Root/drivers/pci/rom.c

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, &region, 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);
271

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