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, 543 insertions, 0 deletions

diff --git a/drivers/usb/cdns3/core.c b/drivers/usb/cdns3/core.c
new file mode 100644
index 000000000000..ddc73f1c87c5
--- /dev/null
+++ b/drivers/usb/cdns3/core.c
@@ -0,0 +1,543 @@
+// 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"
+#include "debug.h"
+
+/**
+ * cdns3_handshake - spin reading  until handshake completes or fails
+ * @ptr: address of device controller register to be read
+ * @mask: bits to look at in result of read
+ * @done: value of those bits when handshake succeeds
+ * @usec: timeout in microseconds
+ *
+ * Returns negative errno, or zero on success
+ *
+ * Success happens when the "mask" bits have the specified value (hardware
+ * handshake done). There are two failure modes: "usec" have passed (major
+ * hardware flakeout), or the register reads as all-ones (hardware removed).
+ */
+int cdns3_handshake(void __iomem *ptr, u32 mask, u32 done, int usec)
+{
+	u32 result;
+
+	do {
+		result = readl(ptr);
+		if (result == ~(u32)0)  /* card removed */
+			return -ENODEV;
+
+		result &= mask;
+		if (result == done)
+			return 0;
+
+		udelay(1);
+		usec--;
+	} while (usec > 0);
+
+	return -ETIMEDOUT;
+}
+
+static inline
+struct cdns3_role_driver *cdns3_get_current_role_driver(struct cdns3 *cdns)
+{
+	WARN_ON(cdns->role >= CDNS3_ROLE_END || !cdns->roles[cdns->role]);
+	return cdns->roles[cdns->role];
+}
+
+static int cdns3_role_start(struct cdns3 *cdns, enum cdns3_roles role)
+{
+	int ret;
+
+	if (WARN_ON(role >= CDNS3_ROLE_END))
+		return 0;
+
+	if (!cdns->roles[role])
+		return -ENXIO;
+
+	if (cdns->roles[role]->state == CDNS3_ROLE_STATE_ACTIVE)
+		return 0;
+
+	mutex_lock(&cdns->mutex);
+	cdns->role = role;
+	ret = cdns->roles[role]->start(cdns);
+	if (!ret)
+		cdns->roles[role]->state = CDNS3_ROLE_STATE_ACTIVE;
+	mutex_unlock(&cdns->mutex);
+	return ret;
+}
+
+void cdns3_role_stop(struct cdns3 *cdns)
+{
+	enum cdns3_roles role = cdns->role;
+
+	if (role >= CDNS3_ROLE_END) {
+		WARN_ON(role > CDNS3_ROLE_END);
+		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);
+}
+
+enum cdns3_roles cdsn3_get_real_role(struct cdns3 *cdns);
+
+static int cdns3_idle_role_start(struct cdns3 *cnds)
+{	/* Hold PHY in RESET */
+	return 0;
+}
+
+static void cdns3_idle_role_stop(struct cdns3 *cnds)
+{
+	/* Program Lane swap and bring PHY out of RESET */
+}
+
+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[CDNS3_ROLE_IDLE] = rdrv;
+
+	return 0;
+}
+
+/**
+ * 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 = CDNS3_ROLE_END;
+
+	/*
+	 * 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->desired_dr_mode = dr_mode;
+	cdns->dr_mode = dr_mode;
+
+	/*
+	 * desired_dr_mode might have changed so we need to update
+	 * the controller configuration"?
+	 */
+	ret = cdns3_drd_update_mode(cdns);
+	if (ret)
+		goto err;
+
+	cdns->role = cdsn3_get_real_role(cdns);
+
+	ret = cdns3_role_start(cdns, cdns->role);
+	if (ret) {
+		dev_err(dev, "can't start %s role\n",
+			cdns3_get_current_role_driver(cdns)->name);
+		goto err;
+	}
+
+	return ret;
+err:
+	cdns3_exit_roles(cdns);
+	return ret;
+}
+
+/**
+ * cdsn3_get_real_role - get real role of controller based on hardware settings.
+ * @cdns: Pointer to cdns3 structure
+ *
+ * Returns role
+ */
+enum cdns3_roles cdsn3_get_real_role(struct cdns3 *cdns)
+{
+	enum cdns3_roles role;
+	int id, vbus;
+
+	if (cdns->current_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 CDNS3_ROLE_IDLE: /* from IDLE, we can change to HOST or GADGET */
+		if (!id)
+			role = CDNS3_ROLE_HOST;
+		else if (vbus)
+			role = CDNS3_ROLE_GADGET;
+		break;
+	case CDNS3_ROLE_HOST: /* from HOST, we can only change to IDLE */
+		if (id)
+			role = CDNS3_ROLE_IDLE;
+		break;
+	case CDNS3_ROLE_GADGET: /* from GADGET, we can only change to IDLE */
+		if (!vbus)
+			role = CDNS3_ROLE_IDLE;
+		break;
+	case CDNS3_ROLE_END: /* only at initialization, move to IDLE */
+		role = CDNS3_ROLE_IDLE;
+		break;
+	}
+
+	dev_dbg(cdns->dev, "role %d -> %d\n", cdns->role, role);
+
+	return role;
+
+not_otg:
+	if (cdns3_is_host(cdns))
+		role = CDNS3_ROLE_HOST;
+	if (cdns3_is_device(cdns))
+		role = CDNS3_ROLE_GADGET;
+
+	return role;
+}
+
+/**
+ * cdns3_role_switch - work queue handler for role switch
+ *
+ * @work: work queue item structure
+ *
+ * Handles below events:
+ * - Role switch for dual-role devices
+ * - CDNS3_ROLE_GADGET <--> CDNS3_ROLE_END for peripheral-only devices
+ */
+static void cdns3_role_switch(struct work_struct *work)
+{
+	enum cdns3_roles role = CDNS3_ROLE_END;
+	struct cdns3_role_driver *role_drv;
+	enum cdns3_roles current_role;
+	struct cdns3 *cdns;
+	int ret = 0;
+
+	cdns = container_of(work, struct cdns3, role_switch_wq);
+
+	pm_runtime_get_sync(cdns->dev);
+
+	role = cdsn3_get_real_role(cdns);
+
+	role_drv = cdns3_get_current_role_driver(cdns);
+
+	/* Disable current role if requested from debugfs */
+	if (cdns->debug_disable && role_drv->state == CDNS3_ROLE_STATE_ACTIVE) {
+		cdns3_role_stop(cdns);
+		goto exit;
+	}
+
+	/* Do nothing if nothing changed */
+	if (cdns->role == role && role_drv->state == CDNS3_ROLE_STATE_ACTIVE)
+		goto exit;
+
+	cdns3_role_stop(cdns);
+
+	role = cdsn3_get_real_role(cdns);
+
+	current_role = cdns->role;
+	dev_dbg(cdns->dev, "Switching role");
+
+	ret = cdns3_role_start(cdns, role);
+	if (ret) {
+		/* Back to current role */
+		dev_err(cdns->dev, "set %d has failed, back to %d\n",
+			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);
+}
+
+/**
+ * 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);
+
+	phy_init(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);
+
+	phy_init(cdns->usb3_phy);
+	ret = phy_init(cdns->usb3_phy);
+	if (ret)
+		return ret;
+
+	ret = phy_power_on(cdns->usb2_phy);
+	if (ret)
+		return ret;
+
+	ret = phy_power_on(cdns->usb3_phy);
+	if (ret)
+		goto err1;
+
+	INIT_WORK(&cdns->role_switch_wq, cdns3_role_switch);
+
+	ret = cdns3_drd_init(cdns);
+	if (ret)
+		goto err2;
+
+	ret = cdns3_core_init_role(cdns);
+	if (ret)
+		goto err2;
+
+	cdns3_debugfs_init(cdns);
+	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;
+
+err2:
+	phy_power_off(cdns->usb3_phy);
+
+err1:
+	phy_power_off(cdns->usb2_phy);
+	phy_exit(cdns->usb2_phy);
+	phy_exit(cdns->usb3_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_debugfs_exit(cdns);
+	cdns3_exit_roles(cdns);
+	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_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),
+	},
+};
+
+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");