Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

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..8fc9a4e91
--- /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 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);