USB: xhci: BIOS handoff and HW initialization.

Add PCI initialization code to take control of the xHCI host controller
away from the BIOS, halt, and reset the host controller.  The xHCI spec
says that BIOSes must give up the host controller within 5 seconds.

Add some host controller glue functions to handle hardware initialization
and memory allocation for the host controller.  The current xHCI
prototypes use PCI interrupts, but the xHCI spec requires MSI-X
interrupts.  Add code to support MSI-X interrupts, but use the PCI
interrupts for now.

Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

6 files changed, 787 insertions, 2 deletions

diff --git a/drivers/usb/core/hcd.h b/drivers/usb/core/hcd.h
index 174170f14f0..7a47498b0aa 100644
--- a/drivers/usb/core/hcd.h
+++ b/drivers/usb/core/hcd.h
@@ -173,6 +173,7 @@ struct hc_driver {
 #define	HCD_LOCAL_MEM	0x0002		/* HC needs local memory */
 #define	HCD_USB11	0x0010		/* USB 1.1 */
 #define	HCD_USB2	0x0020		/* USB 2.0 */
+#define	HCD_USB3	0x0040		/* USB 3.0 */
 
 	/* called to init HCD and root hub */
 	int	(*reset) (struct usb_hcd *hcd);
diff --git a/drivers/usb/host/pci-quirks.c b/drivers/usb/host/pci-quirks.c
index 033c2846ce5..83b5f9cea85 100644
--- a/drivers/usb/host/pci-quirks.c
+++ b/drivers/usb/host/pci-quirks.c
@@ -15,6 +15,7 @@
 #include <linux/delay.h>
 #include <linux/acpi.h>
 #include "pci-quirks.h"
+#include "xhci-ext-caps.h"
 
 
 #define UHCI_USBLEGSUP		0xc0		/* legacy support */
@@ -341,7 +342,127 @@ static void __devinit quirk_usb_disable_ehci(struct pci_dev *pdev)
 	return;
 }
 
+/*
+ * handshake - spin reading a register until handshake completes
+ * @ptr: address of hc register to be read
+ * @mask: bits to look at in result of read
+ * @done: value of those bits when handshake succeeds
+ * @wait_usec: timeout in microseconds
+ * @delay_usec: delay in microseconds to wait between polling
+ *
+ * Polls a register every delay_usec microseconds.
+ * Returns 0 when the mask bits have the value done.
+ * Returns -ETIMEDOUT if this condition is not true after
+ * wait_usec microseconds have passed.
+ */
+static int handshake(void __iomem *ptr, u32 mask, u32 done,
+		int wait_usec, int delay_usec)
+{
+	u32	result;
+
+	do {
+		result = readl(ptr);
+		result &= mask;
+		if (result == done)
+			return 0;
+		udelay(delay_usec);
+		wait_usec -= delay_usec;
+	} while (wait_usec > 0);
+	return -ETIMEDOUT;
+}
+
+/**
+ * PCI Quirks for xHCI.
+ *
+ * Takes care of the handoff between the Pre-OS (i.e. BIOS) and the OS.
+ * It signals to the BIOS that the OS wants control of the host controller,
+ * and then waits 5 seconds for the BIOS to hand over control.
+ * If we timeout, assume the BIOS is broken and take control anyway.
+ */
+static void __devinit quirk_usb_handoff_xhci(struct pci_dev *pdev)
+{
+	void __iomem *base;
+	int ext_cap_offset;
+	void __iomem *op_reg_base;
+	u32 val;
+	int timeout;
+
+	if (!mmio_resource_enabled(pdev, 0))
+		return;
+
+	base = ioremap_nocache(pci_resource_start(pdev, 0),
+				pci_resource_len(pdev, 0));
+	if (base == NULL)
+		return;
 
+	/*
+	 * Find the Legacy Support Capability register -
+	 * this is optional for xHCI host controllers.
+	 */
+	ext_cap_offset = xhci_find_next_cap_offset(base, XHCI_HCC_PARAMS_OFFSET);
+	do {
+		if (!ext_cap_offset)
+			/* We've reached the end of the extended capabilities */
+			goto hc_init;
+		val = readl(base + ext_cap_offset);
+		if (XHCI_EXT_CAPS_ID(val) == XHCI_EXT_CAPS_LEGACY)
+			break;
+		ext_cap_offset = xhci_find_next_cap_offset(base, ext_cap_offset);
+	} while (1);
+
+	/* If the BIOS owns the HC, signal that the OS wants it, and wait */
+	if (val & XHCI_HC_BIOS_OWNED) {
+		writel(val & XHCI_HC_OS_OWNED, base + ext_cap_offset);
+
+		/* Wait for 5 seconds with 10 microsecond polling interval */
+		timeout = handshake(base + ext_cap_offset, XHCI_HC_BIOS_OWNED,
+				0, 5000, 10);
+
+		/* Assume a buggy BIOS and take HC ownership anyway */
+		if (timeout) {
+			dev_warn(&pdev->dev, "xHCI BIOS handoff failed"
+					" (BIOS bug ?) %08x\n", val);
+			writel(val & ~XHCI_HC_BIOS_OWNED, base + ext_cap_offset);
+		}
+	}
+
+	/* Disable any BIOS SMIs */
+	writel(XHCI_LEGACY_DISABLE_SMI,
+			base + ext_cap_offset + XHCI_LEGACY_CONTROL_OFFSET);
+
+hc_init:
+	op_reg_base = base + XHCI_HC_LENGTH(readl(base));
+
+	/* Wait for the host controller to be ready before writing any
+	 * operational or runtime registers.  Wait 5 seconds and no more.
+	 */
+	timeout = handshake(op_reg_base + XHCI_STS_OFFSET, XHCI_STS_CNR, 0,
+			5000, 10);
+	/* Assume a buggy HC and start HC initialization anyway */
+	if (timeout) {
+		val = readl(op_reg_base + XHCI_STS_OFFSET);
+		dev_warn(&pdev->dev,
+				"xHCI HW not ready after 5 sec (HC bug?) "
+				"status = 0x%x\n", val);
+	}
+
+	/* Send the halt and disable interrupts command */
+	val = readl(op_reg_base + XHCI_CMD_OFFSET);
+	val &= ~(XHCI_CMD_RUN | XHCI_IRQS);
+	writel(val, op_reg_base + XHCI_CMD_OFFSET);
+
+	/* Wait for the HC to halt - poll every 125 usec (one microframe). */
+	timeout = handshake(op_reg_base + XHCI_STS_OFFSET, XHCI_STS_HALT, 1,
+			XHCI_MAX_HALT_USEC, 125);
+	if (timeout) {
+		val = readl(op_reg_base + XHCI_STS_OFFSET);
+		dev_warn(&pdev->dev,
+				"xHCI HW did not halt within %d usec "
+				"status = 0x%x\n", XHCI_MAX_HALT_USEC, val);
+	}
+
+	iounmap(base);
+}
 
 static void __devinit quirk_usb_early_handoff(struct pci_dev *pdev)
 {
@@ -351,5 +472,7 @@ static void __devinit quirk_usb_early_handoff(struct pci_dev *pdev)
 		quirk_usb_handoff_ohci(pdev);
 	else if (pdev->class == PCI_CLASS_SERIAL_USB_EHCI)
 		quirk_usb_disable_ehci(pdev);
+	else if (pdev->class == PCI_CLASS_SERIAL_USB_XHCI)
+		quirk_usb_handoff_xhci(pdev);
 }
 DECLARE_PCI_FIXUP_FINAL(PCI_ANY_ID, PCI_ANY_ID, quirk_usb_early_handoff);
diff --git a/drivers/usb/host/xhci-hcd.c b/drivers/usb/host/xhci-hcd.c
new file mode 100644
index 00000000000..64fcc22e9d5
--- /dev/null
+++ b/drivers/usb/host/xhci-hcd.c
@@ -0,0 +1,377 @@
+/*
+ * xHCI host controller driver
+ *
+ * Copyright (C) 2008 Intel Corp.
+ *
+ * Author: Sarah Sharp
+ * Some code borrowed from the Linux EHCI driver.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/irq.h>
+#include <linux/module.h>
+
+#include "xhci.h"
+
+#define DRIVER_AUTHOR "Sarah Sharp"
+#define DRIVER_DESC "'eXtensible' Host Controller (xHC) Driver"
+
+/* TODO: copied from ehci-hcd.c - can this be refactored? */
+/*
+ * handshake - spin reading hc until handshake completes or fails
+ * @ptr: address of hc 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).
+ */
+static int handshake(struct xhci_hcd *xhci, void __iomem *ptr,
+		      u32 mask, u32 done, int usec)
+{
+	u32	result;
+
+	do {
+		result = xhci_readl(xhci, ptr);
+		if (result == ~(u32)0)		/* card removed */
+			return -ENODEV;
+		result &= mask;
+		if (result == done)
+			return 0;
+		udelay(1);
+		usec--;
+	} while (usec > 0);
+	return -ETIMEDOUT;
+}
+
+/*
+ * Force HC into halt state.
+ *
+ * Disable any IRQs and clear the run/stop bit.
+ * HC will complete any current and actively pipelined transactions, and
+ * should halt within 16 microframes of the run/stop bit being cleared.
+ * Read HC Halted bit in the status register to see when the HC is finished.
+ * XXX: shouldn't we set HC_STATE_HALT here somewhere?
+ */
+int xhci_halt(struct xhci_hcd *xhci)
+{
+	u32 halted;
+	u32 cmd;
+	u32 mask;
+
+	xhci_dbg(xhci, "// Halt the HC\n");
+	/* Disable all interrupts from the host controller */
+	mask = ~(XHCI_IRQS);
+	halted = xhci_readl(xhci, &xhci->op_regs->status) & STS_HALT;
+	if (!halted)
+		mask &= ~CMD_RUN;
+
+	cmd = xhci_readl(xhci, &xhci->op_regs->command);
+	cmd &= mask;
+	xhci_writel(xhci, cmd, &xhci->op_regs->command);
+
+	return handshake(xhci, &xhci->op_regs->status,
+			STS_HALT, STS_HALT, XHCI_MAX_HALT_USEC);
+}
+
+/*
+ * Reset a halted HC, and set the internal HC state to HC_STATE_HALT.
+ *
+ * This resets pipelines, timers, counters, state machines, etc.
+ * Transactions will be terminated immediately, and operational registers
+ * will be set to their defaults.
+ */
+int xhci_reset(struct xhci_hcd *xhci)
+{
+	u32 command;
+	u32 state;
+
+	state = xhci_readl(xhci, &xhci->op_regs->status);
+	BUG_ON((state & STS_HALT) == 0);
+
+	xhci_dbg(xhci, "// Reset the HC\n");
+	command = xhci_readl(xhci, &xhci->op_regs->command);
+	command |= CMD_RESET;
+	xhci_writel(xhci, command, &xhci->op_regs->command);
+	/* XXX: Why does EHCI set this here?  Shouldn't other code do this? */
+	xhci_to_hcd(xhci)->state = HC_STATE_HALT;
+
+	return handshake(xhci, &xhci->op_regs->command, CMD_RESET, 0, 250 * 1000);
+}
+
+/*
+ * Stop the HC from processing the endpoint queues.
+ */
+static void xhci_quiesce(struct xhci_hcd *xhci)
+{
+	/*
+	 * Queues are per endpoint, so we need to disable an endpoint or slot.
+	 *
+	 * To disable a slot, we need to insert a disable slot command on the
+	 * command ring and ring the doorbell.  This will also free any internal
+	 * resources associated with the slot (which might not be what we want).
+	 *
+	 * A Release Endpoint command sounds better - doesn't free internal HC
+	 * memory, but removes the endpoints from the schedule and releases the
+	 * bandwidth, disables the doorbells, and clears the endpoint enable
+	 * flag.  Usually used prior to a set interface command.
+	 *
+	 * TODO: Implement after command ring code is done.
+	 */
+	BUG_ON(!HC_IS_RUNNING(xhci_to_hcd(xhci)->state));
+	xhci_dbg(xhci, "Finished quiescing -- code not written yet\n");
+}
+
+#if 0
+/* Set up MSI-X table for entry 0 (may claim other entries later) */
+static int xhci_setup_msix(struct xhci_hcd *xhci)
+{
+	int ret;
+	struct pci_dev *pdev = to_pci_dev(xhci_to_hcd(xhci)->self.controller);
+
+	xhci->msix_count = 0;
+	/* XXX: did I do this right?  ixgbe does kcalloc for more than one */
+	xhci->msix_entries = kmalloc(sizeof(struct msix_entry), GFP_KERNEL);
+	if (!xhci->msix_entries) {
+		xhci_err(xhci, "Failed to allocate MSI-X entries\n");
+		return -ENOMEM;
+	}
+	xhci->msix_entries[0].entry = 0;
+
+	ret = pci_enable_msix(pdev, xhci->msix_entries, xhci->msix_count);
+	if (ret) {
+		xhci_err(xhci, "Failed to enable MSI-X\n");
+		goto free_entries;
+	}
+
+	/*
+	 * Pass the xhci pointer value as the request_irq "cookie".
+	 * If more irqs are added, this will need to be unique for each one.
+	 */
+	ret = request_irq(xhci->msix_entries[0].vector, &xhci_irq, 0,
+			"xHCI", xhci_to_hcd(xhci));
+	if (ret) {
+		xhci_err(xhci, "Failed to allocate MSI-X interrupt\n");
+		goto disable_msix;
+	}
+	xhci_dbg(xhci, "Finished setting up MSI-X\n");
+	return 0;
+
+disable_msix:
+	pci_disable_msix(pdev);
+free_entries:
+	kfree(xhci->msix_entries);
+	xhci->msix_entries = NULL;
+	return ret;
+}
+
+/* XXX: code duplication; can xhci_setup_msix call this? */
+/* Free any IRQs and disable MSI-X */
+static void xhci_cleanup_msix(struct xhci_hcd *xhci)
+{
+	struct pci_dev *pdev = to_pci_dev(xhci_to_hcd(xhci)->self.controller);
+	if (!xhci->msix_entries)
+		return;
+
+	free_irq(xhci->msix_entries[0].vector, xhci);
+	pci_disable_msix(pdev);
+	kfree(xhci->msix_entries);
+	xhci->msix_entries = NULL;
+	xhci_dbg(xhci, "Finished cleaning up MSI-X\n");
+}
+#endif
+
+/*
+ * Initialize memory for HCD and xHC (one-time init).
+ *
+ * Program the PAGESIZE register, initialize the device context array, create
+ * device contexts (?), set up a command ring segment (or two?), create event
+ * ring (one for now).
+ */
+int xhci_init(struct usb_hcd *hcd)
+{
+	struct xhci_hcd *xhci = hcd_to_xhci(hcd);
+	int retval = 0;
+
+	xhci_dbg(xhci, "xhci_init\n");
+	spin_lock_init(&xhci->lock);
+	retval = xhci_mem_init(xhci, GFP_KERNEL);
+	xhci_dbg(xhci, "Finished xhci_init\n");
+
+	return retval;
+}
+
+/*
+ * Start the HC after it was halted.
+ *
+ * This function is called by the USB core when the HC driver is added.
+ * Its opposite is xhci_stop().
+ *
+ * xhci_init() must be called once before this function can be called.
+ * Reset the HC, enable device slot contexts, program DCBAAP, and
+ * set command ring pointer and event ring pointer.
+ *
+ * Setup MSI-X vectors and enable interrupts.
+ */
+int xhci_run(struct usb_hcd *hcd)
+{
+	u32 temp;
+	struct xhci_hcd *xhci = hcd_to_xhci(hcd);
+	xhci_dbg(xhci, "xhci_run\n");
+
+#if 0	/* FIXME: MSI not setup yet */
+	/* Do this at the very last minute */
+	ret = xhci_setup_msix(xhci);
+	if (!ret)
+		return ret;
+
+	return -ENOSYS;
+#endif
+	xhci_dbg(xhci, "// Set the interrupt modulation register\n");
+	temp = xhci_readl(xhci, &xhci->ir_set->irq_control);
+	temp &= 0xffff;
+	temp |= (u32) 160;
+	xhci_writel(xhci, temp, &xhci->ir_set->irq_control);
+
+	/* Set the HCD state before we enable the irqs */
+	hcd->state = HC_STATE_RUNNING;
+	temp = xhci_readl(xhci, &xhci->op_regs->command);
+	temp |= (CMD_EIE);
+	xhci_dbg(xhci, "// Enable interrupts, cmd = 0x%x.\n",
+			temp);
+	xhci_writel(xhci, temp, &xhci->op_regs->command);
+
+	temp = xhci_readl(xhci, &xhci->ir_set->irq_pending);
+	xhci_dbg(xhci, "// Enabling event ring interrupter 0x%x"
+			" by writing 0x%x to irq_pending\n",
+			(unsigned int) xhci->ir_set,
+			(unsigned int) ER_IRQ_ENABLE(temp));
+	xhci_writel(xhci, ER_IRQ_ENABLE(temp),
+			&xhci->ir_set->irq_pending);
+	xhci_print_ir_set(xhci, xhci->ir_set, 0);
+
+	temp = xhci_readl(xhci, &xhci->op_regs->command);
+	temp |= (CMD_RUN);
+	xhci_dbg(xhci, "// Turn on HC, cmd = 0x%x.\n",
+			temp);
+	xhci_writel(xhci, temp, &xhci->op_regs->command);
+	/* Flush PCI posted writes */
+	temp = xhci_readl(xhci, &xhci->op_regs->command);
+	xhci_dbg(xhci, "// @%x = 0x%x\n",
+			(unsigned int) &xhci->op_regs->command, temp);
+
+	xhci_dbg(xhci, "Finished xhci_run\n");
+	return 0;
+}
+
+/*
+ * Stop xHCI driver.
+ *
+ * This function is called by the USB core when the HC driver is removed.
+ * Its opposite is xhci_run().
+ *
+ * Disable device contexts, disable IRQs, and quiesce the HC.
+ * Reset the HC, finish any completed transactions, and cleanup memory.
+ */
+void xhci_stop(struct usb_hcd *hcd)
+{
+	u32 temp;
+	struct xhci_hcd *xhci = hcd_to_xhci(hcd);
+
+	spin_lock_irq(&xhci->lock);
+	if (HC_IS_RUNNING(hcd->state))
+		xhci_quiesce(xhci);
+	xhci_halt(xhci);
+	xhci_reset(xhci);
+	spin_unlock_irq(&xhci->lock);
+
+#if 0	/* No MSI yet */
+	xhci_cleanup_msix(xhci);
+#endif
+	xhci_dbg(xhci, "// Disabling event ring interrupts\n");
+	temp = xhci_readl(xhci, &xhci->op_regs->status);
+	xhci_writel(xhci, temp & ~STS_EINT, &xhci->op_regs->status);
+	temp = xhci_readl(xhci, &xhci->ir_set->irq_pending);
+	xhci_writel(xhci, ER_IRQ_DISABLE(temp),
+			&xhci->ir_set->irq_pending);
+	xhci_print_ir_set(xhci, xhci->ir_set, 0);
+
+	xhci_dbg(xhci, "cleaning up memory\n");
+	xhci_mem_cleanup(xhci);
+	xhci_dbg(xhci, "xhci_stop completed - status = %x\n",
+		    xhci_readl(xhci, &xhci->op_regs->status));
+}
+
+/*
+ * Shutdown HC (not bus-specific)
+ *
+ * This is called when the machine is rebooting or halting.  We assume that the
+ * machine will be powered off, and the HC's internal state will be reset.
+ * Don't bother to free memory.
+ */
+void xhci_shutdown(struct usb_hcd *hcd)
+{
+	struct xhci_hcd *xhci = hcd_to_xhci(hcd);
+
+	spin_lock_irq(&xhci->lock);
+	xhci_halt(xhci);
+	spin_unlock_irq(&xhci->lock);
+
+#if 0
+	xhci_cleanup_msix(xhci);
+#endif
+
+	xhci_dbg(xhci, "xhci_shutdown completed - status = %x\n",
+		    xhci_readl(xhci, &xhci->op_regs->status));
+}
+
+int xhci_get_frame(struct usb_hcd *hcd)
+{
+	struct xhci_hcd *xhci = hcd_to_xhci(hcd);
+	/* EHCI mods by the periodic size.  Why? */
+	return xhci_readl(xhci, &xhci->run_regs->microframe_index) >> 3;
+}
+
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_LICENSE("GPL");
+
+static int __init xhci_hcd_init(void)
+{
+#ifdef CONFIG_PCI
+	int retval = 0;
+
+	retval = xhci_register_pci();
+
+	if (retval < 0) {
+		printk(KERN_DEBUG "Problem registering PCI driver.");
+		return retval;
+	}
+#endif
+	return 0;
+}
+module_init(xhci_hcd_init);
+
+static void __exit xhci_hcd_cleanup(void)
+{
+#ifdef CONFIG_PCI
+	xhci_unregister_pci();
+#endif
+}
+module_exit(xhci_hcd_cleanup);
diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
new file mode 100644
index 00000000000..0e383f9c380
--- /dev/null
+++ b/drivers/usb/host/xhci-mem.c
@@ -0,0 +1,75 @@
+/*
+ * xHCI host controller driver
+ *
+ * Copyright (C) 2008 Intel Corp.
+ *
+ * Author: Sarah Sharp
+ * Some code borrowed from the Linux EHCI driver.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/usb.h>
+
+#include "xhci.h"
+
+void xhci_mem_cleanup(struct xhci_hcd *xhci)
+{
+	xhci->page_size = 0;
+	xhci->page_shift = 0;
+}
+
+int xhci_mem_init(struct xhci_hcd *xhci, gfp_t flags)
+{
+	unsigned int	val, val2;
+	u32 page_size;
+	int i;
+
+	page_size = xhci_readl(xhci, &xhci->op_regs->page_size);
+	xhci_dbg(xhci, "Supported page size register = 0x%x\n", page_size);
+	for (i = 0; i < 16; i++) {
+		if ((0x1 & page_size) != 0)
+			break;
+		page_size = page_size >> 1;
+	}
+	if (i < 16)
+		xhci_dbg(xhci, "Supported page size of %iK\n", (1 << (i+12)) / 1024);
+	else
+		xhci_warn(xhci, "WARN: no supported page size\n");
+	/* Use 4K pages, since that's common and the minimum the HC supports */
+	xhci->page_shift = 12;
+	xhci->page_size = 1 << xhci->page_shift;
+	xhci_dbg(xhci, "HCD page size set to %iK\n", xhci->page_size / 1024);
+
+	/*
+	 * Program the Number of Device Slots Enabled field in the CONFIG
+	 * register with the max value of slots the HC can handle.
+	 */
+	val = HCS_MAX_SLOTS(xhci_readl(xhci, &xhci->cap_regs->hcs_params1));
+	xhci_dbg(xhci, "// xHC can handle at most %d device slots.\n",
+			(unsigned int) val);
+	val2 = xhci_readl(xhci, &xhci->op_regs->config_reg);
+	val |= (val2 & ~HCS_SLOTS_MASK);
+	xhci_dbg(xhci, "// Setting Max device slots reg = 0x%x.\n",
+			(unsigned int) val);
+	xhci_writel(xhci, val, &xhci->op_regs->config_reg);
+
+	xhci->ir_set = &xhci->run_regs->ir_set[0];
+
+	return 0;
+fail:
+	xhci_warn(xhci, "Couldn't initialize memory\n");
+	xhci_mem_cleanup(xhci);
+	return -ENOMEM;
+}
diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
new file mode 100644
index 00000000000..4015082adf6
--- /dev/null
+++ b/drivers/usb/host/xhci-pci.c
@@ -0,0 +1,150 @@
+/*
+ * xHCI host controller driver PCI Bus Glue.
+ *
+ * Copyright (C) 2008 Intel Corp.
+ *
+ * Author: Sarah Sharp
+ * Some code borrowed from the Linux EHCI driver.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/pci.h>
+
+#include "xhci.h"
+
+static const char hcd_name[] = "xhci_hcd";
+
+/* called after powerup, by probe or system-pm "wakeup" */
+static int xhci_pci_reinit(struct xhci_hcd *xhci, struct pci_dev *pdev)
+{
+	/*
+	 * TODO: Implement finding debug ports later.
+	 * TODO: see if there are any quirks that need to be added to handle
+	 * new extended capabilities.
+	 */
+
+	/* PCI Memory-Write-Invalidate cycle support is optional (uncommon) */
+	if (!pci_set_mwi(pdev))
+		xhci_dbg(xhci, "MWI active\n");
+
+	xhci_dbg(xhci, "Finished xhci_pci_reinit\n");
+	return 0;
+}
+
+/* called during probe() after chip reset completes */
+static int xhci_pci_setup(struct usb_hcd *hcd)
+{
+	struct xhci_hcd		*xhci = hcd_to_xhci(hcd);
+	struct pci_dev		*pdev = to_pci_dev(hcd->self.controller);
+	int			retval;
+
+	xhci->cap_regs = hcd->regs;
+	xhci->op_regs = hcd->regs +
+		HC_LENGTH(xhci_readl(xhci, &xhci->cap_regs->hc_capbase));
+	xhci->run_regs = hcd->regs +
+		(xhci_readl(xhci, &xhci->cap_regs->run_regs_off) & RTSOFF_MASK);
+	/* Cache read-only capability registers */
+	xhci->hcs_params1 = xhci_readl(xhci, &xhci->cap_regs->hcs_params1);
+	xhci->hcs_params2 = xhci_readl(xhci, &xhci->cap_regs->hcs_params2);
+	xhci->hcs_params3 = xhci_readl(xhci, &xhci->cap_regs->hcs_params3);
+	xhci->hcc_params = xhci_readl(xhci, &xhci->cap_regs->hcc_params);
+	xhci_print_registers(xhci);
+
+	/* Make sure the HC is halted. */
+	retval = xhci_halt(xhci);
+	if (retval)
+		return retval;
+
+	xhci_dbg(xhci, "Resetting HCD\n");
+	/* Reset the internal HC memory state and registers. */
+	retval = xhci_reset(xhci);
+	if (retval)
+		return retval;
+	xhci_dbg(xhci, "Reset complete\n");
+
+	xhci_dbg(xhci, "Calling HCD init\n");
+	/* Initialize HCD and host controller data structures. */
+	retval = xhci_init(hcd);
+	if (retval)
+		return retval;
+	xhci_dbg(xhci, "Called HCD init\n");
+
+	pci_read_config_byte(pdev, XHCI_SBRN_OFFSET, &xhci->sbrn);
+	xhci_dbg(xhci, "Got SBRN %u\n", (unsigned int) xhci->sbrn);
+
+	/* Find any debug ports */
+	return xhci_pci_reinit(xhci, pdev);
+}
+
+static const struct hc_driver xhci_pci_hc_driver = {
+	.description =		hcd_name,
+	.product_desc =		"xHCI Host Controller",
+	.hcd_priv_size =	sizeof(struct xhci_hcd),
+
+	/*
+	 * generic hardware linkage
+	 */
+	.flags =		HCD_MEMORY | HCD_USB3,
+
+	/*
+	 * basic lifecycle operations
+	 */
+	.reset =		xhci_pci_setup,
+	.start =		xhci_run,
+	/* suspend and resume implemented later */
+	.stop =			xhci_stop,
+	.shutdown =		xhci_shutdown,
+
+	/*
+	 * scheduling support
+	 */
+	.get_frame_number =	xhci_get_frame,
+
+	/* Implement root hub support later. */
+};
+
+/*-------------------------------------------------------------------------*/
+
+/* PCI driver selection metadata; PCI hotplugging uses this */
+static const struct pci_device_id pci_ids[] = { {
+	/* handle any USB 3.0 xHCI controller */
+	PCI_DEVICE_CLASS(PCI_CLASS_SERIAL_USB_XHCI, ~0),
+	.driver_data =	(unsigned long) &xhci_pci_hc_driver,
+	},
+	{ /* end: all zeroes */ }
+};
+MODULE_DEVICE_TABLE(pci, pci_ids);
+
+/* pci driver glue; this is a "new style" PCI driver module */
+static struct pci_driver xhci_pci_driver = {
+	.name =		(char *) hcd_name,
+	.id_table =	pci_ids,
+
+	.probe =	usb_hcd_pci_probe,
+	.remove =	usb_hcd_pci_remove,
+	/* suspend and resume implemented later */
+
+	.shutdown = 	usb_hcd_pci_shutdown,
+};
+
+int xhci_register_pci()
+{
+	return pci_register_driver(&xhci_pci_driver);
+}
+
+void xhci_unregister_pci()
+{
+	pci_unregister_driver(&xhci_pci_driver);
+}
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index a4d44aad069..59fae2e5ea5 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -32,6 +32,9 @@
 /* xHCI PCI Configuration Registers */
 #define XHCI_SBRN_OFFSET	(0x60)
 
+/* Max number of USB devices for any host controller - limit in section 6.1 */
+#define MAX_HC_SLOTS		256
+
 /*
  * xHCI register interface.
  * This corresponds to the eXtensible Host Controller Interface (xHCI)
@@ -359,10 +362,35 @@ struct intr_reg {
 	u32	erst_dequeue[2];
 } __attribute__ ((packed));
 
+/* irq_pending bitmasks */
 #define	ER_IRQ_PENDING(p)	((p) & 0x1)
-#define	ER_IRQ_ENABLE(p)	((p) | 0x2)
+/* bits 2:31 need to be preserved */
+#define	ER_IRQ_CLEAR(p)		((p) & 0xfffffffe)
+#define	ER_IRQ_ENABLE(p)	((ER_IRQ_CLEAR(p)) | 0x2)
+#define	ER_IRQ_DISABLE(p)	((ER_IRQ_CLEAR(p)) & ~(0x2))
+
+/* irq_control bitmasks */
+/* Minimum interval between interrupts (in 250ns intervals).  The interval
+ * between interrupts will be longer if there are no events on the event ring.
+ * Default is 4000 (1 ms).
+ */
+#define ER_IRQ_INTERVAL_MASK	(0xffff)
+/* Counter used to count down the time to the next interrupt - HW use only */
+#define ER_IRQ_COUNTER_MASK	(0xffff << 16)
+
+/* erst_size bitmasks */
 /* Preserve bits 16:31 of erst_size */
-#define	ERST_SIZE_MASK	(0xffff<<16)
+#define	ERST_SIZE_MASK		(0xffff << 16)
+
+/* erst_dequeue bitmasks */
+/* Dequeue ERST Segment Index (DESI) - Segment number (or alias)
+ * where the current dequeue pointer lies.  This is an optional HW hint.
+ */
+#define ERST_DESI_MASK		(0x7)
+/* Event Handler Busy (EHB) - is the event ring scheduled to be serviced by
+ * a work queue (or delayed service routine)?
+ */
+#define ERST_EHB		(1 << 3)
 
 /**
  * struct xhci_run_regs
@@ -386,6 +414,8 @@ struct xhci_hcd {
 	struct xhci_cap_regs __iomem *cap_regs;
 	struct xhci_op_regs __iomem *op_regs;
 	struct xhci_run_regs __iomem *run_regs;
+	/* Our HCD's current interrupter register set */
+	struct	intr_reg __iomem *ir_set;
 
 	/* Cached register copies of read-only HC data */
 	__u32		hcs_params1;
@@ -404,7 +434,13 @@ struct xhci_hcd {
 	u8		isoc_threshold;
 	int		event_ring_max;
 	int		addr_64;
+	/* 4KB min, 128MB max */
 	int		page_size;
+	/* Valid values are 12 to 20, inclusive */
+	int		page_shift;
+	/* only one MSI vector for now, but might need more later */
+	int		msix_count;
+	struct msix_entry	*msix_entries;
 };
 
 /* convert between an HCD pointer and the corresponding EHCI_HCD */
@@ -449,4 +485,27 @@ static inline void xhci_writel(const struct xhci_hcd *xhci,
 	writel(val, regs);
 }
 
+/* xHCI debugging */
+void xhci_print_ir_set(struct xhci_hcd *xhci, struct intr_reg *ir_set, int set_num);
+void xhci_print_registers(struct xhci_hcd *xhci);
+
+/* xHCI memory managment */
+void xhci_mem_cleanup(struct xhci_hcd *xhci);
+int xhci_mem_init(struct xhci_hcd *xhci, gfp_t flags);
+
+#ifdef CONFIG_PCI
+/* xHCI PCI glue */
+int xhci_register_pci(void);
+void xhci_unregister_pci(void);
+#endif
+
+/* xHCI host controller glue */
+int xhci_halt(struct xhci_hcd *xhci);
+int xhci_reset(struct xhci_hcd *xhci);
+int xhci_init(struct usb_hcd *hcd);
+int xhci_run(struct usb_hcd *hcd);
+void xhci_stop(struct usb_hcd *hcd);
+void xhci_shutdown(struct usb_hcd *hcd);
+int xhci_get_frame(struct usb_hcd *hcd);
+
 #endif /* __LINUX_XHCI_HCD_H */