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1 | /* | |
2 | * drivers/pci/rom.c | |
3 | * | |
4 | * (C) Copyright 2004 Jon Smirl <jonsmirl@yahoo.com> | |
5 | * (C) Copyright 2004 Silicon Graphics, Inc. Jesse Barnes <jbarnes@sgi.com> | |
6 | * | |
7 | * PCI ROM access routines | |
8 | */ | |
9 | #include <linux/kernel.h> | |
10 | #include <linux/export.h> | |
11 | #include <linux/pci.h> | |
12 | #include <linux/slab.h> | |
13 | ||
14 | #include "pci.h" | |
15 | ||
16 | /** | |
17 | * pci_enable_rom - enable ROM decoding for a PCI device | |
18 | * @pdev: PCI device to enable | |
19 | * | |
20 | * Enable ROM decoding on @dev. This involves simply turning on the last | |
21 | * bit of the PCI ROM BAR. Note that some cards may share address decoders | |
22 | * between the ROM and other resources, so enabling it may disable access | |
23 | * to MMIO registers or other card memory. | |
24 | */ | |
25 | int pci_enable_rom(struct pci_dev *pdev) | |
26 | { | |
27 | struct resource *res = &pdev->resource[PCI_ROM_RESOURCE]; | |
28 | struct pci_bus_region region; | |
29 | u32 rom_addr; | |
30 | ||
31 | if (!res->flags) | |
32 | return -1; | |
33 | ||
34 | /* Nothing to enable if we're using a shadow copy in RAM */ | |
35 | if (res->flags & IORESOURCE_ROM_SHADOW) | |
36 | return 0; | |
37 | ||
38 | /* | |
39 | * Ideally pci_update_resource() would update the ROM BAR address, | |
40 | * and we would only set the enable bit here. But apparently some | |
41 | * devices have buggy ROM BARs that read as zero when disabled. | |
42 | */ | |
43 | pcibios_resource_to_bus(pdev->bus, ®ion, res); | |
44 | pci_read_config_dword(pdev, pdev->rom_base_reg, &rom_addr); | |
45 | rom_addr &= ~PCI_ROM_ADDRESS_MASK; | |
46 | rom_addr |= region.start | PCI_ROM_ADDRESS_ENABLE; | |
47 | pci_write_config_dword(pdev, pdev->rom_base_reg, rom_addr); | |
48 | return 0; | |
49 | } | |
50 | EXPORT_SYMBOL_GPL(pci_enable_rom); | |
51 | ||
52 | /** | |
53 | * pci_disable_rom - disable ROM decoding for a PCI device | |
54 | * @pdev: PCI device to disable | |
55 | * | |
56 | * Disable ROM decoding on a PCI device by turning off the last bit in the | |
57 | * ROM BAR. | |
58 | */ | |
59 | void pci_disable_rom(struct pci_dev *pdev) | |
60 | { | |
61 | struct resource *res = &pdev->resource[PCI_ROM_RESOURCE]; | |
62 | u32 rom_addr; | |
63 | ||
64 | if (res->flags & IORESOURCE_ROM_SHADOW) | |
65 | return; | |
66 | ||
67 | pci_read_config_dword(pdev, pdev->rom_base_reg, &rom_addr); | |
68 | rom_addr &= ~PCI_ROM_ADDRESS_ENABLE; | |
69 | pci_write_config_dword(pdev, pdev->rom_base_reg, rom_addr); | |
70 | } | |
71 | EXPORT_SYMBOL_GPL(pci_disable_rom); | |
72 | ||
73 | /** | |
74 | * pci_get_rom_size - obtain the actual size of the ROM image | |
75 | * @pdev: target PCI device | |
76 | * @rom: kernel virtual pointer to image of ROM | |
77 | * @size: size of PCI window | |
78 | * return: size of actual ROM image | |
79 | * | |
80 | * Determine the actual length of the ROM image. | |
81 | * The PCI window size could be much larger than the | |
82 | * actual image size. | |
83 | */ | |
84 | size_t pci_get_rom_size(struct pci_dev *pdev, void __iomem *rom, size_t size) | |
85 | { | |
86 | void __iomem *image; | |
87 | int last_image; | |
88 | unsigned length; | |
89 | ||
90 | image = rom; | |
91 | do { | |
92 | void __iomem *pds; | |
93 | /* Standard PCI ROMs start out with these bytes 55 AA */ | |
94 | if (readw(image) != 0xAA55) { | |
95 | dev_err(&pdev->dev, "Invalid PCI ROM header signature: expecting 0xaa55, got %#06x\n", | |
96 | readw(image)); | |
97 | break; | |
98 | } | |
99 | /* get the PCI data structure and check its "PCIR" signature */ | |
100 | pds = image + readw(image + 24); | |
101 | if (readl(pds) != 0x52494350) { | |
102 | dev_err(&pdev->dev, "Invalid PCI ROM data signature: expecting 0x52494350, got %#010x\n", | |
103 | readl(pds)); | |
104 | break; | |
105 | } | |
106 | last_image = readb(pds + 21) & 0x80; | |
107 | length = readw(pds + 16); | |
108 | image += length * 512; | |
109 | /* Avoid iterating through memory outside the resource window */ | |
110 | if (image > rom + size) | |
111 | break; | |
112 | } while (length && !last_image); | |
113 | ||
114 | /* never return a size larger than the PCI resource window */ | |
115 | /* there are known ROMs that get the size wrong */ | |
116 | return min((size_t)(image - rom), size); | |
117 | } | |
118 | ||
119 | /** | |
120 | * pci_map_rom - map a PCI ROM to kernel space | |
121 | * @pdev: pointer to pci device struct | |
122 | * @size: pointer to receive size of pci window over ROM | |
123 | * | |
124 | * Return: kernel virtual pointer to image of ROM | |
125 | * | |
126 | * Map a PCI ROM into kernel space. If ROM is boot video ROM, | |
127 | * the shadow BIOS copy will be returned instead of the | |
128 | * actual ROM. | |
129 | */ | |
130 | void __iomem *pci_map_rom(struct pci_dev *pdev, size_t *size) | |
131 | { | |
132 | struct resource *res = &pdev->resource[PCI_ROM_RESOURCE]; | |
133 | loff_t start; | |
134 | void __iomem *rom; | |
135 | ||
136 | /* assign the ROM an address if it doesn't have one */ | |
137 | if (res->parent == NULL && pci_assign_resource(pdev, PCI_ROM_RESOURCE)) | |
138 | return NULL; | |
139 | ||
140 | start = pci_resource_start(pdev, PCI_ROM_RESOURCE); | |
141 | *size = pci_resource_len(pdev, PCI_ROM_RESOURCE); | |
142 | if (*size == 0) | |
143 | return NULL; | |
144 | ||
145 | /* Enable ROM space decodes */ | |
146 | if (pci_enable_rom(pdev)) | |
147 | return NULL; | |
148 | ||
149 | rom = ioremap(start, *size); | |
150 | if (!rom) | |
151 | goto err_ioremap; | |
152 | ||
153 | /* | |
154 | * Try to find the true size of the ROM since sometimes the PCI window | |
155 | * size is much larger than the actual size of the ROM. | |
156 | * True size is important if the ROM is going to be copied. | |
157 | */ | |
158 | *size = pci_get_rom_size(pdev, rom, *size); | |
159 | if (!*size) | |
160 | goto invalid_rom; | |
161 | ||
162 | return rom; | |
163 | ||
164 | invalid_rom: | |
165 | iounmap(rom); | |
166 | err_ioremap: | |
167 | /* restore enable if ioremap fails */ | |
168 | if (!(res->flags & IORESOURCE_ROM_ENABLE)) | |
169 | pci_disable_rom(pdev); | |
170 | return NULL; | |
171 | } | |
172 | EXPORT_SYMBOL(pci_map_rom); | |
173 | ||
174 | /** | |
175 | * pci_unmap_rom - unmap the ROM from kernel space | |
176 | * @pdev: pointer to pci device struct | |
177 | * @rom: virtual address of the previous mapping | |
178 | * | |
179 | * Remove a mapping of a previously mapped ROM | |
180 | */ | |
181 | void pci_unmap_rom(struct pci_dev *pdev, void __iomem *rom) | |
182 | { | |
183 | struct resource *res = &pdev->resource[PCI_ROM_RESOURCE]; | |
184 | ||
185 | iounmap(rom); | |
186 | ||
187 | /* Disable again before continuing */ | |
188 | if (!(res->flags & IORESOURCE_ROM_ENABLE)) | |
189 | pci_disable_rom(pdev); | |
190 | } | |
191 | EXPORT_SYMBOL(pci_unmap_rom); | |
192 | ||
193 | /** | |
194 | * pci_platform_rom - provides a pointer to any ROM image provided by the | |
195 | * platform | |
196 | * @pdev: pointer to pci device struct | |
197 | * @size: pointer to receive size of pci window over ROM | |
198 | */ | |
199 | void __iomem *pci_platform_rom(struct pci_dev *pdev, size_t *size) | |
200 | { | |
201 | if (pdev->rom && pdev->romlen) { | |
202 | *size = pdev->romlen; | |
203 | return phys_to_virt((phys_addr_t)pdev->rom); | |
204 | } | |
205 | ||
206 | return NULL; | |
207 | } | |
208 | EXPORT_SYMBOL(pci_platform_rom); |