pci.c

IXP425 平台下嵌入式LINUX的PCI总线的驱动程序

/*
 *	$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 <[e-mail]>
 */

#include <linux/config.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/pci.h>
#include <linux/string.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/ioport.h>
#include <linux/spinlock.h>
#include <linux/pm.h>
#include <linux/kmod.h>		/* for hotplug_path */
#include <linux/bitops.h>
#include <linux/delay.h>
#include <linux/cache.h>

#include <asm/page.h>
#include <asm/dma.h>	/* isa_dma_bridge_buggy */

#undef DEBUG

#ifdef DEBUG
#define DBG(x...) printk(x)
#else
#define DBG(x...)
#endif

LIST_HEAD(pci_root_buses);
LIST_HEAD(pci_devices);

/**
 * pci_find_slot - locate PCI device from a given PCI slot
 * @bus: number of PCI bus on which desired PCI device resides
 * @devfn: encodes number of PCI slot in which the desired PCI 
 * device resides and the logical device number within that slot 
 * in case of multi-function devices.
 *
 * Given a PCI bus and slot/function number, the desired PCI device 
 * is located in system global list of PCI devices.  If the device
 * is found, a pointer to its data structure is returned.  If no 
 * device is found, %NULL is returned.
 */
struct pci_dev *
pci_find_slot(unsigned int bus, unsigned int devfn)
{
	struct pci_dev *dev;

	pci_for_each_dev(dev) {
		if (dev->bus->number == bus && dev->devfn == devfn)
			return dev;
	}
	return NULL;
}

/**
 * pci_find_subsys - begin or continue searching for a PCI device by vendor/subvendor/device/subdevice id
 * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
 * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids
 * @ss_vendor: PCI subsystem vendor id to match, or %PCI_ANY_ID to match all vendor ids
 * @ss_device: PCI subsystem device id to match, or %PCI_ANY_ID to match all device ids
 * @from: Previous PCI device found in search, or %NULL for new search.
 *
 * Iterates through the list of known PCI devices.  If a PCI device is
 * found with a matching @vendor, @device, @ss_vendor and @ss_device, a pointer to its
 * device structure is returned.  Otherwise, %NULL is returned.
 * A new search is initiated by passing %NULL to the @from argument.
 * Otherwise if @from is not %NULL, searches continue from next device on the global list.
 */
struct pci_dev *
pci_find_subsys(unsigned int vendor, unsigned int device,
		unsigned int ss_vendor, unsigned int ss_device,
		const struct pci_dev *from)
{
	struct list_head *n = from ? from->global_list.next : pci_devices.next;

	while (n != &pci_devices) {
		struct pci_dev *dev = pci_dev_g(n);
		if ((vendor == PCI_ANY_ID || dev->vendor == vendor) &&
		    (device == PCI_ANY_ID || dev->device == device) &&
		    (ss_vendor == PCI_ANY_ID || dev->subsystem_vendor == ss_vendor) &&
		    (ss_device == PCI_ANY_ID || dev->subsystem_device == ss_device))
			return dev;
		n = n->next;
	}
	return NULL;
}


/**
 * pci_find_device - begin or continue searching for a PCI device by vendor/device id
 * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
 * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids
 * @from: Previous PCI device found in search, or %NULL for new search.
 *
 * Iterates through the list of known PCI devices.  If a PCI device is
 * found with a matching @vendor and @device, a pointer to its device structure is
 * returned.  Otherwise, %NULL is returned.
 * A new search is initiated by passing %NULL to the @from argument.
 * Otherwise if @from is not %NULL, searches continue from next device on the global list.
 */
struct pci_dev *
pci_find_device(unsigned int vendor, unsigned int device, const struct pci_dev *from)
{
	return pci_find_subsys(vendor, device, PCI_ANY_ID, PCI_ANY_ID, from);
}


/**
 * pci_find_class - begin or continue searching for a PCI device by class
 * @class: search for a PCI device with this class designation
 * @from: Previous PCI device found in search, or %NULL for new search.
 *
 * Iterates through the list of known PCI devices.  If a PCI device is
 * found with a matching @class, a pointer to its device structure is
 * returned.  Otherwise, %NULL is returned.
 * A new search is initiated by passing %NULL to the @from argument.
 * Otherwise if @from is not %NULL, searches continue from next device
 * on the global list.
 */
struct pci_dev *
pci_find_class(unsigned int class, const struct pci_dev *from)
{
	struct list_head *n = from ? from->global_list.next : pci_devices.next;

	while (n != &pci_devices) {
		struct pci_dev *dev = pci_dev_g(n);
		if (dev->class == class)
			return dev;
		n = n->next;
	}
	return NULL;
}

/**
 * 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 
 */
int
pci_find_capability(struct pci_dev *dev, int cap)
{
	u16 status;
	u8 pos, id;
	int ttl = 48;

	pci_read_config_word(dev, PCI_STATUS, &status);
	if (!(status & PCI_STATUS_CAP_LIST))
		return 0;
	switch (dev->hdr_type) {
	case PCI_HEADER_TYPE_NORMAL:
	case PCI_HEADER_TYPE_BRIDGE:
		pci_read_config_byte(dev, PCI_CAPABILITY_LIST, &pos);
		break;
	case PCI_HEADER_TYPE_CARDBUS:
		pci_read_config_byte(dev, PCI_CB_CAPABILITY_LIST, &pos);
		break;
	default:
		return 0;
	}
	while (ttl-- && pos >= 0x40) {
		pos &= ~3;
		pci_read_config_byte(dev, pos + PCI_CAP_LIST_ID, &id);
		if (id == 0xff)
			break;
		if (id == cap)
			return pos;
		pci_read_config_byte(dev, pos + PCI_CAP_LIST_NEXT, &pos);
	}
	return 0;
}


/**
 * 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<4; 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_set_power_state - Set the power state of a PCI device
 * @dev: PCI device to be suspended
 * @state: Power state 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, int state)
{
	int pm;
	u16 pmcsr;

	/* bound the state we're entering */
	if (state > 3) state = 3;

	/* 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 > 0 && dev->current_state > 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; 

	/* check if this device supports the desired state */
	if (state == 1 || state == 2) {
		u16 pmc;
		pci_read_config_word(dev,pm + PCI_PM_PMC,&pmc);
		if (state == 1 && !(pmc & PCI_PM_CAP_D1)) return -EIO;
		else if (state == 2 && !(pmc & PCI_PM_CAP_D2)) return -EIO;
	}

	/* If we're in D3, force entire word to 0.
	 * This doesn't affect PME_Status, disables PME_En, and
	 * sets PowerState to 0.
	 */
	if (dev->current_state >= 3)
		pmcsr = 0;
	else {
		pci_read_config_word(dev, pm + PCI_PM_CTRL, &pmcsr);
		pmcsr &= ~PCI_PM_CTRL_STATE_MASK;
		pmcsr |= state;
	}

	/* 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 == 3 || dev->current_state == 3)
	{
		set_current_state(TASK_UNINTERRUPTIBLE);
		schedule_timeout(HZ/100);
	}
	else if(state == 2 || dev->current_state == 2)
		udelay(200);
	dev->current_state = state;

	return 0;
}

/**
 * pci_save_state - save the PCI configuration space of a device before suspending
 * @dev: - PCI device that we're dealing with
 * @buffer: - buffer to hold config space context
 *
 * @buffer must be large enough to hold the entire PCI 2.2 config space 
 * (>= 64 bytes).
 */
int
pci_save_state(struct pci_dev *dev, u32 *buffer)
{
	int i;
	if (buffer) {
		/* XXX: 100% dword access ok here? */
		for (i = 0; i < 16; i++)
			pci_read_config_dword(dev, i * 4,&buffer[i]);
	}
	return 0;
}

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

	if (buffer) {
		for (i = 0; i < 16; i++)
			pci_write_config_dword(dev,i * 4, buffer[i]);
	}
	/*
	 * otherwise, write the context information we know from bootup.
	 * This works around a problem where warm-booting from Windows
	 * combined with a D3(hot)->D0 transition causes PCI config
	 * header data to be forgotten.
	 */	
	else {
		for (i = 0; i < 6; i ++)
			pci_write_config_dword(dev,
					       PCI_BASE_ADDRESS_0 + (i * 4),
					       dev->resource[i].start);
		pci_write_config_byte(dev, PCI_INTERRUPT_LINE, dev->irq);
	}
	return 0;
}

int 
pci_compare_state(struct pci_dev *dev, u32 *buffer)
{
	int i;
	unsigned int temp;

	if (buffer) {
		for (i = 0; i < 16; i++) {
			pci_read_config_dword(dev,i*4,&temp);
			if (temp!=buffer[i])
				return 1;
		}
	}
	return 0;
}

int pci_generic_suspend_save(struct pci_dev *pdev, u32 state)
{
	if (pdev)
		pci_save_state(pdev,pdev->saved_state);
	return 0;
}

int pci_generic_resume_restore(struct pci_dev *pdev)
{
	if (pdev)
		pci_restore_state(pdev,pdev->saved_state);
	return 0;		
}

int pci_generic_resume_compare(struct pci_dev *pdev)
{
	int retval=0;
	if (pdev)
		retval = pci_compare_state(pdev,pdev->saved_state);
	return retval;		
}

EXPORT_SYMBOL(pci_generic_suspend_save);
EXPORT_SYMBOL(pci_generic_resume_restore);
EXPORT_SYMBOL(pci_generic_resume_compare);

/**
 * 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;

	pci_set_power_state(dev, 0);
	if ((err = pcibios_enable_device(dev)) < 0)
		return err;
	return 0;
}

/**
 * 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;

	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);
	}
}

/**
 * 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, u32 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(value);   /* 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;

	pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &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_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++) {
		if (pci_resource_len(pdev, i) == 0)
			continue;

		if (pci_resource_flags(pdev, i) & IORESOURCE_IO)
			release_region(pci_resource_start(pdev, i),
				       pci_resource_len(pdev, i));

		else if (pci_resource_flags(pdev, i) & IORESOURCE_MEM)
			release_mem_region(pci_resource_start(pdev, i),
					   pci_resource_len(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.
 */