/*
 *      PCI Bus Services, see include/linux/pci.h for further explanation.
 *
 *      Copyright 1993 -- 1997 Drew Eckhardt, Frederic Potter,
 *      David Mosberger-Tang
 *
 *      Copyright 1997 -- 2000 Martin Mares <mj@ucw.cz>
 */

#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/pci.h>
#include <linux/pm.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/log2.h>
#include <linux/pci-aspm.h>
#include <linux/pm_wakeup.h>
#include <linux/interrupt.h>
#include <asm/dma.h>    /* isa_dma_bridge_buggy */
#include <linux/device.h>
#include <asm/setup.h>
#include "pci.h"

unsigned int pci_pm_d3_delay = PCI_PM_D3_WAIT;

#ifdef CONFIG_PCI_DOMAINS
int pci_domains_supported = 1;
#endif

#define DEFAULT_CARDBUS_IO_SIZE         (256)
#define DEFAULT_CARDBUS_MEM_SIZE        (64*1024*1024)
/* pci=cbmemsize=nnM,cbiosize=nn can override this */
unsigned long pci_cardbus_io_size = DEFAULT_CARDBUS_IO_SIZE;
unsigned long pci_cardbus_mem_size = DEFAULT_CARDBUS_MEM_SIZE;

/**
 * pci_bus_max_busnr - returns maximum PCI bus number of given bus' children
 * @bus: pointer to PCI bus structure to search
 *
 * Given a PCI bus, returns the highest PCI bus number present in the set
 * including the given PCI bus and its list of child PCI buses.
 */
unsigned char pci_bus_max_busnr(struct pci_bus* bus)
{
        struct list_head *tmp;
        unsigned char max, n;

        max = bus->subordinate;
        list_for_each(tmp, &bus->children) {
                n = pci_bus_max_busnr(pci_bus_b(tmp));
                if(n > max)
                        max = n;
        }
        return max;
}
EXPORT_SYMBOL_GPL(pci_bus_max_busnr);

#ifdef CONFIG_HAS_IOMEM
void __iomem *pci_ioremap_bar(struct pci_dev *pdev, int bar)
{
        /*
         * Make sure the BAR is actually a memory resource, not an IO resource
         */
        if (!(pci_resource_flags(pdev, bar) & IORESOURCE_MEM)) {
                WARN_ON(1);
                return NULL;
        }
        return ioremap_nocache(pci_resource_start(pdev, bar),
                                     pci_resource_len(pdev, bar));
}
EXPORT_SYMBOL_GPL(pci_ioremap_bar);
#endif

#if 0
/**
 * pci_max_busnr - returns maximum PCI bus number
 *
 * Returns the highest PCI bus number present in the system global list of
 * PCI buses.
 */
unsigned char __devinit
pci_max_busnr(void)
{
        struct pci_bus *bus = NULL;
        unsigned char max, n;

        max = 0;
        while ((bus = pci_find_next_bus(bus)) != NULL) {
                n = pci_bus_max_busnr(bus);
                if(n > max)
                        max = n;
        }
        return max;
}

#endif  /*  0  */

#define PCI_FIND_CAP_TTL        48

static int __pci_find_next_cap_ttl(struct pci_bus *bus, unsigned int devfn,
                                   u8 pos, int cap, int *ttl)
{
        u8 id;

        while ((*ttl)--) {
                pci_bus_read_config_byte(bus, devfn, pos, &pos);
                if (pos < 0x40)
                        break;
                pos &= ~3;
                pci_bus_read_config_byte(bus, devfn, pos + PCI_CAP_LIST_ID,
                                         &id);
                if (id == 0xff)
                        break;
                if (id == cap)
                        return pos;
                pos += PCI_CAP_LIST_NEXT;
        }
        return 0;
}

static int __pci_find_next_cap(struct pci_bus *bus, unsigned int devfn,
                               u8 pos, int cap)
{
        int ttl = PCI_FIND_CAP_TTL;

        return __pci_find_next_cap_ttl(bus, devfn, pos, cap, &ttl);
}

int pci_find_next_capability(struct pci_dev *dev, u8 pos, int cap)
{
        return __pci_find_next_cap(dev->bus, dev->devfn,
                                   pos + PCI_CAP_LIST_NEXT, cap);
}
EXPORT_SYMBOL_GPL(pci_find_next_capability);

static int __pci_bus_find_cap_start(struct pci_bus *bus,
                                    unsigned int devfn, u8 hdr_type)
{
        u16 status;

        pci_bus_read_config_word(bus, devfn, PCI_STATUS, &status);
        if (!(status & PCI_STATUS_CAP_LIST))
                return 0;

        switch (hdr_type) {
        case PCI_HEADER_TYPE_NORMAL:
        case PCI_HEADER_TYPE_BRIDGE:
                return PCI_CAPABILITY_LIST;
        case PCI_HEADER_TYPE_CARDBUS:
                return PCI_CB_CAPABILITY_LIST;
        default:
                return 0;
        }

        return 0;
}

/**
 * pci_find_capability - query for devices' capabilities 
 * @dev: PCI device to query
 * @cap: capability code
 *
 * Tell if a device supports a given PCI capability.
 * Returns the address of the requested capability structure within the
 * device's PCI configuration space or 0 in case the device does not
 * support it.  Possible values for @cap:
 *
 *  %PCI_CAP_ID_PM           Power Management 
 *  %PCI_CAP_ID_AGP          Accelerated Graphics Port 
 *  %PCI_CAP_ID_VPD          Vital Product Data 
 *  %PCI_CAP_ID_SLOTID       Slot Identification 
 *  %PCI_CAP_ID_MSI          Message Signalled Interrupts
 *  %PCI_CAP_ID_CHSWP        CompactPCI HotSwap 
 *  %PCI_CAP_ID_PCIX         PCI-X
 *  %PCI_CAP_ID_EXP          PCI Express
 */
int pci_find_capability(struct pci_dev *dev, int cap)
{
        int pos;

        pos = __pci_bus_find_cap_start(dev->bus, dev->devfn, dev->hdr_type);
        if (pos)
                pos = __pci_find_next_cap(dev->bus, dev->devfn, pos, cap);

        return pos;
}

/**
 * pci_bus_find_capability - query for devices' capabilities 
 * @bus:   the PCI bus to query
 * @devfn: PCI device to query
 * @cap:   capability code
 *
 * Like pci_find_capability() but works for pci devices that do not have a
 * pci_dev structure set up yet. 
 *
 * Returns the address of the requested capability structure within the
 * device's PCI configuration space or 0 in case the device does not
 * support it.
 */
int pci_bus_find_capability(struct pci_bus *bus, unsigned int devfn, int cap)
{
        int pos;
        u8 hdr_type;

        pci_bus_read_config_byte(bus, devfn, PCI_HEADER_TYPE, &hdr_type);

        pos = __pci_bus_find_cap_start(bus, devfn, hdr_type & 0x7f);
        if (pos)
                pos = __pci_find_next_cap(bus, devfn, pos, cap);

        return pos;
}

/**
 * pci_find_ext_capability - Find an extended capability
 * @dev: PCI device to query
 * @cap: capability code
 *
 * Returns the address of the requested extended capability structure
 * within the device's PCI configuration space or 0 if the device does
 * not support it.  Possible values for @cap:
 *
 *  %PCI_EXT_CAP_ID_ERR         Advanced Error Reporting
 *  %PCI_EXT_CAP_ID_VC          Virtual Channel
 *  %PCI_EXT_CAP_ID_DSN         Device Serial Number
 *  %PCI_EXT_CAP_ID_PWR         Power Budgeting
 */
int pci_find_ext_capability(struct pci_dev *dev, int cap)
{
        u32 header;
        int ttl;
        int pos = PCI_CFG_SPACE_SIZE;

        /* minimum 8 bytes per capability */
        ttl = (PCI_CFG_SPACE_EXP_SIZE - PCI_CFG_SPACE_SIZE) / 8;

        if (dev->cfg_size <= PCI_CFG_SPACE_SIZE)
                return 0;

        if (pci_read_config_dword(dev, pos, &header) != PCIBIOS_SUCCESSFUL)
                return 0;

        /*
         * If we have no capabilities, this is indicated by cap ID,
         * cap version and next pointer all being 0.
         */
        if (header == 0)
                return 0;

        while (ttl-- > 0) {
                if (PCI_EXT_CAP_ID(header) == cap)
                        return pos;

                pos = PCI_EXT_CAP_NEXT(header);
                if (pos < PCI_CFG_SPACE_SIZE)
                        break;

                if (pci_read_config_dword(dev, pos, &header) != PCIBIOS_SUCCESSFUL)
                        break;
        }

        return 0;
}
EXPORT_SYMBOL_GPL(pci_find_ext_capability);

static int __pci_find_next_ht_cap(struct pci_dev *dev, int pos, int ht_cap)
{
        int rc, ttl = PCI_FIND_CAP_TTL;
        u8 cap, mask;

        if (ht_cap == HT_CAPTYPE_SLAVE || ht_cap == HT_CAPTYPE_HOST)
                mask = HT_3BIT_CAP_MASK;
        else
                mask = HT_5BIT_CAP_MASK;

        pos = __pci_find_next_cap_ttl(dev->bus, dev->devfn, pos,
                                      PCI_CAP_ID_HT, &ttl);
        while (pos) {
                rc = pci_read_config_byte(dev, pos + 3, &cap);
                if (rc != PCIBIOS_SUCCESSFUL)
                        return 0;

                if ((cap & mask) == ht_cap)
                        return pos;

                pos = __pci_find_next_cap_ttl(dev->bus, dev->devfn,
                                              pos + PCI_CAP_LIST_NEXT,
                                              PCI_CAP_ID_HT, &ttl);
        }

        return 0;
}
/**
 * pci_find_next_ht_capability - query a device's Hypertransport capabilities
 * @dev: PCI device to query
 * @pos: Position from which to continue searching
 * @ht_cap: Hypertransport capability code
 *
 * To be used in conjunction with pci_find_ht_capability() to search for
 * all capabilities matching @ht_cap. @pos should always be a value returned
 * from pci_find_ht_capability().
 *
 * NB. To be 100% safe against broken PCI devices, the caller should take
 * steps to avoid an infinite loop.
 */
int pci_find_next_ht_capability(struct pci_dev *dev, int pos, int ht_cap)
{
        return __pci_find_next_ht_cap(dev, pos + PCI_CAP_LIST_NEXT, ht_cap);
}
EXPORT_SYMBOL_GPL(pci_find_next_ht_capability);

/**
 * pci_find_ht_capability - query a device's Hypertransport capabilities
 * @dev: PCI device to query
 * @ht_cap: Hypertransport capability code
 *
 * Tell if a device supports a given Hypertransport capability.
 * Returns an address within the device's PCI configuration space
 * or 0 in case the device does not support the request capability.
 * The address points to the PCI capability, of type PCI_CAP_ID_HT,
 * which has a Hypertransport capability matching @ht_cap.
 */
int pci_find_ht_capability(struct pci_dev *dev, int ht_cap)
{
        int pos;

        pos = __pci_bus_find_cap_start(dev->bus, dev->devfn, dev->hdr_type);
        if (pos)
                pos = __pci_find_next_ht_cap(dev, pos, ht_cap);

        return pos;
}
EXPORT_SYMBOL_GPL(pci_find_ht_capability);

/**
 * pci_find_parent_resource - return resource region of parent bus of given region
 * @dev: PCI device structure contains resources to be searched
 * @res: child resource record for which parent is sought
 *
 *  For given resource region of given device, return the resource
 *  region of parent bus the given region is contained in or where
 *  it should be allocated from.
 */
struct resource *
pci_find_parent_resource(const struct pci_dev *dev, struct resource *res)
{
        const struct pci_bus *bus = dev->bus;
        int i;
        struct resource *best = NULL;

        for(i = 0; i < PCI_BUS_NUM_RESOURCES; i++) {
                struct resource *r = bus->resource[i];
                if (!r)
                        continue;
                if (res->start && !(res->start >= r->start && res->end <= r->end))
                        continue;       /* Not contained */
                if ((res->flags ^ r->flags) & (IORESOURCE_IO | IORESOURCE_MEM))
                        continue;       /* Wrong type */
                if (!((res->flags ^ r->flags) & IORESOURCE_PREFETCH))
                        return r;       /* Exact match */
                if ((res->flags & IORESOURCE_PREFETCH) && !(r->flags & IORESOURCE_PREFETCH))
                        best = r;       /* Approximating prefetchable by non-prefetchable */
        }
        return best;
}

/**
 * pci_restore_bars - restore a devices BAR values (e.g. after wake-up)
 * @dev: PCI device to have its BARs restored
 *
 * Restore the BAR values for a given device, so as to make it
 * accessible by its driver.
 */
static void
pci_restore_bars(struct pci_dev *dev)
{
        int i;

        for (i = 0; i < PCI_BRIDGE_RESOURCES; i++)
                pci_update_resource(dev, i);
}

static struct pci_platform_pm_ops *pci_platform_pm;

int pci_set_platform_pm(struct pci_platform_pm_ops *ops)
{
        if (!ops->is_manageable || !ops->set_state || !ops->choose_state
            || !ops->sleep_wake || !ops->can_wakeup)
                return -EINVAL;
        pci_platform_pm = ops;
        return 0;
}

static inline bool platform_pci_power_manageable(struct pci_dev *dev)
{
        return pci_platform_pm ? pci_platform_pm->is_manageable(dev) : false;
}

static inline int platform_pci_set_power_state(struct pci_dev *dev,
                                                pci_power_t t)
{
        return pci_platform_pm ? pci_platform_pm->set_state(dev, t) : -ENOSYS;
}

static inline pci_power_t platform_pci_choose_state(struct pci_dev *dev)
{
        return pci_platform_pm ?
                        pci_platform_pm->choose_state(dev) : PCI_POWER_ERROR;
}

static inline bool platform_pci_can_wakeup(struct pci_dev *dev)
{
        return pci_platform_pm ? pci_platform_pm->can_wakeup(dev) : false;
}

static inline int platform_pci_sleep_wake(struct pci_dev *dev, bool enable)
{
        return pci_platform_pm ?
                        pci_platform_pm->sleep_wake(dev, enable) : -ENODEV;
}

/**
 * pci_raw_set_power_state - Use PCI PM registers to set the power state of
 *                           given PCI device
 * @dev: PCI device to handle.
 * @state: PCI power state (D0, D1, D2, D3hot) to put the device into.
 *
 * RETURN VALUE:
 * -EINVAL if the requested state is invalid.
 * -EIO if device does not support PCI PM or its PM capabilities register has a
 * wrong version, or device doesn't support the requested state.
 * 0 if device already is in the requested state.
 * 0 if device's power state has been successfully changed.
 */
static int pci_raw_set_power_state(struct pci_dev *dev, pci_power_t state)
{
        u16 pmcsr;
        bool need_restore = false;

        /* Check if we're already there */
        if (dev->current_state == state)
                return 0;

        if (!dev->pm_cap)
                return -EIO;

        if (state < PCI_D0 || state > PCI_D3hot)
                return -EINVAL;

        /* Validate current state:
         * Can enter D0 from any state, but if we can only go deeper 
         * to sleep if we're already in a low power state
         */
        if (state != PCI_D0 && dev->current_state <= PCI_D3cold
            && dev->current_state > state) {
                dev_err(&dev->dev, "invalid power transition "
                        "(from state %d to %d)\n", dev->current_state, state);
                return -EINVAL;
        }

        /* check if this device supports the desired state */
        if ((state == PCI_D1 && !dev->d1_support)
           || (state == PCI_D2 && !dev->d2_support))
                return -EIO;

        pci_read_config_word(dev, dev->pm_cap + PCI_PM_CTRL, &pmcsr);

        /* If we're (effectively) in D3, force entire word to 0.
         * This doesn't affect PME_Status, disables PME_En, and
         * sets PowerState to 0.
         */
        switch (dev->current_state) {
        case PCI_D0:
        case PCI_D1:
        case PCI_D2:
                pmcsr &= ~PCI_PM_CTRL_STATE_MASK;
                pmcsr |= state;
                break;
        case PCI_D3hot:
        case PCI_D3cold:
        case PCI_UNKNOWN: /* Boot-up */
                if ((pmcsr & PCI_PM_CTRL_STATE_MASK) == PCI_D3hot
                 && !(pmcsr & PCI_PM_CTRL_NO_SOFT_RESET))
                        need_restore = true;
                /* Fall-through: force to D0 */
        default:
                pmcsr = 0;
                break;
        }

        /* enter specified state */
        pci_write_config_word(dev, dev->pm_cap + PCI_PM_CTRL, pmcsr);

        /* Mandatory power management transition delays */
        /* see PCI PM 1.1 5.6.1 table 18 */
        if (state == PCI_D3hot || dev->current_state == PCI_D3hot)
                msleep(pci_pm_d3_delay);
        else if (state == PCI_D2 || dev->current_state == PCI_D2)
                udelay(PCI_PM_D2_DELAY);

        dev->current_state = state;

        /* According to section 5.4.1 of the "PCI BUS POWER MANAGEMENT
         * INTERFACE SPECIFICATION, REV. 1.2", a device transitioning
         * from D3hot to D0 _may_ perform an internal reset, thereby
         * going to "D0 Uninitialized" rather than "D0 Initialized".
         * For example, at least some versions of the 3c905B and the
         * 3c556B exhibit this behaviour.
         *
         * At least some laptop BIOSen (e.g. the Thinkpad T21) leave
         * devices in a D3hot state at boot.  Consequently, we need to
         * restore at least the BARs so that the device will be
         * accessible to its driver.
         */
        if (need_restore)
                pci_restore_bars(dev);

        if (dev->bus->self)
                pcie_aspm_pm_state_change(dev->bus->self);

        return 0;
}

/**
 * pci_update_current_state - Read PCI power state of given device from its
 *                            PCI PM registers and cache it
 * @dev: PCI device to handle.
 * @state: State to cache in case the device doesn't have the PM capability
 */
void pci_update_current_state(struct pci_dev *dev, pci_power_t state)
{
        if (dev->pm_cap) {
                u16 pmcsr;

                pci_read_config_word(dev, dev->pm_cap + PCI_PM_CTRL, &pmcsr);
                dev->current_state = (pmcsr & PCI_PM_CTRL_STATE_MASK);
        } else {
                dev->current_state = state;
        }
}

/**
 * pci_platform_power_transition - Use platform to change device power state
 * @dev: PCI device to handle.
 * @state: State to put the device into.
 */
static int pci_platform_power_transition(struct pci_dev *dev, pci_power_t state)
{
        int error;

        if (platform_pci_power_manageable(dev)) {
                error = platform_pci_set_power_state(dev, state);
                if (!error)
                        pci_update_current_state(dev, state);
        } else {
                error = -ENODEV;
                /* Fall back to PCI_D0 if native PM is not supported */
                if (!dev->pm_cap)
                        dev->current_state = PCI_D0;
        }

        return error;
}

/**
 * __pci_start_power_transition - Start power transition of a PCI device
 * @dev: PCI device to handle.
 * @state: State to put the device into.
 */
static void __pci_start_power_transition(struct pci_dev *dev, pci_power_t state)
{
        if (state == PCI_D0)
                pci_platform_power_transition(dev, PCI_D0);
}

/**
 * __pci_complete_power_transition - Complete power transition of a PCI device
 * @dev: PCI device to handle.
 * @state: State to put the device into.
 *
 * This function should not be called directly by device drivers.
 */
int __pci_complete_power_transition(struct pci_dev *dev, pci_power_t state)
{
        return state > PCI_D0 ?
                        pci_platform_power_transition(dev, state) : -EINVAL;
}
EXPORT_SYMBOL_GPL(__pci_complete_power_transition);

/**
 * pci_set_power_state - Set the power state of a PCI device
 * @dev: PCI device to handle.
 * @state: PCI power state (D0, D1, D2, D3hot) to put the device into.
 *
 * Transition a device to a new power state, using the platform firmware and/or
 * the device's PCI PM registers.
 *
 * RETURN VALUE:
 * -EINVAL if the requested state is invalid.
 * -EIO if device does not support PCI PM or its PM capabilities register has a
 * wrong version, or device doesn't support the requested state.
 * 0 if device already is in the requested state.
 * 0 if device's power state has been successfully changed.
 */
int pci_set_power_state(struct pci_dev *dev, pci_power_t state)
{
        int error;

        /* bound the state we're entering */
        if (state > PCI_D3hot)
                state = PCI_D3hot;
        else if (state < PCI_D0)
                state = PCI_D0;
        else if ((state == PCI_D1 || state == PCI_D2) && pci_no_d1d2(dev))
                /*
                 * If the device or the parent bridge do not support PCI PM,
                 * ignore the request if we're doing anything other than putting
                 * it into D0 (which would only happen on boot).
                 */
                return 0;

        /* Check if we're already there */
        if (dev->current_state == state)
                return 0;

        __pci_start_power_transition(dev, state);

        /* This device is quirked not to be put into D3, so
           don't put it in D3 */
        if (state == PCI_D3hot && (dev->dev_flags & PCI_DEV_FLAGS_NO_D3))
                return 0;

        error = pci_raw_set_power_state(dev, state);

        if (!__pci_complete_power_transition(dev, state))
                error = 0;

        return error;
}

/**
 * pci_choose_state - Choose the power state of a PCI device
 * @dev: PCI device to be suspended
 * @state: target sleep state for the whole system. This is the value
 *      that is passed to suspend() function.
 *
 * Returns PCI power state suitable for given device and given system
 * message.
 */

pci_power_t pci_choose_state(struct pci_dev *dev, pm_message_t state)
{
        pci_power_t ret;

        if (!pci_find_capability(dev, PCI_CAP_ID_PM))
                return PCI_D0;

        ret = platform_pci_choose_state(dev);
        if (ret != PCI_POWER_ERROR)
                return ret;

        switch (state.event) {
        case PM_EVENT_ON:
                return PCI_D0;
        case PM_EVENT_FREEZE:
        case PM_EVENT_PRETHAW:
                /* REVISIT both freeze and pre-thaw "should" use D0 */
        case PM_EVENT_SUSPEND:
        case PM_EVENT_HIBERNATE:
                return PCI_D3hot;
        default:
                dev_info(&dev->dev, "unrecognized suspend event %d\n",
                         state.event);
                BUG();
        }
        return PCI_D0;
}

EXPORT_SYMBOL(pci_choose_state);

#define PCI_EXP_SAVE_REGS       7

#define pcie_cap_has_devctl(type, flags)        1
#define pcie_cap_has_lnkctl(type, flags)                \
                ((flags & PCI_EXP_FLAGS_VERS) > 1 ||    \
                 (type == PCI_EXP_TYPE_ROOT_PORT ||     \
                  type == PCI_EXP_TYPE_ENDPOINT ||      \
                  type == PCI_EXP_TYPE_LEG_END))
#define pcie_cap_has_sltctl(type, flags)                \
                ((flags & PCI_EXP_FLAGS_VERS) > 1 ||    \
                 ((type == PCI_EXP_TYPE_ROOT_PORT) ||   \
                  (type == PCI_EXP_TYPE_DOWNSTREAM &&   \
                   (flags & PCI_EXP_FLAGS_SLOT))))
#define pcie_cap_has_rtctl(type, flags)                 \
                ((flags & PCI_EXP_FLAGS_VERS) > 1 ||    \
                 (type == PCI_EXP_TYPE_ROOT_PORT ||     \
                  type == PCI_EXP_TYPE_RC_EC))
#define pcie_cap_has_devctl2(type, flags)               \
                ((flags & PCI_EXP_FLAGS_VERS) > 1)
#define pcie_cap_has_lnkctl2(type, flags)               \
                ((flags & PCI_EXP_FLAGS_VERS) > 1)
#define pcie_cap_has_sltctl2(type, flags)               \
                ((flags & PCI_EXP_FLAGS_VERS) > 1)

static int pci_save_pcie_state(struct pci_dev *dev)
{
        int pos, i = 0;
        struct pci_cap_saved_state *save_state;
        u16 *cap;
        u16 flags;

        pos = pci_find_capability(dev, PCI_CAP_ID_EXP);
        if (pos <= 0)
                return 0;

        save_state = pci_find_saved_cap(dev, PCI_CAP_ID_EXP);
        if (!save_state) {
                dev_err(&dev->dev, "buffer not found in %s\n", __func__);
                return -ENOMEM;
        }
        cap = (u16 *)&save_state->data[0];

        pci_read_config_word(dev, pos + PCI_EXP_FLAGS, &flags);

        if (pcie_cap_has_devctl(dev->pcie_type, flags))
                pci_read_config_word(dev, pos + PCI_EXP_DEVCTL, &cap[i++]);
        if (pcie_cap_has_lnkctl(dev->pcie_type, flags))
                pci_read_config_word(dev, pos + PCI_EXP_LNKCTL, &cap[i++]);
        if (pcie_cap_has_sltctl(dev->pcie_type, flags))
                pci_read_config_word(dev, pos + PCI_EXP_SLTCTL, &cap[i++]);
        if (pcie_cap_has_rtctl(dev->pcie_type, flags))
                pci_read_config_word(dev, pos + PCI_EXP_RTCTL, &cap[i++]);
        if (pcie_cap_has_devctl2(dev->pcie_type, flags))
                pci_read_config_word(dev, pos + PCI_EXP_DEVCTL2, &cap[i++]);
        if (pcie_cap_has_lnkctl2(dev->pcie_type, flags))
                pci_read_config_word(dev, pos + PCI_EXP_LNKCTL2, &cap[i++]);
        if (pcie_cap_has_sltctl2(dev->pcie_type, flags))
                pci_read_config_word(dev, pos + PCI_EXP_SLTCTL2, &cap[i++]);

        return 0;
}

static void pci_restore_pcie_state(struct pci_dev *dev)
{
        int i = 0, pos;
        struct pci_cap_saved_state *save_state;
        u16 *cap;
        u16 flags;

        save_state = pci_find_saved_cap(dev, PCI_CAP_ID_EXP);
        pos = pci_find_capability(dev, PCI_CAP_ID_EXP);
        if (!save_state || pos <= 0)
                return;
        cap = (u16 *)&save_state->data[0];

        pci_read_config_word(dev, pos + PCI_EXP_FLAGS, &flags);

        if (pcie_cap_has_devctl(dev->pcie_type, flags))
                pci_write_config_word(dev, pos + PCI_EXP_DEVCTL, cap[i++]);
        if (pcie_cap_has_lnkctl(dev->pcie_type, flags))
                pci_write_config_word(dev, pos + PCI_EXP_LNKCTL, cap[i++]);
        if (pcie_cap_has_sltctl(dev->pcie_type, flags))
                pci_write_config_word(dev, pos + PCI_EXP_SLTCTL, cap[i++]);
        if (pcie_cap_has_rtctl(dev->pcie_type, flags))
                pci_write_config_word(dev, pos + PCI_EXP_RTCTL, cap[i++]);
        if (pcie_cap_has_devctl2(dev->pcie_type, flags))
                pci_write_config_word(dev, pos + PCI_EXP_DEVCTL2, cap[i++]);
        if (pcie_cap_has_lnkctl2(dev->pcie_type, flags))
                pci_write_config_word(dev, pos + PCI_EXP_LNKCTL2, cap[i++]);
        if (pcie_cap_has_sltctl2(dev->pcie_type, flags))
                pci_write_config_word(dev, pos + PCI_EXP_SLTCTL2, cap[i++]);
}


static int pci_save_pcix_state(struct pci_dev *dev)
{
        int pos;
        struct pci_cap_saved_state *save_state;

        pos = pci_find_capability(dev, PCI_CAP_ID_PCIX);
        if (pos <= 0)
                return 0;

        save_state = pci_find_saved_cap(dev, PCI_CAP_ID_PCIX);
        if (!save_state) {
                dev_err(&dev->dev, "buffer not found in %s\n", __func__);
                return -ENOMEM;
        }

        pci_read_config_word(dev, pos + PCI_X_CMD, (u16 *)save_state->data);

        return 0;
}

static void pci_restore_pcix_state(struct pci_dev *dev)
{
        int i = 0, pos;
        struct pci_cap_saved_state *save_state;
        u16 *cap;

        save_state = pci_find_saved_cap(dev, PCI_CAP_ID_PCIX);
        pos = pci_find_capability(dev, PCI_CAP_ID_PCIX);
        if (!save_state || pos <= 0)
                return;
        cap = (u16 *)&save_state->data[0];

        pci_write_config_word(dev, pos + PCI_X_CMD, cap[i++]);
}


/**
 * pci_save_state - save the PCI configuration space of a device before suspending
 * @dev: - PCI device that we're dealing with
 */
int
pci_save_state(struct pci_dev *dev)
{
        int i;
        /* XXX: 100% dword access ok here? */
        for (i = 0; i < 16; i++)
                pci_read_config_dword(dev, i * 4,&dev->saved_config_space[i]);
        dev->state_saved = true;
        if ((i = pci_save_pcie_state(dev)) != 0)
                return i;
        if ((i = pci_save_pcix_state(dev)) != 0)
                return i;
        return 0;
}

/** 
 * pci_restore_state - Restore the saved state of a PCI device
 * @dev: - PCI device that we're dealing with
 */
int 
pci_restore_state(struct pci_dev *dev)
{
        int i;
        u32 val;

        /* PCI Express register must be restored first */
        pci_restore_pcie_state(dev);

        /*
         * The Base Address register should be programmed before the command
         * register(s)
         */
        for (i = 15; i >= 0; i--) {
                pci_read_config_dword(dev, i * 4, &val);
                if (val != dev->saved_config_space[i]) {
                        dev_printk(KERN_DEBUG, &dev->dev, "restoring config "
                                "space at offset %#x (was %#x, writing %#x)\n",
                                i, val, (int)dev->saved_config_space[i]);
                        pci_write_config_dword(dev,i * 4,
                                dev->saved_config_space[i]);
                }
        }
        pci_restore_pcix_state(dev);
        pci_restore_msi_state(dev);
        pci_restore_iov_state(dev);

        return 0;
}

static int do_pci_enable_device(struct pci_dev *dev, int bars)
{
        int err;

        err = pci_set_power_state(dev, PCI_D0);
        if (err < 0 && err != -EIO)
                return err;
        err = pcibios_enable_device(dev, bars);
        if (err < 0)
                return err;
        pci_fixup_device(pci_fixup_enable, dev);

        return 0;
}

/**
 * pci_reenable_device - Resume abandoned device
 * @dev: PCI device to be resumed
 *
 *  Note this function is a backend of pci_default_resume and is not supposed
 *  to be called by normal code, write proper resume handler and use it instead.
 */
int pci_reenable_device(struct pci_dev *dev)
{
        if (pci_is_enabled(dev))
                return do_pci_enable_device(dev, (1 << PCI_NUM_RESOURCES) - 1);
        return 0;
}

static int __pci_enable_device_flags(struct pci_dev *dev,
                                     resource_size_t flags)
{
        int err;
        int i, bars = 0;

        if (atomic_add_return(1, &dev->enable_cnt) > 1)
                return 0;               /* already enabled */

        for (i = 0; i < DEVICE_COUNT_RESOURCE; i++)
                if (dev->resource[i].flags & flags)
                        bars |= (1 << i);

        err = do_pci_enable_device(dev, bars);
        if (err < 0)
                atomic_dec(&dev->enable_cnt);
        return err;
}

/**
 * pci_enable_device_io - Initialize a device for use with IO space
 * @dev: PCI device to be initialized
 *
 *  Initialize device before it's used by a driver. Ask low-level code
 *  to enable I/O resources. Wake up the device if it was suspended.
 *  Beware, this function can fail.
 */
int pci_enable_device_io(struct pci_dev *dev)
{
        return __pci_enable_device_flags(dev, IORESOURCE_IO);
}

/**
 * pci_enable_device_mem - Initialize a device for use with Memory space
 * @dev: PCI device to be initialized
 *
 *  Initialize device before it's used by a driver. Ask low-level code
 *  to enable Memory resources. Wake up the device if it was suspended.
 *  Beware, this function can fail.
 */
int pci_enable_device_mem(struct pci_dev *dev)
{
        return __pci_enable_device_flags(dev, IORESOURCE_MEM);
}

/**
 * pci_enable_device - Initialize device before it's used by a driver.
 * @dev: PCI device to be initialized
 *
 *  Initialize device before it's used by a driver. Ask low-level code
 *  to enable I/O and memory. Wake up the device if it was suspended.
 *  Beware, this function can fail.
 *
 *  Note we don't actually enable the device many times if we call
 *  this function repeatedly (we just increment the count).
 */
int pci_enable_device(struct pci_dev *dev)
{
        return __pci_enable_device_flags(dev, IORESOURCE_MEM | IORESOURCE_IO);
}

/*
 * Managed PCI resources.  This manages device on/off, intx/msi/msix
 * on/off and BAR regions.  pci_dev itself records msi/msix status, so
 * there's no need to track it separately.  pci_devres is initialized
 * when a device is enabled using managed PCI device enable interface.
 */
struct pci_devres {
        unsigned int enabled:1;
        unsigned int pinned:1;
        unsigned int orig_intx:1;
        unsigned int restore_intx:1;
        u32 region_mask;
};

static void pcim_release(struct device *gendev, void *res)
{
        struct pci_dev *dev = container_of(gendev, struct pci_dev, dev);
        struct pci_devres *this = res;
        int i;

        if (dev->msi_enabled)
                pci_disable_msi(dev);
        if (dev->msix_enabled)
                pci_disable_msix(dev);

        for (i = 0; i < DEVICE_COUNT_RESOURCE; i++)
                if (this->region_mask & (1 << i))
                        pci_release_region(dev, i);

        if (this->restore_intx)
                pci_intx(dev, this->orig_intx);

        if (this->enabled && !this->pinned)
                pci_disable_device(dev);
}

static struct pci_devres * get_pci_dr(struct pci_dev *pdev)
{
        struct pci_devres *dr, *new_dr;

        dr = devres_find(&pdev->dev, pcim_release, NULL, NULL);
        if (dr)
                return dr;

        new_dr = devres_alloc(pcim_release, sizeof(*new_dr), GFP_KERNEL);
        if (!new_dr)
                return NULL;
        return devres_get(&pdev->dev, new_dr, NULL, NULL);
}

static struct pci_devres * find_pci_dr(struct pci_dev *pdev)
{
        if (pci_is_managed(pdev))
                return devres_find(&pdev->dev, pcim_release, NULL, NULL);
        return NULL;
}

/**
 * pcim_enable_device - Managed pci_enable_device()
 * @pdev: PCI device to be initialized
 *
 * Managed pci_enable_device().
 */
int pcim_enable_device(struct pci_dev *pdev)
{
        struct pci_devres *dr;
        int rc;

        dr = get_pci_dr(pdev);
        if (unlikely(!dr))
                return -ENOMEM;
        if (dr->enabled)
                return 0;

        rc = pci_enable_device(pdev);
        if (!rc) {
                pdev->is_managed = 1;
                dr->enabled = 1;
        }
        return rc;
}

/**
 * pcim_pin_device - Pin managed PCI device
 * @pdev: PCI device to pin
 *
 * Pin managed PCI device @pdev.  Pinned device won't be disabled on
 * driver detach.  @pdev must have been enabled with
 * pcim_enable_device().
 */
void pcim_pin_device(struct pci_dev *pdev)
{
        struct pci_devres *dr;

        dr = find_pci_dr(pdev);
        WARN_ON(!dr || !dr->enabled);
        if (dr)
                dr->pinned = 1;
}

/**
 * pcibios_disable_device - disable arch specific PCI resources for device dev
 * @dev: the PCI device to disable
 *
 * Disables architecture specific PCI resources for the device. This
 * is the default implementation. Architecture implementations can
 * override this.
 */
void __attribute__ ((weak)) pcibios_disable_device (struct pci_dev *dev) {}

static void do_pci_disable_device(struct pci_dev *dev)
{
        u16 pci_command;

        pci_read_config_word(dev, PCI_COMMAND, &pci_command);
        if (pci_command & PCI_COMMAND_MASTER) {
                pci_command &= ~PCI_COMMAND_MASTER;
                pci_write_config_word(dev, PCI_COMMAND, pci_command);
        }

        pcibios_disable_device(dev);
}

/**
 * pci_disable_enabled_device - Disable device without updating enable_cnt
 * @dev: PCI device to disable
 *
 * NOTE: This function is a backend of PCI power management routines and is
 * not supposed to be called drivers.
 */
void pci_disable_enabled_device(struct pci_dev *dev)
{
        if (pci_is_enabled(dev))
                do_pci_disable_device(dev);
}

/**
 * pci_disable_device - Disable PCI device after use
 * @dev: PCI device to be disabled
 *
 * Signal to the system that the PCI device is not in use by the system
 * anymore.  This only involves disabling PCI bus-mastering, if active.
 *
 * Note we don't actually disable the device until all callers of
 * pci_device_enable() have called pci_device_disable().
 */
void
pci_disable_device(struct pci_dev *dev)
{
        struct pci_devres *dr;

        dr = find_pci_dr(dev);
        if (dr)
                dr->enabled = 0;

        if (atomic_sub_return(1, &dev->enable_cnt) != 0)
                return;

        do_pci_disable_device(dev);

        dev->is_busmaster = 0;
}

/**
 * pcibios_set_pcie_reset_state - set reset state for device dev
 * @dev: the PCI-E device reset
 * @state: Reset state to enter into
 *
 *
 * Sets the PCI-E reset state for the device. This is the default
 * implementation. Architecture implementations can override this.
 */
int __attribute__ ((weak)) pcibios_set_pcie_reset_state(struct pci_dev *dev,
                                                        enum pcie_reset_state state)
{
        return -EINVAL;
}

/**
 * pci_set_pcie_reset_state - set reset state for device dev
 * @dev: the PCI-E device reset
 * @state: Reset state to enter into
 *
 *
 * Sets the PCI reset state for the device.
 */
int pci_set_pcie_reset_state(struct pci_dev *dev, enum pcie_reset_state state)
{
        return pcibios_set_pcie_reset_state(dev, state);
}

/**
 * pci_pme_capable - check the capability of PCI device to generate PME#
 * @dev: PCI device to handle.
 * @state: PCI state from which device will issue PME#.
 */
bool pci_pme_capable(struct pci_dev *dev, pci_power_t state)
{
        if (!dev->pm_cap)
                return false;

        return !!(dev->pme_support & (1 << state));
}

/**
 * pci_pme_active - enable or disable PCI device's PME# function
 * @dev: PCI device to handle.
 * @enable: 'true' to enable PME# generation; 'false' to disable it.
 *
 * The caller must verify that the device is capable of generating PME# before
 * calling this function with @enable equal to 'true'.
 */
void pci_pme_active(struct pci_dev *dev, bool enable)
{
        u16 pmcsr;

        if (!dev->pm_cap)
                return;

        pci_read_config_word(dev, dev->pm_cap + PCI_PM_CTRL, &pmcsr);
        /* Clear PME_Status by writing 1 to it and enable PME# */
        pmcsr |= PCI_PM_CTRL_PME_STATUS | PCI_PM_CTRL_PME_ENABLE;
        if (!enable)
                pmcsr &= ~PCI_PM_CTRL_PME_ENABLE;

        pci_write_config_word(dev, dev->pm_cap + PCI_PM_CTRL, pmcsr);

        dev_printk(KERN_INFO, &dev->dev, "PME# %s\n",
                        enable ? "enabled" : "disabled");
}

/**
 * pci_enable_wake - enable PCI device as wakeup event source
 * @dev: PCI device affected
 * @state: PCI state from which device will issue wakeup events
 * @enable: True to enable event generation; false to disable
 *
 * This enables the device as a wakeup event source, or disables it.
 * When such events involves platform-specific hooks, those hooks are
 * called automatically by this routine.
 *
 * Devices with legacy power management (no standard PCI PM capabilities)
 * always require such platform hooks.
 *
 * RETURN VALUE:
 * 0 is returned on success
 * -EINVAL is returned if device is not supposed to wake up the system
 * Error code depending on the platform is returned if both the platform and
 * the native mechanism fail to enable the generation of wake-up events
 */
int pci_enable_wake(struct pci_dev *dev, pci_power_t state, int enable)
{
        int error = 0;
        bool pme_done = false;

        if (enable && !device_may_wakeup(&dev->dev))
                return -EINVAL;

        /*
         * According to "PCI System Architecture" 4th ed. by Tom Shanley & Don
         * Anderson we should be doing PME# wake enable followed by ACPI wake
         * enable.  To disable wake-up we call the platform first, for symmetry.
         */

        if (!enable && platform_pci_can_wakeup(dev))
                error = platform_pci_sleep_wake(dev, false);

        if (!enable || pci_pme_capable(dev, state)) {
                pci_pme_active(dev, enable);
                pme_done = true;
        }

        if (enable && platform_pci_can_wakeup(dev))
                error = platform_pci_sleep_wake(dev, true);

        return pme_done ? 0 : error;
}

/**
 * pci_wake_from_d3 - enable/disable device to wake up from D3_hot or D3_cold
 * @dev: PCI device to prepare
 * @enable: True to enable wake-up event generation; false to disable
 *
 * Many drivers want the device to wake up the system from D3_hot or D3_cold
 * and this function allows them to set that up cleanly - pci_enable_wake()
 * should not be called twice in a row to enable wake-up due to PCI PM vs ACPI
 * ordering constraints.
 *
 * This function only returns error code if the device is not capable of
 * generating PME# from both D3_hot and D3_cold, and the platform is unable to
 * enable wake-up power for it.
 */
int pci_wake_from_d3(struct pci_dev *dev, bool enable)
{
        return pci_pme_capable(dev, PCI_D3cold) ?
                        pci_enable_wake(dev, PCI_D3cold, enable) :
                        pci_enable_wake(dev, PCI_D3hot, enable);
}

/**
 * pci_target_state - find an appropriate low power state for a given PCI dev
 * @dev: PCI device
 *
 * Use underlying platform code to find a supported low power state for @dev.
 * If the platform can't manage @dev, return the deepest state from which it
 * can generate wake events, based on any available PME info.
 */
pci_power_t pci_target_state(struct pci_dev *dev)
{
        pci_power_t target_state = PCI_D3hot;

        if (platform_pci_power_manageable(dev)) {
                /*
                 * Call the platform to choose the target state of the device
                 * and enable wake-up from this state if supported.
                 */
                pci_power_t state = platform_pci_choose_state(dev);

                switch (state) {
                case PCI_POWER_ERROR:
                case PCI_UNKNOWN:
                        break;
                case PCI_D1:
                case PCI_D2:
                        if (pci_no_d1d2(dev))
                                break;
                default:
                        target_state = state;
                }
        } else if (!dev->pm_cap) {
                target_state = PCI_D0;
        } else if (device_may_wakeup(&dev->dev)) {
                /*
                 * Find the deepest state from which the device can generate
                 * wake-up events, make it the target state and enable device
                 * to generate PME#.
                 */
                if (dev->pme_support) {
                        while (target_state
                              && !(dev->pme_support & (1 << target_state)))
                                target_state--;
                }
        }

        return target_state;
}

/**
 * pci_prepare_to_sleep - prepare PCI device for system-wide transition into a sleep state
 * @dev: Device to handle.
 *
 * Choose the power state appropriate for the device depending on whether
 * it can wake up the system and/or is power manageable by the platform
 * (PCI_D3hot is the default) and put the device into that state.
 */
int pci_prepare_to_sleep(struct pci_dev *dev)
{
        pci_power_t target_state = pci_target_state(dev);
        int error;

        if (target_state == PCI_POWER_ERROR)
                return -EIO;

        pci_enable_wake(dev, target_state, device_may_wakeup(&dev->dev));

        error = pci_set_power_state(dev, target_state);

        if (error)
                pci_enable_wake(dev, target_state, false);

        return error;
}

/**
 * pci_back_from_sleep - turn PCI device on during system-wide transition into working state
 * @dev: Device to handle.
 *
 * Disable device's sytem wake-up capability and put it into D0.
 */
int pci_back_from_sleep(struct pci_dev *dev)
{
        pci_enable_wake(dev, PCI_D0, false);
        return pci_set_power_state(dev, PCI_D0);
}

/**
 * pci_pm_init - Initialize PM functions of given PCI device
 * @dev: PCI device to handle.
 */
void pci_pm_init(struct pci_dev *dev)
{
        int pm;
        u16 pmc;

        dev->pm_cap = 0;

        /* find PCI PM capability in list */
        pm = pci_find_capability(dev, PCI_CAP_ID_PM);
        if (!pm)
                return;
        /* Check device's ability to generate PME# */
        pci_read_config_word(dev, pm + PCI_PM_PMC, &pmc);

        if ((pmc & PCI_PM_CAP_VER_MASK) > 3) {
                dev_err(&dev->dev, "unsupported PM cap regs version (%u)\n",
                        pmc & PCI_PM_CAP_VER_MASK);
                return;
        }

        dev->pm_cap = pm;

        dev->d1_support = false;
        dev->d2_support = false;
        if (!pci_no_d1d2(dev)) {
                if (pmc & PCI_PM_CAP_D1)
                        dev->d1_support = true;
                if (pmc & PCI_PM_CAP_D2)
                        dev->d2_support = true;

                if (dev->d1_support || dev->d2_support)
                        dev_printk(KERN_DEBUG, &dev->dev, "supports%s%s\n",
                                   dev->d1_support ? " D1" : "",
                                   dev->d2_support ? " D2" : "");
        }

        pmc &= PCI_PM_CAP_PME_MASK;
        if (pmc) {
                dev_info(&dev->dev, "PME# supported from%s%s%s%s%s\n",
                         (pmc & PCI_PM_CAP_PME_D0) ? " D0" : "",
                         (pmc & PCI_PM_CAP_PME_D1) ? " D1" : "",
                         (pmc & PCI_PM_CAP_PME_D2) ? " D2" : "",
                         (pmc & PCI_PM_CAP_PME_D3) ? " D3hot" : "",
                         (pmc & PCI_PM_CAP_PME_D3cold) ? " D3cold" : "");
                dev->pme_support = pmc >> PCI_PM_CAP_PME_SHIFT;
                /*
                 * Make device's PM flags reflect the wake-up capability, but
                 * let the user space enable it to wake up the system as needed.
                 */
                device_set_wakeup_capable(&dev->dev, true);
                device_set_wakeup_enable(&dev->dev, false);
                /* Disable the PME# generation functionality */
                pci_pme_active(dev, false);
        } else {
                dev->pme_support = 0;
        }
}

/**
 * platform_pci_wakeup_init - init platform wakeup if present
 * @dev: PCI device
 *
 * Some devices don't have PCI PM caps but can still generate wakeup
 * events through platform methods (like ACPI events).  If @dev supports
 * platform wakeup events, set the device flag to indicate as much.  This
 * may be redundant if the device also supports PCI PM caps, but double
 * initialization should be safe in that case.
 */
void platform_pci_wakeup_init(struct pci_dev *dev)
{
        if (!platform_pci_can_wakeup(dev))
                return;

        device_set_wakeup_capable(&dev->dev, true);
        device_set_wakeup_enable(&dev->dev, false);
        platform_pci_sleep_wake(dev, false);
}

/**
 * pci_add_save_buffer - allocate buffer for saving given capability registers
 * @dev: the PCI device
 * @cap: the capability to allocate the buffer for
 * @size: requested size of the buffer
 */
static int pci_add_cap_save_buffer(
        struct pci_dev *dev, char cap, unsigned int size)
{
        int pos;
        struct pci_cap_saved_state *save_state;

        pos = pci_find_capability(dev, cap);
        if (pos <= 0)
                return 0;

        save_state = kzalloc(sizeof(*save_state) + size, GFP_KERNEL);
        if (!save_state)
                return -ENOMEM;

        save_state->cap_nr = cap;
        pci_add_saved_cap(dev, save_state);

        return 0;
}

/**
 * pci_allocate_cap_save_buffers - allocate buffers for saving capabilities
 * @dev: the PCI device
 */
void pci_allocate_cap_save_buffers(struct pci_dev *dev)
{
        int error;

        error = pci_add_cap_save_buffer(dev, PCI_CAP_ID_EXP,
                                        PCI_EXP_SAVE_REGS * sizeof(u16));
        if (error)
                dev_err(&dev->dev,
                        "unable to preallocate PCI Express save buffer\n");

        error = pci_add_cap_save_buffer(dev, PCI_CAP_ID_PCIX, sizeof(u16));
        if (error)
                dev_err(&dev->dev,
                        "unable to preallocate PCI-X save buffer\n");
}

/**
 * pci_enable_ari - enable ARI forwarding if hardware support it
 * @dev: the PCI device
 */
void pci_enable_ari(struct pci_dev *dev)
{
        int pos;
        u32 cap;
        u16 ctrl;
        struct pci_dev *bridge;

        if (!dev->is_pcie || dev->devfn)
                return;

        pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ARI);
        if (!pos)
                return;

        bridge = dev->bus->self;
        if (!bridge || !bridge->is_pcie)
                return;

        pos = pci_find_capability(bridge, PCI_CAP_ID_EXP);
        if (!pos)
                return;

        pci_read_config_dword(bridge, pos + PCI_EXP_DEVCAP2, &cap);
        if (!(cap & PCI_EXP_DEVCAP2_ARI))
                return;

        pci_read_config_word(bridge, pos + PCI_EXP_DEVCTL2, &ctrl);
        ctrl |= PCI_EXP_DEVCTL2_ARI;
        pci_write_config_word(bridge, pos + PCI_EXP_DEVCTL2, ctrl);

        bridge->ari_enabled = 1;
}

/**
 * pci_swizzle_interrupt_pin - swizzle INTx for device behind bridge
 * @dev: the PCI device
 * @pin: the INTx pin (1=INTA, 2=INTB, 3=INTD, 4=INTD)
 *
 * Perform INTx swizzling for a device behind one level of bridge.  This is
 * required by section 9.1 of the PCI-to-PCI bridge specification for devices
 * behind bridges on add-in cards.
 */
u8 pci_swizzle_interrupt_pin(struct pci_dev *dev, u8 pin)
{
        return (((pin - 1) + PCI_SLOT(dev->devfn)) % 4) + 1;
}

int
pci_get_interrupt_pin(struct pci_dev *dev, struct pci_dev **bridge)
{
        u8 pin;

        pin = dev->pin;
        if (!pin)
                return -1;

        while (dev->bus->parent) {
                pin = pci_swizzle_interrupt_pin(dev, pin);
                dev = dev->bus->self;
        }
        *bridge = dev;
        return pin;
}

/**
 * pci_common_swizzle - swizzle INTx all the way to root bridge
 * @dev: the PCI device
 * @pinp: pointer to the INTx pin value (1=INTA, 2=INTB, 3=INTD, 4=INTD)
 *
 * Perform INTx swizzling for a device.  This traverses through all PCI-to-PCI
 * bridges all the way up to a PCI root bus.
 */
u8 pci_common_swizzle(struct pci_dev *dev, u8 *pinp)
{
        u8 pin = *pinp;

        while (dev->bus->parent) {
                pin = pci_swizzle_interrupt_pin(dev, pin);
                dev = dev->bus->self;
        }
        *pinp = pin;
        return PCI_SLOT(dev->devfn);
}

/**
 *      pci_release_region - Release a PCI bar
 *      @pdev: PCI device whose resources were previously reserved by pci_request_region
 *      @bar: BAR to release
 *
 *      Releases the PCI I/O and memory resources previously reserved by a
 *      successful call to pci_request_region.  Call this function only
 *      after all use of the PCI regions has ceased.
 */
void pci_release_region(struct pci_dev *pdev, int bar)
{
        struct pci_devres *dr;

        if (pci_resource_len(pdev, bar) == 0)
                return;
        if (pci_resource_flags(pdev, bar) & IORESOURCE_IO)
                release_region(pci_resource_start(pdev, bar),
                                pci_resource_len(pdev, bar));
        else if (pci_resource_flags(pdev, bar) & IORESOURCE_MEM)
                release_mem_region(pci_resource_start(pdev, bar),
                                pci_resource_len(pdev, bar));

        dr = find_pci_dr(pdev);
        if (dr)
                dr->region_mask &= ~(1 << bar);
}

/**
 *      __pci_request_region - Reserved PCI I/O and memory resource
 *      @pdev: PCI device whose resources are to be reserved
 *      @bar: BAR to be reserved
 *      @res_name: Name to be associated with resource.
 *      @exclusive: whether the region access is exclusive or not
 *
 *      Mark the PCI region associated with PCI device @pdev BR @bar as
 *      being reserved by owner @res_name.  Do not access any
 *      address inside the PCI regions unless this call returns
 *      successfully.
 *
 *      If @exclusive is set, then the region is marked so that userspace
 *      is explicitly not allowed to map the resource via /dev/mem or
 *      sysfs MMIO access.
 *
 *      Returns 0 on success, or %EBUSY on error.  A warning
 *      message is also printed on failure.
 */
static int __pci_request_region(struct pci_dev *pdev, int bar, const char *res_name,
                                                                        int exclusive)
{
        struct pci_devres *dr;

        if (pci_resource_len(pdev, bar) == 0)
                return 0;
                
        if (pci_resource_flags(pdev, bar) & IORESOURCE_IO) {
                if (!request_region(pci_resource_start(pdev, bar),
                            pci_resource_len(pdev, bar), res_name))
                        goto err_out;
        }
        else if (pci_resource_flags(pdev, bar) & IORESOURCE_MEM) {
                if (!__request_mem_region(pci_resource_start(pdev, bar),
                                        pci_resource_len(pdev, bar), res_name,
                                        exclusive))
                        goto err_out;
        }

        dr = find_pci_dr(pdev);
        if (dr)
                dr->region_mask |= 1 << bar;

        return 0;

err_out:
        dev_warn(&pdev->dev, "BAR %d: can't reserve %s region %pR\n",
                 bar,
                 pci_resource_flags(pdev, bar) & IORESOURCE_IO ? "I/O" : "mem",
                 &pdev->resource[bar]);
        return -EBUSY;
}

/**
 *      pci_request_region - Reserve PCI I/O and memory resource
 *      @pdev: PCI device whose resources are to be reserved
 *      @bar: BAR to be reserved
 *      @res_name: Name to be associated with resource
 *
 *      Mark the PCI region associated with PCI device @pdev BAR @bar as
 *      being reserved by owner @res_name.  Do not access any
 *      address inside the PCI regions unless this call returns
 *      successfully.
 *
 *      Returns 0 on success, or %EBUSY on error.  A warning
 *      message is also printed on failure.
 */
int pci_request_region(struct pci_dev *pdev, int bar, const char *res_name)
{
        return __pci_request_region(pdev, bar, res_name, 0);
}

/**
 *      pci_request_region_exclusive - Reserved PCI I/O and memory resource
 *      @pdev: PCI device whose resources are to be reserved
 *      @bar: BAR to be reserved
 *      @res_name: Name to be associated with resource.
 *
 *      Mark the PCI region associated with PCI device @pdev BR @bar as
 *      being reserved by owner @res_name.  Do not access any
 *      address inside the PCI regions unless this call returns
 *      successfully.
 *
 *      Returns 0 on success, or %EBUSY on error.  A warning
 *      message is also printed on failure.
 *
 *      The key difference that _exclusive makes it that userspace is
 *      explicitly not allowed to map the resource via /dev/mem or
 *      sysfs.
 */
int pci_request_region_exclusive(struct pci_dev *pdev, int bar, const char *res_name)
{
        return __pci_request_region(pdev, bar, res_name, IORESOURCE_EXCLUSIVE);
}
/**
 * pci_release_selected_regions - Release selected PCI I/O and memory resources
 * @pdev: PCI device whose resources were previously reserved
 * @bars: Bitmask of BARs to be released
 *
 * Release selected PCI I/O and memory resources previously reserved.
 * Call this function only after all use of the PCI regions has ceased.
 */
void pci_release_selected_regions(struct pci_dev *pdev, int bars)
{
        int i;

        for (i = 0; i < 6; i++)
                if (bars & (1 << i))
                        pci_release_region(pdev, i);
}

int __pci_request_selected_regions(struct pci_dev *pdev, int bars,
                                 const char *res_name, int excl)
{
        int i;

        for (i = 0; i < 6; i++)
                if (bars & (1 << i))
                        if (__pci_request_region(pdev, i, res_name, excl))
                                goto err_out;
        return 0;

err_out:
        while(--i >= 0)
                if (bars & (1 << i))
                        pci_release_region(pdev, i);

        return -EBUSY;
}


/**
 * pci_request_selected_regions - Reserve selected PCI I/O and memory resources
 * @pdev: PCI device whose resources are to be reserved
 * @bars: Bitmask of BARs to be requested
 * @res_name: Name to be associated with resource
 */
int pci_request_selected_regions(struct pci_dev *pdev, int bars,
                                 const char *res_name)
{
        return __pci_request_selected_regions(pdev, bars, res_name, 0);
}

int pci_request_selected_regions_exclusive(struct pci_dev *pdev,
                                 int bars, const char *res_name)
{
        return __pci_request_selected_regions(pdev, bars, res_name,
                        IORESOURCE_EXCLUSIVE);
}

/**
 *      pci_release_regions - Release reserved PCI I/O and memory resources
 *      @pdev: PCI device whose resources were previously reserved by pci_request_regions
 *
 *      Releases all PCI I/O and memory resources previously reserved by a
 *      successful call to pci_request_regions.  Call this function only
 *      after all use of the PCI regions has ceased.
 */

void pci_release_regions(struct pci_dev *pdev)
{
        pci_release_selected_regions(pdev, (1 << 6) - 1);
}

/**
 *      pci_request_regions - Reserved PCI I/O and memory resources
 *      @pdev: PCI device whose resources are to be reserved
 *      @res_name: Name to be associated with resource.
 *
 *      Mark all PCI regions associated with PCI device @pdev as
 *      being reserved by owner @res_name.  Do not access any
 *      address inside the PCI regions unless this call returns
 *      successfully.
 *
 *      Returns 0 on success, or %EBUSY on error.  A warning
 *      message is also printed on failure.
 */
int pci_request_regions(struct pci_dev *pdev, const char *res_name)
{
        return pci_request_selected_regions(pdev, ((1 << 6) - 1), res_name);
}

/**
 *      pci_request_regions_exclusive - Reserved PCI I/O and memory resources
 *      @pdev: PCI device whose resources are to be reserved
 *      @res_name: Name to be associated with resource.
 *
 *      Mark all PCI regions associated with PCI device @pdev as
 *      being reserved by owner @res_name.  Do not access any
 *      address inside the PCI regions unless this call returns
 *      successfully.
 *
 *      pci_request_regions_exclusive() will mark the region so that
 *      /dev/mem and the sysfs MMIO access will not be allowed.
 *
 *      Returns 0 on success, or %EBUSY on error.  A warning
 *      message is also printed on failure.
 */
int pci_request_regions_exclusive(struct pci_dev *pdev, const char *res_name)
{
        return pci_request_selected_regions_exclusive(pdev,
                                        ((1 << 6) - 1), res_name);
}

static void __pci_set_master(struct pci_dev *dev, bool enable)
{
        u16 old_cmd, cmd;

        pci_read_config_word(dev, PCI_COMMAND, &old_cmd);
        if (enable)
                cmd = old_cmd | PCI_COMMAND_MASTER;
        else
                cmd = old_cmd & ~PCI_COMMAND_MASTER;
        if (cmd != old_cmd) {
                dev_dbg(&dev->dev, "%s bus mastering\n",
                        enable ? "enabling" : "disabling");
                pci_write_config_word(dev, PCI_COMMAND, cmd);
        }
        dev->is_busmaster = enable;
}

/**
 * pci_set_master - enables bus-mastering for device dev
 * @dev: the PCI device to enable
 *
 * Enables bus-mastering on the device and calls pcibios_set_master()
 * to do the needed arch specific settings.
 */
void pci_set_master(struct pci_dev *dev)
{
        __pci_set_master(dev, true);
        pcibios_set_master(dev);
}

/**
 * pci_clear_master - disables bus-mastering for device dev
 * @dev: the PCI device to disable
 */
void pci_clear_master(struct pci_dev *dev)
{
        __pci_set_master(dev, false);
}

#ifdef PCI_DISABLE_MWI
int pci_set_mwi(struct pci_dev *dev)
{
        return 0;
}

int pci_try_set_mwi(struct pci_dev *dev)
{
        return 0;
}

void pci_clear_mwi(struct pci_dev *dev)
{
}

#else

#ifndef PCI_CACHE_LINE_BYTES
#define PCI_CACHE_LINE_BYTES L1_CACHE_BYTES
#endif

/* This can be overridden by arch code. */
/* Don't forget this is measured in 32-bit words, not bytes */
u8 pci_cache_line_size = PCI_CACHE_LINE_BYTES / 4;

/**
 * pci_set_cacheline_size - ensure the CACHE_LINE_SIZE register is programmed
 * @dev: the PCI device for which MWI is to be enabled
 *
 * Helper function for pci_set_mwi.
 * Originally copied from drivers/net/acenic.c.
 * Copyright 1998-2001 by Jes Sorensen, <jes@trained-monkey.org>.
 *
 * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
 */
static int
pci_set_cacheline_size(struct pci_dev *dev)
{
        u8 cacheline_size;

        if (!pci_cache_line_size)
                return -EINVAL;         /* The system doesn't support MWI. */

        /* Validate current setting: the PCI_CACHE_LINE_SIZE must be
           equal to or multiple of the right value. */
        pci_read_config_byte(dev, PCI_CACHE_LINE_SIZE, &cacheline_size);
        if (cacheline_size >= pci_cache_line_size &&
            (cacheline_size % pci_cache_line_size) == 0)
                return 0;

        /* Write the correct value. */
        pci_write_config_byte(dev, PCI_CACHE_LINE_SIZE, pci_cache_line_size);
        /* Read it back. */
        pci_read_config_byte(dev, PCI_CACHE_LINE_SIZE, &cacheline_size);
        if (cacheline_size == pci_cache_line_size)
                return 0;

        dev_printk(KERN_DEBUG, &dev->dev, "cache line size of %d is not "
                   "supported\n", pci_cache_line_size << 2);

        return -EINVAL;
}

/**
 * pci_set_mwi - enables memory-write-invalidate PCI transaction
 * @dev: the PCI device for which MWI is enabled
 *
 * Enables the Memory-Write-Invalidate transaction in %PCI_COMMAND.
 *
 * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
 */
int
pci_set_mwi(struct pci_dev *dev)
{
        int rc;
        u16 cmd;

        rc = pci_set_cacheline_size(dev);
        if (rc)
                return rc;

        pci_read_config_word(dev, PCI_COMMAND, &cmd);
        if (! (cmd & PCI_COMMAND_INVALIDATE)) {
                dev_dbg(&dev->dev, "enabling Mem-Wr-Inval\n");
                cmd |= PCI_COMMAND_INVALIDATE;
                pci_write_config_word(dev, PCI_COMMAND, cmd);
        }
        
        return 0;
}

/**
 * pci_try_set_mwi - enables memory-write-invalidate PCI transaction
 * @dev: the PCI device for which MWI is enabled
 *
 * Enables the Memory-Write-Invalidate transaction in %PCI_COMMAND.
 * Callers are not required to check the return value.
 *
 * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
 */
int pci_try_set_mwi(struct pci_dev *dev)
{
        int rc = pci_set_mwi(dev);
        return rc;
}

/**
 * pci_clear_mwi - disables Memory-Write-Invalidate for device dev
 * @dev: the PCI device to disable
 *
 * Disables PCI Memory-Write-Invalidate transaction on the device
 */
void
pci_clear_mwi(struct pci_dev *dev)
{
        u16 cmd;

        pci_read_config_word(dev, PCI_COMMAND, &cmd);
        if (cmd & PCI_COMMAND_INVALIDATE) {
                cmd &= ~PCI_COMMAND_INVALIDATE;
                pci_write_config_word(dev, PCI_COMMAND, cmd);
        }
}
#endif /* ! PCI_DISABLE_MWI */

/**
 * pci_intx - enables/disables PCI INTx for device dev
 * @pdev: the PCI device to operate on
 * @enable: boolean: whether to enable or disable PCI INTx
 *
 * Enables/disables PCI INTx for device dev
 */
void
pci_intx(struct pci_dev *pdev, int enable)
{
        u16 pci_command, new;

        pci_read_config_word(pdev, PCI_COMMAND, &pci_command);

        if (enable) {
                new = pci_command & ~PCI_COMMAND_INTX_DISABLE;
        } else {
                new = pci_command | PCI_COMMAND_INTX_DISABLE;
        }

        if (new != pci_command) {
                struct pci_devres *dr;

                pci_write_config_word(pdev, PCI_COMMAND, new);

                dr = find_pci_dr(pdev);
                if (dr && !dr->restore_intx) {
                        dr->restore_intx = 1;
                        dr->orig_intx = !enable;
                }
        }
}

/**
 * pci_msi_off - disables any msi or msix capabilities
 * @dev: the PCI device to operate on
 *
 * If you want to use msi see pci_enable_msi and friends.
 * This is a lower level primitive that allows us to disable
 * msi operation at the device level.
 */
void pci_msi_off(struct pci_dev *dev)
{
        int pos;
        u16 control;

        pos = pci_find_capability(dev, PCI_CAP_ID_MSI);