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/pci.h>
  11 #include <linux/slab.h>
  12
  13 #include "pci.h"
  14
  15 /**
  16  * pci_enable_rom - enable ROM decoding for a PCI device
  17  * @pdev: PCI device to enable
  18  *
  19  * Enable ROM decoding on @dev.  This involves simply turning on the last
  20  * bit of the PCI ROM BAR.  Note that some cards may share address decoders
  21  * between the ROM and other resources, so enabling it may disable access
  22  * to MMIO registers or other card memory.
  23  */
  24 static int pci_enable_rom(struct pci_dev *pdev)
  25 {
  26         struct resource *res = pdev->resource + PCI_ROM_RESOURCE;
  27         struct pci_bus_region region;
  28         u32 rom_addr;
  29
  30         if (!res->flags)
  31                 return -1;
  32
  33         pcibios_resource_to_bus(pdev, &region, res);
  34         pci_read_config_dword(pdev, pdev->rom_base_reg, &rom_addr);
  35         rom_addr &= ~PCI_ROM_ADDRESS_MASK;
  36         rom_addr |= region.start | PCI_ROM_ADDRESS_ENABLE;
  37         pci_write_config_dword(pdev, pdev->rom_base_reg, rom_addr);
  38         return 0;
  39 }
  40
  41 /**
  42  * pci_disable_rom - disable ROM decoding for a PCI device
  43  * @pdev: PCI device to disable
  44  *
  45  * Disable ROM decoding on a PCI device by turning off the last bit in the
  46  * ROM BAR.
  47  */
  48 static void pci_disable_rom(struct pci_dev *pdev)
  49 {
  50         u32 rom_addr;
  51         pci_read_config_dword(pdev, pdev->rom_base_reg, &rom_addr);
  52         rom_addr &= ~PCI_ROM_ADDRESS_ENABLE;
  53         pci_write_config_dword(pdev, pdev->rom_base_reg, rom_addr);
  54 }
  55
  56 /**
  57  * pci_get_rom_size - obtain the actual size of the ROM image
  58  * @rom: kernel virtual pointer to image of ROM
  59  * @size: size of PCI window
  60  *  return: size of actual ROM image
  61  *
  62  * Determine the actual length of the ROM image.
  63  * The PCI window size could be much larger than the
  64  * actual image size.
  65  */
  66 size_t pci_get_rom_size(void __iomem *rom, size_t size)
  67 {
  68         void __iomem *image;
  69         int last_image;
  70
  71         image = rom;
  72         do {
  73                 void __iomem *pds;
  74                 /* Standard PCI ROMs start out with these bytes 55 AA */
  75                 if (readb(image) != 0x55)
  76                         break;
  77                 if (readb(image + 1) != 0xAA)
  78                         break;
  79                 /* get the PCI data structure and check its signature */
  80                 pds = image + readw(image + 24);
  81                 if (readb(pds) != 'P')
  82                         break;
  83                 if (readb(pds + 1) != 'C')
  84                         break;
  85                 if (readb(pds + 2) != 'I')
  86                         break;
  87                 if (readb(pds + 3) != 'R')
  88                         break;
  89                 last_image = readb(pds + 21) & 0x80;
  90                 /* this length is reliable */
  91                 image += readw(pds + 16) * 512;
  92         } while (!last_image);
  93
  94         /* never return a size larger than the PCI resource window */
  95         /* there are known ROMs that get the size wrong */
  96         return min((size_t)(image - rom), size);
  97 }
  98
  99 /**
 100  * pci_map_rom - map a PCI ROM to kernel space
 101  * @pdev: pointer to pci device struct
 102  * @size: pointer to receive size of pci window over ROM
 103  * @return: kernel virtual pointer to image of ROM
 104  *
 105  * Map a PCI ROM into kernel space. If ROM is boot video ROM,
 106  * the shadow BIOS copy will be returned instead of the
 107  * actual ROM.
 108  */
 109 void __iomem *pci_map_rom(struct pci_dev *pdev, size_t *size)
 110 {
 111         struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
 112         loff_t start;
 113         void __iomem *rom;
 114
 115         /*
 116          * IORESOURCE_ROM_SHADOW set on x86, x86_64 and IA64 supports legacy
 117          * memory map if the VGA enable bit of the Bridge Control register is
 118          * set for embedded VGA.
 119          */
 120         if (res->flags & IORESOURCE_ROM_SHADOW) {
 121                 /* primary video rom always starts here */
 122                 start = (loff_t)0xC0000;
 123                 *size = 0x20000; /* cover C000:0 through E000:0 */
 124         } else {
 125                 if (res->flags &
 126                         (IORESOURCE_ROM_COPY | IORESOURCE_ROM_BIOS_COPY)) {
 127                         *size = pci_resource_len(pdev, PCI_ROM_RESOURCE);
 128                         return (void __iomem *)(unsigned long)
 129                                 pci_resource_start(pdev, PCI_ROM_RESOURCE);
 130                 } else {
 131                         /* assign the ROM an address if it doesn't have one */
 132                         if (res->parent == NULL &&
 133                             pci_assign_resource(pdev,PCI_ROM_RESOURCE))
 134                                 return NULL;
 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         }
 145
 146         rom = ioremap(start, *size);
 147         if (!rom) {
 148                 /* restore enable if ioremap fails */
 149                 if (!(res->flags & (IORESOURCE_ROM_ENABLE |
 150                                     IORESOURCE_ROM_SHADOW |
 151                                     IORESOURCE_ROM_COPY)))
 152                         pci_disable_rom(pdev);
 153                 return NULL;
 154         }
 155
 156         /*
 157          * Try to find the true size of the ROM since sometimes the PCI window
 158          * size is much larger than the actual size of the ROM.
 159          * True size is important if the ROM is going to be copied.
 160          */
 161         *size = pci_get_rom_size(rom, *size);
 162         return rom;
 163 }
 164
 165 #if 0
 166 /**
 167  * pci_map_rom_copy - map a PCI ROM to kernel space, create a copy
 168  * @pdev: pointer to pci device struct
 169  * @size: pointer to receive size of pci window over ROM
 170  * @return: kernel virtual pointer to image of ROM
 171  *
 172  * Map a PCI ROM into kernel space. If ROM is boot video ROM,
 173  * the shadow BIOS copy will be returned instead of the
 174  * actual ROM.
 175  */
 176 void __iomem *pci_map_rom_copy(struct pci_dev *pdev, size_t *size)
 177 {
 178         struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
 179         void __iomem *rom;
 180
 181         rom = pci_map_rom(pdev, size);
 182         if (!rom)
 183                 return NULL;
 184
 185         if (res->flags & (IORESOURCE_ROM_COPY | IORESOURCE_ROM_SHADOW |
 186                           IORESOURCE_ROM_BIOS_COPY))
 187                 return rom;
 188
 189         res->start = (unsigned long)kmalloc(*size, GFP_KERNEL);
 190         if (!res->start)
 191                 return rom;
 192
 193         res->end = res->start + *size;
 194         memcpy_fromio((void*)(unsigned long)res->start, rom, *size);
 195         pci_unmap_rom(pdev, rom);
 196         res->flags |= IORESOURCE_ROM_COPY;
 197
 198         return (void __iomem *)(unsigned long)res->start;
 199 }
 200 #endif  /*  0  */
 201
 202 /**
 203  * pci_unmap_rom - unmap the ROM from kernel space
 204  * @pdev: pointer to pci device struct
 205  * @rom: virtual address of the previous mapping
 206  *
 207  * Remove a mapping of a previously mapped ROM
 208  */
 209 void pci_unmap_rom(struct pci_dev *pdev, void __iomem *rom)
 210 {
 211         struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
 212
 213         if (res->flags & (IORESOURCE_ROM_COPY | IORESOURCE_ROM_BIOS_COPY))
 214                 return;
 215
 216         iounmap(rom);
 217
 218         /* Disable again before continuing, leave enabled if pci=rom */
 219         if (!(res->flags & (IORESOURCE_ROM_ENABLE | IORESOURCE_ROM_SHADOW)))
 220                 pci_disable_rom(pdev);
 221 }
 222
 223 #if 0
 224 /**
 225  * pci_remove_rom - disable the ROM and remove its sysfs attribute
 226  * @pdev: pointer to pci device struct
 227  *
 228  * Remove the rom file in sysfs and disable ROM decoding.
 229  */
 230 void pci_remove_rom(struct pci_dev *pdev)
 231 {
 232         struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
 233
 234         if (pci_resource_len(pdev, PCI_ROM_RESOURCE))
 235                 sysfs_remove_bin_file(&pdev->dev.kobj, pdev->rom_attr);
 236         if (!(res->flags & (IORESOURCE_ROM_ENABLE |
 237                             IORESOURCE_ROM_SHADOW |
 238                             IORESOURCE_ROM_BIOS_COPY |
 239                             IORESOURCE_ROM_COPY)))
 240                 pci_disable_rom(pdev);
 241 }
 242 #endif  /*  0  */
 243
 244 /**
 245  * pci_cleanup_rom - free the ROM copy created by pci_map_rom_copy
 246  * @pdev: pointer to pci device struct
 247  *
 248  * Free the copied ROM if we allocated one.
 249  */
 250 void pci_cleanup_rom(struct pci_dev *pdev)
 251 {
 252         struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
 253         if (res->flags & IORESOURCE_ROM_COPY) {
 254                 kfree((void*)(unsigned long)res->start);
 255                 res->flags &= ~IORESOURCE_ROM_COPY;
 256                 res->start = 0;
 257                 res->end = 0;
 258         }
 259 }
 260
 261 EXPORT_SYMBOL(pci_map_rom);
 262 EXPORT_SYMBOL(pci_unmap_rom);