probe_roms.c

   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 "mdadm.h"
  24 #include <unistd.h>
  25 #include <signal.h>
  26 #include <fcntl.h>
  27 #include <sys/mman.h>
  28 #include <sys/stat.h>
  29 #include <sys/types.h>
  30 #include <asm/types.h>
  31
  32 static void *rom_mem = MAP_FAILED;
  33 static int rom_fd = -1;
  34 static const int rom_len = 0xf0000 - 0xc0000; /* option-rom memory region */
  35 static int _sigbus;
  36 static unsigned long rom_align;
  37
  38 #define ARRAY_SIZE(x) (sizeof(x)/sizeof(x[0]))
  39
  40 static void sigbus(int sig)
  41 {
  42         _sigbus = 1;
  43 }
  44
  45 static int probe_address8(const __u8 *ptr, __u8 *val)
  46 {
  47         int rc = 0;
  48
  49         *val = *ptr;
  50         if (_sigbus)
  51                 rc = -1;
  52         _sigbus = 0;
  53
  54         return rc;
  55 }
  56
  57 static int probe_address16(const __u16 *ptr, __u16 *val)
  58 {
  59         int rc = 0;
  60
  61         *val = *ptr;
  62         if (_sigbus)
  63                 rc = -1;
  64         _sigbus = 0;
  65
  66         return rc;
  67 }
  68
  69 void probe_roms_exit(void)
  70 {
  71         signal(SIGBUS, SIG_DFL);
  72         if (rom_fd >= 0) {
  73                 close(rom_fd);
  74                 rom_fd = -1;
  75         }
  76         if (rom_mem != MAP_FAILED) {
  77                 munmap(rom_mem, rom_len);
  78                 rom_mem = MAP_FAILED;
  79         }
  80 }
  81
  82 int probe_roms_init(unsigned long align)
  83 {
  84         int fd = -1;
  85         int rc = 0;
  86
  87         /* valid values are 2048 and 512.  512 is for PCI-3.0 compliant
  88          * systems, or systems that do not have dangerous/legacy ISA
  89          * devices.  2048 should always be safe
  90          */
  91         if (align == 512 || align == 2048)
  92                 rom_align = align;
  93         else
  94                 return -1;
  95
  96         if (signal(SIGBUS, sigbus) == SIG_ERR)
  97                 rc = -1;
  98         if (rc == 0) {
  99                 fd = open("/dev/mem", O_RDONLY);
 100                 if (fd < 0)
 101                         rc = -1;
 102         }
 103         if (rc == 0) {
 104                 rom_mem = mmap(NULL, rom_len, PROT_READ, MAP_PRIVATE, fd, 0xc0000);
 105                 if (rom_mem == MAP_FAILED)
 106                         rc = -1;
 107         }
 108
 109         if (rc == 0)
 110                 rom_fd = fd;
 111         else {
 112                 if (fd >= 0)
 113                         close(fd);
 114                 probe_roms_exit();
 115         }
 116         return rc;
 117 }
 118
 119 /**
 120  * isa_bus_to_virt - convert physical address to mmap'd region
 121  * @addr - address to convert
 122  *
 123  * Only valid between a successful call to probe_roms_init and the
 124  * corresponding probe_roms_exit
 125  */
 126 static void *isa_bus_to_virt(unsigned long addr)
 127 {
 128         return rom_mem + (addr - 0xc0000);
 129 }
 130
 131 struct resource {
 132         unsigned long start;
 133         unsigned long end;
 134         unsigned long data;
 135         const char *name;
 136 };
 137
 138 static struct resource system_rom_resource = {
 139         .name   = "System ROM",
 140         .start  = 0xf0000,
 141         .data   = 0,
 142         .end    = 0xfffff,
 143 };
 144
 145 static struct resource extension_rom_resource = {
 146         .name   = "Extension ROM",
 147         .start  = 0xe0000,
 148         .data   = 0,
 149         .end    = 0xeffff,
 150 };
 151
 152 static struct resource adapter_rom_resources[] = { {
 153         .name   = "Adapter ROM",
 154         .start  = 0xc8000,
 155         .data   = 0,
 156         .end    = 0,
 157 }, {
 158         .name   = "Adapter ROM",
 159         .start  = 0,
 160         .data   = 0,
 161         .end    = 0,
 162 }, {
 163         .name   = "Adapter ROM",
 164         .start  = 0,
 165         .data   = 0,
 166         .end    = 0,
 167 }, {
 168         .name   = "Adapter ROM",
 169         .start  = 0,
 170         .data   = 0,
 171         .end    = 0,
 172 }, {
 173         .name   = "Adapter ROM",
 174         .start  = 0,
 175         .data   = 0,
 176         .end    = 0,
 177 }, {
 178         .name   = "Adapter ROM",
 179         .start  = 0,
 180         .data   = 0,
 181         .end    = 0,
 182 } };
 183
 184 static struct resource video_rom_resource = {
 185         .name   = "Video ROM",
 186         .start  = 0xc0000,
 187         .data   = 0,
 188         .end    = 0xc7fff,
 189 };
 190
 191 #define ROMSIGNATURE 0xaa55
 192
 193 static int romsignature(const unsigned char *rom)
 194 {
 195         const unsigned short * const ptr = (const unsigned short *)rom;
 196         unsigned short sig = 0;
 197
 198         return probe_address16(ptr, &sig) == 0 && sig == ROMSIGNATURE;
 199 }
 200
 201 static int romchecksum(const unsigned char *rom, unsigned long length)
 202 {
 203         unsigned char sum, c;
 204
 205         for (sum = 0; length && probe_address8(rom++, &c) == 0; length--)
 206                 sum += c;
 207         return !length && !sum;
 208 }
 209
 210 int scan_adapter_roms(scan_fn fn)
 211 {
 212         /* let scan_fn examing each of the adapter roms found by probe_roms */
 213         unsigned int i;
 214         int found;
 215
 216         if (rom_fd < 0)
 217                 return 0;
 218
 219         found = 0;
 220         for (i = 0; i < ARRAY_SIZE(adapter_rom_resources); i++) {
 221                 struct resource *res = &adapter_rom_resources[i];
 222
 223                 if (res->start) {
 224                         found = fn(isa_bus_to_virt(res->start),
 225                                    isa_bus_to_virt(res->end),
 226                                    isa_bus_to_virt(res->data));
 227                         if (found)
 228                                 break;
 229                 } else
 230                         break;
 231         }
 232
 233         return found;
 234 }
 235
 236 static unsigned long align(unsigned long addr, unsigned long alignment)
 237 {
 238         return (addr + alignment - 1) & ~(alignment - 1);
 239 }
 240
 241 void probe_roms(void)
 242 {
 243         const void *rom;
 244         unsigned long start, length, upper;
 245         unsigned char c;
 246         unsigned int i;
 247         __u16 val=0;
 248
 249         if (rom_fd < 0)
 250                 return;
 251
 252         /* video rom */
 253         upper = adapter_rom_resources[0].start;
 254         for (start = video_rom_resource.start; start < upper; start += rom_align) {
 255                 rom = isa_bus_to_virt(start);
 256                 if (!romsignature(rom))
 257                         continue;
 258
 259                 video_rom_resource.start = start;
 260
 261                 if (probe_address8(rom + 2, &c) != 0)
 262                         continue;
 263
 264                 /* 0 < length <= 0x7f * 512, historically */
 265                 length = c * 512;
 266
 267                 /* if checksum okay, trust length byte */
 268                 if (length && romchecksum(rom, length))
 269                         video_rom_resource.end = start + length - 1;
 270                 break;
 271         }
 272
 273         start = align(video_rom_resource.end + 1, rom_align);
 274         if (start < upper)
 275                 start = upper;
 276
 277         /* system rom */
 278         upper = system_rom_resource.start;
 279
 280         /* check for extension rom (ignore length byte!) */
 281         rom = isa_bus_to_virt(extension_rom_resource.start);
 282         if (romsignature(rom)) {
 283                 length = extension_rom_resource.end - extension_rom_resource.start + 1;
 284                 if (romchecksum(rom, length))
 285                         upper = extension_rom_resource.start;
 286         }
 287
 288         /* check for adapter roms on 2k boundaries */
 289         for (i = 0; i < ARRAY_SIZE(adapter_rom_resources) && start < upper; start += rom_align) {
 290                 rom = isa_bus_to_virt(start);
 291                 if (!romsignature(rom))
 292                         continue;
 293
 294                 if (probe_address8(rom + 2, &c) != 0)
 295                         continue;
 296
 297                 /* 0 < length <= 0x7f * 512, historically */
 298                 length = c * 512;
 299
 300                 /* Retrieve 16-bit pointer to PCI Data Structure (offset 18h-19h)
 301                  * The data can be within 64KB forward of the first location
 302                  * of this code image. The pointer is in little-endian order
 303                  */
 304
 305                 if (probe_address16(rom + 0x18, &val) != 0)
 306                         continue;
 307                 val = __le16_to_cpu(val);
 308
 309                 /* but accept any length that fits if checksum okay */
 310                 if (!length || start + length > upper || !romchecksum(rom, length))
 311                         continue;
 312
 313                 adapter_rom_resources[i].start = start;
 314                 adapter_rom_resources[i].data = start + (unsigned long) val;
 315                 adapter_rom_resources[i].end = start + length - 1;
 316
 317                 start = adapter_rom_resources[i++].end & ~(rom_align - 1);
 318         }
 319 }