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 (readb(image) != 0x55) {
  81                         dev_err(&pdev->dev, "Invalid ROM contents\n");
  82                         break;
  83                 }
  84                 if (readb(image + 1) != 0xAA)
  85                         break;
  86                 /* get the PCI data structure and check its signature */
  87                 pds = image + readw(image + 24);
  88                 if (readb(pds) != 'P')
  89                         break;
  90                 if (readb(pds + 1) != 'C')
  91                         break;
  92                 if (readb(pds + 2) != 'I')
  93                         break;
  94                 if (readb(pds + 3) != 'R')
  95                         break;
  96                 last_image = readb(pds + 21) & 0x80;
  97                 length = readw(pds + 16);
  98                 image += length * 512;
  99         } while (length && !last_image);
 100
 101         /* never return a size larger than the PCI resource window */
 102         /* there are known ROMs that get the size wrong */
 103         return min((size_t)(image - rom), size);
 104 }
 105
 106 /**
 107  * pci_map_rom - map a PCI ROM to kernel space
 108  * @pdev: pointer to pci device struct
 109  * @size: pointer to receive size of pci window over ROM
 110  *
 111  * Return: kernel virtual pointer to image of ROM
 112  *
 113  * Map a PCI ROM into kernel space. If ROM is boot video ROM,
 114  * the shadow BIOS copy will be returned instead of the
 115  * actual ROM.
 116  */
 117 void __iomem *pci_map_rom(struct pci_dev *pdev, size_t *size)
 118 {
 119         struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
 120         loff_t start;
 121         void __iomem *rom;
 122
 123         /*
 124          * IORESOURCE_ROM_SHADOW set on x86, x86_64 and IA64 supports legacy
 125          * memory map if the VGA enable bit of the Bridge Control register is
 126          * set for embedded VGA.
 127          */
 128         if (res->flags & IORESOURCE_ROM_SHADOW) {
 129                 /* primary video rom always starts here */
 130                 start = (loff_t)0xC0000;
 131                 *size = 0x20000; /* cover C000:0 through E000:0 */
 132         } else {
 133                 if (res->flags &
 134                         (IORESOURCE_ROM_COPY | IORESOURCE_ROM_BIOS_COPY)) {
 135                         *size = pci_resource_len(pdev, PCI_ROM_RESOURCE);
 136                         return (void __iomem *)(unsigned long)
 137                                 pci_resource_start(pdev, PCI_ROM_RESOURCE);
 138                 } else {
 139                         /* assign the ROM an address if it doesn't have one */
 140                         if (res->parent == NULL &&
 141                             pci_assign_resource(pdev, PCI_ROM_RESOURCE))
 142                                 return NULL;
 143                         start = pci_resource_start(pdev, PCI_ROM_RESOURCE);
 144                         *size = pci_resource_len(pdev, PCI_ROM_RESOURCE);
 145                         if (*size == 0)
 146                                 return NULL;
 147
 148                         /* Enable ROM space decodes */
 149                         if (pci_enable_rom(pdev))
 150                                 return NULL;
 151                 }
 152         }
 153
 154         rom = ioremap(start, *size);
 155         if (!rom) {
 156                 /* restore enable if ioremap fails */
 157                 if (!(res->flags & (IORESOURCE_ROM_ENABLE |
 158                                     IORESOURCE_ROM_SHADOW |
 159                                     IORESOURCE_ROM_COPY)))
 160                         pci_disable_rom(pdev);
 161                 return NULL;
 162         }
 163
 164         /*
 165          * Try to find the true size of the ROM since sometimes the PCI window
 166          * size is much larger than the actual size of the ROM.
 167          * True size is important if the ROM is going to be copied.
 168          */
 169         *size = pci_get_rom_size(pdev, rom, *size);
 170         return rom;
 171 }
 172 EXPORT_SYMBOL(pci_map_rom);
 173
 174 /**
 175  * pci_unmap_rom - unmap the ROM from kernel space
 176  * @pdev: pointer to pci device struct
 177  * @rom: virtual address of the previous mapping
 178  *
 179  * Remove a mapping of a previously mapped ROM
 180  */
 181 void pci_unmap_rom(struct pci_dev *pdev, void __iomem *rom)
 182 {
 183         struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
 184
 185         if (res->flags & (IORESOURCE_ROM_COPY | IORESOURCE_ROM_BIOS_COPY))
 186                 return;
 187
 188         iounmap(rom);
 189
 190         /* Disable again before continuing, leave enabled if pci=rom */
 191         if (!(res->flags & (IORESOURCE_ROM_ENABLE | IORESOURCE_ROM_SHADOW)))
 192                 pci_disable_rom(pdev);
 193 }
 194 EXPORT_SYMBOL(pci_unmap_rom);
 195
 196 /**
 197  * pci_cleanup_rom - free the ROM copy created by pci_map_rom_copy
 198  * @pdev: pointer to pci device struct
 199  *
 200  * Free the copied ROM if we allocated one.
 201  */
 202 void pci_cleanup_rom(struct pci_dev *pdev)
 203 {
 204         struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
 205
 206         if (res->flags & IORESOURCE_ROM_COPY) {
 207                 kfree((void *)(unsigned long)res->start);
 208                 res->flags |= IORESOURCE_UNSET;
 209                 res->flags &= ~IORESOURCE_ROM_COPY;
 210                 res->start = 0;
 211                 res->end = 0;
 212         }
 213 }
 214
 215 /**
 216  * pci_platform_rom - provides a pointer to any ROM image provided by the
 217  * platform
 218  * @pdev: pointer to pci device struct
 219  * @size: pointer to receive size of pci window over ROM
 220  */
 221 void __iomem *pci_platform_rom(struct pci_dev *pdev, size_t *size)
 222 {
 223         if (pdev->rom && pdev->romlen) {
 224                 *size = pdev->romlen;
 225                 return phys_to_virt((phys_addr_t)pdev->rom);
 226         }
 227
 228         return NULL;
 229 }
 230 EXPORT_SYMBOL(pci_platform_rom);