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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * PCI ROM access routines
4 *
5 * (C) Copyright 2004 Jon Smirl <jonsmirl@yahoo.com>
6 * (C) Copyright 2004 Silicon Graphics, Inc. Jesse Barnes <jbarnes@sgi.com>
7 */
8#include <linux/kernel.h>
9#include <linux/export.h>
10#include <linux/pci.h>
11#include <linux/slab.h>
12
13#include "pci.h"
14
15/**
16 * pci_enable_rom - enable ROM decoding for a PCI device
17 * @pdev: PCI device to enable
18 *
19 * Enable ROM decoding on @dev. This involves simply turning on the last
20 * bit of the PCI ROM BAR. Note that some cards may share address decoders
21 * between the ROM and other resources, so enabling it may disable access
22 * to MMIO registers or other card memory.
23 */
24int pci_enable_rom(struct pci_dev *pdev)
25{
26 struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
27 struct pci_bus_region region;
28 u32 rom_addr;
29
30 if (!res->flags)
31 return -1;
32
33 /* Nothing to enable if we're using a shadow copy in RAM */
34 if (res->flags & IORESOURCE_ROM_SHADOW)
35 return 0;
36
37 /*
38 * Ideally pci_update_resource() would update the ROM BAR address,
39 * and we would only set the enable bit here. But apparently some
40 * devices have buggy ROM BARs that read as zero when disabled.
41 */
42 pcibios_resource_to_bus(pdev->bus, ®ion, res);
43 pci_read_config_dword(pdev, pdev->rom_base_reg, &rom_addr);
44 rom_addr &= ~PCI_ROM_ADDRESS_MASK;
45 rom_addr |= region.start | PCI_ROM_ADDRESS_ENABLE;
46 pci_write_config_dword(pdev, pdev->rom_base_reg, rom_addr);
47 return 0;
48}
49EXPORT_SYMBOL_GPL(pci_enable_rom);
50
51/**
52 * pci_disable_rom - disable ROM decoding for a PCI device
53 * @pdev: PCI device to disable
54 *
55 * Disable ROM decoding on a PCI device by turning off the last bit in the
56 * ROM BAR.
57 */
58void pci_disable_rom(struct pci_dev *pdev)
59{
60 struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
61 u32 rom_addr;
62
63 if (res->flags & IORESOURCE_ROM_SHADOW)
64 return;
65
66 pci_read_config_dword(pdev, pdev->rom_base_reg, &rom_addr);
67 rom_addr &= ~PCI_ROM_ADDRESS_ENABLE;
68 pci_write_config_dword(pdev, pdev->rom_base_reg, rom_addr);
69}
70EXPORT_SYMBOL_GPL(pci_disable_rom);
71
72/**
73 * pci_get_rom_size - obtain the actual size of the ROM image
74 * @pdev: target PCI device
75 * @rom: kernel virtual pointer to image of ROM
76 * @size: size of PCI window
77 * return: size of actual ROM image
78 *
79 * Determine the actual length of the ROM image.
80 * The PCI window size could be much larger than the
81 * actual image size.
82 */
83static size_t pci_get_rom_size(struct pci_dev *pdev, void __iomem *rom,
84 size_t size)
85{
86 void __iomem *image;
87 int last_image;
88 unsigned int 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 pci_info(pdev, "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 pci_info(pdev, "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 if (!last_image) {
113 if (readw(image) != 0xAA55) {
114 pci_info(pdev, "No more image in the PCI ROM\n");
115 break;
116 }
117 }
118 } while (length && !last_image);
119
120 /* never return a size larger than the PCI resource window */
121 /* there are known ROMs that get the size wrong */
122 return min((size_t)(image - rom), size);
123}
124
125/**
126 * pci_map_rom - map a PCI ROM to kernel space
127 * @pdev: pointer to pci device struct
128 * @size: pointer to receive size of pci window over ROM
129 *
130 * Return: kernel virtual pointer to image of ROM
131 *
132 * Map a PCI ROM into kernel space. If ROM is boot video ROM,
133 * the shadow BIOS copy will be returned instead of the
134 * actual ROM.
135 */
136void __iomem *pci_map_rom(struct pci_dev *pdev, size_t *size)
137{
138 struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
139 loff_t start;
140 void __iomem *rom;
141
142 /* assign the ROM an address if it doesn't have one */
143 if (res->parent == NULL && pci_assign_resource(pdev, PCI_ROM_RESOURCE))
144 return NULL;
145
146 start = pci_resource_start(pdev, PCI_ROM_RESOURCE);
147 *size = pci_resource_len(pdev, PCI_ROM_RESOURCE);
148 if (*size == 0)
149 return NULL;
150
151 /* Enable ROM space decodes */
152 if (pci_enable_rom(pdev))
153 return NULL;
154
155 rom = ioremap(start, *size);
156 if (!rom)
157 goto err_ioremap;
158
159 /*
160 * Try to find the true size of the ROM since sometimes the PCI window
161 * size is much larger than the actual size of the ROM.
162 * True size is important if the ROM is going to be copied.
163 */
164 *size = pci_get_rom_size(pdev, rom, *size);
165 if (!*size)
166 goto invalid_rom;
167
168 return rom;
169
170invalid_rom:
171 iounmap(rom);
172err_ioremap:
173 /* restore enable if ioremap fails */
174 if (!(res->flags & IORESOURCE_ROM_ENABLE))
175 pci_disable_rom(pdev);
176 return NULL;
177}
178EXPORT_SYMBOL(pci_map_rom);
179
180/**
181 * pci_unmap_rom - unmap the ROM from kernel space
182 * @pdev: pointer to pci device struct
183 * @rom: virtual address of the previous mapping
184 *
185 * Remove a mapping of a previously mapped ROM
186 */
187void pci_unmap_rom(struct pci_dev *pdev, void __iomem *rom)
188{
189 struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
190
191 iounmap(rom);
192
193 /* Disable again before continuing */
194 if (!(res->flags & IORESOURCE_ROM_ENABLE))
195 pci_disable_rom(pdev);
196}
197EXPORT_SYMBOL(pci_unmap_rom);
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 */
25int 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 pcibios_resource_to_bus(pdev, ®ion, res);
35 pci_read_config_dword(pdev, pdev->rom_base_reg, &rom_addr);
36 rom_addr &= ~PCI_ROM_ADDRESS_MASK;
37 rom_addr |= region.start | PCI_ROM_ADDRESS_ENABLE;
38 pci_write_config_dword(pdev, pdev->rom_base_reg, rom_addr);
39 return 0;
40}
41
42/**
43 * pci_disable_rom - disable ROM decoding for a PCI device
44 * @pdev: PCI device to disable
45 *
46 * Disable ROM decoding on a PCI device by turning off the last bit in the
47 * ROM BAR.
48 */
49void pci_disable_rom(struct pci_dev *pdev)
50{
51 u32 rom_addr;
52 pci_read_config_dword(pdev, pdev->rom_base_reg, &rom_addr);
53 rom_addr &= ~PCI_ROM_ADDRESS_ENABLE;
54 pci_write_config_dword(pdev, pdev->rom_base_reg, rom_addr);
55}
56
57/**
58 * pci_get_rom_size - obtain the actual size of the ROM image
59 * @pdev: target PCI device
60 * @rom: kernel virtual pointer to image of ROM
61 * @size: size of PCI window
62 * return: size of actual ROM image
63 *
64 * Determine the actual length of the ROM image.
65 * The PCI window size could be much larger than the
66 * actual image size.
67 */
68size_t pci_get_rom_size(struct pci_dev *pdev, void __iomem *rom, size_t size)
69{
70 void __iomem *image;
71 int last_image;
72
73 image = rom;
74 do {
75 void __iomem *pds;
76 /* Standard PCI ROMs start out with these bytes 55 AA */
77 if (readb(image) != 0x55) {
78 dev_err(&pdev->dev, "Invalid ROM contents\n");
79 break;
80 }
81 if (readb(image + 1) != 0xAA)
82 break;
83 /* get the PCI data structure and check its signature */
84 pds = image + readw(image + 24);
85 if (readb(pds) != 'P')
86 break;
87 if (readb(pds + 1) != 'C')
88 break;
89 if (readb(pds + 2) != 'I')
90 break;
91 if (readb(pds + 3) != 'R')
92 break;
93 last_image = readb(pds + 21) & 0x80;
94 /* this length is reliable */
95 image += readw(pds + 16) * 512;
96 } while (!last_image);
97
98 /* never return a size larger than the PCI resource window */
99 /* there are known ROMs that get the size wrong */
100 return min((size_t)(image - rom), size);
101}
102
103/**
104 * pci_map_rom - map a PCI ROM to kernel space
105 * @pdev: pointer to pci device struct
106 * @size: pointer to receive size of pci window over ROM
107 *
108 * Return: kernel virtual pointer to image of ROM
109 *
110 * Map a PCI ROM into kernel space. If ROM is boot video ROM,
111 * the shadow BIOS copy will be returned instead of the
112 * actual ROM.
113 */
114void __iomem *pci_map_rom(struct pci_dev *pdev, size_t *size)
115{
116 struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
117 loff_t start;
118 void __iomem *rom;
119
120 /*
121 * IORESOURCE_ROM_SHADOW set on x86, x86_64 and IA64 supports legacy
122 * memory map if the VGA enable bit of the Bridge Control register is
123 * set for embedded VGA.
124 */
125 if (res->flags & IORESOURCE_ROM_SHADOW) {
126 /* primary video rom always starts here */
127 start = (loff_t)0xC0000;
128 *size = 0x20000; /* cover C000:0 through E000:0 */
129 } else {
130 if (res->flags &
131 (IORESOURCE_ROM_COPY | IORESOURCE_ROM_BIOS_COPY)) {
132 *size = pci_resource_len(pdev, PCI_ROM_RESOURCE);
133 return (void __iomem *)(unsigned long)
134 pci_resource_start(pdev, PCI_ROM_RESOURCE);
135 } else {
136 /* assign the ROM an address if it doesn't have one */
137 if (res->parent == NULL &&
138 pci_assign_resource(pdev,PCI_ROM_RESOURCE))
139 return NULL;
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 }
150
151 rom = ioremap(start, *size);
152 if (!rom) {
153 /* restore enable if ioremap fails */
154 if (!(res->flags & (IORESOURCE_ROM_ENABLE |
155 IORESOURCE_ROM_SHADOW |
156 IORESOURCE_ROM_COPY)))
157 pci_disable_rom(pdev);
158 return NULL;
159 }
160
161 /*
162 * Try to find the true size of the ROM since sometimes the PCI window
163 * size is much larger than the actual size of the ROM.
164 * True size is important if the ROM is going to be copied.
165 */
166 *size = pci_get_rom_size(pdev, rom, *size);
167 return rom;
168}
169
170#if 0
171/**
172 * pci_map_rom_copy - map a PCI ROM to kernel space, create a copy
173 * @pdev: pointer to pci device struct
174 * @size: pointer to receive size of pci window over ROM
175 *
176 * Return: kernel virtual pointer to image of ROM
177 *
178 * Map a PCI ROM into kernel space. If ROM is boot video ROM,
179 * the shadow BIOS copy will be returned instead of the
180 * actual ROM.
181 */
182void __iomem *pci_map_rom_copy(struct pci_dev *pdev, size_t *size)
183{
184 struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
185 void __iomem *rom;
186
187 rom = pci_map_rom(pdev, size);
188 if (!rom)
189 return NULL;
190
191 if (res->flags & (IORESOURCE_ROM_COPY | IORESOURCE_ROM_SHADOW |
192 IORESOURCE_ROM_BIOS_COPY))
193 return rom;
194
195 res->start = (unsigned long)kmalloc(*size, GFP_KERNEL);
196 if (!res->start)
197 return rom;
198
199 res->end = res->start + *size;
200 memcpy_fromio((void*)(unsigned long)res->start, rom, *size);
201 pci_unmap_rom(pdev, rom);
202 res->flags |= IORESOURCE_ROM_COPY;
203
204 return (void __iomem *)(unsigned long)res->start;
205}
206#endif /* 0 */
207
208/**
209 * pci_unmap_rom - unmap the ROM from kernel space
210 * @pdev: pointer to pci device struct
211 * @rom: virtual address of the previous mapping
212 *
213 * Remove a mapping of a previously mapped ROM
214 */
215void pci_unmap_rom(struct pci_dev *pdev, void __iomem *rom)
216{
217 struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
218
219 if (res->flags & (IORESOURCE_ROM_COPY | IORESOURCE_ROM_BIOS_COPY))
220 return;
221
222 iounmap(rom);
223
224 /* Disable again before continuing, leave enabled if pci=rom */
225 if (!(res->flags & (IORESOURCE_ROM_ENABLE | IORESOURCE_ROM_SHADOW)))
226 pci_disable_rom(pdev);
227}
228
229#if 0
230/**
231 * pci_remove_rom - disable the ROM and remove its sysfs attribute
232 * @pdev: pointer to pci device struct
233 *
234 * Remove the rom file in sysfs and disable ROM decoding.
235 */
236void pci_remove_rom(struct pci_dev *pdev)
237{
238 struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
239
240 if (pci_resource_len(pdev, PCI_ROM_RESOURCE))
241 sysfs_remove_bin_file(&pdev->dev.kobj, pdev->rom_attr);
242 if (!(res->flags & (IORESOURCE_ROM_ENABLE |
243 IORESOURCE_ROM_SHADOW |
244 IORESOURCE_ROM_BIOS_COPY |
245 IORESOURCE_ROM_COPY)))
246 pci_disable_rom(pdev);
247}
248#endif /* 0 */
249
250/**
251 * pci_cleanup_rom - free the ROM copy created by pci_map_rom_copy
252 * @pdev: pointer to pci device struct
253 *
254 * Free the copied ROM if we allocated one.
255 */
256void pci_cleanup_rom(struct pci_dev *pdev)
257{
258 struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
259 if (res->flags & IORESOURCE_ROM_COPY) {
260 kfree((void*)(unsigned long)res->start);
261 res->flags &= ~IORESOURCE_ROM_COPY;
262 res->start = 0;
263 res->end = 0;
264 }
265}
266
267EXPORT_SYMBOL(pci_map_rom);
268EXPORT_SYMBOL(pci_unmap_rom);
269EXPORT_SYMBOL_GPL(pci_enable_rom);
270EXPORT_SYMBOL_GPL(pci_disable_rom);