/*
 * This file contains code to reset and initialize USB host controllers.
 * Some of it includes work-arounds for PCI hardware and BIOS quirks.
 * It may need to run early during booting -- before USB would normally
 * initialize -- to ensure that Linux doesn't use any legacy modes.
 *
 *  Copyright (c) 1999 Martin Mares <mj@ucw.cz>
 *  (and others)
 */

#include <linux/config.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/pci.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/acpi.h>


#define UHCI_USBLEGSUP		0xc0		/* legacy support */
#define UHCI_USBCMD		0		/* command register */
#define UHCI_USBINTR		4		/* interrupt register */
#define UHCI_USBLEGSUP_RWC	0x8f00		/* the R/WC bits */
#define UHCI_USBLEGSUP_RO	0x5040		/* R/O and reserved bits */
#define UHCI_USBCMD_RUN		0x0001		/* RUN/STOP bit */
#define UHCI_USBCMD_HCRESET	0x0002		/* Host Controller reset */
#define UHCI_USBCMD_EGSM	0x0008		/* Global Suspend Mode */
#define UHCI_USBCMD_CONFIGURE	0x0040		/* Config Flag */
#define UHCI_USBINTR_RESUME	0x0002		/* Resume interrupt enable */

#define OHCI_CONTROL		0x04
#define OHCI_CMDSTATUS		0x08
#define OHCI_INTRSTATUS		0x0c
#define OHCI_INTRENABLE		0x10
#define OHCI_INTRDISABLE	0x14
#define OHCI_OCR		(1 << 3)	/* ownership change request */
#define OHCI_CTRL_RWC		(1 << 9)	/* remote wakeup connected */
#define OHCI_CTRL_IR		(1 << 8)	/* interrupt routing */
#define OHCI_INTR_OC		(1 << 30)	/* ownership change */

#define EHCI_HCC_PARAMS		0x08		/* extended capabilities */
#define EHCI_USBCMD		0		/* command register */
#define EHCI_USBCMD_RUN		(1 << 0)	/* RUN/STOP bit */
#define EHCI_USBSTS		4		/* status register */
#define EHCI_USBSTS_HALTED	(1 << 12)	/* HCHalted bit */
#define EHCI_USBINTR		8		/* interrupt register */
#define EHCI_USBLEGSUP		0		/* legacy support register */
#define EHCI_USBLEGSUP_BIOS	(1 << 16)	/* BIOS semaphore */
#define EHCI_USBLEGSUP_OS	(1 << 24)	/* OS semaphore */
#define EHCI_USBLEGCTLSTS	4		/* legacy control/status */
#define EHCI_USBLEGCTLSTS_SOOE	(1 << 13)	/* SMI on ownership change */


/*
 * Make sure the controller is completely inactive, unable to
 * generate interrupts or do DMA.
 */
void uhci_reset_hc(struct pci_dev *pdev, unsigned long base)
{
	/* Turn off PIRQ enable and SMI enable.  (This also turns off the
	 * BIOS's USB Legacy Support.)  Turn off all the R/WC bits too.
	 */
	pci_write_config_word(pdev, UHCI_USBLEGSUP, UHCI_USBLEGSUP_RWC);

	/* Reset the HC - this will force us to get a
	 * new notification of any already connected
	 * ports due to the virtual disconnect that it
	 * implies.
	 */
	outw(UHCI_USBCMD_HCRESET, base + UHCI_USBCMD);
	mb();
	udelay(5);
	if (inw(base + UHCI_USBCMD) & UHCI_USBCMD_HCRESET)
		dev_warn(&pdev->dev, "HCRESET not completed yet!\n");

	/* Just to be safe, disable interrupt requests and
	 * make sure the controller is stopped.
	 */
	outw(0, base + UHCI_USBINTR);
	outw(0, base + UHCI_USBCMD);
}
EXPORT_SYMBOL_GPL(uhci_reset_hc);

/*
 * Initialize a controller that was newly discovered or has just been
 * resumed.  In either case we can't be sure of its previous state.
 *
 * Returns: 1 if the controller was reset, 0 otherwise.
 */
int uhci_check_and_reset_hc(struct pci_dev *pdev, unsigned long base)
{
	u16 legsup;
	unsigned int cmd, intr;

	/*
	 * When restarting a suspended controller, we expect all the
	 * settings to be the same as we left them:
	 *
	 *	PIRQ and SMI disabled, no R/W bits set in USBLEGSUP;
	 *	Controller is stopped and configured with EGSM set;
	 *	No interrupts enabled except possibly Resume Detect.
	 *
	 * If any of these conditions are violated we do a complete reset.
	 */
	pci_read_config_word(pdev, UHCI_USBLEGSUP, &legsup);
	if (legsup & ~(UHCI_USBLEGSUP_RO | UHCI_USBLEGSUP_RWC)) {
		dev_dbg(&pdev->dev, "%s: legsup = 0x%04x\n",
				__FUNCTION__, legsup);
		goto reset_needed;
	}

	cmd = inw(base + UHCI_USBCMD);
	if ((cmd & UHCI_USBCMD_RUN) || !(cmd & UHCI_USBCMD_CONFIGURE) ||
			!(cmd & UHCI_USBCMD_EGSM)) {
		dev_dbg(&pdev->dev, "%s: cmd = 0x%04x\n",
				__FUNCTION__, cmd);
		goto reset_needed;
	}

	intr = inw(base + UHCI_USBINTR);
	if (intr & (~UHCI_USBINTR_RESUME)) {
		dev_dbg(&pdev->dev, "%s: intr = 0x%04x\n",
				__FUNCTION__, intr);
		goto reset_needed;
	}
	return 0;

reset_needed:
	dev_dbg(&pdev->dev, "Performing full reset\n");
	uhci_reset_hc(pdev, base);
	return 1;
}
EXPORT_SYMBOL_GPL(uhci_check_and_reset_hc);

static inline int io_type_enabled(struct pci_dev *pdev, unsigned int mask)
{
	u16 cmd;
	return !pci_read_config_word(pdev, PCI_COMMAND, &cmd) && (cmd & mask);
}

#define pio_enabled(dev) io_type_enabled(dev, PCI_COMMAND_IO)
#define mmio_enabled(dev) io_type_enabled(dev, PCI_COMMAND_MEMORY)

static void __devinit quirk_usb_handoff_uhci(struct pci_dev *pdev)
{
	unsigned long base = 0;
	int i;

	if (!pio_enabled(pdev))
		return;

	for (i = 0; i < PCI_ROM_RESOURCE; i++)
		if ((pci_resource_flags(pdev, i) & IORESOURCE_IO)) {
			base = pci_resource_start(pdev, i);
			break;
		}

	if (base)
		uhci_check_and_reset_hc(pdev, base);
}

static int __devinit mmio_resource_enabled(struct pci_dev *pdev, int idx)
{
	return pci_resource_start(pdev, idx) && mmio_enabled(pdev);
}

static void __devinit quirk_usb_handoff_ohci(struct pci_dev *pdev)
{
	void __iomem *base;
	int wait_time;
	u32 control;

	if (!mmio_resource_enabled(pdev, 0))
		return;

	base = ioremap_nocache(pci_resource_start(pdev, 0),
				     pci_resource_len(pdev, 0));
	if (base == NULL) return;

/* On PA-RISC, PDC can leave IR set incorrectly; ignore it there. */
#ifndef __hppa__
	control = readl(base + OHCI_CONTROL);
	if (control & OHCI_CTRL_IR) {
		wait_time = 500; /* arbitrary; 5 seconds */
		writel(OHCI_INTR_OC, base + OHCI_INTRENABLE);
		writel(OHCI_OCR, base + OHCI_CMDSTATUS);
		while (wait_time > 0 &&
				readl(base + OHCI_CONTROL) & OHCI_CTRL_IR) {
			wait_time -= 10;
			msleep(10);
		}
		if (wait_time <= 0)
			printk(KERN_WARNING "%s %s: BIOS handoff "
					"failed (BIOS bug ?) %08x\n",
					pdev->dev.bus_id, "OHCI",
					readl(base + OHCI_CONTROL));

		/* reset controller, preserving RWC */
		writel(control & OHCI_CTRL_RWC, base + OHCI_CONTROL);
	}
#endif

	/*
	 * disable interrupts
	 */
	writel(~(u32)0, base + OHCI_INTRDISABLE);
	writel(~(u32)0, base + OHCI_INTRSTATUS);

	iounmap(base);
}

static void __devinit quirk_usb_disable_ehci(struct pci_dev *pdev)
{
	int wait_time, delta;
	void __iomem *base, *op_reg_base;
	u32	hcc_params, val;
	u8	offset, cap_length;
	int	count = 256/4;

	if (!mmio_resource_enabled(pdev, 0))
		return;

	base = ioremap_nocache(pci_resource_start(pdev, 0),
				pci_resource_len(pdev, 0));
	if (base == NULL) return;

	cap_length = readb(base);
	op_reg_base = base + cap_length;

	/* EHCI 0.96 and later may have "extended capabilities"
	 * spec section 5.1 explains the bios handoff, e.g. for
	 * booting from USB disk or using a usb keyboard
	 */
	hcc_params = readl(base + EHCI_HCC_PARAMS);
	offset = (hcc_params >> 8) & 0xff;
	while (offset && count--) {
		u32		cap;
		int		msec;

		pci_read_config_dword(pdev, offset, &cap);
		switch (cap & 0xff) {
		case 1:			/* BIOS/SMM/... handoff support */
			if ((cap & EHCI_USBLEGSUP_BIOS)) {
				pr_debug("%s %s: BIOS handoff\n",
						pdev->dev.bus_id, "EHCI");

#if 0
/* aleksey_gorelov@phoenix.com reports that some systems need SMI forced on,
 * but that seems dubious in general (the BIOS left it off intentionally)
 * and is known to prevent some systems from booting.  so we won't do this
 * unless maybe we can determine when we're on a system that needs SMI forced.
 */
				/* BIOS workaround (?): be sure the
				 * pre-Linux code receives the SMI
				 */
				pci_read_config_dword(pdev,
						offset + EHCI_USBLEGCTLSTS,
						&val);
				pci_write_config_dword(pdev,
						offset + EHCI_USBLEGCTLSTS,
						val | EHCI_USBLEGCTLSTS_SOOE);
#endif

				/* some systems get upset if this semaphore is
				 * set for any other reason than forcing a BIOS
				 * handoff..
				 */
				pci_write_config_byte(pdev, offset + 3, 1);
			}

			/* if boot firmware now owns EHCI, spin till
			 * it hands it over.
			 */
			msec = 5000;
			while ((cap & EHCI_USBLEGSUP_BIOS) && (msec > 0)) {
				msleep(10);
				msec -= 10;
				pci_read_config_dword(pdev, offset, &cap);
			}

			if (cap & EHCI_USBLEGSUP_BIOS) {
				/* well, possibly buggy BIOS... try to shut
				 * it down, and hope nothing goes too wrong
				 */
				printk(KERN_WARNING "%s %s: BIOS handoff "
						"failed (BIOS bug ?) %08x\n",
					pdev->dev.bus_id, "EHCI", cap);
				pci_write_config_byte(pdev, offset + 2, 0);
			}

			/* just in case, always disable EHCI SMIs */
			pci_write_config_dword(pdev,
					offset + EHCI_USBLEGCTLSTS,
					0);
			break;
		case 0:			/* illegal reserved capability */
			cap = 0;
			/* FALLTHROUGH */
		default:
			printk(KERN_WARNING "%s %s: unrecognized "
					"capability %02x\n",
					pdev->dev.bus_id, "EHCI",
					cap & 0xff);
			break;
		}
		offset = (cap >> 8) & 0xff;
	}
	if (!count)
		printk(KERN_DEBUG "%s %s: capability loop?\n",
				pdev->dev.bus_id, "EHCI");

	/*
	 * halt EHCI & disable its interrupts in any case
	 */
	val = readl(op_reg_base + EHCI_USBSTS);
	if ((val & EHCI_USBSTS_HALTED) == 0) {
		val = readl(op_reg_base + EHCI_USBCMD);
		val &= ~EHCI_USBCMD_RUN;
		writel(val, op_reg_base + EHCI_USBCMD);

		wait_time = 2000;
		delta = 100;
		do {
			writel(0x3f, op_reg_base + EHCI_USBSTS);
			udelay(delta);
			wait_time -= delta;
			val = readl(op_reg_base + EHCI_USBSTS);
			if ((val == ~(u32)0) || (val & EHCI_USBSTS_HALTED)) {
				break;
			}
		} while (wait_time > 0);
	}
	writel(0, op_reg_base + EHCI_USBINTR);
	writel(0x3f, op_reg_base + EHCI_USBSTS);

	iounmap(base);

	return;
}


static void __devinit quirk_usb_early_handoff(struct pci_dev *pdev)
{
	if (pdev->class == PCI_CLASS_SERIAL_USB_UHCI)
		quirk_usb_handoff_uhci(pdev);
	else if (pdev->class == PCI_CLASS_SERIAL_USB_OHCI)
		quirk_usb_handoff_ohci(pdev);
	else if (pdev->class == PCI_CLASS_SERIAL_USB_EHCI)
		quirk_usb_disable_ehci(pdev);
}
DECLARE_PCI_FIXUP_FINAL(PCI_ANY_ID, PCI_ANY_ID, quirk_usb_early_handoff);