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![Michel Dänzer](/assets/img/avatar_default.png)
If the image size would ever read as 0, pci_get_rom_size() could keep processing the same image over and over again. Exit the loop if we ever read a length of zero. This fixes a soft lockup on boot when the radeon driver calls pci_get_rom_size() on an AMD Radeon R7 250X PCIe discrete graphics card. [bhelgaas: changelog, reference] Link: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1386973 Reported-by: Federico <federicotg@gmail.com> Signed-off-by: Michel Dänzer <michel.daenzer@amd.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Alex Deucher <alexander.deucher@amd.com> CC: stable@vger.kernel.org
230 lines
6.2 KiB
C
230 lines
6.2 KiB
C
/*
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* drivers/pci/rom.c
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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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* PCI ROM access routines
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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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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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u32 rom_addr;
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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 (readb(image) != 0x55) {
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dev_err(&pdev->dev, "Invalid ROM contents\n");
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break;
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}
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if (readb(image + 1) != 0xAA)
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break;
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/* get the PCI data structure and check its signature */
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pds = image + readw(image + 24);
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if (readb(pds) != 'P')
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break;
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if (readb(pds + 1) != 'C')
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break;
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if (readb(pds + 2) != 'I')
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break;
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if (readb(pds + 3) != 'R')
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break;
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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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} 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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/*
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* IORESOURCE_ROM_SHADOW set on x86, x86_64 and IA64 supports legacy
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* memory map if the VGA enable bit of the Bridge Control register is
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* set for embedded VGA.
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*/
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if (res->flags & IORESOURCE_ROM_SHADOW) {
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/* primary video rom always starts here */
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start = (loff_t)0xC0000;
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*size = 0x20000; /* cover C000:0 through E000:0 */
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} else {
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if (res->flags &
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(IORESOURCE_ROM_COPY | IORESOURCE_ROM_BIOS_COPY)) {
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*size = pci_resource_len(pdev, PCI_ROM_RESOURCE);
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return (void __iomem *)(unsigned long)
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pci_resource_start(pdev, PCI_ROM_RESOURCE);
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} else {
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/* assign the ROM an address if it doesn't have one */
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if (res->parent == NULL &&
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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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}
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}
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rom = ioremap(start, *size);
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if (!rom) {
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/* restore enable if ioremap fails */
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if (!(res->flags & (IORESOURCE_ROM_ENABLE |
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IORESOURCE_ROM_SHADOW |
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IORESOURCE_ROM_COPY)))
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pci_disable_rom(pdev);
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return NULL;
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}
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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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return rom;
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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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if (res->flags & (IORESOURCE_ROM_COPY | IORESOURCE_ROM_BIOS_COPY))
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return;
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iounmap(rom);
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/* Disable again before continuing, leave enabled if pci=rom */
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if (!(res->flags & (IORESOURCE_ROM_ENABLE | IORESOURCE_ROM_SHADOW)))
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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_cleanup_rom - free the ROM copy created by pci_map_rom_copy
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* @pdev: pointer to pci device struct
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*
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* Free the copied ROM if we allocated one.
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*/
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void pci_cleanup_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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if (res->flags & IORESOURCE_ROM_COPY) {
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kfree((void *)(unsigned long)res->start);
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res->flags |= IORESOURCE_UNSET;
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res->flags &= ~IORESOURCE_ROM_COPY;
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res->start = 0;
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res->end = 0;
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}
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}
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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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