LXR linux/drivers/pci/rom.c

   1/*
   2 * drivers/pci/rom.c
   3 *
   4 * (C) Copyright 2004 Jon Smirl <jonsmirl@yahoo.com>
   5 * (C) Copyright 2004 Silicon Graphics, Inc. Jesse Barnes <jbarnes@sgi.com>
   6 *
   7 * PCI ROM access routines
   8 */
   9#include <linux/kernel.h>
  10#include <linux/export.h>
  11#include <linux/pci.h>
  12#include <linux/slab.h>
  13
  14#include "pci.h"
  15
  16/**
  17 * pci_enable_rom - enable ROM decoding for a PCI device
  18 * @pdev: PCI device to enable
  19 *
  20 * Enable ROM decoding on @dev.  This involves simply turning on the last
  21 * bit of the PCI ROM BAR.  Note that some cards may share address decoders
  22 * between the ROM and other resources, so enabling it may disable access
  23 * to MMIO registers or other card memory.
  24 */
  25int pci_enable_rom(struct pci_dev *pdev)
  26{
  27        struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
  28        struct pci_bus_region region;
  29        u32 rom_addr;
  30
  31        if (!res->flags)
  32                return -1;
  33
  34        /* Nothing to enable if we're using a shadow copy in RAM */
  35        if (res->flags & IORESOURCE_ROM_SHADOW)
  36                return 0;
  37
  38        pcibios_resource_to_bus(pdev->bus, &region, res);
  39        pci_read_config_dword(pdev, pdev->rom_base_reg, &rom_addr);
  40        rom_addr &= ~PCI_ROM_ADDRESS_MASK;
  41        rom_addr |= region.start | PCI_ROM_ADDRESS_ENABLE;
  42        pci_write_config_dword(pdev, pdev->rom_base_reg, rom_addr);
  43        return 0;
  44}
  45EXPORT_SYMBOL_GPL(pci_enable_rom);
  46
  47/**
  48 * pci_disable_rom - disable ROM decoding for a PCI device
  49 * @pdev: PCI device to disable
  50 *
  51 * Disable ROM decoding on a PCI device by turning off the last bit in the
  52 * ROM BAR.
  53 */
  54void pci_disable_rom(struct pci_dev *pdev)
  55{
  56        struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
  57        u32 rom_addr;
  58
  59        if (res->flags & IORESOURCE_ROM_SHADOW)
  60                return;
  61
  62        pci_read_config_dword(pdev, pdev->rom_base_reg, &rom_addr);
  63        rom_addr &= ~PCI_ROM_ADDRESS_ENABLE;
  64        pci_write_config_dword(pdev, pdev->rom_base_reg, rom_addr);
  65}
  66EXPORT_SYMBOL_GPL(pci_disable_rom);
  67
  68/**
  69 * pci_get_rom_size - obtain the actual size of the ROM image
  70 * @pdev: target PCI device
  71 * @rom: kernel virtual pointer to image of ROM
  72 * @size: size of PCI window
  73 *  return: size of actual ROM image
  74 *
  75 * Determine the actual length of the ROM image.
  76 * The PCI window size could be much larger than the
  77 * actual image size.
  78 */
  79size_t pci_get_rom_size(struct pci_dev *pdev, void __iomem *rom, size_t size)
  80{
  81        void __iomem *image;
  82        int last_image;
  83        unsigned length;
  84
  85        image = rom;
  86        do {
  87                void __iomem *pds;
  88                /* Standard PCI ROMs start out with these bytes 55 AA */
  89                if (readw(image) != 0xAA55) {
  90                        dev_err(&pdev->dev, "Invalid PCI ROM header signature: expecting 0xaa55, got %#06x\n",
  91                                readw(image));
  92                        break;
  93                }
  94                /* get the PCI data structure and check its "PCIR" signature */
  95                pds = image + readw(image + 24);
  96                if (readl(pds) != 0x52494350) {
  97                        dev_err(&pdev->dev, "Invalid PCI ROM data signature: expecting 0x52494350, got %#010x\n",
  98                                readl(pds));
  99                        break;
 100                }
 101                last_image = readb(pds + 21) & 0x80;
 102                length = readw(pds + 16);
 103                image += length * 512;
 104                /* Avoid iterating through memory outside the resource window */
 105                if (image > rom + size)
 106                        break;
 107        } while (length && !last_image);
 108
 109        /* never return a size larger than the PCI resource window */
 110        /* there are known ROMs that get the size wrong */
 111        return min((size_t)(image - rom), size);
 112}
 113
 114/**
 115 * pci_map_rom - map a PCI ROM to kernel space
 116 * @pdev: pointer to pci device struct
 117 * @size: pointer to receive size of pci window over ROM
 118 *
 119 * Return: kernel virtual pointer to image of ROM
 120 *
 121 * Map a PCI ROM into kernel space. If ROM is boot video ROM,
 122 * the shadow BIOS copy will be returned instead of the
 123 * actual ROM.
 124 */
 125void __iomem *pci_map_rom(struct pci_dev *pdev, size_t *size)
 126{
 127        struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
 128        loff_t start;
 129        void __iomem *rom;
 130
 131        /* assign the ROM an address if it doesn't have one */
 132        if (res->parent == NULL && pci_assign_resource(pdev, PCI_ROM_RESOURCE))
 133                return NULL;
 134
 135        start = pci_resource_start(pdev, PCI_ROM_RESOURCE);
 136        *size = pci_resource_len(pdev, PCI_ROM_RESOURCE);
 137        if (*size == 0)
 138                return NULL;
 139
 140        /* Enable ROM space decodes */
 141        if (pci_enable_rom(pdev))
 142                return NULL;
 143
 144        rom = ioremap(start, *size);
 145        if (!rom) {
 146                /* restore enable if ioremap fails */
 147                if (!(res->flags & IORESOURCE_ROM_ENABLE))
 148                        pci_disable_rom(pdev);
 149                return NULL;
 150        }
 151
 152        /*
 153         * Try to find the true size of the ROM since sometimes the PCI window
 154         * size is much larger than the actual size of the ROM.
 155         * True size is important if the ROM is going to be copied.
 156         */
 157        *size = pci_get_rom_size(pdev, rom, *size);
 158        return rom;
 159}
 160EXPORT_SYMBOL(pci_map_rom);
 161
 162/**
 163 * pci_unmap_rom - unmap the ROM from kernel space
 164 * @pdev: pointer to pci device struct
 165 * @rom: virtual address of the previous mapping
 166 *
 167 * Remove a mapping of a previously mapped ROM
 168 */
 169void pci_unmap_rom(struct pci_dev *pdev, void __iomem *rom)
 170{
 171        struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
 172
 173        iounmap(rom);
 174
 175        /* Disable again before continuing */
 176        if (!(res->flags & IORESOURCE_ROM_ENABLE))
 177                pci_disable_rom(pdev);
 178}
 179EXPORT_SYMBOL(pci_unmap_rom);
 180
 181/**
 182 * pci_platform_rom - provides a pointer to any ROM image provided by the
 183 * platform
 184 * @pdev: pointer to pci device struct
 185 * @size: pointer to receive size of pci window over ROM
 186 */
 187void __iomem *pci_platform_rom(struct pci_dev *pdev, size_t *size)
 188{
 189        if (pdev->rom && pdev->romlen) {
 190                *size = pdev->romlen;
 191                return phys_to_virt((phys_addr_t)pdev->rom);
 192        }
 193
 194        return NULL;
 195}
 196EXPORT_SYMBOL(pci_platform_rom);
 197