xref: /openbmc/linux/arch/x86/kernel/probe_roms.c (revision 9cfc5c90)
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 <linux/export.h>
14 
15 #include <asm/probe_roms.h>
16 #include <asm/pci-direct.h>
17 #include <asm/e820.h>
18 #include <asm/mmzone.h>
19 #include <asm/setup.h>
20 #include <asm/sections.h>
21 #include <asm/io.h>
22 #include <asm/setup_arch.h>
23 
24 static struct resource system_rom_resource = {
25 	.name	= "System ROM",
26 	.start	= 0xf0000,
27 	.end	= 0xfffff,
28 	.flags	= IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
29 };
30 
31 static struct resource extension_rom_resource = {
32 	.name	= "Extension ROM",
33 	.start	= 0xe0000,
34 	.end	= 0xeffff,
35 	.flags	= IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
36 };
37 
38 static struct resource adapter_rom_resources[] = { {
39 	.name 	= "Adapter ROM",
40 	.start	= 0xc8000,
41 	.end	= 0,
42 	.flags	= IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
43 }, {
44 	.name 	= "Adapter ROM",
45 	.start	= 0,
46 	.end	= 0,
47 	.flags	= IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
48 }, {
49 	.name 	= "Adapter ROM",
50 	.start	= 0,
51 	.end	= 0,
52 	.flags	= IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
53 }, {
54 	.name 	= "Adapter ROM",
55 	.start	= 0,
56 	.end	= 0,
57 	.flags	= IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
58 }, {
59 	.name 	= "Adapter ROM",
60 	.start	= 0,
61 	.end	= 0,
62 	.flags	= IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
63 }, {
64 	.name 	= "Adapter ROM",
65 	.start	= 0,
66 	.end	= 0,
67 	.flags	= IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
68 } };
69 
70 static struct resource video_rom_resource = {
71 	.name 	= "Video ROM",
72 	.start	= 0xc0000,
73 	.end	= 0xc7fff,
74 	.flags	= IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
75 };
76 
77 /* does this oprom support the given pci device, or any of the devices
78  * that the driver supports?
79  */
80 static bool match_id(struct pci_dev *pdev, unsigned short vendor, unsigned short device)
81 {
82 	struct pci_driver *drv = pdev->driver;
83 	const struct pci_device_id *id;
84 
85 	if (pdev->vendor == vendor && pdev->device == device)
86 		return true;
87 
88 	for (id = drv ? drv->id_table : NULL; id && id->vendor; id++)
89 		if (id->vendor == vendor && id->device == device)
90 			break;
91 
92 	return id && id->vendor;
93 }
94 
95 static bool probe_list(struct pci_dev *pdev, unsigned short vendor,
96 		       const unsigned char *rom_list)
97 {
98 	unsigned short device;
99 
100 	do {
101 		if (probe_kernel_address(rom_list, device) != 0)
102 			device = 0;
103 
104 		if (device && match_id(pdev, vendor, device))
105 			break;
106 
107 		rom_list += 2;
108 	} while (device);
109 
110 	return !!device;
111 }
112 
113 static struct resource *find_oprom(struct pci_dev *pdev)
114 {
115 	struct resource *oprom = NULL;
116 	int i;
117 
118 	for (i = 0; i < ARRAY_SIZE(adapter_rom_resources); i++) {
119 		struct resource *res = &adapter_rom_resources[i];
120 		unsigned short offset, vendor, device, list, rev;
121 		const unsigned char *rom;
122 
123 		if (res->end == 0)
124 			break;
125 
126 		rom = isa_bus_to_virt(res->start);
127 		if (probe_kernel_address(rom + 0x18, offset) != 0)
128 			continue;
129 
130 		if (probe_kernel_address(rom + offset + 0x4, vendor) != 0)
131 			continue;
132 
133 		if (probe_kernel_address(rom + offset + 0x6, device) != 0)
134 			continue;
135 
136 		if (match_id(pdev, vendor, device)) {
137 			oprom = res;
138 			break;
139 		}
140 
141 		if (probe_kernel_address(rom + offset + 0x8, list) == 0 &&
142 		    probe_kernel_address(rom + offset + 0xc, rev) == 0 &&
143 		    rev >= 3 && list &&
144 		    probe_list(pdev, vendor, rom + offset + list)) {
145 			oprom = res;
146 			break;
147 		}
148 	}
149 
150 	return oprom;
151 }
152 
153 void __iomem *pci_map_biosrom(struct pci_dev *pdev)
154 {
155 	struct resource *oprom = find_oprom(pdev);
156 
157 	if (!oprom)
158 		return NULL;
159 
160 	return ioremap(oprom->start, resource_size(oprom));
161 }
162 EXPORT_SYMBOL(pci_map_biosrom);
163 
164 void pci_unmap_biosrom(void __iomem *image)
165 {
166 	iounmap(image);
167 }
168 EXPORT_SYMBOL(pci_unmap_biosrom);
169 
170 size_t pci_biosrom_size(struct pci_dev *pdev)
171 {
172 	struct resource *oprom = find_oprom(pdev);
173 
174 	return oprom ? resource_size(oprom) : 0;
175 }
176 EXPORT_SYMBOL(pci_biosrom_size);
177 
178 #define ROMSIGNATURE 0xaa55
179 
180 static int __init romsignature(const unsigned char *rom)
181 {
182 	const unsigned short * const ptr = (const unsigned short *)rom;
183 	unsigned short sig;
184 
185 	return probe_kernel_address(ptr, sig) == 0 && sig == ROMSIGNATURE;
186 }
187 
188 static int __init romchecksum(const unsigned char *rom, unsigned long length)
189 {
190 	unsigned char sum, c;
191 
192 	for (sum = 0; length && probe_kernel_address(rom++, c) == 0; length--)
193 		sum += c;
194 	return !length && !sum;
195 }
196 
197 void __init probe_roms(void)
198 {
199 	const unsigned char *rom;
200 	unsigned long start, length, upper;
201 	unsigned char c;
202 	int i;
203 
204 	/* video rom */
205 	upper = adapter_rom_resources[0].start;
206 	for (start = video_rom_resource.start; start < upper; start += 2048) {
207 		rom = isa_bus_to_virt(start);
208 		if (!romsignature(rom))
209 			continue;
210 
211 		video_rom_resource.start = start;
212 
213 		if (probe_kernel_address(rom + 2, c) != 0)
214 			continue;
215 
216 		/* 0 < length <= 0x7f * 512, historically */
217 		length = c * 512;
218 
219 		/* if checksum okay, trust length byte */
220 		if (length && romchecksum(rom, length))
221 			video_rom_resource.end = start + length - 1;
222 
223 		request_resource(&iomem_resource, &video_rom_resource);
224 		break;
225 	}
226 
227 	start = (video_rom_resource.end + 1 + 2047) & ~2047UL;
228 	if (start < upper)
229 		start = upper;
230 
231 	/* system rom */
232 	request_resource(&iomem_resource, &system_rom_resource);
233 	upper = system_rom_resource.start;
234 
235 	/* check for extension rom (ignore length byte!) */
236 	rom = isa_bus_to_virt(extension_rom_resource.start);
237 	if (romsignature(rom)) {
238 		length = resource_size(&extension_rom_resource);
239 		if (romchecksum(rom, length)) {
240 			request_resource(&iomem_resource, &extension_rom_resource);
241 			upper = extension_rom_resource.start;
242 		}
243 	}
244 
245 	/* check for adapter roms on 2k boundaries */
246 	for (i = 0; i < ARRAY_SIZE(adapter_rom_resources) && start < upper; start += 2048) {
247 		rom = isa_bus_to_virt(start);
248 		if (!romsignature(rom))
249 			continue;
250 
251 		if (probe_kernel_address(rom + 2, c) != 0)
252 			continue;
253 
254 		/* 0 < length <= 0x7f * 512, historically */
255 		length = c * 512;
256 
257 		/* but accept any length that fits if checksum okay */
258 		if (!length || start + length > upper || !romchecksum(rom, length))
259 			continue;
260 
261 		adapter_rom_resources[i].start = start;
262 		adapter_rom_resources[i].end = start + length - 1;
263 		request_resource(&iomem_resource, &adapter_rom_resources[i]);
264 
265 		start = adapter_rom_resources[i++].end & ~2047UL;
266 	}
267 }
268 
269