/*
 *	Low-Level PCI Support for PC
 *
 *	(c) 1999--2000 Martin Mares <mj@suse.cz>
 * 	2001 Andi Kleen. Cleanup for x86-64. Removed PCI-BIOS access and fixups
 *	for hardware that is unlikely to exist on any Hammer platform.
 * 
 * 	On x86-64 we don't have any access to the PCI-BIOS in long mode, so we
 *	cannot sort the pci device table based on what the BIOS did. This might 
 *	change the probing order of some devices compared to an i386 kernel.
 * 	It would be possible to fix this by moving some PCI BIOS access to very 
 * 	early boot; but I only want to do that if it is absolutely necessary because
 *	it is rather intrusive. An alternative might be to use ACPI here and 
 *	hope there is some correlation between the ACPI and PCI-BIOS tables.
 */

#include <linux/config.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/pci.h>
#include <linux/init.h>
#include <linux/ioport.h>

#include <asm/segment.h>
#include <asm/io.h>

#include "pci-x86_64.h"

unsigned int pci_probe = PCI_PROBE_BIOS | PCI_PROBE_CONF1 | PCI_PROBE_CONF2;

int pcibios_last_bus = -1;
struct pci_bus *pci_root_bus;
struct pci_ops *pci_root_ops;

/*
 * Direct access to PCI hardware...
 */

#ifdef CONFIG_PCI_DIRECT

/*
 * Functions for accessing PCI configuration space with type 1 accesses
 */

#define CONFIG_CMD(dev, where)   (0x80000000 | (dev->bus->number << 16) | (dev->devfn << 8) | (where & ~3))

static int pci_conf1_read_config_byte(struct pci_dev *dev, int where, u8 *value)
{
	outl(CONFIG_CMD(dev,where), 0xCF8);
	*value = inb(0xCFC + (where&3));
	return PCIBIOS_SUCCESSFUL;
}

static int pci_conf1_read_config_word(struct pci_dev *dev, int where, u16 *value)
{
	outl(CONFIG_CMD(dev,where), 0xCF8);    
	*value = inw(0xCFC + (where&2));
	return PCIBIOS_SUCCESSFUL;    
}

static int pci_conf1_read_config_dword(struct pci_dev *dev, int where, u32 *value)
{
	outl(CONFIG_CMD(dev,where), 0xCF8);
	*value = inl(0xCFC);
	return PCIBIOS_SUCCESSFUL;    
}

static int pci_conf1_write_config_byte(struct pci_dev *dev, int where, u8 value)
{
	outl(CONFIG_CMD(dev,where), 0xCF8);    
	outb(value, 0xCFC + (where&3));
	return PCIBIOS_SUCCESSFUL;
}

static int pci_conf1_write_config_word(struct pci_dev *dev, int where, u16 value)
{
	outl(CONFIG_CMD(dev,where), 0xCF8);
	outw(value, 0xCFC + (where&2));
	return PCIBIOS_SUCCESSFUL;
}

static int pci_conf1_write_config_dword(struct pci_dev *dev, int where, u32 value)
{
	outl(CONFIG_CMD(dev,where), 0xCF8);
	outl(value, 0xCFC);
	return PCIBIOS_SUCCESSFUL;
}

#undef CONFIG_CMD

static struct pci_ops pci_direct_conf1 = {
	pci_conf1_read_config_byte,
	pci_conf1_read_config_word,
	pci_conf1_read_config_dword,
	pci_conf1_write_config_byte,
	pci_conf1_write_config_word,
	pci_conf1_write_config_dword
};

/*
 * Functions for accessing PCI configuration space with type 2 accesses
 */

#define IOADDR(devfn, where)	((0xC000 | ((devfn & 0x78) << 5)) + where)
#define FUNC(devfn)		(((devfn & 7) << 1) | 0xf0)
#define SET(dev)		if (dev->devfn & 0x80) return PCIBIOS_DEVICE_NOT_FOUND;		\
				outb(FUNC(dev->devfn), 0xCF8);					\
				outb(dev->bus->number, 0xCFA);

static int pci_conf2_read_config_byte(struct pci_dev *dev, int where, u8 *value)
{
	SET(dev);
	*value = inb(IOADDR(dev->devfn,where));
	outb (0, 0xCF8);
	return PCIBIOS_SUCCESSFUL;
}

static int pci_conf2_read_config_word(struct pci_dev *dev, int where, u16 *value)
{
	SET(dev);
	*value = inw(IOADDR(dev->devfn,where));
	outb (0, 0xCF8);
	return PCIBIOS_SUCCESSFUL;
}

static int pci_conf2_read_config_dword(struct pci_dev *dev, int where, u32 *value)
{
	SET(dev);
	*value = inl (IOADDR(dev->devfn,where));    
	outb (0, 0xCF8);    
	return PCIBIOS_SUCCESSFUL;
}

static int pci_conf2_write_config_byte(struct pci_dev *dev, int where, u8 value)
{
	SET(dev);
	outb (value, IOADDR(dev->devfn,where));
	outb (0, 0xCF8);    
	return PCIBIOS_SUCCESSFUL;
}

static int pci_conf2_write_config_word(struct pci_dev *dev, int where, u16 value)
{
	SET(dev);
	outw (value, IOADDR(dev->devfn,where));
	outb (0, 0xCF8);    
	return PCIBIOS_SUCCESSFUL;
}

static int pci_conf2_write_config_dword(struct pci_dev *dev, int where, u32 value)
{
	SET(dev);
	outl (value, IOADDR(dev->devfn,where));    
	outb (0, 0xCF8);    
	return PCIBIOS_SUCCESSFUL;
}

#undef SET
#undef IOADDR
#undef FUNC

static struct pci_ops pci_direct_conf2 = {
	pci_conf2_read_config_byte,
	pci_conf2_read_config_word,
	pci_conf2_read_config_dword,
	pci_conf2_write_config_byte,
	pci_conf2_write_config_word,
	pci_conf2_write_config_dword
};

/*
 * Before we decide to use direct hardware access mechanisms, we try to do some
 * trivial checks to ensure it at least _seems_ to be working -- we just test
 * whether bus 00 contains a host bridge (this is similar to checking
 * techniques used in XFree86, but ours should be more reliable since we
 * attempt to make use of direct access hints provided by the PCI BIOS).
 *
 * This should be close to trivial, but it isn't, because there are buggy
 * chipsets (yes, you guessed it, by Intel and Compaq) that have no class ID.
 */
static int __init pci_sanity_check(struct pci_ops *o)
{
	u16 x;
	struct pci_bus bus;		/* Fake bus and device */
	struct pci_dev dev;

	if (pci_probe & PCI_NO_CHECKS)
		return 1;
	bus.number = 0;
	dev.bus = &bus;
	for(dev.devfn=0; dev.devfn < 0x100; dev.devfn++)
		if ((!o->read_word(&dev, PCI_CLASS_DEVICE, &x) &&
		     (x == PCI_CLASS_BRIDGE_HOST || x == PCI_CLASS_DISPLAY_VGA)) ||
		    (!o->read_word(&dev, PCI_VENDOR_ID, &x) &&
		     (x == PCI_VENDOR_ID_INTEL || x == PCI_VENDOR_ID_COMPAQ)))
			return 1;
	DBG("PCI: Sanity check failed\n");
	return 0;
}

static struct pci_ops * __init pci_check_direct(void)
{
	unsigned int tmp;
	unsigned long flags;

	__save_flags(flags); __cli();

	/*
	 * Check if configuration type 1 works.
	 */
	if (pci_probe & PCI_PROBE_CONF1) {
		outb (0x01, 0xCFB);
		tmp = inl (0xCF8);
		outl (0x80000000, 0xCF8);
		if (inl (0xCF8) == 0x80000000 &&
		    pci_sanity_check(&pci_direct_conf1)) {
			outl (tmp, 0xCF8);
			__restore_flags(flags);
			printk("PCI: Using configuration type 1\n");
			request_region(0xCF8, 8, "PCI conf1");
			return &pci_direct_conf1;
		}
		outl (tmp, 0xCF8);
	}

	/*
	 * Check if configuration type 2 works.
	 */
	if (pci_probe & PCI_PROBE_CONF2) {
		outb (0x00, 0xCFB);
		outb (0x00, 0xCF8);
		outb (0x00, 0xCFA);
		if (inb (0xCF8) == 0x00 && inb (0xCFA) == 0x00 &&
		    pci_sanity_check(&pci_direct_conf2)) {
			__restore_flags(flags);
			printk("PCI: Using configuration type 2\n");
			request_region(0xCF8, 4, "PCI conf2");
			return &pci_direct_conf2;
		}
	}

	__restore_flags(flags);
	return NULL;
}

#endif


/*
 * Several buggy motherboards address only 16 devices and mirror
 * them to next 16 IDs. We try to detect this `feature' on all
 * primary buses (those containing host bridges as they are
 * expected to be unique) and remove the ghost devices.
 */

static void __init pcibios_fixup_ghosts(struct pci_bus *b)
{
	struct list_head *ln, *mn;
	struct pci_dev *d, *e;
	int mirror = PCI_DEVFN(16,0);
	int seen_host_bridge = 0;
	int i;

	DBG("PCI: Scanning for ghost devices on bus %d\n", b->number);
	for (ln=b->devices.next; ln != &b->devices; ln=ln->next) {
		d = pci_dev_b(ln);
		if ((d->class >> 8) == PCI_CLASS_BRIDGE_HOST)
			seen_host_bridge++;
		for (mn=ln->next; mn != &b->devices; mn=mn->next) {
			e = pci_dev_b(mn);
			if (e->devfn != d->devfn + mirror ||
			    e->vendor != d->vendor ||
			    e->device != d->device ||
			    e->class != d->class)
				continue;
			for(i=0; i<PCI_NUM_RESOURCES; i++)
				if (e->resource[i].start != d->resource[i].start ||
				    e->resource[i].end != d->resource[i].end ||
				    e->resource[i].flags != d->resource[i].flags)
					continue;
			break;
		}
		if (mn == &b->devices)
			return;
	}
	if (!seen_host_bridge)
		return;
	printk("PCI: Ignoring ghost devices on bus %02x\n", b->number);

	ln = &b->devices;
	while (ln->next != &b->devices) {
		d = pci_dev_b(ln->next);
		if (d->devfn >= mirror) {
			list_del(&d->global_list);
			list_del(&d->bus_list);
			kfree(d);
		} else
			ln = ln->next;
	}
}

/*
 * Discover remaining PCI buses in case there are peer host bridges.
 * We use the number of last PCI bus provided by the PCI BIOS.
 */
static void __init pcibios_fixup_peer_bridges(void)
{
	int n;
	struct pci_bus bus;
	struct pci_dev dev;
	u16 l;

	if (pcibios_last_bus <= 0 || pcibios_last_bus >= 0xff)
		return;
	DBG("PCI: Peer bridge fixup\n");
	for (n=0; n <= pcibios_last_bus; n++) {
		if (pci_bus_exists(&pci_root_buses, n))
			continue;
		bus.number = n;
		bus.ops = pci_root_ops;
		dev.bus = &bus;
		for(dev.devfn=0; dev.devfn<256; dev.devfn += 8)
			if (!pci_read_config_word(&dev, PCI_VENDOR_ID, &l) &&
			    l != 0x0000 && l != 0xffff) {
				DBG("Found device at %02x:%02x [%04x]\n", n, dev.devfn, l);
				printk("PCI: Discovered peer bus %02x\n", n);
				pci_scan_bus(n, pci_root_ops, NULL);
				break;
			}
	}
}

struct pci_fixup pcibios_fixups[] = {
	/* Currently no fixup for hammer systems. May need to readd them
		as needed. */ 
	{ 0 }
};

/*
 *  Called after each bus is probed, but before its children
 *  are examined.
 */

void __init pcibios_fixup_bus(struct pci_bus *b)
{
	pcibios_fixup_ghosts(b);
	pci_read_bridge_bases(b);
}

/*
 * Initialization. Try all known PCI access methods. Note that we support
 * using both PCI BIOS and direct access: in such cases, we use I/O ports
 * to access config space, but we still keep BIOS order of cards to be
 * compatible with 2.0.X. This should go away some day.
 */

void __init pcibios_init(void)
{
	struct pci_ops *bios = NULL;
	struct pci_ops *dir = NULL;

#ifdef CONFIG_PCI_DIRECT
	if (pci_probe & (PCI_PROBE_CONF1 | PCI_PROBE_CONF2))
		dir = pci_check_direct();
#endif
	if (dir)
		pci_root_ops = dir;
	else if (bios)
		pci_root_ops = bios;
	else {
		printk("PCI: No PCI bus detected\n");
		return;
	}

	printk("PCI: Probing PCI hardware\n");
	pci_root_bus = pci_scan_bus(0, pci_root_ops, NULL);

	pcibios_irq_init();
	pcibios_fixup_peer_bridges();
	pcibios_fixup_irqs();
	pcibios_resource_survey();

}

char * __init pcibios_setup(char *str)
{
	if (!strcmp(str, "off")) {
		pci_probe = 0;
		return NULL;
	}
	else if (!strncmp(str, "bios", 4)) {
		printk("PCI: No PCI bios access on x86-64. BIOS hint ignored.\n");
		return NULL;
	} else if (!strcmp(str, "nobios")) {
		pci_probe &= ~PCI_PROBE_BIOS;
		return NULL;
	} else if (!strcmp(str, "nosort")) { /* Default */ 
		pci_probe |= PCI_NO_SORT;
		return NULL;
	} 
#ifdef CONFIG_PCI_DIRECT
	else if (!strcmp(str, "conf1")) {
		pci_probe = PCI_PROBE_CONF1 | PCI_NO_CHECKS;
		return NULL;
	}
	else if (!strcmp(str, "conf2")) {
		pci_probe = PCI_PROBE_CONF2 | PCI_NO_CHECKS;
		return NULL;
	}
#endif
	else if (!strcmp(str, "rom")) {
		pci_probe |= PCI_ASSIGN_ROMS;
		return NULL;
	} else if (!strcmp(str, "assign-busses")) {
		pci_probe |= PCI_ASSIGN_ALL_BUSSES;
		return NULL;
	} else if (!strncmp(str, "irqmask=", 8)) {
		pcibios_irq_mask = simple_strtol(str+8, NULL, 0);
		return NULL;
	} else if (!strncmp(str, "lastbus=", 8)) {
		pcibios_last_bus = simple_strtol(str+8, NULL, 0);
		return NULL;
	}
	return str;
}

unsigned int pcibios_assign_all_busses(void)
{
	return (pci_probe & PCI_ASSIGN_ALL_BUSSES) ? 1 : 0;
}

int pcibios_enable_device(struct pci_dev *dev)
{
	int err;

	if ((err = pcibios_enable_resources(dev)) < 0)
		return err;
	pcibios_enable_irq(dev);
	return 0;
}
