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 /* Nothing to enable if we're using a shadow copy in RAM */ 35 if (res->flags & IORESOURCE_ROM_SHADOW) 36 return 0; 37 38 /* 39 * Ideally pci_update_resource() would update the ROM BAR address, 40 * and we would only set the enable bit here. But apparently some 41 * devices have buggy ROM BARs that read as zero when disabled. 42 */ 43 pcibios_resource_to_bus(pdev->bus, ®ion, res); 44 pci_read_config_dword(pdev, pdev->rom_base_reg, &rom_addr); 45 rom_addr &= ~PCI_ROM_ADDRESS_MASK; 46 rom_addr |= region.start | PCI_ROM_ADDRESS_ENABLE; 47 pci_write_config_dword(pdev, pdev->rom_base_reg, rom_addr); 48 return 0; 49 } 50 EXPORT_SYMBOL_GPL(pci_enable_rom); 51 52 /** 53 * pci_disable_rom - disable ROM decoding for a PCI device 54 * @pdev: PCI device to disable 55 * 56 * Disable ROM decoding on a PCI device by turning off the last bit in the 57 * ROM BAR. 58 */ 59 void pci_disable_rom(struct pci_dev *pdev) 60 { 61 struct resource *res = &pdev->resource[PCI_ROM_RESOURCE]; 62 u32 rom_addr; 63 64 if (res->flags & IORESOURCE_ROM_SHADOW) 65 return; 66 67 pci_read_config_dword(pdev, pdev->rom_base_reg, &rom_addr); 68 rom_addr &= ~PCI_ROM_ADDRESS_ENABLE; 69 pci_write_config_dword(pdev, pdev->rom_base_reg, rom_addr); 70 } 71 EXPORT_SYMBOL_GPL(pci_disable_rom); 72 73 /** 74 * pci_get_rom_size - obtain the actual size of the ROM image 75 * @pdev: target PCI device 76 * @rom: kernel virtual pointer to image of ROM 77 * @size: size of PCI window 78 * return: size of actual ROM image 79 * 80 * Determine the actual length of the ROM image. 81 * The PCI window size could be much larger than the 82 * actual image size. 83 */ 84 size_t pci_get_rom_size(struct pci_dev *pdev, void __iomem *rom, size_t size) 85 { 86 void __iomem *image; 87 int last_image; 88 unsigned length; 89 90 image = rom; 91 do { 92 void __iomem *pds; 93 /* Standard PCI ROMs start out with these bytes 55 AA */ 94 if (readw(image) != 0xAA55) { 95 dev_err(&pdev->dev, "Invalid PCI ROM header signature: expecting 0xaa55, got %#06x\n", 96 readw(image)); 97 break; 98 } 99 /* get the PCI data structure and check its "PCIR" signature */ 100 pds = image + readw(image + 24); 101 if (readl(pds) != 0x52494350) { 102 dev_err(&pdev->dev, "Invalid PCI ROM data signature: expecting 0x52494350, got %#010x\n", 103 readl(pds)); 104 break; 105 } 106 last_image = readb(pds + 21) & 0x80; 107 length = readw(pds + 16); 108 image += length * 512; 109 /* Avoid iterating through memory outside the resource window */ 110 if (image > rom + size) 111 break; 112 } while (length && !last_image); 113 114 /* never return a size larger than the PCI resource window */ 115 /* there are known ROMs that get the size wrong */ 116 return min((size_t)(image - rom), size); 117 } 118 119 /** 120 * pci_map_rom - map a PCI ROM to kernel space 121 * @pdev: pointer to pci device struct 122 * @size: pointer to receive size of pci window over ROM 123 * 124 * Return: kernel virtual pointer to image of ROM 125 * 126 * Map a PCI ROM into kernel space. If ROM is boot video ROM, 127 * the shadow BIOS copy will be returned instead of the 128 * actual ROM. 129 */ 130 void __iomem *pci_map_rom(struct pci_dev *pdev, size_t *size) 131 { 132 struct resource *res = &pdev->resource[PCI_ROM_RESOURCE]; 133 loff_t start; 134 void __iomem *rom; 135 136 /* assign the ROM an address if it doesn't have one */ 137 if (res->parent == NULL && pci_assign_resource(pdev, PCI_ROM_RESOURCE)) 138 return NULL; 139 140 start = pci_resource_start(pdev, PCI_ROM_RESOURCE); 141 *size = pci_resource_len(pdev, PCI_ROM_RESOURCE); 142 if (*size == 0) 143 return NULL; 144 145 /* Enable ROM space decodes */ 146 if (pci_enable_rom(pdev)) 147 return NULL; 148 149 rom = ioremap(start, *size); 150 if (!rom) 151 goto err_ioremap; 152 153 /* 154 * Try to find the true size of the ROM since sometimes the PCI window 155 * size is much larger than the actual size of the ROM. 156 * True size is important if the ROM is going to be copied. 157 */ 158 *size = pci_get_rom_size(pdev, rom, *size); 159 if (!*size) 160 goto invalid_rom; 161 162 return rom; 163 164 invalid_rom: 165 iounmap(rom); 166 err_ioremap: 167 /* restore enable if ioremap fails */ 168 if (!(res->flags & IORESOURCE_ROM_ENABLE)) 169 pci_disable_rom(pdev); 170 return NULL; 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 iounmap(rom); 186 187 /* Disable again before continuing */ 188 if (!(res->flags & IORESOURCE_ROM_ENABLE)) 189 pci_disable_rom(pdev); 190 } 191 EXPORT_SYMBOL(pci_unmap_rom); 192 193 /** 194 * pci_platform_rom - provides a pointer to any ROM image provided by the 195 * platform 196 * @pdev: pointer to pci device struct 197 * @size: pointer to receive size of pci window over ROM 198 */ 199 void __iomem *pci_platform_rom(struct pci_dev *pdev, size_t *size) 200 { 201 if (pdev->rom && pdev->romlen) { 202 *size = pdev->romlen; 203 return phys_to_virt((phys_addr_t)pdev->rom); 204 } 205 206 return NULL; 207 } 208 EXPORT_SYMBOL(pci_platform_rom); 209