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