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->bus, ®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 EXPORT_SYMBOL_GPL(pci_enable_rom); 42 43 /** 44 * pci_disable_rom - disable ROM decoding for a PCI device 45 * @pdev: PCI device to disable 46 * 47 * Disable ROM decoding on a PCI device by turning off the last bit in the 48 * ROM BAR. 49 */ 50 void pci_disable_rom(struct pci_dev *pdev) 51 { 52 u32 rom_addr; 53 pci_read_config_dword(pdev, pdev->rom_base_reg, &rom_addr); 54 rom_addr &= ~PCI_ROM_ADDRESS_ENABLE; 55 pci_write_config_dword(pdev, pdev->rom_base_reg, rom_addr); 56 } 57 EXPORT_SYMBOL_GPL(pci_disable_rom); 58 59 /** 60 * pci_get_rom_size - obtain the actual size of the ROM image 61 * @pdev: target PCI device 62 * @rom: kernel virtual pointer to image of ROM 63 * @size: size of PCI window 64 * return: size of actual ROM image 65 * 66 * Determine the actual length of the ROM image. 67 * The PCI window size could be much larger than the 68 * actual image size. 69 */ 70 size_t pci_get_rom_size(struct pci_dev *pdev, void __iomem *rom, size_t size) 71 { 72 void __iomem *image; 73 int last_image; 74 unsigned length; 75 76 image = rom; 77 do { 78 void __iomem *pds; 79 /* Standard PCI ROMs start out with these bytes 55 AA */ 80 if (readb(image) != 0x55) { 81 dev_err(&pdev->dev, "Invalid ROM contents\n"); 82 break; 83 } 84 if (readb(image + 1) != 0xAA) 85 break; 86 /* get the PCI data structure and check its signature */ 87 pds = image + readw(image + 24); 88 if (readb(pds) != 'P') 89 break; 90 if (readb(pds + 1) != 'C') 91 break; 92 if (readb(pds + 2) != 'I') 93 break; 94 if (readb(pds + 3) != 'R') 95 break; 96 last_image = readb(pds + 21) & 0x80; 97 length = readw(pds + 16); 98 image += length * 512; 99 } while (length && !last_image); 100 101 /* never return a size larger than the PCI resource window */ 102 /* there are known ROMs that get the size wrong */ 103 return min((size_t)(image - rom), size); 104 } 105 106 /** 107 * pci_map_rom - map a PCI ROM to kernel space 108 * @pdev: pointer to pci device struct 109 * @size: pointer to receive size of pci window over ROM 110 * 111 * Return: kernel virtual pointer to image of ROM 112 * 113 * Map a PCI ROM into kernel space. If ROM is boot video ROM, 114 * the shadow BIOS copy will be returned instead of the 115 * actual ROM. 116 */ 117 void __iomem *pci_map_rom(struct pci_dev *pdev, size_t *size) 118 { 119 struct resource *res = &pdev->resource[PCI_ROM_RESOURCE]; 120 loff_t start; 121 void __iomem *rom; 122 123 /* 124 * IORESOURCE_ROM_SHADOW set on x86, x86_64 and IA64 supports legacy 125 * memory map if the VGA enable bit of the Bridge Control register is 126 * set for embedded VGA. 127 */ 128 if (res->flags & IORESOURCE_ROM_SHADOW) { 129 /* primary video rom always starts here */ 130 start = (loff_t)0xC0000; 131 *size = 0x20000; /* cover C000:0 through E000:0 */ 132 } else { 133 if (res->flags & 134 (IORESOURCE_ROM_COPY | IORESOURCE_ROM_BIOS_COPY)) { 135 *size = pci_resource_len(pdev, PCI_ROM_RESOURCE); 136 return (void __iomem *)(unsigned long) 137 pci_resource_start(pdev, PCI_ROM_RESOURCE); 138 } else { 139 /* assign the ROM an address if it doesn't have one */ 140 if (res->parent == NULL && 141 pci_assign_resource(pdev, PCI_ROM_RESOURCE)) 142 return NULL; 143 start = pci_resource_start(pdev, PCI_ROM_RESOURCE); 144 *size = pci_resource_len(pdev, PCI_ROM_RESOURCE); 145 if (*size == 0) 146 return NULL; 147 148 /* Enable ROM space decodes */ 149 if (pci_enable_rom(pdev)) 150 return NULL; 151 } 152 } 153 154 rom = ioremap(start, *size); 155 if (!rom) { 156 /* restore enable if ioremap fails */ 157 if (!(res->flags & (IORESOURCE_ROM_ENABLE | 158 IORESOURCE_ROM_SHADOW | 159 IORESOURCE_ROM_COPY))) 160 pci_disable_rom(pdev); 161 return NULL; 162 } 163 164 /* 165 * Try to find the true size of the ROM since sometimes the PCI window 166 * size is much larger than the actual size of the ROM. 167 * True size is important if the ROM is going to be copied. 168 */ 169 *size = pci_get_rom_size(pdev, rom, *size); 170 return rom; 171 } 172 EXPORT_SYMBOL(pci_map_rom); 173 174 /** 175 * pci_unmap_rom - unmap the ROM from kernel space 176 * @pdev: pointer to pci device struct 177 * @rom: virtual address of the previous mapping 178 * 179 * Remove a mapping of a previously mapped ROM 180 */ 181 void pci_unmap_rom(struct pci_dev *pdev, void __iomem *rom) 182 { 183 struct resource *res = &pdev->resource[PCI_ROM_RESOURCE]; 184 185 if (res->flags & (IORESOURCE_ROM_COPY | IORESOURCE_ROM_BIOS_COPY)) 186 return; 187 188 iounmap(rom); 189 190 /* Disable again before continuing, leave enabled if pci=rom */ 191 if (!(res->flags & (IORESOURCE_ROM_ENABLE | IORESOURCE_ROM_SHADOW))) 192 pci_disable_rom(pdev); 193 } 194 EXPORT_SYMBOL(pci_unmap_rom); 195 196 /** 197 * pci_cleanup_rom - free the ROM copy created by pci_map_rom_copy 198 * @pdev: pointer to pci device struct 199 * 200 * Free the copied ROM if we allocated one. 201 */ 202 void pci_cleanup_rom(struct pci_dev *pdev) 203 { 204 struct resource *res = &pdev->resource[PCI_ROM_RESOURCE]; 205 206 if (res->flags & IORESOURCE_ROM_COPY) { 207 kfree((void *)(unsigned long)res->start); 208 res->flags |= IORESOURCE_UNSET; 209 res->flags &= ~IORESOURCE_ROM_COPY; 210 res->start = 0; 211 res->end = 0; 212 } 213 } 214 215 /** 216 * pci_platform_rom - provides a pointer to any ROM image provided by the 217 * platform 218 * @pdev: pointer to pci device struct 219 * @size: pointer to receive size of pci window over ROM 220 */ 221 void __iomem *pci_platform_rom(struct pci_dev *pdev, size_t *size) 222 { 223 if (pdev->rom && pdev->romlen) { 224 *size = pdev->romlen; 225 return phys_to_virt((phys_addr_t)pdev->rom); 226 } 227 228 return NULL; 229 } 230 EXPORT_SYMBOL(pci_platform_rom); 231