usb: Add Cadence USB3 host and gadget driver

Add support for USB3 host and gadget driver. This is a direct sync of
Linux kernel Cadence USB stack that from v5.4-rc1 release.
Driver has been modified so that it compiles without errors against
U-Boot code base.
Features not required for U-Boot such as scatter-gather DMA and OTG
interrupt handling has been dropped.

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
[jjhiblot@ti.com: Add PHY support]
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
diff --git a/drivers/usb/cdns3/core.c b/drivers/usb/cdns3/core.c
new file mode 100644
index 0000000..f1e4bb6
--- /dev/null
+++ b/drivers/usb/cdns3/core.c
@@ -0,0 +1,498 @@
+// 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 <common.h>
+#include <dm.h>
+#include <dm/device-internal.h>
+#include <dm/lists.h>
+#include <linux/kernel.h>
+#include <linux/io.h>
+#include <usb.h>
+#include "../host/xhci.h"
+
+#include "core.h"
+#include "host-export.h"
+#include "gadget-export.h"
+#include "drd.h"
+
+static int cdns3_idle_init(struct cdns3 *cdns);
+
+struct cdns3_host_priv {
+	struct xhci_ctrl xhci_ctrl;
+	struct cdns3 cdns;
+};
+
+struct cdns3_gadget_priv {
+	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 udevice *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_of_offset(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 defined(CONFIG_SPL_USB_HOST_SUPPORT) || !defined(CONFIG_SPL_BUILD)
+	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;
+		}
+	}
+#endif
+
+#if CONFIG_IS_ENABLED(DM_USB_GADGET)
+	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;
+		}
+	}
+#endif
+
+	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 */
+	generic_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;
+
+	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:
+	return ret;
+}
+
+static int cdns3_probe(struct cdns3 *cdns)
+{
+	struct udevice *dev = cdns->dev;
+	int ret;
+
+	cdns->xhci_regs = dev_remap_addr_name(dev, "xhci");
+	if (!cdns->xhci_regs)
+		return -EINVAL;
+
+	cdns->dev_regs = dev_remap_addr_name(dev, "dev");
+	if (!cdns->dev_regs)
+		return -EINVAL;
+
+	mutex_init(&cdns->mutex);
+
+	ret = generic_phy_get_by_name(dev, "cdns3,usb2-phy", &cdns->usb2_phy);
+	if (ret)
+		dev_warn(dev, "Unable to get USB2 phy (ret %d)\n", ret);
+
+	ret = generic_phy_init(&cdns->usb2_phy);
+	if (ret)
+		return ret;
+
+	ret = generic_phy_get_by_name(dev, "cdns3,usb3-phy", &cdns->usb3_phy);
+	if (ret)
+		dev_warn(dev, "Unable to get USB3 phy (ret %d)\n", ret);
+
+	ret = generic_phy_init(&cdns->usb3_phy);
+	if (ret)
+		return ret;
+
+	ret = generic_phy_power_on(&cdns->usb2_phy);
+	if (ret)
+		return ret;
+
+	ret = generic_phy_power_on(&cdns->usb3_phy);
+	if (ret)
+		return ret;
+
+	ret = cdns3_drd_init(cdns);
+	if (ret)
+		return ret;
+
+	ret = cdns3_core_init_role(cdns);
+	if (ret)
+		return ret;
+
+	dev_dbg(dev, "Cadence USB3 core: probe succeed\n");
+
+	return 0;
+}
+
+static int cdns3_remove(struct cdns3 *cdns)
+{
+	cdns3_exit_roles(cdns);
+	generic_phy_power_off(&cdns->usb2_phy);
+	generic_phy_power_off(&cdns->usb3_phy);
+	generic_phy_exit(&cdns->usb2_phy);
+	generic_phy_exit(&cdns->usb3_phy);
+	return 0;
+}
+
+static const struct udevice_id cdns3_ids[] = {
+	{ .compatible = "cdns,usb3" },
+	{ },
+};
+
+int cdns3_bind(struct udevice *parent)
+{
+	int from = dev_of_offset(parent);
+	const void *fdt = gd->fdt_blob;
+	enum usb_dr_mode dr_mode;
+	struct udevice *dev;
+	const char *driver;
+	const char *name;
+	int node;
+	int ret;
+
+	node = fdt_node_offset_by_compatible(fdt, from, "cdns,usb3");
+	if (node < 0) {
+		ret = -ENODEV;
+		goto fail;
+	}
+
+	name = fdt_get_name(fdt, node, NULL);
+	dr_mode = usb_get_dr_mode(node);
+
+	switch (dr_mode) {
+#if defined(CONFIG_SPL_USB_HOST_SUPPORT) || \
+	(!defined(CONFIG_SPL_BUILD) && defined(CONFIG_USB_HOST))
+	case USB_DR_MODE_HOST:
+		debug("%s: dr_mode: HOST\n", __func__);
+		driver = "cdns-usb3-host";
+		break;
+#endif
+#if CONFIG_IS_ENABLED(DM_USB_GADGET)
+	case USB_DR_MODE_PERIPHERAL:
+		debug("%s: dr_mode: PERIPHERAL\n", __func__);
+		driver = "cdns-usb3-peripheral";
+		break;
+#endif
+	default:
+		printf("%s: unsupported dr_mode\n", __func__);
+		ret = -ENODEV;
+		goto fail;
+	};
+
+	ret = device_bind_driver_to_node(parent, driver, name,
+					 offset_to_ofnode(node), &dev);
+	if (ret) {
+		printf("%s: not able to bind usb device mode\n",
+		       __func__);
+		goto fail;
+	}
+
+	return 0;
+
+fail:
+	/* do not return an error: failing to bind would hang the board */
+	return 0;
+}
+
+#if CONFIG_IS_ENABLED(DM_USB_GADGET)
+static int cdns3_gadget_probe(struct udevice *dev)
+{
+	struct cdns3_gadget_priv *priv = dev_get_priv(dev);
+	struct cdns3 *cdns = &priv->cdns;
+
+	cdns->dev = dev;
+
+	return cdns3_probe(cdns);
+}
+
+static int cdns3_gadget_remove(struct udevice *dev)
+{
+	struct cdns3_gadget_priv *priv = dev_get_priv(dev);
+	struct cdns3 *cdns = &priv->cdns;
+
+	return cdns3_remove(cdns);
+}
+
+U_BOOT_DRIVER(cdns_usb3_peripheral) = {
+	.name	= "cdns-usb3-peripheral",
+	.id	= UCLASS_USB_GADGET_GENERIC,
+	.of_match = cdns3_ids,
+	.probe = cdns3_gadget_probe,
+	.remove = cdns3_gadget_remove,
+	.priv_auto_alloc_size = sizeof(struct cdns3_gadget_priv),
+	.flags = DM_FLAG_ALLOC_PRIV_DMA,
+};
+#endif
+
+#if defined(CONFIG_SPL_USB_HOST_SUPPORT) || \
+	(!defined(CONFIG_SPL_BUILD) && defined(CONFIG_USB_HOST))
+static int cdns3_host_probe(struct udevice *dev)
+{
+	struct cdns3_host_priv *priv = dev_get_priv(dev);
+	struct cdns3 *cdns = &priv->cdns;
+
+	cdns->dev = dev;
+
+	return cdns3_probe(cdns);
+}
+
+static int cdns3_host_remove(struct udevice *dev)
+{
+	struct cdns3_host_priv *priv = dev_get_priv(dev);
+	struct cdns3 *cdns = &priv->cdns;
+
+	return cdns3_remove(cdns);
+}
+
+U_BOOT_DRIVER(cdns_usb3_host) = {
+	.name	= "cdns-usb3-host",
+	.id	= UCLASS_USB,
+	.of_match = cdns3_ids,
+	.probe = cdns3_host_probe,
+	.remove = cdns3_host_remove,
+	.priv_auto_alloc_size = sizeof(struct cdns3_host_priv),
+	.ops = &xhci_usb_ops,
+	.flags = DM_FLAG_ALLOC_PRIV_DMA,
+};
+#endif