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
  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 void pci_enable_rom(struct pci_dev *pdev)
  25 {
  26         u32 rom_addr;
  27
  28         pci_read_config_dword(pdev, pdev->rom_base_reg, &rom_addr);
  29         rom_addr |= PCI_ROM_ADDRESS_ENABLE;
  30         pci_write_config_dword(pdev, pdev->rom_base_reg, rom_addr);
  31 }
  32
  33 /**
  34  * pci_disable_rom - disable ROM decoding for a PCI device
  35  * @pdev: PCI device to disable
  36  *
  37  * Disable ROM decoding on a PCI device by turning off the last bit in the
  38  * ROM BAR.
  39  */
  40 static void pci_disable_rom(struct pci_dev *pdev)
  41 {
  42         u32 rom_addr;
  43         pci_read_config_dword(pdev, pdev->rom_base_reg, &rom_addr);
  44         rom_addr &= ~PCI_ROM_ADDRESS_ENABLE;
  45         pci_write_config_dword(pdev, pdev->rom_base_reg, rom_addr);
  46 }
  47
  48 /**
  49  * pci_map_rom - map a PCI ROM to kernel space
  50  * @pdev: pointer to pci device struct
  51  * @size: pointer to receive size of pci window over ROM
  52  * @return: kernel virtual pointer to image of ROM
  53  *
  54  * Map a PCI ROM into kernel space. If ROM is boot video ROM,
  55  * the shadow BIOS copy will be returned instead of the
  56  * actual ROM.
  57  */
  58 void __iomem *pci_map_rom(struct pci_dev *pdev, size_t *size)
  59 {
  60         struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
  61         loff_t start;
  62         void __iomem *rom;
  63         void __iomem *image;
  64         int last_image;
  65
  66         /* IORESOURCE_ROM_SHADOW only set on x86 */
  67         if (res->flags & IORESOURCE_ROM_SHADOW) {
  68                 /* primary video rom always starts here */
  69                 start = (loff_t)0xC0000;
  70                 *size = 0x20000; /* cover C000:0 through E000:0 */
  71         } else {
  72                 if (res->flags & IORESOURCE_ROM_COPY) {
  73                         *size = pci_resource_len(pdev, PCI_ROM_RESOURCE);
  74                         return (void __iomem *)pci_resource_start(pdev, PCI_ROM_RESOURCE);
  75                 } else {
  76                         /* assign the ROM an address if it doesn't have one */
  77                         if (res->parent == NULL)
  78                                 pci_assign_resource(pdev, PCI_ROM_RESOURCE);
  79
  80                         start = pci_resource_start(pdev, PCI_ROM_RESOURCE);
  81                         *size = pci_resource_len(pdev, PCI_ROM_RESOURCE);
  82                         if (*size == 0)
  83                                 return NULL;
  84
  85                         /* Enable ROM space decodes */
  86                         pci_enable_rom(pdev);
  87                 }
  88         }
  89
  90         rom = ioremap(start, *size);
  91         if (!rom) {
  92                 /* restore enable if ioremap fails */
  93                 if (!(res->flags & (IORESOURCE_ROM_ENABLE |
  94                                     IORESOURCE_ROM_SHADOW |
  95                                     IORESOURCE_ROM_COPY)))
  96                         pci_disable_rom(pdev);
  97                 return NULL;
  98         }
  99
 100         /*
 101          * Try to find the true size of the ROM since sometimes the PCI window
 102          * size is much larger than the actual size of the ROM.
 103          * True size is important if the ROM is going to be copied.
 104          */
 105         image = rom;
 106         do {
 107                 void __iomem *pds;
 108                 /* Standard PCI ROMs start out with these bytes 55 AA */
 109                 if (readb(image) != 0x55)
 110                         break;
 111                 if (readb(image + 1) != 0xAA)
 112                         break;
 113                 /* get the PCI data structure and check its signature */
 114                 pds = image + readw(image + 24);
 115                 if (readb(pds) != 'P')
 116                         break;
 117                 if (readb(pds + 1) != 'C')
 118                         break;
 119                 if (readb(pds + 2) != 'I')
 120                         break;
 121                 if (readb(pds + 3) != 'R')
 122                         break;
 123                 last_image = readb(pds + 21) & 0x80;
 124                 /* this length is reliable */
 125                 image += readw(pds + 16) * 512;
 126         } while (!last_image);
 127
 128         /* never return a size larger than the PCI resource window */
 129         /* there are known ROMs that get the size wrong */
 130         *size = min((size_t)(image - rom), *size);
 131
 132         return rom;
 133 }
 134
 135 /**
 136  * pci_map_rom_copy - map a PCI ROM to kernel space, create a copy
 137  * @pdev: pointer to pci device struct
 138  * @size: pointer to receive size of pci window over ROM
 139  * @return: kernel virtual pointer to image of ROM
 140  *
 141  * Map a PCI ROM into kernel space. If ROM is boot video ROM,
 142  * the shadow BIOS copy will be returned instead of the
 143  * actual ROM.
 144  */
 145 void __iomem *pci_map_rom_copy(struct pci_dev *pdev, size_t *size)
 146 {
 147         struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
 148         void __iomem *rom;
 149
 150         rom = pci_map_rom(pdev, size);
 151         if (!rom)
 152                 return NULL;
 153
 154         if (res->flags & (IORESOURCE_ROM_COPY | IORESOURCE_ROM_SHADOW))
 155                 return rom;
 156
 157         res->start = (unsigned long)kmalloc(*size, GFP_KERNEL);
 158         if (!res->start)
 159                 return rom;
 160
 161         res->end = res->start + *size;
 162         memcpy_fromio((void*)res->start, rom, *size);
 163         pci_unmap_rom(pdev, rom);
 164         res->flags |= IORESOURCE_ROM_COPY;
 165
 166         return (void __iomem *)res->start;
 167 }
 168
 169 /**
 170  * pci_unmap_rom - unmap the ROM from kernel space
 171  * @pdev: pointer to pci device struct
 172  * @rom: virtual address of the previous mapping
 173  *
 174  * Remove a mapping of a previously mapped ROM
 175  */
 176 void pci_unmap_rom(struct pci_dev *pdev, void __iomem *rom)
 177 {
 178         struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
 179
 180         if (res->flags & IORESOURCE_ROM_COPY)
 181                 return;
 182
 183         iounmap(rom);
 184
 185         /* Disable again before continuing, leave enabled if pci=rom */
 186         if (!(res->flags & (IORESOURCE_ROM_ENABLE | IORESOURCE_ROM_SHADOW)))
 187                 pci_disable_rom(pdev);
 188 }
 189
 190 /**
 191  * pci_remove_rom - disable the ROM and remove its sysfs attribute
 192  * @pdev: pointer to pci device struct
 193  *
 194  * Remove the rom file in sysfs and disable ROM decoding.
 195  */
 196 void pci_remove_rom(struct pci_dev *pdev)
 197 {
 198         struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
 199
 200         if (pci_resource_len(pdev, PCI_ROM_RESOURCE))
 201                 sysfs_remove_bin_file(&pdev->dev.kobj, pdev->rom_attr);
 202         if (!(res->flags & (IORESOURCE_ROM_ENABLE |
 203                             IORESOURCE_ROM_SHADOW |
 204                             IORESOURCE_ROM_COPY)))
 205                 pci_disable_rom(pdev);
 206 }
 207
 208 /**
 209  * pci_cleanup_rom - internal routine for freeing the ROM copy created
 210  * by pci_map_rom_copy called from remove.c
 211  * @pdev: pointer to pci device struct
 212  *
 213  * Free the copied ROM if we allocated one.
 214  */
 215 void pci_cleanup_rom(struct pci_dev *pdev)
 216 {
 217         struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
 218         if (res->flags & IORESOURCE_ROM_COPY) {
 219                 kfree((void*)res->start);
 220                 res->flags &= ~IORESOURCE_ROM_COPY;
 221                 res->start = 0;
 222                 res->end = 0;
 223         }
 224 }
 225
 226 EXPORT_SYMBOL(pci_map_rom);
 227 EXPORT_SYMBOL(pci_map_rom_copy);
 228 EXPORT_SYMBOL(pci_unmap_rom);
 229 EXPORT_SYMBOL(pci_remove_rom);