source: mainline/uspace/lib/libpci/i386-ports.c@ cf240cb

/*
 *      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 */
};