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 roms_deinit(void);
  39 static int roms_init(void);
  40
  41 static void sigbus(int sig)
  42 {
  43         _sigbus = 1;
  44 }
  45
  46 static int probe_address8(const __u8 *ptr, __u8 *val)
  47 {
  48         int rc = 0;
  49
  50         *val = *ptr;
  51         if (_sigbus)
  52                 rc = -1;
  53         _sigbus = 0;
  54
  55         return rc;
  56 }
  57
  58 static int probe_address16(const __u16 *ptr, __u16 *val)
  59 {
  60         int rc = 0;
  61
  62         *val = *ptr;
  63         if (_sigbus)
  64                 rc = -1;
  65         _sigbus = 0;
  66
  67         return rc;
  68 }
  69
  70 void probe_roms_exit(void)
  71 {
  72         signal(SIGBUS, SIG_DFL);
  73         if (rom_fd >= 0) {
  74                 close(rom_fd);
  75                 rom_fd = -1;
  76         }
  77         if (rom_mem != MAP_FAILED) {
  78                 munmap(rom_mem, rom_len);
  79                 rom_mem = MAP_FAILED;
  80         }
  81         roms_deinit();
  82 }
  83
  84 int probe_roms_init(unsigned long align)
  85 {
  86         int fd = -1;
  87         int rc = 0;
  88
  89         /* valid values are 2048 and 512.  512 is for PCI-3.0 compliant
  90          * systems, or systems that do not have dangerous/legacy ISA
  91          * devices.  2048 should always be safe
  92          */
  93         if (align == 512 || align == 2048)
  94                 rom_align = align;
  95         else
  96                 return -1;
  97
  98         if (roms_init())
  99                 return -1;
 100
 101         if (signal(SIGBUS, sigbus) == SIG_ERR)
 102                 rc = -1;
 103         if (rc == 0) {
 104                 fd = open("/dev/mem", O_RDONLY);
 105                 if (fd < 0)
 106                         rc = -1;
 107         }
 108         if (rc == 0) {
 109                 rom_mem = mmap(NULL, rom_len, PROT_READ, MAP_PRIVATE, fd, 0xc0000);
 110                 if (rom_mem == MAP_FAILED)
 111                         rc = -1;
 112         }
 113
 114         if (rc == 0)
 115                 rom_fd = fd;
 116         else {
 117                 if (fd >= 0)
 118                         close(fd);
 119                 probe_roms_exit();
 120         }
 121         return rc;
 122 }
 123
 124 /**
 125  * isa_bus_to_virt - convert physical address to mmap'd region
 126  * @addr - address to convert
 127  *
 128  * Only valid between a successful call to probe_roms_init and the
 129  * corresponding probe_roms_exit
 130  */
 131 static void *isa_bus_to_virt(unsigned long addr)
 132 {
 133         return rom_mem + (addr - 0xc0000);
 134 }
 135
 136 struct resource {
 137         unsigned long start;
 138         unsigned long end;
 139         unsigned long data;
 140         const char *name;
 141         struct resource *next;
 142 };
 143
 144 static struct resource system_rom_resource = {
 145         .name   = "System ROM",
 146         .start  = 0xf0000,
 147         .data   = 0,
 148         .end    = 0xfffff,
 149 };
 150
 151 static struct resource extension_rom_resource = {
 152         .name   = "Extension ROM",
 153         .start  = 0xe0000,
 154         .data   = 0,
 155         .end    = 0xeffff,
 156 };
 157
 158 static struct resource *adapter_rom_resources;
 159
 160 static struct resource video_rom_resource = {
 161         .name   = "Video ROM",
 162         .start  = 0xc0000,
 163         .data   = 0,
 164         .end    = 0xc7fff,
 165 };
 166
 167 static int roms_init(void)
 168 {
 169         adapter_rom_resources = malloc(sizeof(struct resource));
 170         if (adapter_rom_resources == NULL)
 171                 return 1;
 172         adapter_rom_resources->name = "Adapter ROM";
 173         adapter_rom_resources->start = 0xc8000;
 174         adapter_rom_resources->data = 0;
 175         adapter_rom_resources->end = 0;
 176         adapter_rom_resources->next = NULL;
 177         return 0;
 178 }
 179
 180 static void roms_deinit(void)
 181 {
 182         struct resource *res;
 183
 184         res = adapter_rom_resources;
 185         while (res) {
 186                 struct resource *tmp = res;
 187
 188                 res = res->next;
 189                 free(tmp);
 190         }
 191 }
 192
 193 #define ROMSIGNATURE 0xaa55
 194
 195
 196 static int romsignature(const unsigned char *rom)
 197 {
 198         const unsigned short * const ptr = (const unsigned short *)rom;
 199         unsigned short sig = 0;
 200
 201         return probe_address16(ptr, &sig) == 0 && sig == ROMSIGNATURE;
 202 }
 203
 204 static int romchecksum(const unsigned char *rom, unsigned long length)
 205 {
 206         unsigned char sum, c;
 207
 208         for (sum = 0; length && probe_address8(rom++, &c) == 0; length--)
 209                 sum += c;
 210         return !length && !sum;
 211 }
 212
 213 int scan_adapter_roms(scan_fn fn)
 214 {
 215         /* let scan_fn examing each of the adapter roms found by probe_roms */
 216         struct resource *res = adapter_rom_resources;
 217         int found;
 218
 219         if (rom_fd < 0)
 220                 return 0;
 221
 222         found = 0;
 223         while (res) {
 224                 if (res->start) {
 225                         found = fn(isa_bus_to_virt(res->start),
 226                                    isa_bus_to_virt(res->end),
 227                                    isa_bus_to_virt(res->data));
 228                         if (found)
 229                                 break;
 230                 } else
 231                         break;
 232                 res = res->next;
 233         }
 234
 235         return found;
 236 }
 237
 238 static unsigned long align(unsigned long addr, unsigned long alignment)
 239 {
 240         return (addr + alignment - 1) & ~(alignment - 1);
 241 }
 242
 243 void probe_roms(void)
 244 {
 245         const void *rom;
 246         unsigned long start, length, upper;
 247         unsigned char c;
 248         struct resource *res = adapter_rom_resources;
 249         __u16 val=0;
 250
 251         if (rom_fd < 0)
 252                 return;
 253
 254         /* video rom */
 255         upper = res->start;
 256         for (start = video_rom_resource.start; start < upper; start += rom_align) {
 257                 rom = isa_bus_to_virt(start);
 258                 if (!romsignature(rom))
 259                         continue;
 260
 261                 video_rom_resource.start = start;
 262
 263                 if (probe_address8(rom + 2, &c) != 0)
 264                         continue;
 265
 266                 /* 0 < length <= 0x7f * 512, historically */
 267                 length = c * 512;
 268
 269                 /* if checksum okay, trust length byte */
 270                 if (length && romchecksum(rom, length))
 271                         video_rom_resource.end = start + length - 1;
 272                 break;
 273         }
 274
 275         start = align(video_rom_resource.end + 1, rom_align);
 276         if (start < upper)
 277                 start = upper;
 278
 279         /* system rom */
 280         upper = system_rom_resource.start;
 281
 282         /* check for extension rom (ignore length byte!) */
 283         rom = isa_bus_to_virt(extension_rom_resource.start);
 284         if (romsignature(rom)) {
 285                 length = extension_rom_resource.end - extension_rom_resource.start + 1;
 286                 if (romchecksum(rom, length))
 287                         upper = extension_rom_resource.start;
 288         }
 289
 290         struct resource *prev_res = res;
 291         /* check for adapter roms on 2k boundaries */
 292         for (; start < upper; start += rom_align) {
 293                 rom = isa_bus_to_virt(start);
 294                 if (!romsignature(rom))
 295                         continue;
 296
 297                 if (probe_address8(rom + 2, &c) != 0)
 298                         continue;
 299
 300                 /* 0 < length <= 0x7f * 512, historically */
 301                 length = c * 512;
 302
 303                 /* Retrieve 16-bit pointer to PCI Data Structure (offset 18h-19h)
 304                  * The data can be within 64KB forward of the first location
 305                  * of this code image. The pointer is in little-endian order
 306                  */
 307
 308                 if (probe_address16(rom + 0x18, &val) != 0)
 309                         continue;
 310                 val = __le16_to_cpu(val);
 311
 312                 /* but accept any length that fits if checksum okay */
 313                 if (!length || start + length > upper || !romchecksum(rom, length))
 314                         continue;
 315
 316                 if (res == NULL) {
 317                         res = calloc(1, sizeof(struct resource));
 318                         if (res == NULL)
 319                                 return;
 320                         prev_res->next = res;
 321                 }
 322
 323                 res->start = start;
 324                 res->data = start + (unsigned long)val;
 325                 res->end = start + length - 1;
 326
 327                 start = res->end & ~(rom_align - 1);
 328                 prev_res = res;
 329                 res = res->next;
 330         }
 331 }