/*
 * 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.
 */
/* Up to 16 microframes to halt an HC - one microframe is 125 microsectonds */
#define XHCI_MAX_HALT_USEC      (16*125)
/* HC not running - set to 1 when run/stop bit is cleared. */
#define XHCI_STS_HALT           (1<<0)

/* HCCPARAMS offset from PCI base address */
#define XHCI_HCC_PARAMS_OFFSET  0x10
/* HCCPARAMS contains the first extended capability pointer */
#define XHCI_HCC_EXT_CAPS(p)    (((p)>>16)&0xffff)

/* Command and Status registers offset from the Operational Registers address */
#define XHCI_CMD_OFFSET         0x00
#define XHCI_STS_OFFSET         0x04

#define XHCI_MAX_EXT_CAPS               50

/* Capability Register */
/* bits 7:0 - how long is the Capabilities register */
#define XHCI_HC_LENGTH(p)       (((p)>>00)&0x00ff)

/* Extended capability register fields */
#define XHCI_EXT_CAPS_ID(p)     (((p)>>0)&0xff)
#define XHCI_EXT_CAPS_NEXT(p)   (((p)>>8)&0xff)
#define XHCI_EXT_CAPS_VAL(p)    ((p)>>16)
/* Extended capability IDs - ID 0 reserved */
#define XHCI_EXT_CAPS_LEGACY    1
#define XHCI_EXT_CAPS_PROTOCOL  2
#define XHCI_EXT_CAPS_PM        3
#define XHCI_EXT_CAPS_VIRT      4
#define XHCI_EXT_CAPS_ROUTE     5
/* IDs 6-9 reserved */
#define XHCI_EXT_CAPS_DEBUG     10
/* USB Legacy Support Capability - section 7.1.1 */
#define XHCI_HC_BIOS_OWNED      (1 << 16)
#define XHCI_HC_OS_OWNED        (1 << 24)

/* USB Legacy Support Capability - section 7.1.1 */
/* Add this offset, plus the value of xECP in HCCPARAMS to the base address */
#define XHCI_LEGACY_SUPPORT_OFFSET      (0x00)

/* USB Legacy Support Control and Status Register  - section 7.1.2 */
/* Add this offset, plus the value of xECP in HCCPARAMS to the base address */
#define XHCI_LEGACY_CONTROL_OFFSET      (0x04)
/* bits 1:2, 5:12, and 17:19 need to be preserved; bits 21:28 should be zero */
#define XHCI_LEGACY_DISABLE_SMI         ((0x3 << 1) + (0xff << 5) + (0x7 << 17))

/* command register values to disable interrupts and halt the HC */
/* start/stop HC execution - do not write unless HC is halted*/
#define XHCI_CMD_RUN            (1 << 0)
/* Event Interrupt Enable - get irq when EINT bit is set in USBSTS register */
#define XHCI_CMD_EIE            (1 << 2)
/* Host System Error Interrupt Enable - get irq when HSEIE bit set in USBSTS */
#define XHCI_CMD_HSEIE          (1 << 3)
/* Enable Wrap Event - '1' means xHC generates an event when MFINDEX wraps. */
#define XHCI_CMD_EWE            (1 << 10)

#define XHCI_IRQS               (XHCI_CMD_EIE | XHCI_CMD_HSEIE | XHCI_CMD_EWE)

/* true: Controller Not Ready to accept doorbell or op reg writes after reset */
#define XHCI_STS_CNR            (1 << 11)

#include <linux/io.h>

/**
 * Return the next extended capability pointer register.
 *
 * @base        PCI register base address.
 *
 * @ext_offset  Offset of the 32-bit register that contains the extended
 * capabilites pointer.  If searching for the first extended capability, pass
 * in XHCI_HCC_PARAMS_OFFSET.  If searching for the next extended capability,
 * pass in the offset of the current extended capability register.
 *
 * Returns 0 if there is no next extended capability register or returns the register offset
 * from the PCI registers base address.
 */
static inline int xhci_find_next_cap_offset(void __iomem *base, int ext_offset)
{
        u32 next;

        next = readl(base + ext_offset);

        if (ext_offset == XHCI_HCC_PARAMS_OFFSET)
                /* Find the first extended capability */
                next = XHCI_HCC_EXT_CAPS(next);
        else
                /* Find the next extended capability */
                next = XHCI_EXT_CAPS_NEXT(next);
        if (!next)
                return 0;
        /*
         * Address calculation from offset of extended capabilities
         * (or HCCPARAMS) register - see section 5.3.6 and section 7.
         */
        return ext_offset + (next << 2);
}

/**
 * Find the offset of the extended capabilities with capability ID id.
 *
 * @base PCI MMIO registers base address.
 * @ext_offset Offset from base of the first extended capability to look at,
 *              or the address of HCCPARAMS.
 * @id Extended capability ID to search for.
 *
 * This uses an arbitrary limit of XHCI_MAX_EXT_CAPS extended capabilities
 * to make sure that the list doesn't contain a loop.
 */
static inline int xhci_find_ext_cap_by_id(void __iomem *base, int ext_offset, int id)
{
        u32 val;
        int limit = XHCI_MAX_EXT_CAPS;

        while (ext_offset && limit > 0) {
                val = readl(base + ext_offset);
                if (XHCI_EXT_CAPS_ID(val) == id)
                        break;
                ext_offset = xhci_find_next_cap_offset(base, ext_offset);
                limit--;
        }
        if (limit > 0)
                return ext_offset;
        return 0;
}