summaryrefslogtreecommitdiffstats
path: root/drivers/char/ipmi/ipmi_bt_sm.c
blob: 0030cd8e2e956cb436ae781c854ba41df23058a9 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
/*
 *  ipmi_bt_sm.c
 *
 *  The state machine for an Open IPMI BT sub-driver under ipmi_si.c, part
 *  of the driver architecture at http://sourceforge.net/project/openipmi
 *
 *  Author:	Rocky Craig <first.last@hp.com>
 *
 *  This program is free software; you can redistribute it and/or modify it
 *  under the terms of the GNU General Public License as published by the
 *  Free Software Foundation; either version 2 of the License, or (at your
 *  option) any later version.
 *
 *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
 *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 *  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 *  BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 *  OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 *  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
 *  TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
 *  USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  675 Mass Ave, Cambridge, MA 02139, USA.  */

#include <linux/kernel.h> /* For printk. */
#include <linux/string.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/ipmi_msgdefs.h>		/* for completion codes */
#include "ipmi_si_sm.h"

static int bt_debug = 0x00;	/* Production value 0, see following flags */

#define	BT_DEBUG_ENABLE	1
#define BT_DEBUG_MSG	2
#define BT_DEBUG_STATES	4
module_param(bt_debug, int, 0644);
MODULE_PARM_DESC(bt_debug, "debug bitmask, 1=enable, 2=messages, 4=states");

/* Typical "Get BT Capabilities" values are 2-3 retries, 5-10 seconds,
   and 64 byte buffers.  However, one HP implementation wants 255 bytes of
   buffer (with a documented message of 160 bytes) so go for the max.
   Since the Open IPMI architecture is single-message oriented at this
   stage, the queue depth of BT is of no concern. */

#define BT_NORMAL_TIMEOUT	5000000	/* seconds in microseconds */
#define BT_RETRY_LIMIT		2
#define BT_RESET_DELAY		6000000	/* 6 seconds after warm reset */

enum bt_states {
	BT_STATE_IDLE,
	BT_STATE_XACTION_START,
	BT_STATE_WRITE_BYTES,
	BT_STATE_WRITE_END,
	BT_STATE_WRITE_CONSUME,
	BT_STATE_B2H_WAIT,
	BT_STATE_READ_END,
	BT_STATE_RESET1,		/* These must come last */
	BT_STATE_RESET2,
	BT_STATE_RESET3,
	BT_STATE_RESTART,
	BT_STATE_HOSED
};

struct si_sm_data {
	enum bt_states	state;
	enum bt_states	last_state;	/* assist printing and resets */
	unsigned char	seq;		/* BT sequence number */
	struct si_sm_io	*io;
        unsigned char	write_data[IPMI_MAX_MSG_LENGTH];
        int		write_count;
        unsigned char	read_data[IPMI_MAX_MSG_LENGTH];
        int		read_count;
        int		truncated;
        long		timeout;
        unsigned int	error_retries;	/* end of "common" fields */
	int		nonzero_status;	/* hung BMCs stay all 0 */
};

#define BT_CLR_WR_PTR	0x01	/* See IPMI 1.5 table 11.6.4 */
#define BT_CLR_RD_PTR	0x02
#define BT_H2B_ATN	0x04
#define BT_B2H_ATN	0x08
#define BT_SMS_ATN	0x10
#define BT_OEM0		0x20
#define BT_H_BUSY	0x40
#define BT_B_BUSY	0x80

/* Some bits are toggled on each write: write once to set it, once
   more to clear it; writing a zero does nothing.  To absolutely
   clear it, check its state and write if set.  This avoids the "get
   current then use as mask" scheme to modify one bit.  Note that the
   variable "bt" is hardcoded into these macros. */

#define BT_STATUS	bt->io->inputb(bt->io, 0)
#define BT_CONTROL(x)	bt->io->outputb(bt->io, 0, x)

#define BMC2HOST	bt->io->inputb(bt->io, 1)
#define HOST2BMC(x)	bt->io->outputb(bt->io, 1, x)

#define BT_INTMASK_R	bt->io->inputb(bt->io, 2)
#define BT_INTMASK_W(x)	bt->io->outputb(bt->io, 2, x)

/* Convenience routines for debugging.  These are not multi-open safe!
   Note the macros have hardcoded variables in them. */

static char *state2txt(unsigned char state)
{
	switch (state) {
		case BT_STATE_IDLE:		return("IDLE");
		case BT_STATE_XACTION_START:	return("XACTION");
		case BT_STATE_WRITE_BYTES:	return("WR_BYTES");
		case BT_STATE_WRITE_END:	return("WR_END");
		case BT_STATE_WRITE_CONSUME:	return("WR_CONSUME");
		case BT_STATE_B2H_WAIT:		return("B2H_WAIT");
		case BT_STATE_READ_END:		return("RD_END");
		case BT_STATE_RESET1:		return("RESET1");
		case BT_STATE_RESET2:		return("RESET2");
		case BT_STATE_RESET3:		return("RESET3");
		case BT_STATE_RESTART:		return("RESTART");
		case BT_STATE_HOSED:		return("HOSED");
	}
	return("BAD STATE");
}
#define STATE2TXT state2txt(bt->state)

static char *status2txt(unsigned char status, char *buf)
{
	strcpy(buf, "[ ");
	if (status & BT_B_BUSY) strcat(buf, "B_BUSY ");
	if (status & BT_H_BUSY) strcat(buf, "H_BUSY ");
	if (status & BT_OEM0) strcat(buf, "OEM0 ");
	if (status & BT_SMS_ATN) strcat(buf, "SMS ");
	if (status & BT_B2H_ATN) strcat(buf, "B2H ");
	if (status & BT_H2B_ATN) strcat(buf, "H2B ");
	strcat(buf, "]");
	return buf;
}
#define STATUS2TXT(buf) status2txt(status, buf)

/* This will be called from within this module on a hosed condition */
#define FIRST_SEQ	0
static unsigned int bt_init_data(struct si_sm_data *bt, struct si_sm_io *io)
{
	bt->state = BT_STATE_IDLE;
	bt->last_state = BT_STATE_IDLE;
	bt->seq = FIRST_SEQ;
	bt->io = io;
	bt->write_count = 0;
	bt->read_count = 0;
	bt->error_retries = 0;
	bt->nonzero_status = 0;
	bt->truncated = 0;
	bt->timeout = BT_NORMAL_TIMEOUT;
	return 3; /* We claim 3 bytes of space; ought to check SPMI table */
}

static int bt_start_transaction(struct si_sm_data *bt,
				unsigned char *data,
				unsigned int size)
{
	unsigned int i;

	if ((size < 2) || (size > (IPMI_MAX_MSG_LENGTH - 2)))
	       return -1;

	if ((bt->state != BT_STATE_IDLE) && (bt->state != BT_STATE_HOSED))
		return -2;

	if (bt_debug & BT_DEBUG_MSG) {
    		printk(KERN_WARNING "+++++++++++++++++++++++++++++++++++++\n");
		printk(KERN_WARNING "BT: write seq=0x%02X:", bt->seq);
		for (i = 0; i < size; i ++)
		       printk (" %02x", data[i]);
		printk("\n");
	}
	bt->write_data[0] = size + 1;	/* all data plus seq byte */
	bt->write_data[1] = *data;	/* NetFn/LUN */
	bt->write_data[2] = bt->seq;
	memcpy(bt->write_data + 3, data + 1, size - 1);
	bt->write_count = size + 2;

	bt->error_retries = 0;
	bt->nonzero_status = 0;
	bt->read_count = 0;
	bt->truncated = 0;
	bt->state = BT_STATE_XACTION_START;
	bt->last_state = BT_STATE_IDLE;
	bt->timeout = BT_NORMAL_TIMEOUT;
	return 0;
}

/* After the upper state machine has been told SI_SM_TRANSACTION_COMPLETE
   it calls this.  Strip out the length and seq bytes. */

static int bt_get_result(struct si_sm_data *bt,
			   unsigned char *data,
			   unsigned int length)
{
	int i, msg_len;

	msg_len = bt->read_count - 2;		/* account for length & seq */
	/* Always NetFn, Cmd, cCode */
	if (msg_len < 3 || msg_len > IPMI_MAX_MSG_LENGTH) {
		printk(KERN_DEBUG "BT results: bad msg_len = %d\n", msg_len);
		data[0] = bt->write_data[1] | 0x4;	/* Kludge a response */
		data[1] = bt->write_data[3];
		data[2] = IPMI_ERR_UNSPECIFIED;
		msg_len = 3;
	} else {
		data[0] = bt->read_data[1];
		data[1] = bt->read_data[3];
		if (length < msg_len)
		       bt->truncated = 1;
		if (bt->truncated) {	/* can be set in read_all_bytes() */
			data[2] = IPMI_ERR_MSG_TRUNCATED;
			msg_len = 3;
		} else
		       memcpy(data + 2, bt->read_data + 4, msg_len - 2);

		if (bt_debug & BT_DEBUG_MSG) {
			printk (KERN_WARNING "BT: res (raw)");
			for (i = 0; i < msg_len; i++)
			       printk(" %02x", data[i]);
			printk ("\n");
		}
	}
	bt->read_count = 0;	/* paranoia */
	return msg_len;
}

/* This bit's functionality is optional */
#define BT_BMC_HWRST	0x80

static void reset_flags(struct si_sm_data *bt)
{
	if (BT_STATUS & BT_H_BUSY)
	       BT_CONTROL(BT_H_BUSY);
	if (BT_STATUS & BT_B_BUSY)
	       BT_CONTROL(BT_B_BUSY);
	BT_CONTROL(BT_CLR_WR_PTR);
	BT_CONTROL(BT_SMS_ATN);

	if (BT_STATUS & BT_B2H_ATN) {
		int i;
		BT_CONTROL(BT_H_BUSY);
		BT_CONTROL(BT_B2H_ATN);
		BT_CONTROL(BT_CLR_RD_PTR);
		for (i = 0; i < IPMI_MAX_MSG_LENGTH + 2; i++)
		       BMC2HOST;
		BT_CONTROL(BT_H_BUSY);
	}
}

static inline void write_all_bytes(struct si_sm_data *bt)
{
	int i;

	if (bt_debug & BT_DEBUG_MSG) {
    		printk(KERN_WARNING "BT: write %d bytes seq=0x%02X",
			bt->write_count, bt->seq);
		for (i = 0; i < bt->write_count; i++)
			printk (" %02x", bt->write_data[i]);
		printk ("\n");
	}
	for (i = 0; i < bt->write_count; i++)
	       HOST2BMC(bt->write_data[i]);
}

static inline int read_all_bytes(struct si_sm_data *bt)
{
	unsigned char i;

	bt->read_data[0] = BMC2HOST;
	bt->read_count = bt->read_data[0];
	if (bt_debug & BT_DEBUG_MSG)
    		printk(KERN_WARNING "BT: read %d bytes:", bt->read_count);

	/* minimum: length, NetFn, Seq, Cmd, cCode == 5 total, or 4 more
	   following the length byte. */
	if (bt->read_count < 4 || bt->read_count >= IPMI_MAX_MSG_LENGTH) {
		if (bt_debug & BT_DEBUG_MSG)
			printk("bad length %d\n", bt->read_count);
		bt->truncated = 1;
		return 1;	/* let next XACTION START clean it up */
	}
	for (i = 1; i <= bt->read_count; i++)
	       bt->read_data[i] = BMC2HOST;
	bt->read_count++;	/* account for the length byte */

	if (bt_debug & BT_DEBUG_MSG) {
	    	for (i = 0; i < bt->read_count; i++)
			printk (" %02x", bt->read_data[i]);
	    	printk ("\n");
	}
	if (bt->seq != bt->write_data[2])	/* idiot check */
		printk(KERN_DEBUG "BT: internal error: sequence mismatch\n");

	/* per the spec, the (NetFn, Seq, Cmd) tuples should match */
	if ((bt->read_data[3] == bt->write_data[3]) &&		/* Cmd */
        	(bt->read_data[2] == bt->write_data[2]) &&	/* Sequence */
        	((bt->read_data[1] & 0xF8) == (bt->write_data[1] & 0xF8)))
			return 1;

	if (bt_debug & BT_DEBUG_MSG)
	       printk(KERN_WARNING "BT: bad packet: "
		"want 0x(%02X, %02X, %02X) got (%02X, %02X, %02X)\n",
		bt->write_data[1], bt->write_data[2], bt->write_data[3],
		bt->read_data[1],  bt->read_data[2],  bt->read_data[3]);
	return 0;
}

/* Modifies bt->state appropriately, need to get into the bt_event() switch */

static void error_recovery(struct si_sm_data *bt, char *reason)
{
	unsigned char status;
	char buf[40]; /* For getting status */

	bt->timeout = BT_NORMAL_TIMEOUT; /* various places want to retry */

	status = BT_STATUS;
	printk(KERN_DEBUG "BT: %s in %s %s\n", reason, STATE2TXT,
	       STATUS2TXT(buf));

	(bt->error_retries)++;
	if (bt->error_retries > BT_RETRY_LIMIT) {
		printk(KERN_DEBUG "retry limit (%d) exceeded\n", BT_RETRY_LIMIT);
		bt->state = BT_STATE_HOSED;
		if (!bt->nonzero_status)
			printk(KERN_ERR "IPMI: BT stuck, try power cycle\n");
		else if (bt->error_retries <= BT_RETRY_LIMIT + 1) {
			printk(KERN_DEBUG "IPMI: BT reset (takes 5 secs)\n");
        		bt->state = BT_STATE_RESET1;
		}
	return;
	}

	/* Sometimes the BMC queues get in an "off-by-one" state...*/
	if ((bt->state == BT_STATE_B2H_WAIT) && (status & BT_B2H_ATN)) {
    		printk(KERN_DEBUG "retry B2H_WAIT\n");
		return;
	}

	printk(KERN_DEBUG "restart command\n");
	bt->state = BT_STATE_RESTART;
}

/* Check the status and (possibly) advance the BT state machine.  The
   default return is SI_SM_CALL_WITH_DELAY. */

static enum si_sm_result bt_event(struct si_sm_data *bt, long time)
{
	unsigned char status;
	char buf[40]; /* For getting status */
	int i;

	status = BT_STATUS;
	bt->nonzero_status |= status;

	if ((bt_debug & BT_DEBUG_STATES) && (bt->state != bt->last_state))
		printk(KERN_WARNING "BT: %s %s TO=%ld - %ld \n",
			STATE2TXT,
			STATUS2TXT(buf),
			bt->timeout,
			time);
	bt->last_state = bt->state;

	if (bt->state == BT_STATE_HOSED)
	       return SI_SM_HOSED;

	if (bt->state != BT_STATE_IDLE) {	/* do timeout test */
		bt->timeout -= time;
		if ((bt->timeout < 0) && (bt->state < BT_STATE_RESET1)) {
			error_recovery(bt, "timed out");
			return SI_SM_CALL_WITHOUT_DELAY;
		}
	}

	switch (bt->state) {

    	case BT_STATE_IDLE:	/* check for asynchronous messages */
		if (status & BT_SMS_ATN) {
			BT_CONTROL(BT_SMS_ATN);	/* clear it */
			return SI_SM_ATTN;
		}
		return SI_SM_IDLE;

	case BT_STATE_XACTION_START:
		if (status & BT_H_BUSY) {
			BT_CONTROL(BT_H_BUSY);
			break;
		}
    		if (status & BT_B2H_ATN)
		       break;
		bt->state = BT_STATE_WRITE_BYTES;
		return SI_SM_CALL_WITHOUT_DELAY;	/* for logging */

	case BT_STATE_WRITE_BYTES:
		if (status & (BT_B_BUSY | BT_H2B_ATN))
		       break;
		BT_CONTROL(BT_CLR_WR_PTR);
		write_all_bytes(bt);
		BT_CONTROL(BT_H2B_ATN);	/* clears too fast to catch? */
		bt->state = BT_STATE_WRITE_CONSUME;
		return SI_SM_CALL_WITHOUT_DELAY; /* it MIGHT sail through */

	case BT_STATE_WRITE_CONSUME: /* BMCs usually blow right thru here */
        	if (status & (BT_H2B_ATN | BT_B_BUSY))
		       break;
		bt->state = BT_STATE_B2H_WAIT;
		/* fall through with status */

	/* Stay in BT_STATE_B2H_WAIT until a packet matches.  However, spinning
	   hard here, constantly reading status, seems to hold off the
	   generation of B2H_ATN so ALWAYS return CALL_WITH_DELAY. */

	case BT_STATE_B2H_WAIT:
    		if (!(status & BT_B2H_ATN))
		       break;

		/* Assume ordered, uncached writes: no need to wait */
		if (!(status & BT_H_BUSY))
		       BT_CONTROL(BT_H_BUSY); /* set */
		BT_CONTROL(BT_B2H_ATN);		/* clear it, ACK to the BMC */
		BT_CONTROL(BT_CLR_RD_PTR);	/* reset the queue */
		i = read_all_bytes(bt);
		BT_CONTROL(BT_H_BUSY);		/* clear */
		if (!i)				/* Try this state again */
		       break;
		bt->state = BT_STATE_READ_END;
		return SI_SM_CALL_WITHOUT_DELAY;	/* for logging */

    	case BT_STATE_READ_END:

		/* I could wait on BT_H_BUSY to go clear for a truly clean
		   exit.  However, this is already done in XACTION_START
		   and the (possible) extra loop/status/possible wait affects
		   performance.  So, as long as it works, just ignore H_BUSY */

#ifdef MAKE_THIS_TRUE_IF_NECESSARY

		if (status & BT_H_BUSY)
		       break;
#endif
		bt->seq++;
		bt->state = BT_STATE_IDLE;
		return SI_SM_TRANSACTION_COMPLETE;

	case BT_STATE_RESET1:
    		reset_flags(bt);
    		bt->timeout = BT_RESET_DELAY;
		bt->state = BT_STATE_RESET2;
		break;

	case BT_STATE_RESET2:		/* Send a soft reset */
		BT_CONTROL(BT_CLR_WR_PTR);
		HOST2BMC(3);		/* number of bytes following */
		HOST2BMC(0x18);		/* NetFn/LUN == Application, LUN 0 */
		HOST2BMC(42);		/* Sequence number */
		HOST2BMC(3);		/* Cmd == Soft reset */
		BT_CONTROL(BT_H2B_ATN);
		bt->state = BT_STATE_RESET3;
		break;

	case BT_STATE_RESET3:
		if (bt->timeout > 0)
		       return SI_SM_CALL_WITH_DELAY;
		bt->state = BT_STATE_RESTART;	/* printk in debug modes */
		break;

	case BT_STATE_RESTART:		/* don't reset retries! */
		reset_flags(bt);
		bt->write_data[2] = ++bt->seq;
		bt->read_count = 0;
		bt->nonzero_status = 0;
		bt->timeout = BT_NORMAL_TIMEOUT;
		bt->state = BT_STATE_XACTION_START;
		break;

	default:	/* HOSED is supposed to be caught much earlier */
		error_recovery(bt, "internal logic error");
		break;
  	}
  	return SI_SM_CALL_WITH_DELAY;
}

static int bt_detect(struct si_sm_data *bt)
{
	/* It's impossible for the BT status and interrupt registers to be
	   all 1's, (assuming a properly functioning, self-initialized BMC)
	   but that's what you get from reading a bogus address, so we
	   test that first.  The calling routine uses negative logic. */

	if ((BT_STATUS == 0xFF) && (BT_INTMASK_R == 0xFF))
	       return 1;
	reset_flags(bt);
	return 0;
}

static void bt_cleanup(struct si_sm_data *bt)
{
}

static int bt_size(void)
{
	return sizeof(struct si_sm_data);
}

struct si_sm_handlers bt_smi_handlers =
{
	.init_data         = bt_init_data,
	.start_transaction = bt_start_transaction,
	.get_result        = bt_get_result,
	.event             = bt_event,
	.detect            = bt_detect,
	.cleanup           = bt_cleanup,
	.size              = bt_size,
};