xref: /openbmc/linux/arch/x86/kernel/probe_roms.c (revision 81d67439)
1 #include <linux/sched.h>
2 #include <linux/mm.h>
3 #include <linux/uaccess.h>
4 #include <linux/mmzone.h>
5 #include <linux/ioport.h>
6 #include <linux/seq_file.h>
7 #include <linux/console.h>
8 #include <linux/init.h>
9 #include <linux/edd.h>
10 #include <linux/dmi.h>
11 #include <linux/pfn.h>
12 #include <linux/pci.h>
13 #include <asm/pci-direct.h>
14 
15 
16 #include <asm/e820.h>
17 #include <asm/mmzone.h>
18 #include <asm/setup.h>
19 #include <asm/sections.h>
20 #include <asm/io.h>
21 #include <asm/setup_arch.h>
22 
23 static struct resource system_rom_resource = {
24 	.name	= "System ROM",
25 	.start	= 0xf0000,
26 	.end	= 0xfffff,
27 	.flags	= IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
28 };
29 
30 static struct resource extension_rom_resource = {
31 	.name	= "Extension ROM",
32 	.start	= 0xe0000,
33 	.end	= 0xeffff,
34 	.flags	= IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
35 };
36 
37 static struct resource adapter_rom_resources[] = { {
38 	.name 	= "Adapter ROM",
39 	.start	= 0xc8000,
40 	.end	= 0,
41 	.flags	= IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
42 }, {
43 	.name 	= "Adapter ROM",
44 	.start	= 0,
45 	.end	= 0,
46 	.flags	= IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
47 }, {
48 	.name 	= "Adapter ROM",
49 	.start	= 0,
50 	.end	= 0,
51 	.flags	= IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
52 }, {
53 	.name 	= "Adapter ROM",
54 	.start	= 0,
55 	.end	= 0,
56 	.flags	= IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
57 }, {
58 	.name 	= "Adapter ROM",
59 	.start	= 0,
60 	.end	= 0,
61 	.flags	= IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
62 }, {
63 	.name 	= "Adapter ROM",
64 	.start	= 0,
65 	.end	= 0,
66 	.flags	= IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
67 } };
68 
69 static struct resource video_rom_resource = {
70 	.name 	= "Video ROM",
71 	.start	= 0xc0000,
72 	.end	= 0xc7fff,
73 	.flags	= IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
74 };
75 
76 /* does this oprom support the given pci device, or any of the devices
77  * that the driver supports?
78  */
79 static bool match_id(struct pci_dev *pdev, unsigned short vendor, unsigned short device)
80 {
81 	struct pci_driver *drv = pdev->driver;
82 	const struct pci_device_id *id;
83 
84 	if (pdev->vendor == vendor && pdev->device == device)
85 		return true;
86 
87 	for (id = drv ? drv->id_table : NULL; id && id->vendor; id++)
88 		if (id->vendor == vendor && id->device == device)
89 			break;
90 
91 	return id && id->vendor;
92 }
93 
94 static bool probe_list(struct pci_dev *pdev, unsigned short vendor,
95 		       const unsigned char *rom_list)
96 {
97 	unsigned short device;
98 
99 	do {
100 		if (probe_kernel_address(rom_list, device) != 0)
101 			device = 0;
102 
103 		if (device && match_id(pdev, vendor, device))
104 			break;
105 
106 		rom_list += 2;
107 	} while (device);
108 
109 	return !!device;
110 }
111 
112 static struct resource *find_oprom(struct pci_dev *pdev)
113 {
114 	struct resource *oprom = NULL;
115 	int i;
116 
117 	for (i = 0; i < ARRAY_SIZE(adapter_rom_resources); i++) {
118 		struct resource *res = &adapter_rom_resources[i];
119 		unsigned short offset, vendor, device, list, rev;
120 		const unsigned char *rom;
121 
122 		if (res->end == 0)
123 			break;
124 
125 		rom = isa_bus_to_virt(res->start);
126 		if (probe_kernel_address(rom + 0x18, offset) != 0)
127 			continue;
128 
129 		if (probe_kernel_address(rom + offset + 0x4, vendor) != 0)
130 			continue;
131 
132 		if (probe_kernel_address(rom + offset + 0x6, device) != 0)
133 			continue;
134 
135 		if (match_id(pdev, vendor, device)) {
136 			oprom = res;
137 			break;
138 		}
139 
140 		if (probe_kernel_address(rom + offset + 0x8, list) == 0 &&
141 		    probe_kernel_address(rom + offset + 0xc, rev) == 0 &&
142 		    rev >= 3 && list &&
143 		    probe_list(pdev, vendor, rom + offset + list)) {
144 			oprom = res;
145 			break;
146 		}
147 	}
148 
149 	return oprom;
150 }
151 
152 void *pci_map_biosrom(struct pci_dev *pdev)
153 {
154 	struct resource *oprom = find_oprom(pdev);
155 
156 	if (!oprom)
157 		return NULL;
158 
159 	return ioremap(oprom->start, resource_size(oprom));
160 }
161 EXPORT_SYMBOL(pci_map_biosrom);
162 
163 void pci_unmap_biosrom(void __iomem *image)
164 {
165 	iounmap(image);
166 }
167 EXPORT_SYMBOL(pci_unmap_biosrom);
168 
169 size_t pci_biosrom_size(struct pci_dev *pdev)
170 {
171 	struct resource *oprom = find_oprom(pdev);
172 
173 	return oprom ? resource_size(oprom) : 0;
174 }
175 EXPORT_SYMBOL(pci_biosrom_size);
176 
177 #define ROMSIGNATURE 0xaa55
178 
179 static int __init romsignature(const unsigned char *rom)
180 {
181 	const unsigned short * const ptr = (const unsigned short *)rom;
182 	unsigned short sig;
183 
184 	return probe_kernel_address(ptr, sig) == 0 && sig == ROMSIGNATURE;
185 }
186 
187 static int __init romchecksum(const unsigned char *rom, unsigned long length)
188 {
189 	unsigned char sum, c;
190 
191 	for (sum = 0; length && probe_kernel_address(rom++, c) == 0; length--)
192 		sum += c;
193 	return !length && !sum;
194 }
195 
196 void __init probe_roms(void)
197 {
198 	const unsigned char *rom;
199 	unsigned long start, length, upper;
200 	unsigned char c;
201 	int i;
202 
203 	/* video rom */
204 	upper = adapter_rom_resources[0].start;
205 	for (start = video_rom_resource.start; start < upper; start += 2048) {
206 		rom = isa_bus_to_virt(start);
207 		if (!romsignature(rom))
208 			continue;
209 
210 		video_rom_resource.start = start;
211 
212 		if (probe_kernel_address(rom + 2, c) != 0)
213 			continue;
214 
215 		/* 0 < length <= 0x7f * 512, historically */
216 		length = c * 512;
217 
218 		/* if checksum okay, trust length byte */
219 		if (length && romchecksum(rom, length))
220 			video_rom_resource.end = start + length - 1;
221 
222 		request_resource(&iomem_resource, &video_rom_resource);
223 		break;
224 	}
225 
226 	start = (video_rom_resource.end + 1 + 2047) & ~2047UL;
227 	if (start < upper)
228 		start = upper;
229 
230 	/* system rom */
231 	request_resource(&iomem_resource, &system_rom_resource);
232 	upper = system_rom_resource.start;
233 
234 	/* check for extension rom (ignore length byte!) */
235 	rom = isa_bus_to_virt(extension_rom_resource.start);
236 	if (romsignature(rom)) {
237 		length = extension_rom_resource.end - extension_rom_resource.start + 1;
238 		if (romchecksum(rom, length)) {
239 			request_resource(&iomem_resource, &extension_rom_resource);
240 			upper = extension_rom_resource.start;
241 		}
242 	}
243 
244 	/* check for adapter roms on 2k boundaries */
245 	for (i = 0; i < ARRAY_SIZE(adapter_rom_resources) && start < upper; start += 2048) {
246 		rom = isa_bus_to_virt(start);
247 		if (!romsignature(rom))
248 			continue;
249 
250 		if (probe_kernel_address(rom + 2, c) != 0)
251 			continue;
252 
253 		/* 0 < length <= 0x7f * 512, historically */
254 		length = c * 512;
255 
256 		/* but accept any length that fits if checksum okay */
257 		if (!length || start + length > upper || !romchecksum(rom, length))
258 			continue;
259 
260 		adapter_rom_resources[i].start = start;
261 		adapter_rom_resources[i].end = start + length - 1;
262 		request_resource(&iomem_resource, &adapter_rom_resources[i]);
263 
264 		start = adapter_rom_resources[i++].end & ~2047UL;
265 	}
266 }
267 
268