drivers/thunderbolt/eeprom.c

   1 /*
   2  * Thunderbolt Cactus Ridge driver - eeprom access
   3  *
   4  * Copyright (c) 2014 Andreas Noever <andreas.noever@gmail.com>
   5  */
   6
   7 #include <linux/crc32.h>
   8 #include <linux/slab.h>
   9 #include "tb.h"
  10
  11 /**
  12  * tb_eeprom_ctl_write() - write control word
  13  */
  14 static int tb_eeprom_ctl_write(struct tb_switch *sw, struct tb_eeprom_ctl *ctl)
  15 {
  16         return tb_sw_write(sw, ctl, TB_CFG_SWITCH, sw->cap_plug_events + 4, 1);
  17 }
  18
  19 /**
  20  * tb_eeprom_ctl_write() - read control word
  21  */
  22 static int tb_eeprom_ctl_read(struct tb_switch *sw, struct tb_eeprom_ctl *ctl)
  23 {
  24         return tb_sw_read(sw, ctl, TB_CFG_SWITCH, sw->cap_plug_events + 4, 1);
  25 }
  26
  27 enum tb_eeprom_transfer {
  28         TB_EEPROM_IN,
  29         TB_EEPROM_OUT,
  30 };
  31
  32 /**
  33  * tb_eeprom_active - enable rom access
  34  *
  35  * WARNING: Always disable access after usage. Otherwise the controller will
  36  * fail to reprobe.
  37  */
  38 static int tb_eeprom_active(struct tb_switch *sw, bool enable)
  39 {
  40         struct tb_eeprom_ctl ctl;
  41         int res = tb_eeprom_ctl_read(sw, &ctl);
  42         if (res)
  43                 return res;
  44         if (enable) {
  45                 ctl.access_high = 1;
  46                 res = tb_eeprom_ctl_write(sw, &ctl);
  47                 if (res)
  48                         return res;
  49                 ctl.access_low = 0;
  50                 return tb_eeprom_ctl_write(sw, &ctl);
  51         } else {
  52                 ctl.access_low = 1;
  53                 res = tb_eeprom_ctl_write(sw, &ctl);
  54                 if (res)
  55                         return res;
  56                 ctl.access_high = 0;
  57                 return tb_eeprom_ctl_write(sw, &ctl);
  58         }
  59 }
  60
  61 /**
  62  * tb_eeprom_transfer - transfer one bit
  63  *
  64  * If TB_EEPROM_IN is passed, then the bit can be retrieved from ctl->data_in.
  65  * If TB_EEPROM_OUT is passed, then ctl->data_out will be written.
  66  */
  67 static int tb_eeprom_transfer(struct tb_switch *sw, struct tb_eeprom_ctl *ctl,
  68                               enum tb_eeprom_transfer direction)
  69 {
  70         int res;
  71         if (direction == TB_EEPROM_OUT) {
  72                 res = tb_eeprom_ctl_write(sw, ctl);
  73                 if (res)
  74                         return res;
  75         }
  76         ctl->clock = 1;
  77         res = tb_eeprom_ctl_write(sw, ctl);
  78         if (res)
  79                 return res;
  80         if (direction == TB_EEPROM_IN) {
  81                 res = tb_eeprom_ctl_read(sw, ctl);
  82                 if (res)
  83                         return res;
  84         }
  85         ctl->clock = 0;
  86         return tb_eeprom_ctl_write(sw, ctl);
  87 }
  88
  89 /**
  90  * tb_eeprom_out - write one byte to the bus
  91  */
  92 static int tb_eeprom_out(struct tb_switch *sw, u8 val)
  93 {
  94         struct tb_eeprom_ctl ctl;
  95         int i;
  96         int res = tb_eeprom_ctl_read(sw, &ctl);
  97         if (res)
  98                 return res;
  99         for (i = 0; i < 8; i++) {
 100                 ctl.data_out = val & 0x80;
 101                 res = tb_eeprom_transfer(sw, &ctl, TB_EEPROM_OUT);
 102                 if (res)
 103                         return res;
 104                 val <<= 1;
 105         }
 106         return 0;
 107 }
 108
 109 /**
 110  * tb_eeprom_in - read one byte from the bus
 111  */
 112 static int tb_eeprom_in(struct tb_switch *sw, u8 *val)
 113 {
 114         struct tb_eeprom_ctl ctl;
 115         int i;
 116         int res = tb_eeprom_ctl_read(sw, &ctl);
 117         if (res)
 118                 return res;
 119         *val = 0;
 120         for (i = 0; i < 8; i++) {
 121                 *val <<= 1;
 122                 res = tb_eeprom_transfer(sw, &ctl, TB_EEPROM_IN);
 123                 if (res)
 124                         return res;
 125                 *val |= ctl.data_in;
 126         }
 127         return 0;
 128 }
 129
 130 /**
 131  * tb_eeprom_read_n - read count bytes from offset into val
 132  */
 133 static int tb_eeprom_read_n(struct tb_switch *sw, u16 offset, u8 *val,
 134                 size_t count)
 135 {
 136         int i, res;
 137         res = tb_eeprom_active(sw, true);
 138         if (res)
 139                 return res;
 140         res = tb_eeprom_out(sw, 3);
 141         if (res)
 142                 return res;
 143         res = tb_eeprom_out(sw, offset >> 8);
 144         if (res)
 145                 return res;
 146         res = tb_eeprom_out(sw, offset);
 147         if (res)
 148                 return res;
 149         for (i = 0; i < count; i++) {
 150                 res = tb_eeprom_in(sw, val + i);
 151                 if (res)
 152                         return res;
 153         }
 154         return tb_eeprom_active(sw, false);
 155 }
 156
 157 static u8 tb_crc8(u8 *data, int len)
 158 {
 159         int i, j;
 160         u8 val = 0xff;
 161         for (i = 0; i < len; i++) {
 162                 val ^= data[i];
 163                 for (j = 0; j < 8; j++)
 164                         val = (val << 1) ^ ((val & 0x80) ? 7 : 0);
 165         }
 166         return val;
 167 }
 168
 169 static u32 tb_crc32(void *data, size_t len)
 170 {
 171         return ~__crc32c_le(~0, data, len);
 172 }
 173
 174 #define TB_DROM_DATA_START 13
 175 struct tb_drom_header {
 176         /* BYTE 0 */
 177         u8 uid_crc8; /* checksum for uid */
 178         /* BYTES 1-8 */
 179         u64 uid;
 180         /* BYTES 9-12 */
 181         u32 data_crc32; /* checksum for data_len bytes starting at byte 13 */
 182         /* BYTE 13 */
 183         u8 device_rom_revision; /* should be <= 1 */
 184         u16 data_len:10;
 185         u8 __unknown1:6;
 186         /* BYTES 16-21 */
 187         u16 vendor_id;
 188         u16 model_id;
 189         u8 model_rev;
 190         u8 eeprom_rev;
 191 } __packed;
 192
 193 enum tb_drom_entry_type {
 194         /* force unsigned to prevent "one-bit signed bitfield" warning */
 195         TB_DROM_ENTRY_GENERIC = 0U,
 196         TB_DROM_ENTRY_PORT,
 197 };
 198
 199 struct tb_drom_entry_header {
 200         u8 len;
 201         u8 index:6;
 202         bool port_disabled:1; /* only valid if type is TB_DROM_ENTRY_PORT */
 203         enum tb_drom_entry_type type:1;
 204 } __packed;
 205
 206 struct tb_drom_entry_port {
 207         /* BYTES 0-1 */
 208         struct tb_drom_entry_header header;
 209         /* BYTE 2 */
 210         u8 dual_link_port_rid:4;
 211         u8 link_nr:1;
 212         u8 unknown1:2;
 213         bool has_dual_link_port:1;
 214
 215         /* BYTE 3 */
 216         u8 dual_link_port_nr:6;
 217         u8 unknown2:2;
 218
 219         /* BYTES 4 - 5 TODO decode */
 220         u8 micro2:4;
 221         u8 micro1:4;
 222         u8 micro3;
 223
 224         /* BYTES 5-6, TODO: verify (find hardware that has these set) */
 225         u8 peer_port_rid:4;
 226         u8 unknown3:3;
 227         bool has_peer_port:1;
 228         u8 peer_port_nr:6;
 229         u8 unknown4:2;
 230 } __packed;
 231
 232
 233 /**
 234  * tb_eeprom_get_drom_offset - get drom offset within eeprom
 235  */
 236 static int tb_eeprom_get_drom_offset(struct tb_switch *sw, u16 *offset)
 237 {
 238         struct tb_cap_plug_events cap;
 239         int res;
 240         if (!sw->cap_plug_events) {
 241                 tb_sw_warn(sw, "no TB_CAP_PLUG_EVENTS, cannot read eeprom\n");
 242                 return -ENOSYS;
 243         }
 244         res = tb_sw_read(sw, &cap, TB_CFG_SWITCH, sw->cap_plug_events,
 245                              sizeof(cap) / 4);
 246         if (res)
 247                 return res;
 248
 249         if (!cap.eeprom_ctl.present || cap.eeprom_ctl.not_present) {
 250                 tb_sw_warn(sw, "no NVM\n");
 251                 return -ENOSYS;
 252         }
 253
 254         if (cap.drom_offset > 0xffff) {
 255                 tb_sw_warn(sw, "drom offset is larger than 0xffff: %#x\n",
 256                                 cap.drom_offset);
 257                 return -ENXIO;
 258         }
 259         *offset = cap.drom_offset;
 260         return 0;
 261 }
 262
 263 /**
 264  * tb_drom_read_uid_only - read uid directly from drom
 265  *
 266  * Does not use the cached copy in sw->drom. Used during resume to check switch
 267  * identity.
 268  */
 269 int tb_drom_read_uid_only(struct tb_switch *sw, u64 *uid)
 270 {
 271         u8 data[9];
 272         u16 drom_offset;
 273         u8 crc;
 274         int res = tb_eeprom_get_drom_offset(sw, &drom_offset);
 275         if (res)
 276                 return res;
 277
 278         /* read uid */
 279         res = tb_eeprom_read_n(sw, drom_offset, data, 9);
 280         if (res)
 281                 return res;
 282
 283         crc = tb_crc8(data + 1, 8);
 284         if (crc != data[0]) {
 285                 tb_sw_warn(sw, "uid crc8 missmatch (expected: %#x, got: %#x)\n",
 286                                 data[0], crc);
 287                 return -EIO;
 288         }
 289
 290         *uid = *(u64 *)(data+1);
 291         return 0;
 292 }
 293
 294 static void tb_drom_parse_port_entry(struct tb_port *port,
 295                 struct tb_drom_entry_port *entry)
 296 {
 297         port->link_nr = entry->link_nr;
 298         if (entry->has_dual_link_port)
 299                 port->dual_link_port =
 300                                 &port->sw->ports[entry->dual_link_port_nr];
 301 }
 302
 303 static int tb_drom_parse_entry(struct tb_switch *sw,
 304                 struct tb_drom_entry_header *header)
 305 {
 306         struct tb_port *port;
 307         int res;
 308         enum tb_port_type type;
 309
 310         if (header->type != TB_DROM_ENTRY_PORT)
 311                 return 0;
 312
 313         port = &sw->ports[header->index];
 314         port->disabled = header->port_disabled;
 315         if (port->disabled)
 316                 return 0;
 317
 318         res = tb_port_read(port, &type, TB_CFG_PORT, 2, 1);
 319         if (res)
 320                 return res;
 321         type &= 0xffffff;
 322
 323         if (type == TB_TYPE_PORT) {
 324                 struct tb_drom_entry_port *entry = (void *) header;
 325                 if (header->len != sizeof(*entry)) {
 326                         tb_sw_warn(sw,
 327                                 "port entry has size %#x (expected %#zx)\n",
 328                                 header->len, sizeof(struct tb_drom_entry_port));
 329                         return -EIO;
 330                 }
 331                 tb_drom_parse_port_entry(port, entry);
 332         }
 333         return 0;
 334 }
 335
 336 /**
 337  * tb_drom_parse_entries - parse the linked list of drom entries
 338  *
 339  * Drom must have been copied to sw->drom.
 340  */
 341 static int tb_drom_parse_entries(struct tb_switch *sw)
 342 {
 343         struct tb_drom_header *header = (void *) sw->drom;
 344         u16 pos = sizeof(*header);
 345         u16 drom_size = header->data_len + TB_DROM_DATA_START;
 346
 347         while (pos < drom_size) {
 348                 struct tb_drom_entry_header *entry = (void *) (sw->drom + pos);
 349                 if (pos + 1 == drom_size || pos + entry->len > drom_size
 350                                 || !entry->len) {
 351                         tb_sw_warn(sw, "drom buffer overrun, aborting\n");
 352                         return -EIO;
 353                 }
 354
 355                 tb_drom_parse_entry(sw, entry);
 356
 357                 pos += entry->len;
 358         }
 359         return 0;
 360 }
 361
 362 /**
 363  * tb_drom_read - copy drom to sw->drom and parse it
 364  */
 365 int tb_drom_read(struct tb_switch *sw)
 366 {
 367         u16 drom_offset;
 368         u16 size;
 369         u32 crc;
 370         struct tb_drom_header *header;
 371         int res;
 372         if (sw->drom)
 373                 return 0;
 374
 375         if (tb_route(sw) == 0) {
 376                 /*
 377                  * The root switch contains only a dummy drom (header only,
 378                  * no entries). Hardcode the configuration here.
 379                  */
 380                 tb_drom_read_uid_only(sw, &sw->uid);
 381
 382                 sw->ports[1].link_nr = 0;
 383                 sw->ports[2].link_nr = 1;
 384                 sw->ports[1].dual_link_port = &sw->ports[2];
 385                 sw->ports[2].dual_link_port = &sw->ports[1];
 386
 387                 sw->ports[3].link_nr = 0;
 388                 sw->ports[4].link_nr = 1;
 389                 sw->ports[3].dual_link_port = &sw->ports[4];
 390                 sw->ports[4].dual_link_port = &sw->ports[3];
 391                 return 0;
 392         }
 393
 394         res = tb_eeprom_get_drom_offset(sw, &drom_offset);
 395         if (res)
 396                 return res;
 397
 398         res = tb_eeprom_read_n(sw, drom_offset + 14, (u8 *) &size, 2);
 399         if (res)
 400                 return res;
 401         size &= 0x3ff;
 402         size += TB_DROM_DATA_START;
 403         tb_sw_info(sw, "reading drom (length: %#x)\n", size);
 404         if (size < sizeof(*header)) {
 405                 tb_sw_warn(sw, "drom too small, aborting\n");
 406                 return -EIO;
 407         }
 408
 409         sw->drom = kzalloc(size, GFP_KERNEL);
 410         if (!sw->drom)
 411                 return -ENOMEM;
 412         res = tb_eeprom_read_n(sw, drom_offset, sw->drom, size);
 413         if (res)
 414                 goto err;
 415
 416         header = (void *) sw->drom;
 417
 418         if (header->data_len + TB_DROM_DATA_START != size) {
 419                 tb_sw_warn(sw, "drom size mismatch, aborting\n");
 420                 goto err;
 421         }
 422
 423         crc = tb_crc8((u8 *) &header->uid, 8);
 424         if (crc != header->uid_crc8) {
 425                 tb_sw_warn(sw,
 426                         "drom uid crc8 mismatch (expected: %#x, got: %#x), aborting\n",
 427                         header->uid_crc8, crc);
 428                 goto err;
 429         }
 430         sw->uid = header->uid;
 431
 432         crc = tb_crc32(sw->drom + TB_DROM_DATA_START, header->data_len);
 433         if (crc != header->data_crc32) {
 434                 tb_sw_warn(sw,
 435                         "drom data crc32 mismatch (expected: %#x, got: %#x), aborting\n",
 436                         header->data_crc32, crc);
 437                 goto err;
 438         }
 439
 440         if (header->device_rom_revision > 1)
 441                 tb_sw_warn(sw, "drom device_rom_revision %#x unknown\n",
 442                         header->device_rom_revision);
 443
 444         return tb_drom_parse_entries(sw);
 445 err:
 446         kfree(sw->drom);
 447         sw->drom = NULL;
 448         return -EIO;
 449
 450 }