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-rw-r--r--drivers/pci/rom.c197
1 files changed, 197 insertions, 0 deletions
diff --git a/drivers/pci/rom.c b/drivers/pci/rom.c
new file mode 100644
index 000000000..e18d3a438
--- /dev/null
+++ b/drivers/pci/rom.c
@@ -0,0 +1,197 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * PCI ROM access routines
+ *
+ * (C) Copyright 2004 Jon Smirl <jonsmirl@yahoo.com>
+ * (C) Copyright 2004 Silicon Graphics, Inc. Jesse Barnes <jbarnes@sgi.com>
+ */
+#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;
+
+ /* Nothing to enable if we're using a shadow copy in RAM */
+ if (res->flags & IORESOURCE_ROM_SHADOW)
+ return 0;
+
+ /*
+ * Ideally pci_update_resource() would update the ROM BAR address,
+ * and we would only set the enable bit here. But apparently some
+ * devices have buggy ROM BARs that read as zero when disabled.
+ */
+ pcibios_resource_to_bus(pdev->bus, &region, 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;
+}
+EXPORT_SYMBOL_GPL(pci_enable_rom);
+
+/**
+ * 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)
+{
+ struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
+ u32 rom_addr;
+
+ if (res->flags & IORESOURCE_ROM_SHADOW)
+ return;
+
+ 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);
+}
+EXPORT_SYMBOL_GPL(pci_disable_rom);
+
+/**
+ * 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.
+ */
+static size_t pci_get_rom_size(struct pci_dev *pdev, void __iomem *rom,
+ size_t size)
+{
+ void __iomem *image;
+ int last_image;
+ unsigned int length;
+
+ image = rom;
+ do {
+ void __iomem *pds;
+ /* Standard PCI ROMs start out with these bytes 55 AA */
+ if (readw(image) != 0xAA55) {
+ pci_info(pdev, "Invalid PCI ROM header signature: expecting 0xaa55, got %#06x\n",
+ readw(image));
+ break;
+ }
+ /* get the PCI data structure and check its "PCIR" signature */
+ pds = image + readw(image + 24);
+ if (readl(pds) != 0x52494350) {
+ pci_info(pdev, "Invalid PCI ROM data signature: expecting 0x52494350, got %#010x\n",
+ readl(pds));
+ break;
+ }
+ last_image = readb(pds + 21) & 0x80;
+ length = readw(pds + 16);
+ image += length * 512;
+ /* Avoid iterating through memory outside the resource window */
+ if (image >= rom + size)
+ break;
+ if (!last_image) {
+ if (readw(image) != 0xAA55) {
+ pci_info(pdev, "No more image in the PCI ROM\n");
+ break;
+ }
+ }
+ } while (length && !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
+ *
+ * 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;
+ void __iomem *rom;
+
+ /* assign the ROM an address if it doesn't have one */
+ if (res->parent == NULL && pci_assign_resource(pdev, PCI_ROM_RESOURCE))
+ return NULL;
+
+ start = pci_resource_start(pdev, PCI_ROM_RESOURCE);
+ *size = pci_resource_len(pdev, PCI_ROM_RESOURCE);
+ if (*size == 0)
+ return NULL;
+
+ /* Enable ROM space decodes */
+ if (pci_enable_rom(pdev))
+ return NULL;
+
+ rom = ioremap(start, *size);
+ if (!rom)
+ goto err_ioremap;
+
+ /*
+ * 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);
+ if (!*size)
+ goto invalid_rom;
+
+ return rom;
+
+invalid_rom:
+ iounmap(rom);
+err_ioremap:
+ /* restore enable if ioremap fails */
+ if (!(res->flags & IORESOURCE_ROM_ENABLE))
+ pci_disable_rom(pdev);
+ return NULL;
+}
+EXPORT_SYMBOL(pci_map_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];
+
+ iounmap(rom);
+
+ /* Disable again before continuing */
+ if (!(res->flags & IORESOURCE_ROM_ENABLE))
+ pci_disable_rom(pdev);
+}
+EXPORT_SYMBOL(pci_unmap_rom);