rom.c 5.6 KB
Newer Older
L
Linus Torvalds 已提交
1 2 3 4 5 6 7 8 9
/*
 * 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>
10
#include <linux/export.h>
L
Linus Torvalds 已提交
11
#include <linux/pci.h>
T
Tim Schmielau 已提交
12
#include <linux/slab.h>
L
Linus Torvalds 已提交
13 14 15 16 17

#include "pci.h"

/**
 * pci_enable_rom - enable ROM decoding for a PCI device
18
 * @pdev: PCI device to enable
L
Linus Torvalds 已提交
19 20 21 22 23 24
 *
 * 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.
 */
A
Alan Cox 已提交
25
int pci_enable_rom(struct pci_dev *pdev)
L
Linus Torvalds 已提交
26
{
27
	struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
28
	struct pci_bus_region region;
L
Linus Torvalds 已提交
29 30
	u32 rom_addr;

31 32 33
	if (!res->flags)
		return -1;

34 35 36 37
	/* Nothing to enable if we're using a shadow copy in RAM */
	if (res->flags & IORESOURCE_ROM_SHADOW)
		return 0;

38 39 40 41 42
	/*
	 * 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.
	 */
43
	pcibios_resource_to_bus(pdev->bus, &region, res);
L
Linus Torvalds 已提交
44
	pci_read_config_dword(pdev, pdev->rom_base_reg, &rom_addr);
45 46
	rom_addr &= ~PCI_ROM_ADDRESS_MASK;
	rom_addr |= region.start | PCI_ROM_ADDRESS_ENABLE;
L
Linus Torvalds 已提交
47
	pci_write_config_dword(pdev, pdev->rom_base_reg, rom_addr);
48
	return 0;
L
Linus Torvalds 已提交
49
}
50
EXPORT_SYMBOL_GPL(pci_enable_rom);
L
Linus Torvalds 已提交
51 52 53

/**
 * pci_disable_rom - disable ROM decoding for a PCI device
54
 * @pdev: PCI device to disable
L
Linus Torvalds 已提交
55 56 57 58
 *
 * Disable ROM decoding on a PCI device by turning off the last bit in the
 * ROM BAR.
 */
A
Alan Cox 已提交
59
void pci_disable_rom(struct pci_dev *pdev)
L
Linus Torvalds 已提交
60
{
61
	struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
L
Linus Torvalds 已提交
62
	u32 rom_addr;
63 64 65 66

	if (res->flags & IORESOURCE_ROM_SHADOW)
		return;

L
Linus Torvalds 已提交
67 68 69 70
	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);
}
71
EXPORT_SYMBOL_GPL(pci_disable_rom);
L
Linus Torvalds 已提交
72

73 74
/**
 * pci_get_rom_size - obtain the actual size of the ROM image
R
Randy Dunlap 已提交
75
 * @pdev: target PCI device
76 77 78 79 80 81 82 83
 * @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.
 */
84
size_t pci_get_rom_size(struct pci_dev *pdev, void __iomem *rom, size_t size)
85 86 87
{
	void __iomem *image;
	int last_image;
88
	unsigned length;
89 90 91 92 93

	image = rom;
	do {
		void __iomem *pds;
		/* Standard PCI ROMs start out with these bytes 55 AA */
94 95 96
		if (readw(image) != 0xAA55) {
			dev_err(&pdev->dev, "Invalid PCI ROM header signature: expecting 0xaa55, got %#06x\n",
				readw(image));
97
			break;
98
		}
99
		/* get the PCI data structure and check its "PCIR" signature */
100
		pds = image + readw(image + 24);
101 102 103
		if (readl(pds) != 0x52494350) {
			dev_err(&pdev->dev, "Invalid PCI ROM data signature: expecting 0x52494350, got %#010x\n",
				readl(pds));
104
			break;
105
		}
106
		last_image = readb(pds + 21) & 0x80;
107 108
		length = readw(pds + 16);
		image += length * 512;
109 110 111
		/* Avoid iterating through memory outside the resource window */
		if (image > rom + size)
			break;
112
	} while (length && !last_image);
113 114 115 116 117 118

	/* 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);
}

L
Linus Torvalds 已提交
119 120
/**
 * pci_map_rom - map a PCI ROM to kernel space
121
 * @pdev: pointer to pci device struct
L
Linus Torvalds 已提交
122
 * @size: pointer to receive size of pci window over ROM
123 124
 *
 * Return: kernel virtual pointer to image of ROM
L
Linus Torvalds 已提交
125 126 127 128 129 130 131 132
 *
 * 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];
133
	loff_t start;
L
Linus Torvalds 已提交
134 135
	void __iomem *rom;

136 137 138 139 140 141 142 143 144 145 146 147
	/* 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;
148

L
Linus Torvalds 已提交
149
	rom = ioremap(start, *size);
C
Changbin Du 已提交
150 151
	if (!rom)
		goto err_ioremap;
L
Linus Torvalds 已提交
152 153 154 155 156 157

	/*
	 * 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.
	 */
158
	*size = pci_get_rom_size(pdev, rom, *size);
159 160 161
	if (!*size)
		goto invalid_rom;

L
Linus Torvalds 已提交
162
	return rom;
C
Changbin Du 已提交
163

164 165
invalid_rom:
	iounmap(rom);
C
Changbin Du 已提交
166 167 168 169 170
err_ioremap:
	/* restore enable if ioremap fails */
	if (!(res->flags & IORESOURCE_ROM_ENABLE))
		pci_disable_rom(pdev);
	return NULL;
L
Linus Torvalds 已提交
171
}
172
EXPORT_SYMBOL(pci_map_rom);
L
Linus Torvalds 已提交
173 174 175

/**
 * pci_unmap_rom - unmap the ROM from kernel space
176
 * @pdev: pointer to pci device struct
L
Linus Torvalds 已提交
177 178 179 180 181 182 183 184
 * @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];

185
	iounmap(rom);
L
Linus Torvalds 已提交
186

187 188
	/* Disable again before continuing */
	if (!(res->flags & IORESOURCE_ROM_ENABLE))
L
Linus Torvalds 已提交
189 190
		pci_disable_rom(pdev);
}
191
EXPORT_SYMBOL(pci_unmap_rom);
L
Linus Torvalds 已提交
192

193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208
/**
 * pci_platform_rom - provides a pointer to any ROM image provided by the
 * platform
 * @pdev: pointer to pci device struct
 * @size: pointer to receive size of pci window over ROM
 */
void __iomem *pci_platform_rom(struct pci_dev *pdev, size_t *size)
{
	if (pdev->rom && pdev->romlen) {
		*size = pdev->romlen;
		return phys_to_virt((phys_addr_t)pdev->rom);
	}

	return NULL;
}
EXPORT_SYMBOL(pci_platform_rom);