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1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (c) 2003-2018, Intel Corporation. All rights reserved.
4  * Intel Management Engine Interface (Intel MEI) Linux driver
5  */
6 
7 #include <linux/export.h>
8 #include <linux/kthread.h>
9 #include <linux/interrupt.h>
10 #include <linux/fs.h>
11 #include <linux/jiffies.h>
12 #include <linux/slab.h>
13 #include <linux/pm_runtime.h>
14 
15 #include <linux/mei.h>
16 
17 #include "mei_dev.h"
18 #include "hbm.h"
19 #include "client.h"
20 
21 
22 /**
23  * mei_irq_compl_handler - dispatch complete handlers
24  *	for the completed callbacks
25  *
26  * @dev: mei device
27  * @cmpl_list: list of completed cbs
28  */
mei_irq_compl_handler(struct mei_device * dev,struct list_head * cmpl_list)29 void mei_irq_compl_handler(struct mei_device *dev, struct list_head *cmpl_list)
30 {
31 	struct mei_cl_cb *cb, *next;
32 	struct mei_cl *cl;
33 
34 	list_for_each_entry_safe(cb, next, cmpl_list, list) {
35 		cl = cb->cl;
36 		list_del_init(&cb->list);
37 
38 		dev_dbg(dev->dev, "completing call back.\n");
39 		mei_cl_complete(cl, cb);
40 	}
41 }
42 EXPORT_SYMBOL_GPL(mei_irq_compl_handler);
43 
44 /**
45  * mei_cl_hbm_equal - check if hbm is addressed to the client
46  *
47  * @cl: host client
48  * @mei_hdr: header of mei client message
49  *
50  * Return: true if matches, false otherwise
51  */
mei_cl_hbm_equal(struct mei_cl * cl,struct mei_msg_hdr * mei_hdr)52 static inline int mei_cl_hbm_equal(struct mei_cl *cl,
53 			struct mei_msg_hdr *mei_hdr)
54 {
55 	return  mei_cl_host_addr(cl) == mei_hdr->host_addr &&
56 		mei_cl_me_id(cl) == mei_hdr->me_addr;
57 }
58 
59 /**
60  * mei_irq_discard_msg  - discard received message
61  *
62  * @dev: mei device
63  * @hdr: message header
64  * @discard_len: the length of the message to discard (excluding header)
65  */
mei_irq_discard_msg(struct mei_device * dev,struct mei_msg_hdr * hdr,size_t discard_len)66 static void mei_irq_discard_msg(struct mei_device *dev, struct mei_msg_hdr *hdr,
67 				size_t discard_len)
68 {
69 	if (hdr->dma_ring) {
70 		mei_dma_ring_read(dev, NULL,
71 				  hdr->extension[dev->rd_msg_hdr_count - 2]);
72 		discard_len = 0;
73 	}
74 	/*
75 	 * no need to check for size as it is guarantied
76 	 * that length fits into rd_msg_buf
77 	 */
78 	mei_read_slots(dev, dev->rd_msg_buf, discard_len);
79 	dev_dbg(dev->dev, "discarding message " MEI_HDR_FMT "\n",
80 		MEI_HDR_PRM(hdr));
81 }
82 
83 /**
84  * mei_cl_irq_read_msg - process client message
85  *
86  * @cl: reading client
87  * @mei_hdr: header of mei client message
88  * @meta: extend meta header
89  * @cmpl_list: completion list
90  *
91  * Return: always 0
92  */
mei_cl_irq_read_msg(struct mei_cl * cl,struct mei_msg_hdr * mei_hdr,struct mei_ext_meta_hdr * meta,struct list_head * cmpl_list)93 static int mei_cl_irq_read_msg(struct mei_cl *cl,
94 			       struct mei_msg_hdr *mei_hdr,
95 			       struct mei_ext_meta_hdr *meta,
96 			       struct list_head *cmpl_list)
97 {
98 	struct mei_device *dev = cl->dev;
99 	struct mei_cl_cb *cb;
100 
101 	size_t buf_sz;
102 	u32 length;
103 	int ext_len;
104 
105 	length = mei_hdr->length;
106 	ext_len = 0;
107 	if (mei_hdr->extended) {
108 		ext_len = sizeof(*meta) + mei_slots2data(meta->size);
109 		length -= ext_len;
110 	}
111 
112 	cb = list_first_entry_or_null(&cl->rd_pending, struct mei_cl_cb, list);
113 	if (!cb) {
114 		if (!mei_cl_is_fixed_address(cl)) {
115 			cl_err(dev, cl, "pending read cb not found\n");
116 			goto discard;
117 		}
118 		cb = mei_cl_alloc_cb(cl, mei_cl_mtu(cl), MEI_FOP_READ, cl->fp);
119 		if (!cb)
120 			goto discard;
121 		list_add_tail(&cb->list, &cl->rd_pending);
122 	}
123 
124 	if (mei_hdr->extended) {
125 		struct mei_ext_hdr *ext;
126 		struct mei_ext_hdr *vtag = NULL;
127 
128 		ext = mei_ext_begin(meta);
129 		do {
130 			switch (ext->type) {
131 			case MEI_EXT_HDR_VTAG:
132 				vtag = ext;
133 				break;
134 			case MEI_EXT_HDR_NONE:
135 				fallthrough;
136 			default:
137 				cb->status = -EPROTO;
138 				break;
139 			}
140 
141 			ext = mei_ext_next(ext);
142 		} while (!mei_ext_last(meta, ext));
143 
144 		if (!vtag) {
145 			cl_dbg(dev, cl, "vtag not found in extended header.\n");
146 			cb->status = -EPROTO;
147 			goto discard;
148 		}
149 
150 		cl_dbg(dev, cl, "vtag: %d\n", vtag->ext_payload[0]);
151 		if (cb->vtag && cb->vtag != vtag->ext_payload[0]) {
152 			cl_err(dev, cl, "mismatched tag: %d != %d\n",
153 			       cb->vtag, vtag->ext_payload[0]);
154 			cb->status = -EPROTO;
155 			goto discard;
156 		}
157 		cb->vtag = vtag->ext_payload[0];
158 	}
159 
160 	if (!mei_cl_is_connected(cl)) {
161 		cl_dbg(dev, cl, "not connected\n");
162 		cb->status = -ENODEV;
163 		goto discard;
164 	}
165 
166 	if (mei_hdr->dma_ring)
167 		length = mei_hdr->extension[mei_data2slots(ext_len)];
168 
169 	buf_sz = length + cb->buf_idx;
170 	/* catch for integer overflow */
171 	if (buf_sz < cb->buf_idx) {
172 		cl_err(dev, cl, "message is too big len %d idx %zu\n",
173 		       length, cb->buf_idx);
174 		cb->status = -EMSGSIZE;
175 		goto discard;
176 	}
177 
178 	if (cb->buf.size < buf_sz) {
179 		cl_dbg(dev, cl, "message overflow. size %zu len %d idx %zu\n",
180 			cb->buf.size, length, cb->buf_idx);
181 		cb->status = -EMSGSIZE;
182 		goto discard;
183 	}
184 
185 	if (mei_hdr->dma_ring) {
186 		mei_dma_ring_read(dev, cb->buf.data + cb->buf_idx, length);
187 		/*  for DMA read 0 length to generate interrupt to the device */
188 		mei_read_slots(dev, cb->buf.data + cb->buf_idx, 0);
189 	} else {
190 		mei_read_slots(dev, cb->buf.data + cb->buf_idx, length);
191 	}
192 
193 	cb->buf_idx += length;
194 
195 	if (mei_hdr->msg_complete) {
196 		cl_dbg(dev, cl, "completed read length = %zu\n", cb->buf_idx);
197 		list_move_tail(&cb->list, cmpl_list);
198 	} else {
199 		pm_runtime_mark_last_busy(dev->dev);
200 		pm_request_autosuspend(dev->dev);
201 	}
202 
203 	return 0;
204 
205 discard:
206 	if (cb)
207 		list_move_tail(&cb->list, cmpl_list);
208 	mei_irq_discard_msg(dev, mei_hdr, length);
209 	return 0;
210 }
211 
212 /**
213  * mei_cl_irq_disconnect_rsp - send disconnection response message
214  *
215  * @cl: client
216  * @cb: callback block.
217  * @cmpl_list: complete list.
218  *
219  * Return: 0, OK; otherwise, error.
220  */
mei_cl_irq_disconnect_rsp(struct mei_cl * cl,struct mei_cl_cb * cb,struct list_head * cmpl_list)221 static int mei_cl_irq_disconnect_rsp(struct mei_cl *cl, struct mei_cl_cb *cb,
222 				     struct list_head *cmpl_list)
223 {
224 	struct mei_device *dev = cl->dev;
225 	u32 msg_slots;
226 	int slots;
227 	int ret;
228 
229 	msg_slots = mei_hbm2slots(sizeof(struct hbm_client_connect_response));
230 	slots = mei_hbuf_empty_slots(dev);
231 	if (slots < 0)
232 		return -EOVERFLOW;
233 
234 	if ((u32)slots < msg_slots)
235 		return -EMSGSIZE;
236 
237 	ret = mei_hbm_cl_disconnect_rsp(dev, cl);
238 	list_move_tail(&cb->list, cmpl_list);
239 
240 	return ret;
241 }
242 
243 /**
244  * mei_cl_irq_read - processes client read related operation from the
245  *	interrupt thread context - request for flow control credits
246  *
247  * @cl: client
248  * @cb: callback block.
249  * @cmpl_list: complete list.
250  *
251  * Return: 0, OK; otherwise, error.
252  */
mei_cl_irq_read(struct mei_cl * cl,struct mei_cl_cb * cb,struct list_head * cmpl_list)253 static int mei_cl_irq_read(struct mei_cl *cl, struct mei_cl_cb *cb,
254 			   struct list_head *cmpl_list)
255 {
256 	struct mei_device *dev = cl->dev;
257 	u32 msg_slots;
258 	int slots;
259 	int ret;
260 
261 	if (!list_empty(&cl->rd_pending))
262 		return 0;
263 
264 	msg_slots = mei_hbm2slots(sizeof(struct hbm_flow_control));
265 	slots = mei_hbuf_empty_slots(dev);
266 	if (slots < 0)
267 		return -EOVERFLOW;
268 
269 	if ((u32)slots < msg_slots)
270 		return -EMSGSIZE;
271 
272 	ret = mei_hbm_cl_flow_control_req(dev, cl);
273 	if (ret) {
274 		cl->status = ret;
275 		cb->buf_idx = 0;
276 		list_move_tail(&cb->list, cmpl_list);
277 		return ret;
278 	}
279 
280 	pm_runtime_mark_last_busy(dev->dev);
281 	pm_request_autosuspend(dev->dev);
282 
283 	list_move_tail(&cb->list, &cl->rd_pending);
284 
285 	return 0;
286 }
287 
hdr_is_hbm(struct mei_msg_hdr * mei_hdr)288 static inline bool hdr_is_hbm(struct mei_msg_hdr *mei_hdr)
289 {
290 	return mei_hdr->host_addr == 0 && mei_hdr->me_addr == 0;
291 }
292 
hdr_is_fixed(struct mei_msg_hdr * mei_hdr)293 static inline bool hdr_is_fixed(struct mei_msg_hdr *mei_hdr)
294 {
295 	return mei_hdr->host_addr == 0 && mei_hdr->me_addr != 0;
296 }
297 
hdr_is_valid(u32 msg_hdr)298 static inline int hdr_is_valid(u32 msg_hdr)
299 {
300 	struct mei_msg_hdr *mei_hdr;
301 	u32 expected_len = 0;
302 
303 	mei_hdr = (struct mei_msg_hdr *)&msg_hdr;
304 	if (!msg_hdr || mei_hdr->reserved)
305 		return -EBADMSG;
306 
307 	if (mei_hdr->dma_ring)
308 		expected_len += MEI_SLOT_SIZE;
309 	if (mei_hdr->extended)
310 		expected_len += MEI_SLOT_SIZE;
311 	if (mei_hdr->length < expected_len)
312 		return -EBADMSG;
313 
314 	return 0;
315 }
316 
317 /**
318  * mei_irq_read_handler - bottom half read routine after ISR to
319  * handle the read processing.
320  *
321  * @dev: the device structure
322  * @cmpl_list: An instance of our list structure
323  * @slots: slots to read.
324  *
325  * Return: 0 on success, <0 on failure.
326  */
mei_irq_read_handler(struct mei_device * dev,struct list_head * cmpl_list,s32 * slots)327 int mei_irq_read_handler(struct mei_device *dev,
328 			 struct list_head *cmpl_list, s32 *slots)
329 {
330 	struct mei_msg_hdr *mei_hdr;
331 	struct mei_ext_meta_hdr *meta_hdr = NULL;
332 	struct mei_cl *cl;
333 	int ret;
334 	u32 ext_meta_hdr_u32;
335 	u32 hdr_size_left;
336 	u32 hdr_size_ext;
337 	int i;
338 	int ext_hdr_end;
339 
340 	if (!dev->rd_msg_hdr[0]) {
341 		dev->rd_msg_hdr[0] = mei_read_hdr(dev);
342 		dev->rd_msg_hdr_count = 1;
343 		(*slots)--;
344 		dev_dbg(dev->dev, "slots =%08x.\n", *slots);
345 
346 		ret = hdr_is_valid(dev->rd_msg_hdr[0]);
347 		if (ret) {
348 			dev_err(dev->dev, "corrupted message header 0x%08X\n",
349 				dev->rd_msg_hdr[0]);
350 			goto end;
351 		}
352 	}
353 
354 	mei_hdr = (struct mei_msg_hdr *)dev->rd_msg_hdr;
355 	dev_dbg(dev->dev, MEI_HDR_FMT, MEI_HDR_PRM(mei_hdr));
356 
357 	if (mei_slots2data(*slots) < mei_hdr->length) {
358 		dev_err(dev->dev, "less data available than length=%08x.\n",
359 				*slots);
360 		/* we can't read the message */
361 		ret = -ENODATA;
362 		goto end;
363 	}
364 
365 	ext_hdr_end = 1;
366 	hdr_size_left = mei_hdr->length;
367 
368 	if (mei_hdr->extended) {
369 		if (!dev->rd_msg_hdr[1]) {
370 			ext_meta_hdr_u32 = mei_read_hdr(dev);
371 			dev->rd_msg_hdr[1] = ext_meta_hdr_u32;
372 			dev->rd_msg_hdr_count++;
373 			(*slots)--;
374 			dev_dbg(dev->dev, "extended header is %08x\n",
375 				ext_meta_hdr_u32);
376 		}
377 		meta_hdr = ((struct mei_ext_meta_hdr *)dev->rd_msg_hdr + 1);
378 		if (check_add_overflow((u32)sizeof(*meta_hdr),
379 				       mei_slots2data(meta_hdr->size),
380 				       &hdr_size_ext)) {
381 			dev_err(dev->dev, "extended message size too big %d\n",
382 				meta_hdr->size);
383 			return -EBADMSG;
384 		}
385 		if (hdr_size_left < hdr_size_ext) {
386 			dev_err(dev->dev, "corrupted message header len %d\n",
387 				mei_hdr->length);
388 			return -EBADMSG;
389 		}
390 		hdr_size_left -= hdr_size_ext;
391 
392 		ext_hdr_end = meta_hdr->size + 2;
393 		for (i = dev->rd_msg_hdr_count; i < ext_hdr_end; i++) {
394 			dev->rd_msg_hdr[i] = mei_read_hdr(dev);
395 			dev_dbg(dev->dev, "extended header %d is %08x\n", i,
396 				dev->rd_msg_hdr[i]);
397 			dev->rd_msg_hdr_count++;
398 			(*slots)--;
399 		}
400 	}
401 
402 	if (mei_hdr->dma_ring) {
403 		if (hdr_size_left != sizeof(dev->rd_msg_hdr[ext_hdr_end])) {
404 			dev_err(dev->dev, "corrupted message header len %d\n",
405 				mei_hdr->length);
406 			return -EBADMSG;
407 		}
408 
409 		dev->rd_msg_hdr[ext_hdr_end] = mei_read_hdr(dev);
410 		dev->rd_msg_hdr_count++;
411 		(*slots)--;
412 		mei_hdr->length -= sizeof(dev->rd_msg_hdr[ext_hdr_end]);
413 	}
414 
415 	/*  HBM message */
416 	if (hdr_is_hbm(mei_hdr)) {
417 		ret = mei_hbm_dispatch(dev, mei_hdr);
418 		if (ret) {
419 			dev_dbg(dev->dev, "mei_hbm_dispatch failed ret = %d\n",
420 					ret);
421 			goto end;
422 		}
423 		goto reset_slots;
424 	}
425 
426 	/* find recipient cl */
427 	list_for_each_entry(cl, &dev->file_list, link) {
428 		if (mei_cl_hbm_equal(cl, mei_hdr)) {
429 			cl_dbg(dev, cl, "got a message\n");
430 			break;
431 		}
432 	}
433 
434 	/* if no recipient cl was found we assume corrupted header */
435 	if (&cl->link == &dev->file_list) {
436 		/* A message for not connected fixed address clients
437 		 * should be silently discarded
438 		 * On power down client may be force cleaned,
439 		 * silently discard such messages
440 		 */
441 		if (hdr_is_fixed(mei_hdr) ||
442 		    dev->dev_state == MEI_DEV_POWER_DOWN) {
443 			mei_irq_discard_msg(dev, mei_hdr, mei_hdr->length);
444 			ret = 0;
445 			goto reset_slots;
446 		}
447 		dev_err(dev->dev, "no destination client found 0x%08X\n",
448 				dev->rd_msg_hdr[0]);
449 		ret = -EBADMSG;
450 		goto end;
451 	}
452 
453 	ret = mei_cl_irq_read_msg(cl, mei_hdr, meta_hdr, cmpl_list);
454 
455 
456 reset_slots:
457 	/* reset the number of slots and header */
458 	memset(dev->rd_msg_hdr, 0, sizeof(dev->rd_msg_hdr));
459 	dev->rd_msg_hdr_count = 0;
460 	*slots = mei_count_full_read_slots(dev);
461 	if (*slots == -EOVERFLOW) {
462 		/* overflow - reset */
463 		dev_err(dev->dev, "resetting due to slots overflow.\n");
464 		/* set the event since message has been read */
465 		ret = -ERANGE;
466 		goto end;
467 	}
468 end:
469 	return ret;
470 }
471 EXPORT_SYMBOL_GPL(mei_irq_read_handler);
472 
473 
474 /**
475  * mei_irq_write_handler -  dispatch write requests
476  *  after irq received
477  *
478  * @dev: the device structure
479  * @cmpl_list: An instance of our list structure
480  *
481  * Return: 0 on success, <0 on failure.
482  */
mei_irq_write_handler(struct mei_device * dev,struct list_head * cmpl_list)483 int mei_irq_write_handler(struct mei_device *dev, struct list_head *cmpl_list)
484 {
485 
486 	struct mei_cl *cl;
487 	struct mei_cl_cb *cb, *next;
488 	s32 slots;
489 	int ret;
490 
491 
492 	if (!mei_hbuf_acquire(dev))
493 		return 0;
494 
495 	slots = mei_hbuf_empty_slots(dev);
496 	if (slots < 0)
497 		return -EOVERFLOW;
498 
499 	if (slots == 0)
500 		return -EMSGSIZE;
501 
502 	/* complete all waiting for write CB */
503 	dev_dbg(dev->dev, "complete all waiting for write cb.\n");
504 
505 	list_for_each_entry_safe(cb, next, &dev->write_waiting_list, list) {
506 		cl = cb->cl;
507 
508 		cl->status = 0;
509 		cl_dbg(dev, cl, "MEI WRITE COMPLETE\n");
510 		cl->writing_state = MEI_WRITE_COMPLETE;
511 		list_move_tail(&cb->list, cmpl_list);
512 	}
513 
514 	/* complete control write list CB */
515 	dev_dbg(dev->dev, "complete control write list cb.\n");
516 	list_for_each_entry_safe(cb, next, &dev->ctrl_wr_list, list) {
517 		cl = cb->cl;
518 		switch (cb->fop_type) {
519 		case MEI_FOP_DISCONNECT:
520 			/* send disconnect message */
521 			ret = mei_cl_irq_disconnect(cl, cb, cmpl_list);
522 			if (ret)
523 				return ret;
524 
525 			break;
526 		case MEI_FOP_READ:
527 			/* send flow control message */
528 			ret = mei_cl_irq_read(cl, cb, cmpl_list);
529 			if (ret)
530 				return ret;
531 
532 			break;
533 		case MEI_FOP_CONNECT:
534 			/* connect message */
535 			ret = mei_cl_irq_connect(cl, cb, cmpl_list);
536 			if (ret)
537 				return ret;
538 
539 			break;
540 		case MEI_FOP_DISCONNECT_RSP:
541 			/* send disconnect resp */
542 			ret = mei_cl_irq_disconnect_rsp(cl, cb, cmpl_list);
543 			if (ret)
544 				return ret;
545 			break;
546 
547 		case MEI_FOP_NOTIFY_START:
548 		case MEI_FOP_NOTIFY_STOP:
549 			ret = mei_cl_irq_notify(cl, cb, cmpl_list);
550 			if (ret)
551 				return ret;
552 			break;
553 		default:
554 			BUG();
555 		}
556 
557 	}
558 	/* complete  write list CB */
559 	dev_dbg(dev->dev, "complete write list cb.\n");
560 	list_for_each_entry_safe(cb, next, &dev->write_list, list) {
561 		cl = cb->cl;
562 		ret = mei_cl_irq_write(cl, cb, cmpl_list);
563 		if (ret)
564 			return ret;
565 	}
566 	return 0;
567 }
568 EXPORT_SYMBOL_GPL(mei_irq_write_handler);
569 
570 
571 /**
572  * mei_connect_timeout  - connect/disconnect timeouts
573  *
574  * @cl: host client
575  */
mei_connect_timeout(struct mei_cl * cl)576 static void mei_connect_timeout(struct mei_cl *cl)
577 {
578 	struct mei_device *dev = cl->dev;
579 
580 	if (cl->state == MEI_FILE_CONNECTING) {
581 		if (dev->hbm_f_dot_supported) {
582 			cl->state = MEI_FILE_DISCONNECT_REQUIRED;
583 			wake_up(&cl->wait);
584 			return;
585 		}
586 	}
587 	mei_reset(dev);
588 }
589 
590 #define MEI_STALL_TIMER_FREQ (2 * HZ)
591 /**
592  * mei_schedule_stall_timer - re-arm stall_timer work
593  *
594  * Schedule stall timer
595  *
596  * @dev: the device structure
597  */
mei_schedule_stall_timer(struct mei_device * dev)598 void mei_schedule_stall_timer(struct mei_device *dev)
599 {
600 	schedule_delayed_work(&dev->timer_work, MEI_STALL_TIMER_FREQ);
601 }
602 
603 /**
604  * mei_timer - timer function.
605  *
606  * @work: pointer to the work_struct structure
607  *
608  */
mei_timer(struct work_struct * work)609 void mei_timer(struct work_struct *work)
610 {
611 	struct mei_cl *cl;
612 	struct mei_device *dev = container_of(work,
613 					struct mei_device, timer_work.work);
614 	bool reschedule_timer = false;
615 
616 	mutex_lock(&dev->device_lock);
617 
618 	/* Catch interrupt stalls during HBM init handshake */
619 	if (dev->dev_state == MEI_DEV_INIT_CLIENTS &&
620 	    dev->hbm_state != MEI_HBM_IDLE) {
621 
622 		if (dev->init_clients_timer) {
623 			if (--dev->init_clients_timer == 0) {
624 				dev_err(dev->dev, "timer: init clients timeout hbm_state = %d.\n",
625 					dev->hbm_state);
626 				mei_reset(dev);
627 				goto out;
628 			}
629 			reschedule_timer = true;
630 		}
631 	}
632 
633 	if (dev->dev_state != MEI_DEV_ENABLED)
634 		goto out;
635 
636 	/*** connect/disconnect timeouts ***/
637 	list_for_each_entry(cl, &dev->file_list, link) {
638 		if (cl->timer_count) {
639 			if (--cl->timer_count == 0) {
640 				dev_err(dev->dev, "timer: connect/disconnect timeout.\n");
641 				mei_connect_timeout(cl);
642 				goto out;
643 			}
644 			reschedule_timer = true;
645 		}
646 	}
647 
648 out:
649 	if (dev->dev_state != MEI_DEV_DISABLED && reschedule_timer)
650 		mei_schedule_stall_timer(dev);
651 
652 	mutex_unlock(&dev->device_lock);
653 }
654