rom.c

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/*
 * drivers/pci/rom.c
 *
 * (C) Copyright 2004 Jon Smirl <[email protected]>
 * (C) Copyright 2004 Silicon Graphics, Inc. Jesse Barnes <[email protected]>
 *
 * PCI ROM access routines
 */
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/pci.h>
#include <linux/slab.h>

#include "pci.h"

int pci_enable_rom(struct pci_dev *pdev)
{
    struct resource *res = pdev->resource + PCI_ROM_RESOURCE;
    struct pci_bus_region region;
    u32 rom_addr;

    if (!res->flags)
        return -1;

    pcibios_resource_to_bus(pdev, &region, res);
    pci_read_config_dword(pdev, pdev->rom_base_reg, &rom_addr);
    rom_addr &= ~PCI_ROM_ADDRESS_MASK;
    rom_addr |= region.start | PCI_ROM_ADDRESS_ENABLE;
    pci_write_config_dword(pdev, pdev->rom_base_reg, rom_addr);
    return 0;
}

void pci_disable_rom(struct pci_dev *pdev)
{
    u32 rom_addr;
    pci_read_config_dword(pdev, pdev->rom_base_reg, &rom_addr);
    rom_addr &= ~PCI_ROM_ADDRESS_ENABLE;
    pci_write_config_dword(pdev, pdev->rom_base_reg, rom_addr);
}

size_t pci_get_rom_size(struct pci_dev *pdev, void __iomem *rom, size_t size)
{
    void __iomem *image;
    int last_image;

    image = rom;
    do {
        void __iomem *pds;
        /* Standard PCI ROMs start out with these bytes 55 AA */
        if (readb(image) != 0x55) {
            dev_err(&pdev->dev, "Invalid ROM contents\n");
            break;
        }
        if (readb(image + 1) != 0xAA)
            break;
        /* get the PCI data structure and check its signature */
        pds = image + readw(image + 24);
        if (readb(pds) != 'P')
            break;
        if (readb(pds + 1) != 'C')
            break;
        if (readb(pds + 2) != 'I')
            break;
        if (readb(pds + 3) != 'R')
            break;
        last_image = readb(pds + 21) & 0x80;
        /* this length is reliable */
        image += readw(pds + 16) * 512;
    } while (!last_image);

    /* never return a size larger than the PCI resource window */
    /* there are known ROMs that get the size wrong */
    return min((size_t)(image - rom), size);
}

void __iomem *pci_map_rom(struct pci_dev *pdev, size_t *size)
{
    struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
    loff_t start;
    void __iomem *rom;

    /*
     * IORESOURCE_ROM_SHADOW set on x86, x86_64 and IA64 supports legacy
     * memory map if the VGA enable bit of the Bridge Control register is
     * set for embedded VGA.
     */
    if (res->flags & IORESOURCE_ROM_SHADOW) {
        /* primary video rom always starts here */
        start = (loff_t)0xC0000;
        *size = 0x20000; /* cover C000:0 through E000:0 */
    } else {
        if (res->flags &
            (IORESOURCE_ROM_COPY | IORESOURCE_ROM_BIOS_COPY)) {
            *size = pci_resource_len(pdev, PCI_ROM_RESOURCE);
            return (void __iomem *)(unsigned long)
                pci_resource_start(pdev, PCI_ROM_RESOURCE);
        } else {
            /* assign the ROM an address if it doesn't have one */
            if (res->parent == NULL &&
                pci_assign_resource(pdev,PCI_ROM_RESOURCE))
                return NULL;
            start = pci_resource_start(pdev, PCI_ROM_RESOURCE);
            *size = pci_resource_len(pdev, PCI_ROM_RESOURCE);
            if (*size == 0)
                return NULL;

            /* Enable ROM space decodes */
            if (pci_enable_rom(pdev))
                return NULL;
        }
    }

    rom = ioremap(start, *size);
    if (!rom) {
        /* restore enable if ioremap fails */
        if (!(res->flags & (IORESOURCE_ROM_ENABLE |
                    IORESOURCE_ROM_SHADOW |
                    IORESOURCE_ROM_COPY)))
            pci_disable_rom(pdev);
        return NULL;
    }

    /*
     * Try to find the true size of the ROM since sometimes the PCI window
     * size is much larger than the actual size of the ROM.
     * True size is important if the ROM is going to be copied.
     */
    *size = pci_get_rom_size(pdev, rom, *size);
    return rom;
}

void pci_unmap_rom(struct pci_dev *pdev, void __iomem *rom)
{
    struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];

    if (res->flags & (IORESOURCE_ROM_COPY | IORESOURCE_ROM_BIOS_COPY))
        return;

    iounmap(rom);

    /* Disable again before continuing, leave enabled if pci=rom */
    if (!(res->flags & (IORESOURCE_ROM_ENABLE | IORESOURCE_ROM_SHADOW)))
        pci_disable_rom(pdev);
}

void pci_cleanup_rom(struct pci_dev *pdev)
{
    struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
    if (res->flags & IORESOURCE_ROM_COPY) {
        kfree((void*)(unsigned long)res->start);
        res->flags &= ~IORESOURCE_ROM_COPY;
        res->start = 0;
        res->end = 0;
    }
}

EXPORT_SYMBOL(pci_map_rom);
EXPORT_SYMBOL(pci_unmap_rom);
EXPORT_SYMBOL_GPL(pci_enable_rom);
EXPORT_SYMBOL_GPL(pci_disable_rom);