diff options
Diffstat (limited to 'drivers/pci/rom.c')
| -rw-r--r-- | drivers/pci/rom.c | 197 |
1 files changed, 197 insertions, 0 deletions
diff --git a/drivers/pci/rom.c b/drivers/pci/rom.c new file mode 100644 index 000000000..e18d3a438 --- /dev/null +++ b/drivers/pci/rom.c @@ -0,0 +1,197 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * PCI ROM access routines + * + * (C) Copyright 2004 Jon Smirl <jonsmirl@yahoo.com> + * (C) Copyright 2004 Silicon Graphics, Inc. Jesse Barnes <jbarnes@sgi.com> + */ +#include <linux/kernel.h> +#include <linux/export.h> +#include <linux/pci.h> +#include <linux/slab.h> + +#include "pci.h" + +/** + * pci_enable_rom - enable ROM decoding for a PCI device + * @pdev: PCI device to enable + * + * Enable ROM decoding on @dev. This involves simply turning on the last + * bit of the PCI ROM BAR. Note that some cards may share address decoders + * between the ROM and other resources, so enabling it may disable access + * to MMIO registers or other card memory. + */ +int pci_enable_rom(struct pci_dev *pdev) +{ + struct resource *res = &pdev->resource[PCI_ROM_RESOURCE]; + struct pci_bus_region region; + u32 rom_addr; + + if (!res->flags) + return -1; + + /* Nothing to enable if we're using a shadow copy in RAM */ + if (res->flags & IORESOURCE_ROM_SHADOW) + return 0; + + /* + * Ideally pci_update_resource() would update the ROM BAR address, + * and we would only set the enable bit here. But apparently some + * devices have buggy ROM BARs that read as zero when disabled. + */ + pcibios_resource_to_bus(pdev->bus, ®ion, res); + pci_read_config_dword(pdev, pdev->rom_base_reg, &rom_addr); + rom_addr &= ~PCI_ROM_ADDRESS_MASK; + rom_addr |= region.start | PCI_ROM_ADDRESS_ENABLE; + pci_write_config_dword(pdev, pdev->rom_base_reg, rom_addr); + return 0; +} +EXPORT_SYMBOL_GPL(pci_enable_rom); + +/** + * pci_disable_rom - disable ROM decoding for a PCI device + * @pdev: PCI device to disable + * + * Disable ROM decoding on a PCI device by turning off the last bit in the + * ROM BAR. + */ +void pci_disable_rom(struct pci_dev *pdev) +{ + struct resource *res = &pdev->resource[PCI_ROM_RESOURCE]; + u32 rom_addr; + + if (res->flags & IORESOURCE_ROM_SHADOW) + return; + + pci_read_config_dword(pdev, pdev->rom_base_reg, &rom_addr); + rom_addr &= ~PCI_ROM_ADDRESS_ENABLE; + pci_write_config_dword(pdev, pdev->rom_base_reg, rom_addr); +} +EXPORT_SYMBOL_GPL(pci_disable_rom); + +/** + * pci_get_rom_size - obtain the actual size of the ROM image + * @pdev: target PCI device + * @rom: kernel virtual pointer to image of ROM + * @size: size of PCI window + * return: size of actual ROM image + * + * Determine the actual length of the ROM image. + * The PCI window size could be much larger than the + * actual image size. + */ +static size_t pci_get_rom_size(struct pci_dev *pdev, void __iomem *rom, + size_t size) +{ + void __iomem *image; + int last_image; + unsigned int length; + + image = rom; + do { + void __iomem *pds; + /* Standard PCI ROMs start out with these bytes 55 AA */ + if (readw(image) != 0xAA55) { + pci_info(pdev, "Invalid PCI ROM header signature: expecting 0xaa55, got %#06x\n", + readw(image)); + break; + } + /* get the PCI data structure and check its "PCIR" signature */ + pds = image + readw(image + 24); + if (readl(pds) != 0x52494350) { + pci_info(pdev, "Invalid PCI ROM data signature: expecting 0x52494350, got %#010x\n", + readl(pds)); + break; + } + last_image = readb(pds + 21) & 0x80; + length = readw(pds + 16); + image += length * 512; + /* Avoid iterating through memory outside the resource window */ + if (image >= rom + size) + break; + if (!last_image) { + if (readw(image) != 0xAA55) { + pci_info(pdev, "No more image in the PCI ROM\n"); + break; + } + } + } while (length && !last_image); + + /* never return a size larger than the PCI resource window */ + /* there are known ROMs that get the size wrong */ + return min((size_t)(image - rom), size); +} + +/** + * pci_map_rom - map a PCI ROM to kernel space + * @pdev: pointer to pci device struct + * @size: pointer to receive size of pci window over ROM + * + * Return: kernel virtual pointer to image of ROM + * + * Map a PCI ROM into kernel space. If ROM is boot video ROM, + * the shadow BIOS copy will be returned instead of the + * actual ROM. + */ +void __iomem *pci_map_rom(struct pci_dev *pdev, size_t *size) +{ + struct resource *res = &pdev->resource[PCI_ROM_RESOURCE]; + loff_t start; + void __iomem *rom; + + /* assign the ROM an address if it doesn't have one */ + if (res->parent == NULL && pci_assign_resource(pdev, PCI_ROM_RESOURCE)) + return NULL; + + start = pci_resource_start(pdev, PCI_ROM_RESOURCE); + *size = pci_resource_len(pdev, PCI_ROM_RESOURCE); + if (*size == 0) + return NULL; + + /* Enable ROM space decodes */ + if (pci_enable_rom(pdev)) + return NULL; + + rom = ioremap(start, *size); + if (!rom) + goto err_ioremap; + + /* + * Try to find the true size of the ROM since sometimes the PCI window + * size is much larger than the actual size of the ROM. + * True size is important if the ROM is going to be copied. + */ + *size = pci_get_rom_size(pdev, rom, *size); + if (!*size) + goto invalid_rom; + + return rom; + +invalid_rom: + iounmap(rom); +err_ioremap: + /* restore enable if ioremap fails */ + if (!(res->flags & IORESOURCE_ROM_ENABLE)) + pci_disable_rom(pdev); + return NULL; +} +EXPORT_SYMBOL(pci_map_rom); + +/** + * pci_unmap_rom - unmap the ROM from kernel space + * @pdev: pointer to pci device struct + * @rom: virtual address of the previous mapping + * + * Remove a mapping of a previously mapped ROM + */ +void pci_unmap_rom(struct pci_dev *pdev, void __iomem *rom) +{ + struct resource *res = &pdev->resource[PCI_ROM_RESOURCE]; + + iounmap(rom); + + /* Disable again before continuing */ + if (!(res->flags & IORESOURCE_ROM_ENABLE)) + pci_disable_rom(pdev); +} +EXPORT_SYMBOL(pci_unmap_rom); |