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