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