probe_roms.c

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#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/uaccess.h>
#include <linux/mmzone.h>
#include <linux/ioport.h>
#include <linux/seq_file.h>
#include <linux/console.h>
#include <linux/init.h>
#include <linux/edd.h>
#include <linux/dmi.h>
#include <linux/pfn.h>
#include <linux/pci.h>
#include <linux/export.h>

#include <asm/probe_roms.h>
#include <asm/pci-direct.h>
#include <asm/e820.h>
#include <asm/mmzone.h>
#include <asm/setup.h>
#include <asm/sections.h>
#include <asm/io.h>
#include <asm/setup_arch.h>

static struct resource system_rom_resource = {
    .name   = "System ROM",
    .start  = 0xf0000,
    .end    = 0xfffff,
    .flags  = IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
};

static struct resource extension_rom_resource = {
    .name   = "Extension ROM",
    .start  = 0xe0000,
    .end    = 0xeffff,
    .flags  = IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
};

static struct resource adapter_rom_resources[] = { {
    .name   = "Adapter ROM",
    .start  = 0xc8000,
    .end    = 0,
    .flags  = IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
}, {
    .name   = "Adapter ROM",
    .start  = 0,
    .end    = 0,
    .flags  = IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
}, {
    .name   = "Adapter ROM",
    .start  = 0,
    .end    = 0,
    .flags  = IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
}, {
    .name   = "Adapter ROM",
    .start  = 0,
    .end    = 0,
    .flags  = IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
}, {
    .name   = "Adapter ROM",
    .start  = 0,
    .end    = 0,
    .flags  = IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
}, {
    .name   = "Adapter ROM",
    .start  = 0,
    .end    = 0,
    .flags  = IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
} };

static struct resource video_rom_resource = {
    .name   = "Video ROM",
    .start  = 0xc0000,
    .end    = 0xc7fff,
    .flags  = IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
};

/* does this oprom support the given pci device, or any of the devices
 * that the driver supports?
 */
static bool match_id(struct pci_dev *pdev, unsigned short vendor, unsigned short device)
{
    struct pci_driver *drv = pdev->driver;
    const struct pci_device_id *id;

    if (pdev->vendor == vendor && pdev->device == device)
        return true;

    for (id = drv ? drv->id_table : NULL; id && id->vendor; id++)
        if (id->vendor == vendor && id->device == device)
            break;

    return id && id->vendor;
}

static bool probe_list(struct pci_dev *pdev, unsigned short vendor,
               const unsigned char *rom_list)
{
    unsigned short device;

    do {
        if (probe_kernel_address(rom_list, device) != 0)
            device = 0;

        if (device && match_id(pdev, vendor, device))
            break;

        rom_list += 2;
    } while (device);

    return !!device;
}

static struct resource *find_oprom(struct pci_dev *pdev)
{
    struct resource *oprom = NULL;
    int i;

    for (i = 0; i < ARRAY_SIZE(adapter_rom_resources); i++) {
        struct resource *res = &adapter_rom_resources[i];
        unsigned short offset, vendor, device, list, rev;
        const unsigned char *rom;

        if (res->end == 0)
            break;

        rom = isa_bus_to_virt(res->start);
        if (probe_kernel_address(rom + 0x18, offset) != 0)
            continue;

        if (probe_kernel_address(rom + offset + 0x4, vendor) != 0)
            continue;

        if (probe_kernel_address(rom + offset + 0x6, device) != 0)
            continue;

        if (match_id(pdev, vendor, device)) {
            oprom = res;
            break;
        }

        if (probe_kernel_address(rom + offset + 0x8, list) == 0 &&
            probe_kernel_address(rom + offset + 0xc, rev) == 0 &&
            rev >= 3 && list &&
            probe_list(pdev, vendor, rom + offset + list)) {
            oprom = res;
            break;
        }
    }

    return oprom;
}

void __iomem *pci_map_biosrom(struct pci_dev *pdev)
{
    struct resource *oprom = find_oprom(pdev);

    if (!oprom)
        return NULL;

    return ioremap(oprom->start, resource_size(oprom));
}
EXPORT_SYMBOL(pci_map_biosrom);

void pci_unmap_biosrom(void __iomem *image)
{
    iounmap(image);
}
EXPORT_SYMBOL(pci_unmap_biosrom);

size_t pci_biosrom_size(struct pci_dev *pdev)
{
    struct resource *oprom = find_oprom(pdev);

    return oprom ? resource_size(oprom) : 0;
}
EXPORT_SYMBOL(pci_biosrom_size);

#define ROMSIGNATURE 0xaa55

static int __init romsignature(const unsigned char *rom)
{
    const unsigned short * const ptr = (const unsigned short *)rom;
    unsigned short sig;

    return probe_kernel_address(ptr, sig) == 0 && sig == ROMSIGNATURE;
}

static int __init romchecksum(const unsigned char *rom, unsigned long length)
{
    unsigned char sum, c;

    for (sum = 0; length && probe_kernel_address(rom++, c) == 0; length--)
        sum += c;
    return !length && !sum;
}

void __init probe_roms(void)
{
    const unsigned char *rom;
    unsigned long start, length, upper;
    unsigned char c;
    int i;

    /* video rom */
    upper = adapter_rom_resources[0].start;
    for (start = video_rom_resource.start; start < upper; start += 2048) {
        rom = isa_bus_to_virt(start);
        if (!romsignature(rom))
            continue;

        video_rom_resource.start = start;

        if (probe_kernel_address(rom + 2, c) != 0)
            continue;

        /* 0 < length <= 0x7f * 512, historically */
        length = c * 512;

        /* if checksum okay, trust length byte */
        if (length && romchecksum(rom, length))
            video_rom_resource.end = start + length - 1;

        request_resource(&iomem_resource, &video_rom_resource);
        break;
    }

    start = (video_rom_resource.end + 1 + 2047) & ~2047UL;
    if (start < upper)
        start = upper;

    /* system rom */
    request_resource(&iomem_resource, &system_rom_resource);
    upper = system_rom_resource.start;

    /* check for extension rom (ignore length byte!) */
    rom = isa_bus_to_virt(extension_rom_resource.start);
    if (romsignature(rom)) {
        length = resource_size(&extension_rom_resource);
        if (romchecksum(rom, length)) {
            request_resource(&iomem_resource, &extension_rom_resource);
            upper = extension_rom_resource.start;
        }
    }

    /* check for adapter roms on 2k boundaries */
    for (i = 0; i < ARRAY_SIZE(adapter_rom_resources) && start < upper; start += 2048) {
        rom = isa_bus_to_virt(start);
        if (!romsignature(rom))
            continue;

        if (probe_kernel_address(rom + 2, c) != 0)
            continue;

        /* 0 < length <= 0x7f * 512, historically */
        length = c * 512;

        /* but accept any length that fits if checksum okay */
        if (!length || start + length > upper || !romchecksum(rom, length))
            continue;

        adapter_rom_resources[i].start = start;
        adapter_rom_resources[i].end = start + length - 1;
        request_resource(&iomem_resource, &adapter_rom_resources[i]);

        start = adapter_rom_resources[i++].end & ~2047UL;
    }
}