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