xref: /linux/drivers/char/ipmi/ipmi_ssif.c (revision 69bfec7548f4c1595bac0e3ddfc0458a5af31f4c)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * ipmi_ssif.c
4  *
5  * The interface to the IPMI driver for SMBus access to a SMBus
6  * compliant device.  Called SSIF by the IPMI spec.
7  *
8  * Author: Intel Corporation
9  *         Todd Davis <todd.c.davis@intel.com>
10  *
11  * Rewritten by Corey Minyard <minyard@acm.org> to support the
12  * non-blocking I2C interface, add support for multi-part
13  * transactions, add PEC support, and general clenaup.
14  *
15  * Copyright 2003 Intel Corporation
16  * Copyright 2005 MontaVista Software
17  */
18 
19 /*
20  * This file holds the "policy" for the interface to the SSIF state
21  * machine.  It does the configuration, handles timers and interrupts,
22  * and drives the real SSIF state machine.
23  */
24 
25 #define pr_fmt(fmt) "ipmi_ssif: " fmt
26 #define dev_fmt(fmt) "ipmi_ssif: " fmt
27 
28 #if defined(MODVERSIONS)
29 #include <linux/modversions.h>
30 #endif
31 
32 #include <linux/module.h>
33 #include <linux/moduleparam.h>
34 #include <linux/sched.h>
35 #include <linux/seq_file.h>
36 #include <linux/timer.h>
37 #include <linux/delay.h>
38 #include <linux/errno.h>
39 #include <linux/spinlock.h>
40 #include <linux/slab.h>
41 #include <linux/list.h>
42 #include <linux/i2c.h>
43 #include <linux/ipmi_smi.h>
44 #include <linux/init.h>
45 #include <linux/dmi.h>
46 #include <linux/kthread.h>
47 #include <linux/acpi.h>
48 #include <linux/ctype.h>
49 #include <linux/time64.h>
50 #include "ipmi_dmi.h"
51 
52 #define DEVICE_NAME "ipmi_ssif"
53 
54 #define IPMI_GET_SYSTEM_INTERFACE_CAPABILITIES_CMD	0x57
55 
56 #define	SSIF_IPMI_REQUEST			2
57 #define	SSIF_IPMI_MULTI_PART_REQUEST_START	6
58 #define	SSIF_IPMI_MULTI_PART_REQUEST_MIDDLE	7
59 #define	SSIF_IPMI_MULTI_PART_REQUEST_END	8
60 #define	SSIF_IPMI_RESPONSE			3
61 #define	SSIF_IPMI_MULTI_PART_RESPONSE_MIDDLE	9
62 
63 /* ssif_debug is a bit-field
64  *	SSIF_DEBUG_MSG -	commands and their responses
65  *	SSIF_DEBUG_STATES -	message states
66  *	SSIF_DEBUG_TIMING -	 Measure times between events in the driver
67  */
68 #define SSIF_DEBUG_TIMING	4
69 #define SSIF_DEBUG_STATE	2
70 #define SSIF_DEBUG_MSG		1
71 #define SSIF_NODEBUG		0
72 #define SSIF_DEFAULT_DEBUG	(SSIF_NODEBUG)
73 
74 /*
75  * Timer values
76  */
77 #define SSIF_MSG_USEC		60000	/* 60ms between message tries (T3). */
78 #define SSIF_REQ_RETRY_USEC	60000	/* 60ms between send retries (T6). */
79 #define SSIF_MSG_PART_USEC	5000	/* 5ms for a message part */
80 
81 /* How many times to we retry sending/receiving the message. */
82 #define	SSIF_SEND_RETRIES	5
83 #define	SSIF_RECV_RETRIES	250
84 
85 #define SSIF_MSG_MSEC		(SSIF_MSG_USEC / 1000)
86 #define SSIF_REQ_RETRY_MSEC	(SSIF_REQ_RETRY_USEC / 1000)
87 #define SSIF_MSG_JIFFIES	((SSIF_MSG_USEC * 1000) / TICK_NSEC)
88 #define SSIF_REQ_RETRY_JIFFIES	((SSIF_REQ_RETRY_USEC * 1000) / TICK_NSEC)
89 #define SSIF_MSG_PART_JIFFIES	((SSIF_MSG_PART_USEC * 1000) / TICK_NSEC)
90 
91 /*
92  * Timeout for the watch, only used for get flag timer.
93  */
94 #define SSIF_WATCH_MSG_TIMEOUT		msecs_to_jiffies(10)
95 #define SSIF_WATCH_WATCHDOG_TIMEOUT	msecs_to_jiffies(250)
96 
97 enum ssif_intf_state {
98 	SSIF_IDLE,
99 	SSIF_GETTING_FLAGS,
100 	SSIF_GETTING_EVENTS,
101 	SSIF_CLEARING_FLAGS,
102 	SSIF_GETTING_MESSAGES,
103 	/* FIXME - add watchdog stuff. */
104 };
105 
106 #define IS_SSIF_IDLE(ssif) ((ssif)->ssif_state == SSIF_IDLE \
107 			    && (ssif)->curr_msg == NULL)
108 
109 /*
110  * Indexes into stats[] in ssif_info below.
111  */
112 enum ssif_stat_indexes {
113 	/* Number of total messages sent. */
114 	SSIF_STAT_sent_messages = 0,
115 
116 	/*
117 	 * Number of message parts sent.  Messages may be broken into
118 	 * parts if they are long.
119 	 */
120 	SSIF_STAT_sent_messages_parts,
121 
122 	/*
123 	 * Number of time a message was retried.
124 	 */
125 	SSIF_STAT_send_retries,
126 
127 	/*
128 	 * Number of times the send of a message failed.
129 	 */
130 	SSIF_STAT_send_errors,
131 
132 	/*
133 	 * Number of message responses received.
134 	 */
135 	SSIF_STAT_received_messages,
136 
137 	/*
138 	 * Number of message fragments received.
139 	 */
140 	SSIF_STAT_received_message_parts,
141 
142 	/*
143 	 * Number of times the receive of a message was retried.
144 	 */
145 	SSIF_STAT_receive_retries,
146 
147 	/*
148 	 * Number of errors receiving messages.
149 	 */
150 	SSIF_STAT_receive_errors,
151 
152 	/*
153 	 * Number of times a flag fetch was requested.
154 	 */
155 	SSIF_STAT_flag_fetches,
156 
157 	/*
158 	 * Number of times the hardware didn't follow the state machine.
159 	 */
160 	SSIF_STAT_hosed,
161 
162 	/*
163 	 * Number of received events.
164 	 */
165 	SSIF_STAT_events,
166 
167 	/* Number of asyncronous messages received. */
168 	SSIF_STAT_incoming_messages,
169 
170 	/* Number of watchdog pretimeouts. */
171 	SSIF_STAT_watchdog_pretimeouts,
172 
173 	/* Number of alers received. */
174 	SSIF_STAT_alerts,
175 
176 	/* Always add statistics before this value, it must be last. */
177 	SSIF_NUM_STATS
178 };
179 
180 struct ssif_addr_info {
181 	struct i2c_board_info binfo;
182 	char *adapter_name;
183 	int debug;
184 	int slave_addr;
185 	enum ipmi_addr_src addr_src;
186 	union ipmi_smi_info_union addr_info;
187 	struct device *dev;
188 	struct i2c_client *client;
189 
190 	struct mutex clients_mutex;
191 	struct list_head clients;
192 
193 	struct list_head link;
194 };
195 
196 struct ssif_info;
197 
198 typedef void (*ssif_i2c_done)(struct ssif_info *ssif_info, int result,
199 			     unsigned char *data, unsigned int len);
200 
201 struct ssif_info {
202 	struct ipmi_smi     *intf;
203 	spinlock_t	    lock;
204 	struct ipmi_smi_msg *waiting_msg;
205 	struct ipmi_smi_msg *curr_msg;
206 	enum ssif_intf_state ssif_state;
207 	unsigned long       ssif_debug;
208 
209 	struct ipmi_smi_handlers handlers;
210 
211 	enum ipmi_addr_src addr_source; /* ACPI, PCI, SMBIOS, hardcode, etc. */
212 	union ipmi_smi_info_union addr_info;
213 
214 	/*
215 	 * Flags from the last GET_MSG_FLAGS command, used when an ATTN
216 	 * is set to hold the flags until we are done handling everything
217 	 * from the flags.
218 	 */
219 #define RECEIVE_MSG_AVAIL	0x01
220 #define EVENT_MSG_BUFFER_FULL	0x02
221 #define WDT_PRE_TIMEOUT_INT	0x08
222 	unsigned char       msg_flags;
223 
224 	u8		    global_enables;
225 	bool		    has_event_buffer;
226 	bool		    supports_alert;
227 
228 	/*
229 	 * Used to tell what we should do with alerts.  If we are
230 	 * waiting on a response, read the data immediately.
231 	 */
232 	bool		    got_alert;
233 	bool		    waiting_alert;
234 
235 	/* Used to inform the timeout that it should do a resend. */
236 	bool		    do_resend;
237 
238 	/*
239 	 * If set to true, this will request events the next time the
240 	 * state machine is idle.
241 	 */
242 	bool                req_events;
243 
244 	/*
245 	 * If set to true, this will request flags the next time the
246 	 * state machine is idle.
247 	 */
248 	bool                req_flags;
249 
250 	/* Used for sending/receiving data.  +1 for the length. */
251 	unsigned char data[IPMI_MAX_MSG_LENGTH + 1];
252 	unsigned int  data_len;
253 
254 	/* Temp receive buffer, gets copied into data. */
255 	unsigned char recv[I2C_SMBUS_BLOCK_MAX];
256 
257 	struct i2c_client *client;
258 	ssif_i2c_done done_handler;
259 
260 	/* Thread interface handling */
261 	struct task_struct *thread;
262 	struct completion wake_thread;
263 	bool stopping;
264 	int i2c_read_write;
265 	int i2c_command;
266 	unsigned char *i2c_data;
267 	unsigned int i2c_size;
268 
269 	struct timer_list retry_timer;
270 	int retries_left;
271 
272 	long watch_timeout;		/* Timeout for flags check, 0 if off. */
273 	struct timer_list watch_timer;	/* Flag fetch timer. */
274 
275 	/* Info from SSIF cmd */
276 	unsigned char max_xmit_msg_size;
277 	unsigned char max_recv_msg_size;
278 	bool cmd8_works; /* See test_multipart_messages() for details. */
279 	unsigned int  multi_support;
280 	int           supports_pec;
281 
282 #define SSIF_NO_MULTI		0
283 #define SSIF_MULTI_2_PART	1
284 #define SSIF_MULTI_n_PART	2
285 	unsigned char *multi_data;
286 	unsigned int  multi_len;
287 	unsigned int  multi_pos;
288 
289 	atomic_t stats[SSIF_NUM_STATS];
290 };
291 
292 #define ssif_inc_stat(ssif, stat) \
293 	atomic_inc(&(ssif)->stats[SSIF_STAT_ ## stat])
294 #define ssif_get_stat(ssif, stat) \
295 	((unsigned int) atomic_read(&(ssif)->stats[SSIF_STAT_ ## stat]))
296 
297 static bool initialized;
298 static bool platform_registered;
299 
300 static void return_hosed_msg(struct ssif_info *ssif_info,
301 			     struct ipmi_smi_msg *msg);
302 static void start_next_msg(struct ssif_info *ssif_info, unsigned long *flags);
303 static int start_send(struct ssif_info *ssif_info,
304 		      unsigned char   *data,
305 		      unsigned int    len);
306 
307 static unsigned long *ipmi_ssif_lock_cond(struct ssif_info *ssif_info,
308 					  unsigned long *flags)
309 	__acquires(&ssif_info->lock)
310 {
311 	spin_lock_irqsave(&ssif_info->lock, *flags);
312 	return flags;
313 }
314 
315 static void ipmi_ssif_unlock_cond(struct ssif_info *ssif_info,
316 				  unsigned long *flags)
317 	__releases(&ssif_info->lock)
318 {
319 	spin_unlock_irqrestore(&ssif_info->lock, *flags);
320 }
321 
322 static void deliver_recv_msg(struct ssif_info *ssif_info,
323 			     struct ipmi_smi_msg *msg)
324 {
325 	if (msg->rsp_size < 0) {
326 		return_hosed_msg(ssif_info, msg);
327 		dev_err(&ssif_info->client->dev,
328 			"%s: Malformed message: rsp_size = %d\n",
329 		       __func__, msg->rsp_size);
330 	} else {
331 		ipmi_smi_msg_received(ssif_info->intf, msg);
332 	}
333 }
334 
335 static void return_hosed_msg(struct ssif_info *ssif_info,
336 			     struct ipmi_smi_msg *msg)
337 {
338 	ssif_inc_stat(ssif_info, hosed);
339 
340 	/* Make it a response */
341 	msg->rsp[0] = msg->data[0] | 4;
342 	msg->rsp[1] = msg->data[1];
343 	msg->rsp[2] = 0xFF; /* Unknown error. */
344 	msg->rsp_size = 3;
345 
346 	deliver_recv_msg(ssif_info, msg);
347 }
348 
349 /*
350  * Must be called with the message lock held.  This will release the
351  * message lock.  Note that the caller will check IS_SSIF_IDLE and
352  * start a new operation, so there is no need to check for new
353  * messages to start in here.
354  */
355 static void start_clear_flags(struct ssif_info *ssif_info, unsigned long *flags)
356 {
357 	unsigned char msg[3];
358 
359 	ssif_info->msg_flags &= ~WDT_PRE_TIMEOUT_INT;
360 	ssif_info->ssif_state = SSIF_CLEARING_FLAGS;
361 	ipmi_ssif_unlock_cond(ssif_info, flags);
362 
363 	/* Make sure the watchdog pre-timeout flag is not set at startup. */
364 	msg[0] = (IPMI_NETFN_APP_REQUEST << 2);
365 	msg[1] = IPMI_CLEAR_MSG_FLAGS_CMD;
366 	msg[2] = WDT_PRE_TIMEOUT_INT;
367 
368 	if (start_send(ssif_info, msg, 3) != 0) {
369 		/* Error, just go to normal state. */
370 		ssif_info->ssif_state = SSIF_IDLE;
371 	}
372 }
373 
374 static void start_flag_fetch(struct ssif_info *ssif_info, unsigned long *flags)
375 {
376 	unsigned char mb[2];
377 
378 	ssif_info->req_flags = false;
379 	ssif_info->ssif_state = SSIF_GETTING_FLAGS;
380 	ipmi_ssif_unlock_cond(ssif_info, flags);
381 
382 	mb[0] = (IPMI_NETFN_APP_REQUEST << 2);
383 	mb[1] = IPMI_GET_MSG_FLAGS_CMD;
384 	if (start_send(ssif_info, mb, 2) != 0)
385 		ssif_info->ssif_state = SSIF_IDLE;
386 }
387 
388 static void check_start_send(struct ssif_info *ssif_info, unsigned long *flags,
389 			     struct ipmi_smi_msg *msg)
390 {
391 	if (start_send(ssif_info, msg->data, msg->data_size) != 0) {
392 		unsigned long oflags;
393 
394 		flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
395 		ssif_info->curr_msg = NULL;
396 		ssif_info->ssif_state = SSIF_IDLE;
397 		ipmi_ssif_unlock_cond(ssif_info, flags);
398 		ipmi_free_smi_msg(msg);
399 	}
400 }
401 
402 static void start_event_fetch(struct ssif_info *ssif_info, unsigned long *flags)
403 {
404 	struct ipmi_smi_msg *msg;
405 
406 	ssif_info->req_events = false;
407 
408 	msg = ipmi_alloc_smi_msg();
409 	if (!msg) {
410 		ssif_info->ssif_state = SSIF_IDLE;
411 		ipmi_ssif_unlock_cond(ssif_info, flags);
412 		return;
413 	}
414 
415 	ssif_info->curr_msg = msg;
416 	ssif_info->ssif_state = SSIF_GETTING_EVENTS;
417 	ipmi_ssif_unlock_cond(ssif_info, flags);
418 
419 	msg->data[0] = (IPMI_NETFN_APP_REQUEST << 2);
420 	msg->data[1] = IPMI_READ_EVENT_MSG_BUFFER_CMD;
421 	msg->data_size = 2;
422 
423 	check_start_send(ssif_info, flags, msg);
424 }
425 
426 static void start_recv_msg_fetch(struct ssif_info *ssif_info,
427 				 unsigned long *flags)
428 {
429 	struct ipmi_smi_msg *msg;
430 
431 	msg = ipmi_alloc_smi_msg();
432 	if (!msg) {
433 		ssif_info->ssif_state = SSIF_IDLE;
434 		ipmi_ssif_unlock_cond(ssif_info, flags);
435 		return;
436 	}
437 
438 	ssif_info->curr_msg = msg;
439 	ssif_info->ssif_state = SSIF_GETTING_MESSAGES;
440 	ipmi_ssif_unlock_cond(ssif_info, flags);
441 
442 	msg->data[0] = (IPMI_NETFN_APP_REQUEST << 2);
443 	msg->data[1] = IPMI_GET_MSG_CMD;
444 	msg->data_size = 2;
445 
446 	check_start_send(ssif_info, flags, msg);
447 }
448 
449 /*
450  * Must be called with the message lock held.  This will release the
451  * message lock.  Note that the caller will check IS_SSIF_IDLE and
452  * start a new operation, so there is no need to check for new
453  * messages to start in here.
454  */
455 static void handle_flags(struct ssif_info *ssif_info, unsigned long *flags)
456 {
457 	if (ssif_info->msg_flags & WDT_PRE_TIMEOUT_INT) {
458 		/* Watchdog pre-timeout */
459 		ssif_inc_stat(ssif_info, watchdog_pretimeouts);
460 		start_clear_flags(ssif_info, flags);
461 		ipmi_smi_watchdog_pretimeout(ssif_info->intf);
462 	} else if (ssif_info->msg_flags & RECEIVE_MSG_AVAIL)
463 		/* Messages available. */
464 		start_recv_msg_fetch(ssif_info, flags);
465 	else if (ssif_info->msg_flags & EVENT_MSG_BUFFER_FULL)
466 		/* Events available. */
467 		start_event_fetch(ssif_info, flags);
468 	else {
469 		ssif_info->ssif_state = SSIF_IDLE;
470 		ipmi_ssif_unlock_cond(ssif_info, flags);
471 	}
472 }
473 
474 static int ipmi_ssif_thread(void *data)
475 {
476 	struct ssif_info *ssif_info = data;
477 
478 	while (!kthread_should_stop()) {
479 		int result;
480 
481 		/* Wait for something to do */
482 		result = wait_for_completion_interruptible(
483 						&ssif_info->wake_thread);
484 		if (ssif_info->stopping)
485 			break;
486 		if (result == -ERESTARTSYS)
487 			continue;
488 		init_completion(&ssif_info->wake_thread);
489 
490 		if (ssif_info->i2c_read_write == I2C_SMBUS_WRITE) {
491 			result = i2c_smbus_write_block_data(
492 				ssif_info->client, ssif_info->i2c_command,
493 				ssif_info->i2c_data[0],
494 				ssif_info->i2c_data + 1);
495 			ssif_info->done_handler(ssif_info, result, NULL, 0);
496 		} else {
497 			result = i2c_smbus_read_block_data(
498 				ssif_info->client, ssif_info->i2c_command,
499 				ssif_info->i2c_data);
500 			if (result < 0)
501 				ssif_info->done_handler(ssif_info, result,
502 							NULL, 0);
503 			else
504 				ssif_info->done_handler(ssif_info, 0,
505 							ssif_info->i2c_data,
506 							result);
507 		}
508 	}
509 
510 	return 0;
511 }
512 
513 static void ssif_i2c_send(struct ssif_info *ssif_info,
514 			ssif_i2c_done handler,
515 			int read_write, int command,
516 			unsigned char *data, unsigned int size)
517 {
518 	ssif_info->done_handler = handler;
519 
520 	ssif_info->i2c_read_write = read_write;
521 	ssif_info->i2c_command = command;
522 	ssif_info->i2c_data = data;
523 	ssif_info->i2c_size = size;
524 	complete(&ssif_info->wake_thread);
525 }
526 
527 
528 static void msg_done_handler(struct ssif_info *ssif_info, int result,
529 			     unsigned char *data, unsigned int len);
530 
531 static void start_get(struct ssif_info *ssif_info)
532 {
533 	ssif_info->multi_pos = 0;
534 
535 	ssif_i2c_send(ssif_info, msg_done_handler, I2C_SMBUS_READ,
536 		  SSIF_IPMI_RESPONSE,
537 		  ssif_info->recv, I2C_SMBUS_BLOCK_DATA);
538 }
539 
540 static void start_resend(struct ssif_info *ssif_info);
541 
542 static void retry_timeout(struct timer_list *t)
543 {
544 	struct ssif_info *ssif_info = from_timer(ssif_info, t, retry_timer);
545 	unsigned long oflags, *flags;
546 	bool waiting, resend;
547 
548 	if (ssif_info->stopping)
549 		return;
550 
551 	flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
552 	resend = ssif_info->do_resend;
553 	ssif_info->do_resend = false;
554 	waiting = ssif_info->waiting_alert;
555 	ssif_info->waiting_alert = false;
556 	ipmi_ssif_unlock_cond(ssif_info, flags);
557 
558 	if (waiting)
559 		start_get(ssif_info);
560 	if (resend)
561 		start_resend(ssif_info);
562 }
563 
564 static void watch_timeout(struct timer_list *t)
565 {
566 	struct ssif_info *ssif_info = from_timer(ssif_info, t, watch_timer);
567 	unsigned long oflags, *flags;
568 
569 	if (ssif_info->stopping)
570 		return;
571 
572 	flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
573 	if (ssif_info->watch_timeout) {
574 		mod_timer(&ssif_info->watch_timer,
575 			  jiffies + ssif_info->watch_timeout);
576 		if (IS_SSIF_IDLE(ssif_info)) {
577 			start_flag_fetch(ssif_info, flags); /* Releases lock */
578 			return;
579 		}
580 		ssif_info->req_flags = true;
581 	}
582 	ipmi_ssif_unlock_cond(ssif_info, flags);
583 }
584 
585 static void ssif_alert(struct i2c_client *client, enum i2c_alert_protocol type,
586 		       unsigned int data)
587 {
588 	struct ssif_info *ssif_info = i2c_get_clientdata(client);
589 	unsigned long oflags, *flags;
590 	bool do_get = false;
591 
592 	if (type != I2C_PROTOCOL_SMBUS_ALERT)
593 		return;
594 
595 	ssif_inc_stat(ssif_info, alerts);
596 
597 	flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
598 	if (ssif_info->waiting_alert) {
599 		ssif_info->waiting_alert = false;
600 		del_timer(&ssif_info->retry_timer);
601 		do_get = true;
602 	} else if (ssif_info->curr_msg) {
603 		ssif_info->got_alert = true;
604 	}
605 	ipmi_ssif_unlock_cond(ssif_info, flags);
606 	if (do_get)
607 		start_get(ssif_info);
608 }
609 
610 static void msg_done_handler(struct ssif_info *ssif_info, int result,
611 			     unsigned char *data, unsigned int len)
612 {
613 	struct ipmi_smi_msg *msg;
614 	unsigned long oflags, *flags;
615 
616 	/*
617 	 * We are single-threaded here, so no need for a lock until we
618 	 * start messing with driver states or the queues.
619 	 */
620 
621 	if (result < 0) {
622 		ssif_info->retries_left--;
623 		if (ssif_info->retries_left > 0) {
624 			ssif_inc_stat(ssif_info, receive_retries);
625 
626 			flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
627 			ssif_info->waiting_alert = true;
628 			if (!ssif_info->stopping)
629 				mod_timer(&ssif_info->retry_timer,
630 					  jiffies + SSIF_MSG_JIFFIES);
631 			ipmi_ssif_unlock_cond(ssif_info, flags);
632 			return;
633 		}
634 
635 		ssif_inc_stat(ssif_info, receive_errors);
636 
637 		if  (ssif_info->ssif_debug & SSIF_DEBUG_MSG)
638 			dev_dbg(&ssif_info->client->dev,
639 				"%s: Error %d\n", __func__, result);
640 		len = 0;
641 		goto continue_op;
642 	}
643 
644 	if ((len > 1) && (ssif_info->multi_pos == 0)
645 				&& (data[0] == 0x00) && (data[1] == 0x01)) {
646 		/* Start of multi-part read.  Start the next transaction. */
647 		int i;
648 
649 		ssif_inc_stat(ssif_info, received_message_parts);
650 
651 		/* Remove the multi-part read marker. */
652 		len -= 2;
653 		data += 2;
654 		for (i = 0; i < len; i++)
655 			ssif_info->data[i] = data[i];
656 		ssif_info->multi_len = len;
657 		ssif_info->multi_pos = 1;
658 
659 		ssif_i2c_send(ssif_info, msg_done_handler, I2C_SMBUS_READ,
660 			 SSIF_IPMI_MULTI_PART_RESPONSE_MIDDLE,
661 			 ssif_info->recv, I2C_SMBUS_BLOCK_DATA);
662 		return;
663 	} else if (ssif_info->multi_pos) {
664 		/* Middle of multi-part read.  Start the next transaction. */
665 		int i;
666 		unsigned char blocknum;
667 
668 		if (len == 0) {
669 			result = -EIO;
670 			if (ssif_info->ssif_debug & SSIF_DEBUG_MSG)
671 				dev_dbg(&ssif_info->client->dev,
672 					"Middle message with no data\n");
673 
674 			goto continue_op;
675 		}
676 
677 		blocknum = data[0];
678 		len--;
679 		data++;
680 
681 		if (blocknum != 0xff && len != 31) {
682 		    /* All blocks but the last must have 31 data bytes. */
683 			result = -EIO;
684 			if (ssif_info->ssif_debug & SSIF_DEBUG_MSG)
685 				dev_dbg(&ssif_info->client->dev,
686 					"Received middle message <31\n");
687 
688 			goto continue_op;
689 		}
690 
691 		if (ssif_info->multi_len + len > IPMI_MAX_MSG_LENGTH) {
692 			/* Received message too big, abort the operation. */
693 			result = -E2BIG;
694 			if (ssif_info->ssif_debug & SSIF_DEBUG_MSG)
695 				dev_dbg(&ssif_info->client->dev,
696 					"Received message too big\n");
697 
698 			goto continue_op;
699 		}
700 
701 		for (i = 0; i < len; i++)
702 			ssif_info->data[i + ssif_info->multi_len] = data[i];
703 		ssif_info->multi_len += len;
704 		if (blocknum == 0xff) {
705 			/* End of read */
706 			len = ssif_info->multi_len;
707 			data = ssif_info->data;
708 		} else if (blocknum + 1 != ssif_info->multi_pos) {
709 			/*
710 			 * Out of sequence block, just abort.  Block
711 			 * numbers start at zero for the second block,
712 			 * but multi_pos starts at one, so the +1.
713 			 */
714 			if (ssif_info->ssif_debug & SSIF_DEBUG_MSG)
715 				dev_dbg(&ssif_info->client->dev,
716 					"Received message out of sequence, expected %u, got %u\n",
717 					ssif_info->multi_pos - 1, blocknum);
718 			result = -EIO;
719 		} else {
720 			ssif_inc_stat(ssif_info, received_message_parts);
721 
722 			ssif_info->multi_pos++;
723 
724 			ssif_i2c_send(ssif_info, msg_done_handler,
725 				  I2C_SMBUS_READ,
726 				  SSIF_IPMI_MULTI_PART_RESPONSE_MIDDLE,
727 				  ssif_info->recv,
728 				  I2C_SMBUS_BLOCK_DATA);
729 			return;
730 		}
731 	}
732 
733  continue_op:
734 	if (result < 0) {
735 		ssif_inc_stat(ssif_info, receive_errors);
736 	} else {
737 		ssif_inc_stat(ssif_info, received_messages);
738 		ssif_inc_stat(ssif_info, received_message_parts);
739 	}
740 
741 	if (ssif_info->ssif_debug & SSIF_DEBUG_STATE)
742 		dev_dbg(&ssif_info->client->dev,
743 			"DONE 1: state = %d, result=%d\n",
744 			ssif_info->ssif_state, result);
745 
746 	flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
747 	msg = ssif_info->curr_msg;
748 	if (msg) {
749 		if (data) {
750 			if (len > IPMI_MAX_MSG_LENGTH)
751 				len = IPMI_MAX_MSG_LENGTH;
752 			memcpy(msg->rsp, data, len);
753 		} else {
754 			len = 0;
755 		}
756 		msg->rsp_size = len;
757 		ssif_info->curr_msg = NULL;
758 	}
759 
760 	switch (ssif_info->ssif_state) {
761 	case SSIF_IDLE:
762 		ipmi_ssif_unlock_cond(ssif_info, flags);
763 		if (!msg)
764 			break;
765 
766 		if (result < 0)
767 			return_hosed_msg(ssif_info, msg);
768 		else
769 			deliver_recv_msg(ssif_info, msg);
770 		break;
771 
772 	case SSIF_GETTING_FLAGS:
773 		/* We got the flags from the SSIF, now handle them. */
774 		if ((result < 0) || (len < 4) || (data[2] != 0)) {
775 			/*
776 			 * Error fetching flags, or invalid length,
777 			 * just give up for now.
778 			 */
779 			ssif_info->ssif_state = SSIF_IDLE;
780 			ipmi_ssif_unlock_cond(ssif_info, flags);
781 			dev_warn(&ssif_info->client->dev,
782 				 "Error getting flags: %d %d, %x\n",
783 				 result, len, (len >= 3) ? data[2] : 0);
784 		} else if (data[0] != (IPMI_NETFN_APP_REQUEST | 1) << 2
785 			   || data[1] != IPMI_GET_MSG_FLAGS_CMD) {
786 			/*
787 			 * Don't abort here, maybe it was a queued
788 			 * response to a previous command.
789 			 */
790 			ipmi_ssif_unlock_cond(ssif_info, flags);
791 			dev_warn(&ssif_info->client->dev,
792 				 "Invalid response getting flags: %x %x\n",
793 				 data[0], data[1]);
794 		} else {
795 			ssif_inc_stat(ssif_info, flag_fetches);
796 			ssif_info->msg_flags = data[3];
797 			handle_flags(ssif_info, flags);
798 		}
799 		break;
800 
801 	case SSIF_CLEARING_FLAGS:
802 		/* We cleared the flags. */
803 		if ((result < 0) || (len < 3) || (data[2] != 0)) {
804 			/* Error clearing flags */
805 			dev_warn(&ssif_info->client->dev,
806 				 "Error clearing flags: %d %d, %x\n",
807 				 result, len, (len >= 3) ? data[2] : 0);
808 		} else if (data[0] != (IPMI_NETFN_APP_REQUEST | 1) << 2
809 			   || data[1] != IPMI_CLEAR_MSG_FLAGS_CMD) {
810 			dev_warn(&ssif_info->client->dev,
811 				 "Invalid response clearing flags: %x %x\n",
812 				 data[0], data[1]);
813 		}
814 		ssif_info->ssif_state = SSIF_IDLE;
815 		ipmi_ssif_unlock_cond(ssif_info, flags);
816 		break;
817 
818 	case SSIF_GETTING_EVENTS:
819 		if (!msg) {
820 			/* Should never happen, but just in case. */
821 			dev_warn(&ssif_info->client->dev,
822 				 "No message set while getting events\n");
823 			ipmi_ssif_unlock_cond(ssif_info, flags);
824 			break;
825 		}
826 
827 		if ((result < 0) || (len < 3) || (msg->rsp[2] != 0)) {
828 			/* Error getting event, probably done. */
829 			msg->done(msg);
830 
831 			/* Take off the event flag. */
832 			ssif_info->msg_flags &= ~EVENT_MSG_BUFFER_FULL;
833 			handle_flags(ssif_info, flags);
834 		} else if (msg->rsp[0] != (IPMI_NETFN_APP_REQUEST | 1) << 2
835 			   || msg->rsp[1] != IPMI_READ_EVENT_MSG_BUFFER_CMD) {
836 			dev_warn(&ssif_info->client->dev,
837 				 "Invalid response getting events: %x %x\n",
838 				 msg->rsp[0], msg->rsp[1]);
839 			msg->done(msg);
840 			/* Take off the event flag. */
841 			ssif_info->msg_flags &= ~EVENT_MSG_BUFFER_FULL;
842 			handle_flags(ssif_info, flags);
843 		} else {
844 			handle_flags(ssif_info, flags);
845 			ssif_inc_stat(ssif_info, events);
846 			deliver_recv_msg(ssif_info, msg);
847 		}
848 		break;
849 
850 	case SSIF_GETTING_MESSAGES:
851 		if (!msg) {
852 			/* Should never happen, but just in case. */
853 			dev_warn(&ssif_info->client->dev,
854 				 "No message set while getting messages\n");
855 			ipmi_ssif_unlock_cond(ssif_info, flags);
856 			break;
857 		}
858 
859 		if ((result < 0) || (len < 3) || (msg->rsp[2] != 0)) {
860 			/* Error getting event, probably done. */
861 			msg->done(msg);
862 
863 			/* Take off the msg flag. */
864 			ssif_info->msg_flags &= ~RECEIVE_MSG_AVAIL;
865 			handle_flags(ssif_info, flags);
866 		} else if (msg->rsp[0] != (IPMI_NETFN_APP_REQUEST | 1) << 2
867 			   || msg->rsp[1] != IPMI_GET_MSG_CMD) {
868 			dev_warn(&ssif_info->client->dev,
869 				 "Invalid response clearing flags: %x %x\n",
870 				 msg->rsp[0], msg->rsp[1]);
871 			msg->done(msg);
872 
873 			/* Take off the msg flag. */
874 			ssif_info->msg_flags &= ~RECEIVE_MSG_AVAIL;
875 			handle_flags(ssif_info, flags);
876 		} else {
877 			ssif_inc_stat(ssif_info, incoming_messages);
878 			handle_flags(ssif_info, flags);
879 			deliver_recv_msg(ssif_info, msg);
880 		}
881 		break;
882 
883 	default:
884 		/* Should never happen, but just in case. */
885 		dev_warn(&ssif_info->client->dev,
886 			 "Invalid state in message done handling: %d\n",
887 			 ssif_info->ssif_state);
888 		ipmi_ssif_unlock_cond(ssif_info, flags);
889 	}
890 
891 	flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
892 	if (IS_SSIF_IDLE(ssif_info) && !ssif_info->stopping) {
893 		if (ssif_info->req_events)
894 			start_event_fetch(ssif_info, flags);
895 		else if (ssif_info->req_flags)
896 			start_flag_fetch(ssif_info, flags);
897 		else
898 			start_next_msg(ssif_info, flags);
899 	} else
900 		ipmi_ssif_unlock_cond(ssif_info, flags);
901 
902 	if (ssif_info->ssif_debug & SSIF_DEBUG_STATE)
903 		dev_dbg(&ssif_info->client->dev,
904 			"DONE 2: state = %d.\n", ssif_info->ssif_state);
905 }
906 
907 static void msg_written_handler(struct ssif_info *ssif_info, int result,
908 				unsigned char *data, unsigned int len)
909 {
910 	/* We are single-threaded here, so no need for a lock. */
911 	if (result < 0) {
912 		ssif_info->retries_left--;
913 		if (ssif_info->retries_left > 0) {
914 			/*
915 			 * Wait the retry timeout time per the spec,
916 			 * then redo the send.
917 			 */
918 			ssif_info->do_resend = true;
919 			mod_timer(&ssif_info->retry_timer,
920 				  jiffies + SSIF_REQ_RETRY_JIFFIES);
921 			return;
922 		}
923 
924 		ssif_inc_stat(ssif_info, send_errors);
925 
926 		if (ssif_info->ssif_debug & SSIF_DEBUG_MSG)
927 			dev_dbg(&ssif_info->client->dev,
928 				"%s: Out of retries\n", __func__);
929 
930 		msg_done_handler(ssif_info, -EIO, NULL, 0);
931 		return;
932 	}
933 
934 	if (ssif_info->multi_data) {
935 		/*
936 		 * In the middle of a multi-data write.  See the comment
937 		 * in the SSIF_MULTI_n_PART case in the probe function
938 		 * for details on the intricacies of this.
939 		 */
940 		int left, to_write;
941 		unsigned char *data_to_send;
942 		unsigned char cmd;
943 
944 		ssif_inc_stat(ssif_info, sent_messages_parts);
945 
946 		left = ssif_info->multi_len - ssif_info->multi_pos;
947 		to_write = left;
948 		if (to_write > 32)
949 			to_write = 32;
950 		/* Length byte. */
951 		ssif_info->multi_data[ssif_info->multi_pos] = to_write;
952 		data_to_send = ssif_info->multi_data + ssif_info->multi_pos;
953 		ssif_info->multi_pos += to_write;
954 		cmd = SSIF_IPMI_MULTI_PART_REQUEST_MIDDLE;
955 		if (ssif_info->cmd8_works) {
956 			if (left == to_write) {
957 				cmd = SSIF_IPMI_MULTI_PART_REQUEST_END;
958 				ssif_info->multi_data = NULL;
959 			}
960 		} else if (to_write < 32) {
961 			ssif_info->multi_data = NULL;
962 		}
963 
964 		ssif_i2c_send(ssif_info, msg_written_handler,
965 			  I2C_SMBUS_WRITE, cmd,
966 			  data_to_send, I2C_SMBUS_BLOCK_DATA);
967 	} else {
968 		/* Ready to request the result. */
969 		unsigned long oflags, *flags;
970 
971 		ssif_inc_stat(ssif_info, sent_messages);
972 		ssif_inc_stat(ssif_info, sent_messages_parts);
973 
974 		flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
975 		if (ssif_info->got_alert) {
976 			/* The result is already ready, just start it. */
977 			ssif_info->got_alert = false;
978 			ipmi_ssif_unlock_cond(ssif_info, flags);
979 			start_get(ssif_info);
980 		} else {
981 			/* Wait a jiffie then request the next message */
982 			ssif_info->waiting_alert = true;
983 			ssif_info->retries_left = SSIF_RECV_RETRIES;
984 			if (!ssif_info->stopping)
985 				mod_timer(&ssif_info->retry_timer,
986 					  jiffies + SSIF_MSG_PART_JIFFIES);
987 			ipmi_ssif_unlock_cond(ssif_info, flags);
988 		}
989 	}
990 }
991 
992 static void start_resend(struct ssif_info *ssif_info)
993 {
994 	int command;
995 
996 	ssif_info->got_alert = false;
997 
998 	if (ssif_info->data_len > 32) {
999 		command = SSIF_IPMI_MULTI_PART_REQUEST_START;
1000 		ssif_info->multi_data = ssif_info->data;
1001 		ssif_info->multi_len = ssif_info->data_len;
1002 		/*
1003 		 * Subtle thing, this is 32, not 33, because we will
1004 		 * overwrite the thing at position 32 (which was just
1005 		 * transmitted) with the new length.
1006 		 */
1007 		ssif_info->multi_pos = 32;
1008 		ssif_info->data[0] = 32;
1009 	} else {
1010 		ssif_info->multi_data = NULL;
1011 		command = SSIF_IPMI_REQUEST;
1012 		ssif_info->data[0] = ssif_info->data_len;
1013 	}
1014 
1015 	ssif_i2c_send(ssif_info, msg_written_handler, I2C_SMBUS_WRITE,
1016 		   command, ssif_info->data, I2C_SMBUS_BLOCK_DATA);
1017 }
1018 
1019 static int start_send(struct ssif_info *ssif_info,
1020 		      unsigned char   *data,
1021 		      unsigned int    len)
1022 {
1023 	if (len > IPMI_MAX_MSG_LENGTH)
1024 		return -E2BIG;
1025 	if (len > ssif_info->max_xmit_msg_size)
1026 		return -E2BIG;
1027 
1028 	ssif_info->retries_left = SSIF_SEND_RETRIES;
1029 	memcpy(ssif_info->data + 1, data, len);
1030 	ssif_info->data_len = len;
1031 	start_resend(ssif_info);
1032 	return 0;
1033 }
1034 
1035 /* Must be called with the message lock held. */
1036 static void start_next_msg(struct ssif_info *ssif_info, unsigned long *flags)
1037 {
1038 	struct ipmi_smi_msg *msg;
1039 	unsigned long oflags;
1040 
1041  restart:
1042 	if (!IS_SSIF_IDLE(ssif_info)) {
1043 		ipmi_ssif_unlock_cond(ssif_info, flags);
1044 		return;
1045 	}
1046 
1047 	if (!ssif_info->waiting_msg) {
1048 		ssif_info->curr_msg = NULL;
1049 		ipmi_ssif_unlock_cond(ssif_info, flags);
1050 	} else {
1051 		int rv;
1052 
1053 		ssif_info->curr_msg = ssif_info->waiting_msg;
1054 		ssif_info->waiting_msg = NULL;
1055 		ipmi_ssif_unlock_cond(ssif_info, flags);
1056 		rv = start_send(ssif_info,
1057 				ssif_info->curr_msg->data,
1058 				ssif_info->curr_msg->data_size);
1059 		if (rv) {
1060 			msg = ssif_info->curr_msg;
1061 			ssif_info->curr_msg = NULL;
1062 			return_hosed_msg(ssif_info, msg);
1063 			flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
1064 			goto restart;
1065 		}
1066 	}
1067 }
1068 
1069 static void sender(void                *send_info,
1070 		   struct ipmi_smi_msg *msg)
1071 {
1072 	struct ssif_info *ssif_info = send_info;
1073 	unsigned long oflags, *flags;
1074 
1075 	BUG_ON(ssif_info->waiting_msg);
1076 	ssif_info->waiting_msg = msg;
1077 
1078 	flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
1079 	start_next_msg(ssif_info, flags);
1080 
1081 	if (ssif_info->ssif_debug & SSIF_DEBUG_TIMING) {
1082 		struct timespec64 t;
1083 
1084 		ktime_get_real_ts64(&t);
1085 		dev_dbg(&ssif_info->client->dev,
1086 			"**Enqueue %02x %02x: %lld.%6.6ld\n",
1087 			msg->data[0], msg->data[1],
1088 			(long long)t.tv_sec, (long)t.tv_nsec / NSEC_PER_USEC);
1089 	}
1090 }
1091 
1092 static int get_smi_info(void *send_info, struct ipmi_smi_info *data)
1093 {
1094 	struct ssif_info *ssif_info = send_info;
1095 
1096 	data->addr_src = ssif_info->addr_source;
1097 	data->dev = &ssif_info->client->dev;
1098 	data->addr_info = ssif_info->addr_info;
1099 	get_device(data->dev);
1100 
1101 	return 0;
1102 }
1103 
1104 /*
1105  * Upper layer wants us to request events.
1106  */
1107 static void request_events(void *send_info)
1108 {
1109 	struct ssif_info *ssif_info = send_info;
1110 	unsigned long oflags, *flags;
1111 
1112 	if (!ssif_info->has_event_buffer)
1113 		return;
1114 
1115 	flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
1116 	ssif_info->req_events = true;
1117 	ipmi_ssif_unlock_cond(ssif_info, flags);
1118 }
1119 
1120 /*
1121  * Upper layer is changing the flag saying whether we need to request
1122  * flags periodically or not.
1123  */
1124 static void ssif_set_need_watch(void *send_info, unsigned int watch_mask)
1125 {
1126 	struct ssif_info *ssif_info = send_info;
1127 	unsigned long oflags, *flags;
1128 	long timeout = 0;
1129 
1130 	if (watch_mask & IPMI_WATCH_MASK_CHECK_MESSAGES)
1131 		timeout = SSIF_WATCH_MSG_TIMEOUT;
1132 	else if (watch_mask)
1133 		timeout = SSIF_WATCH_WATCHDOG_TIMEOUT;
1134 
1135 	flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
1136 	if (timeout != ssif_info->watch_timeout) {
1137 		ssif_info->watch_timeout = timeout;
1138 		if (ssif_info->watch_timeout)
1139 			mod_timer(&ssif_info->watch_timer,
1140 				  jiffies + ssif_info->watch_timeout);
1141 	}
1142 	ipmi_ssif_unlock_cond(ssif_info, flags);
1143 }
1144 
1145 static int ssif_start_processing(void            *send_info,
1146 				 struct ipmi_smi *intf)
1147 {
1148 	struct ssif_info *ssif_info = send_info;
1149 
1150 	ssif_info->intf = intf;
1151 
1152 	return 0;
1153 }
1154 
1155 #define MAX_SSIF_BMCS 4
1156 
1157 static unsigned short addr[MAX_SSIF_BMCS];
1158 static int num_addrs;
1159 module_param_array(addr, ushort, &num_addrs, 0);
1160 MODULE_PARM_DESC(addr, "The addresses to scan for IPMI BMCs on the SSIFs.");
1161 
1162 static char *adapter_name[MAX_SSIF_BMCS];
1163 static int num_adapter_names;
1164 module_param_array(adapter_name, charp, &num_adapter_names, 0);
1165 MODULE_PARM_DESC(adapter_name, "The string name of the I2C device that has the BMC.  By default all devices are scanned.");
1166 
1167 static int slave_addrs[MAX_SSIF_BMCS];
1168 static int num_slave_addrs;
1169 module_param_array(slave_addrs, int, &num_slave_addrs, 0);
1170 MODULE_PARM_DESC(slave_addrs,
1171 		 "The default IPMB slave address for the controller.");
1172 
1173 static bool alerts_broken;
1174 module_param(alerts_broken, bool, 0);
1175 MODULE_PARM_DESC(alerts_broken, "Don't enable alerts for the controller.");
1176 
1177 /*
1178  * Bit 0 enables message debugging, bit 1 enables state debugging, and
1179  * bit 2 enables timing debugging.  This is an array indexed by
1180  * interface number"
1181  */
1182 static int dbg[MAX_SSIF_BMCS];
1183 static int num_dbg;
1184 module_param_array(dbg, int, &num_dbg, 0);
1185 MODULE_PARM_DESC(dbg, "Turn on debugging.");
1186 
1187 static bool ssif_dbg_probe;
1188 module_param_named(dbg_probe, ssif_dbg_probe, bool, 0);
1189 MODULE_PARM_DESC(dbg_probe, "Enable debugging of probing of adapters.");
1190 
1191 static bool ssif_tryacpi = true;
1192 module_param_named(tryacpi, ssif_tryacpi, bool, 0);
1193 MODULE_PARM_DESC(tryacpi, "Setting this to zero will disable the default scan of the interfaces identified via ACPI");
1194 
1195 static bool ssif_trydmi = true;
1196 module_param_named(trydmi, ssif_trydmi, bool, 0);
1197 MODULE_PARM_DESC(trydmi, "Setting this to zero will disable the default scan of the interfaces identified via DMI (SMBIOS)");
1198 
1199 static DEFINE_MUTEX(ssif_infos_mutex);
1200 static LIST_HEAD(ssif_infos);
1201 
1202 #define IPMI_SSIF_ATTR(name) \
1203 static ssize_t ipmi_##name##_show(struct device *dev,			\
1204 				  struct device_attribute *attr,	\
1205 				  char *buf)				\
1206 {									\
1207 	struct ssif_info *ssif_info = dev_get_drvdata(dev);		\
1208 									\
1209 	return sysfs_emit(buf, "%u\n", ssif_get_stat(ssif_info, name));\
1210 }									\
1211 static DEVICE_ATTR(name, S_IRUGO, ipmi_##name##_show, NULL)
1212 
1213 static ssize_t ipmi_type_show(struct device *dev,
1214 			      struct device_attribute *attr,
1215 			      char *buf)
1216 {
1217 	return sysfs_emit(buf, "ssif\n");
1218 }
1219 static DEVICE_ATTR(type, S_IRUGO, ipmi_type_show, NULL);
1220 
1221 IPMI_SSIF_ATTR(sent_messages);
1222 IPMI_SSIF_ATTR(sent_messages_parts);
1223 IPMI_SSIF_ATTR(send_retries);
1224 IPMI_SSIF_ATTR(send_errors);
1225 IPMI_SSIF_ATTR(received_messages);
1226 IPMI_SSIF_ATTR(received_message_parts);
1227 IPMI_SSIF_ATTR(receive_retries);
1228 IPMI_SSIF_ATTR(receive_errors);
1229 IPMI_SSIF_ATTR(flag_fetches);
1230 IPMI_SSIF_ATTR(hosed);
1231 IPMI_SSIF_ATTR(events);
1232 IPMI_SSIF_ATTR(watchdog_pretimeouts);
1233 IPMI_SSIF_ATTR(alerts);
1234 
1235 static struct attribute *ipmi_ssif_dev_attrs[] = {
1236 	&dev_attr_type.attr,
1237 	&dev_attr_sent_messages.attr,
1238 	&dev_attr_sent_messages_parts.attr,
1239 	&dev_attr_send_retries.attr,
1240 	&dev_attr_send_errors.attr,
1241 	&dev_attr_received_messages.attr,
1242 	&dev_attr_received_message_parts.attr,
1243 	&dev_attr_receive_retries.attr,
1244 	&dev_attr_receive_errors.attr,
1245 	&dev_attr_flag_fetches.attr,
1246 	&dev_attr_hosed.attr,
1247 	&dev_attr_events.attr,
1248 	&dev_attr_watchdog_pretimeouts.attr,
1249 	&dev_attr_alerts.attr,
1250 	NULL
1251 };
1252 
1253 static const struct attribute_group ipmi_ssif_dev_attr_group = {
1254 	.attrs		= ipmi_ssif_dev_attrs,
1255 };
1256 
1257 static void shutdown_ssif(void *send_info)
1258 {
1259 	struct ssif_info *ssif_info = send_info;
1260 
1261 	device_remove_group(&ssif_info->client->dev, &ipmi_ssif_dev_attr_group);
1262 	dev_set_drvdata(&ssif_info->client->dev, NULL);
1263 
1264 	/* make sure the driver is not looking for flags any more. */
1265 	while (ssif_info->ssif_state != SSIF_IDLE)
1266 		schedule_timeout(1);
1267 
1268 	ssif_info->stopping = true;
1269 	del_timer_sync(&ssif_info->watch_timer);
1270 	del_timer_sync(&ssif_info->retry_timer);
1271 	if (ssif_info->thread) {
1272 		complete(&ssif_info->wake_thread);
1273 		kthread_stop(ssif_info->thread);
1274 	}
1275 }
1276 
1277 static void ssif_remove(struct i2c_client *client)
1278 {
1279 	struct ssif_info *ssif_info = i2c_get_clientdata(client);
1280 	struct ssif_addr_info *addr_info;
1281 
1282 	if (!ssif_info)
1283 		return;
1284 
1285 	/*
1286 	 * After this point, we won't deliver anything asychronously
1287 	 * to the message handler.  We can unregister ourself.
1288 	 */
1289 	ipmi_unregister_smi(ssif_info->intf);
1290 
1291 	list_for_each_entry(addr_info, &ssif_infos, link) {
1292 		if (addr_info->client == client) {
1293 			addr_info->client = NULL;
1294 			break;
1295 		}
1296 	}
1297 
1298 	kfree(ssif_info);
1299 }
1300 
1301 static int read_response(struct i2c_client *client, unsigned char *resp)
1302 {
1303 	int ret = -ENODEV, retry_cnt = SSIF_RECV_RETRIES;
1304 
1305 	while (retry_cnt > 0) {
1306 		ret = i2c_smbus_read_block_data(client, SSIF_IPMI_RESPONSE,
1307 						resp);
1308 		if (ret > 0)
1309 			break;
1310 		msleep(SSIF_MSG_MSEC);
1311 		retry_cnt--;
1312 		if (retry_cnt <= 0)
1313 			break;
1314 	}
1315 
1316 	return ret;
1317 }
1318 
1319 static int do_cmd(struct i2c_client *client, int len, unsigned char *msg,
1320 		  int *resp_len, unsigned char *resp)
1321 {
1322 	int retry_cnt;
1323 	int ret;
1324 
1325 	retry_cnt = SSIF_SEND_RETRIES;
1326  retry1:
1327 	ret = i2c_smbus_write_block_data(client, SSIF_IPMI_REQUEST, len, msg);
1328 	if (ret) {
1329 		retry_cnt--;
1330 		if (retry_cnt > 0) {
1331 			msleep(SSIF_REQ_RETRY_MSEC);
1332 			goto retry1;
1333 		}
1334 		return -ENODEV;
1335 	}
1336 
1337 	ret = read_response(client, resp);
1338 	if (ret > 0) {
1339 		/* Validate that the response is correct. */
1340 		if (ret < 3 ||
1341 		    (resp[0] != (msg[0] | (1 << 2))) ||
1342 		    (resp[1] != msg[1]))
1343 			ret = -EINVAL;
1344 		else if (ret > IPMI_MAX_MSG_LENGTH) {
1345 			ret = -E2BIG;
1346 		} else {
1347 			*resp_len = ret;
1348 			ret = 0;
1349 		}
1350 	}
1351 
1352 	return ret;
1353 }
1354 
1355 static int ssif_detect(struct i2c_client *client, struct i2c_board_info *info)
1356 {
1357 	unsigned char *resp;
1358 	unsigned char msg[3];
1359 	int           rv;
1360 	int           len;
1361 
1362 	resp = kmalloc(IPMI_MAX_MSG_LENGTH, GFP_KERNEL);
1363 	if (!resp)
1364 		return -ENOMEM;
1365 
1366 	/* Do a Get Device ID command, since it is required. */
1367 	msg[0] = IPMI_NETFN_APP_REQUEST << 2;
1368 	msg[1] = IPMI_GET_DEVICE_ID_CMD;
1369 	rv = do_cmd(client, 2, msg, &len, resp);
1370 	if (rv)
1371 		rv = -ENODEV;
1372 	else
1373 		strscpy(info->type, DEVICE_NAME, I2C_NAME_SIZE);
1374 	kfree(resp);
1375 	return rv;
1376 }
1377 
1378 static int strcmp_nospace(char *s1, char *s2)
1379 {
1380 	while (*s1 && *s2) {
1381 		while (isspace(*s1))
1382 			s1++;
1383 		while (isspace(*s2))
1384 			s2++;
1385 		if (*s1 > *s2)
1386 			return 1;
1387 		if (*s1 < *s2)
1388 			return -1;
1389 		s1++;
1390 		s2++;
1391 	}
1392 	return 0;
1393 }
1394 
1395 static struct ssif_addr_info *ssif_info_find(unsigned short addr,
1396 					     char *adapter_name,
1397 					     bool match_null_name)
1398 {
1399 	struct ssif_addr_info *info, *found = NULL;
1400 
1401 restart:
1402 	list_for_each_entry(info, &ssif_infos, link) {
1403 		if (info->binfo.addr == addr) {
1404 			if (info->addr_src == SI_SMBIOS)
1405 				info->adapter_name = kstrdup(adapter_name,
1406 							     GFP_KERNEL);
1407 
1408 			if (info->adapter_name || adapter_name) {
1409 				if (!info->adapter_name != !adapter_name) {
1410 					/* One is NULL and one is not */
1411 					continue;
1412 				}
1413 				if (adapter_name &&
1414 				    strcmp_nospace(info->adapter_name,
1415 						   adapter_name))
1416 					/* Names do not match */
1417 					continue;
1418 			}
1419 			found = info;
1420 			break;
1421 		}
1422 	}
1423 
1424 	if (!found && match_null_name) {
1425 		/* Try to get an exact match first, then try with a NULL name */
1426 		adapter_name = NULL;
1427 		match_null_name = false;
1428 		goto restart;
1429 	}
1430 
1431 	return found;
1432 }
1433 
1434 static bool check_acpi(struct ssif_info *ssif_info, struct device *dev)
1435 {
1436 #ifdef CONFIG_ACPI
1437 	acpi_handle acpi_handle;
1438 
1439 	acpi_handle = ACPI_HANDLE(dev);
1440 	if (acpi_handle) {
1441 		ssif_info->addr_source = SI_ACPI;
1442 		ssif_info->addr_info.acpi_info.acpi_handle = acpi_handle;
1443 		request_module("acpi_ipmi");
1444 		return true;
1445 	}
1446 #endif
1447 	return false;
1448 }
1449 
1450 static int find_slave_address(struct i2c_client *client, int slave_addr)
1451 {
1452 #ifdef CONFIG_IPMI_DMI_DECODE
1453 	if (!slave_addr)
1454 		slave_addr = ipmi_dmi_get_slave_addr(
1455 			SI_TYPE_INVALID,
1456 			i2c_adapter_id(client->adapter),
1457 			client->addr);
1458 #endif
1459 
1460 	return slave_addr;
1461 }
1462 
1463 static int start_multipart_test(struct i2c_client *client,
1464 				unsigned char *msg, bool do_middle)
1465 {
1466 	int retry_cnt = SSIF_SEND_RETRIES, ret;
1467 
1468 retry_write:
1469 	ret = i2c_smbus_write_block_data(client,
1470 					 SSIF_IPMI_MULTI_PART_REQUEST_START,
1471 					 32, msg);
1472 	if (ret) {
1473 		retry_cnt--;
1474 		if (retry_cnt > 0) {
1475 			msleep(SSIF_REQ_RETRY_MSEC);
1476 			goto retry_write;
1477 		}
1478 		dev_err(&client->dev, "Could not write multi-part start, though the BMC said it could handle it.  Just limit sends to one part.\n");
1479 		return ret;
1480 	}
1481 
1482 	if (!do_middle)
1483 		return 0;
1484 
1485 	ret = i2c_smbus_write_block_data(client,
1486 					 SSIF_IPMI_MULTI_PART_REQUEST_MIDDLE,
1487 					 32, msg + 32);
1488 	if (ret) {
1489 		dev_err(&client->dev, "Could not write multi-part middle, though the BMC said it could handle it.  Just limit sends to one part.\n");
1490 		return ret;
1491 	}
1492 
1493 	return 0;
1494 }
1495 
1496 static void test_multipart_messages(struct i2c_client *client,
1497 				    struct ssif_info *ssif_info,
1498 				    unsigned char *resp)
1499 {
1500 	unsigned char msg[65];
1501 	int ret;
1502 	bool do_middle;
1503 
1504 	if (ssif_info->max_xmit_msg_size <= 32)
1505 		return;
1506 
1507 	do_middle = ssif_info->max_xmit_msg_size > 63;
1508 
1509 	memset(msg, 0, sizeof(msg));
1510 	msg[0] = IPMI_NETFN_APP_REQUEST << 2;
1511 	msg[1] = IPMI_GET_DEVICE_ID_CMD;
1512 
1513 	/*
1514 	 * The specification is all messed up dealing with sending
1515 	 * multi-part messages.  Per what the specification says, it
1516 	 * is impossible to send a message that is a multiple of 32
1517 	 * bytes, except for 32 itself.  It talks about a "start"
1518 	 * transaction (cmd=6) that must be 32 bytes, "middle"
1519 	 * transaction (cmd=7) that must be 32 bytes, and an "end"
1520 	 * transaction.  The "end" transaction is shown as cmd=7 in
1521 	 * the text, but if that's the case there is no way to
1522 	 * differentiate between a middle and end part except the
1523 	 * length being less than 32.  But there is a table at the far
1524 	 * end of the section (that I had never noticed until someone
1525 	 * pointed it out to me) that mentions it as cmd=8.
1526 	 *
1527 	 * After some thought, I think the example is wrong and the
1528 	 * end transaction should be cmd=8.  But some systems don't
1529 	 * implement cmd=8, they use a zero-length end transaction,
1530 	 * even though that violates the SMBus specification.
1531 	 *
1532 	 * So, to work around this, this code tests if cmd=8 works.
1533 	 * If it does, then we use that.  If not, it tests zero-
1534 	 * byte end transactions.  If that works, good.  If not,
1535 	 * we only allow 63-byte transactions max.
1536 	 */
1537 
1538 	ret = start_multipart_test(client, msg, do_middle);
1539 	if (ret)
1540 		goto out_no_multi_part;
1541 
1542 	ret = i2c_smbus_write_block_data(client,
1543 					 SSIF_IPMI_MULTI_PART_REQUEST_END,
1544 					 1, msg + 64);
1545 
1546 	if (!ret)
1547 		ret = read_response(client, resp);
1548 
1549 	if (ret > 0) {
1550 		/* End transactions work, we are good. */
1551 		ssif_info->cmd8_works = true;
1552 		return;
1553 	}
1554 
1555 	ret = start_multipart_test(client, msg, do_middle);
1556 	if (ret) {
1557 		dev_err(&client->dev, "Second multipart test failed.\n");
1558 		goto out_no_multi_part;
1559 	}
1560 
1561 	ret = i2c_smbus_write_block_data(client,
1562 					 SSIF_IPMI_MULTI_PART_REQUEST_MIDDLE,
1563 					 0, msg + 64);
1564 	if (!ret)
1565 		ret = read_response(client, resp);
1566 	if (ret > 0)
1567 		/* Zero-size end parts work, use those. */
1568 		return;
1569 
1570 	/* Limit to 63 bytes and use a short middle command to mark the end. */
1571 	if (ssif_info->max_xmit_msg_size > 63)
1572 		ssif_info->max_xmit_msg_size = 63;
1573 	return;
1574 
1575 out_no_multi_part:
1576 	ssif_info->max_xmit_msg_size = 32;
1577 	return;
1578 }
1579 
1580 /*
1581  * Global enables we care about.
1582  */
1583 #define GLOBAL_ENABLES_MASK (IPMI_BMC_EVT_MSG_BUFF | IPMI_BMC_RCV_MSG_INTR | \
1584 			     IPMI_BMC_EVT_MSG_INTR)
1585 
1586 static void ssif_remove_dup(struct i2c_client *client)
1587 {
1588 	struct ssif_info *ssif_info = i2c_get_clientdata(client);
1589 
1590 	ipmi_unregister_smi(ssif_info->intf);
1591 	kfree(ssif_info);
1592 }
1593 
1594 static int ssif_add_infos(struct i2c_client *client)
1595 {
1596 	struct ssif_addr_info *info;
1597 
1598 	info = kzalloc(sizeof(*info), GFP_KERNEL);
1599 	if (!info)
1600 		return -ENOMEM;
1601 	info->addr_src = SI_ACPI;
1602 	info->client = client;
1603 	info->adapter_name = kstrdup(client->adapter->name, GFP_KERNEL);
1604 	info->binfo.addr = client->addr;
1605 	list_add_tail(&info->link, &ssif_infos);
1606 	return 0;
1607 }
1608 
1609 /*
1610  * Prefer ACPI over SMBIOS, if both are available.
1611  * So if we get an ACPI interface and have already registered a SMBIOS
1612  * interface at the same address, remove the SMBIOS and add the ACPI one.
1613  */
1614 static int ssif_check_and_remove(struct i2c_client *client,
1615 			      struct ssif_info *ssif_info)
1616 {
1617 	struct ssif_addr_info *info;
1618 
1619 	list_for_each_entry(info, &ssif_infos, link) {
1620 		if (!info->client)
1621 			return 0;
1622 		if (!strcmp(info->adapter_name, client->adapter->name) &&
1623 		    info->binfo.addr == client->addr) {
1624 			if (info->addr_src == SI_ACPI)
1625 				return -EEXIST;
1626 
1627 			if (ssif_info->addr_source == SI_ACPI &&
1628 			    info->addr_src == SI_SMBIOS) {
1629 				dev_info(&client->dev,
1630 					 "Removing %s-specified SSIF interface in favor of ACPI\n",
1631 					 ipmi_addr_src_to_str(info->addr_src));
1632 				ssif_remove_dup(info->client);
1633 				return 0;
1634 			}
1635 		}
1636 	}
1637 	return 0;
1638 }
1639 
1640 static int ssif_probe(struct i2c_client *client)
1641 {
1642 	unsigned char     msg[3];
1643 	unsigned char     *resp;
1644 	struct ssif_info   *ssif_info;
1645 	int               rv = 0;
1646 	int               len = 0;
1647 	int               i;
1648 	u8		  slave_addr = 0;
1649 	struct ssif_addr_info *addr_info = NULL;
1650 
1651 	mutex_lock(&ssif_infos_mutex);
1652 	resp = kmalloc(IPMI_MAX_MSG_LENGTH, GFP_KERNEL);
1653 	if (!resp) {
1654 		mutex_unlock(&ssif_infos_mutex);
1655 		return -ENOMEM;
1656 	}
1657 
1658 	ssif_info = kzalloc(sizeof(*ssif_info), GFP_KERNEL);
1659 	if (!ssif_info) {
1660 		kfree(resp);
1661 		mutex_unlock(&ssif_infos_mutex);
1662 		return -ENOMEM;
1663 	}
1664 
1665 	if (!check_acpi(ssif_info, &client->dev)) {
1666 		addr_info = ssif_info_find(client->addr, client->adapter->name,
1667 					   true);
1668 		if (!addr_info) {
1669 			/* Must have come in through sysfs. */
1670 			ssif_info->addr_source = SI_HOTMOD;
1671 		} else {
1672 			ssif_info->addr_source = addr_info->addr_src;
1673 			ssif_info->ssif_debug = addr_info->debug;
1674 			ssif_info->addr_info = addr_info->addr_info;
1675 			addr_info->client = client;
1676 			slave_addr = addr_info->slave_addr;
1677 		}
1678 	}
1679 
1680 	ssif_info->client = client;
1681 	i2c_set_clientdata(client, ssif_info);
1682 
1683 	rv = ssif_check_and_remove(client, ssif_info);
1684 	/* If rv is 0 and addr source is not SI_ACPI, continue probing */
1685 	if (!rv && ssif_info->addr_source == SI_ACPI) {
1686 		rv = ssif_add_infos(client);
1687 		if (rv) {
1688 			dev_err(&client->dev, "Out of memory!, exiting ..\n");
1689 			goto out;
1690 		}
1691 	} else if (rv) {
1692 		dev_err(&client->dev, "Not probing, Interface already present\n");
1693 		goto out;
1694 	}
1695 
1696 	slave_addr = find_slave_address(client, slave_addr);
1697 
1698 	dev_info(&client->dev,
1699 		 "Trying %s-specified SSIF interface at i2c address 0x%x, adapter %s, slave address 0x%x\n",
1700 		ipmi_addr_src_to_str(ssif_info->addr_source),
1701 		client->addr, client->adapter->name, slave_addr);
1702 
1703 	/* Now check for system interface capabilities */
1704 	msg[0] = IPMI_NETFN_APP_REQUEST << 2;
1705 	msg[1] = IPMI_GET_SYSTEM_INTERFACE_CAPABILITIES_CMD;
1706 	msg[2] = 0; /* SSIF */
1707 	rv = do_cmd(client, 3, msg, &len, resp);
1708 	if (!rv && (len >= 3) && (resp[2] == 0)) {
1709 		if (len < 7) {
1710 			if (ssif_dbg_probe)
1711 				dev_dbg(&ssif_info->client->dev,
1712 					"SSIF info too short: %d\n", len);
1713 			goto no_support;
1714 		}
1715 
1716 		/* Got a good SSIF response, handle it. */
1717 		ssif_info->max_xmit_msg_size = resp[5];
1718 		ssif_info->max_recv_msg_size = resp[6];
1719 		ssif_info->multi_support = (resp[4] >> 6) & 0x3;
1720 		ssif_info->supports_pec = (resp[4] >> 3) & 0x1;
1721 
1722 		/* Sanitize the data */
1723 		switch (ssif_info->multi_support) {
1724 		case SSIF_NO_MULTI:
1725 			if (ssif_info->max_xmit_msg_size > 32)
1726 				ssif_info->max_xmit_msg_size = 32;
1727 			if (ssif_info->max_recv_msg_size > 32)
1728 				ssif_info->max_recv_msg_size = 32;
1729 			break;
1730 
1731 		case SSIF_MULTI_2_PART:
1732 			if (ssif_info->max_xmit_msg_size > 63)
1733 				ssif_info->max_xmit_msg_size = 63;
1734 			if (ssif_info->max_recv_msg_size > 62)
1735 				ssif_info->max_recv_msg_size = 62;
1736 			break;
1737 
1738 		case SSIF_MULTI_n_PART:
1739 			/* We take whatever size given, but do some testing. */
1740 			break;
1741 
1742 		default:
1743 			/* Data is not sane, just give up. */
1744 			goto no_support;
1745 		}
1746 	} else {
1747  no_support:
1748 		/* Assume no multi-part or PEC support */
1749 		dev_info(&ssif_info->client->dev,
1750 			 "Error fetching SSIF: %d %d %2.2x, your system probably doesn't support this command so using defaults\n",
1751 			rv, len, resp[2]);
1752 
1753 		ssif_info->max_xmit_msg_size = 32;
1754 		ssif_info->max_recv_msg_size = 32;
1755 		ssif_info->multi_support = SSIF_NO_MULTI;
1756 		ssif_info->supports_pec = 0;
1757 	}
1758 
1759 	test_multipart_messages(client, ssif_info, resp);
1760 
1761 	/* Make sure the NMI timeout is cleared. */
1762 	msg[0] = IPMI_NETFN_APP_REQUEST << 2;
1763 	msg[1] = IPMI_CLEAR_MSG_FLAGS_CMD;
1764 	msg[2] = WDT_PRE_TIMEOUT_INT;
1765 	rv = do_cmd(client, 3, msg, &len, resp);
1766 	if (rv || (len < 3) || (resp[2] != 0))
1767 		dev_warn(&ssif_info->client->dev,
1768 			 "Unable to clear message flags: %d %d %2.2x\n",
1769 			 rv, len, resp[2]);
1770 
1771 	/* Attempt to enable the event buffer. */
1772 	msg[0] = IPMI_NETFN_APP_REQUEST << 2;
1773 	msg[1] = IPMI_GET_BMC_GLOBAL_ENABLES_CMD;
1774 	rv = do_cmd(client, 2, msg, &len, resp);
1775 	if (rv || (len < 4) || (resp[2] != 0)) {
1776 		dev_warn(&ssif_info->client->dev,
1777 			 "Error getting global enables: %d %d %2.2x\n",
1778 			 rv, len, resp[2]);
1779 		rv = 0; /* Not fatal */
1780 		goto found;
1781 	}
1782 
1783 	ssif_info->global_enables = resp[3];
1784 
1785 	if (resp[3] & IPMI_BMC_EVT_MSG_BUFF) {
1786 		ssif_info->has_event_buffer = true;
1787 		/* buffer is already enabled, nothing to do. */
1788 		goto found;
1789 	}
1790 
1791 	msg[0] = IPMI_NETFN_APP_REQUEST << 2;
1792 	msg[1] = IPMI_SET_BMC_GLOBAL_ENABLES_CMD;
1793 	msg[2] = ssif_info->global_enables | IPMI_BMC_EVT_MSG_BUFF;
1794 	rv = do_cmd(client, 3, msg, &len, resp);
1795 	if (rv || (len < 2)) {
1796 		dev_warn(&ssif_info->client->dev,
1797 			 "Error setting global enables: %d %d %2.2x\n",
1798 			 rv, len, resp[2]);
1799 		rv = 0; /* Not fatal */
1800 		goto found;
1801 	}
1802 
1803 	if (resp[2] == 0) {
1804 		/* A successful return means the event buffer is supported. */
1805 		ssif_info->has_event_buffer = true;
1806 		ssif_info->global_enables |= IPMI_BMC_EVT_MSG_BUFF;
1807 	}
1808 
1809 	/* Some systems don't behave well if you enable alerts. */
1810 	if (alerts_broken)
1811 		goto found;
1812 
1813 	msg[0] = IPMI_NETFN_APP_REQUEST << 2;
1814 	msg[1] = IPMI_SET_BMC_GLOBAL_ENABLES_CMD;
1815 	msg[2] = ssif_info->global_enables | IPMI_BMC_RCV_MSG_INTR;
1816 	rv = do_cmd(client, 3, msg, &len, resp);
1817 	if (rv || (len < 2)) {
1818 		dev_warn(&ssif_info->client->dev,
1819 			 "Error setting global enables: %d %d %2.2x\n",
1820 			 rv, len, resp[2]);
1821 		rv = 0; /* Not fatal */
1822 		goto found;
1823 	}
1824 
1825 	if (resp[2] == 0) {
1826 		/* A successful return means the alert is supported. */
1827 		ssif_info->supports_alert = true;
1828 		ssif_info->global_enables |= IPMI_BMC_RCV_MSG_INTR;
1829 	}
1830 
1831  found:
1832 	if (ssif_dbg_probe) {
1833 		dev_dbg(&ssif_info->client->dev,
1834 		       "%s: i2c_probe found device at i2c address %x\n",
1835 		       __func__, client->addr);
1836 	}
1837 
1838 	spin_lock_init(&ssif_info->lock);
1839 	ssif_info->ssif_state = SSIF_IDLE;
1840 	timer_setup(&ssif_info->retry_timer, retry_timeout, 0);
1841 	timer_setup(&ssif_info->watch_timer, watch_timeout, 0);
1842 
1843 	for (i = 0; i < SSIF_NUM_STATS; i++)
1844 		atomic_set(&ssif_info->stats[i], 0);
1845 
1846 	if (ssif_info->supports_pec)
1847 		ssif_info->client->flags |= I2C_CLIENT_PEC;
1848 
1849 	ssif_info->handlers.owner = THIS_MODULE;
1850 	ssif_info->handlers.start_processing = ssif_start_processing;
1851 	ssif_info->handlers.shutdown = shutdown_ssif;
1852 	ssif_info->handlers.get_smi_info = get_smi_info;
1853 	ssif_info->handlers.sender = sender;
1854 	ssif_info->handlers.request_events = request_events;
1855 	ssif_info->handlers.set_need_watch = ssif_set_need_watch;
1856 
1857 	{
1858 		unsigned int thread_num;
1859 
1860 		thread_num = ((i2c_adapter_id(ssif_info->client->adapter)
1861 			       << 8) |
1862 			      ssif_info->client->addr);
1863 		init_completion(&ssif_info->wake_thread);
1864 		ssif_info->thread = kthread_run(ipmi_ssif_thread, ssif_info,
1865 					       "kssif%4.4x", thread_num);
1866 		if (IS_ERR(ssif_info->thread)) {
1867 			rv = PTR_ERR(ssif_info->thread);
1868 			dev_notice(&ssif_info->client->dev,
1869 				   "Could not start kernel thread: error %d\n",
1870 				   rv);
1871 			goto out;
1872 		}
1873 	}
1874 
1875 	dev_set_drvdata(&ssif_info->client->dev, ssif_info);
1876 	rv = device_add_group(&ssif_info->client->dev,
1877 			      &ipmi_ssif_dev_attr_group);
1878 	if (rv) {
1879 		dev_err(&ssif_info->client->dev,
1880 			"Unable to add device attributes: error %d\n",
1881 			rv);
1882 		goto out;
1883 	}
1884 
1885 	rv = ipmi_register_smi(&ssif_info->handlers,
1886 			       ssif_info,
1887 			       &ssif_info->client->dev,
1888 			       slave_addr);
1889 	if (rv) {
1890 		dev_err(&ssif_info->client->dev,
1891 			"Unable to register device: error %d\n", rv);
1892 		goto out_remove_attr;
1893 	}
1894 
1895  out:
1896 	if (rv) {
1897 		if (addr_info)
1898 			addr_info->client = NULL;
1899 
1900 		dev_err(&ssif_info->client->dev,
1901 			"Unable to start IPMI SSIF: %d\n", rv);
1902 		i2c_set_clientdata(client, NULL);
1903 		kfree(ssif_info);
1904 	}
1905 	kfree(resp);
1906 	mutex_unlock(&ssif_infos_mutex);
1907 	return rv;
1908 
1909 out_remove_attr:
1910 	device_remove_group(&ssif_info->client->dev, &ipmi_ssif_dev_attr_group);
1911 	dev_set_drvdata(&ssif_info->client->dev, NULL);
1912 	goto out;
1913 }
1914 
1915 static int new_ssif_client(int addr, char *adapter_name,
1916 			   int debug, int slave_addr,
1917 			   enum ipmi_addr_src addr_src,
1918 			   struct device *dev)
1919 {
1920 	struct ssif_addr_info *addr_info;
1921 	int rv = 0;
1922 
1923 	mutex_lock(&ssif_infos_mutex);
1924 	if (ssif_info_find(addr, adapter_name, false)) {
1925 		rv = -EEXIST;
1926 		goto out_unlock;
1927 	}
1928 
1929 	addr_info = kzalloc(sizeof(*addr_info), GFP_KERNEL);
1930 	if (!addr_info) {
1931 		rv = -ENOMEM;
1932 		goto out_unlock;
1933 	}
1934 
1935 	if (adapter_name) {
1936 		addr_info->adapter_name = kstrdup(adapter_name, GFP_KERNEL);
1937 		if (!addr_info->adapter_name) {
1938 			kfree(addr_info);
1939 			rv = -ENOMEM;
1940 			goto out_unlock;
1941 		}
1942 	}
1943 
1944 	strncpy(addr_info->binfo.type, DEVICE_NAME,
1945 		sizeof(addr_info->binfo.type));
1946 	addr_info->binfo.addr = addr;
1947 	addr_info->binfo.platform_data = addr_info;
1948 	addr_info->debug = debug;
1949 	addr_info->slave_addr = slave_addr;
1950 	addr_info->addr_src = addr_src;
1951 	addr_info->dev = dev;
1952 
1953 	if (dev)
1954 		dev_set_drvdata(dev, addr_info);
1955 
1956 	list_add_tail(&addr_info->link, &ssif_infos);
1957 
1958 	/* Address list will get it */
1959 
1960 out_unlock:
1961 	mutex_unlock(&ssif_infos_mutex);
1962 	return rv;
1963 }
1964 
1965 static void free_ssif_clients(void)
1966 {
1967 	struct ssif_addr_info *info, *tmp;
1968 
1969 	mutex_lock(&ssif_infos_mutex);
1970 	list_for_each_entry_safe(info, tmp, &ssif_infos, link) {
1971 		list_del(&info->link);
1972 		kfree(info->adapter_name);
1973 		kfree(info);
1974 	}
1975 	mutex_unlock(&ssif_infos_mutex);
1976 }
1977 
1978 static unsigned short *ssif_address_list(void)
1979 {
1980 	struct ssif_addr_info *info;
1981 	unsigned int count = 0, i = 0;
1982 	unsigned short *address_list;
1983 
1984 	list_for_each_entry(info, &ssif_infos, link)
1985 		count++;
1986 
1987 	address_list = kcalloc(count + 1, sizeof(*address_list),
1988 			       GFP_KERNEL);
1989 	if (!address_list)
1990 		return NULL;
1991 
1992 	list_for_each_entry(info, &ssif_infos, link) {
1993 		unsigned short addr = info->binfo.addr;
1994 		int j;
1995 
1996 		for (j = 0; j < i; j++) {
1997 			if (address_list[j] == addr)
1998 				/* Found a dup. */
1999 				break;
2000 		}
2001 		if (j == i) /* Didn't find it in the list. */
2002 			address_list[i++] = addr;
2003 	}
2004 	address_list[i] = I2C_CLIENT_END;
2005 
2006 	return address_list;
2007 }
2008 
2009 #ifdef CONFIG_ACPI
2010 static const struct acpi_device_id ssif_acpi_match[] = {
2011 	{ "IPI0001", 0 },
2012 	{ },
2013 };
2014 MODULE_DEVICE_TABLE(acpi, ssif_acpi_match);
2015 #endif
2016 
2017 #ifdef CONFIG_DMI
2018 static int dmi_ipmi_probe(struct platform_device *pdev)
2019 {
2020 	u8 slave_addr = 0;
2021 	u16 i2c_addr;
2022 	int rv;
2023 
2024 	if (!ssif_trydmi)
2025 		return -ENODEV;
2026 
2027 	rv = device_property_read_u16(&pdev->dev, "i2c-addr", &i2c_addr);
2028 	if (rv) {
2029 		dev_warn(&pdev->dev, "No i2c-addr property\n");
2030 		return -ENODEV;
2031 	}
2032 
2033 	rv = device_property_read_u8(&pdev->dev, "slave-addr", &slave_addr);
2034 	if (rv)
2035 		slave_addr = 0x20;
2036 
2037 	return new_ssif_client(i2c_addr, NULL, 0,
2038 			       slave_addr, SI_SMBIOS, &pdev->dev);
2039 }
2040 #else
2041 static int dmi_ipmi_probe(struct platform_device *pdev)
2042 {
2043 	return -ENODEV;
2044 }
2045 #endif
2046 
2047 static const struct i2c_device_id ssif_id[] = {
2048 	{ DEVICE_NAME, 0 },
2049 	{ }
2050 };
2051 MODULE_DEVICE_TABLE(i2c, ssif_id);
2052 
2053 static struct i2c_driver ssif_i2c_driver = {
2054 	.class		= I2C_CLASS_HWMON,
2055 	.driver		= {
2056 		.name			= DEVICE_NAME
2057 	},
2058 	.probe_new	= ssif_probe,
2059 	.remove		= ssif_remove,
2060 	.alert		= ssif_alert,
2061 	.id_table	= ssif_id,
2062 	.detect		= ssif_detect
2063 };
2064 
2065 static int ssif_platform_probe(struct platform_device *dev)
2066 {
2067 	return dmi_ipmi_probe(dev);
2068 }
2069 
2070 static int ssif_platform_remove(struct platform_device *dev)
2071 {
2072 	struct ssif_addr_info *addr_info = dev_get_drvdata(&dev->dev);
2073 
2074 	if (!addr_info)
2075 		return 0;
2076 
2077 	mutex_lock(&ssif_infos_mutex);
2078 	list_del(&addr_info->link);
2079 	kfree(addr_info);
2080 	mutex_unlock(&ssif_infos_mutex);
2081 	return 0;
2082 }
2083 
2084 static const struct platform_device_id ssif_plat_ids[] = {
2085     { "dmi-ipmi-ssif", 0 },
2086     { }
2087 };
2088 
2089 static struct platform_driver ipmi_driver = {
2090 	.driver = {
2091 		.name = DEVICE_NAME,
2092 	},
2093 	.probe		= ssif_platform_probe,
2094 	.remove		= ssif_platform_remove,
2095 	.id_table       = ssif_plat_ids
2096 };
2097 
2098 static int __init init_ipmi_ssif(void)
2099 {
2100 	int i;
2101 	int rv;
2102 
2103 	if (initialized)
2104 		return 0;
2105 
2106 	pr_info("IPMI SSIF Interface driver\n");
2107 
2108 	/* build list for i2c from addr list */
2109 	for (i = 0; i < num_addrs; i++) {
2110 		rv = new_ssif_client(addr[i], adapter_name[i],
2111 				     dbg[i], slave_addrs[i],
2112 				     SI_HARDCODED, NULL);
2113 		if (rv)
2114 			pr_err("Couldn't add hardcoded device at addr 0x%x\n",
2115 			       addr[i]);
2116 	}
2117 
2118 	if (ssif_tryacpi)
2119 		ssif_i2c_driver.driver.acpi_match_table	=
2120 			ACPI_PTR(ssif_acpi_match);
2121 
2122 	if (ssif_trydmi) {
2123 		rv = platform_driver_register(&ipmi_driver);
2124 		if (rv)
2125 			pr_err("Unable to register driver: %d\n", rv);
2126 		else
2127 			platform_registered = true;
2128 	}
2129 
2130 	ssif_i2c_driver.address_list = ssif_address_list();
2131 
2132 	rv = i2c_add_driver(&ssif_i2c_driver);
2133 	if (!rv)
2134 		initialized = true;
2135 
2136 	return rv;
2137 }
2138 module_init(init_ipmi_ssif);
2139 
2140 static void __exit cleanup_ipmi_ssif(void)
2141 {
2142 	if (!initialized)
2143 		return;
2144 
2145 	initialized = false;
2146 
2147 	i2c_del_driver(&ssif_i2c_driver);
2148 
2149 	kfree(ssif_i2c_driver.address_list);
2150 
2151 	if (ssif_trydmi && platform_registered)
2152 		platform_driver_unregister(&ipmi_driver);
2153 
2154 	free_ssif_clients();
2155 }
2156 module_exit(cleanup_ipmi_ssif);
2157 
2158 MODULE_ALIAS("platform:dmi-ipmi-ssif");
2159 MODULE_AUTHOR("Todd C Davis <todd.c.davis@intel.com>, Corey Minyard <minyard@acm.org>");
2160 MODULE_DESCRIPTION("IPMI driver for management controllers on a SMBus");
2161 MODULE_LICENSE("GPL");
2162