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