spelling fixes

[mirror_ubuntu-artful-kernel.git] / drivers / pci / pci.c

/*
 *      $Id: pci.c,v 1.91 1999/01/21 13:34:01 davem Exp $
 *
 *      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/module.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <asm/dma.h>    /* isa_dma_bridge_buggy */
#include "pci.h"


/**
 * 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 __devinit
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);

#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  */

static int __pci_find_next_cap(struct pci_bus *bus, unsigned int devfn, u8 pos, int cap)
{
        u8 id;
        int ttl = 48;

        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;
}

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

        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:
                pos = PCI_CAPABILITY_LIST;
                break;
        case PCI_HEADER_TYPE_CARDBUS:
                pos = PCI_CB_CAPABILITY_LIST;
                break;
        default:
                return 0;
        }
        return __pci_find_next_cap(bus, devfn, pos, cap);
}

/**
 * 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)
{
        return __pci_bus_find_cap(dev->bus, dev->devfn, dev->hdr_type, cap);
}

/**
 * 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)
{
        u8 hdr_type;

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

        return __pci_bus_find_cap(bus, devfn, hdr_type & 0x7f, cap);
}

/**
 * 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 = 480; /* 3840 bytes, minimum 8 bytes per capability */
        int pos = 0x100;

        if (dev->cfg_size <= 256)
                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 < 0x100)
                        break;

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

        return 0;
}
EXPORT_SYMBOL_GPL(pci_find_ext_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.
 */
void
pci_restore_bars(struct pci_dev *dev)
{
        int i, numres;

        switch (dev->hdr_type) {
        case PCI_HEADER_TYPE_NORMAL:
                numres = 6;
                break;
        case PCI_HEADER_TYPE_BRIDGE:
                numres = 2;
                break;
        case PCI_HEADER_TYPE_CARDBUS:
                numres = 1;
                break;
        default:
                /* Should never get here, but just in case... */
                return;
        }

        for (i = 0; i < numres; i ++)
                pci_update_resource(dev, &dev->resource[i], i);
}

int (*platform_pci_set_power_state)(struct pci_dev *dev, pci_power_t t);

/**
 * pci_set_power_state - Set the power state of a PCI device
 * @dev: PCI device to be suspended
 * @state: PCI power state (D0, D1, D2, D3hot, D3cold) we're entering
 *
 * Transition a device to a new power state, using the Power Management 
 * Capabilities in the device's config space.
 *
 * RETURN VALUE: 
 * -EINVAL if trying to enter a lower state than we're already in.
 * 0 if we're already in the requested state.
 * -EIO if device does not support PCI PM.
 * 0 if we can successfully change the power state.
 */
int
pci_set_power_state(struct pci_dev *dev, pci_power_t state)
{
        int pm, need_restore = 0;
        u16 pmcsr, pmc;

        /* bound the state we're entering */
        if (state > PCI_D3hot)
                state = PCI_D3hot;

        /* 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 > state) {
                printk(KERN_ERR "%s(): %s: state=%d, current state=%d\n",
                        __FUNCTION__, pci_name(dev), state, dev->current_state);
                return -EINVAL;
        } else if (dev->current_state == state)
                return 0;        /* we're already there */

        /* find PCI PM capability in list */
        pm = pci_find_capability(dev, PCI_CAP_ID_PM);
        
        /* abort if the device doesn't support PM capabilities */
        if (!pm)
                return -EIO; 

        pci_read_config_word(dev,pm + PCI_PM_PMC,&pmc);
        if ((pmc & PCI_PM_CAP_VER_MASK) > 3) {
                printk(KERN_DEBUG
                       "PCI: %s has unsupported PM cap regs version (%u)\n",
                       pci_name(dev), pmc & PCI_PM_CAP_VER_MASK);
                return -EIO;
        }

        /* check if this device supports the desired state */
        if (state == PCI_D1 && !(pmc & PCI_PM_CAP_D1))
                return -EIO;
        else if (state == PCI_D2 && !(pmc & PCI_PM_CAP_D2))
                return -EIO;

        pci_read_config_word(dev, pm + 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_UNKNOWN: /* Boot-up */
                if ((pmcsr & PCI_PM_CTRL_STATE_MASK) == PCI_D3hot
                 && !(pmcsr & PCI_PM_CTRL_NO_SOFT_RESET))
                        need_restore = 1;
                /* Fall-through: force to D0 */
        default:
                pmcsr = 0;
                break;
        }

        /* enter specified state */
        pci_write_config_word(dev, pm + 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(10);
        else if (state == PCI_D2 || dev->current_state == PCI_D2)
                udelay(200);

        /*
         * Give firmware a chance to be called, such as ACPI _PRx, _PSx
         * Firmware method after native method ?
         */
        if (platform_pci_set_power_state)
                platform_pci_set_power_state(dev, state);

        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);

        return 0;
}

int (*platform_pci_choose_state)(struct pci_dev *dev, pm_message_t state);
 
/**
 * 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)
{
        int ret;

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

        if (platform_pci_choose_state) {
                ret = platform_pci_choose_state(dev, state);
                if (ret >= 0)
                        state.event = ret;
        }

        switch (state.event) {
        case PM_EVENT_ON:
                return PCI_D0;
        case PM_EVENT_FREEZE:
        case PM_EVENT_SUSPEND:
                return PCI_D3hot;
        default:
                printk("They asked me for state %d\n", state.event);
                BUG();
        }
        return PCI_D0;
}

EXPORT_SYMBOL(pci_choose_state);

/**
 * 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]);
        if ((i = pci_save_msi_state(dev)) != 0)
                return i;
        if ((i = pci_save_msix_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;
        int val;

        /*
         * 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]) {
                        printk(KERN_DEBUG "PM: Writing back config space on "
                                "device %s at offset %x (was %x, writing %x)\n",
                                pci_name(dev), i,
                                val, (int)dev->saved_config_space[i]);
                        pci_write_config_dword(dev,i * 4,
                                dev->saved_config_space[i]);
                }
        }
        pci_restore_msi_state(dev);
        pci_restore_msix_state(dev);
        return 0;
}

/**
 * pci_enable_device_bars - Initialize some of a device for use
 * @dev: PCI device to be initialized
 * @bars: bitmask of BAR's that must be configured
 *
 *  Initialize device before it's used by a driver. Ask low-level code
 *  to enable selected I/O and memory resources. Wake up the device if it 
 *  was suspended. Beware, this function can fail.
 */
 
int
pci_enable_device_bars(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;
        return 0;
}

/**
 * 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.
 */
int
pci_enable_device(struct pci_dev *dev)
{
        int err;

        if (dev->is_enabled)
                return 0;

        err = pci_enable_device_bars(dev, (1 << PCI_NUM_RESOURCES) - 1);
        if (err)
                return err;
        pci_fixup_device(pci_fixup_enable, dev);
        dev->is_enabled = 1;
        return 0;
}

/**
 * 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) {}

/**
 * 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.
 */
void
pci_disable_device(struct pci_dev *dev)
{
        u16 pci_command;

        if (dev->msi_enabled)
                disable_msi_mode(dev, pci_find_capability(dev, PCI_CAP_ID_MSI),
                        PCI_CAP_ID_MSI);
        if (dev->msix_enabled)
                disable_msi_mode(dev, pci_find_capability(dev, PCI_CAP_ID_MSI),
                        PCI_CAP_ID_MSIX);

        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);
        }
        dev->is_busmaster = 0;

        pcibios_disable_device(dev);
        dev->is_enabled = 0;
}

/**
 * pci_enable_wake - enable device to generate PME# when suspended
 * @dev: - PCI device to operate on
 * @state: - Current state of device.
 * @enable: - Flag to enable or disable generation
 * 
 * Set the bits in the device's PM Capabilities to generate PME# when
 * the system is suspended. 
 *
 * -EIO is returned if device doesn't have PM Capabilities. 
 * -EINVAL is returned if device supports it, but can't generate wake events.
 * 0 if operation is successful.
 * 
 */
int pci_enable_wake(struct pci_dev *dev, pci_power_t state, int enable)
{
        int pm;
        u16 value;

        /* find PCI PM capability in list */
        pm = pci_find_capability(dev, PCI_CAP_ID_PM);

        /* If device doesn't support PM Capabilities, but request is to disable
         * wake events, it's a nop; otherwise fail */
        if (!pm) 
                return enable ? -EIO : 0; 

        /* Check device's ability to generate PME# */
        pci_read_config_word(dev,pm+PCI_PM_PMC,&value);

        value &= PCI_PM_CAP_PME_MASK;
        value >>= ffs(PCI_PM_CAP_PME_MASK) - 1;   /* First bit of mask */

        /* Check if it can generate PME# from requested state. */
        if (!value || !(value & (1 << state))) 
                return enable ? -EINVAL : 0;

        pci_read_config_word(dev, pm + PCI_PM_CTRL, &value);

        /* Clear PME_Status by writing 1 to it and enable PME# */
        value |= PCI_PM_CTRL_PME_STATUS | PCI_PM_CTRL_PME_ENABLE;

        if (!enable)
                value &= ~PCI_PM_CTRL_PME_ENABLE;

        pci_write_config_word(dev, pm + PCI_PM_CTRL, value);
        
        return 0;
}

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

        pin = dev->pin;
        if (!pin)
                return -1;
        pin--;
        while (dev->bus->self) {
                pin = (pin + PCI_SLOT(dev->devfn)) % 4;
                dev = dev->bus->self;
        }
        *bridge = dev;
        return pin;
}

/**
 *      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)
{
        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));
}

/**
 *      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.
 *
 *      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.
 */
int pci_request_region(struct pci_dev *pdev, int bar, const char *res_name)
{
        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))
                        goto err_out;
        }
        
        return 0;

err_out:
        printk (KERN_WARNING "PCI: Unable to reserve %s region #%d:%lx@%lx for device %s\n",
                pci_resource_flags(pdev, bar) & IORESOURCE_IO ? "I/O" : "mem",
                bar + 1, /* PCI BAR # */
                pci_resource_len(pdev, bar), pci_resource_start(pdev, bar),
                pci_name(pdev));
        return -EBUSY;
}


/**
 *      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)
{
        int i;
        
        for (i = 0; i < 6; i++)
                pci_release_region(pdev, i);
}

/**
 *      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)
{
        int i;
        
        for (i = 0; i < 6; i++)
                if(pci_request_region(pdev, i, res_name))
                        goto err_out;
        return 0;

err_out:
        while(--i >= 0)
                pci_release_region(pdev, i);
                
        return -EBUSY;
}

/**
 * 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)
{
        u16 cmd;

        pci_read_config_word(dev, PCI_COMMAND, &cmd);
        if (! (cmd & PCI_COMMAND_MASTER)) {
                pr_debug("PCI: Enabling bus mastering for device %s\n", pci_name(dev));
                cmd |= PCI_COMMAND_MASTER;
                pci_write_config_word(dev, PCI_COMMAND, cmd);
        }
        dev->is_busmaster = 1;
        pcibios_set_master(dev);
}

#ifndef HAVE_ARCH_PCI_MWI
/* This can be overridden by arch code. */
u8 pci_cache_line_size = L1_CACHE_BYTES >> 2;

/**
 * pci_generic_prep_mwi - helper function for pci_set_mwi
 * @dev: the PCI device for which MWI is enabled
 *
 * Helper function for generic implementation of pcibios_prep_mwi
 * function.  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_generic_prep_mwi(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;

        printk(KERN_DEBUG "PCI: cache line size of %d is not supported "
               "by device %s\n", pci_cache_line_size << 2, pci_name(dev));

        return -EINVAL;
}
#endif /* !HAVE_ARCH_PCI_MWI */

/**
 * 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,
 * and then calls @pcibios_set_mwi to do the needed arch specific
 * operations or a generic mwi-prep function.
 *
 * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
 */
int
pci_set_mwi(struct pci_dev *dev)
{
        int rc;
        u16 cmd;

#ifdef HAVE_ARCH_PCI_MWI
        rc = pcibios_prep_mwi(dev);
#else
        rc = pci_generic_prep_mwi(dev);
#endif

        if (rc)
                return rc;

        pci_read_config_word(dev, PCI_COMMAND, &cmd);
        if (! (cmd & PCI_COMMAND_INVALIDATE)) {
                pr_debug("PCI: Enabling Mem-Wr-Inval for device %s\n", pci_name(dev));
                cmd |= PCI_COMMAND_INVALIDATE;
                pci_write_config_word(dev, PCI_COMMAND, cmd);
        }
        
        return 0;
}

/**
 * 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);
        }
}

/**
 * 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) {
                pci_write_config_word(pdev, PCI_COMMAND, new);
        }
}

#ifndef HAVE_ARCH_PCI_SET_DMA_MASK
/*
 * These can be overridden by arch-specific implementations
 */
int
pci_set_dma_mask(struct pci_dev *dev, u64 mask)
{
        if (!pci_dma_supported(dev, mask))
                return -EIO;

        dev->dma_mask = mask;

        return 0;
}
    
int
pci_set_consistent_dma_mask(struct pci_dev *dev, u64 mask)
{
        if (!pci_dma_supported(dev, mask))
                return -EIO;

        dev->dev.coherent_dma_mask = mask;

        return 0;
}
#endif
     
static int __devinit pci_init(void)
{
        struct pci_dev *dev = NULL;

        while ((dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev)) != NULL) {
                pci_fixup_device(pci_fixup_final, dev);
        }
        return 0;
}

static int __devinit pci_setup(char *str)
{
        while (str) {
                char *k = strchr(str, ',');
                if (k)
                        *k++ = 0;
                if (*str && (str = pcibios_setup(str)) && *str) {
                        if (!strcmp(str, "nomsi")) {
                                pci_no_msi();
                        } else {
                                printk(KERN_ERR "PCI: Unknown option `%s'\n",
                                                str);
                        }
                }
                str = k;
        }
        return 1;
}

device_initcall(pci_init);

__setup("pci=", pci_setup);

#if defined(CONFIG_ISA) || defined(CONFIG_EISA)
/* FIXME: Some boxes have multiple ISA bridges! */
struct pci_dev *isa_bridge;
EXPORT_SYMBOL(isa_bridge);
#endif

EXPORT_SYMBOL_GPL(pci_restore_bars);
EXPORT_SYMBOL(pci_enable_device_bars);
EXPORT_SYMBOL(pci_enable_device);
EXPORT_SYMBOL(pci_disable_device);
EXPORT_SYMBOL(pci_find_capability);
EXPORT_SYMBOL(pci_bus_find_capability);
EXPORT_SYMBOL(pci_release_regions);
EXPORT_SYMBOL(pci_request_regions);
EXPORT_SYMBOL(pci_release_region);
EXPORT_SYMBOL(pci_request_region);
EXPORT_SYMBOL(pci_set_master);
EXPORT_SYMBOL(pci_set_mwi);
EXPORT_SYMBOL(pci_clear_mwi);
EXPORT_SYMBOL_GPL(pci_intx);
EXPORT_SYMBOL(pci_set_dma_mask);
EXPORT_SYMBOL(pci_set_consistent_dma_mask);
EXPORT_SYMBOL(pci_assign_resource);
EXPORT_SYMBOL(pci_find_parent_resource);

EXPORT_SYMBOL(pci_set_power_state);
EXPORT_SYMBOL(pci_save_state);
EXPORT_SYMBOL(pci_restore_state);
EXPORT_SYMBOL(pci_enable_wake);

/* Quirk info */

EXPORT_SYMBOL(isa_dma_bridge_buggy);
EXPORT_SYMBOL(pci_pci_problems);