kernel/drivers/char/ipmi/ipmi_bt_sm.c

   1 /*
   2  *  ipmi_bt_sm.c
   3  *
   4  *  The state machine for an Open IPMI BT sub-driver under ipmi_si.c, part
   5  *  of the driver architecture at http://sourceforge.net/projects/openipmi
   6  *
   7  *  Author:     Rocky Craig <first.last@hp.com>
   8  *
   9  *  This program is free software; you can redistribute it and/or modify it
  10  *  under the terms of the GNU General Public License as published by the
  11  *  Free Software Foundation; either version 2 of the License, or (at your
  12  *  option) any later version.
  13  *
  14  *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
  15  *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  16  *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  17  *  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  18  *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
  19  *  BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
  20  *  OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  21  *  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
  22  *  TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
  23  *  USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  *
  25  *  You should have received a copy of the GNU General Public License along
  26  *  with this program; if not, write to the Free Software Foundation, Inc.,
  27  *  675 Mass Ave, Cambridge, MA 02139, USA.  */
  28
  29 #include <linux/kernel.h> /* For printk. */
  30 #include <linux/string.h>
  31 #include <linux/module.h>
  32 #include <linux/moduleparam.h>
  33 #include <linux/ipmi_msgdefs.h>         /* for completion codes */
  34 #include "ipmi_si_sm.h"
  35
  36 #define BT_DEBUG_OFF    0       /* Used in production */
  37 #define BT_DEBUG_ENABLE 1       /* Generic messages */
  38 #define BT_DEBUG_MSG    2       /* Prints all request/response buffers */
  39 #define BT_DEBUG_STATES 4       /* Verbose look at state changes */
  40 /*
  41  * BT_DEBUG_OFF must be zero to correspond to the default uninitialized
  42  * value
  43  */
  44
  45 static int bt_debug; /* 0 == BT_DEBUG_OFF */
  46
  47 module_param(bt_debug, int, 0644);
  48 MODULE_PARM_DESC(bt_debug, "debug bitmask, 1=enable, 2=messages, 4=states");
  49
  50 /*
  51  * Typical "Get BT Capabilities" values are 2-3 retries, 5-10 seconds,
  52  * and 64 byte buffers.  However, one HP implementation wants 255 bytes of
  53  * buffer (with a documented message of 160 bytes) so go for the max.
  54  * Since the Open IPMI architecture is single-message oriented at this
  55  * stage, the queue depth of BT is of no concern.
  56  */
  57
  58 #define BT_NORMAL_TIMEOUT       5       /* seconds */
  59 #define BT_NORMAL_RETRY_LIMIT   2
  60 #define BT_RESET_DELAY          6       /* seconds after warm reset */
  61
  62 /*
  63  * States are written in chronological order and usually cover
  64  * multiple rows of the state table discussion in the IPMI spec.
  65  */
  66
  67 enum bt_states {
  68         BT_STATE_IDLE = 0,      /* Order is critical in this list */
  69         BT_STATE_XACTION_START,
  70         BT_STATE_WRITE_BYTES,
  71         BT_STATE_WRITE_CONSUME,
  72         BT_STATE_READ_WAIT,
  73         BT_STATE_CLEAR_B2H,
  74         BT_STATE_READ_BYTES,
  75         BT_STATE_RESET1,        /* These must come last */
  76         BT_STATE_RESET2,
  77         BT_STATE_RESET3,
  78         BT_STATE_RESTART,
  79         BT_STATE_PRINTME,
  80         BT_STATE_CAPABILITIES_BEGIN,
  81         BT_STATE_CAPABILITIES_END,
  82         BT_STATE_LONG_BUSY      /* BT doesn't get hosed :-) */
  83 };
  84
  85 /*
  86  * Macros seen at the end of state "case" blocks.  They help with legibility
  87  * and debugging.
  88  */
  89
  90 #define BT_STATE_CHANGE(X, Y) { bt->state = X; return Y; }
  91
  92 #define BT_SI_SM_RETURN(Y)   { last_printed = BT_STATE_PRINTME; return Y; }
  93
  94 struct si_sm_data {
  95         enum bt_states  state;
  96         unsigned char   seq;            /* BT sequence number */
  97         struct si_sm_io *io;
  98         unsigned char   write_data[IPMI_MAX_MSG_LENGTH + 2]; /* +2 for memcpy */
  99         int             write_count;
 100         unsigned char   read_data[IPMI_MAX_MSG_LENGTH + 2]; /* +2 for memcpy */
 101         int             read_count;
 102         int             truncated;
 103         long            timeout;        /* microseconds countdown */
 104         int             error_retries;  /* end of "common" fields */
 105         int             nonzero_status; /* hung BMCs stay all 0 */
 106         enum bt_states  complete;       /* to divert the state machine */
 107         int             BT_CAP_outreqs;
 108         long            BT_CAP_req2rsp;
 109         int             BT_CAP_retries; /* Recommended retries */
 110 };
 111
 112 #define BT_CLR_WR_PTR   0x01    /* See IPMI 1.5 table 11.6.4 */
 113 #define BT_CLR_RD_PTR   0x02
 114 #define BT_H2B_ATN      0x04
 115 #define BT_B2H_ATN      0x08
 116 #define BT_SMS_ATN      0x10
 117 #define BT_OEM0         0x20
 118 #define BT_H_BUSY       0x40
 119 #define BT_B_BUSY       0x80
 120
 121 /*
 122  * Some bits are toggled on each write: write once to set it, once
 123  * more to clear it; writing a zero does nothing.  To absolutely
 124  * clear it, check its state and write if set.  This avoids the "get
 125  * current then use as mask" scheme to modify one bit.  Note that the
 126  * variable "bt" is hardcoded into these macros.
 127  */
 128
 129 #define BT_STATUS       bt->io->inputb(bt->io, 0)
 130 #define BT_CONTROL(x)   bt->io->outputb(bt->io, 0, x)
 131
 132 #define BMC2HOST        bt->io->inputb(bt->io, 1)
 133 #define HOST2BMC(x)     bt->io->outputb(bt->io, 1, x)
 134
 135 #define BT_INTMASK_R    bt->io->inputb(bt->io, 2)
 136 #define BT_INTMASK_W(x) bt->io->outputb(bt->io, 2, x)
 137
 138 /*
 139  * Convenience routines for debugging.  These are not multi-open safe!
 140  * Note the macros have hardcoded variables in them.
 141  */
 142
 143 static char *state2txt(unsigned char state)
 144 {
 145         switch (state) {
 146         case BT_STATE_IDLE:             return("IDLE");
 147         case BT_STATE_XACTION_START:    return("XACTION");
 148         case BT_STATE_WRITE_BYTES:      return("WR_BYTES");
 149         case BT_STATE_WRITE_CONSUME:    return("WR_CONSUME");
 150         case BT_STATE_READ_WAIT:        return("RD_WAIT");
 151         case BT_STATE_CLEAR_B2H:        return("CLEAR_B2H");
 152         case BT_STATE_READ_BYTES:       return("RD_BYTES");
 153         case BT_STATE_RESET1:           return("RESET1");
 154         case BT_STATE_RESET2:           return("RESET2");
 155         case BT_STATE_RESET3:           return("RESET3");
 156         case BT_STATE_RESTART:          return("RESTART");
 157         case BT_STATE_LONG_BUSY:        return("LONG_BUSY");
 158         case BT_STATE_CAPABILITIES_BEGIN: return("CAP_BEGIN");
 159         case BT_STATE_CAPABILITIES_END: return("CAP_END");
 160         }
 161         return("BAD STATE");
 162 }
 163 #define STATE2TXT state2txt(bt->state)
 164
 165 static char *status2txt(unsigned char status)
 166 {
 167         /*
 168          * This cannot be called by two threads at the same time and
 169          * the buffer is always consumed immediately, so the static is
 170          * safe to use.
 171          */
 172         static char buf[40];
 173
 174         strcpy(buf, "[ ");
 175         if (status & BT_B_BUSY)
 176                 strcat(buf, "B_BUSY ");
 177         if (status & BT_H_BUSY)
 178                 strcat(buf, "H_BUSY ");
 179         if (status & BT_OEM0)
 180                 strcat(buf, "OEM0 ");
 181         if (status & BT_SMS_ATN)
 182                 strcat(buf, "SMS ");
 183         if (status & BT_B2H_ATN)
 184                 strcat(buf, "B2H ");
 185         if (status & BT_H2B_ATN)
 186                 strcat(buf, "H2B ");
 187         strcat(buf, "]");
 188         return buf;
 189 }
 190 #define STATUS2TXT status2txt(status)
 191
 192 /* called externally at insmod time, and internally on cleanup */
 193
 194 static unsigned int bt_init_data(struct si_sm_data *bt, struct si_sm_io *io)
 195 {
 196         memset(bt, 0, sizeof(struct si_sm_data));
 197         if (bt->io != io) {
 198                 /* external: one-time only things */
 199                 bt->io = io;
 200                 bt->seq = 0;
 201         }
 202         bt->state = BT_STATE_IDLE;      /* start here */
 203         bt->complete = BT_STATE_IDLE;   /* end here */
 204         bt->BT_CAP_req2rsp = BT_NORMAL_TIMEOUT * USEC_PER_SEC;
 205         bt->BT_CAP_retries = BT_NORMAL_RETRY_LIMIT;
 206         /* BT_CAP_outreqs == zero is a flag to read BT Capabilities */
 207         return 3; /* We claim 3 bytes of space; ought to check SPMI table */
 208 }
 209
 210 /* Jam a completion code (probably an error) into a response */
 211
 212 static void force_result(struct si_sm_data *bt, unsigned char completion_code)
 213 {
 214         bt->read_data[0] = 4;                           /* # following bytes */
 215         bt->read_data[1] = bt->write_data[1] | 4;       /* Odd NetFn/LUN */
 216         bt->read_data[2] = bt->write_data[2];           /* seq (ignored) */
 217         bt->read_data[3] = bt->write_data[3];           /* Command */
 218         bt->read_data[4] = completion_code;
 219         bt->read_count = 5;
 220 }
 221
 222 /* The upper state machine starts here */
 223
 224 static int bt_start_transaction(struct si_sm_data *bt,
 225                                 unsigned char *data,
 226                                 unsigned int size)
 227 {
 228         unsigned int i;
 229
 230         if (size < 2)
 231                 return IPMI_REQ_LEN_INVALID_ERR;
 232         if (size > IPMI_MAX_MSG_LENGTH)
 233                 return IPMI_REQ_LEN_EXCEEDED_ERR;
 234
 235         if (bt->state == BT_STATE_LONG_BUSY)
 236                 return IPMI_NODE_BUSY_ERR;
 237
 238         if (bt->state != BT_STATE_IDLE)
 239                 return IPMI_NOT_IN_MY_STATE_ERR;
 240
 241         if (bt_debug & BT_DEBUG_MSG) {
 242                 printk(KERN_WARNING "BT: +++++++++++++++++ New command\n");
 243                 printk(KERN_WARNING "BT: NetFn/LUN CMD [%d data]:", size - 2);
 244                 for (i = 0; i < size; i ++)
 245                         printk(" %02x", data[i]);
 246                 printk("\n");
 247         }
 248         bt->write_data[0] = size + 1;   /* all data plus seq byte */
 249         bt->write_data[1] = *data;      /* NetFn/LUN */
 250         bt->write_data[2] = bt->seq++;
 251         memcpy(bt->write_data + 3, data + 1, size - 1);
 252         bt->write_count = size + 2;
 253         bt->error_retries = 0;
 254         bt->nonzero_status = 0;
 255         bt->truncated = 0;
 256         bt->state = BT_STATE_XACTION_START;
 257         bt->timeout = bt->BT_CAP_req2rsp;
 258         force_result(bt, IPMI_ERR_UNSPECIFIED);
 259         return 0;
 260 }
 261
 262 /*
 263  * After the upper state machine has been told SI_SM_TRANSACTION_COMPLETE
 264  * it calls this.  Strip out the length and seq bytes.
 265  */
 266
 267 static int bt_get_result(struct si_sm_data *bt,
 268                          unsigned char *data,
 269                          unsigned int length)
 270 {
 271         int i, msg_len;
 272
 273         msg_len = bt->read_count - 2;           /* account for length & seq */
 274         if (msg_len < 3 || msg_len > IPMI_MAX_MSG_LENGTH) {
 275                 force_result(bt, IPMI_ERR_UNSPECIFIED);
 276                 msg_len = 3;
 277         }
 278         data[0] = bt->read_data[1];
 279         data[1] = bt->read_data[3];
 280         if (length < msg_len || bt->truncated) {
 281                 data[2] = IPMI_ERR_MSG_TRUNCATED;
 282                 msg_len = 3;
 283         } else
 284                 memcpy(data + 2, bt->read_data + 4, msg_len - 2);
 285
 286         if (bt_debug & BT_DEBUG_MSG) {
 287                 printk(KERN_WARNING "BT: result %d bytes:", msg_len);
 288                 for (i = 0; i < msg_len; i++)
 289                         printk(" %02x", data[i]);
 290                 printk("\n");
 291         }
 292         return msg_len;
 293 }
 294
 295 /* This bit's functionality is optional */
 296 #define BT_BMC_HWRST    0x80
 297
 298 static void reset_flags(struct si_sm_data *bt)
 299 {
 300         if (bt_debug)
 301                 printk(KERN_WARNING "IPMI BT: flag reset %s\n",
 302                                         status2txt(BT_STATUS));
 303         if (BT_STATUS & BT_H_BUSY)
 304                 BT_CONTROL(BT_H_BUSY);  /* force clear */
 305         BT_CONTROL(BT_CLR_WR_PTR);      /* always reset */
 306         BT_CONTROL(BT_SMS_ATN);         /* always clear */
 307         BT_INTMASK_W(BT_BMC_HWRST);
 308 }
 309
 310 /*
 311  * Get rid of an unwanted/stale response.  This should only be needed for
 312  * BMCs that support multiple outstanding requests.
 313  */
 314
 315 static void drain_BMC2HOST(struct si_sm_data *bt)
 316 {
 317         int i, size;
 318
 319         if (!(BT_STATUS & BT_B2H_ATN))  /* Not signalling a response */
 320                 return;
 321
 322         BT_CONTROL(BT_H_BUSY);          /* now set */
 323         BT_CONTROL(BT_B2H_ATN);         /* always clear */
 324         BT_STATUS;                      /* pause */
 325         BT_CONTROL(BT_B2H_ATN);         /* some BMCs are stubborn */
 326         BT_CONTROL(BT_CLR_RD_PTR);      /* always reset */
 327         if (bt_debug)
 328                 printk(KERN_WARNING "IPMI BT: stale response %s; ",
 329                         status2txt(BT_STATUS));
 330         size = BMC2HOST;
 331         for (i = 0; i < size ; i++)
 332                 BMC2HOST;
 333         BT_CONTROL(BT_H_BUSY);          /* now clear */
 334         if (bt_debug)
 335                 printk("drained %d bytes\n", size + 1);
 336 }
 337
 338 static inline void write_all_bytes(struct si_sm_data *bt)
 339 {
 340         int i;
 341
 342         if (bt_debug & BT_DEBUG_MSG) {
 343                 printk(KERN_WARNING "BT: write %d bytes seq=0x%02X",
 344                         bt->write_count, bt->seq);
 345                 for (i = 0; i < bt->write_count; i++)
 346                         printk(" %02x", bt->write_data[i]);
 347                 printk("\n");
 348         }
 349         for (i = 0; i < bt->write_count; i++)
 350                 HOST2BMC(bt->write_data[i]);
 351 }
 352
 353 static inline int read_all_bytes(struct si_sm_data *bt)
 354 {
 355         unsigned int i;
 356
 357         /*
 358          * length is "framing info", minimum = 4: NetFn, Seq, Cmd, cCode.
 359          * Keep layout of first four bytes aligned with write_data[]
 360          */
 361
 362         bt->read_data[0] = BMC2HOST;
 363         bt->read_count = bt->read_data[0];
 364
 365         if (bt->read_count < 4 || bt->read_count >= IPMI_MAX_MSG_LENGTH) {
 366                 if (bt_debug & BT_DEBUG_MSG)
 367                         printk(KERN_WARNING "BT: bad raw rsp len=%d\n",
 368                                 bt->read_count);
 369                 bt->truncated = 1;
 370                 return 1;       /* let next XACTION START clean it up */
 371         }
 372         for (i = 1; i <= bt->read_count; i++)
 373                 bt->read_data[i] = BMC2HOST;
 374         bt->read_count++;       /* Account internally for length byte */
 375
 376         if (bt_debug & BT_DEBUG_MSG) {
 377                 int max = bt->read_count;
 378
 379                 printk(KERN_WARNING "BT: got %d bytes seq=0x%02X",
 380                         max, bt->read_data[2]);
 381                 if (max > 16)
 382                         max = 16;
 383                 for (i = 0; i < max; i++)
 384                         printk(KERN_CONT " %02x", bt->read_data[i]);
 385                 printk(KERN_CONT "%s\n", bt->read_count == max ? "" : " ...");
 386         }
 387
 388         /* per the spec, the (NetFn[1], Seq[2], Cmd[3]) tuples must match */
 389         if ((bt->read_data[3] == bt->write_data[3]) &&
 390             (bt->read_data[2] == bt->write_data[2]) &&
 391             ((bt->read_data[1] & 0xF8) == (bt->write_data[1] & 0xF8)))
 392                         return 1;
 393
 394         if (bt_debug & BT_DEBUG_MSG)
 395                 printk(KERN_WARNING "IPMI BT: bad packet: "
 396                 "want 0x(%02X, %02X, %02X) got (%02X, %02X, %02X)\n",
 397                 bt->write_data[1] | 0x04, bt->write_data[2], bt->write_data[3],
 398                 bt->read_data[1],  bt->read_data[2],  bt->read_data[3]);
 399         return 0;
 400 }
 401
 402 /* Restart if retries are left, or return an error completion code */
 403
 404 static enum si_sm_result error_recovery(struct si_sm_data *bt,
 405                                         unsigned char status,
 406                                         unsigned char cCode)
 407 {
 408         char *reason;
 409
 410         bt->timeout = bt->BT_CAP_req2rsp;
 411
 412         switch (cCode) {
 413         case IPMI_TIMEOUT_ERR:
 414                 reason = "timeout";
 415                 break;
 416         default:
 417                 reason = "internal error";
 418                 break;
 419         }
 420
 421         printk(KERN_WARNING "IPMI BT: %s in %s %s ",    /* open-ended line */
 422                 reason, STATE2TXT, STATUS2TXT);
 423
 424         /*
 425          * Per the IPMI spec, retries are based on the sequence number
 426          * known only to this module, so manage a restart here.
 427          */
 428         (bt->error_retries)++;
 429         if (bt->error_retries < bt->BT_CAP_retries) {
 430                 printk("%d retries left\n",
 431                         bt->BT_CAP_retries - bt->error_retries);
 432                 bt->state = BT_STATE_RESTART;
 433                 return SI_SM_CALL_WITHOUT_DELAY;
 434         }
 435
 436         printk(KERN_WARNING "failed %d retries, sending error response\n",
 437                bt->BT_CAP_retries);
 438         if (!bt->nonzero_status)
 439                 printk(KERN_ERR "IPMI BT: stuck, try power cycle\n");
 440
 441         /* this is most likely during insmod */
 442         else if (bt->seq <= (unsigned char)(bt->BT_CAP_retries & 0xFF)) {
 443                 printk(KERN_WARNING "IPMI: BT reset (takes 5 secs)\n");
 444                 bt->state = BT_STATE_RESET1;
 445                 return SI_SM_CALL_WITHOUT_DELAY;
 446         }
 447
 448         /*
 449          * Concoct a useful error message, set up the next state, and
 450          * be done with this sequence.
 451          */
 452
 453         bt->state = BT_STATE_IDLE;
 454         switch (cCode) {
 455         case IPMI_TIMEOUT_ERR:
 456                 if (status & BT_B_BUSY) {
 457                         cCode = IPMI_NODE_BUSY_ERR;
 458                         bt->state = BT_STATE_LONG_BUSY;
 459                 }
 460                 break;
 461         default:
 462                 break;
 463         }
 464         force_result(bt, cCode);
 465         return SI_SM_TRANSACTION_COMPLETE;
 466 }
 467
 468 /* Check status and (usually) take action and change this state machine. */
 469
 470 static enum si_sm_result bt_event(struct si_sm_data *bt, long time)
 471 {
 472         unsigned char status, BT_CAP[8];
 473         static enum bt_states last_printed = BT_STATE_PRINTME;
 474         int i;
 475
 476         status = BT_STATUS;
 477         bt->nonzero_status |= status;
 478         if ((bt_debug & BT_DEBUG_STATES) && (bt->state != last_printed)) {
 479                 printk(KERN_WARNING "BT: %s %s TO=%ld - %ld \n",
 480                         STATE2TXT,
 481                         STATUS2TXT,
 482                         bt->timeout,
 483                         time);
 484                 last_printed = bt->state;
 485         }
 486
 487         /*
 488          * Commands that time out may still (eventually) provide a response.
 489          * This stale response will get in the way of a new response so remove
 490          * it if possible (hopefully during IDLE).  Even if it comes up later
 491          * it will be rejected by its (now-forgotten) seq number.
 492          */
 493
 494         if ((bt->state < BT_STATE_WRITE_BYTES) && (status & BT_B2H_ATN)) {
 495                 drain_BMC2HOST(bt);
 496                 BT_SI_SM_RETURN(SI_SM_CALL_WITH_DELAY);
 497         }
 498
 499         if ((bt->state != BT_STATE_IDLE) &&
 500             (bt->state <  BT_STATE_PRINTME)) {
 501                 /* check timeout */
 502                 bt->timeout -= time;
 503                 if ((bt->timeout < 0) && (bt->state < BT_STATE_RESET1))
 504                         return error_recovery(bt,
 505                                               status,
 506                                               IPMI_TIMEOUT_ERR);
 507         }
 508
 509         switch (bt->state) {
 510
 511         /*
 512          * Idle state first checks for asynchronous messages from another
 513          * channel, then does some opportunistic housekeeping.
 514          */
 515
 516         case BT_STATE_IDLE:
 517                 if (status & BT_SMS_ATN) {
 518                         BT_CONTROL(BT_SMS_ATN); /* clear it */
 519                         return SI_SM_ATTN;
 520                 }
 521
 522                 if (status & BT_H_BUSY)         /* clear a leftover H_BUSY */
 523                         BT_CONTROL(BT_H_BUSY);
 524
 525                 /* Read BT capabilities if it hasn't been done yet */
 526                 if (!bt->BT_CAP_outreqs)
 527                         BT_STATE_CHANGE(BT_STATE_CAPABILITIES_BEGIN,
 528                                         SI_SM_CALL_WITHOUT_DELAY);
 529                 bt->timeout = bt->BT_CAP_req2rsp;
 530                 BT_SI_SM_RETURN(SI_SM_IDLE);
 531
 532         case BT_STATE_XACTION_START:
 533                 if (status & (BT_B_BUSY | BT_H2B_ATN))
 534                         BT_SI_SM_RETURN(SI_SM_CALL_WITH_DELAY);
 535                 if (BT_STATUS & BT_H_BUSY)
 536                         BT_CONTROL(BT_H_BUSY);  /* force clear */
 537                 BT_STATE_CHANGE(BT_STATE_WRITE_BYTES,
 538                                 SI_SM_CALL_WITHOUT_DELAY);
 539
 540         case BT_STATE_WRITE_BYTES:
 541                 if (status & BT_H_BUSY)
 542                         BT_CONTROL(BT_H_BUSY);  /* clear */
 543                 BT_CONTROL(BT_CLR_WR_PTR);
 544                 write_all_bytes(bt);
 545                 BT_CONTROL(BT_H2B_ATN); /* can clear too fast to catch */
 546                 BT_STATE_CHANGE(BT_STATE_WRITE_CONSUME,
 547                                 SI_SM_CALL_WITHOUT_DELAY);
 548
 549         case BT_STATE_WRITE_CONSUME:
 550                 if (status & (BT_B_BUSY | BT_H2B_ATN))
 551                         BT_SI_SM_RETURN(SI_SM_CALL_WITH_DELAY);
 552                 BT_STATE_CHANGE(BT_STATE_READ_WAIT,
 553                                 SI_SM_CALL_WITHOUT_DELAY);
 554
 555         /* Spinning hard can suppress B2H_ATN and force a timeout */
 556
 557         case BT_STATE_READ_WAIT:
 558                 if (!(status & BT_B2H_ATN))
 559                         BT_SI_SM_RETURN(SI_SM_CALL_WITH_DELAY);
 560                 BT_CONTROL(BT_H_BUSY);          /* set */
 561
 562                 /*
 563                  * Uncached, ordered writes should just proceed serially but
 564                  * some BMCs don't clear B2H_ATN with one hit.  Fast-path a
 565                  * workaround without too much penalty to the general case.
 566                  */
 567
 568                 BT_CONTROL(BT_B2H_ATN);         /* clear it to ACK the BMC */
 569                 BT_STATE_CHANGE(BT_STATE_CLEAR_B2H,
 570                                 SI_SM_CALL_WITHOUT_DELAY);
 571
 572         case BT_STATE_CLEAR_B2H:
 573                 if (status & BT_B2H_ATN) {
 574                         /* keep hitting it */
 575                         BT_CONTROL(BT_B2H_ATN);
 576                         BT_SI_SM_RETURN(SI_SM_CALL_WITH_DELAY);
 577                 }
 578                 BT_STATE_CHANGE(BT_STATE_READ_BYTES,
 579                                 SI_SM_CALL_WITHOUT_DELAY);
 580
 581         case BT_STATE_READ_BYTES:
 582                 if (!(status & BT_H_BUSY))
 583                         /* check in case of retry */
 584                         BT_CONTROL(BT_H_BUSY);
 585                 BT_CONTROL(BT_CLR_RD_PTR);      /* start of BMC2HOST buffer */
 586                 i = read_all_bytes(bt);         /* true == packet seq match */
 587                 BT_CONTROL(BT_H_BUSY);          /* NOW clear */
 588                 if (!i)                         /* Not my message */
 589                         BT_STATE_CHANGE(BT_STATE_READ_WAIT,
 590                                         SI_SM_CALL_WITHOUT_DELAY);
 591                 bt->state = bt->complete;
 592                 return bt->state == BT_STATE_IDLE ?     /* where to next? */
 593                         SI_SM_TRANSACTION_COMPLETE :    /* normal */
 594                         SI_SM_CALL_WITHOUT_DELAY;       /* Startup magic */
 595
 596         case BT_STATE_LONG_BUSY:        /* For example: after FW update */
 597                 if (!(status & BT_B_BUSY)) {
 598                         reset_flags(bt);        /* next state is now IDLE */
 599                         bt_init_data(bt, bt->io);
 600                 }
 601                 return SI_SM_CALL_WITH_DELAY;   /* No repeat printing */
 602
 603         case BT_STATE_RESET1:
 604                 reset_flags(bt);
 605                 drain_BMC2HOST(bt);
 606                 BT_STATE_CHANGE(BT_STATE_RESET2,
 607                                 SI_SM_CALL_WITH_DELAY);
 608
 609         case BT_STATE_RESET2:           /* Send a soft reset */
 610                 BT_CONTROL(BT_CLR_WR_PTR);
 611                 HOST2BMC(3);            /* number of bytes following */
 612                 HOST2BMC(0x18);         /* NetFn/LUN == Application, LUN 0 */
 613                 HOST2BMC(42);           /* Sequence number */
 614                 HOST2BMC(3);            /* Cmd == Soft reset */
 615                 BT_CONTROL(BT_H2B_ATN);
 616                 bt->timeout = BT_RESET_DELAY * USEC_PER_SEC;
 617                 BT_STATE_CHANGE(BT_STATE_RESET3,
 618                                 SI_SM_CALL_WITH_DELAY);
 619
 620         case BT_STATE_RESET3:           /* Hold off everything for a bit */
 621                 if (bt->timeout > 0)
 622                         return SI_SM_CALL_WITH_DELAY;
 623                 drain_BMC2HOST(bt);
 624                 BT_STATE_CHANGE(BT_STATE_RESTART,
 625                                 SI_SM_CALL_WITH_DELAY);
 626
 627         case BT_STATE_RESTART:          /* don't reset retries or seq! */
 628                 bt->read_count = 0;
 629                 bt->nonzero_status = 0;
 630                 bt->timeout = bt->BT_CAP_req2rsp;
 631                 BT_STATE_CHANGE(BT_STATE_XACTION_START,
 632                                 SI_SM_CALL_WITH_DELAY);
 633
 634         /*
 635          * Get BT Capabilities, using timing of upper level state machine.
 636          * Set outreqs to prevent infinite loop on timeout.
 637          */
 638         case BT_STATE_CAPABILITIES_BEGIN:
 639                 bt->BT_CAP_outreqs = 1;
 640                 {
 641                         unsigned char GetBT_CAP[] = { 0x18, 0x36 };
 642                         bt->state = BT_STATE_IDLE;
 643                         bt_start_transaction(bt, GetBT_CAP, sizeof(GetBT_CAP));
 644                 }
 645                 bt->complete = BT_STATE_CAPABILITIES_END;
 646                 BT_STATE_CHANGE(BT_STATE_XACTION_START,
 647                                 SI_SM_CALL_WITH_DELAY);
 648
 649         case BT_STATE_CAPABILITIES_END:
 650                 i = bt_get_result(bt, BT_CAP, sizeof(BT_CAP));
 651                 bt_init_data(bt, bt->io);
 652                 if ((i == 8) && !BT_CAP[2]) {
 653                         bt->BT_CAP_outreqs = BT_CAP[3];
 654                         bt->BT_CAP_req2rsp = BT_CAP[6] * USEC_PER_SEC;
 655                         bt->BT_CAP_retries = BT_CAP[7];
 656                 } else
 657                         printk(KERN_WARNING "IPMI BT: using default values\n");
 658                 if (!bt->BT_CAP_outreqs)
 659                         bt->BT_CAP_outreqs = 1;
 660                 printk(KERN_WARNING "IPMI BT: req2rsp=%ld secs retries=%d\n",
 661                         bt->BT_CAP_req2rsp / USEC_PER_SEC, bt->BT_CAP_retries);
 662                 bt->timeout = bt->BT_CAP_req2rsp;
 663                 return SI_SM_CALL_WITHOUT_DELAY;
 664
 665         default:        /* should never occur */
 666                 return error_recovery(bt,
 667                                       status,
 668                                       IPMI_ERR_UNSPECIFIED);
 669         }
 670         return SI_SM_CALL_WITH_DELAY;
 671 }
 672
 673 static int bt_detect(struct si_sm_data *bt)
 674 {
 675         /*
 676          * It's impossible for the BT status and interrupt registers to be
 677          * all 1's, (assuming a properly functioning, self-initialized BMC)
 678          * but that's what you get from reading a bogus address, so we
 679          * test that first.  The calling routine uses negative logic.
 680          */
 681
 682         if ((BT_STATUS == 0xFF) && (BT_INTMASK_R == 0xFF))
 683                 return 1;
 684         reset_flags(bt);
 685         return 0;
 686 }
 687
 688 static void bt_cleanup(struct si_sm_data *bt)
 689 {
 690 }
 691
 692 static int bt_size(void)
 693 {
 694         return sizeof(struct si_sm_data);
 695 }
 696
 697 struct si_sm_handlers bt_smi_handlers = {
 698         .init_data              = bt_init_data,
 699         .start_transaction      = bt_start_transaction,
 700         .get_result             = bt_get_result,
 701         .event                  = bt_event,
 702         .detect                 = bt_detect,
 703         .cleanup                = bt_cleanup,
 704         .size                   = bt_size,
 705 };