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/config.h>
  10 #include <linux/kernel.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 static 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, &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
  42 /**
  43  * pci_disable_rom - disable ROM decoding for a PCI device
  44  * @pdev: PCI device to disable
  45  *
  46  * Disable ROM decoding on a PCI device by turning off the last bit in the
  47  * ROM BAR.
  48  */
  49 static void pci_disable_rom(struct pci_dev *pdev)
  50 {
  51         u32 rom_addr;
  52         pci_read_config_dword(pdev, pdev->rom_base_reg, &rom_addr);
  53         rom_addr &= ~PCI_ROM_ADDRESS_ENABLE;
  54         pci_write_config_dword(pdev, pdev->rom_base_reg, rom_addr);
  55 }
  56
  57 /**
  58  * pci_map_rom - map a PCI ROM to kernel space
  59  * @pdev: pointer to pci device struct
  60  * @size: pointer to receive size of pci window over ROM
  61  * @return: kernel virtual pointer to image of ROM
  62  *
  63  * Map a PCI ROM into kernel space. If ROM is boot video ROM,
  64  * the shadow BIOS copy will be returned instead of the
  65  * actual ROM.
  66  */
  67 void __iomem *pci_map_rom(struct pci_dev *pdev, size_t *size)
  68 {
  69         struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
  70         loff_t start;
  71         void __iomem *rom;
  72         void __iomem *image;
  73         int last_image;
  74
  75         /* IORESOURCE_ROM_SHADOW only set on x86 */
  76         if (res->flags & IORESOURCE_ROM_SHADOW) {
  77                 /* primary video rom always starts here */
  78                 start = (loff_t)0xC0000;
  79                 *size = 0x20000; /* cover C000:0 through E000:0 */
  80         } else {
  81                 if (res->flags & IORESOURCE_ROM_COPY) {
  82                         *size = pci_resource_len(pdev, PCI_ROM_RESOURCE);
  83                         return (void __iomem *)pci_resource_start(pdev,
  84                                                              PCI_ROM_RESOURCE);
  85                 } else {
  86                         /* assign the ROM an address if it doesn't have one */
  87                         if (res->parent == NULL &&
  88                             pci_assign_resource(pdev,PCI_ROM_RESOURCE))
  89                                 return NULL;
  90                         start = pci_resource_start(pdev, PCI_ROM_RESOURCE);
  91                         *size = pci_resource_len(pdev, PCI_ROM_RESOURCE);
  92                         if (*size == 0)
  93                                 return NULL;
  94
  95                         /* Enable ROM space decodes */
  96                         if (pci_enable_rom(pdev))
  97                                 return NULL;
  98                 }
  99         }
 100
 101         rom = ioremap(start, *size);
 102         if (!rom) {
 103                 /* restore enable if ioremap fails */
 104                 if (!(res->flags & (IORESOURCE_ROM_ENABLE |
 105                                     IORESOURCE_ROM_SHADOW |
 106                                     IORESOURCE_ROM_COPY)))
 107                         pci_disable_rom(pdev);
 108                 return NULL;
 109         }
 110
 111         /*
 112          * Try to find the true size of the ROM since sometimes the PCI window
 113          * size is much larger than the actual size of the ROM.
 114          * True size is important if the ROM is going to be copied.
 115          */
 116         image = rom;
 117         do {
 118                 void __iomem *pds;
 119                 /* Standard PCI ROMs start out with these bytes 55 AA */
 120                 if (readb(image) != 0x55)
 121                         break;
 122                 if (readb(image + 1) != 0xAA)
 123                         break;
 124                 /* get the PCI data structure and check its signature */
 125                 pds = image + readw(image + 24);
 126                 if (readb(pds) != 'P')
 127                         break;
 128                 if (readb(pds + 1) != 'C')
 129                         break;
 130                 if (readb(pds + 2) != 'I')
 131                         break;
 132                 if (readb(pds + 3) != 'R')
 133                         break;
 134                 last_image = readb(pds + 21) & 0x80;
 135                 /* this length is reliable */
 136                 image += readw(pds + 16) * 512;
 137         } while (!last_image);
 138
 139         /* never return a size larger than the PCI resource window */
 140         /* there are known ROMs that get the size wrong */
 141         *size = min((size_t)(image - rom), *size);
 142
 143         return rom;
 144 }
 145
 146 /**
 147  * pci_map_rom_copy - map a PCI ROM to kernel space, create a copy
 148  * @pdev: pointer to pci device struct
 149  * @size: pointer to receive size of pci window over ROM
 150  * @return: kernel virtual pointer to image of ROM
 151  *
 152  * Map a PCI ROM into kernel space. If ROM is boot video ROM,
 153  * the shadow BIOS copy will be returned instead of the
 154  * actual ROM.
 155  */
 156 void __iomem *pci_map_rom_copy(struct pci_dev *pdev, size_t *size)
 157 {
 158         struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
 159         void __iomem *rom;
 160
 161         rom = pci_map_rom(pdev, size);
 162         if (!rom)
 163                 return NULL;
 164
 165         if (res->flags & (IORESOURCE_ROM_COPY | IORESOURCE_ROM_SHADOW))
 166                 return rom;
 167
 168         res->start = (unsigned long)kmalloc(*size, GFP_KERNEL);
 169         if (!res->start)
 170                 return rom;
 171
 172         res->end = res->start + *size;
 173         memcpy_fromio((void*)res->start, rom, *size);
 174         pci_unmap_rom(pdev, rom);
 175         res->flags |= IORESOURCE_ROM_COPY;
 176
 177         return (void __iomem *)res->start;
 178 }
 179
 180 /**
 181  * pci_unmap_rom - unmap the ROM from kernel space
 182  * @pdev: pointer to pci device struct
 183  * @rom: virtual address of the previous mapping
 184  *
 185  * Remove a mapping of a previously mapped ROM
 186  */
 187 void pci_unmap_rom(struct pci_dev *pdev, void __iomem *rom)
 188 {
 189         struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
 190
 191         if (res->flags & IORESOURCE_ROM_COPY)
 192                 return;
 193
 194         iounmap(rom);
 195
 196         /* Disable again before continuing, leave enabled if pci=rom */
 197         if (!(res->flags & (IORESOURCE_ROM_ENABLE | IORESOURCE_ROM_SHADOW)))
 198                 pci_disable_rom(pdev);
 199 }
 200
 201 /**
 202  * pci_remove_rom - disable the ROM and remove its sysfs attribute
 203  * @pdev: pointer to pci device struct
 204  *
 205  * Remove the rom file in sysfs and disable ROM decoding.
 206  */
 207 void pci_remove_rom(struct pci_dev *pdev)
 208 {
 209         struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
 210
 211         if (pci_resource_len(pdev, PCI_ROM_RESOURCE))
 212                 sysfs_remove_bin_file(&pdev->dev.kobj, pdev->rom_attr);
 213         if (!(res->flags & (IORESOURCE_ROM_ENABLE |
 214                             IORESOURCE_ROM_SHADOW |
 215                             IORESOURCE_ROM_COPY)))
 216                 pci_disable_rom(pdev);
 217 }
 218
 219 /**
 220  * pci_cleanup_rom - internal routine for freeing the ROM copy created
 221  * by pci_map_rom_copy called from remove.c
 222  * @pdev: pointer to pci device struct
 223  *
 224  * Free the copied ROM if we allocated one.
 225  */
 226 void pci_cleanup_rom(struct pci_dev *pdev)
 227 {
 228         struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
 229         if (res->flags & IORESOURCE_ROM_COPY) {
 230                 kfree((void*)res->start);
 231                 res->flags &= ~IORESOURCE_ROM_COPY;
 232                 res->start = 0;
 233                 res->end = 0;
 234         }
 235 }
 236
 237 EXPORT_SYMBOL(pci_map_rom);
 238 EXPORT_SYMBOL(pci_map_rom_copy);
 239 EXPORT_SYMBOL(pci_unmap_rom);
 240 EXPORT_SYMBOL(pci_remove_rom);