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/pci.h> 11#include <linux/slab.h> 12 13#include "pci.h" 14 15/** 16 * pci_enable_rom - enable ROM decoding for a PCI device 17 * @pdev: PCI device to enable 18 * 19 * Enable ROM decoding on @dev. This involves simply turning on the last 20 * bit of the PCI ROM BAR. Note that some cards may share address decoders 21 * between the ROM and other resources, so enabling it may disable access 22 * to MMIO registers or other card memory. 23 */ 24int pci_enable_rom(struct pci_dev *pdev) 25{ 26 struct resource *res = pdev->resource + PCI_ROM_RESOURCE; 27 struct pci_bus_region region; 28 u32 rom_addr; 29 30 if (!res->flags) 31 return -1; 32 33 pcibios_resource_to_bus(pdev, ®ion, res); 34 pci_read_config_dword(pdev, pdev->rom_base_reg, &rom_addr); 35 rom_addr &= ~PCI_ROM_ADDRESS_MASK; 36 rom_addr |= region.start | PCI_ROM_ADDRESS_ENABLE; 37 pci_write_config_dword(pdev, pdev->rom_base_reg, rom_addr); 38 return 0; 39} 40 41/** 42 * pci_disable_rom - disable ROM decoding for a PCI device 43 * @pdev: PCI device to disable 44 * 45 * Disable ROM decoding on a PCI device by turning off the last bit in the 46 * ROM BAR. 47 */ 48void pci_disable_rom(struct pci_dev *pdev) 49{ 50 u32 rom_addr; 51 pci_read_config_dword(pdev, pdev->rom_base_reg, &rom_addr); 52 rom_addr &= ~PCI_ROM_ADDRESS_ENABLE; 53 pci_write_config_dword(pdev, pdev->rom_base_reg, rom_addr); 54} 55 56/** 57 * pci_get_rom_size - obtain the actual size of the ROM image 58 * @pdev: target PCI device 59 * @rom: kernel virtual pointer to image of ROM 60 * @size: size of PCI window 61 * return: size of actual ROM image 62 * 63 * Determine the actual length of the ROM image. 64 * The PCI window size could be much larger than the 65 * actual image size. 66 */ 67size_t pci_get_rom_size(struct pci_dev *pdev, void __iomem *rom, size_t size) 68{ 69 void __iomem *image; 70 int last_image; 71 72 image = rom; 73 do { 74 void __iomem *pds; 75 /* Standard PCI ROMs start out with these bytes 55 AA */ 76 if (readb(image) != 0x55) { 77 dev_err(&pdev->dev, "Invalid ROM contents\n"); 78 break; 79 } 80 if (readb(image + 1) != 0xAA) 81 break; 82 /* get the PCI data structure and check its signature */ 83 pds = image + readw(image + 24); 84 if (readb(pds) != 'P') 85 break; 86 if (readb(pds + 1) != 'C') 87 break; 88 if (readb(pds + 2) != 'I') 89 break; 90 if (readb(pds + 3) != 'R') 91 break; 92 last_image = readb(pds + 21) & 0x80; 93 /* this length is reliable */ 94 image += readw(pds + 16) * 512; 95 } while (!last_image); 96 97 /* never return a size larger than the PCI resource window */ 98 /* there are known ROMs that get the size wrong */ 99 return min((size_t)(image - rom), size); 100} 101 102/** 103 * pci_map_rom - map a PCI ROM to kernel space 104 * @pdev: pointer to pci device struct 105 * @size: pointer to receive size of pci window over ROM 106 * 107 * Return: kernel virtual pointer to image of ROM 108 * 109 * Map a PCI ROM into kernel space. If ROM is boot video ROM, 110 * the shadow BIOS copy will be returned instead of the 111 * actual ROM. 112 */ 113void __iomem *pci_map_rom(struct pci_dev *pdev, size_t *size) 114{ 115 struct resource *res = &pdev->resource[PCI_ROM_RESOURCE]; 116 loff_t start; 117 void __iomem *rom; 118 119 /* 120 * IORESOURCE_ROM_SHADOW set on x86, x86_64 and IA64 supports legacy 121 * memory map if the VGA enable bit of the Bridge Control register is 122 * set for embedded VGA. 123 */ 124 if (res->flags & IORESOURCE_ROM_SHADOW) { 125 /* primary video rom always starts here */ 126 start = (loff_t)0xC0000; 127 *size = 0x20000; /* cover C000:0 through E000:0 */ 128 } else { 129 if (res->flags & 130 (IORESOURCE_ROM_COPY | IORESOURCE_ROM_BIOS_COPY)) { 131 *size = pci_resource_len(pdev, PCI_ROM_RESOURCE); 132 return (void __iomem *)(unsigned long) 133 pci_resource_start(pdev, PCI_ROM_RESOURCE); 134 } else { 135 /* assign the ROM an address if it doesn't have one */ 136 if (res->parent == NULL && 137 pci_assign_resource(pdev,PCI_ROM_RESOURCE)) 138 return NULL; 139 start = pci_resource_start(pdev, PCI_ROM_RESOURCE); 140 *size = pci_resource_len(pdev, PCI_ROM_RESOURCE); 141 if (*size == 0) 142 return NULL; 143 144 /* Enable ROM space decodes */ 145 if (pci_enable_rom(pdev)) 146 return NULL; 147 } 148 } 149 150 rom = ioremap(start, *size); 151 if (!rom) { 152 /* restore enable if ioremap fails */ 153 if (!(res->flags & (IORESOURCE_ROM_ENABLE | 154 IORESOURCE_ROM_SHADOW | 155 IORESOURCE_ROM_COPY))) 156 pci_disable_rom(pdev); 157 return NULL; 158 } 159 160 /* 161 * Try to find the true size of the ROM since sometimes the PCI window 162 * size is much larger than the actual size of the ROM. 163 * True size is important if the ROM is going to be copied. 164 */ 165 *size = pci_get_rom_size(pdev, rom, *size); 166 return rom; 167} 168 169 170/** 171 * pci_unmap_rom - unmap the ROM from kernel space 172 * @pdev: pointer to pci device struct 173 * @rom: virtual address of the previous mapping 174 * 175 * Remove a mapping of a previously mapped ROM 176 */ 177void pci_unmap_rom(struct pci_dev *pdev, void __iomem *rom) 178{ 179 struct resource *res = &pdev->resource[PCI_ROM_RESOURCE]; 180 181 if (res->flags & (IORESOURCE_ROM_COPY | IORESOURCE_ROM_BIOS_COPY)) 182 return; 183 184 iounmap(rom); 185 186 /* Disable again before continuing, leave enabled if pci=rom */ 187 if (!(res->flags & (IORESOURCE_ROM_ENABLE | IORESOURCE_ROM_SHADOW))) 188 pci_disable_rom(pdev); 189} 190 191 192/** 193 * pci_cleanup_rom - free the ROM copy created by pci_map_rom_copy 194 * @pdev: pointer to pci device struct 195 * 196 * Free the copied ROM if we allocated one. 197 */ 198void pci_cleanup_rom(struct pci_dev *pdev) 199{ 200 struct resource *res = &pdev->resource[PCI_ROM_RESOURCE]; 201 if (res->flags & IORESOURCE_ROM_COPY) { 202 kfree((void*)(unsigned long)res->start); 203 res->flags &= ~IORESOURCE_ROM_COPY; 204 res->start = 0; 205 res->end = 0; 206 } 207} 208 209EXPORT_SYMBOL(pci_map_rom); 210EXPORT_SYMBOL(pci_unmap_rom); 211EXPORT_SYMBOL_GPL(pci_enable_rom); 212EXPORT_SYMBOL_GPL(pci_disable_rom); 213