdns->role;
+}
+
+/**
+ * cdns3_role_set - set current role of controller.
+ *
+ * @dev: pointer to device object
+ * @role - the previous role
+ * Handles below events:
+ * - Role switch for dual-role devices
+ * - USB_ROLE_GADGET <--> USB_ROLE_NONE for peripheral-only devices
+ */
+static int cdns3_role_set(struct device *dev, enum usb_role role)
+{
+	struct cdns3 *cdns = dev_get_drvdata(dev);
+	int ret = 0;
+
+	pm_runtime_get_sync(cdns->dev);
+
+	/*
+	 * FIXME: switch role framework should be extended to meet
+	 * requirements. Driver assumes that role can be controlled
+	 * by SW or HW. Temporary workaround is to use USB_ROLE_NONE to
+	 * switch from SW to HW control.
+	 *
+	 * For dr_mode == USB_DR_MODE_OTG:
+	 *	if user sets USB_ROLE_HOST or USB_ROLE_DEVICE then driver
+	 *	sets role_override flag and forces that role.
+	 *	if user sets USB_ROLE_NONE, driver clears role_override and lets
+	 *	HW state machine take over.
+	 *
+	 * For dr_mode != USB_DR_MODE_OTG:
+	 *	Assumptions:
+	 *	1. Restricted user control between NONE and dr_mode.
+	 *	2. Driver doesn't need to rely on role_override flag.
+	 *	3. Driver needs to ensure that HW state machine is never called
+	 *	   if dr_mode != USB_DR_MODE_OTG.
+	 */
+	if (role == USB_ROLE_NONE)
+		cdns->role_override = 0;
+	else
+		cdns->role_override = 1;
+
+	/*
+	 * HW state might have changed so driver need to trigger
+	 * HW state machine if dr_mode == USB_DR_MODE_OTG.
+	 */
+	if (!cdns->role_override && cdns->dr_mode == USB_DR_MODE_OTG) {
+		cdns3_hw_role_switch(cdns);
+		goto pm_put;
+	}
+
+	if (cdns->role == role)
+		goto pm_put;
+
+	if (cdns->dr_mode == USB_DR_MODE_HOST) {
+		switch (role) {
+		case USB_ROLE_NONE:
+		case USB_ROLE_HOST:
+			break;
+		default:
+			ret = -EPERM;
+			goto pm_put;
+		}
+	}
+
+	if (cdns->dr_mode == USB_DR_MODE_PERIPHERAL) {
+		switch (role) {
+		case USB_ROLE_NONE:
+		case USB_ROLE_DEVICE:
+			break;
+		default:
+			ret = -EPERM;
+			goto pm_put;
+		}
+	}
+
+	cdns3_role_stop(cdns);
+	ret = cdns3_role_start(cdns, role);
+	if (ret) {
+		dev_err(cdns->dev, "set role %d has failed\n", role);
+		ret = -EPERM;
+	}
+
+pm_put:
+	pm_runtime_put_sync(cdns->dev);
+	return ret;
+}
+
+static const struct usb_role_switch_desc cdns3_switch_desc = {
+	.set = cdns3_role_set,
+	.get = cdns3_role_get,
+	.allow_userspace_control = true,
+};
+
+/**
+ * cdns3_probe - probe for cdns3 core device
+ * @pdev: Pointer to cdns3 core platform device
+ *
+ * Returns 0 on success otherwise negative errno
+ */
+static int cdns3_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct resource	*res;
+	struct cdns3 *cdns;
+	void __iomem *regs;
+	int ret;
+
+	ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32));
+	if (ret) {
+		dev_err(dev, "error setting dma mask: %d\n", ret);
+		return -ENODEV;
+	}
+
+	cdns = devm_kzalloc(dev, sizeof(*cdns), GFP_KERNEL);
+	if (!cdns)
+		return -ENOMEM;
+
+	cdns->dev = dev;
+
+	platform_set_drvdata(pdev, cdns);
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_IRQ, "host");
+	if (!res) {
+		dev_err(dev, "missing host IRQ\n");
+		return -ENODEV;
+	}
+
+	cdns->xhci_res[0] = *res;
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "xhci");
+	if (!res) {
+		dev_err(dev, "couldn't get xhci resource\n");
+		return -ENXIO;
+	}
+
+	cdns->xhci_res[1] = *res;
+
+	cdns->dev_irq = platform_get_irq_byname(pdev, "peripheral");
+	if (cdns->dev_irq == -EPROBE_DEFER)
+		return cdns->dev_irq;
+
+	if (cdns->dev_irq < 0)
+		dev_err(dev, "couldn't get peripheral irq\n");
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dev");
+	regs = devm_ioremap_resource(dev, res);
+	if (IS_ERR(regs)) {
+		dev_err(dev, "couldn't iomap dev resource\n");
+		return PTR_ERR(regs);
+	}
+	cdns->dev_regs	= regs;
+
+	cdns->otg_irq = platform_get_irq_byname(pdev, "otg");
+	if (cdns->otg_irq == -EPROBE_DEFER)
+		return cdns->otg_irq;
+
+	if (cdns->otg_irq < 0) {
+		dev_err(dev, "couldn't get otg irq\n");
+		return cdns->otg_irq;
+	}
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "otg");
+	if (!res) {
+		dev_err(dev, "couldn't get otg resource\n");
+		return -ENXIO;
+	}
+
+	cdns->otg_res = *res;
+
+	mutex_init(&cdns->mutex);
+
+	cdns->usb2_phy = devm_phy_optional_get(dev, "cdns3,usb2-phy");
+	if (IS_ERR(cdns->usb2_phy))
+		return PTR_ERR(cdns->usb2_phy);
+
+	ret = phy_init(cdns->usb2_phy);
+	if (ret)
+		return ret;
+
+	cdns->usb3_phy = devm_phy_optional_get(dev, "cdns3,usb3-phy");
+	if (IS_ERR(cdns->usb3_phy))
+		return PTR_ERR(cdns->usb3_phy);
+
+	ret = phy_init(cdns->usb3_phy);
+	if (ret)
+		goto err1;
+
+	ret = phy_power_on(cdns->usb2_phy);
+	if (ret)
+		goto err2;
+
+	ret = phy_power_on(cdns->usb3_phy);
+	if (ret)
+		goto err3;
+
+	cdns->role_sw = usb_role_switch_register(dev, &cdns3_switch_desc);
+	if (IS_ERR(cdns->role_sw)) {
+		ret = PTR_ERR(cdns->role_sw);
+		dev_warn(dev, "Unable to register Role Switch\n");
+		goto err4;
+	}
+
+	ret = cdns3_drd_init(cdns);
+	if (ret)
+		goto err5;
+
+	ret = cdns3_core_init_role(cdns);
+	if (ret)
+		goto err5;
+
+	device_set_wakeup_capable(dev, true);
+	pm_runtime_set_active(dev);
+	pm_runtime_enable(dev);
+
+	/*
+	 * The controller needs less time between bus and controller suspend,
+	 * and we also needs a small delay to avoid frequently entering low
+	 * power mode.
+	 */
+	pm_runtime_set_autosuspend_delay(dev, 20);
+	pm_runtime_mark_last_busy(dev);
+	pm_runtime_use_autosuspend(dev);
+	dev_dbg(dev, "Cadence USB3 core: probe succeed\n");
+
+	return 0;
+err5:
+	cdns3_drd_exit(cdns);
+	usb_role_switch_unregister(cdns->role_sw);
+err4:
+	phy_power_off(cdns->usb3_phy);
+
+err3:
+	phy_power_off(cdns->usb2_phy);
+err2:
+	phy_exit(cdns->usb3_phy);
+err1:
+	phy_exit(cdns->usb2_phy);
+
+	return ret;
+}
+
+/**
+ * cdns3_remove - unbind drd driver and clean up
+ * @pdev: Pointer to Linux platform device
+ *
+ * Returns 0 on success otherwise negative errno
+ */
+static int cdns3_remove(struct platform_device *pdev)
+{
+	struct cdns3 *cdns = platform_get_drvdata(pdev);
+
+	pm_runtime_get_sync(&pdev->dev);
+	pm_runtime_disable(&pdev->dev);
+	pm_runtime_put_noidle(&pdev->dev);
+	cdns3_exit_roles(cdns);
+	usb_role_switch_unregister(cdns->role_sw);
+	phy_power_off(cdns->usb2_phy);
+	phy_power_off(cdns->usb3_phy);
+	phy_exit(cdns->usb2_phy);
+	phy_exit(cdns->usb3_phy);
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+
+static int cdns3_suspend(struct device *dev)
+{
+	struct cdns3 *cdns = dev_get_drvdata(dev);
+	unsigned long flags;
+
+	if (cdns->role == USB_ROLE_HOST)
+		return 0;
+
+	if (pm_runtime_status_suspended(dev))
+		pm_runtime_resume(dev);
+
+	if (cdns->roles[cdns->role]->suspend) {
+		spin_lock_irqsave(&cdns->gadget_dev->lock, flags);
+		cdns->roles[cdns->role]->suspend(cdns, false);
+		spin_unlock_irqrestore(&cdns->gadget_dev->lock, flags);
+	}
+
+	return 0;
+}
+
+static int cdns3_resume(struct device *dev)
+{
+	struct cdns3 *cdns = dev_get_drvdata(dev);
+	unsigned long flags;
+
+	if (cdns->role == USB_ROLE_HOST)
+		return 0;
+
+	if (cdns->roles[cdns->role]->resume) {
+		spin_lock_irqsave(&cdns->gadget_dev->lock, flags);
+		cdns->roles[cdns->role]->resume(cdns, false);
+		spin_unlock_irqrestore(&cdns->gadget_dev->lock, flags);
+	}
+
+	pm_runtime_disable(dev);
+	pm_runtime_set_active(dev);
+	pm_runtime_enable(dev);
+
+	return 0;
+}
+#endif
+
+static const struct dev_pm_ops cdns3_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(cdns3_suspend, cdns3_resume)
+};
+
+#ifdef CONFIG_OF
+static const struct of_device_id of_cdns3_match[] = {
+	{ .compatible = "cdns,usb3" },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, of_cdns3_match);
+#endif
+
+static struct platform_driver cdns3_driver = {
+	.probe		= cdns3_probe,
+	.remove		= cdns3_remove,
+	.driver		= {
+		.name	= "cdns-usb3",
+		.of_match_table	= of_match_ptr(of_cdns3_match),
+		.pm	= &cdns3_pm_ops,
+	},
+};
+
+module_platform_driver(cdns3_driver);
+
+MODULE_ALIAS("platform:cdns3");
+MODULE_AUTHOR("Pawel Laszczak <pawell@cadence.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Cadence USB3 DRD Controller Driver");