/*
 *	The PCI Library -- Direct Configuration access via i386 Ports
 *
 *	Copyright (c) 1997--2004 Martin Mares <mj@ucw.cz>
 *
 *	May 8, 2006 - Modified and ported to HelenOS by Jakub Jermar.
 *
 *	Can be freely distributed and used under the terms of the GNU GPL.
 */

#include <unistd.h>

#include "internal.h"

static inline void outb(u8 b, u16 port)
{
	asm volatile ("outb %0, %1\n" :: "a" (b), "d" (port));
}

static inline void outw(u16 w, u16 port)
{
	asm volatile ("outw %0, %1\n" :: "a" (w), "d" (port));
}

static inline void outl(u32 l, u16 port)
{
	asm volatile ("outl %0, %1\n" :: "a" (l), "d" (port));
}

static inline u8 inb(u16 port)
{
	u8 val;

	asm volatile ("inb %1, %0 \n" : "=a" (val) : "d"(port));
	return val;
}

static inline u16 inw(u16 port)
{
	u16 val;

	asm volatile ("inw %1, %0 \n" : "=a" (val) : "d"(port));
	return val;
}

static inline u32 inl(u16 port)
{
	u32 val;

	asm volatile ("inl %1, %0 \n" : "=a" (val) : "d"(port));
	return val;
}

static void conf12_init(struct pci_access *a)
{
}

static void conf12_cleanup(struct pci_access *a UNUSED)
{
}

/*
 * 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 intel_sanity_check(struct pci_access *a, struct pci_methods *m)
{
	struct pci_dev d;

	a->debug("...sanity check");
	d.bus = 0;
	d.func = 0;
	for (d.dev = 0; d.dev < 32; d.dev++) {
		u16 class, vendor;
		if (m->read(&d, PCI_CLASS_DEVICE, (byte *) & class,
			 sizeof(class))
		    && (class == cpu_to_le16(PCI_CLASS_BRIDGE_HOST)
			|| class == cpu_to_le16(PCI_CLASS_DISPLAY_VGA))
		    || m->read(&d, PCI_VENDOR_ID, (byte *) & vendor,
			       sizeof(vendor))
		    && (vendor == cpu_to_le16(PCI_VENDOR_ID_INTEL)
			|| vendor == cpu_to_le16(PCI_VENDOR_ID_COMPAQ))) {
			a->debug("...outside the Asylum at 0/%02x/0",
				 d.dev);
			return 1;
		}
	}
	a->debug("...insane");
	return 0;
}

/*
 *	Configuration type 1
 */

#define CONFIG_CMD(bus, device_fn, where)   (0x80000000 | (bus << 16) | (device_fn << 8) | (where & ~3))

static int conf1_detect(struct pci_access *a)
{
	unsigned int tmp;
	int res = 0;

	outb(0x01, 0xCFB);
	tmp = inl(0xCF8);
	outl(0x80000000, 0xCF8);
	if (inl(0xCF8) == 0x80000000)
		res = 1;
	outl(tmp, 0xCF8);
	if (res)
		res = intel_sanity_check(a, &pm_intel_conf1);
	return res;
}

static int conf1_read(struct pci_dev *d, int pos, byte * buf, int len)
{
	int addr = 0xcfc + (pos & 3);

	if (pos >= 256)
		return 0;

	outl(0x80000000 | ((d->bus & 0xff) << 16) |
	     (PCI_DEVFN(d->dev, d->func) << 8) | (pos & ~3), 0xcf8);

	switch (len) {
	case 1:
		buf[0] = inb(addr);
		break;
	case 2:
		((u16 *) buf)[0] = cpu_to_le16(inw(addr));
		break;
	case 4:
		((u32 *) buf)[0] = cpu_to_le32(inl(addr));
		break;
	default:
		return pci_generic_block_read(d, pos, buf, len);
	}
	return 1;
}

static int conf1_write(struct pci_dev *d, int pos, byte * buf, int len)
{
	int addr = 0xcfc + (pos & 3);

	if (pos >= 256)
		return 0;

	outl(0x80000000 | ((d->bus & 0xff) << 16) |
	     (PCI_DEVFN(d->dev, d->func) << 8) | (pos & ~3), 0xcf8);

	switch (len) {
	case 1:
		outb(buf[0], addr);
		break;
	case 2:
		outw(le16_to_cpu(((u16 *) buf)[0]), addr);
		break;
	case 4:
		outl(le32_to_cpu(((u32 *) buf)[0]), addr);
		break;
	default:
		return pci_generic_block_write(d, pos, buf, len);
	}
	return 1;
}

/*
 *	Configuration type 2. Obsolete and brain-damaged, but existing.
 */

static int conf2_detect(struct pci_access *a)
{
	/* This is ugly and tends to produce false positives. Beware. */
	outb(0x00, 0xCFB);
	outb(0x00, 0xCF8);
	outb(0x00, 0xCFA);
	if (inb(0xCF8) == 0x00 && inb(0xCFA) == 0x00)
		return intel_sanity_check(a, &pm_intel_conf2);
	else
		return 0;
}

static int conf2_read(struct pci_dev *d, int pos, byte * buf, int len)
{
	int addr = 0xc000 | (d->dev << 8) | pos;

	if (pos >= 256)
		return 0;

	if (d->dev >= 16)
		/* conf2 supports only 16 devices per bus */
		return 0;
	outb((d->func << 1) | 0xf0, 0xcf8);
	outb(d->bus, 0xcfa);
	switch (len) {
	case 1:
		buf[0] = inb(addr);
		break;
	case 2:
		((u16 *) buf)[0] = cpu_to_le16(inw(addr));
		break;
	case 4:
		((u32 *) buf)[0] = cpu_to_le32(inl(addr));
		break;
	default:
		outb(0, 0xcf8);
		return pci_generic_block_read(d, pos, buf, len);
	}
	outb(0, 0xcf8);
	return 1;
}

static int conf2_write(struct pci_dev *d, int pos, byte * buf, int len)
{
	int addr = 0xc000 | (d->dev << 8) | pos;

	if (pos >= 256)
		return 0;

	if (d->dev >= 16)
		d->access->error("conf2_write: only first 16 devices exist.");
	outb((d->func << 1) | 0xf0, 0xcf8);
	outb(d->bus, 0xcfa);
	switch (len) {
	case 1:
		outb(buf[0], addr);
		break;
	case 2:
		outw(le16_to_cpu(*(u16 *) buf), addr);
		break;
	case 4:
		outl(le32_to_cpu(*(u32 *) buf), addr);
		break;
	default:
		outb(0, 0xcf8);
		return pci_generic_block_write(d, pos, buf, len);
	}
	outb(0, 0xcf8);
	return 1;
}

struct pci_methods pm_intel_conf1 = {
	"Intel-conf1",
	NULL,			/* config */
	conf1_detect,
	conf12_init,
	conf12_cleanup,
	pci_generic_scan,
	pci_generic_fill_info,
	conf1_read,
	conf1_write,
	NULL,			/* init_dev */
	NULL			/* cleanup_dev */
};

struct pci_methods pm_intel_conf2 = {
	"Intel-conf2",
	NULL,			/* config */
	conf2_detect,
	conf12_init,
	conf12_cleanup,
	pci_generic_scan,
	pci_generic_fill_info,
	conf2_read,
	conf2_write,
	NULL,			/* init_dev */
	NULL			/* cleanup_dev */
};