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/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 */
pci_enable_rom(struct pci_dev * pdev)24 int 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 pcibios_resource_to_bus(pdev, ®ion, res);
34 pci_read_config_dword(pdev, pdev->rom_base_reg, &rom_addr);
35 rom_addr &= ~PCI_ROM_ADDRESS_MASK;
36 rom_addr |= region.start | PCI_ROM_ADDRESS_ENABLE;
37 pci_write_config_dword(pdev, pdev->rom_base_reg, rom_addr);
38 return 0;
39 }
40
41 /**
42 * pci_disable_rom - disable ROM decoding for a PCI device
43 * @pdev: PCI device to disable
44 *
45 * Disable ROM decoding on a PCI device by turning off the last bit in the
46 * ROM BAR.
47 */
pci_disable_rom(struct pci_dev * pdev)48 void pci_disable_rom(struct pci_dev *pdev)
49 {
50 u32 rom_addr;
51 pci_read_config_dword(pdev, pdev->rom_base_reg, &rom_addr);
52 rom_addr &= ~PCI_ROM_ADDRESS_ENABLE;
53 pci_write_config_dword(pdev, pdev->rom_base_reg, rom_addr);
54 }
55
56 /**
57 * pci_get_rom_size - obtain the actual size of the ROM image
58 * @pdev: target PCI device
59 * @rom: kernel virtual pointer to image of ROM
60 * @size: size of PCI window
61 * return: size of actual ROM image
62 *
63 * Determine the actual length of the ROM image.
64 * The PCI window size could be much larger than the
65 * actual image size.
66 */
pci_get_rom_size(struct pci_dev * pdev,void __iomem * rom,size_t size)67 size_t pci_get_rom_size(struct pci_dev *pdev, void __iomem *rom, size_t size)
68 {
69 void __iomem *image;
70 int last_image;
71
72 image = rom;
73 do {
74 void __iomem *pds;
75 /* Standard PCI ROMs start out with these bytes 55 AA */
76 if (readb(image) != 0x55) {
77 dev_err(&pdev->dev, "Invalid ROM contents\n");
78 break;
79 }
80 if (readb(image + 1) != 0xAA)
81 break;
82 /* get the PCI data structure and check its signature */
83 pds = image + readw(image + 24);
84 if (readb(pds) != 'P')
85 break;
86 if (readb(pds + 1) != 'C')
87 break;
88 if (readb(pds + 2) != 'I')
89 break;
90 if (readb(pds + 3) != 'R')
91 break;
92 last_image = readb(pds + 21) & 0x80;
93 /* this length is reliable */
94 image += readw(pds + 16) * 512;
95 } while (!last_image);
96
97 /* never return a size larger than the PCI resource window */
98 /* there are known ROMs that get the size wrong */
99 return min((size_t)(image - rom), size);
100 }
101
102 /**
103 * pci_map_rom - map a PCI ROM to kernel space
104 * @pdev: pointer to pci device struct
105 * @size: pointer to receive size of pci window over ROM
106 *
107 * Return: kernel virtual pointer to image of ROM
108 *
109 * Map a PCI ROM into kernel space. If ROM is boot video ROM,
110 * the shadow BIOS copy will be returned instead of the
111 * actual ROM.
112 */
pci_map_rom(struct pci_dev * pdev,size_t * size)113 void __iomem *pci_map_rom(struct pci_dev *pdev, size_t *size)
114 {
115 struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
116 loff_t start;
117 void __iomem *rom;
118
119 /*
120 * IORESOURCE_ROM_SHADOW set on x86, x86_64 and IA64 supports legacy
121 * memory map if the VGA enable bit of the Bridge Control register is
122 * set for embedded VGA.
123 */
124 if (res->flags & IORESOURCE_ROM_SHADOW) {
125 /* primary video rom always starts here */
126 start = (loff_t)0xC0000;
127 *size = 0x20000; /* cover C000:0 through E000:0 */
128 } else {
129 if (res->flags &
130 (IORESOURCE_ROM_COPY | IORESOURCE_ROM_BIOS_COPY)) {
131 *size = pci_resource_len(pdev, PCI_ROM_RESOURCE);
132 return (void __iomem *)(unsigned long)
133 pci_resource_start(pdev, PCI_ROM_RESOURCE);
134 } else {
135 /* assign the ROM an address if it doesn't have one */
136 if (res->parent == NULL &&
137 pci_assign_resource(pdev,PCI_ROM_RESOURCE))
138 return NULL;
139 start = pci_resource_start(pdev, PCI_ROM_RESOURCE);
140 *size = pci_resource_len(pdev, PCI_ROM_RESOURCE);
141 if (*size == 0)
142 return NULL;
143
144 /* Enable ROM space decodes */
145 if (pci_enable_rom(pdev))
146 return NULL;
147 }
148 }
149
150 rom = ioremap(start, *size);
151 if (!rom) {
152 /* restore enable if ioremap fails */
153 if (!(res->flags & (IORESOURCE_ROM_ENABLE |
154 IORESOURCE_ROM_SHADOW |
155 IORESOURCE_ROM_COPY)))
156 pci_disable_rom(pdev);
157 return NULL;
158 }
159
160 /*
161 * Try to find the true size of the ROM since sometimes the PCI window
162 * size is much larger than the actual size of the ROM.
163 * True size is important if the ROM is going to be copied.
164 */
165 *size = pci_get_rom_size(pdev, rom, *size);
166 return rom;
167 }
168
169 #if 0
170 /**
171 * pci_map_rom_copy - map a PCI ROM to kernel space, create a copy
172 * @pdev: pointer to pci device struct
173 * @size: pointer to receive size of pci window over ROM
174 *
175 * Return: kernel virtual pointer to image of ROM
176 *
177 * Map a PCI ROM into kernel space. If ROM is boot video ROM,
178 * the shadow BIOS copy will be returned instead of the
179 * actual ROM.
180 */
181 void __iomem *pci_map_rom_copy(struct pci_dev *pdev, size_t *size)
182 {
183 struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
184 void __iomem *rom;
185
186 rom = pci_map_rom(pdev, size);
187 if (!rom)
188 return NULL;
189
190 if (res->flags & (IORESOURCE_ROM_COPY | IORESOURCE_ROM_SHADOW |
191 IORESOURCE_ROM_BIOS_COPY))
192 return rom;
193
194 res->start = (unsigned long)kmalloc(*size, GFP_KERNEL);
195 if (!res->start)
196 return rom;
197
198 res->end = res->start + *size;
199 memcpy_fromio((void*)(unsigned long)res->start, rom, *size);
200 pci_unmap_rom(pdev, rom);
201 res->flags |= IORESOURCE_ROM_COPY;
202
203 return (void __iomem *)(unsigned long)res->start;
204 }
205 #endif /* 0 */
206
207 /**
208 * pci_unmap_rom - unmap the ROM from kernel space
209 * @pdev: pointer to pci device struct
210 * @rom: virtual address of the previous mapping
211 *
212 * Remove a mapping of a previously mapped ROM
213 */
pci_unmap_rom(struct pci_dev * pdev,void __iomem * rom)214 void pci_unmap_rom(struct pci_dev *pdev, void __iomem *rom)
215 {
216 struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
217
218 if (res->flags & (IORESOURCE_ROM_COPY | IORESOURCE_ROM_BIOS_COPY))
219 return;
220
221 iounmap(rom);
222
223 /* Disable again before continuing, leave enabled if pci=rom */
224 if (!(res->flags & (IORESOURCE_ROM_ENABLE | IORESOURCE_ROM_SHADOW)))
225 pci_disable_rom(pdev);
226 }
227
228 #if 0
229 /**
230 * pci_remove_rom - disable the ROM and remove its sysfs attribute
231 * @pdev: pointer to pci device struct
232 *
233 * Remove the rom file in sysfs and disable ROM decoding.
234 */
235 void pci_remove_rom(struct pci_dev *pdev)
236 {
237 struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
238
239 if (pci_resource_len(pdev, PCI_ROM_RESOURCE))
240 sysfs_remove_bin_file(&pdev->dev.kobj, pdev->rom_attr);
241 if (!(res->flags & (IORESOURCE_ROM_ENABLE |
242 IORESOURCE_ROM_SHADOW |
243 IORESOURCE_ROM_BIOS_COPY |
244 IORESOURCE_ROM_COPY)))
245 pci_disable_rom(pdev);
246 }
247 #endif /* 0 */
248
249 /**
250 * pci_cleanup_rom - free the ROM copy created by pci_map_rom_copy
251 * @pdev: pointer to pci device struct
252 *
253 * Free the copied ROM if we allocated one.
254 */
pci_cleanup_rom(struct pci_dev * pdev)255 void pci_cleanup_rom(struct pci_dev *pdev)
256 {
257 struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
258 if (res->flags & IORESOURCE_ROM_COPY) {
259 kfree((void*)(unsigned long)res->start);
260 res->flags &= ~IORESOURCE_ROM_COPY;
261 res->start = 0;
262 res->end = 0;
263 }
264 }
265
266 EXPORT_SYMBOL(pci_map_rom);
267 EXPORT_SYMBOL(pci_unmap_rom);
268 EXPORT_SYMBOL_GPL(pci_enable_rom);
269 EXPORT_SYMBOL_GPL(pci_disable_rom);
270