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  */
  25 int 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         pcibios_resource_to_bus(pdev->bus, &region, res);
  35         pci_read_config_dword(pdev, pdev->rom_base_reg, &rom_addr);
  36         rom_addr &= ~PCI_ROM_ADDRESS_MASK;
  37         rom_addr |= region.start | PCI_ROM_ADDRESS_ENABLE;
  38         pci_write_config_dword(pdev, pdev->rom_base_reg, rom_addr);
  39         return 0;
  40 }
  41 EXPORT_SYMBOL_GPL(pci_enable_rom);
  42
  43 /**
  44  * pci_disable_rom - disable ROM decoding for a PCI device
  45  * @pdev: PCI device to disable
  46  *
  47  * Disable ROM decoding on a PCI device by turning off the last bit in the
  48  * ROM BAR.
  49  */
  50 void pci_disable_rom(struct pci_dev *pdev)
  51 {
  52         u32 rom_addr;
  53         pci_read_config_dword(pdev, pdev->rom_base_reg, &rom_addr);
  54         rom_addr &= ~PCI_ROM_ADDRESS_ENABLE;
  55         pci_write_config_dword(pdev, pdev->rom_base_reg, rom_addr);
  56 }
  57 EXPORT_SYMBOL_GPL(pci_disable_rom);
  58
  59 /**
  60  * pci_get_rom_size - obtain the actual size of the ROM image
  61  * @pdev: target PCI device
  62  * @rom: kernel virtual pointer to image of ROM
  63  * @size: size of PCI window
  64  *  return: size of actual ROM image
  65  *
  66  * Determine the actual length of the ROM image.
  67  * The PCI window size could be much larger than the
  68  * actual image size.
  69  */
  70 size_t pci_get_rom_size(struct pci_dev *pdev, void __iomem *rom, size_t size)
  71 {
  72         void __iomem *image;
  73         int last_image;
  74         unsigned length;
  75
  76         image = rom;
  77         do {
  78                 void __iomem *pds;
  79                 /* Standard PCI ROMs start out with these bytes 55 AA */
  80                 if (readw(image) != 0xAA55) {
  81                         dev_err(&pdev->dev, "Invalid PCI ROM header signature: expecting 0xaa55, got %#06x\n",
  82                                 readw(image));
  83                         break;
  84                 }
  85                 /* get the PCI data structure and check its "PCIR" signature */
  86                 pds = image + readw(image + 24);
  87                 if (readl(pds) != 0x52494350) {
  88                         dev_err(&pdev->dev, "Invalid PCI ROM data signature: expecting 0x52494350, got %#010x\n",
  89                                 readl(pds));
  90                         break;
  91                 }
  92                 last_image = readb(pds + 21) & 0x80;
  93                 length = readw(pds + 16);
  94                 image += length * 512;
  95         } while (length && !last_image);
  96
  97         /* never return a size larger than the PCI resource window */
  98         /* there are known ROMs that get the size wrong */
  99         return min((size_t)(image - rom), size);
 100 }
 101
 102 /**
 103  * pci_map_rom - map a PCI ROM to kernel space
 104  * @pdev: pointer to pci device struct
 105  * @size: pointer to receive size of pci window over ROM
 106  *
 107  * Return: kernel virtual pointer to image of ROM
 108  *
 109  * Map a PCI ROM into kernel space. If ROM is boot video ROM,
 110  * the shadow BIOS copy will be returned instead of the
 111  * actual ROM.
 112  */
 113 void __iomem *pci_map_rom(struct pci_dev *pdev, size_t *size)
 114 {
 115         struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
 116         loff_t start;
 117         void __iomem *rom;
 118
 119         /*
 120          * IORESOURCE_ROM_SHADOW set on x86, x86_64 and IA64 supports legacy
 121          * memory map if the VGA enable bit of the Bridge Control register is
 122          * set for embedded VGA.
 123          */
 124         if (res->flags & IORESOURCE_ROM_SHADOW) {
 125                 /* primary video rom always starts here */
 126                 start = (loff_t)0xC0000;
 127                 *size = 0x20000; /* cover C000:0 through E000:0 */
 128         } else {
 129                 if (res->flags &
 130                         (IORESOURCE_ROM_COPY | IORESOURCE_ROM_BIOS_COPY)) {
 131                         *size = pci_resource_len(pdev, PCI_ROM_RESOURCE);
 132                         return (void __iomem *)(unsigned long)
 133                                 pci_resource_start(pdev, PCI_ROM_RESOURCE);
 134                 } else {
 135                         /* assign the ROM an address if it doesn't have one */
 136                         if (res->parent == NULL &&
 137                             pci_assign_resource(pdev, PCI_ROM_RESOURCE))
 138                                 return NULL;
 139                         start = pci_resource_start(pdev, PCI_ROM_RESOURCE);
 140                         *size = pci_resource_len(pdev, PCI_ROM_RESOURCE);
 141                         if (*size == 0)
 142                                 return NULL;
 143
 144                         /* Enable ROM space decodes */
 145                         if (pci_enable_rom(pdev))
 146                                 return NULL;
 147                 }
 148         }
 149
 150         rom = ioremap(start, *size);
 151         if (!rom) {
 152                 /* restore enable if ioremap fails */
 153                 if (!(res->flags & (IORESOURCE_ROM_ENABLE |
 154                                     IORESOURCE_ROM_SHADOW |
 155                                     IORESOURCE_ROM_COPY)))
 156                         pci_disable_rom(pdev);
 157                 return NULL;
 158         }
 159
 160         /*
 161          * Try to find the true size of the ROM since sometimes the PCI window
 162          * size is much larger than the actual size of the ROM.
 163          * True size is important if the ROM is going to be copied.
 164          */
 165         *size = pci_get_rom_size(pdev, rom, *size);
 166         return rom;
 167 }
 168 EXPORT_SYMBOL(pci_map_rom);
 169
 170 /**
 171  * pci_unmap_rom - unmap the ROM from kernel space
 172  * @pdev: pointer to pci device struct
 173  * @rom: virtual address of the previous mapping
 174  *
 175  * Remove a mapping of a previously mapped ROM
 176  */
 177 void pci_unmap_rom(struct pci_dev *pdev, void __iomem *rom)
 178 {
 179         struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
 180
 181         if (res->flags & (IORESOURCE_ROM_COPY | IORESOURCE_ROM_BIOS_COPY))
 182                 return;
 183
 184         iounmap(rom);
 185
 186         /* Disable again before continuing, leave enabled if pci=rom */
 187         if (!(res->flags & (IORESOURCE_ROM_ENABLE | IORESOURCE_ROM_SHADOW)))
 188                 pci_disable_rom(pdev);
 189 }
 190 EXPORT_SYMBOL(pci_unmap_rom);
 191
 192 /**
 193  * pci_cleanup_rom - free the ROM copy created by pci_map_rom_copy
 194  * @pdev: pointer to pci device struct
 195  *
 196  * Free the copied ROM if we allocated one.
 197  */
 198 void pci_cleanup_rom(struct pci_dev *pdev)
 199 {
 200         struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
 201
 202         if (res->flags & IORESOURCE_ROM_COPY) {
 203                 kfree((void *)(unsigned long)res->start);
 204                 res->flags |= IORESOURCE_UNSET;
 205                 res->flags &= ~IORESOURCE_ROM_COPY;
 206                 res->start = 0;
 207                 res->end = 0;
 208         }
 209 }
 210
 211 /**
 212  * pci_platform_rom - provides a pointer to any ROM image provided by the
 213  * platform
 214  * @pdev: pointer to pci device struct
 215  * @size: pointer to receive size of pci window over ROM
 216  */
 217 void __iomem *pci_platform_rom(struct pci_dev *pdev, size_t *size)
 218 {
 219         if (pdev->rom && pdev->romlen) {
 220                 *size = pdev->romlen;
 221                 return phys_to_virt((phys_addr_t)pdev->rom);
 222         }
 223
 224         return NULL;
 225 }
 226 EXPORT_SYMBOL(pci_platform_rom);