xref: /openbmc/linux/drivers/char/ipmi/ipmi_ssif.c (revision 68198dca)
1 /*
2  * ipmi_ssif.c
3  *
4  * The interface to the IPMI driver for SMBus access to a SMBus
5  * compliant device.  Called SSIF by the IPMI spec.
6  *
7  * Author: Intel Corporation
8  *         Todd Davis <todd.c.davis@intel.com>
9  *
10  * Rewritten by Corey Minyard <minyard@acm.org> to support the
11  * non-blocking I2C interface, add support for multi-part
12  * transactions, add PEC support, and general clenaup.
13  *
14  * Copyright 2003 Intel Corporation
15  * Copyright 2005 MontaVista Software
16  *
17  *  This program is free software; you can redistribute it and/or modify it
18  *  under the terms of the GNU General Public License as published by the
19  *  Free Software Foundation; either version 2 of the License, or (at your
20  *  option) any later version.
21  */
22 
23 /*
24  * This file holds the "policy" for the interface to the SSIF state
25  * machine.  It does the configuration, handles timers and interrupts,
26  * and drives the real SSIF state machine.
27  */
28 
29 /*
30  * TODO: Figure out how to use SMB alerts.  This will require a new
31  * interface into the I2C driver, I believe.
32  */
33 
34 #if defined(MODVERSIONS)
35 #include <linux/modversions.h>
36 #endif
37 
38 #include <linux/module.h>
39 #include <linux/moduleparam.h>
40 #include <linux/sched.h>
41 #include <linux/seq_file.h>
42 #include <linux/timer.h>
43 #include <linux/delay.h>
44 #include <linux/errno.h>
45 #include <linux/spinlock.h>
46 #include <linux/slab.h>
47 #include <linux/list.h>
48 #include <linux/i2c.h>
49 #include <linux/ipmi_smi.h>
50 #include <linux/init.h>
51 #include <linux/dmi.h>
52 #include <linux/kthread.h>
53 #include <linux/acpi.h>
54 #include <linux/ctype.h>
55 #include <linux/time64.h>
56 #include "ipmi_si_sm.h"
57 #include "ipmi_dmi.h"
58 
59 #define PFX "ipmi_ssif: "
60 #define DEVICE_NAME "ipmi_ssif"
61 
62 #define IPMI_GET_SYSTEM_INTERFACE_CAPABILITIES_CMD	0x57
63 
64 #define	SSIF_IPMI_REQUEST			2
65 #define	SSIF_IPMI_MULTI_PART_REQUEST_START	6
66 #define	SSIF_IPMI_MULTI_PART_REQUEST_MIDDLE	7
67 #define	SSIF_IPMI_RESPONSE			3
68 #define	SSIF_IPMI_MULTI_PART_RESPONSE_MIDDLE	9
69 
70 /* ssif_debug is a bit-field
71  *	SSIF_DEBUG_MSG -	commands and their responses
72  *	SSIF_DEBUG_STATES -	message states
73  *	SSIF_DEBUG_TIMING -	 Measure times between events in the driver
74  */
75 #define SSIF_DEBUG_TIMING	4
76 #define SSIF_DEBUG_STATE	2
77 #define SSIF_DEBUG_MSG		1
78 #define SSIF_NODEBUG		0
79 #define SSIF_DEFAULT_DEBUG	(SSIF_NODEBUG)
80 
81 /*
82  * Timer values
83  */
84 #define SSIF_MSG_USEC		20000	/* 20ms between message tries. */
85 #define SSIF_MSG_PART_USEC	5000	/* 5ms for a message part */
86 
87 /* How many times to we retry sending/receiving the message. */
88 #define	SSIF_SEND_RETRIES	5
89 #define	SSIF_RECV_RETRIES	250
90 
91 #define SSIF_MSG_MSEC		(SSIF_MSG_USEC / 1000)
92 #define SSIF_MSG_JIFFIES	((SSIF_MSG_USEC * 1000) / TICK_NSEC)
93 #define SSIF_MSG_PART_JIFFIES	((SSIF_MSG_PART_USEC * 1000) / TICK_NSEC)
94 
95 enum ssif_intf_state {
96 	SSIF_NORMAL,
97 	SSIF_GETTING_FLAGS,
98 	SSIF_GETTING_EVENTS,
99 	SSIF_CLEARING_FLAGS,
100 	SSIF_GETTING_MESSAGES,
101 	/* FIXME - add watchdog stuff. */
102 };
103 
104 #define SSIF_IDLE(ssif)	 ((ssif)->ssif_state == SSIF_NORMAL \
105 			  && (ssif)->curr_msg == NULL)
106 
107 /*
108  * Indexes into stats[] in ssif_info below.
109  */
110 enum ssif_stat_indexes {
111 	/* Number of total messages sent. */
112 	SSIF_STAT_sent_messages = 0,
113 
114 	/*
115 	 * Number of message parts sent.  Messages may be broken into
116 	 * parts if they are long.
117 	 */
118 	SSIF_STAT_sent_messages_parts,
119 
120 	/*
121 	 * Number of time a message was retried.
122 	 */
123 	SSIF_STAT_send_retries,
124 
125 	/*
126 	 * Number of times the send of a message failed.
127 	 */
128 	SSIF_STAT_send_errors,
129 
130 	/*
131 	 * Number of message responses received.
132 	 */
133 	SSIF_STAT_received_messages,
134 
135 	/*
136 	 * Number of message fragments received.
137 	 */
138 	SSIF_STAT_received_message_parts,
139 
140 	/*
141 	 * Number of times the receive of a message was retried.
142 	 */
143 	SSIF_STAT_receive_retries,
144 
145 	/*
146 	 * Number of errors receiving messages.
147 	 */
148 	SSIF_STAT_receive_errors,
149 
150 	/*
151 	 * Number of times a flag fetch was requested.
152 	 */
153 	SSIF_STAT_flag_fetches,
154 
155 	/*
156 	 * Number of times the hardware didn't follow the state machine.
157 	 */
158 	SSIF_STAT_hosed,
159 
160 	/*
161 	 * Number of received events.
162 	 */
163 	SSIF_STAT_events,
164 
165 	/* Number of asyncronous messages received. */
166 	SSIF_STAT_incoming_messages,
167 
168 	/* Number of watchdog pretimeouts. */
169 	SSIF_STAT_watchdog_pretimeouts,
170 
171 	/* Number of alers received. */
172 	SSIF_STAT_alerts,
173 
174 	/* Always add statistics before this value, it must be last. */
175 	SSIF_NUM_STATS
176 };
177 
178 struct ssif_addr_info {
179 	struct i2c_board_info binfo;
180 	char *adapter_name;
181 	int debug;
182 	int slave_addr;
183 	enum ipmi_addr_src addr_src;
184 	union ipmi_smi_info_union addr_info;
185 	struct device *dev;
186 	struct i2c_client *client;
187 
188 	struct mutex clients_mutex;
189 	struct list_head clients;
190 
191 	struct list_head link;
192 };
193 
194 struct ssif_info;
195 
196 typedef void (*ssif_i2c_done)(struct ssif_info *ssif_info, int result,
197 			     unsigned char *data, unsigned int len);
198 
199 struct ssif_info {
200 	ipmi_smi_t          intf;
201 	int                 intf_num;
202 	spinlock_t	    lock;
203 	struct ipmi_smi_msg *waiting_msg;
204 	struct ipmi_smi_msg *curr_msg;
205 	enum ssif_intf_state ssif_state;
206 	unsigned long       ssif_debug;
207 
208 	struct ipmi_smi_handlers handlers;
209 
210 	enum ipmi_addr_src addr_source; /* ACPI, PCI, SMBIOS, hardcode, etc. */
211 	union ipmi_smi_info_union addr_info;
212 
213 	/*
214 	 * Flags from the last GET_MSG_FLAGS command, used when an ATTN
215 	 * is set to hold the flags until we are done handling everything
216 	 * from the flags.
217 	 */
218 #define RECEIVE_MSG_AVAIL	0x01
219 #define EVENT_MSG_BUFFER_FULL	0x02
220 #define WDT_PRE_TIMEOUT_INT	0x08
221 	unsigned char       msg_flags;
222 
223 	u8		    global_enables;
224 	bool		    has_event_buffer;
225 	bool		    supports_alert;
226 
227 	/*
228 	 * Used to tell what we should do with alerts.  If we are
229 	 * waiting on a response, read the data immediately.
230 	 */
231 	bool		    got_alert;
232 	bool		    waiting_alert;
233 
234 	/*
235 	 * If set to true, this will request events the next time the
236 	 * state machine is idle.
237 	 */
238 	bool                req_events;
239 
240 	/*
241 	 * If set to true, this will request flags the next time the
242 	 * state machine is idle.
243 	 */
244 	bool                req_flags;
245 
246 	/*
247 	 * Used to perform timer operations when run-to-completion
248 	 * mode is on.  This is a countdown timer.
249 	 */
250 	int                 rtc_us_timer;
251 
252 	/* Used for sending/receiving data.  +1 for the length. */
253 	unsigned char data[IPMI_MAX_MSG_LENGTH + 1];
254 	unsigned int  data_len;
255 
256 	/* Temp receive buffer, gets copied into data. */
257 	unsigned char recv[I2C_SMBUS_BLOCK_MAX];
258 
259 	struct i2c_client *client;
260 	ssif_i2c_done done_handler;
261 
262 	/* Thread interface handling */
263 	struct task_struct *thread;
264 	struct completion wake_thread;
265 	bool stopping;
266 	int i2c_read_write;
267 	int i2c_command;
268 	unsigned char *i2c_data;
269 	unsigned int i2c_size;
270 
271 	struct timer_list retry_timer;
272 	int retries_left;
273 
274 	/* Info from SSIF cmd */
275 	unsigned char max_xmit_msg_size;
276 	unsigned char max_recv_msg_size;
277 	unsigned int  multi_support;
278 	int           supports_pec;
279 
280 #define SSIF_NO_MULTI		0
281 #define SSIF_MULTI_2_PART	1
282 #define SSIF_MULTI_n_PART	2
283 	unsigned char *multi_data;
284 	unsigned int  multi_len;
285 	unsigned int  multi_pos;
286 
287 	atomic_t stats[SSIF_NUM_STATS];
288 };
289 
290 #define ssif_inc_stat(ssif, stat) \
291 	atomic_inc(&(ssif)->stats[SSIF_STAT_ ## stat])
292 #define ssif_get_stat(ssif, stat) \
293 	((unsigned int) atomic_read(&(ssif)->stats[SSIF_STAT_ ## stat]))
294 
295 static bool initialized;
296 
297 static atomic_t next_intf = ATOMIC_INIT(0);
298 
299 static void return_hosed_msg(struct ssif_info *ssif_info,
300 			     struct ipmi_smi_msg *msg);
301 static void start_next_msg(struct ssif_info *ssif_info, unsigned long *flags);
302 static int start_send(struct ssif_info *ssif_info,
303 		      unsigned char   *data,
304 		      unsigned int    len);
305 
306 static unsigned long *ipmi_ssif_lock_cond(struct ssif_info *ssif_info,
307 					  unsigned long *flags)
308 {
309 	spin_lock_irqsave(&ssif_info->lock, *flags);
310 	return flags;
311 }
312 
313 static void ipmi_ssif_unlock_cond(struct ssif_info *ssif_info,
314 				  unsigned long *flags)
315 {
316 	spin_unlock_irqrestore(&ssif_info->lock, *flags);
317 }
318 
319 static void deliver_recv_msg(struct ssif_info *ssif_info,
320 			     struct ipmi_smi_msg *msg)
321 {
322 	ipmi_smi_t    intf = ssif_info->intf;
323 
324 	if (!intf) {
325 		ipmi_free_smi_msg(msg);
326 	} else if (msg->rsp_size < 0) {
327 		return_hosed_msg(ssif_info, msg);
328 		pr_err(PFX
329 		       "Malformed message in deliver_recv_msg: rsp_size = %d\n",
330 		       msg->rsp_size);
331 	} else {
332 		ipmi_smi_msg_received(intf, msg);
333 	}
334 }
335 
336 static void return_hosed_msg(struct ssif_info *ssif_info,
337 			     struct ipmi_smi_msg *msg)
338 {
339 	ssif_inc_stat(ssif_info, hosed);
340 
341 	/* Make it a response */
342 	msg->rsp[0] = msg->data[0] | 4;
343 	msg->rsp[1] = msg->data[1];
344 	msg->rsp[2] = 0xFF; /* Unknown error. */
345 	msg->rsp_size = 3;
346 
347 	deliver_recv_msg(ssif_info, msg);
348 }
349 
350 /*
351  * Must be called with the message lock held.  This will release the
352  * message lock.  Note that the caller will check SSIF_IDLE and start a
353  * new operation, so there is no need to check for new messages to
354  * start in here.
355  */
356 static void start_clear_flags(struct ssif_info *ssif_info, unsigned long *flags)
357 {
358 	unsigned char msg[3];
359 
360 	ssif_info->msg_flags &= ~WDT_PRE_TIMEOUT_INT;
361 	ssif_info->ssif_state = SSIF_CLEARING_FLAGS;
362 	ipmi_ssif_unlock_cond(ssif_info, flags);
363 
364 	/* Make sure the watchdog pre-timeout flag is not set at startup. */
365 	msg[0] = (IPMI_NETFN_APP_REQUEST << 2);
366 	msg[1] = IPMI_CLEAR_MSG_FLAGS_CMD;
367 	msg[2] = WDT_PRE_TIMEOUT_INT;
368 
369 	if (start_send(ssif_info, msg, 3) != 0) {
370 		/* Error, just go to normal state. */
371 		ssif_info->ssif_state = SSIF_NORMAL;
372 	}
373 }
374 
375 static void start_flag_fetch(struct ssif_info *ssif_info, unsigned long *flags)
376 {
377 	unsigned char mb[2];
378 
379 	ssif_info->req_flags = false;
380 	ssif_info->ssif_state = SSIF_GETTING_FLAGS;
381 	ipmi_ssif_unlock_cond(ssif_info, flags);
382 
383 	mb[0] = (IPMI_NETFN_APP_REQUEST << 2);
384 	mb[1] = IPMI_GET_MSG_FLAGS_CMD;
385 	if (start_send(ssif_info, mb, 2) != 0)
386 		ssif_info->ssif_state = SSIF_NORMAL;
387 }
388 
389 static void check_start_send(struct ssif_info *ssif_info, unsigned long *flags,
390 			     struct ipmi_smi_msg *msg)
391 {
392 	if (start_send(ssif_info, msg->data, msg->data_size) != 0) {
393 		unsigned long oflags;
394 
395 		flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
396 		ssif_info->curr_msg = NULL;
397 		ssif_info->ssif_state = SSIF_NORMAL;
398 		ipmi_ssif_unlock_cond(ssif_info, flags);
399 		ipmi_free_smi_msg(msg);
400 	}
401 }
402 
403 static void start_event_fetch(struct ssif_info *ssif_info, unsigned long *flags)
404 {
405 	struct ipmi_smi_msg *msg;
406 
407 	ssif_info->req_events = false;
408 
409 	msg = ipmi_alloc_smi_msg();
410 	if (!msg) {
411 		ssif_info->ssif_state = SSIF_NORMAL;
412 		ipmi_ssif_unlock_cond(ssif_info, flags);
413 		return;
414 	}
415 
416 	ssif_info->curr_msg = msg;
417 	ssif_info->ssif_state = SSIF_GETTING_EVENTS;
418 	ipmi_ssif_unlock_cond(ssif_info, flags);
419 
420 	msg->data[0] = (IPMI_NETFN_APP_REQUEST << 2);
421 	msg->data[1] = IPMI_READ_EVENT_MSG_BUFFER_CMD;
422 	msg->data_size = 2;
423 
424 	check_start_send(ssif_info, flags, msg);
425 }
426 
427 static void start_recv_msg_fetch(struct ssif_info *ssif_info,
428 				 unsigned long *flags)
429 {
430 	struct ipmi_smi_msg *msg;
431 
432 	msg = ipmi_alloc_smi_msg();
433 	if (!msg) {
434 		ssif_info->ssif_state = SSIF_NORMAL;
435 		ipmi_ssif_unlock_cond(ssif_info, flags);
436 		return;
437 	}
438 
439 	ssif_info->curr_msg = msg;
440 	ssif_info->ssif_state = SSIF_GETTING_MESSAGES;
441 	ipmi_ssif_unlock_cond(ssif_info, flags);
442 
443 	msg->data[0] = (IPMI_NETFN_APP_REQUEST << 2);
444 	msg->data[1] = IPMI_GET_MSG_CMD;
445 	msg->data_size = 2;
446 
447 	check_start_send(ssif_info, flags, msg);
448 }
449 
450 /*
451  * Must be called with the message lock held.  This will release the
452  * message lock.  Note that the caller will check SSIF_IDLE and start a
453  * new operation, so there is no need to check for new messages to
454  * start in here.
455  */
456 static void handle_flags(struct ssif_info *ssif_info, unsigned long *flags)
457 {
458 	if (ssif_info->msg_flags & WDT_PRE_TIMEOUT_INT) {
459 		ipmi_smi_t intf = ssif_info->intf;
460 		/* Watchdog pre-timeout */
461 		ssif_inc_stat(ssif_info, watchdog_pretimeouts);
462 		start_clear_flags(ssif_info, flags);
463 		if (intf)
464 			ipmi_smi_watchdog_pretimeout(intf);
465 	} else if (ssif_info->msg_flags & RECEIVE_MSG_AVAIL)
466 		/* Messages available. */
467 		start_recv_msg_fetch(ssif_info, flags);
468 	else if (ssif_info->msg_flags & EVENT_MSG_BUFFER_FULL)
469 		/* Events available. */
470 		start_event_fetch(ssif_info, flags);
471 	else {
472 		ssif_info->ssif_state = SSIF_NORMAL;
473 		ipmi_ssif_unlock_cond(ssif_info, flags);
474 	}
475 }
476 
477 static int ipmi_ssif_thread(void *data)
478 {
479 	struct ssif_info *ssif_info = data;
480 
481 	while (!kthread_should_stop()) {
482 		int result;
483 
484 		/* Wait for something to do */
485 		result = wait_for_completion_interruptible(
486 						&ssif_info->wake_thread);
487 		if (ssif_info->stopping)
488 			break;
489 		if (result == -ERESTARTSYS)
490 			continue;
491 		init_completion(&ssif_info->wake_thread);
492 
493 		if (ssif_info->i2c_read_write == I2C_SMBUS_WRITE) {
494 			result = i2c_smbus_write_block_data(
495 				ssif_info->client, ssif_info->i2c_command,
496 				ssif_info->i2c_data[0],
497 				ssif_info->i2c_data + 1);
498 			ssif_info->done_handler(ssif_info, result, NULL, 0);
499 		} else {
500 			result = i2c_smbus_read_block_data(
501 				ssif_info->client, ssif_info->i2c_command,
502 				ssif_info->i2c_data);
503 			if (result < 0)
504 				ssif_info->done_handler(ssif_info, result,
505 							NULL, 0);
506 			else
507 				ssif_info->done_handler(ssif_info, 0,
508 							ssif_info->i2c_data,
509 							result);
510 		}
511 	}
512 
513 	return 0;
514 }
515 
516 static int ssif_i2c_send(struct ssif_info *ssif_info,
517 			ssif_i2c_done handler,
518 			int read_write, int command,
519 			unsigned char *data, unsigned int size)
520 {
521 	ssif_info->done_handler = handler;
522 
523 	ssif_info->i2c_read_write = read_write;
524 	ssif_info->i2c_command = command;
525 	ssif_info->i2c_data = data;
526 	ssif_info->i2c_size = size;
527 	complete(&ssif_info->wake_thread);
528 	return 0;
529 }
530 
531 
532 static void msg_done_handler(struct ssif_info *ssif_info, int result,
533 			     unsigned char *data, unsigned int len);
534 
535 static void start_get(struct ssif_info *ssif_info)
536 {
537 	int rv;
538 
539 	ssif_info->rtc_us_timer = 0;
540 	ssif_info->multi_pos = 0;
541 
542 	rv = ssif_i2c_send(ssif_info, msg_done_handler, I2C_SMBUS_READ,
543 			  SSIF_IPMI_RESPONSE,
544 			  ssif_info->recv, I2C_SMBUS_BLOCK_DATA);
545 	if (rv < 0) {
546 		/* request failed, just return the error. */
547 		if (ssif_info->ssif_debug & SSIF_DEBUG_MSG)
548 			pr_info("Error from i2c_non_blocking_op(5)\n");
549 
550 		msg_done_handler(ssif_info, -EIO, NULL, 0);
551 	}
552 }
553 
554 static void retry_timeout(struct timer_list *t)
555 {
556 	struct ssif_info *ssif_info = from_timer(ssif_info, t, retry_timer);
557 	unsigned long oflags, *flags;
558 	bool waiting;
559 
560 	if (ssif_info->stopping)
561 		return;
562 
563 	flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
564 	waiting = ssif_info->waiting_alert;
565 	ssif_info->waiting_alert = false;
566 	ipmi_ssif_unlock_cond(ssif_info, flags);
567 
568 	if (waiting)
569 		start_get(ssif_info);
570 }
571 
572 
573 static void ssif_alert(struct i2c_client *client, enum i2c_alert_protocol type,
574 		       unsigned int data)
575 {
576 	struct ssif_info *ssif_info = i2c_get_clientdata(client);
577 	unsigned long oflags, *flags;
578 	bool do_get = false;
579 
580 	if (type != I2C_PROTOCOL_SMBUS_ALERT)
581 		return;
582 
583 	ssif_inc_stat(ssif_info, alerts);
584 
585 	flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
586 	if (ssif_info->waiting_alert) {
587 		ssif_info->waiting_alert = false;
588 		del_timer(&ssif_info->retry_timer);
589 		do_get = true;
590 	} else if (ssif_info->curr_msg) {
591 		ssif_info->got_alert = true;
592 	}
593 	ipmi_ssif_unlock_cond(ssif_info, flags);
594 	if (do_get)
595 		start_get(ssif_info);
596 }
597 
598 static int start_resend(struct ssif_info *ssif_info);
599 
600 static void msg_done_handler(struct ssif_info *ssif_info, int result,
601 			     unsigned char *data, unsigned int len)
602 {
603 	struct ipmi_smi_msg *msg;
604 	unsigned long oflags, *flags;
605 	int rv;
606 
607 	/*
608 	 * We are single-threaded here, so no need for a lock until we
609 	 * start messing with driver states or the queues.
610 	 */
611 
612 	if (result < 0) {
613 		ssif_info->retries_left--;
614 		if (ssif_info->retries_left > 0) {
615 			ssif_inc_stat(ssif_info, receive_retries);
616 
617 			flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
618 			ssif_info->waiting_alert = true;
619 			ssif_info->rtc_us_timer = SSIF_MSG_USEC;
620 			mod_timer(&ssif_info->retry_timer,
621 				  jiffies + SSIF_MSG_JIFFIES);
622 			ipmi_ssif_unlock_cond(ssif_info, flags);
623 			return;
624 		}
625 
626 		ssif_inc_stat(ssif_info, receive_errors);
627 
628 		if  (ssif_info->ssif_debug & SSIF_DEBUG_MSG)
629 			pr_info("Error in msg_done_handler: %d\n", result);
630 		len = 0;
631 		goto continue_op;
632 	}
633 
634 	if ((len > 1) && (ssif_info->multi_pos == 0)
635 				&& (data[0] == 0x00) && (data[1] == 0x01)) {
636 		/* Start of multi-part read.  Start the next transaction. */
637 		int i;
638 
639 		ssif_inc_stat(ssif_info, received_message_parts);
640 
641 		/* Remove the multi-part read marker. */
642 		len -= 2;
643 		for (i = 0; i < len; i++)
644 			ssif_info->data[i] = data[i+2];
645 		ssif_info->multi_len = len;
646 		ssif_info->multi_pos = 1;
647 
648 		rv = ssif_i2c_send(ssif_info, msg_done_handler, I2C_SMBUS_READ,
649 				  SSIF_IPMI_MULTI_PART_RESPONSE_MIDDLE,
650 				  ssif_info->recv, I2C_SMBUS_BLOCK_DATA);
651 		if (rv < 0) {
652 			if (ssif_info->ssif_debug & SSIF_DEBUG_MSG)
653 				pr_info("Error from i2c_non_blocking_op(1)\n");
654 
655 			result = -EIO;
656 		} else
657 			return;
658 	} else if (ssif_info->multi_pos) {
659 		/* Middle of multi-part read.  Start the next transaction. */
660 		int i;
661 		unsigned char blocknum;
662 
663 		if (len == 0) {
664 			result = -EIO;
665 			if (ssif_info->ssif_debug & SSIF_DEBUG_MSG)
666 				pr_info(PFX "Middle message with no data\n");
667 
668 			goto continue_op;
669 		}
670 
671 		blocknum = data[0];
672 
673 		if (ssif_info->multi_len + len - 1 > IPMI_MAX_MSG_LENGTH) {
674 			/* Received message too big, abort the operation. */
675 			result = -E2BIG;
676 			if (ssif_info->ssif_debug & SSIF_DEBUG_MSG)
677 				pr_info("Received message too big\n");
678 
679 			goto continue_op;
680 		}
681 
682 		/* Remove the blocknum from the data. */
683 		len--;
684 		for (i = 0; i < len; i++)
685 			ssif_info->data[i + ssif_info->multi_len] = data[i + 1];
686 		ssif_info->multi_len += len;
687 		if (blocknum == 0xff) {
688 			/* End of read */
689 			len = ssif_info->multi_len;
690 			data = ssif_info->data;
691 		} else if (blocknum + 1 != ssif_info->multi_pos) {
692 			/*
693 			 * Out of sequence block, just abort.  Block
694 			 * numbers start at zero for the second block,
695 			 * but multi_pos starts at one, so the +1.
696 			 */
697 			result = -EIO;
698 		} else {
699 			ssif_inc_stat(ssif_info, received_message_parts);
700 
701 			ssif_info->multi_pos++;
702 
703 			rv = ssif_i2c_send(ssif_info, msg_done_handler,
704 					   I2C_SMBUS_READ,
705 					   SSIF_IPMI_MULTI_PART_RESPONSE_MIDDLE,
706 					   ssif_info->recv,
707 					   I2C_SMBUS_BLOCK_DATA);
708 			if (rv < 0) {
709 				if (ssif_info->ssif_debug & SSIF_DEBUG_MSG)
710 					pr_info(PFX
711 						"Error from ssif_i2c_send\n");
712 
713 				result = -EIO;
714 			} else
715 				return;
716 		}
717 	}
718 
719 	if (result < 0) {
720 		ssif_inc_stat(ssif_info, receive_errors);
721 	} else {
722 		ssif_inc_stat(ssif_info, received_messages);
723 		ssif_inc_stat(ssif_info, received_message_parts);
724 	}
725 
726 
727  continue_op:
728 	if (ssif_info->ssif_debug & SSIF_DEBUG_STATE)
729 		pr_info(PFX "DONE 1: state = %d, result=%d.\n",
730 			ssif_info->ssif_state, result);
731 
732 	flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
733 	msg = ssif_info->curr_msg;
734 	if (msg) {
735 		msg->rsp_size = len;
736 		if (msg->rsp_size > IPMI_MAX_MSG_LENGTH)
737 			msg->rsp_size = IPMI_MAX_MSG_LENGTH;
738 		memcpy(msg->rsp, data, msg->rsp_size);
739 		ssif_info->curr_msg = NULL;
740 	}
741 
742 	switch (ssif_info->ssif_state) {
743 	case SSIF_NORMAL:
744 		ipmi_ssif_unlock_cond(ssif_info, flags);
745 		if (!msg)
746 			break;
747 
748 		if (result < 0)
749 			return_hosed_msg(ssif_info, msg);
750 		else
751 			deliver_recv_msg(ssif_info, msg);
752 		break;
753 
754 	case SSIF_GETTING_FLAGS:
755 		/* We got the flags from the SSIF, now handle them. */
756 		if ((result < 0) || (len < 4) || (data[2] != 0)) {
757 			/*
758 			 * Error fetching flags, or invalid length,
759 			 * just give up for now.
760 			 */
761 			ssif_info->ssif_state = SSIF_NORMAL;
762 			ipmi_ssif_unlock_cond(ssif_info, flags);
763 			pr_warn(PFX "Error getting flags: %d %d, %x\n",
764 			       result, len, data[2]);
765 		} else if (data[0] != (IPMI_NETFN_APP_REQUEST | 1) << 2
766 			   || data[1] != IPMI_GET_MSG_FLAGS_CMD) {
767 			/*
768 			 * Don't abort here, maybe it was a queued
769 			 * response to a previous command.
770 			 */
771 			ipmi_ssif_unlock_cond(ssif_info, flags);
772 			pr_warn(PFX "Invalid response getting flags: %x %x\n",
773 				data[0], data[1]);
774 		} else {
775 			ssif_inc_stat(ssif_info, flag_fetches);
776 			ssif_info->msg_flags = data[3];
777 			handle_flags(ssif_info, flags);
778 		}
779 		break;
780 
781 	case SSIF_CLEARING_FLAGS:
782 		/* We cleared the flags. */
783 		if ((result < 0) || (len < 3) || (data[2] != 0)) {
784 			/* Error clearing flags */
785 			pr_warn(PFX "Error clearing flags: %d %d, %x\n",
786 			       result, len, data[2]);
787 		} else if (data[0] != (IPMI_NETFN_APP_REQUEST | 1) << 2
788 			   || data[1] != IPMI_CLEAR_MSG_FLAGS_CMD) {
789 			pr_warn(PFX "Invalid response clearing flags: %x %x\n",
790 				data[0], data[1]);
791 		}
792 		ssif_info->ssif_state = SSIF_NORMAL;
793 		ipmi_ssif_unlock_cond(ssif_info, flags);
794 		break;
795 
796 	case SSIF_GETTING_EVENTS:
797 		if ((result < 0) || (len < 3) || (msg->rsp[2] != 0)) {
798 			/* Error getting event, probably done. */
799 			msg->done(msg);
800 
801 			/* Take off the event flag. */
802 			ssif_info->msg_flags &= ~EVENT_MSG_BUFFER_FULL;
803 			handle_flags(ssif_info, flags);
804 		} else if (msg->rsp[0] != (IPMI_NETFN_APP_REQUEST | 1) << 2
805 			   || msg->rsp[1] != IPMI_READ_EVENT_MSG_BUFFER_CMD) {
806 			pr_warn(PFX "Invalid response getting events: %x %x\n",
807 				msg->rsp[0], msg->rsp[1]);
808 			msg->done(msg);
809 			/* Take off the event flag. */
810 			ssif_info->msg_flags &= ~EVENT_MSG_BUFFER_FULL;
811 			handle_flags(ssif_info, flags);
812 		} else {
813 			handle_flags(ssif_info, flags);
814 			ssif_inc_stat(ssif_info, events);
815 			deliver_recv_msg(ssif_info, msg);
816 		}
817 		break;
818 
819 	case SSIF_GETTING_MESSAGES:
820 		if ((result < 0) || (len < 3) || (msg->rsp[2] != 0)) {
821 			/* Error getting event, probably done. */
822 			msg->done(msg);
823 
824 			/* Take off the msg flag. */
825 			ssif_info->msg_flags &= ~RECEIVE_MSG_AVAIL;
826 			handle_flags(ssif_info, flags);
827 		} else if (msg->rsp[0] != (IPMI_NETFN_APP_REQUEST | 1) << 2
828 			   || msg->rsp[1] != IPMI_GET_MSG_CMD) {
829 			pr_warn(PFX "Invalid response clearing flags: %x %x\n",
830 				msg->rsp[0], msg->rsp[1]);
831 			msg->done(msg);
832 
833 			/* Take off the msg flag. */
834 			ssif_info->msg_flags &= ~RECEIVE_MSG_AVAIL;
835 			handle_flags(ssif_info, flags);
836 		} else {
837 			ssif_inc_stat(ssif_info, incoming_messages);
838 			handle_flags(ssif_info, flags);
839 			deliver_recv_msg(ssif_info, msg);
840 		}
841 		break;
842 	}
843 
844 	flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
845 	if (SSIF_IDLE(ssif_info) && !ssif_info->stopping) {
846 		if (ssif_info->req_events)
847 			start_event_fetch(ssif_info, flags);
848 		else if (ssif_info->req_flags)
849 			start_flag_fetch(ssif_info, flags);
850 		else
851 			start_next_msg(ssif_info, flags);
852 	} else
853 		ipmi_ssif_unlock_cond(ssif_info, flags);
854 
855 	if (ssif_info->ssif_debug & SSIF_DEBUG_STATE)
856 		pr_info(PFX "DONE 2: state = %d.\n", ssif_info->ssif_state);
857 }
858 
859 static void msg_written_handler(struct ssif_info *ssif_info, int result,
860 				unsigned char *data, unsigned int len)
861 {
862 	int rv;
863 
864 	/* We are single-threaded here, so no need for a lock. */
865 	if (result < 0) {
866 		ssif_info->retries_left--;
867 		if (ssif_info->retries_left > 0) {
868 			if (!start_resend(ssif_info)) {
869 				ssif_inc_stat(ssif_info, send_retries);
870 				return;
871 			}
872 			/* request failed, just return the error. */
873 			ssif_inc_stat(ssif_info, send_errors);
874 
875 			if (ssif_info->ssif_debug & SSIF_DEBUG_MSG)
876 				pr_info(PFX
877 					"Out of retries in msg_written_handler\n");
878 			msg_done_handler(ssif_info, -EIO, NULL, 0);
879 			return;
880 		}
881 
882 		ssif_inc_stat(ssif_info, send_errors);
883 
884 		/*
885 		 * Got an error on transmit, let the done routine
886 		 * handle it.
887 		 */
888 		if (ssif_info->ssif_debug & SSIF_DEBUG_MSG)
889 			pr_info("Error in msg_written_handler: %d\n", result);
890 
891 		msg_done_handler(ssif_info, result, NULL, 0);
892 		return;
893 	}
894 
895 	if (ssif_info->multi_data) {
896 		/*
897 		 * In the middle of a multi-data write.  See the comment
898 		 * in the SSIF_MULTI_n_PART case in the probe function
899 		 * for details on the intricacies of this.
900 		 */
901 		int left;
902 		unsigned char *data_to_send;
903 
904 		ssif_inc_stat(ssif_info, sent_messages_parts);
905 
906 		left = ssif_info->multi_len - ssif_info->multi_pos;
907 		if (left > 32)
908 			left = 32;
909 		/* Length byte. */
910 		ssif_info->multi_data[ssif_info->multi_pos] = left;
911 		data_to_send = ssif_info->multi_data + ssif_info->multi_pos;
912 		ssif_info->multi_pos += left;
913 		if (left < 32)
914 			/*
915 			 * Write is finished.  Note that we must end
916 			 * with a write of less than 32 bytes to
917 			 * complete the transaction, even if it is
918 			 * zero bytes.
919 			 */
920 			ssif_info->multi_data = NULL;
921 
922 		rv = ssif_i2c_send(ssif_info, msg_written_handler,
923 				  I2C_SMBUS_WRITE,
924 				  SSIF_IPMI_MULTI_PART_REQUEST_MIDDLE,
925 				  data_to_send,
926 				  I2C_SMBUS_BLOCK_DATA);
927 		if (rv < 0) {
928 			/* request failed, just return the error. */
929 			ssif_inc_stat(ssif_info, send_errors);
930 
931 			if (ssif_info->ssif_debug & SSIF_DEBUG_MSG)
932 				pr_info("Error from i2c_non_blocking_op(3)\n");
933 			msg_done_handler(ssif_info, -EIO, NULL, 0);
934 		}
935 	} else {
936 		/* Ready to request the result. */
937 		unsigned long oflags, *flags;
938 
939 		ssif_inc_stat(ssif_info, sent_messages);
940 		ssif_inc_stat(ssif_info, sent_messages_parts);
941 
942 		flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
943 		if (ssif_info->got_alert) {
944 			/* The result is already ready, just start it. */
945 			ssif_info->got_alert = false;
946 			ipmi_ssif_unlock_cond(ssif_info, flags);
947 			start_get(ssif_info);
948 		} else {
949 			/* Wait a jiffie then request the next message */
950 			ssif_info->waiting_alert = true;
951 			ssif_info->retries_left = SSIF_RECV_RETRIES;
952 			ssif_info->rtc_us_timer = SSIF_MSG_PART_USEC;
953 			mod_timer(&ssif_info->retry_timer,
954 				  jiffies + SSIF_MSG_PART_JIFFIES);
955 			ipmi_ssif_unlock_cond(ssif_info, flags);
956 		}
957 	}
958 }
959 
960 static int start_resend(struct ssif_info *ssif_info)
961 {
962 	int rv;
963 	int command;
964 
965 	ssif_info->got_alert = false;
966 
967 	if (ssif_info->data_len > 32) {
968 		command = SSIF_IPMI_MULTI_PART_REQUEST_START;
969 		ssif_info->multi_data = ssif_info->data;
970 		ssif_info->multi_len = ssif_info->data_len;
971 		/*
972 		 * Subtle thing, this is 32, not 33, because we will
973 		 * overwrite the thing at position 32 (which was just
974 		 * transmitted) with the new length.
975 		 */
976 		ssif_info->multi_pos = 32;
977 		ssif_info->data[0] = 32;
978 	} else {
979 		ssif_info->multi_data = NULL;
980 		command = SSIF_IPMI_REQUEST;
981 		ssif_info->data[0] = ssif_info->data_len;
982 	}
983 
984 	rv = ssif_i2c_send(ssif_info, msg_written_handler, I2C_SMBUS_WRITE,
985 			  command, ssif_info->data, I2C_SMBUS_BLOCK_DATA);
986 	if (rv && (ssif_info->ssif_debug & SSIF_DEBUG_MSG))
987 		pr_info("Error from i2c_non_blocking_op(4)\n");
988 	return rv;
989 }
990 
991 static int start_send(struct ssif_info *ssif_info,
992 		      unsigned char   *data,
993 		      unsigned int    len)
994 {
995 	if (len > IPMI_MAX_MSG_LENGTH)
996 		return -E2BIG;
997 	if (len > ssif_info->max_xmit_msg_size)
998 		return -E2BIG;
999 
1000 	ssif_info->retries_left = SSIF_SEND_RETRIES;
1001 	memcpy(ssif_info->data + 1, data, len);
1002 	ssif_info->data_len = len;
1003 	return start_resend(ssif_info);
1004 }
1005 
1006 /* Must be called with the message lock held. */
1007 static void start_next_msg(struct ssif_info *ssif_info, unsigned long *flags)
1008 {
1009 	struct ipmi_smi_msg *msg;
1010 	unsigned long oflags;
1011 
1012  restart:
1013 	if (!SSIF_IDLE(ssif_info)) {
1014 		ipmi_ssif_unlock_cond(ssif_info, flags);
1015 		return;
1016 	}
1017 
1018 	if (!ssif_info->waiting_msg) {
1019 		ssif_info->curr_msg = NULL;
1020 		ipmi_ssif_unlock_cond(ssif_info, flags);
1021 	} else {
1022 		int rv;
1023 
1024 		ssif_info->curr_msg = ssif_info->waiting_msg;
1025 		ssif_info->waiting_msg = NULL;
1026 		ipmi_ssif_unlock_cond(ssif_info, flags);
1027 		rv = start_send(ssif_info,
1028 				ssif_info->curr_msg->data,
1029 				ssif_info->curr_msg->data_size);
1030 		if (rv) {
1031 			msg = ssif_info->curr_msg;
1032 			ssif_info->curr_msg = NULL;
1033 			return_hosed_msg(ssif_info, msg);
1034 			flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
1035 			goto restart;
1036 		}
1037 	}
1038 }
1039 
1040 static void sender(void                *send_info,
1041 		   struct ipmi_smi_msg *msg)
1042 {
1043 	struct ssif_info *ssif_info = (struct ssif_info *) send_info;
1044 	unsigned long oflags, *flags;
1045 
1046 	BUG_ON(ssif_info->waiting_msg);
1047 	ssif_info->waiting_msg = msg;
1048 
1049 	flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
1050 	start_next_msg(ssif_info, flags);
1051 
1052 	if (ssif_info->ssif_debug & SSIF_DEBUG_TIMING) {
1053 		struct timespec64 t;
1054 
1055 		ktime_get_real_ts64(&t);
1056 		pr_info("**Enqueue %02x %02x: %lld.%6.6ld\n",
1057 		       msg->data[0], msg->data[1],
1058 		       (long long) t.tv_sec, (long) t.tv_nsec / NSEC_PER_USEC);
1059 	}
1060 }
1061 
1062 static int get_smi_info(void *send_info, struct ipmi_smi_info *data)
1063 {
1064 	struct ssif_info *ssif_info = send_info;
1065 
1066 	data->addr_src = ssif_info->addr_source;
1067 	data->dev = &ssif_info->client->dev;
1068 	data->addr_info = ssif_info->addr_info;
1069 	get_device(data->dev);
1070 
1071 	return 0;
1072 }
1073 
1074 /*
1075  * Instead of having our own timer to periodically check the message
1076  * flags, we let the message handler drive us.
1077  */
1078 static void request_events(void *send_info)
1079 {
1080 	struct ssif_info *ssif_info = (struct ssif_info *) send_info;
1081 	unsigned long oflags, *flags;
1082 
1083 	if (!ssif_info->has_event_buffer)
1084 		return;
1085 
1086 	flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
1087 	/*
1088 	 * Request flags first, not events, because the lower layer
1089 	 * doesn't have a way to send an attention.  But make sure
1090 	 * event checking still happens.
1091 	 */
1092 	ssif_info->req_events = true;
1093 	if (SSIF_IDLE(ssif_info))
1094 		start_flag_fetch(ssif_info, flags);
1095 	else {
1096 		ssif_info->req_flags = true;
1097 		ipmi_ssif_unlock_cond(ssif_info, flags);
1098 	}
1099 }
1100 
1101 static int inc_usecount(void *send_info)
1102 {
1103 	struct ssif_info *ssif_info = send_info;
1104 
1105 	if (!i2c_get_adapter(i2c_adapter_id(ssif_info->client->adapter)))
1106 		return -ENODEV;
1107 
1108 	i2c_use_client(ssif_info->client);
1109 	return 0;
1110 }
1111 
1112 static void dec_usecount(void *send_info)
1113 {
1114 	struct ssif_info *ssif_info = send_info;
1115 
1116 	i2c_release_client(ssif_info->client);
1117 	i2c_put_adapter(ssif_info->client->adapter);
1118 }
1119 
1120 static int ssif_start_processing(void *send_info,
1121 				 ipmi_smi_t intf)
1122 {
1123 	struct ssif_info *ssif_info = send_info;
1124 
1125 	ssif_info->intf = intf;
1126 
1127 	return 0;
1128 }
1129 
1130 #define MAX_SSIF_BMCS 4
1131 
1132 static unsigned short addr[MAX_SSIF_BMCS];
1133 static int num_addrs;
1134 module_param_array(addr, ushort, &num_addrs, 0);
1135 MODULE_PARM_DESC(addr, "The addresses to scan for IPMI BMCs on the SSIFs.");
1136 
1137 static char *adapter_name[MAX_SSIF_BMCS];
1138 static int num_adapter_names;
1139 module_param_array(adapter_name, charp, &num_adapter_names, 0);
1140 MODULE_PARM_DESC(adapter_name, "The string name of the I2C device that has the BMC.  By default all devices are scanned.");
1141 
1142 static int slave_addrs[MAX_SSIF_BMCS];
1143 static int num_slave_addrs;
1144 module_param_array(slave_addrs, int, &num_slave_addrs, 0);
1145 MODULE_PARM_DESC(slave_addrs,
1146 		 "The default IPMB slave address for the controller.");
1147 
1148 static bool alerts_broken;
1149 module_param(alerts_broken, bool, 0);
1150 MODULE_PARM_DESC(alerts_broken, "Don't enable alerts for the controller.");
1151 
1152 /*
1153  * Bit 0 enables message debugging, bit 1 enables state debugging, and
1154  * bit 2 enables timing debugging.  This is an array indexed by
1155  * interface number"
1156  */
1157 static int dbg[MAX_SSIF_BMCS];
1158 static int num_dbg;
1159 module_param_array(dbg, int, &num_dbg, 0);
1160 MODULE_PARM_DESC(dbg, "Turn on debugging.");
1161 
1162 static bool ssif_dbg_probe;
1163 module_param_named(dbg_probe, ssif_dbg_probe, bool, 0);
1164 MODULE_PARM_DESC(dbg_probe, "Enable debugging of probing of adapters.");
1165 
1166 static bool ssif_tryacpi = true;
1167 module_param_named(tryacpi, ssif_tryacpi, bool, 0);
1168 MODULE_PARM_DESC(tryacpi, "Setting this to zero will disable the default scan of the interfaces identified via ACPI");
1169 
1170 static bool ssif_trydmi = true;
1171 module_param_named(trydmi, ssif_trydmi, bool, 0);
1172 MODULE_PARM_DESC(trydmi, "Setting this to zero will disable the default scan of the interfaces identified via DMI (SMBIOS)");
1173 
1174 static DEFINE_MUTEX(ssif_infos_mutex);
1175 static LIST_HEAD(ssif_infos);
1176 
1177 #define IPMI_SSIF_ATTR(name) \
1178 static ssize_t ipmi_##name##_show(struct device *dev,			\
1179 				  struct device_attribute *attr,	\
1180 				  char *buf)				\
1181 {									\
1182 	struct ssif_info *ssif_info = dev_get_drvdata(dev);		\
1183 									\
1184 	return snprintf(buf, 10, "%u\n", ssif_get_stat(ssif_info, name));\
1185 }									\
1186 static DEVICE_ATTR(name, S_IRUGO, ipmi_##name##_show, NULL)
1187 
1188 static ssize_t ipmi_type_show(struct device *dev,
1189 			      struct device_attribute *attr,
1190 			      char *buf)
1191 {
1192 	return snprintf(buf, 10, "ssif\n");
1193 }
1194 static DEVICE_ATTR(type, S_IRUGO, ipmi_type_show, NULL);
1195 
1196 IPMI_SSIF_ATTR(sent_messages);
1197 IPMI_SSIF_ATTR(sent_messages_parts);
1198 IPMI_SSIF_ATTR(send_retries);
1199 IPMI_SSIF_ATTR(send_errors);
1200 IPMI_SSIF_ATTR(received_messages);
1201 IPMI_SSIF_ATTR(received_message_parts);
1202 IPMI_SSIF_ATTR(receive_retries);
1203 IPMI_SSIF_ATTR(receive_errors);
1204 IPMI_SSIF_ATTR(flag_fetches);
1205 IPMI_SSIF_ATTR(hosed);
1206 IPMI_SSIF_ATTR(events);
1207 IPMI_SSIF_ATTR(watchdog_pretimeouts);
1208 IPMI_SSIF_ATTR(alerts);
1209 
1210 static struct attribute *ipmi_ssif_dev_attrs[] = {
1211 	&dev_attr_type.attr,
1212 	&dev_attr_sent_messages.attr,
1213 	&dev_attr_sent_messages_parts.attr,
1214 	&dev_attr_send_retries.attr,
1215 	&dev_attr_send_errors.attr,
1216 	&dev_attr_received_messages.attr,
1217 	&dev_attr_received_message_parts.attr,
1218 	&dev_attr_receive_retries.attr,
1219 	&dev_attr_receive_errors.attr,
1220 	&dev_attr_flag_fetches.attr,
1221 	&dev_attr_hosed.attr,
1222 	&dev_attr_events.attr,
1223 	&dev_attr_watchdog_pretimeouts.attr,
1224 	&dev_attr_alerts.attr,
1225 	NULL
1226 };
1227 
1228 static const struct attribute_group ipmi_ssif_dev_attr_group = {
1229 	.attrs		= ipmi_ssif_dev_attrs,
1230 };
1231 
1232 static int ssif_remove(struct i2c_client *client)
1233 {
1234 	struct ssif_info *ssif_info = i2c_get_clientdata(client);
1235 	struct ssif_addr_info *addr_info;
1236 	int rv;
1237 
1238 	if (!ssif_info)
1239 		return 0;
1240 
1241 	/*
1242 	 * After this point, we won't deliver anything asychronously
1243 	 * to the message handler.  We can unregister ourself.
1244 	 */
1245 	rv = ipmi_unregister_smi(ssif_info->intf);
1246 	if (rv) {
1247 		pr_err(PFX "Unable to unregister device: errno=%d\n", rv);
1248 		return rv;
1249 	}
1250 	ssif_info->intf = NULL;
1251 
1252 	device_remove_group(&ssif_info->client->dev, &ipmi_ssif_dev_attr_group);
1253 	dev_set_drvdata(&ssif_info->client->dev, NULL);
1254 
1255 	/* make sure the driver is not looking for flags any more. */
1256 	while (ssif_info->ssif_state != SSIF_NORMAL)
1257 		schedule_timeout(1);
1258 
1259 	ssif_info->stopping = true;
1260 	del_timer_sync(&ssif_info->retry_timer);
1261 	if (ssif_info->thread) {
1262 		complete(&ssif_info->wake_thread);
1263 		kthread_stop(ssif_info->thread);
1264 	}
1265 
1266 	list_for_each_entry(addr_info, &ssif_infos, link) {
1267 		if (addr_info->client == client) {
1268 			addr_info->client = NULL;
1269 			break;
1270 		}
1271 	}
1272 
1273 	/*
1274 	 * No message can be outstanding now, we have removed the
1275 	 * upper layer and it permitted us to do so.
1276 	 */
1277 	kfree(ssif_info);
1278 	return 0;
1279 }
1280 
1281 static int do_cmd(struct i2c_client *client, int len, unsigned char *msg,
1282 		  int *resp_len, unsigned char *resp)
1283 {
1284 	int retry_cnt;
1285 	int ret;
1286 
1287 	retry_cnt = SSIF_SEND_RETRIES;
1288  retry1:
1289 	ret = i2c_smbus_write_block_data(client, SSIF_IPMI_REQUEST, len, msg);
1290 	if (ret) {
1291 		retry_cnt--;
1292 		if (retry_cnt > 0)
1293 			goto retry1;
1294 		return -ENODEV;
1295 	}
1296 
1297 	ret = -ENODEV;
1298 	retry_cnt = SSIF_RECV_RETRIES;
1299 	while (retry_cnt > 0) {
1300 		ret = i2c_smbus_read_block_data(client, SSIF_IPMI_RESPONSE,
1301 						resp);
1302 		if (ret > 0)
1303 			break;
1304 		msleep(SSIF_MSG_MSEC);
1305 		retry_cnt--;
1306 		if (retry_cnt <= 0)
1307 			break;
1308 	}
1309 
1310 	if (ret > 0) {
1311 		/* Validate that the response is correct. */
1312 		if (ret < 3 ||
1313 		    (resp[0] != (msg[0] | (1 << 2))) ||
1314 		    (resp[1] != msg[1]))
1315 			ret = -EINVAL;
1316 		else {
1317 			*resp_len = ret;
1318 			ret = 0;
1319 		}
1320 	}
1321 
1322 	return ret;
1323 }
1324 
1325 static int ssif_detect(struct i2c_client *client, struct i2c_board_info *info)
1326 {
1327 	unsigned char *resp;
1328 	unsigned char msg[3];
1329 	int           rv;
1330 	int           len;
1331 
1332 	resp = kmalloc(IPMI_MAX_MSG_LENGTH, GFP_KERNEL);
1333 	if (!resp)
1334 		return -ENOMEM;
1335 
1336 	/* Do a Get Device ID command, since it is required. */
1337 	msg[0] = IPMI_NETFN_APP_REQUEST << 2;
1338 	msg[1] = IPMI_GET_DEVICE_ID_CMD;
1339 	rv = do_cmd(client, 2, msg, &len, resp);
1340 	if (rv)
1341 		rv = -ENODEV;
1342 	else
1343 		strlcpy(info->type, DEVICE_NAME, I2C_NAME_SIZE);
1344 	kfree(resp);
1345 	return rv;
1346 }
1347 
1348 #ifdef CONFIG_IPMI_PROC_INTERFACE
1349 static int smi_type_proc_show(struct seq_file *m, void *v)
1350 {
1351 	seq_puts(m, "ssif\n");
1352 
1353 	return 0;
1354 }
1355 
1356 static int smi_type_proc_open(struct inode *inode, struct file *file)
1357 {
1358 	return single_open(file, smi_type_proc_show, inode->i_private);
1359 }
1360 
1361 static const struct file_operations smi_type_proc_ops = {
1362 	.open		= smi_type_proc_open,
1363 	.read		= seq_read,
1364 	.llseek		= seq_lseek,
1365 	.release	= single_release,
1366 };
1367 
1368 static int smi_stats_proc_show(struct seq_file *m, void *v)
1369 {
1370 	struct ssif_info *ssif_info = m->private;
1371 
1372 	seq_printf(m, "sent_messages:          %u\n",
1373 		   ssif_get_stat(ssif_info, sent_messages));
1374 	seq_printf(m, "sent_messages_parts:    %u\n",
1375 		   ssif_get_stat(ssif_info, sent_messages_parts));
1376 	seq_printf(m, "send_retries:           %u\n",
1377 		   ssif_get_stat(ssif_info, send_retries));
1378 	seq_printf(m, "send_errors:            %u\n",
1379 		   ssif_get_stat(ssif_info, send_errors));
1380 	seq_printf(m, "received_messages:      %u\n",
1381 		   ssif_get_stat(ssif_info, received_messages));
1382 	seq_printf(m, "received_message_parts: %u\n",
1383 		   ssif_get_stat(ssif_info, received_message_parts));
1384 	seq_printf(m, "receive_retries:        %u\n",
1385 		   ssif_get_stat(ssif_info, receive_retries));
1386 	seq_printf(m, "receive_errors:         %u\n",
1387 		   ssif_get_stat(ssif_info, receive_errors));
1388 	seq_printf(m, "flag_fetches:           %u\n",
1389 		   ssif_get_stat(ssif_info, flag_fetches));
1390 	seq_printf(m, "hosed:                  %u\n",
1391 		   ssif_get_stat(ssif_info, hosed));
1392 	seq_printf(m, "events:                 %u\n",
1393 		   ssif_get_stat(ssif_info, events));
1394 	seq_printf(m, "watchdog_pretimeouts:   %u\n",
1395 		   ssif_get_stat(ssif_info, watchdog_pretimeouts));
1396 	seq_printf(m, "alerts:                 %u\n",
1397 		   ssif_get_stat(ssif_info, alerts));
1398 	return 0;
1399 }
1400 
1401 static int smi_stats_proc_open(struct inode *inode, struct file *file)
1402 {
1403 	return single_open(file, smi_stats_proc_show, PDE_DATA(inode));
1404 }
1405 
1406 static const struct file_operations smi_stats_proc_ops = {
1407 	.open		= smi_stats_proc_open,
1408 	.read		= seq_read,
1409 	.llseek		= seq_lseek,
1410 	.release	= single_release,
1411 };
1412 #endif
1413 
1414 static int strcmp_nospace(char *s1, char *s2)
1415 {
1416 	while (*s1 && *s2) {
1417 		while (isspace(*s1))
1418 			s1++;
1419 		while (isspace(*s2))
1420 			s2++;
1421 		if (*s1 > *s2)
1422 			return 1;
1423 		if (*s1 < *s2)
1424 			return -1;
1425 		s1++;
1426 		s2++;
1427 	}
1428 	return 0;
1429 }
1430 
1431 static struct ssif_addr_info *ssif_info_find(unsigned short addr,
1432 					     char *adapter_name,
1433 					     bool match_null_name)
1434 {
1435 	struct ssif_addr_info *info, *found = NULL;
1436 
1437 restart:
1438 	list_for_each_entry(info, &ssif_infos, link) {
1439 		if (info->binfo.addr == addr) {
1440 			if (info->adapter_name || adapter_name) {
1441 				if (!info->adapter_name != !adapter_name) {
1442 					/* One is NULL and one is not */
1443 					continue;
1444 				}
1445 				if (adapter_name &&
1446 				    strcmp_nospace(info->adapter_name,
1447 						   adapter_name))
1448 					/* Names do not match */
1449 					continue;
1450 			}
1451 			found = info;
1452 			break;
1453 		}
1454 	}
1455 
1456 	if (!found && match_null_name) {
1457 		/* Try to get an exact match first, then try with a NULL name */
1458 		adapter_name = NULL;
1459 		match_null_name = false;
1460 		goto restart;
1461 	}
1462 
1463 	return found;
1464 }
1465 
1466 static bool check_acpi(struct ssif_info *ssif_info, struct device *dev)
1467 {
1468 #ifdef CONFIG_ACPI
1469 	acpi_handle acpi_handle;
1470 
1471 	acpi_handle = ACPI_HANDLE(dev);
1472 	if (acpi_handle) {
1473 		ssif_info->addr_source = SI_ACPI;
1474 		ssif_info->addr_info.acpi_info.acpi_handle = acpi_handle;
1475 		return true;
1476 	}
1477 #endif
1478 	return false;
1479 }
1480 
1481 static int find_slave_address(struct i2c_client *client, int slave_addr)
1482 {
1483 #ifdef CONFIG_IPMI_DMI_DECODE
1484 	if (!slave_addr)
1485 		slave_addr = ipmi_dmi_get_slave_addr(
1486 			SI_TYPE_INVALID,
1487 			i2c_adapter_id(client->adapter),
1488 			client->addr);
1489 #endif
1490 
1491 	return slave_addr;
1492 }
1493 
1494 /*
1495  * Global enables we care about.
1496  */
1497 #define GLOBAL_ENABLES_MASK (IPMI_BMC_EVT_MSG_BUFF | IPMI_BMC_RCV_MSG_INTR | \
1498 			     IPMI_BMC_EVT_MSG_INTR)
1499 
1500 static int ssif_probe(struct i2c_client *client, const struct i2c_device_id *id)
1501 {
1502 	unsigned char     msg[3];
1503 	unsigned char     *resp;
1504 	struct ssif_info   *ssif_info;
1505 	int               rv = 0;
1506 	int               len;
1507 	int               i;
1508 	u8		  slave_addr = 0;
1509 	struct ssif_addr_info *addr_info = NULL;
1510 
1511 	resp = kmalloc(IPMI_MAX_MSG_LENGTH, GFP_KERNEL);
1512 	if (!resp)
1513 		return -ENOMEM;
1514 
1515 	ssif_info = kzalloc(sizeof(*ssif_info), GFP_KERNEL);
1516 	if (!ssif_info) {
1517 		kfree(resp);
1518 		return -ENOMEM;
1519 	}
1520 
1521 	if (!check_acpi(ssif_info, &client->dev)) {
1522 		addr_info = ssif_info_find(client->addr, client->adapter->name,
1523 					   true);
1524 		if (!addr_info) {
1525 			/* Must have come in through sysfs. */
1526 			ssif_info->addr_source = SI_HOTMOD;
1527 		} else {
1528 			ssif_info->addr_source = addr_info->addr_src;
1529 			ssif_info->ssif_debug = addr_info->debug;
1530 			ssif_info->addr_info = addr_info->addr_info;
1531 			addr_info->client = client;
1532 			slave_addr = addr_info->slave_addr;
1533 		}
1534 	}
1535 
1536 	slave_addr = find_slave_address(client, slave_addr);
1537 
1538 	pr_info(PFX "Trying %s-specified SSIF interface at i2c address 0x%x, adapter %s, slave address 0x%x\n",
1539 	       ipmi_addr_src_to_str(ssif_info->addr_source),
1540 	       client->addr, client->adapter->name, slave_addr);
1541 
1542 	ssif_info->client = client;
1543 	i2c_set_clientdata(client, ssif_info);
1544 
1545 	/* Now check for system interface capabilities */
1546 	msg[0] = IPMI_NETFN_APP_REQUEST << 2;
1547 	msg[1] = IPMI_GET_SYSTEM_INTERFACE_CAPABILITIES_CMD;
1548 	msg[2] = 0; /* SSIF */
1549 	rv = do_cmd(client, 3, msg, &len, resp);
1550 	if (!rv && (len >= 3) && (resp[2] == 0)) {
1551 		if (len < 7) {
1552 			if (ssif_dbg_probe)
1553 				pr_info(PFX "SSIF info too short: %d\n", len);
1554 			goto no_support;
1555 		}
1556 
1557 		/* Got a good SSIF response, handle it. */
1558 		ssif_info->max_xmit_msg_size = resp[5];
1559 		ssif_info->max_recv_msg_size = resp[6];
1560 		ssif_info->multi_support = (resp[4] >> 6) & 0x3;
1561 		ssif_info->supports_pec = (resp[4] >> 3) & 0x1;
1562 
1563 		/* Sanitize the data */
1564 		switch (ssif_info->multi_support) {
1565 		case SSIF_NO_MULTI:
1566 			if (ssif_info->max_xmit_msg_size > 32)
1567 				ssif_info->max_xmit_msg_size = 32;
1568 			if (ssif_info->max_recv_msg_size > 32)
1569 				ssif_info->max_recv_msg_size = 32;
1570 			break;
1571 
1572 		case SSIF_MULTI_2_PART:
1573 			if (ssif_info->max_xmit_msg_size > 63)
1574 				ssif_info->max_xmit_msg_size = 63;
1575 			if (ssif_info->max_recv_msg_size > 62)
1576 				ssif_info->max_recv_msg_size = 62;
1577 			break;
1578 
1579 		case SSIF_MULTI_n_PART:
1580 			/*
1581 			 * The specification is rather confusing at
1582 			 * this point, but I think I understand what
1583 			 * is meant.  At least I have a workable
1584 			 * solution.  With multi-part messages, you
1585 			 * cannot send a message that is a multiple of
1586 			 * 32-bytes in length, because the start and
1587 			 * middle messages are 32-bytes and the end
1588 			 * message must be at least one byte.  You
1589 			 * can't fudge on an extra byte, that would
1590 			 * screw up things like fru data writes.  So
1591 			 * we limit the length to 63 bytes.  That way
1592 			 * a 32-byte message gets sent as a single
1593 			 * part.  A larger message will be a 32-byte
1594 			 * start and the next message is always going
1595 			 * to be 1-31 bytes in length.  Not ideal, but
1596 			 * it should work.
1597 			 */
1598 			if (ssif_info->max_xmit_msg_size > 63)
1599 				ssif_info->max_xmit_msg_size = 63;
1600 			break;
1601 
1602 		default:
1603 			/* Data is not sane, just give up. */
1604 			goto no_support;
1605 		}
1606 	} else {
1607  no_support:
1608 		/* Assume no multi-part or PEC support */
1609 		pr_info(PFX "Error fetching SSIF: %d %d %2.2x, your system probably doesn't support this command so using defaults\n",
1610 		       rv, len, resp[2]);
1611 
1612 		ssif_info->max_xmit_msg_size = 32;
1613 		ssif_info->max_recv_msg_size = 32;
1614 		ssif_info->multi_support = SSIF_NO_MULTI;
1615 		ssif_info->supports_pec = 0;
1616 	}
1617 
1618 	/* Make sure the NMI timeout is cleared. */
1619 	msg[0] = IPMI_NETFN_APP_REQUEST << 2;
1620 	msg[1] = IPMI_CLEAR_MSG_FLAGS_CMD;
1621 	msg[2] = WDT_PRE_TIMEOUT_INT;
1622 	rv = do_cmd(client, 3, msg, &len, resp);
1623 	if (rv || (len < 3) || (resp[2] != 0))
1624 		pr_warn(PFX "Unable to clear message flags: %d %d %2.2x\n",
1625 			rv, len, resp[2]);
1626 
1627 	/* Attempt to enable the event buffer. */
1628 	msg[0] = IPMI_NETFN_APP_REQUEST << 2;
1629 	msg[1] = IPMI_GET_BMC_GLOBAL_ENABLES_CMD;
1630 	rv = do_cmd(client, 2, msg, &len, resp);
1631 	if (rv || (len < 4) || (resp[2] != 0)) {
1632 		pr_warn(PFX "Error getting global enables: %d %d %2.2x\n",
1633 			rv, len, resp[2]);
1634 		rv = 0; /* Not fatal */
1635 		goto found;
1636 	}
1637 
1638 	ssif_info->global_enables = resp[3];
1639 
1640 	if (resp[3] & IPMI_BMC_EVT_MSG_BUFF) {
1641 		ssif_info->has_event_buffer = true;
1642 		/* buffer is already enabled, nothing to do. */
1643 		goto found;
1644 	}
1645 
1646 	msg[0] = IPMI_NETFN_APP_REQUEST << 2;
1647 	msg[1] = IPMI_SET_BMC_GLOBAL_ENABLES_CMD;
1648 	msg[2] = ssif_info->global_enables | IPMI_BMC_EVT_MSG_BUFF;
1649 	rv = do_cmd(client, 3, msg, &len, resp);
1650 	if (rv || (len < 2)) {
1651 		pr_warn(PFX "Error setting global enables: %d %d %2.2x\n",
1652 			rv, len, resp[2]);
1653 		rv = 0; /* Not fatal */
1654 		goto found;
1655 	}
1656 
1657 	if (resp[2] == 0) {
1658 		/* A successful return means the event buffer is supported. */
1659 		ssif_info->has_event_buffer = true;
1660 		ssif_info->global_enables |= IPMI_BMC_EVT_MSG_BUFF;
1661 	}
1662 
1663 	/* Some systems don't behave well if you enable alerts. */
1664 	if (alerts_broken)
1665 		goto found;
1666 
1667 	msg[0] = IPMI_NETFN_APP_REQUEST << 2;
1668 	msg[1] = IPMI_SET_BMC_GLOBAL_ENABLES_CMD;
1669 	msg[2] = ssif_info->global_enables | IPMI_BMC_RCV_MSG_INTR;
1670 	rv = do_cmd(client, 3, msg, &len, resp);
1671 	if (rv || (len < 2)) {
1672 		pr_warn(PFX "Error setting global enables: %d %d %2.2x\n",
1673 			rv, len, resp[2]);
1674 		rv = 0; /* Not fatal */
1675 		goto found;
1676 	}
1677 
1678 	if (resp[2] == 0) {
1679 		/* A successful return means the alert is supported. */
1680 		ssif_info->supports_alert = true;
1681 		ssif_info->global_enables |= IPMI_BMC_RCV_MSG_INTR;
1682 	}
1683 
1684  found:
1685 	ssif_info->intf_num = atomic_inc_return(&next_intf);
1686 
1687 	if (ssif_dbg_probe) {
1688 		pr_info("ssif_probe: i2c_probe found device at i2c address %x\n",
1689 			client->addr);
1690 	}
1691 
1692 	spin_lock_init(&ssif_info->lock);
1693 	ssif_info->ssif_state = SSIF_NORMAL;
1694 	timer_setup(&ssif_info->retry_timer, retry_timeout, 0);
1695 
1696 	for (i = 0; i < SSIF_NUM_STATS; i++)
1697 		atomic_set(&ssif_info->stats[i], 0);
1698 
1699 	if (ssif_info->supports_pec)
1700 		ssif_info->client->flags |= I2C_CLIENT_PEC;
1701 
1702 	ssif_info->handlers.owner = THIS_MODULE;
1703 	ssif_info->handlers.start_processing = ssif_start_processing;
1704 	ssif_info->handlers.get_smi_info = get_smi_info;
1705 	ssif_info->handlers.sender = sender;
1706 	ssif_info->handlers.request_events = request_events;
1707 	ssif_info->handlers.inc_usecount = inc_usecount;
1708 	ssif_info->handlers.dec_usecount = dec_usecount;
1709 
1710 	{
1711 		unsigned int thread_num;
1712 
1713 		thread_num = ((i2c_adapter_id(ssif_info->client->adapter)
1714 			       << 8) |
1715 			      ssif_info->client->addr);
1716 		init_completion(&ssif_info->wake_thread);
1717 		ssif_info->thread = kthread_run(ipmi_ssif_thread, ssif_info,
1718 					       "kssif%4.4x", thread_num);
1719 		if (IS_ERR(ssif_info->thread)) {
1720 			rv = PTR_ERR(ssif_info->thread);
1721 			dev_notice(&ssif_info->client->dev,
1722 				   "Could not start kernel thread: error %d\n",
1723 				   rv);
1724 			goto out;
1725 		}
1726 	}
1727 
1728 	dev_set_drvdata(&ssif_info->client->dev, ssif_info);
1729 	rv = device_add_group(&ssif_info->client->dev,
1730 			      &ipmi_ssif_dev_attr_group);
1731 	if (rv) {
1732 		dev_err(&ssif_info->client->dev,
1733 			"Unable to add device attributes: error %d\n",
1734 			rv);
1735 		goto out;
1736 	}
1737 
1738 	rv = ipmi_register_smi(&ssif_info->handlers,
1739 			       ssif_info,
1740 			       &ssif_info->client->dev,
1741 			       slave_addr);
1742 	 if (rv) {
1743 		pr_err(PFX "Unable to register device: error %d\n", rv);
1744 		goto out_remove_attr;
1745 	}
1746 
1747 #ifdef CONFIG_IPMI_PROC_INTERFACE
1748 	rv = ipmi_smi_add_proc_entry(ssif_info->intf, "type",
1749 				     &smi_type_proc_ops,
1750 				     ssif_info);
1751 	if (rv) {
1752 		pr_err(PFX "Unable to create proc entry: %d\n", rv);
1753 		goto out_err_unreg;
1754 	}
1755 
1756 	rv = ipmi_smi_add_proc_entry(ssif_info->intf, "ssif_stats",
1757 				     &smi_stats_proc_ops,
1758 				     ssif_info);
1759 	if (rv) {
1760 		pr_err(PFX "Unable to create proc entry: %d\n", rv);
1761 		goto out_err_unreg;
1762 	}
1763 #endif
1764 
1765  out:
1766 	if (rv) {
1767 		/*
1768 		 * Note that if addr_info->client is assigned, we
1769 		 * leave it.  The i2c client hangs around even if we
1770 		 * return a failure here, and the failure here is not
1771 		 * propagated back to the i2c code.  This seems to be
1772 		 * design intent, strange as it may be.  But if we
1773 		 * don't leave it, ssif_platform_remove will not remove
1774 		 * the client like it should.
1775 		 */
1776 		dev_err(&client->dev, "Unable to start IPMI SSIF: %d\n", rv);
1777 		kfree(ssif_info);
1778 	}
1779 	kfree(resp);
1780 	return rv;
1781 
1782 #ifdef CONFIG_IPMI_PROC_INTERFACE
1783 out_err_unreg:
1784 	ipmi_unregister_smi(ssif_info->intf);
1785 #endif
1786 
1787 out_remove_attr:
1788 	device_remove_group(&ssif_info->client->dev, &ipmi_ssif_dev_attr_group);
1789 	dev_set_drvdata(&ssif_info->client->dev, NULL);
1790 	goto out;
1791 }
1792 
1793 static int ssif_adapter_handler(struct device *adev, void *opaque)
1794 {
1795 	struct ssif_addr_info *addr_info = opaque;
1796 
1797 	if (adev->type != &i2c_adapter_type)
1798 		return 0;
1799 
1800 	i2c_new_device(to_i2c_adapter(adev), &addr_info->binfo);
1801 
1802 	if (!addr_info->adapter_name)
1803 		return 1; /* Only try the first I2C adapter by default. */
1804 	return 0;
1805 }
1806 
1807 static int new_ssif_client(int addr, char *adapter_name,
1808 			   int debug, int slave_addr,
1809 			   enum ipmi_addr_src addr_src,
1810 			   struct device *dev)
1811 {
1812 	struct ssif_addr_info *addr_info;
1813 	int rv = 0;
1814 
1815 	mutex_lock(&ssif_infos_mutex);
1816 	if (ssif_info_find(addr, adapter_name, false)) {
1817 		rv = -EEXIST;
1818 		goto out_unlock;
1819 	}
1820 
1821 	addr_info = kzalloc(sizeof(*addr_info), GFP_KERNEL);
1822 	if (!addr_info) {
1823 		rv = -ENOMEM;
1824 		goto out_unlock;
1825 	}
1826 
1827 	if (adapter_name) {
1828 		addr_info->adapter_name = kstrdup(adapter_name, GFP_KERNEL);
1829 		if (!addr_info->adapter_name) {
1830 			kfree(addr_info);
1831 			rv = -ENOMEM;
1832 			goto out_unlock;
1833 		}
1834 	}
1835 
1836 	strncpy(addr_info->binfo.type, DEVICE_NAME,
1837 		sizeof(addr_info->binfo.type));
1838 	addr_info->binfo.addr = addr;
1839 	addr_info->binfo.platform_data = addr_info;
1840 	addr_info->debug = debug;
1841 	addr_info->slave_addr = slave_addr;
1842 	addr_info->addr_src = addr_src;
1843 	addr_info->dev = dev;
1844 
1845 	if (dev)
1846 		dev_set_drvdata(dev, addr_info);
1847 
1848 	list_add_tail(&addr_info->link, &ssif_infos);
1849 
1850 	if (initialized)
1851 		i2c_for_each_dev(addr_info, ssif_adapter_handler);
1852 	/* Otherwise address list will get it */
1853 
1854 out_unlock:
1855 	mutex_unlock(&ssif_infos_mutex);
1856 	return rv;
1857 }
1858 
1859 static void free_ssif_clients(void)
1860 {
1861 	struct ssif_addr_info *info, *tmp;
1862 
1863 	mutex_lock(&ssif_infos_mutex);
1864 	list_for_each_entry_safe(info, tmp, &ssif_infos, link) {
1865 		list_del(&info->link);
1866 		kfree(info->adapter_name);
1867 		kfree(info);
1868 	}
1869 	mutex_unlock(&ssif_infos_mutex);
1870 }
1871 
1872 static unsigned short *ssif_address_list(void)
1873 {
1874 	struct ssif_addr_info *info;
1875 	unsigned int count = 0, i;
1876 	unsigned short *address_list;
1877 
1878 	list_for_each_entry(info, &ssif_infos, link)
1879 		count++;
1880 
1881 	address_list = kzalloc(sizeof(*address_list) * (count + 1), GFP_KERNEL);
1882 	if (!address_list)
1883 		return NULL;
1884 
1885 	i = 0;
1886 	list_for_each_entry(info, &ssif_infos, link) {
1887 		unsigned short addr = info->binfo.addr;
1888 		int j;
1889 
1890 		for (j = 0; j < i; j++) {
1891 			if (address_list[j] == addr)
1892 				goto skip_addr;
1893 		}
1894 		address_list[i] = addr;
1895 skip_addr:
1896 		i++;
1897 	}
1898 	address_list[i] = I2C_CLIENT_END;
1899 
1900 	return address_list;
1901 }
1902 
1903 #ifdef CONFIG_ACPI
1904 static const struct acpi_device_id ssif_acpi_match[] = {
1905 	{ "IPI0001", 0 },
1906 	{ },
1907 };
1908 MODULE_DEVICE_TABLE(acpi, ssif_acpi_match);
1909 
1910 /*
1911  * Once we get an ACPI failure, we don't try any more, because we go
1912  * through the tables sequentially.  Once we don't find a table, there
1913  * are no more.
1914  */
1915 static int acpi_failure;
1916 
1917 /*
1918  * Defined in the IPMI 2.0 spec.
1919  */
1920 struct SPMITable {
1921 	s8	Signature[4];
1922 	u32	Length;
1923 	u8	Revision;
1924 	u8	Checksum;
1925 	s8	OEMID[6];
1926 	s8	OEMTableID[8];
1927 	s8	OEMRevision[4];
1928 	s8	CreatorID[4];
1929 	s8	CreatorRevision[4];
1930 	u8	InterfaceType;
1931 	u8	IPMIlegacy;
1932 	s16	SpecificationRevision;
1933 
1934 	/*
1935 	 * Bit 0 - SCI interrupt supported
1936 	 * Bit 1 - I/O APIC/SAPIC
1937 	 */
1938 	u8	InterruptType;
1939 
1940 	/*
1941 	 * If bit 0 of InterruptType is set, then this is the SCI
1942 	 * interrupt in the GPEx_STS register.
1943 	 */
1944 	u8	GPE;
1945 
1946 	s16	Reserved;
1947 
1948 	/*
1949 	 * If bit 1 of InterruptType is set, then this is the I/O
1950 	 * APIC/SAPIC interrupt.
1951 	 */
1952 	u32	GlobalSystemInterrupt;
1953 
1954 	/* The actual register address. */
1955 	struct acpi_generic_address addr;
1956 
1957 	u8	UID[4];
1958 
1959 	s8      spmi_id[1]; /* A '\0' terminated array starts here. */
1960 };
1961 
1962 static int try_init_spmi(struct SPMITable *spmi)
1963 {
1964 	unsigned short myaddr;
1965 
1966 	if (num_addrs >= MAX_SSIF_BMCS)
1967 		return -1;
1968 
1969 	if (spmi->IPMIlegacy != 1) {
1970 		pr_warn("IPMI: Bad SPMI legacy: %d\n", spmi->IPMIlegacy);
1971 		return -ENODEV;
1972 	}
1973 
1974 	if (spmi->InterfaceType != 4)
1975 		return -ENODEV;
1976 
1977 	if (spmi->addr.space_id != ACPI_ADR_SPACE_SMBUS) {
1978 		pr_warn(PFX "Invalid ACPI SSIF I/O Address type: %d\n",
1979 			spmi->addr.space_id);
1980 		return -EIO;
1981 	}
1982 
1983 	myaddr = spmi->addr.address & 0x7f;
1984 
1985 	return new_ssif_client(myaddr, NULL, 0, 0, SI_SPMI, NULL);
1986 }
1987 
1988 static void spmi_find_bmc(void)
1989 {
1990 	acpi_status      status;
1991 	struct SPMITable *spmi;
1992 	int              i;
1993 
1994 	if (acpi_disabled)
1995 		return;
1996 
1997 	if (acpi_failure)
1998 		return;
1999 
2000 	for (i = 0; ; i++) {
2001 		status = acpi_get_table(ACPI_SIG_SPMI, i+1,
2002 					(struct acpi_table_header **)&spmi);
2003 		if (status != AE_OK)
2004 			return;
2005 
2006 		try_init_spmi(spmi);
2007 	}
2008 }
2009 #else
2010 static void spmi_find_bmc(void) { }
2011 #endif
2012 
2013 #ifdef CONFIG_DMI
2014 static int dmi_ipmi_probe(struct platform_device *pdev)
2015 {
2016 	u8 slave_addr = 0;
2017 	u16 i2c_addr;
2018 	int rv;
2019 
2020 	if (!ssif_trydmi)
2021 		return -ENODEV;
2022 
2023 	rv = device_property_read_u16(&pdev->dev, "i2c-addr", &i2c_addr);
2024 	if (rv) {
2025 		dev_warn(&pdev->dev, PFX "No i2c-addr property\n");
2026 		return -ENODEV;
2027 	}
2028 
2029 	rv = device_property_read_u8(&pdev->dev, "slave-addr", &slave_addr);
2030 	if (rv)
2031 		dev_warn(&pdev->dev, "device has no slave-addr property");
2032 
2033 	return new_ssif_client(i2c_addr, NULL, 0,
2034 			       slave_addr, SI_SMBIOS, &pdev->dev);
2035 }
2036 #else
2037 static int dmi_ipmi_probe(struct platform_device *pdev)
2038 {
2039 	return -ENODEV;
2040 }
2041 #endif
2042 
2043 static const struct i2c_device_id ssif_id[] = {
2044 	{ DEVICE_NAME, 0 },
2045 	{ }
2046 };
2047 MODULE_DEVICE_TABLE(i2c, ssif_id);
2048 
2049 static struct i2c_driver ssif_i2c_driver = {
2050 	.class		= I2C_CLASS_HWMON,
2051 	.driver		= {
2052 		.name			= DEVICE_NAME
2053 	},
2054 	.probe		= ssif_probe,
2055 	.remove		= ssif_remove,
2056 	.alert		= ssif_alert,
2057 	.id_table	= ssif_id,
2058 	.detect		= ssif_detect
2059 };
2060 
2061 static int ssif_platform_probe(struct platform_device *dev)
2062 {
2063 	return dmi_ipmi_probe(dev);
2064 }
2065 
2066 static int ssif_platform_remove(struct platform_device *dev)
2067 {
2068 	struct ssif_addr_info *addr_info = dev_get_drvdata(&dev->dev);
2069 
2070 	if (!addr_info)
2071 		return 0;
2072 
2073 	mutex_lock(&ssif_infos_mutex);
2074 	if (addr_info->client)
2075 		i2c_unregister_device(addr_info->client);
2076 
2077 	list_del(&addr_info->link);
2078 	kfree(addr_info);
2079 	mutex_unlock(&ssif_infos_mutex);
2080 	return 0;
2081 }
2082 
2083 static struct platform_driver ipmi_driver = {
2084 	.driver = {
2085 		.name = DEVICE_NAME,
2086 	},
2087 	.probe		= ssif_platform_probe,
2088 	.remove		= ssif_platform_remove,
2089 };
2090 
2091 static int init_ipmi_ssif(void)
2092 {
2093 	int i;
2094 	int rv;
2095 
2096 	if (initialized)
2097 		return 0;
2098 
2099 	pr_info("IPMI SSIF Interface driver\n");
2100 
2101 	/* build list for i2c from addr list */
2102 	for (i = 0; i < num_addrs; i++) {
2103 		rv = new_ssif_client(addr[i], adapter_name[i],
2104 				     dbg[i], slave_addrs[i],
2105 				     SI_HARDCODED, NULL);
2106 		if (rv)
2107 			pr_err(PFX
2108 			       "Couldn't add hardcoded device at addr 0x%x\n",
2109 			       addr[i]);
2110 	}
2111 
2112 	if (ssif_tryacpi)
2113 		ssif_i2c_driver.driver.acpi_match_table	=
2114 			ACPI_PTR(ssif_acpi_match);
2115 
2116 	if (ssif_tryacpi)
2117 		spmi_find_bmc();
2118 
2119 	if (ssif_trydmi) {
2120 		rv = platform_driver_register(&ipmi_driver);
2121 		if (rv)
2122 			pr_err(PFX "Unable to register driver: %d\n", rv);
2123 	}
2124 
2125 	ssif_i2c_driver.address_list = ssif_address_list();
2126 
2127 	rv = i2c_add_driver(&ssif_i2c_driver);
2128 	if (!rv)
2129 		initialized = true;
2130 
2131 	return rv;
2132 }
2133 module_init(init_ipmi_ssif);
2134 
2135 static void cleanup_ipmi_ssif(void)
2136 {
2137 	if (!initialized)
2138 		return;
2139 
2140 	initialized = false;
2141 
2142 	i2c_del_driver(&ssif_i2c_driver);
2143 
2144 	platform_driver_unregister(&ipmi_driver);
2145 
2146 	free_ssif_clients();
2147 }
2148 module_exit(cleanup_ipmi_ssif);
2149 
2150 MODULE_ALIAS("platform:dmi-ipmi-ssif");
2151 MODULE_AUTHOR("Todd C Davis <todd.c.davis@intel.com>, Corey Minyard <minyard@acm.org>");
2152 MODULE_DESCRIPTION("IPMI driver for management controllers on a SMBus");
2153 MODULE_LICENSE("GPL");
2154