| 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); |