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 pcibios_resource_to_bus(pdev->bus, ®ion, res); 39 pci_read_config_dword(pdev, pdev->rom_base_reg, &rom_addr); 40 rom_addr &= ~PCI_ROM_ADDRESS_MASK; 41 rom_addr |= region.start | PCI_ROM_ADDRESS_ENABLE; 42 pci_write_config_dword(pdev, pdev->rom_base_reg, rom_addr); 43 return 0; 44 } 45 EXPORT_SYMBOL_GPL(pci_enable_rom); 46 47 /** 48 * pci_disable_rom - disable ROM decoding for a PCI device 49 * @pdev: PCI device to disable 50 * 51 * Disable ROM decoding on a PCI device by turning off the last bit in the 52 * ROM BAR. 53 */ 54 void pci_disable_rom(struct pci_dev *pdev) 55 { 56 struct resource *res = &pdev->resource[PCI_ROM_RESOURCE]; 57 u32 rom_addr; 58 59 if (res->flags & IORESOURCE_ROM_SHADOW) 60 return; 61 62 pci_read_config_dword(pdev, pdev->rom_base_reg, &rom_addr); 63 rom_addr &= ~PCI_ROM_ADDRESS_ENABLE; 64 pci_write_config_dword(pdev, pdev->rom_base_reg, rom_addr); 65 } 66 EXPORT_SYMBOL_GPL(pci_disable_rom); 67 68 /** 69 * pci_get_rom_size - obtain the actual size of the ROM image 70 * @pdev: target PCI device 71 * @rom: kernel virtual pointer to image of ROM 72 * @size: size of PCI window 73 * return: size of actual ROM image 74 * 75 * Determine the actual length of the ROM image. 76 * The PCI window size could be much larger than the 77 * actual image size. 78 */ 79 size_t pci_get_rom_size(struct pci_dev *pdev, void __iomem *rom, size_t size) 80 { 81 void __iomem *image; 82 int last_image; 83 unsigned length; 84 85 image = rom; 86 do { 87 void __iomem *pds; 88 /* Standard PCI ROMs start out with these bytes 55 AA */ 89 if (readw(image) != 0xAA55) { 90 dev_err(&pdev->dev, "Invalid PCI ROM header signature: expecting 0xaa55, got %#06x\n", 91 readw(image)); 92 break; 93 } 94 /* get the PCI data structure and check its "PCIR" signature */ 95 pds = image + readw(image + 24); 96 if (readl(pds) != 0x52494350) { 97 dev_err(&pdev->dev, "Invalid PCI ROM data signature: expecting 0x52494350, got %#010x\n", 98 readl(pds)); 99 break; 100 } 101 last_image = readb(pds + 21) & 0x80; 102 length = readw(pds + 16); 103 image += length * 512; 104 /* Avoid iterating through memory outside the resource window */ 105 if (image > rom + size) 106 break; 107 } while (length && !last_image); 108 109 /* never return a size larger than the PCI resource window */ 110 /* there are known ROMs that get the size wrong */ 111 return min((size_t)(image - rom), size); 112 } 113 114 /** 115 * pci_map_rom - map a PCI ROM to kernel space 116 * @pdev: pointer to pci device struct 117 * @size: pointer to receive size of pci window over ROM 118 * 119 * Return: kernel virtual pointer to image of ROM 120 * 121 * Map a PCI ROM into kernel space. If ROM is boot video ROM, 122 * the shadow BIOS copy will be returned instead of the 123 * actual ROM. 124 */ 125 void __iomem *pci_map_rom(struct pci_dev *pdev, size_t *size) 126 { 127 struct resource *res = &pdev->resource[PCI_ROM_RESOURCE]; 128 loff_t start; 129 void __iomem *rom; 130 131 /* assign the ROM an address if it doesn't have one */ 132 if (res->parent == NULL && pci_assign_resource(pdev, PCI_ROM_RESOURCE)) 133 return NULL; 134 135 start = pci_resource_start(pdev, PCI_ROM_RESOURCE); 136 *size = pci_resource_len(pdev, PCI_ROM_RESOURCE); 137 if (*size == 0) 138 return NULL; 139 140 /* Enable ROM space decodes */ 141 if (pci_enable_rom(pdev)) 142 return NULL; 143 144 rom = ioremap(start, *size); 145 if (!rom) { 146 /* restore enable if ioremap fails */ 147 if (!(res->flags & IORESOURCE_ROM_ENABLE)) 148 pci_disable_rom(pdev); 149 return NULL; 150 } 151 152 /* 153 * Try to find the true size of the ROM since sometimes the PCI window 154 * size is much larger than the actual size of the ROM. 155 * True size is important if the ROM is going to be copied. 156 */ 157 *size = pci_get_rom_size(pdev, rom, *size); 158 return rom; 159 } 160 EXPORT_SYMBOL(pci_map_rom); 161 162 /** 163 * pci_unmap_rom - unmap the ROM from kernel space 164 * @pdev: pointer to pci device struct 165 * @rom: virtual address of the previous mapping 166 * 167 * Remove a mapping of a previously mapped ROM 168 */ 169 void pci_unmap_rom(struct pci_dev *pdev, void __iomem *rom) 170 { 171 struct resource *res = &pdev->resource[PCI_ROM_RESOURCE]; 172 173 iounmap(rom); 174 175 /* Disable again before continuing */ 176 if (!(res->flags & IORESOURCE_ROM_ENABLE)) 177 pci_disable_rom(pdev); 178 } 179 EXPORT_SYMBOL(pci_unmap_rom); 180 181 /** 182 * pci_platform_rom - provides a pointer to any ROM image provided by the 183 * platform 184 * @pdev: pointer to pci device struct 185 * @size: pointer to receive size of pci window over ROM 186 */ 187 void __iomem *pci_platform_rom(struct pci_dev *pdev, size_t *size) 188 { 189 if (pdev->rom && pdev->romlen) { 190 *size = pdev->romlen; 191 return phys_to_virt((phys_addr_t)pdev->rom); 192 } 193 194 return NULL; 195 } 196 EXPORT_SYMBOL(pci_platform_rom); 197