xref: /openbmc/linux/drivers/misc/mei/hw-me.c (revision 3c6a73cc)
1 /*
2  *
3  * Intel Management Engine Interface (Intel MEI) Linux driver
4  * Copyright (c) 2003-2012, Intel Corporation.
5  *
6  * This program is free software; you can redistribute it and/or modify it
7  * under the terms and conditions of the GNU General Public License,
8  * version 2, as published by the Free Software Foundation.
9  *
10  * This program is distributed in the hope it will be useful, but WITHOUT
11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
13  * more details.
14  *
15  */
16 
17 #include <linux/pci.h>
18 
19 #include <linux/kthread.h>
20 #include <linux/interrupt.h>
21 
22 #include "mei_dev.h"
23 #include "hbm.h"
24 
25 #include "hw-me.h"
26 #include "hw-me-regs.h"
27 
28 /**
29  * mei_me_reg_read - Reads 32bit data from the mei device
30  *
31  * @hw: the me hardware structure
32  * @offset: offset from which to read the data
33  *
34  * Return: register value (u32)
35  */
36 static inline u32 mei_me_reg_read(const struct mei_me_hw *hw,
37 			       unsigned long offset)
38 {
39 	return ioread32(hw->mem_addr + offset);
40 }
41 
42 
43 /**
44  * mei_me_reg_write - Writes 32bit data to the mei device
45  *
46  * @hw: the me hardware structure
47  * @offset: offset from which to write the data
48  * @value: register value to write (u32)
49  */
50 static inline void mei_me_reg_write(const struct mei_me_hw *hw,
51 				 unsigned long offset, u32 value)
52 {
53 	iowrite32(value, hw->mem_addr + offset);
54 }
55 
56 /**
57  * mei_me_mecbrw_read - Reads 32bit data from ME circular buffer
58  *  read window register
59  *
60  * @dev: the device structure
61  *
62  * Return: ME_CB_RW register value (u32)
63  */
64 static u32 mei_me_mecbrw_read(const struct mei_device *dev)
65 {
66 	return mei_me_reg_read(to_me_hw(dev), ME_CB_RW);
67 }
68 /**
69  * mei_me_mecsr_read - Reads 32bit data from the ME CSR
70  *
71  * @hw: the me hardware structure
72  *
73  * Return: ME_CSR_HA register value (u32)
74  */
75 static inline u32 mei_me_mecsr_read(const struct mei_me_hw *hw)
76 {
77 	return mei_me_reg_read(hw, ME_CSR_HA);
78 }
79 
80 /**
81  * mei_hcsr_read - Reads 32bit data from the host CSR
82  *
83  * @hw: the me hardware structure
84  *
85  * Return: H_CSR register value (u32)
86  */
87 static inline u32 mei_hcsr_read(const struct mei_me_hw *hw)
88 {
89 	return mei_me_reg_read(hw, H_CSR);
90 }
91 
92 /**
93  * mei_hcsr_set - writes H_CSR register to the mei device,
94  * and ignores the H_IS bit for it is write-one-to-zero.
95  *
96  * @hw: the me hardware structure
97  * @hcsr: new register value
98  */
99 static inline void mei_hcsr_set(struct mei_me_hw *hw, u32 hcsr)
100 {
101 	hcsr &= ~H_IS;
102 	mei_me_reg_write(hw, H_CSR, hcsr);
103 }
104 
105 /**
106  * mei_me_fw_status - read fw status register from pci config space
107  *
108  * @dev: mei device
109  * @fw_status: fw status register values
110  *
111  * Return: 0 on success, error otherwise
112  */
113 static int mei_me_fw_status(struct mei_device *dev,
114 			    struct mei_fw_status *fw_status)
115 {
116 	struct pci_dev *pdev = to_pci_dev(dev->dev);
117 	struct mei_me_hw *hw = to_me_hw(dev);
118 	const struct mei_fw_status *fw_src = &hw->cfg->fw_status;
119 	int ret;
120 	int i;
121 
122 	if (!fw_status)
123 		return -EINVAL;
124 
125 	fw_status->count = fw_src->count;
126 	for (i = 0; i < fw_src->count && i < MEI_FW_STATUS_MAX; i++) {
127 		ret = pci_read_config_dword(pdev,
128 			fw_src->status[i], &fw_status->status[i]);
129 		if (ret)
130 			return ret;
131 	}
132 
133 	return 0;
134 }
135 
136 /**
137  * mei_me_hw_config - configure hw dependent settings
138  *
139  * @dev: mei device
140  */
141 static void mei_me_hw_config(struct mei_device *dev)
142 {
143 	struct mei_me_hw *hw = to_me_hw(dev);
144 	u32 hcsr = mei_hcsr_read(to_me_hw(dev));
145 	/* Doesn't change in runtime */
146 	dev->hbuf_depth = (hcsr & H_CBD) >> 24;
147 
148 	hw->pg_state = MEI_PG_OFF;
149 }
150 
151 /**
152  * mei_me_pg_state  - translate internal pg state
153  *   to the mei power gating state
154  *
155  * @dev:  mei device
156  *
157  * Return: MEI_PG_OFF if aliveness is on and MEI_PG_ON otherwise
158  */
159 static inline enum mei_pg_state mei_me_pg_state(struct mei_device *dev)
160 {
161 	struct mei_me_hw *hw = to_me_hw(dev);
162 
163 	return hw->pg_state;
164 }
165 
166 /**
167  * mei_me_intr_clear - clear and stop interrupts
168  *
169  * @dev: the device structure
170  */
171 static void mei_me_intr_clear(struct mei_device *dev)
172 {
173 	struct mei_me_hw *hw = to_me_hw(dev);
174 	u32 hcsr = mei_hcsr_read(hw);
175 
176 	if ((hcsr & H_IS) == H_IS)
177 		mei_me_reg_write(hw, H_CSR, hcsr);
178 }
179 /**
180  * mei_me_intr_enable - enables mei device interrupts
181  *
182  * @dev: the device structure
183  */
184 static void mei_me_intr_enable(struct mei_device *dev)
185 {
186 	struct mei_me_hw *hw = to_me_hw(dev);
187 	u32 hcsr = mei_hcsr_read(hw);
188 
189 	hcsr |= H_IE;
190 	mei_hcsr_set(hw, hcsr);
191 }
192 
193 /**
194  * mei_me_intr_disable - disables mei device interrupts
195  *
196  * @dev: the device structure
197  */
198 static void mei_me_intr_disable(struct mei_device *dev)
199 {
200 	struct mei_me_hw *hw = to_me_hw(dev);
201 	u32 hcsr = mei_hcsr_read(hw);
202 
203 	hcsr  &= ~H_IE;
204 	mei_hcsr_set(hw, hcsr);
205 }
206 
207 /**
208  * mei_me_hw_reset_release - release device from the reset
209  *
210  * @dev: the device structure
211  */
212 static void mei_me_hw_reset_release(struct mei_device *dev)
213 {
214 	struct mei_me_hw *hw = to_me_hw(dev);
215 	u32 hcsr = mei_hcsr_read(hw);
216 
217 	hcsr |= H_IG;
218 	hcsr &= ~H_RST;
219 	mei_hcsr_set(hw, hcsr);
220 
221 	/* complete this write before we set host ready on another CPU */
222 	mmiowb();
223 }
224 /**
225  * mei_me_hw_reset - resets fw via mei csr register.
226  *
227  * @dev: the device structure
228  * @intr_enable: if interrupt should be enabled after reset.
229  *
230  * Return: always 0
231  */
232 static int mei_me_hw_reset(struct mei_device *dev, bool intr_enable)
233 {
234 	struct mei_me_hw *hw = to_me_hw(dev);
235 	u32 hcsr = mei_hcsr_read(hw);
236 
237 	hcsr |= H_RST | H_IG | H_IS;
238 
239 	if (intr_enable)
240 		hcsr |= H_IE;
241 	else
242 		hcsr &= ~H_IE;
243 
244 	dev->recvd_hw_ready = false;
245 	mei_me_reg_write(hw, H_CSR, hcsr);
246 
247 	/*
248 	 * Host reads the H_CSR once to ensure that the
249 	 * posted write to H_CSR completes.
250 	 */
251 	hcsr = mei_hcsr_read(hw);
252 
253 	if ((hcsr & H_RST) == 0)
254 		dev_warn(dev->dev, "H_RST is not set = 0x%08X", hcsr);
255 
256 	if ((hcsr & H_RDY) == H_RDY)
257 		dev_warn(dev->dev, "H_RDY is not cleared 0x%08X", hcsr);
258 
259 	if (intr_enable == false)
260 		mei_me_hw_reset_release(dev);
261 
262 	return 0;
263 }
264 
265 /**
266  * mei_me_host_set_ready - enable device
267  *
268  * @dev: mei device
269  */
270 static void mei_me_host_set_ready(struct mei_device *dev)
271 {
272 	struct mei_me_hw *hw = to_me_hw(dev);
273 
274 	hw->host_hw_state = mei_hcsr_read(hw);
275 	hw->host_hw_state |= H_IE | H_IG | H_RDY;
276 	mei_hcsr_set(hw, hw->host_hw_state);
277 }
278 
279 /**
280  * mei_me_host_is_ready - check whether the host has turned ready
281  *
282  * @dev: mei device
283  * Return: bool
284  */
285 static bool mei_me_host_is_ready(struct mei_device *dev)
286 {
287 	struct mei_me_hw *hw = to_me_hw(dev);
288 
289 	hw->host_hw_state = mei_hcsr_read(hw);
290 	return (hw->host_hw_state & H_RDY) == H_RDY;
291 }
292 
293 /**
294  * mei_me_hw_is_ready - check whether the me(hw) has turned ready
295  *
296  * @dev: mei device
297  * Return: bool
298  */
299 static bool mei_me_hw_is_ready(struct mei_device *dev)
300 {
301 	struct mei_me_hw *hw = to_me_hw(dev);
302 
303 	hw->me_hw_state = mei_me_mecsr_read(hw);
304 	return (hw->me_hw_state & ME_RDY_HRA) == ME_RDY_HRA;
305 }
306 
307 /**
308  * mei_me_hw_ready_wait - wait until the me(hw) has turned ready
309  *  or timeout is reached
310  *
311  * @dev: mei device
312  * Return: 0 on success, error otherwise
313  */
314 static int mei_me_hw_ready_wait(struct mei_device *dev)
315 {
316 	mutex_unlock(&dev->device_lock);
317 	wait_event_timeout(dev->wait_hw_ready,
318 			dev->recvd_hw_ready,
319 			mei_secs_to_jiffies(MEI_HW_READY_TIMEOUT));
320 	mutex_lock(&dev->device_lock);
321 	if (!dev->recvd_hw_ready) {
322 		dev_err(dev->dev, "wait hw ready failed\n");
323 		return -ETIME;
324 	}
325 
326 	dev->recvd_hw_ready = false;
327 	return 0;
328 }
329 
330 /**
331  * mei_me_hw_start - hw start routine
332  *
333  * @dev: mei device
334  * Return: 0 on success, error otherwise
335  */
336 static int mei_me_hw_start(struct mei_device *dev)
337 {
338 	int ret = mei_me_hw_ready_wait(dev);
339 
340 	if (ret)
341 		return ret;
342 	dev_dbg(dev->dev, "hw is ready\n");
343 
344 	mei_me_host_set_ready(dev);
345 	return ret;
346 }
347 
348 
349 /**
350  * mei_hbuf_filled_slots - gets number of device filled buffer slots
351  *
352  * @dev: the device structure
353  *
354  * Return: number of filled slots
355  */
356 static unsigned char mei_hbuf_filled_slots(struct mei_device *dev)
357 {
358 	struct mei_me_hw *hw = to_me_hw(dev);
359 	char read_ptr, write_ptr;
360 
361 	hw->host_hw_state = mei_hcsr_read(hw);
362 
363 	read_ptr = (char) ((hw->host_hw_state & H_CBRP) >> 8);
364 	write_ptr = (char) ((hw->host_hw_state & H_CBWP) >> 16);
365 
366 	return (unsigned char) (write_ptr - read_ptr);
367 }
368 
369 /**
370  * mei_me_hbuf_is_empty - checks if host buffer is empty.
371  *
372  * @dev: the device structure
373  *
374  * Return: true if empty, false - otherwise.
375  */
376 static bool mei_me_hbuf_is_empty(struct mei_device *dev)
377 {
378 	return mei_hbuf_filled_slots(dev) == 0;
379 }
380 
381 /**
382  * mei_me_hbuf_empty_slots - counts write empty slots.
383  *
384  * @dev: the device structure
385  *
386  * Return: -EOVERFLOW if overflow, otherwise empty slots count
387  */
388 static int mei_me_hbuf_empty_slots(struct mei_device *dev)
389 {
390 	unsigned char filled_slots, empty_slots;
391 
392 	filled_slots = mei_hbuf_filled_slots(dev);
393 	empty_slots = dev->hbuf_depth - filled_slots;
394 
395 	/* check for overflow */
396 	if (filled_slots > dev->hbuf_depth)
397 		return -EOVERFLOW;
398 
399 	return empty_slots;
400 }
401 
402 /**
403  * mei_me_hbuf_max_len - returns size of hw buffer.
404  *
405  * @dev: the device structure
406  *
407  * Return: size of hw buffer in bytes
408  */
409 static size_t mei_me_hbuf_max_len(const struct mei_device *dev)
410 {
411 	return dev->hbuf_depth * sizeof(u32) - sizeof(struct mei_msg_hdr);
412 }
413 
414 
415 /**
416  * mei_me_write_message - writes a message to mei device.
417  *
418  * @dev: the device structure
419  * @header: mei HECI header of message
420  * @buf: message payload will be written
421  *
422  * Return: -EIO if write has failed
423  */
424 static int mei_me_write_message(struct mei_device *dev,
425 			struct mei_msg_hdr *header,
426 			unsigned char *buf)
427 {
428 	struct mei_me_hw *hw = to_me_hw(dev);
429 	unsigned long rem;
430 	unsigned long length = header->length;
431 	u32 *reg_buf = (u32 *)buf;
432 	u32 hcsr;
433 	u32 dw_cnt;
434 	int i;
435 	int empty_slots;
436 
437 	dev_dbg(dev->dev, MEI_HDR_FMT, MEI_HDR_PRM(header));
438 
439 	empty_slots = mei_hbuf_empty_slots(dev);
440 	dev_dbg(dev->dev, "empty slots = %hu.\n", empty_slots);
441 
442 	dw_cnt = mei_data2slots(length);
443 	if (empty_slots < 0 || dw_cnt > empty_slots)
444 		return -EMSGSIZE;
445 
446 	mei_me_reg_write(hw, H_CB_WW, *((u32 *) header));
447 
448 	for (i = 0; i < length / 4; i++)
449 		mei_me_reg_write(hw, H_CB_WW, reg_buf[i]);
450 
451 	rem = length & 0x3;
452 	if (rem > 0) {
453 		u32 reg = 0;
454 
455 		memcpy(&reg, &buf[length - rem], rem);
456 		mei_me_reg_write(hw, H_CB_WW, reg);
457 	}
458 
459 	hcsr = mei_hcsr_read(hw) | H_IG;
460 	mei_hcsr_set(hw, hcsr);
461 	if (!mei_me_hw_is_ready(dev))
462 		return -EIO;
463 
464 	return 0;
465 }
466 
467 /**
468  * mei_me_count_full_read_slots - counts read full slots.
469  *
470  * @dev: the device structure
471  *
472  * Return: -EOVERFLOW if overflow, otherwise filled slots count
473  */
474 static int mei_me_count_full_read_slots(struct mei_device *dev)
475 {
476 	struct mei_me_hw *hw = to_me_hw(dev);
477 	char read_ptr, write_ptr;
478 	unsigned char buffer_depth, filled_slots;
479 
480 	hw->me_hw_state = mei_me_mecsr_read(hw);
481 	buffer_depth = (unsigned char)((hw->me_hw_state & ME_CBD_HRA) >> 24);
482 	read_ptr = (char) ((hw->me_hw_state & ME_CBRP_HRA) >> 8);
483 	write_ptr = (char) ((hw->me_hw_state & ME_CBWP_HRA) >> 16);
484 	filled_slots = (unsigned char) (write_ptr - read_ptr);
485 
486 	/* check for overflow */
487 	if (filled_slots > buffer_depth)
488 		return -EOVERFLOW;
489 
490 	dev_dbg(dev->dev, "filled_slots =%08x\n", filled_slots);
491 	return (int)filled_slots;
492 }
493 
494 /**
495  * mei_me_read_slots - reads a message from mei device.
496  *
497  * @dev: the device structure
498  * @buffer: message buffer will be written
499  * @buffer_length: message size will be read
500  *
501  * Return: always 0
502  */
503 static int mei_me_read_slots(struct mei_device *dev, unsigned char *buffer,
504 		    unsigned long buffer_length)
505 {
506 	struct mei_me_hw *hw = to_me_hw(dev);
507 	u32 *reg_buf = (u32 *)buffer;
508 	u32 hcsr;
509 
510 	for (; buffer_length >= sizeof(u32); buffer_length -= sizeof(u32))
511 		*reg_buf++ = mei_me_mecbrw_read(dev);
512 
513 	if (buffer_length > 0) {
514 		u32 reg = mei_me_mecbrw_read(dev);
515 
516 		memcpy(reg_buf, &reg, buffer_length);
517 	}
518 
519 	hcsr = mei_hcsr_read(hw) | H_IG;
520 	mei_hcsr_set(hw, hcsr);
521 	return 0;
522 }
523 
524 /**
525  * mei_me_pg_enter - write pg enter register
526  *
527  * @dev: the device structure
528  */
529 static void mei_me_pg_enter(struct mei_device *dev)
530 {
531 	struct mei_me_hw *hw = to_me_hw(dev);
532 	u32 reg = mei_me_reg_read(hw, H_HPG_CSR);
533 
534 	reg |= H_HPG_CSR_PGI;
535 	mei_me_reg_write(hw, H_HPG_CSR, reg);
536 }
537 
538 /**
539  * mei_me_pg_exit - write pg exit register
540  *
541  * @dev: the device structure
542  */
543 static void mei_me_pg_exit(struct mei_device *dev)
544 {
545 	struct mei_me_hw *hw = to_me_hw(dev);
546 	u32 reg = mei_me_reg_read(hw, H_HPG_CSR);
547 
548 	WARN(!(reg & H_HPG_CSR_PGI), "PGI is not set\n");
549 
550 	reg |= H_HPG_CSR_PGIHEXR;
551 	mei_me_reg_write(hw, H_HPG_CSR, reg);
552 }
553 
554 /**
555  * mei_me_pg_set_sync - perform pg entry procedure
556  *
557  * @dev: the device structure
558  *
559  * Return: 0 on success an error code otherwise
560  */
561 int mei_me_pg_set_sync(struct mei_device *dev)
562 {
563 	struct mei_me_hw *hw = to_me_hw(dev);
564 	unsigned long timeout = mei_secs_to_jiffies(MEI_PGI_TIMEOUT);
565 	int ret;
566 
567 	dev->pg_event = MEI_PG_EVENT_WAIT;
568 
569 	ret = mei_hbm_pg(dev, MEI_PG_ISOLATION_ENTRY_REQ_CMD);
570 	if (ret)
571 		return ret;
572 
573 	mutex_unlock(&dev->device_lock);
574 	wait_event_timeout(dev->wait_pg,
575 		dev->pg_event == MEI_PG_EVENT_RECEIVED, timeout);
576 	mutex_lock(&dev->device_lock);
577 
578 	if (dev->pg_event == MEI_PG_EVENT_RECEIVED) {
579 		mei_me_pg_enter(dev);
580 		ret = 0;
581 	} else {
582 		ret = -ETIME;
583 	}
584 
585 	dev->pg_event = MEI_PG_EVENT_IDLE;
586 	hw->pg_state = MEI_PG_ON;
587 
588 	return ret;
589 }
590 
591 /**
592  * mei_me_pg_unset_sync - perform pg exit procedure
593  *
594  * @dev: the device structure
595  *
596  * Return: 0 on success an error code otherwise
597  */
598 int mei_me_pg_unset_sync(struct mei_device *dev)
599 {
600 	struct mei_me_hw *hw = to_me_hw(dev);
601 	unsigned long timeout = mei_secs_to_jiffies(MEI_PGI_TIMEOUT);
602 	int ret;
603 
604 	if (dev->pg_event == MEI_PG_EVENT_RECEIVED)
605 		goto reply;
606 
607 	dev->pg_event = MEI_PG_EVENT_WAIT;
608 
609 	mei_me_pg_exit(dev);
610 
611 	mutex_unlock(&dev->device_lock);
612 	wait_event_timeout(dev->wait_pg,
613 		dev->pg_event == MEI_PG_EVENT_RECEIVED, timeout);
614 	mutex_lock(&dev->device_lock);
615 
616 reply:
617 	if (dev->pg_event == MEI_PG_EVENT_RECEIVED)
618 		ret = mei_hbm_pg(dev, MEI_PG_ISOLATION_EXIT_RES_CMD);
619 	else
620 		ret = -ETIME;
621 
622 	dev->pg_event = MEI_PG_EVENT_IDLE;
623 	hw->pg_state = MEI_PG_OFF;
624 
625 	return ret;
626 }
627 
628 /**
629  * mei_me_pg_is_enabled - detect if PG is supported by HW
630  *
631  * @dev: the device structure
632  *
633  * Return: true is pg supported, false otherwise
634  */
635 static bool mei_me_pg_is_enabled(struct mei_device *dev)
636 {
637 	struct mei_me_hw *hw = to_me_hw(dev);
638 	u32 reg = mei_me_reg_read(hw, ME_CSR_HA);
639 
640 	if ((reg & ME_PGIC_HRA) == 0)
641 		goto notsupported;
642 
643 	if (!dev->hbm_f_pg_supported)
644 		goto notsupported;
645 
646 	return true;
647 
648 notsupported:
649 	dev_dbg(dev->dev, "pg: not supported: HGP = %d hbm version %d.%d ?= %d.%d\n",
650 		!!(reg & ME_PGIC_HRA),
651 		dev->version.major_version,
652 		dev->version.minor_version,
653 		HBM_MAJOR_VERSION_PGI,
654 		HBM_MINOR_VERSION_PGI);
655 
656 	return false;
657 }
658 
659 /**
660  * mei_me_irq_quick_handler - The ISR of the MEI device
661  *
662  * @irq: The irq number
663  * @dev_id: pointer to the device structure
664  *
665  * Return: irqreturn_t
666  */
667 
668 irqreturn_t mei_me_irq_quick_handler(int irq, void *dev_id)
669 {
670 	struct mei_device *dev = (struct mei_device *) dev_id;
671 	struct mei_me_hw *hw = to_me_hw(dev);
672 	u32 csr_reg = mei_hcsr_read(hw);
673 
674 	if ((csr_reg & H_IS) != H_IS)
675 		return IRQ_NONE;
676 
677 	/* clear H_IS bit in H_CSR */
678 	mei_me_reg_write(hw, H_CSR, csr_reg);
679 
680 	return IRQ_WAKE_THREAD;
681 }
682 
683 /**
684  * mei_me_irq_thread_handler - function called after ISR to handle the interrupt
685  * processing.
686  *
687  * @irq: The irq number
688  * @dev_id: pointer to the device structure
689  *
690  * Return: irqreturn_t
691  *
692  */
693 irqreturn_t mei_me_irq_thread_handler(int irq, void *dev_id)
694 {
695 	struct mei_device *dev = (struct mei_device *) dev_id;
696 	struct mei_cl_cb complete_list;
697 	s32 slots;
698 	int rets = 0;
699 
700 	dev_dbg(dev->dev, "function called after ISR to handle the interrupt processing.\n");
701 	/* initialize our complete list */
702 	mutex_lock(&dev->device_lock);
703 	mei_io_list_init(&complete_list);
704 
705 	/* Ack the interrupt here
706 	 * In case of MSI we don't go through the quick handler */
707 	if (pci_dev_msi_enabled(to_pci_dev(dev->dev)))
708 		mei_clear_interrupts(dev);
709 
710 	/* check if ME wants a reset */
711 	if (!mei_hw_is_ready(dev) && dev->dev_state != MEI_DEV_RESETTING) {
712 		dev_warn(dev->dev, "FW not ready: resetting.\n");
713 		schedule_work(&dev->reset_work);
714 		goto end;
715 	}
716 
717 	/*  check if we need to start the dev */
718 	if (!mei_host_is_ready(dev)) {
719 		if (mei_hw_is_ready(dev)) {
720 			mei_me_hw_reset_release(dev);
721 			dev_dbg(dev->dev, "we need to start the dev.\n");
722 
723 			dev->recvd_hw_ready = true;
724 			wake_up(&dev->wait_hw_ready);
725 		} else {
726 			dev_dbg(dev->dev, "Spurious Interrupt\n");
727 		}
728 		goto end;
729 	}
730 	/* check slots available for reading */
731 	slots = mei_count_full_read_slots(dev);
732 	while (slots > 0) {
733 		dev_dbg(dev->dev, "slots to read = %08x\n", slots);
734 		rets = mei_irq_read_handler(dev, &complete_list, &slots);
735 		/* There is a race between ME write and interrupt delivery:
736 		 * Not all data is always available immediately after the
737 		 * interrupt, so try to read again on the next interrupt.
738 		 */
739 		if (rets == -ENODATA)
740 			break;
741 
742 		if (rets && dev->dev_state != MEI_DEV_RESETTING) {
743 			dev_err(dev->dev, "mei_irq_read_handler ret = %d.\n",
744 						rets);
745 			schedule_work(&dev->reset_work);
746 			goto end;
747 		}
748 	}
749 
750 	dev->hbuf_is_ready = mei_hbuf_is_ready(dev);
751 
752 	/*
753 	 * During PG handshake only allowed write is the replay to the
754 	 * PG exit message, so block calling write function
755 	 * if the pg state is not idle
756 	 */
757 	if (dev->pg_event == MEI_PG_EVENT_IDLE) {
758 		rets = mei_irq_write_handler(dev, &complete_list);
759 		dev->hbuf_is_ready = mei_hbuf_is_ready(dev);
760 	}
761 
762 	mei_irq_compl_handler(dev, &complete_list);
763 
764 end:
765 	dev_dbg(dev->dev, "interrupt thread end ret = %d\n", rets);
766 	mutex_unlock(&dev->device_lock);
767 	return IRQ_HANDLED;
768 }
769 
770 static const struct mei_hw_ops mei_me_hw_ops = {
771 
772 	.fw_status = mei_me_fw_status,
773 	.pg_state  = mei_me_pg_state,
774 
775 	.host_is_ready = mei_me_host_is_ready,
776 
777 	.hw_is_ready = mei_me_hw_is_ready,
778 	.hw_reset = mei_me_hw_reset,
779 	.hw_config = mei_me_hw_config,
780 	.hw_start = mei_me_hw_start,
781 
782 	.pg_is_enabled = mei_me_pg_is_enabled,
783 
784 	.intr_clear = mei_me_intr_clear,
785 	.intr_enable = mei_me_intr_enable,
786 	.intr_disable = mei_me_intr_disable,
787 
788 	.hbuf_free_slots = mei_me_hbuf_empty_slots,
789 	.hbuf_is_ready = mei_me_hbuf_is_empty,
790 	.hbuf_max_len = mei_me_hbuf_max_len,
791 
792 	.write = mei_me_write_message,
793 
794 	.rdbuf_full_slots = mei_me_count_full_read_slots,
795 	.read_hdr = mei_me_mecbrw_read,
796 	.read = mei_me_read_slots
797 };
798 
799 static bool mei_me_fw_type_nm(struct pci_dev *pdev)
800 {
801 	u32 reg;
802 
803 	pci_read_config_dword(pdev, PCI_CFG_HFS_2, &reg);
804 	/* make sure that bit 9 (NM) is up and bit 10 (DM) is down */
805 	return (reg & 0x600) == 0x200;
806 }
807 
808 #define MEI_CFG_FW_NM                           \
809 	.quirk_probe = mei_me_fw_type_nm
810 
811 static bool mei_me_fw_type_sps(struct pci_dev *pdev)
812 {
813 	u32 reg;
814 	/* Read ME FW Status check for SPS Firmware */
815 	pci_read_config_dword(pdev, PCI_CFG_HFS_1, &reg);
816 	/* if bits [19:16] = 15, running SPS Firmware */
817 	return (reg & 0xf0000) == 0xf0000;
818 }
819 
820 #define MEI_CFG_FW_SPS                           \
821 	.quirk_probe = mei_me_fw_type_sps
822 
823 
824 #define MEI_CFG_LEGACY_HFS                      \
825 	.fw_status.count = 0
826 
827 #define MEI_CFG_ICH_HFS                        \
828 	.fw_status.count = 1,                   \
829 	.fw_status.status[0] = PCI_CFG_HFS_1
830 
831 #define MEI_CFG_PCH_HFS                         \
832 	.fw_status.count = 2,                   \
833 	.fw_status.status[0] = PCI_CFG_HFS_1,   \
834 	.fw_status.status[1] = PCI_CFG_HFS_2
835 
836 
837 /* ICH Legacy devices */
838 const struct mei_cfg mei_me_legacy_cfg = {
839 	MEI_CFG_LEGACY_HFS,
840 };
841 
842 /* ICH devices */
843 const struct mei_cfg mei_me_ich_cfg = {
844 	MEI_CFG_ICH_HFS,
845 };
846 
847 /* PCH devices */
848 const struct mei_cfg mei_me_pch_cfg = {
849 	MEI_CFG_PCH_HFS,
850 };
851 
852 
853 /* PCH Cougar Point and Patsburg with quirk for Node Manager exclusion */
854 const struct mei_cfg mei_me_pch_cpt_pbg_cfg = {
855 	MEI_CFG_PCH_HFS,
856 	MEI_CFG_FW_NM,
857 };
858 
859 /* PCH Lynx Point with quirk for SPS Firmware exclusion */
860 const struct mei_cfg mei_me_lpt_cfg = {
861 	MEI_CFG_PCH_HFS,
862 	MEI_CFG_FW_SPS,
863 };
864 
865 /**
866  * mei_me_dev_init - allocates and initializes the mei device structure
867  *
868  * @pdev: The pci device structure
869  * @cfg: per device generation config
870  *
871  * Return: The mei_device_device pointer on success, NULL on failure.
872  */
873 struct mei_device *mei_me_dev_init(struct pci_dev *pdev,
874 				   const struct mei_cfg *cfg)
875 {
876 	struct mei_device *dev;
877 	struct mei_me_hw *hw;
878 
879 	dev = kzalloc(sizeof(struct mei_device) +
880 			 sizeof(struct mei_me_hw), GFP_KERNEL);
881 	if (!dev)
882 		return NULL;
883 	hw = to_me_hw(dev);
884 
885 	mei_device_init(dev, &pdev->dev, &mei_me_hw_ops);
886 	hw->cfg = cfg;
887 	return dev;
888 }
889 
890