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 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 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(struct pci_dev *pdev, 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                         dev_err(&pdev->dev, "Invalid ROM contents\n");
  77                         break;
  78                 }
  79                 if (readb(image + 1) != 0xAA)
  80                         break;
  81                 /* get the PCI data structure and check its signature */
  82                 pds = image + readw(image + 24);
  83                 if (readb(pds) != 'P')
  84                         break;
  85                 if (readb(pds + 1) != 'C')
  86                         break;
  87                 if (readb(pds + 2) != 'I')
  88                         break;
  89                 if (readb(pds + 3) != 'R')
  90                         break;
  91                 last_image = readb(pds + 21) & 0x80;
  92                 /* this length is reliable */
  93                 image += readw(pds + 16) * 512;
  94         } while (!last_image);
  95
  96         /* never return a size larger than the PCI resource window */
  97         /* there are known ROMs that get the size wrong */
  98         return min((size_t)(image - rom), size);
  99 }
 100
 101 /**
 102  * pci_map_rom - map a PCI ROM to kernel space
 103  * @pdev: pointer to pci device struct
 104  * @size: pointer to receive size of pci window over ROM
 105  *
 106  * Return: kernel virtual pointer to image of ROM
 107  *
 108  * Map a PCI ROM into kernel space. If ROM is boot video ROM,
 109  * the shadow BIOS copy will be returned instead of the
 110  * actual ROM.
 111  */
 112 void __iomem *pci_map_rom(struct pci_dev *pdev, size_t *size)
 113 {
 114         struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
 115         loff_t start;
 116         void __iomem *rom;
 117
 118         /*
 119          * IORESOURCE_ROM_SHADOW set on x86, x86_64 and IA64 supports legacy
 120          * memory map if the VGA enable bit of the Bridge Control register is
 121          * set for embedded VGA.
 122          */
 123         if (res->flags & IORESOURCE_ROM_SHADOW) {
 124                 /* primary video rom always starts here */
 125                 start = (loff_t)0xC0000;
 126                 *size = 0x20000; /* cover C000:0 through E000:0 */
 127         } else {
 128                 if (res->flags &
 129                         (IORESOURCE_ROM_COPY | IORESOURCE_ROM_BIOS_COPY)) {
 130                         *size = pci_resource_len(pdev, PCI_ROM_RESOURCE);
 131                         return (void __iomem *)(unsigned long)
 132                                 pci_resource_start(pdev, PCI_ROM_RESOURCE);
 133                 } else {
 134                         /* assign the ROM an address if it doesn't have one */
 135                         if (res->parent == NULL &&
 136                             pci_assign_resource(pdev,PCI_ROM_RESOURCE))
 137                                 return NULL;
 138                         start = pci_resource_start(pdev, PCI_ROM_RESOURCE);
 139                         *size = pci_resource_len(pdev, PCI_ROM_RESOURCE);
 140                         if (*size == 0)
 141                                 return NULL;
 142
 143                         /* Enable ROM space decodes */
 144                         if (pci_enable_rom(pdev))
 145                                 return NULL;
 146                 }
 147         }
 148
 149         rom = ioremap(start, *size);
 150         if (!rom) {
 151                 /* restore enable if ioremap fails */
 152                 if (!(res->flags & (IORESOURCE_ROM_ENABLE |
 153                                     IORESOURCE_ROM_SHADOW |
 154                                     IORESOURCE_ROM_COPY)))
 155                         pci_disable_rom(pdev);
 156                 return NULL;
 157         }
 158
 159         /*
 160          * Try to find the true size of the ROM since sometimes the PCI window
 161          * size is much larger than the actual size of the ROM.
 162          * True size is important if the ROM is going to be copied.
 163          */
 164         *size = pci_get_rom_size(pdev, rom, *size);
 165         return rom;
 166 }
 167
 168 #if 0
 169 /**
 170  * pci_map_rom_copy - map a PCI ROM to kernel space, create a copy
 171  * @pdev: pointer to pci device struct
 172  * @size: pointer to receive size of pci window over ROM
 173  *
 174  * Return: kernel virtual pointer to image of ROM
 175  *
 176  * Map a PCI ROM into kernel space. If ROM is boot video ROM,
 177  * the shadow BIOS copy will be returned instead of the
 178  * actual ROM.
 179  */
 180 void __iomem *pci_map_rom_copy(struct pci_dev *pdev, size_t *size)
 181 {
 182         struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
 183         void __iomem *rom;
 184
 185         rom = pci_map_rom(pdev, size);
 186         if (!rom)
 187                 return NULL;
 188
 189         if (res->flags & (IORESOURCE_ROM_COPY | IORESOURCE_ROM_SHADOW |
 190                           IORESOURCE_ROM_BIOS_COPY))
 191                 return rom;
 192
 193         res->start = (unsigned long)kmalloc(*size, GFP_KERNEL);
 194         if (!res->start)
 195                 return rom;
 196
 197         res->end = res->start + *size;
 198         memcpy_fromio((void*)(unsigned long)res->start, rom, *size);
 199         pci_unmap_rom(pdev, rom);
 200         res->flags |= IORESOURCE_ROM_COPY;
 201
 202         return (void __iomem *)(unsigned long)res->start;
 203 }
 204 #endif  /*  0  */
 205
 206 /**
 207  * pci_unmap_rom - unmap the ROM from kernel space
 208  * @pdev: pointer to pci device struct
 209  * @rom: virtual address of the previous mapping
 210  *
 211  * Remove a mapping of a previously mapped ROM
 212  */
 213 void pci_unmap_rom(struct pci_dev *pdev, void __iomem *rom)
 214 {
 215         struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
 216
 217         if (res->flags & (IORESOURCE_ROM_COPY | IORESOURCE_ROM_BIOS_COPY))
 218                 return;
 219
 220         iounmap(rom);
 221
 222         /* Disable again before continuing, leave enabled if pci=rom */
 223         if (!(res->flags & (IORESOURCE_ROM_ENABLE | IORESOURCE_ROM_SHADOW)))
 224                 pci_disable_rom(pdev);
 225 }
 226
 227 #if 0
 228 /**
 229  * pci_remove_rom - disable the ROM and remove its sysfs attribute
 230  * @pdev: pointer to pci device struct
 231  *
 232  * Remove the rom file in sysfs and disable ROM decoding.
 233  */
 234 void pci_remove_rom(struct pci_dev *pdev)
 235 {
 236         struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
 237
 238         if (pci_resource_len(pdev, PCI_ROM_RESOURCE))
 239                 sysfs_remove_bin_file(&pdev->dev.kobj, pdev->rom_attr);
 240         if (!(res->flags & (IORESOURCE_ROM_ENABLE |
 241                             IORESOURCE_ROM_SHADOW |
 242                             IORESOURCE_ROM_BIOS_COPY |
 243                             IORESOURCE_ROM_COPY)))
 244                 pci_disable_rom(pdev);
 245 }
 246 #endif  /*  0  */
 247
 248 /**
 249  * pci_cleanup_rom - free the ROM copy created by pci_map_rom_copy
 250  * @pdev: pointer to pci device struct
 251  *
 252  * Free the copied ROM if we allocated one.
 253  */
 254 void pci_cleanup_rom(struct pci_dev *pdev)
 255 {
 256         struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
 257         if (res->flags & IORESOURCE_ROM_COPY) {
 258                 kfree((void*)(unsigned long)res->start);
 259                 res->flags &= ~IORESOURCE_ROM_COPY;
 260                 res->start = 0;
 261                 res->end = 0;
 262         }
 263 }
 264
 265 EXPORT_SYMBOL(pci_map_rom);
 266 EXPORT_SYMBOL(pci_unmap_rom);
 267 EXPORT_SYMBOL_GPL(pci_enable_rom);
 268 EXPORT_SYMBOL_GPL(pci_disable_rom);