USB: xHCI: Add stack support for xHCI

This adds stack layer for eXtensible Host Controller Interface
which facilitates use of USB 3.0 in host mode.

Adapting xHCI host controller driver in linux-kernel
by Sarah Sharp to needs in u-boot.

Initial porting from Linux kernel version 3.4, with following
top commit history of drivers/usb/host/xhci* :
cf84055 xHCI: Cleanup isoc transfer ring when TD length mismatch found

This adds the basic xHCI host controller driver with bare minimum
features:
- Control/Bulk transfer support has been added with required
  infrastructure for necessary xHC data structures.
- Stream protocol hasn't been supported yet.
- No support for quirky devices has been added.

Signed-off-by: Vikas C Sajjan <vikas.sajjan@samsung.com>
Signed-off-by: Julius Werner <jwerner@chromium.org>
Signed-off-by: Vivek Gautam <gautam.vivek@samsung.com>
Cc: Simon Glass <sjg@chromium.org>
Cc: Minkyu Kang <mk7.kang@samsung.com>
Cc: Dan Murphy <dmurphy@ti.com>
Cc: Marek Vasut <marex@denx.de>

1 files changed, 1030 insertions, 0 deletions

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
new file mode 100644
index 0000000..57fa4ff
--- /dev/null
+++ b/drivers/usb/host/xhci.c
@@ -0,0 +1,1030 @@
+/*
+ * USB HOST XHCI Controller stack
+ *
+ * Based on xHCI host controller driver in linux-kernel
+ * by Sarah Sharp.
+ *
+ * Copyright (C) 2008 Intel Corp.
+ * Author: Sarah Sharp
+ *
+ * Copyright (C) 2013 Samsung Electronics Co.Ltd
+ * Authors: Vivek Gautam <gautam.vivek@samsung.com>
+ *	    Vikas Sajjan <vikas.sajjan@samsung.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+/**
+ * This file gives the xhci stack for usb3.0 looking into
+ * xhci specification Rev1.0 (5/21/10).
+ * The quirk devices support hasn't been given yet.
+ */
+
+#include <common.h>
+#include <asm/byteorder.h>
+#include <usb.h>
+#include <malloc.h>
+#include <watchdog.h>
+#include <asm/cache.h>
+#include <asm/unaligned.h>
+#include <asm-generic/errno.h>
+#include "xhci.h"
+
+#ifndef CONFIG_USB_MAX_CONTROLLER_COUNT
+#define CONFIG_USB_MAX_CONTROLLER_COUNT 1
+#endif
+
+static struct descriptor {
+	struct usb_hub_descriptor hub;
+	struct usb_device_descriptor device;
+	struct usb_config_descriptor config;
+	struct usb_interface_descriptor interface;
+	struct usb_endpoint_descriptor endpoint;
+	struct usb_ss_ep_comp_descriptor ep_companion;
+} __attribute__ ((packed)) descriptor = {
+	{
+		0xc,		/* bDescLength */
+		0x2a,		/* bDescriptorType: hub descriptor */
+		2,		/* bNrPorts -- runtime modified */
+		cpu_to_le16(0x8), /* wHubCharacteristics */
+		10,		/* bPwrOn2PwrGood */
+		0,		/* bHubCntrCurrent */
+		{},		/* Device removable */
+		{}		/* at most 7 ports! XXX */
+	},
+	{
+		0x12,		/* bLength */
+		1,		/* bDescriptorType: UDESC_DEVICE */
+		cpu_to_le16(0x0300), /* bcdUSB: v3.0 */
+		9,		/* bDeviceClass: UDCLASS_HUB */
+		0,		/* bDeviceSubClass: UDSUBCLASS_HUB */
+		3,		/* bDeviceProtocol: UDPROTO_SSHUBSTT */
+		9,		/* bMaxPacketSize: 512 bytes  2^9 */
+		0x0000,		/* idVendor */
+		0x0000,		/* idProduct */
+		cpu_to_le16(0x0100), /* bcdDevice */
+		1,		/* iManufacturer */
+		2,		/* iProduct */
+		0,		/* iSerialNumber */
+		1		/* bNumConfigurations: 1 */
+	},
+	{
+		0x9,
+		2,		/* bDescriptorType: UDESC_CONFIG */
+		cpu_to_le16(0x1f), /* includes SS endpoint descriptor */
+		1,		/* bNumInterface */
+		1,		/* bConfigurationValue */
+		0,		/* iConfiguration */
+		0x40,		/* bmAttributes: UC_SELF_POWER */
+		0		/* bMaxPower */
+	},
+	{
+		0x9,		/* bLength */
+		4,		/* bDescriptorType: UDESC_INTERFACE */
+		0,		/* bInterfaceNumber */
+		0,		/* bAlternateSetting */
+		1,		/* bNumEndpoints */
+		9,		/* bInterfaceClass: UICLASS_HUB */
+		0,		/* bInterfaceSubClass: UISUBCLASS_HUB */
+		0,		/* bInterfaceProtocol: UIPROTO_HSHUBSTT */
+		0		/* iInterface */
+	},
+	{
+		0x7,		/* bLength */
+		5,		/* bDescriptorType: UDESC_ENDPOINT */
+		0x81,		/* bEndpointAddress: IN endpoint 1 */
+		3,		/* bmAttributes: UE_INTERRUPT */
+		8,		/* wMaxPacketSize */
+		255		/* bInterval */
+	},
+	{
+		0x06,		/* ss_bLength */
+		0x30,		/* ss_bDescriptorType: SS EP Companion */
+		0x00,		/* ss_bMaxBurst: allows 1 TX between ACKs */
+		/* ss_bmAttributes: 1 packet per service interval */
+		0x00,
+		/* ss_wBytesPerInterval: 15 bits for max 15 ports */
+		cpu_to_le16(0x02),
+	},
+};
+
+static struct xhci_ctrl xhcic[CONFIG_USB_MAX_CONTROLLER_COUNT];
+
+/**
+ * Waits for as per specified amount of time
+ * for the "result" to match with "done"
+ *
+ * @param ptr	pointer to the register to be read
+ * @param mask	mask for the value read
+ * @param done	value to be campared with result
+ * @param usec	time to wait till
+ * @return 0 if handshake is success else < 0 on failure
+ */
+static int handshake(uint32_t volatile *ptr, uint32_t mask,
+					uint32_t done, int usec)
+{
+	uint32_t result;
+
+	do {
+		result = xhci_readl(ptr);
+		if (result == ~(uint32_t)0)
+			return -ENODEV;
+		result &= mask;
+		if (result == done)
+			return 0;
+		usec--;
+		udelay(1);
+	} while (usec > 0);
+
+	return -ETIMEDOUT;
+}
+
+/**
+ * Set the run bit and wait for the host to be running.
+ *
+ * @param hcor	pointer to host controller operation registers
+ * @return status of the Handshake
+ */
+static int xhci_start(struct xhci_hcor *hcor)
+{
+	u32 temp;
+	int ret;
+
+	puts("Starting the controller\n");
+	temp = xhci_readl(&hcor->or_usbcmd);
+	temp |= (CMD_RUN);
+	xhci_writel(&hcor->or_usbcmd, temp);
+
+	/*
+	 * Wait for the HCHalted Status bit to be 0 to indicate the host is
+	 * running.
+	 */
+	ret = handshake(&hcor->or_usbsts, STS_HALT, 0, XHCI_MAX_HALT_USEC);
+	if (ret)
+		debug("Host took too long to start, "
+				"waited %u microseconds.\n",
+				XHCI_MAX_HALT_USEC);
+	return ret;
+}
+
+/**
+ * Resets the XHCI Controller
+ *
+ * @param hcor	pointer to host controller operation registers
+ * @return -EBUSY if XHCI Controller is not halted else status of handshake
+ */
+int xhci_reset(struct xhci_hcor *hcor)
+{
+	u32 cmd;
+	u32 state;
+	int ret;
+
+	/* Halting the Host first */
+	debug("// Halt the HC\n");
+	state = xhci_readl(&hcor->or_usbsts) & STS_HALT;
+	if (!state) {
+		cmd = xhci_readl(&hcor->or_usbcmd);
+		cmd &= ~CMD_RUN;
+		xhci_writel(&hcor->or_usbcmd, cmd);
+	}
+
+	ret = handshake(&hcor->or_usbsts,
+			STS_HALT, STS_HALT, XHCI_MAX_HALT_USEC);
+	if (ret) {
+		printf("Host not halted after %u microseconds.\n",
+				XHCI_MAX_HALT_USEC);
+		return -EBUSY;
+	}
+
+	debug("// Reset the HC\n");
+	cmd = xhci_readl(&hcor->or_usbcmd);
+	cmd |= CMD_RESET;
+	xhci_writel(&hcor->or_usbcmd, cmd);
+
+	ret = handshake(&hcor->or_usbcmd, CMD_RESET, 0, XHCI_MAX_RESET_USEC);
+	if (ret)
+		return ret;
+
+	/*
+	 * xHCI cannot write to any doorbells or operational registers other
+	 * than status until the "Controller Not Ready" flag is cleared.
+	 */
+	return handshake(&hcor->or_usbsts, STS_CNR, 0, XHCI_MAX_RESET_USEC);
+}
+
+/**
+ * Used for passing endpoint bitmasks between the core and HCDs.
+ * Find the index for an endpoint given its descriptor.
+ * Use the return value to right shift 1 for the bitmask.
+ *
+ * Index  = (epnum * 2) + direction - 1,
+ * where direction = 0 for OUT, 1 for IN.
+ * For control endpoints, the IN index is used (OUT index is unused), so
+ * index = (epnum * 2) + direction - 1 = (epnum * 2) + 1 - 1 = (epnum * 2)
+ *
+ * @param desc	USB enpdoint Descriptor
+ * @return index of the Endpoint
+ */
+static unsigned int xhci_get_ep_index(struct usb_endpoint_descriptor *desc)
+{
+	unsigned int index;
+
+	if (usb_endpoint_xfer_control(desc))
+		index = (unsigned int)(usb_endpoint_num(desc) * 2);
+	else
+		index = (unsigned int)((usb_endpoint_num(desc) * 2) -
+				(usb_endpoint_dir_in(desc) ? 0 : 1));
+
+	return index;
+}
+
+/**
+ * Issue a configure endpoint command or evaluate context command
+ * and wait for it to finish.
+ *
+ * @param udev	pointer to the Device Data Structure
+ * @param ctx_change	flag to indicate the Context has changed or NOT
+ * @return 0 on success, -1 on failure
+ */
+static int xhci_configure_endpoints(struct usb_device *udev, bool ctx_change)
+{
+	struct xhci_container_ctx *in_ctx;
+	struct xhci_virt_device *virt_dev;
+	struct xhci_ctrl *ctrl = udev->controller;
+	union xhci_trb *event;
+
+	virt_dev = ctrl->devs[udev->slot_id];
+	in_ctx = virt_dev->in_ctx;
+
+	xhci_flush_cache((uint32_t)in_ctx->bytes, in_ctx->size);
+	xhci_queue_command(ctrl, in_ctx->bytes, udev->slot_id, 0,
+			   ctx_change ? TRB_EVAL_CONTEXT : TRB_CONFIG_EP);
+	event = xhci_wait_for_event(ctrl, TRB_COMPLETION);
+	BUG_ON(TRB_TO_SLOT_ID(le32_to_cpu(event->event_cmd.flags))
+		!= udev->slot_id);
+
+	switch (GET_COMP_CODE(le32_to_cpu(event->event_cmd.status))) {
+	case COMP_SUCCESS:
+		debug("Successful %s command\n",
+			ctx_change ? "Evaluate Context" : "Configure Endpoint");
+		break;
+	default:
+		printf("ERROR: %s command returned completion code %d.\n",
+			ctx_change ? "Evaluate Context" : "Configure Endpoint",
+			GET_COMP_CODE(le32_to_cpu(event->event_cmd.status)));
+		return -EINVAL;
+	}
+
+	xhci_acknowledge_event(ctrl);
+
+	return 0;
+}
+
+/**
+ * Configure the endpoint, programming the device contexts.
+ *
+ * @param udev	pointer to the USB device structure
+ * @return returns the status of the xhci_configure_endpoints
+ */
+static int xhci_set_configuration(struct usb_device *udev)
+{
+	struct xhci_container_ctx *in_ctx;
+	struct xhci_container_ctx *out_ctx;
+	struct xhci_input_control_ctx *ctrl_ctx;
+	struct xhci_slot_ctx *slot_ctx;
+	struct xhci_ep_ctx *ep_ctx[MAX_EP_CTX_NUM];
+	int cur_ep;
+	int max_ep_flag = 0;
+	int ep_index;
+	unsigned int dir;
+	unsigned int ep_type;
+	struct xhci_ctrl *ctrl = udev->controller;
+	int num_of_ep;
+	int ep_flag = 0;
+	u64 trb_64 = 0;
+	int slot_id = udev->slot_id;
+	struct xhci_virt_device *virt_dev = ctrl->devs[slot_id];
+	struct usb_interface *ifdesc;
+
+	out_ctx = virt_dev->out_ctx;
+	in_ctx = virt_dev->in_ctx;
+
+	num_of_ep = udev->config.if_desc[0].no_of_ep;
+	ifdesc = &udev->config.if_desc[0];
+
+	ctrl_ctx = xhci_get_input_control_ctx(in_ctx);
+	/* Zero the input context control */
+	ctrl_ctx->add_flags = 0;
+	ctrl_ctx->drop_flags = 0;
+
+	/* EP_FLAG gives values 1 & 4 for EP1OUT and EP2IN */
+	for (cur_ep = 0; cur_ep < num_of_ep; cur_ep++) {
+		ep_flag = xhci_get_ep_index(&ifdesc->ep_desc[cur_ep]);
+		ctrl_ctx->add_flags |= cpu_to_le32(1 << (ep_flag + 1));
+		if (max_ep_flag < ep_flag)
+			max_ep_flag = ep_flag;
+	}
+
+	xhci_inval_cache((uint32_t)out_ctx->bytes, out_ctx->size);
+
+	/* slot context */
+	xhci_slot_copy(ctrl, in_ctx, out_ctx);
+	slot_ctx = xhci_get_slot_ctx(ctrl, in_ctx);
+	slot_ctx->dev_info &= ~(LAST_CTX_MASK);
+	slot_ctx->dev_info |= cpu_to_le32(LAST_CTX(max_ep_flag + 1) | 0);
+
+	xhci_endpoint_copy(ctrl, in_ctx, out_ctx, 0);
+
+	/* filling up ep contexts */
+	for (cur_ep = 0; cur_ep < num_of_ep; cur_ep++) {
+		struct usb_endpoint_descriptor *endpt_desc = NULL;
+
+		endpt_desc = &ifdesc->ep_desc[cur_ep];
+		trb_64 = 0;
+
+		ep_index = xhci_get_ep_index(endpt_desc);
+		ep_ctx[ep_index] = xhci_get_ep_ctx(ctrl, in_ctx, ep_index);
+
+		/* Allocate the ep rings */
+		virt_dev->eps[ep_index].ring = xhci_ring_alloc(1, true);
+		if (!virt_dev->eps[ep_index].ring)
+			return -ENOMEM;
+
+		/*NOTE: ep_desc[0] actually represents EP1 and so on */
+		dir = (((endpt_desc->bEndpointAddress) & (0x80)) >> 7);
+		ep_type = (((endpt_desc->bmAttributes) & (0x3)) | (dir << 2));
+		ep_ctx[ep_index]->ep_info2 =
+			cpu_to_le32(ep_type << EP_TYPE_SHIFT);
+		ep_ctx[ep_index]->ep_info2 |=
+			cpu_to_le32(MAX_PACKET
+			(get_unaligned(&endpt_desc->wMaxPacketSize)));
+
+		ep_ctx[ep_index]->ep_info2 |=
+			cpu_to_le32(((0 & MAX_BURST_MASK) << MAX_BURST_SHIFT) |
+			((3 & ERROR_COUNT_MASK) << ERROR_COUNT_SHIFT));
+
+		trb_64 = (uintptr_t)
+				virt_dev->eps[ep_index].ring->enqueue;
+		ep_ctx[ep_index]->deq = cpu_to_le64(trb_64 |
+				virt_dev->eps[ep_index].ring->cycle_state);
+	}
+
+	return xhci_configure_endpoints(udev, false);
+}
+
+/**
+ * Issue an Address Device command (which will issue a SetAddress request to
+ * the device).
+ *
+ * @param udev pointer to the Device Data Structure
+ * @return 0 if successful else error code on failure
+ */
+static int xhci_address_device(struct usb_device *udev)
+{
+	int ret = 0;
+	struct xhci_ctrl *ctrl = udev->controller;
+	struct xhci_slot_ctx *slot_ctx;
+	struct xhci_input_control_ctx *ctrl_ctx;
+	struct xhci_virt_device *virt_dev;
+	int slot_id = udev->slot_id;
+	union xhci_trb *event;
+
+	virt_dev = ctrl->devs[slot_id];
+
+	/*
+	 * This is the first Set Address since device plug-in
+	 * so setting up the slot context.
+	 */
+	debug("Setting up addressable devices\n");
+	xhci_setup_addressable_virt_dev(udev);
+
+	ctrl_ctx = xhci_get_input_control_ctx(virt_dev->in_ctx);
+	ctrl_ctx->add_flags = cpu_to_le32(SLOT_FLAG | EP0_FLAG);
+	ctrl_ctx->drop_flags = 0;
+
+	xhci_queue_command(ctrl, (void *)ctrl_ctx, slot_id, 0, TRB_ADDR_DEV);
+	event = xhci_wait_for_event(ctrl, TRB_COMPLETION);
+	BUG_ON(TRB_TO_SLOT_ID(le32_to_cpu(event->event_cmd.flags)) != slot_id);
+
+	switch (GET_COMP_CODE(le32_to_cpu(event->event_cmd.status))) {
+	case COMP_CTX_STATE:
+	case COMP_EBADSLT:
+		printf("Setup ERROR: address device command for slot %d.\n",
+								slot_id);
+		ret = -EINVAL;
+		break;
+	case COMP_TX_ERR:
+		puts("Device not responding to set address.\n");
+		ret = -EPROTO;
+		break;
+	case COMP_DEV_ERR:
+		puts("ERROR: Incompatible device"
+					"for address device command.\n");
+		ret = -ENODEV;
+		break;
+	case COMP_SUCCESS:
+		debug("Successful Address Device command\n");
+		udev->status = 0;
+		break;
+	default:
+		printf("ERROR: unexpected command completion code 0x%x.\n",
+			GET_COMP_CODE(le32_to_cpu(event->event_cmd.status)));
+		ret = -EINVAL;
+		break;
+	}
+
+	xhci_acknowledge_event(ctrl);
+
+	if (ret < 0)
+		/*
+		 * TODO: Unsuccessful Address Device command shall leave the
+		 * slot in default state. So, issue Disable Slot command now.
+		 */
+		return ret;
+
+	xhci_inval_cache((uint32_t)virt_dev->out_ctx->bytes,
+				virt_dev->out_ctx->size);
+	slot_ctx = xhci_get_slot_ctx(ctrl, virt_dev->out_ctx);
+
+	debug("xHC internal address is: %d\n",
+		le32_to_cpu(slot_ctx->dev_state) & DEV_ADDR_MASK);
+
+	return 0;
+}
+
+/**
+ * Issue Enable slot command to the controller to allocate
+ * device slot and assign the slot id. It fails if the xHC
+ * ran out of device slots, the Enable Slot command timed out,
+ * or allocating memory failed.
+ *
+ * @param udev	pointer to the Device Data Structure
+ * @return Returns 0 on succes else return error code on failure
+ */
+int usb_alloc_device(struct usb_device *udev)
+{
+	union xhci_trb *event;
+	struct xhci_ctrl *ctrl = udev->controller;
+	int ret;
+
+	/*
+	 * Root hub will be first device to be initailized.
+	 * If this device is root-hub, don't do any xHC related
+	 * stuff.
+	 */
+	if (ctrl->rootdev == 0) {
+		udev->speed = USB_SPEED_SUPER;
+		return 0;
+	}
+
+	xhci_queue_command(ctrl, NULL, 0, 0, TRB_ENABLE_SLOT);
+	event = xhci_wait_for_event(ctrl, TRB_COMPLETION);
+	BUG_ON(GET_COMP_CODE(le32_to_cpu(event->event_cmd.status))
+		!= COMP_SUCCESS);
+
+	udev->slot_id = TRB_TO_SLOT_ID(le32_to_cpu(event->event_cmd.flags));
+
+	xhci_acknowledge_event(ctrl);
+
+	ret = xhci_alloc_virt_device(udev);
+	if (ret < 0) {
+		/*
+		 * TODO: Unsuccessful Address Device command shall leave
+		 * the slot in default. So, issue Disable Slot command now.
+		 */
+		puts("Could not allocate xHCI USB device data structures\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+/*
+ * Full speed devices may have a max packet size greater than 8 bytes, but the
+ * USB core doesn't know that until it reads the first 8 bytes of the
+ * descriptor.  If the usb_device's max packet size changes after that point,
+ * we need to issue an evaluate context command and wait on it.
+ *
+ * @param udev	pointer to the Device Data Structure
+ * @return returns the status of the xhci_configure_endpoints
+ */
+int xhci_check_maxpacket(struct usb_device *udev)
+{
+	struct xhci_ctrl *ctrl = udev->controller;
+	unsigned int slot_id = udev->slot_id;
+	int ep_index = 0;	/* control endpoint */
+	struct xhci_container_ctx *in_ctx;
+	struct xhci_container_ctx *out_ctx;
+	struct xhci_input_control_ctx *ctrl_ctx;
+	struct xhci_ep_ctx *ep_ctx;
+	int max_packet_size;
+	int hw_max_packet_size;
+	int ret = 0;
+	struct usb_interface *ifdesc;
+
+	ifdesc = &udev->config.if_desc[0];
+
+	out_ctx = ctrl->devs[slot_id]->out_ctx;
+	xhci_inval_cache((uint32_t)out_ctx->bytes, out_ctx->size);
+
+	ep_ctx = xhci_get_ep_ctx(ctrl, out_ctx, ep_index);
+	hw_max_packet_size = MAX_PACKET_DECODED(le32_to_cpu(ep_ctx->ep_info2));
+	max_packet_size = usb_endpoint_maxp(&ifdesc->ep_desc[0]);
+	if (hw_max_packet_size != max_packet_size) {
+		debug("Max Packet Size for ep 0 changed.\n");
+		debug("Max packet size in usb_device = %d\n", max_packet_size);
+		debug("Max packet size in xHCI HW = %d\n", hw_max_packet_size);
+		debug("Issuing evaluate context command.\n");
+
+		/* Set up the modified control endpoint 0 */
+		xhci_endpoint_copy(ctrl, ctrl->devs[slot_id]->in_ctx,
+				ctrl->devs[slot_id]->out_ctx, ep_index);
+		in_ctx = ctrl->devs[slot_id]->in_ctx;
+		ep_ctx = xhci_get_ep_ctx(ctrl, in_ctx, ep_index);
+		ep_ctx->ep_info2 &= cpu_to_le32(~MAX_PACKET_MASK);
+		ep_ctx->ep_info2 |= cpu_to_le32(MAX_PACKET(max_packet_size));
+
+		/*
+		 * Set up the input context flags for the command
+		 * FIXME: This won't work if a non-default control endpoint
+		 * changes max packet sizes.
+		 */
+		ctrl_ctx = xhci_get_input_control_ctx(in_ctx);
+		ctrl_ctx->add_flags = cpu_to_le32(EP0_FLAG);
+		ctrl_ctx->drop_flags = 0;
+
+		ret = xhci_configure_endpoints(udev, true);
+	}
+	return ret;
+}
+
+/**
+ * Clears the Change bits of the Port Status Register
+ *
+ * @param wValue	request value
+ * @param wIndex	request index
+ * @param addr		address of posrt status register
+ * @param port_status	state of port status register
+ * @return none
+ */
+static void xhci_clear_port_change_bit(u16 wValue,
+		u16 wIndex, volatile uint32_t *addr, u32 port_status)
+{
+	char *port_change_bit;
+	u32 status;
+
+	switch (wValue) {
+	case USB_PORT_FEAT_C_RESET:
+		status = PORT_RC;
+		port_change_bit = "reset";
+		break;
+	case USB_PORT_FEAT_C_CONNECTION:
+		status = PORT_CSC;
+		port_change_bit = "connect";
+		break;
+	case USB_PORT_FEAT_C_OVER_CURRENT:
+		status = PORT_OCC;
+		port_change_bit = "over-current";
+		break;
+	case USB_PORT_FEAT_C_ENABLE:
+		status = PORT_PEC;
+		port_change_bit = "enable/disable";
+		break;
+	case USB_PORT_FEAT_C_SUSPEND:
+		status = PORT_PLC;
+		port_change_bit = "suspend/resume";
+		break;
+	default:
+		/* Should never happen */
+		return;
+	}
+
+	/* Change bits are all write 1 to clear */
+	xhci_writel(addr, port_status | status);
+
+	port_status = xhci_readl(addr);
+	debug("clear port %s change, actual port %d status  = 0x%x\n",
+			port_change_bit, wIndex, port_status);
+}
+
+/**
+ * Save Read Only (RO) bits and save read/write bits where
+ * writing a 0 clears the bit and writing a 1 sets the bit (RWS).
+ * For all other types (RW1S, RW1CS, RW, and RZ), writing a '0' has no effect.
+ *
+ * @param state	state of the Port Status and Control Regsiter
+ * @return a value that would result in the port being in the
+ *	   same state, if the value was written to the port
+ *	   status control register.
+ */
+static u32 xhci_port_state_to_neutral(u32 state)
+{
+	/* Save read-only status and port state */
+	return (state & XHCI_PORT_RO) | (state & XHCI_PORT_RWS);
+}
+
+/**
+ * Submits the Requests to the XHCI Host Controller
+ *
+ * @param udev pointer to the USB device structure
+ * @param pipe contains the DIR_IN or OUT , devnum
+ * @param buffer buffer to be read/written based on the request
+ * @return returns 0 if successful else -1 on failure
+ */
+static int xhci_submit_root(struct usb_device *udev, unsigned long pipe,
+			void *buffer, struct devrequest *req)
+{
+	uint8_t tmpbuf[4];
+	u16 typeReq;
+	void *srcptr = NULL;
+	int len, srclen;
+	uint32_t reg;
+	volatile uint32_t *status_reg;
+	struct xhci_ctrl *ctrl = udev->controller;
+	struct xhci_hcor *hcor = ctrl->hcor;
+
+	if (((req->requesttype & USB_RT_PORT) &&
+	     le16_to_cpu(req->index)) > CONFIG_SYS_USB_XHCI_MAX_ROOT_PORTS) {
+		printf("The request port(%d) is not configured\n",
+			le16_to_cpu(req->index) - 1);
+		return -EINVAL;
+	}
+
+	status_reg = (volatile uint32_t *)
+		     (&hcor->portregs[le16_to_cpu(req->index) - 1].or_portsc);
+	srclen = 0;
+
+	typeReq = req->request | req->requesttype << 8;
+
+	switch (typeReq) {
+	case DeviceRequest | USB_REQ_GET_DESCRIPTOR:
+		switch (le16_to_cpu(req->value) >> 8) {
+		case USB_DT_DEVICE:
+			debug("USB_DT_DEVICE request\n");
+			srcptr = &descriptor.device;
+			srclen = 0x12;
+			break;
+		case USB_DT_CONFIG:
+			debug("USB_DT_CONFIG config\n");
+			srcptr = &descriptor.config;
+			srclen = 0x19;
+			break;
+		case USB_DT_STRING:
+			debug("USB_DT_STRING config\n");
+			switch (le16_to_cpu(req->value) & 0xff) {
+			case 0:	/* Language */
+				srcptr = "\4\3\11\4";
+				srclen = 4;
+				break;
+			case 1:	/* Vendor String  */
+				srcptr = "\16\3u\0-\0b\0o\0o\0t\0";
+				srclen = 14;
+				break;
+			case 2:	/* Product Name */
+				srcptr = "\52\3X\0H\0C\0I\0 "
+					 "\0H\0o\0s\0t\0 "
+					 "\0C\0o\0n\0t\0r\0o\0l\0l\0e\0r\0";
+				srclen = 42;
+				break;
+			default:
+				printf("unknown value DT_STRING %x\n",
+					le16_to_cpu(req->value));
+				goto unknown;
+			}
+			break;
+		default:
+			printf("unknown value %x\n", le16_to_cpu(req->value));
+			goto unknown;
+		}
+		break;
+	case USB_REQ_GET_DESCRIPTOR | ((USB_DIR_IN | USB_RT_HUB) << 8):
+		switch (le16_to_cpu(req->value) >> 8) {
+		case USB_DT_HUB:
+			debug("USB_DT_HUB config\n");
+			srcptr = &descriptor.hub;
+			srclen = 0x8;
+			break;
+		default:
+			printf("unknown value %x\n", le16_to_cpu(req->value));
+			goto unknown;
+		}
+		break;
+	case USB_REQ_SET_ADDRESS | (USB_RECIP_DEVICE << 8):
+		debug("USB_REQ_SET_ADDRESS\n");
+		ctrl->rootdev = le16_to_cpu(req->value);
+		break;
+	case DeviceOutRequest | USB_REQ_SET_CONFIGURATION:
+		/* Do nothing */
+		break;
+	case USB_REQ_GET_STATUS | ((USB_DIR_IN | USB_RT_HUB) << 8):
+		tmpbuf[0] = 1;	/* USB_STATUS_SELFPOWERED */
+		tmpbuf[1] = 0;
+		srcptr = tmpbuf;
+		srclen = 2;
+		break;
+	case USB_REQ_GET_STATUS | ((USB_RT_PORT | USB_DIR_IN) << 8):
+		memset(tmpbuf, 0, 4);
+		reg = xhci_readl(status_reg);
+		if (reg & PORT_CONNECT) {
+			tmpbuf[0] |= USB_PORT_STAT_CONNECTION;
+			switch (reg & DEV_SPEED_MASK) {
+			case XDEV_FS:
+				debug("SPEED = FULLSPEED\n");
+				break;
+			case XDEV_LS:
+				debug("SPEED = LOWSPEED\n");
+				tmpbuf[1] |= USB_PORT_STAT_LOW_SPEED >> 8;
+				break;
+			case XDEV_HS:
+				debug("SPEED = HIGHSPEED\n");
+				tmpbuf[1] |= USB_PORT_STAT_HIGH_SPEED >> 8;
+				break;
+			case XDEV_SS:
+				debug("SPEED = SUPERSPEED\n");
+				tmpbuf[1] |= USB_PORT_STAT_SUPER_SPEED >> 8;
+				break;
+			}
+		}
+		if (reg & PORT_PE)
+			tmpbuf[0] |= USB_PORT_STAT_ENABLE;
+		if ((reg & PORT_PLS_MASK) == XDEV_U3)
+			tmpbuf[0] |= USB_PORT_STAT_SUSPEND;
+		if (reg & PORT_OC)
+			tmpbuf[0] |= USB_PORT_STAT_OVERCURRENT;
+		if (reg & PORT_RESET)
+			tmpbuf[0] |= USB_PORT_STAT_RESET;
+		if (reg & PORT_POWER)
+			/*
+			 * XXX: This Port power bit (for USB 3.0 hub)
+			 * we are faking in USB 2.0 hub port status;
+			 * since there's a change in bit positions in
+			 * two:
+			 * USB 2.0 port status PP is at position[8]
+			 * USB 3.0 port status PP is at position[9]
+			 * So, we are still keeping it at position [8]
+			 */
+			tmpbuf[1] |= USB_PORT_STAT_POWER >> 8;
+		if (reg & PORT_CSC)
+			tmpbuf[2] |= USB_PORT_STAT_C_CONNECTION;
+		if (reg & PORT_PEC)
+			tmpbuf[2] |= USB_PORT_STAT_C_ENABLE;
+		if (reg & PORT_OCC)
+			tmpbuf[2] |= USB_PORT_STAT_C_OVERCURRENT;
+		if (reg & PORT_RC)
+			tmpbuf[2] |= USB_PORT_STAT_C_RESET;
+
+		srcptr = tmpbuf;
+		srclen = 4;
+		break;
+	case USB_REQ_SET_FEATURE | ((USB_DIR_OUT | USB_RT_PORT) << 8):
+		reg = xhci_readl(status_reg);
+		reg = xhci_port_state_to_neutral(reg);
+		switch (le16_to_cpu(req->value)) {
+		case USB_PORT_FEAT_ENABLE:
+			reg |= PORT_PE;
+			xhci_writel(status_reg, reg);
+			break;
+		case USB_PORT_FEAT_POWER:
+			reg |= PORT_POWER;
+			xhci_writel(status_reg, reg);
+			break;
+		case USB_PORT_FEAT_RESET:
+			reg |= PORT_RESET;
+			xhci_writel(status_reg, reg);
+			break;
+		default:
+			printf("unknown feature %x\n", le16_to_cpu(req->value));
+			goto unknown;
+		}
+		break;
+	case USB_REQ_CLEAR_FEATURE | ((USB_DIR_OUT | USB_RT_PORT) << 8):
+		reg = xhci_readl(status_reg);
+		reg = xhci_port_state_to_neutral(reg);
+		switch (le16_to_cpu(req->value)) {
+		case USB_PORT_FEAT_ENABLE:
+			reg &= ~PORT_PE;
+			break;
+		case USB_PORT_FEAT_POWER:
+			reg &= ~PORT_POWER;
+			break;
+		case USB_PORT_FEAT_C_RESET:
+		case USB_PORT_FEAT_C_CONNECTION:
+		case USB_PORT_FEAT_C_OVER_CURRENT:
+		case USB_PORT_FEAT_C_ENABLE:
+			xhci_clear_port_change_bit((le16_to_cpu(req->value)),
+							le16_to_cpu(req->index),
+							status_reg, reg);
+			break;
+		default:
+			printf("unknown feature %x\n", le16_to_cpu(req->value));
+			goto unknown;
+		}
+		xhci_writel(status_reg, reg);
+		break;
+	default:
+		puts("Unknown request\n");
+		goto unknown;
+	}
+
+	debug("scrlen = %d\n req->length = %d\n",
+		srclen, le16_to_cpu(req->length));
+
+	len = min(srclen, le16_to_cpu(req->length));
+
+	if (srcptr != NULL && len > 0)
+		memcpy(buffer, srcptr, len);
+	else
+		debug("Len is 0\n");
+
+	udev->act_len = len;
+	udev->status = 0;
+
+	return 0;
+
+unknown:
+	udev->act_len = 0;
+	udev->status = USB_ST_STALLED;
+
+	return -ENODEV;
+}
+
+/**
+ * Submits the INT request to XHCI Host cotroller
+ *
+ * @param udev	pointer to the USB device
+ * @param pipe		contains the DIR_IN or OUT , devnum
+ * @param buffer	buffer to be read/written based on the request
+ * @param length	length of the buffer
+ * @param interval	interval of the interrupt
+ * @return 0
+ */
+int
+submit_int_msg(struct usb_device *udev, unsigned long pipe, void *buffer,
+						int length, int interval)
+{
+	/*
+	 * TODO: Not addressing any interrupt type transfer requests
+	 * Add support for it later.
+	 */
+	return -EINVAL;
+}
+
+/**
+ * submit the BULK type of request to the USB Device
+ *
+ * @param udev	pointer to the USB device
+ * @param pipe		contains the DIR_IN or OUT , devnum
+ * @param buffer	buffer to be read/written based on the request
+ * @param length	length of the buffer
+ * @return returns 0 if successful else -1 on failure
+ */
+int
+submit_bulk_msg(struct usb_device *udev, unsigned long pipe, void *buffer,
+								int length)
+{
+	if (usb_pipetype(pipe) != PIPE_BULK) {
+		printf("non-bulk pipe (type=%lu)", usb_pipetype(pipe));
+		return -EINVAL;
+	}
+
+	return xhci_bulk_tx(udev, pipe, length, buffer);
+}
+
+/**
+ * submit the control type of request to the Root hub/Device based on the devnum
+ *
+ * @param udev	pointer to the USB device
+ * @param pipe		contains the DIR_IN or OUT , devnum
+ * @param buffer	buffer to be read/written based on the request
+ * @param length	length of the buffer
+ * @param setup		Request type
+ * @return returns 0 if successful else -1 on failure
+ */
+int
+submit_control_msg(struct usb_device *udev, unsigned long pipe, void *buffer,
+					int length, struct devrequest *setup)
+{
+	struct xhci_ctrl *ctrl = udev->controller;
+	int ret = 0;
+
+	if (usb_pipetype(pipe) != PIPE_CONTROL) {
+		printf("non-control pipe (type=%lu)", usb_pipetype(pipe));
+		return -EINVAL;
+	}
+
+	if (usb_pipedevice(pipe) == ctrl->rootdev)
+		return xhci_submit_root(udev, pipe, buffer, setup);
+
+	if (setup->request == USB_REQ_SET_ADDRESS)
+		return xhci_address_device(udev);
+
+	if (setup->request == USB_REQ_SET_CONFIGURATION) {
+		ret = xhci_set_configuration(udev);
+		if (ret) {
+			puts("Failed to configure xHCI endpoint\n");
+			return ret;
+		}
+	}
+
+	return xhci_ctrl_tx(udev, pipe, setup, length, buffer);
+}
+
+/**
+ * Intialises the XHCI host controller
+ * and allocates the necessary data structures
+ *
+ * @param index	index to the host controller data structure
+ * @return pointer to the intialised controller
+ */
+int usb_lowlevel_init(int index, void **controller)
+{
+	uint32_t val;
+	uint32_t val2;
+	uint32_t reg;
+	struct xhci_hccr *hccr;
+	struct xhci_hcor *hcor;
+	struct xhci_ctrl *ctrl;
+
+	if (xhci_hcd_init(index, &hccr, (struct xhci_hcor **)&hcor) != 0)
+		return -ENODEV;
+
+	if (xhci_reset(hcor) != 0)
+		return -ENODEV;
+
+	ctrl = &xhcic[index];
+
+	ctrl->hccr = hccr;
+	ctrl->hcor = hcor;
+
+	/*
+	 * Program the Number of Device Slots Enabled field in the CONFIG
+	 * register with the max value of slots the HC can handle.
+	 */
+	val = (xhci_readl(&hccr->cr_hcsparams1) & HCS_SLOTS_MASK);
+	val2 = xhci_readl(&hcor->or_config);
+	val |= (val2 & ~HCS_SLOTS_MASK);
+	xhci_writel(&hcor->or_config, val);
+
+	/* initializing xhci data structures */
+	if (xhci_mem_init(ctrl, hccr, hcor) < 0)
+		return -ENOMEM;
+
+	reg = xhci_readl(&hccr->cr_hcsparams1);
+	descriptor.hub.bNbrPorts = ((reg & HCS_MAX_PORTS_MASK) >>
+						HCS_MAX_PORTS_SHIFT);
+	printf("Register %x NbrPorts %d\n", reg, descriptor.hub.bNbrPorts);
+
+	/* Port Indicators */
+	reg = xhci_readl(&hccr->cr_hccparams);
+	if (HCS_INDICATOR(reg))
+		put_unaligned(get_unaligned(&descriptor.hub.wHubCharacteristics)
+				| 0x80, &descriptor.hub.wHubCharacteristics);
+
+	/* Port Power Control */
+	if (HCC_PPC(reg))
+		put_unaligned(get_unaligned(&descriptor.hub.wHubCharacteristics)
+				| 0x01, &descriptor.hub.wHubCharacteristics);
+
+	if (xhci_start(hcor)) {
+		xhci_reset(hcor);
+		return -ENODEV;
+	}
+
+	/* Zero'ing IRQ control register and IRQ pending register */
+	xhci_writel(&ctrl->ir_set->irq_control, 0x0);
+	xhci_writel(&ctrl->ir_set->irq_pending, 0x0);
+
+	reg = HC_VERSION(xhci_readl(&hccr->cr_capbase));
+	printf("USB XHCI %x.%02x\n", reg >> 8, reg & 0xff);
+
+	*controller = &xhcic[index];
+
+	return 0;
+}
+
+/**
+ * Stops the XHCI host controller
+ * and cleans up all the related data structures
+ *
+ * @param index	index to the host controller data structure
+ * @return none
+ */
+int usb_lowlevel_stop(int index)
+{
+	struct xhci_ctrl *ctrl = (xhcic + index);
+	u32 temp;
+
+	xhci_reset(ctrl->hcor);
+
+	debug("// Disabling event ring interrupts\n");
+	temp = xhci_readl(&ctrl->hcor->or_usbsts);
+	xhci_writel(&ctrl->hcor->or_usbsts, temp & ~STS_EINT);
+	temp = xhci_readl(&ctrl->ir_set->irq_pending);
+	xhci_writel(&ctrl->ir_set->irq_pending, ER_IRQ_DISABLE(temp));
+
+	xhci_hcd_stop(index);
+
+	xhci_cleanup(ctrl);
+
+	return 0;
+}