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path: root/drivers/pci/rom.c
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Diffstat (limited to 'drivers/pci/rom.c')
-rw-r--r--drivers/pci/rom.c73
1 files changed, 44 insertions, 29 deletions
diff --git a/drivers/pci/rom.c b/drivers/pci/rom.c
index d087e0817715..dbbcc04abd1a 100644
--- a/drivers/pci/rom.c
+++ b/drivers/pci/rom.c
@@ -54,6 +54,49 @@ static void pci_disable_rom(struct pci_dev *pdev)
}
/**
+ * pci_get_rom_size - obtain the actual size of the ROM image
+ * @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(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)
+ 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);
+}
+
+/**
* 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
@@ -68,8 +111,6 @@ 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;
- void __iomem *image;
- int last_image;
/*
* IORESOURCE_ROM_SHADOW set on x86, x86_64 and IA64 supports legacy
@@ -117,33 +158,7 @@ void __iomem *pci_map_rom(struct pci_dev *pdev, size_t *size)
* size is much larger than the actual size of the ROM.
* True size is important if the ROM is going to be copied.
*/
- image = rom;
- do {
- void __iomem *pds;
- /* Standard PCI ROMs start out with these bytes 55 AA */
- if (readb(image) != 0x55)
- 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 */
- *size = min((size_t)(image - rom), *size);
-
+ *size = pci_get_rom_size(rom, *size);
return rom;
}