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df62ab5e0f
Remove pointless comments that tell us the file name, remove blank line comments, follow multi-line comment conventions. No functional change intended. Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
208 lines
5.6 KiB
C
208 lines
5.6 KiB
C
// 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 <jonsmirl@yahoo.com>
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* (C) Copyright 2004 Silicon Graphics, Inc. Jesse Barnes <jbarnes@sgi.com>
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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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size_t pci_get_rom_size(struct pci_dev *pdev, void __iomem *rom, 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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} 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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/**
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* pci_platform_rom - provides a pointer to any ROM image provided by the
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* platform
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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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void __iomem *pci_platform_rom(struct pci_dev *pdev, size_t *size)
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{
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if (pdev->rom && pdev->romlen) {
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*size = pdev->romlen;
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return phys_to_virt((phys_addr_t)pdev->rom);
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}
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return NULL;
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}
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EXPORT_SYMBOL(pci_platform_rom);
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