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 /** 104 * pci_map_rom - map a PCI ROM to kernel space 105 * @pdev: pointer to pci device struct 106 * @size: pointer to receive size of pci window over ROM 107 * 108 * Return: kernel virtual pointer to image of ROM 109 * 110 * Map a PCI ROM into kernel space. If ROM is boot video ROM, 111 * the shadow BIOS copy will be returned instead of the 112 * actual ROM. 113 */ 114 void __iomem *pci_map_rom(struct pci_dev *pdev, size_t *size) 115 { 116 struct resource *res = &pdev->resource[PCI_ROM_RESOURCE]; 117 loff_t start; 118 void __iomem *rom; 119 120 /* 121 * Some devices may provide ROMs via a source other than the BAR 122 */ 123 if (pdev->rom && pdev->romlen) { 124 *size = pdev->romlen; 125 return phys_to_virt(pdev->rom); 126 /* 127 * IORESOURCE_ROM_SHADOW set on x86, x86_64 and IA64 supports legacy 128 * memory map if the VGA enable bit of the Bridge Control register is 129 * set for embedded VGA. 130 */ 131 } else if (res->flags & IORESOURCE_ROM_SHADOW) { 132 /* primary video rom always starts here */ 133 start = (loff_t)0xC0000; 134 *size = 0x20000; /* cover C000:0 through E000:0 */ 135 } else { 136 if (res->flags & 137 (IORESOURCE_ROM_COPY | IORESOURCE_ROM_BIOS_COPY)) { 138 *size = pci_resource_len(pdev, PCI_ROM_RESOURCE); 139 return (void __iomem *)(unsigned long) 140 pci_resource_start(pdev, PCI_ROM_RESOURCE); 141 } else { 142 /* assign the ROM an address if it doesn't have one */ 143 if (res->parent == NULL && 144 pci_assign_resource(pdev,PCI_ROM_RESOURCE)) 145 return NULL; 146 start = pci_resource_start(pdev, PCI_ROM_RESOURCE); 147 *size = pci_resource_len(pdev, PCI_ROM_RESOURCE); 148 if (*size == 0) 149 return NULL; 150 151 /* Enable ROM space decodes */ 152 if (pci_enable_rom(pdev)) 153 return NULL; 154 } 155 } 156 157 rom = ioremap(start, *size); 158 if (!rom) { 159 /* restore enable if ioremap fails */ 160 if (!(res->flags & (IORESOURCE_ROM_ENABLE | 161 IORESOURCE_ROM_SHADOW | 162 IORESOURCE_ROM_COPY))) 163 pci_disable_rom(pdev); 164 return NULL; 165 } 166 167 /* 168 * Try to find the true size of the ROM since sometimes the PCI window 169 * size is much larger than the actual size of the ROM. 170 * True size is important if the ROM is going to be copied. 171 */ 172 *size = pci_get_rom_size(pdev, rom, *size); 173 return rom; 174 } 175 176 /** 177 * pci_unmap_rom - unmap the ROM from kernel space 178 * @pdev: pointer to pci device struct 179 * @rom: virtual address of the previous mapping 180 * 181 * Remove a mapping of a previously mapped ROM 182 */ 183 void pci_unmap_rom(struct pci_dev *pdev, void __iomem *rom) 184 { 185 struct resource *res = &pdev->resource[PCI_ROM_RESOURCE]; 186 187 if (res->flags & (IORESOURCE_ROM_COPY | IORESOURCE_ROM_BIOS_COPY)) 188 return; 189 190 if (!pdev->rom || !pdev->romlen) 191 iounmap(rom); 192 193 /* Disable again before continuing, leave enabled if pci=rom */ 194 if (!(res->flags & (IORESOURCE_ROM_ENABLE | IORESOURCE_ROM_SHADOW))) 195 pci_disable_rom(pdev); 196 } 197 198 /** 199 * pci_cleanup_rom - free the ROM copy created by pci_map_rom_copy 200 * @pdev: pointer to pci device struct 201 * 202 * Free the copied ROM if we allocated one. 203 */ 204 void pci_cleanup_rom(struct pci_dev *pdev) 205 { 206 struct resource *res = &pdev->resource[PCI_ROM_RESOURCE]; 207 if (res->flags & IORESOURCE_ROM_COPY) { 208 kfree((void*)(unsigned long)res->start); 209 res->flags &= ~IORESOURCE_ROM_COPY; 210 res->start = 0; 211 res->end = 0; 212 } 213 } 214 215 EXPORT_SYMBOL(pci_map_rom); 216 EXPORT_SYMBOL(pci_unmap_rom); 217 EXPORT_SYMBOL_GPL(pci_enable_rom); 218 EXPORT_SYMBOL_GPL(pci_disable_rom); 219