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