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39795f9c DW |
1 | /* |
2 | * probe_roms - scan for Adapter ROMS | |
3 | * | |
4 | * (based on linux-2.6:arch/x86/kernel/probe_roms_32.c) | |
5 | * | |
6 | * Copyright (C) 2008 Intel Corporation | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify it | |
9 | * under the terms and conditions of the GNU General Public License, | |
10 | * version 2, as published by the Free Software Foundation. | |
11 | * | |
12 | * This program is distributed in the hope it will be useful, but WITHOUT | |
13 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
14 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
15 | * more details. | |
16 | * | |
17 | * You should have received a copy of the GNU General Public License along with | |
18 | * this program; if not, write to the Free Software Foundation, Inc., | |
19 | * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA. | |
20 | */ | |
21 | ||
22 | #include "probe_roms.h" | |
23 | #include <unistd.h> | |
24 | #include <signal.h> | |
25 | #include <fcntl.h> | |
26 | #include <sys/mman.h> | |
27 | #include <sys/stat.h> | |
28 | #include <sys/types.h> | |
29 | #include <asm/types.h> | |
30 | ||
31 | static void *rom_mem = MAP_FAILED; | |
32 | static int rom_fd = -1; | |
f21e18ca | 33 | static const int rom_len = 0xf0000 - 0xc0000; /* option-rom memory region */ |
39795f9c | 34 | static int _sigbus; |
969c2555 DW |
35 | static unsigned long rom_align; |
36 | ||
39795f9c DW |
37 | #define ARRAY_SIZE(x) (sizeof(x)/sizeof(x[0])) |
38 | ||
39 | static void sigbus(int sig) | |
40 | { | |
41 | _sigbus = 1; | |
42 | } | |
43 | ||
44 | static int probe_address8(const __u8 *ptr, __u8 *val) | |
45 | { | |
46 | int rc = 0; | |
47 | ||
48 | *val = *ptr; | |
49 | if (_sigbus) | |
50 | rc = -1; | |
51 | _sigbus = 0; | |
52 | ||
53 | return rc; | |
54 | } | |
55 | ||
56 | static int probe_address16(const __u16 *ptr, __u16 *val) | |
57 | { | |
58 | int rc = 0; | |
59 | ||
60 | *val = *ptr; | |
61 | if (_sigbus) | |
62 | rc = -1; | |
63 | _sigbus = 0; | |
64 | ||
65 | return rc; | |
66 | } | |
67 | ||
68 | void probe_roms_exit(void) | |
69 | { | |
70 | signal(SIGBUS, SIG_DFL); | |
71 | if (rom_fd >= 0) { | |
72 | close(rom_fd); | |
73 | rom_fd = -1; | |
74 | } | |
75 | if (rom_mem != MAP_FAILED) { | |
76 | munmap(rom_mem, rom_len); | |
77 | rom_mem = MAP_FAILED; | |
78 | } | |
79 | } | |
80 | ||
969c2555 | 81 | int probe_roms_init(unsigned long align) |
39795f9c | 82 | { |
922f66a9 | 83 | int fd = -1; |
39795f9c DW |
84 | int rc = 0; |
85 | ||
969c2555 DW |
86 | /* valid values are 2048 and 512. 512 is for PCI-3.0 compliant |
87 | * systems, or systems that do not have dangerous/legacy ISA | |
88 | * devices. 2048 should always be safe | |
89 | */ | |
90 | if (align == 512 || align == 2048) | |
91 | rom_align = align; | |
92 | else | |
93 | return -1; | |
94 | ||
39795f9c DW |
95 | if (signal(SIGBUS, sigbus) == SIG_ERR) |
96 | rc = -1; | |
97 | if (rc == 0) { | |
98 | fd = open("/dev/mem", O_RDONLY); | |
99 | if (fd < 0) | |
100 | rc = -1; | |
101 | } | |
102 | if (rc == 0) { | |
103 | rom_mem = mmap(NULL, rom_len, PROT_READ, MAP_PRIVATE, fd, 0xc0000); | |
104 | if (rom_mem == MAP_FAILED) | |
105 | rc = -1; | |
106 | } | |
107 | ||
108 | if (rc == 0) | |
109 | rom_fd = fd; | |
922f66a9 AW |
110 | else { |
111 | if (fd >= 0) | |
112 | close(fd); | |
39795f9c | 113 | probe_roms_exit(); |
922f66a9 | 114 | } |
39795f9c DW |
115 | return rc; |
116 | } | |
117 | ||
118 | /** | |
119 | * isa_bus_to_virt - convert physical address to mmap'd region | |
120 | * @addr - address to convert | |
121 | * | |
122 | * Only valid between a successful call to probe_roms_init and the | |
123 | * corresponding probe_roms_exit | |
124 | */ | |
125 | static void *isa_bus_to_virt(unsigned long addr) | |
126 | { | |
127 | return rom_mem + (addr - 0xc0000); | |
128 | } | |
129 | ||
130 | struct resource { | |
131 | unsigned long start; | |
132 | unsigned long end; | |
133 | const char *name; | |
134 | }; | |
135 | ||
136 | static struct resource system_rom_resource = { | |
137 | .name = "System ROM", | |
138 | .start = 0xf0000, | |
139 | .end = 0xfffff, | |
140 | }; | |
141 | ||
142 | static struct resource extension_rom_resource = { | |
143 | .name = "Extension ROM", | |
144 | .start = 0xe0000, | |
145 | .end = 0xeffff, | |
146 | }; | |
147 | ||
148 | static struct resource adapter_rom_resources[] = { { | |
149 | .name = "Adapter ROM", | |
150 | .start = 0xc8000, | |
151 | .end = 0, | |
152 | }, { | |
153 | .name = "Adapter ROM", | |
154 | .start = 0, | |
155 | .end = 0, | |
156 | }, { | |
157 | .name = "Adapter ROM", | |
158 | .start = 0, | |
159 | .end = 0, | |
160 | }, { | |
161 | .name = "Adapter ROM", | |
162 | .start = 0, | |
163 | .end = 0, | |
164 | }, { | |
165 | .name = "Adapter ROM", | |
166 | .start = 0, | |
167 | .end = 0, | |
168 | }, { | |
169 | .name = "Adapter ROM", | |
170 | .start = 0, | |
171 | .end = 0, | |
172 | } }; | |
173 | ||
174 | static struct resource video_rom_resource = { | |
175 | .name = "Video ROM", | |
176 | .start = 0xc0000, | |
177 | .end = 0xc7fff, | |
178 | }; | |
179 | ||
180 | #define ROMSIGNATURE 0xaa55 | |
181 | ||
182 | static int romsignature(const unsigned char *rom) | |
183 | { | |
184 | const unsigned short * const ptr = (const unsigned short *)rom; | |
185 | unsigned short sig = 0; | |
186 | ||
187 | return probe_address16(ptr, &sig) == 0 && sig == ROMSIGNATURE; | |
188 | } | |
189 | ||
190 | static int romchecksum(const unsigned char *rom, unsigned long length) | |
191 | { | |
192 | unsigned char sum, c; | |
193 | ||
194 | for (sum = 0; length && probe_address8(rom++, &c) == 0; length--) | |
195 | sum += c; | |
196 | return !length && !sum; | |
197 | } | |
198 | ||
199 | int scan_adapter_roms(scan_fn fn) | |
200 | { | |
201 | /* let scan_fn examing each of the adapter roms found by probe_roms */ | |
f21e18ca | 202 | unsigned int i; |
39795f9c DW |
203 | int found; |
204 | ||
205 | if (rom_fd < 0) | |
206 | return 0; | |
207 | ||
208 | found = 0; | |
209 | for (i = 0; i < ARRAY_SIZE(adapter_rom_resources); i++) { | |
210 | struct resource *res = &adapter_rom_resources[i]; | |
211 | ||
212 | if (res->start) { | |
213 | found = fn(isa_bus_to_virt(res->start), | |
214 | isa_bus_to_virt(res->end)); | |
215 | if (found) | |
216 | break; | |
217 | } else | |
218 | break; | |
219 | } | |
220 | ||
221 | return found; | |
222 | } | |
223 | ||
969c2555 DW |
224 | static unsigned long align(unsigned long addr, unsigned long alignment) |
225 | { | |
226 | return (addr + alignment - 1) & ~(alignment - 1); | |
227 | } | |
228 | ||
39795f9c DW |
229 | void probe_roms(void) |
230 | { | |
231 | const void *rom; | |
232 | unsigned long start, length, upper; | |
233 | unsigned char c; | |
f21e18ca | 234 | unsigned int i; |
39795f9c DW |
235 | |
236 | if (rom_fd < 0) | |
237 | return; | |
238 | ||
239 | /* video rom */ | |
240 | upper = adapter_rom_resources[0].start; | |
969c2555 | 241 | for (start = video_rom_resource.start; start < upper; start += rom_align) { |
39795f9c DW |
242 | rom = isa_bus_to_virt(start); |
243 | if (!romsignature(rom)) | |
244 | continue; | |
245 | ||
246 | video_rom_resource.start = start; | |
247 | ||
248 | if (probe_address8(rom + 2, &c) != 0) | |
249 | continue; | |
250 | ||
251 | /* 0 < length <= 0x7f * 512, historically */ | |
252 | length = c * 512; | |
253 | ||
254 | /* if checksum okay, trust length byte */ | |
255 | if (length && romchecksum(rom, length)) | |
256 | video_rom_resource.end = start + length - 1; | |
257 | break; | |
258 | } | |
259 | ||
969c2555 | 260 | start = align(video_rom_resource.end + 1, rom_align); |
39795f9c DW |
261 | if (start < upper) |
262 | start = upper; | |
263 | ||
264 | /* system rom */ | |
265 | upper = system_rom_resource.start; | |
266 | ||
267 | /* check for extension rom (ignore length byte!) */ | |
268 | rom = isa_bus_to_virt(extension_rom_resource.start); | |
269 | if (romsignature(rom)) { | |
270 | length = extension_rom_resource.end - extension_rom_resource.start + 1; | |
271 | if (romchecksum(rom, length)) | |
272 | upper = extension_rom_resource.start; | |
273 | } | |
274 | ||
275 | /* check for adapter roms on 2k boundaries */ | |
969c2555 | 276 | for (i = 0; i < ARRAY_SIZE(adapter_rom_resources) && start < upper; start += rom_align) { |
39795f9c DW |
277 | rom = isa_bus_to_virt(start); |
278 | if (!romsignature(rom)) | |
279 | continue; | |
280 | ||
281 | if (probe_address8(rom + 2, &c) != 0) | |
282 | continue; | |
283 | ||
284 | /* 0 < length <= 0x7f * 512, historically */ | |
285 | length = c * 512; | |
286 | ||
287 | /* but accept any length that fits if checksum okay */ | |
288 | if (!length || start + length > upper || !romchecksum(rom, length)) | |
289 | continue; | |
290 | ||
291 | adapter_rom_resources[i].start = start; | |
292 | adapter_rom_resources[i].end = start + length - 1; | |
293 | ||
969c2555 | 294 | start = adapter_rom_resources[i++].end & ~(rom_align - 1); |
39795f9c DW |
295 | } |
296 | } | |
297 |