rt2860_io.c

   1
   2 /*-
   3  * Copyright (c) 2009-2010 Alexander Egorenkov <egorenar@gmail.com>
   4  * Copyright (c) 2009 Damien Bergamini <damien.bergamini@free.fr>
   5  *
   6  * Permission to use, copy, modify, and distribute this software for any
   7  * purpose with or without fee is hereby granted, provided that the above
   8  * copyright notice and this permission notice appear in all copies.
   9  *
  10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  17  */
  18
  19 #include "rt2860_io.h"
  20 #include "rt2860_reg.h"
  21
  22 /*
  23  * Defines and macros
  24  */
  25
  26 /*
  27  * RT2860_IO_EEPROM_RAISE_CLK
  28  */
  29 #define RT2860_IO_EEPROM_RAISE_CLK(sc, val)                                                     \
  30 do                                                                                                                                      \
  31 {                                                                                                                                       \
  32         (val) |= RT2860_REG_EESK;                                                                               \
  33                                                                                                                                         \
  34         rt2860_io_mac_write((sc), RT2860_REG_EEPROM_CSR, (val));                \
  35                                                                                                                                         \
  36         DELAY(1);                                                                                                               \
  37 } while (0)
  38
  39 /*
  40  * RT2860_IO_EEPROM_LOWER_CLK
  41  */
  42 #define RT2860_IO_EEPROM_LOWER_CLK(sc, val)                                                     \
  43 do                                                                                                                                      \
  44 {                                                                                                                                       \
  45         (val) &= ~RT2860_REG_EESK;                                                                              \
  46                                                                                                                                         \
  47         rt2860_io_mac_write((sc), RT2860_REG_EEPROM_CSR, (val));                \
  48                                                                                                                                         \
  49         DELAY(1);                                                                                                               \
  50 } while (0)
  51
  52 #define RT2860_IO_BYTE_CRC16(byte, crc)                                                         \
  53         ((uint16_t) (((crc) << 8) ^ rt2860_io_ccitt16[(((crc) >> 8) ^ (byte)) & 255]))
  54
  55 /*
  56  * Static function prototypes
  57  */
  58
  59 static void rt2860_io_eeprom_shiftout_bits(struct rt2860_softc *sc,
  60         uint16_t val, uint16_t count);
  61
  62 static uint16_t rt2860_io_eeprom_shiftin_bits(struct rt2860_softc *sc);
  63
  64 static uint8_t rt2860_io_byte_rev(uint8_t byte);
  65
  66 /*
  67  * Static variables
  68  */
  69
  70 static const uint16_t rt2860_io_ccitt16[] =
  71 {
  72         0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7,
  73         0x8108, 0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef,
  74         0x1231, 0x0210, 0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6,
  75         0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c, 0xf3ff, 0xe3de,
  76         0x2462, 0x3443, 0x0420, 0x1401, 0x64e6, 0x74c7, 0x44a4, 0x5485,
  77         0xa56a, 0xb54b, 0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d,
  78         0x3653, 0x2672, 0x1611, 0x0630, 0x76d7, 0x66f6, 0x5695, 0x46b4,
  79         0xb75b, 0xa77a, 0x9719, 0x8738, 0xf7df, 0xe7fe, 0xd79d, 0xc7bc,
  80         0x48c4, 0x58e5, 0x6886, 0x78a7, 0x0840, 0x1861, 0x2802, 0x3823,
  81         0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969, 0xa90a, 0xb92b,
  82         0x5af5, 0x4ad4, 0x7ab7, 0x6a96, 0x1a71, 0x0a50, 0x3a33, 0x2a12,
  83         0xdbfd, 0xcbdc, 0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a,
  84         0x6ca6, 0x7c87, 0x4ce4, 0x5cc5, 0x2c22, 0x3c03, 0x0c60, 0x1c41,
  85         0xedae, 0xfd8f, 0xcdec, 0xddcd, 0xad2a, 0xbd0b, 0x8d68, 0x9d49,
  86         0x7e97, 0x6eb6, 0x5ed5, 0x4ef4, 0x3e13, 0x2e32, 0x1e51, 0x0e70,
  87         0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a, 0x9f59, 0x8f78,
  88         0x9188, 0x81a9, 0xb1ca, 0xa1eb, 0xd10c, 0xc12d, 0xf14e, 0xe16f,
  89         0x1080, 0x00a1, 0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067,
  90         0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c, 0xe37f, 0xf35e,
  91         0x02b1, 0x1290, 0x22f3, 0x32d2, 0x4235, 0x5214, 0x6277, 0x7256,
  92         0xb5ea, 0xa5cb, 0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d,
  93         0x34e2, 0x24c3, 0x14a0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405,
  94         0xa7db, 0xb7fa, 0x8799, 0x97b8, 0xe75f, 0xf77e, 0xc71d, 0xd73c,
  95         0x26d3, 0x36f2, 0x0691, 0x16b0, 0x6657, 0x7676, 0x4615, 0x5634,
  96         0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9, 0xb98a, 0xa9ab,
  97         0x5844, 0x4865, 0x7806, 0x6827, 0x18c0, 0x08e1, 0x3882, 0x28a3,
  98         0xcb7d, 0xdb5c, 0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a,
  99         0x4a75, 0x5a54, 0x6a37, 0x7a16, 0x0af1, 0x1ad0, 0x2ab3, 0x3a92,
 100         0xfd2e, 0xed0f, 0xdd6c, 0xcd4d, 0xbdaa, 0xad8b, 0x9de8, 0x8dc9,
 101         0x7c26, 0x6c07, 0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0x0cc1,
 102         0xef1f, 0xff3e, 0xcf5d, 0xdf7c, 0xaf9b, 0xbfba, 0x8fd9, 0x9ff8,
 103         0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0x0ed1, 0x1ef0
 104 };
 105
 106 /*
 107  * rt2860_io_mac_read
 108  */
 109 uint32_t rt2860_io_mac_read(struct rt2860_softc *sc, uint16_t reg)
 110 {
 111         return bus_space_read_4(sc->bst, sc->bsh, reg);
 112 }
 113
 114 /*
 115  * rt2860_io_mac_read_multi
 116  */
 117 void rt2860_io_mac_read_multi(struct rt2860_softc *sc,
 118         uint16_t reg, void *buf, size_t len)
 119 {
 120         bus_space_read_region_1(sc->bst, sc->bsh, reg, buf, len);
 121 }
 122
 123 /*
 124  * rt2860_io_mac_write
 125  */
 126 void rt2860_io_mac_write(struct rt2860_softc *sc,
 127         uint16_t reg, uint32_t val)
 128 {
 129         bus_space_write_4(sc->bst, sc->bsh, reg, val);
 130 }
 131
 132 /*
 133  * rt2860_io_mac_write_multi
 134  */
 135 void rt2860_io_mac_write_multi(struct rt2860_softc *sc,
 136         uint16_t reg, const void *buf, size_t len)
 137 {
 138         bus_space_write_region_1(sc->bst, sc->bsh, reg, buf, len);
 139 }
 140
 141 /*
 142  * rt2860_io_mac_set_region_4
 143  */
 144 void rt2860_io_mac_set_region_4(struct rt2860_softc *sc,
 145         uint16_t reg, uint32_t val, size_t len)
 146 {
 147         int i;
 148
 149         for (i = 0; i < len; i += sizeof(uint32_t))
 150                 rt2860_io_mac_write(sc, reg + i, val);
 151 }
 152
 153 /*
 154  * rt2860_io_eeprom_read
 155  */
 156 uint16_t rt2860_io_eeprom_read(struct rt2860_softc *sc, uint16_t addr)
 157 {
 158         uint32_t tmp;
 159         uint16_t val;
 160
 161         addr = (addr >> 1);
 162
 163         tmp = rt2860_io_mac_read(sc, RT2860_REG_EEPROM_CSR);
 164
 165         tmp &= ~(RT2860_REG_EEDI | RT2860_REG_EEDO | RT2860_REG_EESK);
 166         tmp |= RT2860_REG_EECS;
 167
 168         rt2860_io_mac_write(sc, RT2860_REG_EEPROM_CSR, tmp);
 169
 170         if (((sc->mac_rev & 0xffff0000) != 0x30710000) &&
 171                 ((sc->mac_rev & 0xffff0000) != 0x30900000) &&
 172                 ((sc->mac_rev & 0xffff0000) != 0x35720000) &&
 173                 ((sc->mac_rev & 0xffff0000) != 0x33900000))
 174         {
 175                 RT2860_IO_EEPROM_RAISE_CLK(sc, tmp);
 176                 RT2860_IO_EEPROM_LOWER_CLK(sc, tmp);
 177         }
 178
 179         rt2860_io_eeprom_shiftout_bits(sc, RT2860_REG_EEOP_READ, 3);
 180         rt2860_io_eeprom_shiftout_bits(sc, addr, sc->eeprom_addr_num);
 181
 182         val = rt2860_io_eeprom_shiftin_bits(sc);
 183
 184         tmp = rt2860_io_mac_read(sc, RT2860_REG_EEPROM_CSR);
 185
 186         tmp &= ~(RT2860_REG_EECS | RT2860_REG_EEDI);
 187
 188         rt2860_io_mac_write(sc, RT2860_REG_EEPROM_CSR, tmp);
 189
 190         RT2860_IO_EEPROM_RAISE_CLK(sc, tmp);
 191         RT2860_IO_EEPROM_LOWER_CLK(sc, tmp);
 192
 193         return val;
 194 }
 195
 196 /*
 197  * rt2860_io_eeprom_read_multi
 198  */
 199 void rt2860_io_eeprom_read_multi(struct rt2860_softc *sc,
 200         uint16_t addr, void *buf, size_t len)
 201 {
 202         uint16_t *ptr;
 203         int i;
 204
 205         len += len % sizeof(uint16_t);
 206         ptr = buf;
 207
 208         i = 0;
 209
 210         do
 211         {
 212                 *ptr++ = rt2860_io_eeprom_read(sc, addr + i);
 213
 214                 i += sizeof(uint16_t);
 215                 len -= sizeof(uint16_t);
 216         } while (len > 0);
 217 }
 218
 219 /*
 220  * rt2860_io_bbp_read
 221  */
 222 uint8_t rt2860_io_bbp_read(struct rt2860_softc *sc, uint8_t reg)
 223 {
 224         int ntries;
 225         uint32_t tmp;
 226
 227         for (ntries = 0; ntries < 100; ntries++)
 228         {
 229                 if (!(rt2860_io_mac_read(sc, RT2860_REG_H2M_MAILBOX_BBP_AGENT) &
 230                         RT2860_REG_BBP_CSR_BUSY))
 231                         break;
 232
 233                 DELAY(1);
 234         }
 235
 236         if (ntries == 100)
 237         {
 238                 printf("%s: could not read from BBP through MCU\n",
 239                         device_get_nameunit(sc->dev));
 240                 return 0;
 241         }
 242
 243         tmp = RT2860_REG_BBP_RW_MODE_PARALLEL |
 244                 RT2860_REG_BBP_CSR_BUSY |
 245                 RT2860_REG_BBP_CSR_READ |
 246                 ((reg & RT2860_REG_BBP_REG_MASK) << RT2860_REG_BBP_REG_SHIFT);
 247
 248         rt2860_io_mac_write(sc, RT2860_REG_H2M_MAILBOX_BBP_AGENT, tmp);
 249
 250         rt2860_io_mcu_cmd(sc, RT2860_IO_MCU_CMD_BBP,
 251                 RT2860_REG_H2M_TOKEN_NO_INTR, 0);
 252
 253         DELAY(1000);
 254
 255         for (ntries = 0; ntries < 100; ntries++)
 256         {
 257                 tmp = rt2860_io_mac_read(sc, RT2860_REG_H2M_MAILBOX_BBP_AGENT);
 258                 if (!(tmp & RT2860_REG_BBP_CSR_BUSY))
 259                         return ((tmp >> RT2860_REG_BBP_VAL_SHIFT) &
 260                                 RT2860_REG_BBP_VAL_MASK);
 261
 262                 DELAY(1);
 263         }
 264
 265         printf("%s: could not read from BBP through MCU\n",
 266                 device_get_nameunit(sc->dev));
 267
 268         return 0;
 269 }
 270
 271 /*
 272  * rt2860_io_bbp_write
 273  */
 274 void rt2860_io_bbp_write(struct rt2860_softc *sc, uint8_t reg, uint8_t val)
 275 {
 276         int ntries;
 277         uint32_t tmp;
 278
 279         for (ntries = 0; ntries < 100; ntries++)
 280         {
 281                 if (!(rt2860_io_mac_read(sc, RT2860_REG_H2M_MAILBOX_BBP_AGENT) &
 282                         RT2860_REG_BBP_CSR_BUSY))
 283                         break;
 284
 285                 DELAY(1);
 286         }
 287
 288         if (ntries == 100)
 289         {
 290                 printf("%s: could not write to BBP through MCU\n",
 291                         device_get_nameunit(sc->dev));
 292                 return;
 293         }
 294
 295         tmp = RT2860_REG_BBP_RW_MODE_PARALLEL |
 296                 RT2860_REG_BBP_CSR_BUSY |
 297                 ((reg & RT2860_REG_BBP_REG_MASK) << RT2860_REG_BBP_REG_SHIFT) |
 298                 ((val & RT2860_REG_BBP_VAL_MASK) << RT2860_REG_BBP_VAL_SHIFT);
 299
 300         rt2860_io_mac_write(sc, RT2860_REG_H2M_MAILBOX_BBP_AGENT, tmp);
 301
 302         rt2860_io_mcu_cmd(sc, RT2860_IO_MCU_CMD_BBP,
 303                 RT2860_REG_H2M_TOKEN_NO_INTR, 0);
 304
 305         DELAY(1000);
 306 }
 307
 308 /*
 309  * rt2860_io_rf_write
 310  */
 311 void rt2860_io_rf_write(struct rt2860_softc *sc, uint8_t reg, uint32_t val)
 312 {
 313         int ntries;
 314
 315         for (ntries = 0; ntries < 100; ntries++)
 316                 if (!(rt2860_io_mac_read(sc, RT2860_REG_RF_CSR_CFG0) &
 317                         RT2860_REG_RF_BUSY))
 318                         break;
 319
 320         if (ntries == 100)
 321         {
 322                 printf("%s: could not write to RF\n",
 323                         device_get_nameunit(sc->dev));
 324                 return;
 325         }
 326
 327         rt2860_io_mac_write(sc, RT2860_REG_RF_CSR_CFG0, val);
 328 }
 329
 330 /*
 331  * rt2860_io_mcu_cmd
 332  */
 333 void rt2860_io_mcu_cmd(struct rt2860_softc *sc, uint8_t cmd,
 334         uint8_t token, uint16_t arg)
 335 {
 336         uint32_t tmp;
 337         int ntries;
 338
 339         for (ntries = 0; ntries < 100; ntries++)
 340         {
 341                 if (!(rt2860_io_mac_read(sc, RT2860_REG_H2M_MAILBOX) &
 342                         RT2860_REG_H2M_BUSY))
 343                         break;
 344
 345                 DELAY(2);
 346         }
 347
 348         if (ntries == 100)
 349         {
 350                 printf("%s: could not read H2M\n",
 351                         device_get_nameunit(sc->dev));
 352                 return;
 353         }
 354
 355         tmp = RT2860_REG_H2M_BUSY | (token << 16) | arg;
 356
 357         rt2860_io_mac_write(sc, RT2860_REG_H2M_MAILBOX, tmp);
 358         rt2860_io_mac_write(sc, RT2860_REG_H2M_HOST_CMD, cmd);
 359 }
 360
 361 /*
 362  * rt2860_io_mcu_cmd_check
 363  */
 364 int rt2860_io_mcu_cmd_check(struct rt2860_softc *sc, uint8_t cid)
 365 {
 366         uint32_t tmp, mask, status;
 367         int result, ntries;
 368
 369         result = -1;
 370
 371         for (ntries = 0; ntries < 200; ntries++)
 372         {
 373                 tmp = rt2860_io_mac_read(sc, RT2860_REG_H2M_MAILBOX_CID);
 374
 375                 if (((cid >> RT2860_REG_H2M_CID0_SHIFT) & RT2860_REG_H2M_CID_MASK) == cid)
 376                 {
 377                         mask = (RT2860_REG_H2M_CID_MASK << RT2860_REG_H2M_CID0_SHIFT);
 378                         break;
 379                 }
 380                 else if (((tmp >> RT2860_REG_H2M_CID1_SHIFT) & RT2860_REG_H2M_CID_MASK) == cid)
 381                 {
 382                         mask = (RT2860_REG_H2M_CID_MASK << RT2860_REG_H2M_CID1_SHIFT);
 383                         break;
 384                 }
 385                 else if (((tmp >> RT2860_REG_H2M_CID2_SHIFT) & RT2860_REG_H2M_CID_MASK) == cid)
 386                 {
 387                         mask = (RT2860_REG_H2M_CID_MASK << RT2860_REG_H2M_CID2_SHIFT);
 388                         break;
 389                 }
 390                 else if (((tmp >> RT2860_REG_H2M_CID3_SHIFT) & RT2860_REG_H2M_CID_MASK) == cid)
 391                 {
 392                         mask = (RT2860_REG_H2M_CID_MASK << RT2860_REG_H2M_CID3_SHIFT);
 393                         break;
 394                 }
 395
 396                 DELAY(100);
 397         }
 398
 399         status = rt2860_io_mac_read(sc, RT2860_REG_H2M_MAILBOX_STATUS);
 400
 401         if (ntries < 200)
 402         {
 403                 status &= mask;
 404
 405                 if ((status == 0x1) ||
 406                         (status == 0x100) ||
 407                         (status == 0x10000) ||
 408                         (status == 0x1000000))
 409                         result = 0;
 410         }
 411
 412         rt2860_io_mac_write(sc, RT2860_REG_H2M_MAILBOX_STATUS, 0xffffffff);
 413         rt2860_io_mac_write(sc, RT2860_REG_H2M_MAILBOX_CID, 0xffffffff);
 414
 415         return result;
 416 }
 417
 418 /*
 419  * rt2860_io_mcu_load_ucode
 420  */
 421 int rt2860_io_mcu_load_ucode(struct rt2860_softc *sc,
 422         const uint8_t *ucode, size_t len)
 423 {
 424         int i, ntries;
 425         uint16_t crc;
 426
 427         for (i = 0, crc = 0xffff; i < len - 2; i++)
 428                 crc = RT2860_IO_BYTE_CRC16(rt2860_io_byte_rev(ucode[i]), crc);
 429
 430         if (ucode[len - 2] != rt2860_io_byte_rev(crc >> 8) ||
 431                 ucode[len - 1] != rt2860_io_byte_rev(crc))
 432         {
 433                 printf("%s: wrong microcode crc\n",
 434                         device_get_nameunit(sc->dev));
 435                 return EINVAL;
 436         }
 437
 438         rt2860_io_mac_write(sc, RT2860_REG_PBF_SYS_CTRL, RT2860_REG_HST_PM_SEL);
 439
 440         rt2860_io_mac_write_multi(sc, RT2860_REG_MCU_UCODE_BASE, ucode, len);
 441
 442         rt2860_io_mac_write(sc, RT2860_REG_PBF_SYS_CTRL, 0);
 443         rt2860_io_mac_write(sc, RT2860_REG_PBF_SYS_CTRL, RT2860_REG_MCU_RESET);
 444
 445         /* initialize BBP R/W access agent */
 446
 447         rt2860_io_mac_write(sc, RT2860_REG_H2M_MAILBOX_BBP_AGENT, 0);
 448         rt2860_io_mac_write(sc, RT2860_REG_H2M_MAILBOX, 0);
 449
 450         for (ntries = 0; ntries < 1000; ntries++)
 451         {
 452                 if (rt2860_io_mac_read(sc, RT2860_REG_PBF_SYS_CTRL) &
 453                         RT2860_REG_MCU_READY)
 454                         break;
 455
 456                 DELAY(1000);
 457         }
 458
 459         if (ntries == 1000)
 460         {
 461                 printf("%s: timeout waiting for MCU to initialize\n",
 462                         device_get_nameunit(sc->dev));
 463                 return ETIMEDOUT;
 464         }
 465
 466         return 0;
 467 }
 468
 469 /*
 470  * rt2860_io_eeprom_shiftout_bits
 471  */
 472 static void rt2860_io_eeprom_shiftout_bits(struct rt2860_softc *sc,
 473         uint16_t val, uint16_t count)
 474 {
 475         uint32_t mask, tmp;
 476
 477         mask = (1 << (count - 1));
 478
 479         tmp = rt2860_io_mac_read(sc, RT2860_REG_EEPROM_CSR);
 480
 481         tmp &= ~(RT2860_REG_EEDO | RT2860_REG_EEDI);
 482
 483         do
 484         {
 485             tmp &= ~RT2860_REG_EEDI;
 486
 487             if(val & mask)
 488                         tmp |= RT2860_REG_EEDI;
 489
 490                 rt2860_io_mac_write(sc, RT2860_REG_EEPROM_CSR, tmp);
 491
 492                 RT2860_IO_EEPROM_RAISE_CLK(sc, tmp);
 493                 RT2860_IO_EEPROM_LOWER_CLK(sc, tmp);
 494
 495             mask = (mask >> 1);
 496         } while (mask);
 497
 498         tmp &= ~RT2860_REG_EEDI;
 499
 500         rt2860_io_mac_write(sc, RT2860_REG_EEPROM_CSR, tmp);
 501 }
 502
 503 /*
 504  * rt2860_io_eeprom_shiftin_bits
 505  */
 506 static uint16_t rt2860_io_eeprom_shiftin_bits(struct rt2860_softc *sc)
 507 {
 508         uint32_t tmp;
 509         uint16_t val;
 510         int i;
 511
 512         val = 0;
 513
 514         tmp = rt2860_io_mac_read(sc, RT2860_REG_EEPROM_CSR);
 515
 516         tmp &= ~(RT2860_REG_EEDO | RT2860_REG_EEDI);
 517
 518         for(i = 0; i < 16; i++)
 519         {
 520                 val = (val << 1);
 521
 522                 RT2860_IO_EEPROM_RAISE_CLK(sc, tmp);
 523
 524                 tmp = rt2860_io_mac_read(sc, RT2860_REG_EEPROM_CSR);
 525
 526                 RT2860_IO_EEPROM_LOWER_CLK(sc, tmp);
 527
 528                 tmp &= ~RT2860_REG_EEDI;
 529                 if(tmp & RT2860_REG_EEDO)
 530                     val |= 1;
 531         }
 532
 533         return val;
 534 }
 535
 536 /*
 537  * rt2860_io_byte_rev
 538  */
 539 static uint8_t rt2860_io_byte_rev(uint8_t byte)
 540 {
 541         int i;
 542         uint8_t tmp;
 543
 544         for(i = 0, tmp = 0; ; i++)
 545         {
 546                 if(byte & 0x80)
 547                         tmp |= 0x80;
 548
 549                 if(i == 7)
 550                         break;
 551
 552                 byte <<= 1;
 553                 tmp >>= 1;
 554         }
 555
 556         return tmp;
 557 }