pci.c

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	struct pci_cap_saved_state *save_state;
	u16 *cap;

	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)
		save_state = kzalloc(sizeof(*save_state) + sizeof(u16) * 4, GFP_KERNEL);
	if (!save_state) {
		dev_err(&dev->dev, "Out of memory in pci_save_pcie_state\n");
		return -ENOMEM;
	}
	cap = (u16 *)&save_state->data[0];

	pci_read_config_word(dev, pos + PCI_EXP_DEVCTL, &cap[i++]);
	pci_read_config_word(dev, pos + PCI_EXP_LNKCTL, &cap[i++]);
	pci_read_config_word(dev, pos + PCI_EXP_SLTCTL, &cap[i++]);
	pci_read_config_word(dev, pos + PCI_EXP_RTCTL, &cap[i++]);
	pci_add_saved_cap(dev, save_state);
	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;

	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_write_config_word(dev, pos + PCI_EXP_DEVCTL, cap[i++]);
	pci_write_config_word(dev, pos + PCI_EXP_LNKCTL, cap[i++]);
	pci_write_config_word(dev, pos + PCI_EXP_SLTCTL, cap[i++]);
	pci_write_config_word(dev, pos + PCI_EXP_RTCTL, cap[i++]);
}


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

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

	save_state = pci_find_saved_cap(dev, PCI_CAP_ID_EXP);
	if (!save_state)
		save_state = kzalloc(sizeof(*save_state) + sizeof(u16), GFP_KERNEL);
	if (!save_state) {
		dev_err(&dev->dev, "Out of memory in pci_save_pcie_state\n");
		return -ENOMEM;
	}
	cap = (u16 *)&save_state->data[0];

	pci_read_config_word(dev, pos + PCI_X_CMD, &cap[i++]);
	pci_add_saved_cap(dev, save_state);
	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]);
	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]) {
			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_pcix_state(dev);
	pci_restore_msi_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 (atomic_read(&dev->enable_cnt))
		return do_pci_enable_device(dev, (1 << PCI_NUM_RESOURCES) - 1);
	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;

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

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

/**
 * 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_bars(dev, (1 << PCI_NUM_RESOURCES) - 1);
}

/*
 * 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;
	WARN_ON(!!dr->enabled);

	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) {}

/**
 * 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;
	u16 pci_command;

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

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

	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);
}

/**
 * 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_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.  Depending on the platform, devices
 * supporting the standard PCI PME# signal may require such platform hooks;
 * they always update bits in config space to allow PME# generation.
 *
 * -EIO is returned if the device can't ever be a wakeup event source.
 * -EINVAL is returned if the device can't generate wakeup events from
 * the specified PCI state.  Returns zero if the operation is successful.
 */
int pci_enable_wake(struct pci_dev *dev, pci_power_t state, int enable)
{
	int pm;
	int status;
	u16 value;

	/* Note that drivers should verify device_may_wakeup(&dev->dev)
	 * before calling this function.  Platform code should report
	 * errors when drivers try to enable wakeup on devices that
	 * can't issue wakeups, or on which wakeups were disabled by
	 * userspace updating the /sys/devices.../power/wakeup file.
	 */

	status = call_platform_enable_wakeup(&dev->dev, enable);

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

	/* If device doesn't support PM Capabilities, but caller wants to
	 * disable wake events, it's a NOP.  Otherwise fail unless the
	 * platform hooks handled this legacy device already.
	 */
	if (!pm)
		return enable ? status : 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))) {
		/* if it can't, revert what the platform hook changed,
		 * always reporting the base "EINVAL, can't PME#" error
		 */
		if (enable)
			call_platform_enable_wakeup(&dev->dev, 0);
		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)
{
	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.
 *
 *	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)
{
	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))
			goto err_out;
	}

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

	return 0;

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

/**
 * 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;