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_map_rom - map a PCI ROM to kernel space
  58  * @pdev: pointer to pci device struct
  59  * @size: pointer to receive size of pci window over ROM
  60  * @return: kernel virtual pointer to image of ROM
  61  *
  62  * Map a PCI ROM into kernel space. If ROM is boot video ROM,
  63  * the shadow BIOS copy will be returned instead of the
  64  * actual ROM.
  65  */
  66 void __iomem *pci_map_rom(struct pci_dev *pdev, size_t *size)
  67 {
  68         struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
  69         loff_t start;
  70         void __iomem *rom;
  71         void __iomem *image;
  72         int last_image;
  73
  74         /*
  75          * IORESOURCE_ROM_SHADOW set on x86, x86_64 and IA64 supports legacy
  76          * memory map if the VGA enable bit of the Bridge Control register is
  77          * set for embedded VGA.
  78          */
  79         if (res->flags & IORESOURCE_ROM_SHADOW) {
  80                 /* primary video rom always starts here */
  81                 start = (loff_t)0xC0000;
  82                 *size = 0x20000; /* cover C000:0 through E000:0 */
  83         } else {
  84                 if (res->flags & IORESOURCE_ROM_COPY) {
  85                         *size = pci_resource_len(pdev, PCI_ROM_RESOURCE);
  86                         return (void __iomem *)(unsigned long)
  87                                 pci_resource_start(pdev, PCI_ROM_RESOURCE);
  88                 } else {
  89                         /* assign the ROM an address if it doesn't have one */
  90                         if (res->parent == NULL &&
  91                             pci_assign_resource(pdev,PCI_ROM_RESOURCE))
  92                                 return NULL;
  93                         start = pci_resource_start(pdev, PCI_ROM_RESOURCE);
  94                         *size = pci_resource_len(pdev, PCI_ROM_RESOURCE);
  95                         if (*size == 0)
  96                                 return NULL;
  97
  98                         /* Enable ROM space decodes */
  99                         if (pci_enable_rom(pdev))
 100                                 return NULL;
 101                 }
 102         }
 103
 104         rom = ioremap(start, *size);
 105         if (!rom) {
 106                 /* restore enable if ioremap fails */
 107                 if (!(res->flags & (IORESOURCE_ROM_ENABLE |
 108                                     IORESOURCE_ROM_SHADOW |
 109                                     IORESOURCE_ROM_COPY)))
 110                         pci_disable_rom(pdev);
 111                 return NULL;
 112         }
 113
 114         /*
 115          * Try to find the true size of the ROM since sometimes the PCI window
 116          * size is much larger than the actual size of the ROM.
 117          * True size is important if the ROM is going to be copied.
 118          */
 119         image = rom;
 120         do {
 121                 void __iomem *pds;
 122                 /* Standard PCI ROMs start out with these bytes 55 AA */
 123                 if (readb(image) != 0x55)
 124                         break;
 125                 if (readb(image + 1) != 0xAA)
 126                         break;
 127                 /* get the PCI data structure and check its signature */
 128                 pds = image + readw(image + 24);
 129                 if (readb(pds) != 'P')
 130                         break;
 131                 if (readb(pds + 1) != 'C')
 132                         break;
 133                 if (readb(pds + 2) != 'I')
 134                         break;
 135                 if (readb(pds + 3) != 'R')
 136                         break;
 137                 last_image = readb(pds + 21) & 0x80;
 138                 /* this length is reliable */
 139                 image += readw(pds + 16) * 512;
 140         } while (!last_image);
 141
 142         /* never return a size larger than the PCI resource window */
 143         /* there are known ROMs that get the size wrong */
 144         *size = min((size_t)(image - rom), *size);
 145
 146         return rom;
 147 }
 148
 149 /**
 150  * pci_map_rom_copy - map a PCI ROM to kernel space, create a copy
 151  * @pdev: pointer to pci device struct
 152  * @size: pointer to receive size of pci window over ROM
 153  * @return: kernel virtual pointer to image of ROM
 154  *
 155  * Map a PCI ROM into kernel space. If ROM is boot video ROM,
 156  * the shadow BIOS copy will be returned instead of the
 157  * actual ROM.
 158  */
 159 void __iomem *pci_map_rom_copy(struct pci_dev *pdev, size_t *size)
 160 {
 161         struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
 162         void __iomem *rom;
 163
 164         rom = pci_map_rom(pdev, size);
 165         if (!rom)
 166                 return NULL;
 167
 168         if (res->flags & (IORESOURCE_ROM_COPY | IORESOURCE_ROM_SHADOW))
 169                 return rom;
 170
 171         res->start = (unsigned long)kmalloc(*size, GFP_KERNEL);
 172         if (!res->start)
 173                 return rom;
 174
 175         res->end = res->start + *size;
 176         memcpy_fromio((void*)(unsigned long)res->start, rom, *size);
 177         pci_unmap_rom(pdev, rom);
 178         res->flags |= IORESOURCE_ROM_COPY;
 179
 180         return (void __iomem *)(unsigned long)res->start;
 181 }
 182
 183 /**
 184  * pci_unmap_rom - unmap the ROM from kernel space
 185  * @pdev: pointer to pci device struct
 186  * @rom: virtual address of the previous mapping
 187  *
 188  * Remove a mapping of a previously mapped ROM
 189  */
 190 void pci_unmap_rom(struct pci_dev *pdev, void __iomem *rom)
 191 {
 192         struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
 193
 194         if (res->flags & IORESOURCE_ROM_COPY)
 195                 return;
 196
 197         iounmap(rom);
 198
 199         /* Disable again before continuing, leave enabled if pci=rom */
 200         if (!(res->flags & (IORESOURCE_ROM_ENABLE | IORESOURCE_ROM_SHADOW)))
 201                 pci_disable_rom(pdev);
 202 }
 203
 204 /**
 205  * pci_remove_rom - disable the ROM and remove its sysfs attribute
 206  * @pdev: pointer to pci device struct
 207  *
 208  * Remove the rom file in sysfs and disable ROM decoding.
 209  */
 210 void pci_remove_rom(struct pci_dev *pdev)
 211 {
 212         struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
 213
 214         if (pci_resource_len(pdev, PCI_ROM_RESOURCE))
 215                 sysfs_remove_bin_file(&pdev->dev.kobj, pdev->rom_attr);
 216         if (!(res->flags & (IORESOURCE_ROM_ENABLE |
 217                             IORESOURCE_ROM_SHADOW |
 218                             IORESOURCE_ROM_COPY)))
 219                 pci_disable_rom(pdev);
 220 }
 221
 222 /**
 223  * pci_cleanup_rom - internal routine for freeing the ROM copy created
 224  * by pci_map_rom_copy called from remove.c
 225  * @pdev: pointer to pci device struct
 226  *
 227  * Free the copied ROM if we allocated one.
 228  */
 229 void pci_cleanup_rom(struct pci_dev *pdev)
 230 {
 231         struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
 232         if (res->flags & IORESOURCE_ROM_COPY) {
 233                 kfree((void*)(unsigned long)res->start);
 234                 res->flags &= ~IORESOURCE_ROM_COPY;
 235                 res->start = 0;
 236                 res->end = 0;
 237         }
 238 }
 239
 240 EXPORT_SYMBOL(pci_map_rom);
 241 EXPORT_SYMBOL(pci_map_rom_copy);
 242 EXPORT_SYMBOL(pci_unmap_rom);
 243 EXPORT_SYMBOL(pci_remove_rom);