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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  */
pci_enable_rom(struct pci_dev * pdev)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 	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  */
pci_disable_rom(struct pci_dev * pdev)49 void 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  */
pci_get_rom_size(struct pci_dev * pdev,void __iomem * rom,size_t size)68 size_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  */
pci_map_rom(struct pci_dev * pdev,size_t * size)114 void __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  */
182 void __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  */
pci_unmap_rom(struct pci_dev * pdev,void __iomem * rom)215 void 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  */
236 void 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  */
pci_cleanup_rom(struct pci_dev * pdev)256 void 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 
267 EXPORT_SYMBOL(pci_map_rom);
268 EXPORT_SYMBOL(pci_unmap_rom);
269 EXPORT_SYMBOL_GPL(pci_enable_rom);
270 EXPORT_SYMBOL_GPL(pci_disable_rom);
271