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/*
* drivers/pci/rom.c
*
* (C) Copyright 2004 Jon Smirl <jonsmirl@yahoo.com>
* (C) Copyright 2004 Silicon Graphics, Inc. Jesse Barnes <jbarnes@sgi.com>
*
* PCI ROM access routines
*/
#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;
pcibios_resource_to_bus(pdev, ®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;
}
/**
* 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)
{
u32 rom_addr;
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);
}
/**
* 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.
*/
size_t pci_get_rom_size(struct pci_dev *pdev, void __iomem *rom, size_t size)
{
void __iomem *image;
int last_image;
image = rom;
do {
void __iomem *pds;
/* Standard PCI ROMs start out with these bytes 55 AA */
if (readb(image) != 0x55) {
dev_err(&pdev->dev, "Invalid ROM contents\n");
break;
}
if (readb(image + 1) != 0xAA)
break;
/* get the PCI data structure and check its signature */
pds = image + readw(image + 24);
if (readb(pds) != 'P')
break;
if (readb(pds + 1) != 'C')
break;
if (readb(pds + 2) != 'I')
break;
if (readb(pds + 3) != 'R')
break;
last_image = readb(pds + 21) & 0x80;
/* this length is reliable */
image += readw(pds + 16) * 512;
} while (!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);
}
static loff_t pci_find_rom(struct pci_dev *pdev, size_t *size)
{
struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
loff_t start;
/* assign the ROM an address if it doesn't have one */
if (res->parent == NULL && pci_assign_resource(pdev, PCI_ROM_RESOURCE))
return 0;
start = pci_resource_start(pdev, PCI_ROM_RESOURCE);
*size = pci_resource_len(pdev, PCI_ROM_RESOURCE);
if (*size == 0)
return 0;
/* Enable ROM space decodes */
if (pci_enable_rom(pdev))
return 0;
return start;
}
/**
* 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 = 0;
void __iomem *rom;
/*
* IORESOURCE_ROM_SHADOW set on x86, x86_64 and IA64 supports legacy
* memory map if the VGA enable bit of the Bridge Control register is
* set for embedded VGA.
*/
if (res->flags & IORESOURCE_ROM_SHADOW) {
/* primary video rom always starts here */
start = (loff_t)0xC0000;
*size = 0x20000; /* cover C000:0 through E000:0 */
} else {
if (res->flags &
(IORESOURCE_ROM_COPY | IORESOURCE_ROM_BIOS_COPY)) {
*size = pci_resource_len(pdev, PCI_ROM_RESOURCE);
return (void __iomem *)(unsigned long)
pci_resource_start(pdev, PCI_ROM_RESOURCE);
} else {
start = pci_find_rom(pdev, size);
}
}
/*
* Some devices may provide ROMs via a source other than the BAR
*/
if (!start && pdev->rom && pdev->romlen) {
*size = pdev->romlen;
return phys_to_virt(pdev->rom);
}
if (!start)
return NULL;
rom = ioremap(start, *size);
if (!rom) {
/* restore enable if ioremap fails */
if (!(res->flags & (IORESOURCE_ROM_ENABLE |
IORESOURCE_ROM_SHADOW |
IORESOURCE_ROM_COPY)))
pci_disable_rom(pdev);
return NULL;
}
/*
* 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);
return 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];
if (res->flags & (IORESOURCE_ROM_COPY | IORESOURCE_ROM_BIOS_COPY))
return;
if (!pdev->rom || !pdev->romlen)
iounmap(rom);
/* Disable again before continuing, leave enabled if pci=rom */
if (!(res->flags & (IORESOURCE_ROM_ENABLE | IORESOURCE_ROM_SHADOW)))
pci_disable_rom(pdev);
}
/**
* pci_cleanup_rom - free the ROM copy created by pci_map_rom_copy
* @pdev: pointer to pci device struct
*
* Free the copied ROM if we allocated one.
*/
void pci_cleanup_rom(struct pci_dev *pdev)
{
struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
if (res->flags & IORESOURCE_ROM_COPY) {
kfree((void*)(unsigned long)res->start);
res->flags &= ~IORESOURCE_ROM_COPY;
res->start = 0;
res->end = 0;
}
}
EXPORT_SYMBOL(pci_map_rom);
EXPORT_SYMBOL(pci_unmap_rom);
EXPORT_SYMBOL_GPL(pci_enable_rom);
EXPORT_SYMBOL_GPL(pci_disable_rom);
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