1 /*
2  * H/W layer of ISHTP provider device (ISH)
3  *
4  * Copyright (c) 2014-2016, 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 #include <linux/sched.h>
17 #include <linux/spinlock.h>
18 #include <linux/delay.h>
19 #include <linux/jiffies.h>
20 #include "client.h"
21 #include "hw-ish.h"
22 #include "hbm.h"
23 
24 /* For FW reset flow */
25 static struct work_struct fw_reset_work;
26 static struct ishtp_device *ishtp_dev;
27 
28 /**
29  * ish_reg_read() - Read register
30  * @dev: ISHTP device pointer
31  * @offset: Register offset
32  *
33  * Read 32 bit register at a given offset
34  *
35  * Return: Read register value
36  */
37 static inline uint32_t ish_reg_read(const struct ishtp_device *dev,
38 	unsigned long offset)
39 {
40 	struct ish_hw *hw = to_ish_hw(dev);
41 
42 	return readl(hw->mem_addr + offset);
43 }
44 
45 /**
46  * ish_reg_write() - Write register
47  * @dev: ISHTP device pointer
48  * @offset: Register offset
49  * @value: Value to write
50  *
51  * Writes 32 bit register at a give offset
52  */
53 static inline void ish_reg_write(struct ishtp_device *dev,
54 				 unsigned long offset,
55 				 uint32_t value)
56 {
57 	struct ish_hw *hw = to_ish_hw(dev);
58 
59 	writel(value, hw->mem_addr + offset);
60 }
61 
62 /**
63  * _ish_read_fw_sts_reg() - Read FW status register
64  * @dev: ISHTP device pointer
65  *
66  * Read FW status register
67  *
68  * Return: Read register value
69  */
70 static inline uint32_t _ish_read_fw_sts_reg(struct ishtp_device *dev)
71 {
72 	return ish_reg_read(dev, IPC_REG_ISH_HOST_FWSTS);
73 }
74 
75 /**
76  * check_generated_interrupt() - Check if ISH interrupt
77  * @dev: ISHTP device pointer
78  *
79  * Check if an interrupt was generated for ISH
80  *
81  * Return: Read true or false
82  */
83 static bool check_generated_interrupt(struct ishtp_device *dev)
84 {
85 	bool interrupt_generated = true;
86 	uint32_t pisr_val = 0;
87 
88 	if (dev->pdev->device == CHV_DEVICE_ID) {
89 		pisr_val = ish_reg_read(dev, IPC_REG_PISR_CHV_AB);
90 		interrupt_generated =
91 			IPC_INT_FROM_ISH_TO_HOST_CHV_AB(pisr_val);
92 	} else {
93 		pisr_val = ish_reg_read(dev, IPC_REG_PISR_BXT);
94 		interrupt_generated = IPC_INT_FROM_ISH_TO_HOST_BXT(pisr_val);
95 	}
96 
97 	return interrupt_generated;
98 }
99 
100 /**
101  * ish_is_input_ready() - Check if FW ready for RX
102  * @dev: ISHTP device pointer
103  *
104  * Check if ISH FW is ready for receiving data
105  *
106  * Return: Read true or false
107  */
108 static bool ish_is_input_ready(struct ishtp_device *dev)
109 {
110 	uint32_t doorbell_val;
111 
112 	doorbell_val = ish_reg_read(dev, IPC_REG_HOST2ISH_DRBL);
113 	return !IPC_IS_BUSY(doorbell_val);
114 }
115 
116 /**
117  * set_host_ready() - Indicate host ready
118  * @dev: ISHTP device pointer
119  *
120  * Set host ready indication to FW
121  */
122 static void set_host_ready(struct ishtp_device *dev)
123 {
124 	if (dev->pdev->device == CHV_DEVICE_ID) {
125 		if (dev->pdev->revision == REVISION_ID_CHT_A0 ||
126 				(dev->pdev->revision & REVISION_ID_SI_MASK) ==
127 				REVISION_ID_CHT_Ax_SI)
128 			ish_reg_write(dev, IPC_REG_HOST_COMM, 0x81);
129 		else if (dev->pdev->revision == REVISION_ID_CHT_B0 ||
130 				(dev->pdev->revision & REVISION_ID_SI_MASK) ==
131 				REVISION_ID_CHT_Bx_SI ||
132 				(dev->pdev->revision & REVISION_ID_SI_MASK) ==
133 				REVISION_ID_CHT_Kx_SI ||
134 				(dev->pdev->revision & REVISION_ID_SI_MASK) ==
135 				REVISION_ID_CHT_Dx_SI) {
136 			uint32_t host_comm_val;
137 
138 			host_comm_val = ish_reg_read(dev, IPC_REG_HOST_COMM);
139 			host_comm_val |= IPC_HOSTCOMM_INT_EN_BIT_CHV_AB | 0x81;
140 			ish_reg_write(dev, IPC_REG_HOST_COMM, host_comm_val);
141 		}
142 	} else {
143 			uint32_t host_pimr_val;
144 
145 			host_pimr_val = ish_reg_read(dev, IPC_REG_PIMR_BXT);
146 			host_pimr_val |= IPC_PIMR_INT_EN_BIT_BXT;
147 			/*
148 			 * disable interrupt generated instead of
149 			 * RX_complete_msg
150 			 */
151 			host_pimr_val &= ~IPC_HOST2ISH_BUSYCLEAR_MASK_BIT;
152 
153 			ish_reg_write(dev, IPC_REG_PIMR_BXT, host_pimr_val);
154 	}
155 }
156 
157 /**
158  * ishtp_fw_is_ready() - Check if FW ready
159  * @dev: ISHTP device pointer
160  *
161  * Check if ISH FW is ready
162  *
163  * Return: Read true or false
164  */
165 static bool ishtp_fw_is_ready(struct ishtp_device *dev)
166 {
167 	uint32_t ish_status = _ish_read_fw_sts_reg(dev);
168 
169 	return IPC_IS_ISH_ILUP(ish_status) &&
170 		IPC_IS_ISH_ISHTP_READY(ish_status);
171 }
172 
173 /**
174  * ish_set_host_rdy() - Indicate host ready
175  * @dev: ISHTP device pointer
176  *
177  * Set host ready indication to FW
178  */
179 static void ish_set_host_rdy(struct ishtp_device *dev)
180 {
181 	uint32_t host_status = ish_reg_read(dev, IPC_REG_HOST_COMM);
182 
183 	IPC_SET_HOST_READY(host_status);
184 	ish_reg_write(dev, IPC_REG_HOST_COMM, host_status);
185 }
186 
187 /**
188  * ish_clr_host_rdy() - Indicate host not ready
189  * @dev: ISHTP device pointer
190  *
191  * Send host not ready indication to FW
192  */
193 static void ish_clr_host_rdy(struct ishtp_device *dev)
194 {
195 	uint32_t host_status = ish_reg_read(dev, IPC_REG_HOST_COMM);
196 
197 	IPC_CLEAR_HOST_READY(host_status);
198 	ish_reg_write(dev, IPC_REG_HOST_COMM, host_status);
199 }
200 
201 /**
202  * _ishtp_read_hdr() - Read message header
203  * @dev: ISHTP device pointer
204  *
205  * Read header of 32bit length
206  *
207  * Return: Read register value
208  */
209 static uint32_t _ishtp_read_hdr(const struct ishtp_device *dev)
210 {
211 	return ish_reg_read(dev, IPC_REG_ISH2HOST_MSG);
212 }
213 
214 /**
215  * _ishtp_read - Read message
216  * @dev: ISHTP device pointer
217  * @buffer: message buffer
218  * @buffer_length: length of message buffer
219  *
220  * Read message from FW
221  *
222  * Return: Always 0
223  */
224 static int _ishtp_read(struct ishtp_device *dev, unsigned char *buffer,
225 	unsigned long buffer_length)
226 {
227 	uint32_t	i;
228 	uint32_t	*r_buf = (uint32_t *)buffer;
229 	uint32_t	msg_offs;
230 
231 	msg_offs = IPC_REG_ISH2HOST_MSG + sizeof(struct ishtp_msg_hdr);
232 	for (i = 0; i < buffer_length; i += sizeof(uint32_t))
233 		*r_buf++ = ish_reg_read(dev, msg_offs + i);
234 
235 	return 0;
236 }
237 
238 /**
239  * write_ipc_from_queue() - try to write ipc msg from Tx queue to device
240  * @dev: ishtp device pointer
241  *
242  * Check if DRBL is cleared. if it is - write the first IPC msg,  then call
243  * the callback function (unless it's NULL)
244  *
245  * Return: 0 for success else failure code
246  */
247 static int write_ipc_from_queue(struct ishtp_device *dev)
248 {
249 	struct wr_msg_ctl_info	*ipc_link;
250 	unsigned long	length;
251 	unsigned long	rem;
252 	unsigned long	flags;
253 	uint32_t	doorbell_val;
254 	uint32_t	*r_buf;
255 	uint32_t	reg_addr;
256 	int	i;
257 	void	(*ipc_send_compl)(void *);
258 	void	*ipc_send_compl_prm;
259 	static int	out_ipc_locked;
260 	unsigned long	out_ipc_flags;
261 
262 	if (dev->dev_state == ISHTP_DEV_DISABLED)
263 		return	-EINVAL;
264 
265 	spin_lock_irqsave(&dev->out_ipc_spinlock, out_ipc_flags);
266 	if (out_ipc_locked) {
267 		spin_unlock_irqrestore(&dev->out_ipc_spinlock, out_ipc_flags);
268 		return -EBUSY;
269 	}
270 	out_ipc_locked = 1;
271 	if (!ish_is_input_ready(dev)) {
272 		out_ipc_locked = 0;
273 		spin_unlock_irqrestore(&dev->out_ipc_spinlock, out_ipc_flags);
274 		return -EBUSY;
275 	}
276 	spin_unlock_irqrestore(&dev->out_ipc_spinlock, out_ipc_flags);
277 
278 	spin_lock_irqsave(&dev->wr_processing_spinlock, flags);
279 	/*
280 	 * if tx send list is empty - return 0;
281 	 * may happen, as RX_COMPLETE handler doesn't check list emptiness.
282 	 */
283 	if (list_empty(&dev->wr_processing_list_head.link)) {
284 		spin_unlock_irqrestore(&dev->wr_processing_spinlock, flags);
285 		out_ipc_locked = 0;
286 		return	0;
287 	}
288 
289 	ipc_link = list_entry(dev->wr_processing_list_head.link.next,
290 			      struct wr_msg_ctl_info, link);
291 	/* first 4 bytes of the data is the doorbell value (IPC header) */
292 	length = ipc_link->length - sizeof(uint32_t);
293 	doorbell_val = *(uint32_t *)ipc_link->inline_data;
294 	r_buf = (uint32_t *)(ipc_link->inline_data + sizeof(uint32_t));
295 
296 	/* If sending MNG_SYNC_FW_CLOCK, update clock again */
297 	if (IPC_HEADER_GET_PROTOCOL(doorbell_val) == IPC_PROTOCOL_MNG &&
298 		IPC_HEADER_GET_MNG_CMD(doorbell_val) == MNG_SYNC_FW_CLOCK) {
299 		uint64_t usec_system, usec_utc;
300 		struct ipc_time_update_msg time_update;
301 		struct time_sync_format ts_format;
302 
303 		usec_system = ktime_to_us(ktime_get_boottime());
304 		usec_utc = ktime_to_us(ktime_get_real());
305 		ts_format.ts1_source = HOST_SYSTEM_TIME_USEC;
306 		ts_format.ts2_source = HOST_UTC_TIME_USEC;
307 		ts_format.reserved = 0;
308 
309 		time_update.primary_host_time = usec_system;
310 		time_update.secondary_host_time = usec_utc;
311 		time_update.sync_info = ts_format;
312 
313 		memcpy(r_buf, &time_update,
314 		       sizeof(struct ipc_time_update_msg));
315 	}
316 
317 	for (i = 0, reg_addr = IPC_REG_HOST2ISH_MSG; i < length >> 2; i++,
318 			reg_addr += 4)
319 		ish_reg_write(dev, reg_addr, r_buf[i]);
320 
321 	rem = length & 0x3;
322 	if (rem > 0) {
323 		uint32_t reg = 0;
324 
325 		memcpy(&reg, &r_buf[length >> 2], rem);
326 		ish_reg_write(dev, reg_addr, reg);
327 	}
328 	/* Flush writes to msg registers and doorbell */
329 	ish_reg_read(dev, IPC_REG_ISH_HOST_FWSTS);
330 
331 	/* Update IPC counters */
332 	++dev->ipc_tx_cnt;
333 	dev->ipc_tx_bytes_cnt += IPC_HEADER_GET_LENGTH(doorbell_val);
334 
335 	ish_reg_write(dev, IPC_REG_HOST2ISH_DRBL, doorbell_val);
336 	out_ipc_locked = 0;
337 
338 	ipc_send_compl = ipc_link->ipc_send_compl;
339 	ipc_send_compl_prm = ipc_link->ipc_send_compl_prm;
340 	list_del_init(&ipc_link->link);
341 	list_add_tail(&ipc_link->link, &dev->wr_free_list_head.link);
342 	spin_unlock_irqrestore(&dev->wr_processing_spinlock, flags);
343 
344 	/*
345 	 * callback will be called out of spinlock,
346 	 * after ipc_link returned to free list
347 	 */
348 	if (ipc_send_compl)
349 		ipc_send_compl(ipc_send_compl_prm);
350 
351 	return 0;
352 }
353 
354 /**
355  * write_ipc_to_queue() - write ipc msg to Tx queue
356  * @dev: ishtp device instance
357  * @ipc_send_compl: Send complete callback
358  * @ipc_send_compl_prm:	Parameter to send in complete callback
359  * @msg: Pointer to message
360  * @length: Length of message
361  *
362  * Recived msg with IPC (and upper protocol) header  and add it to the device
363  *  Tx-to-write list then try to send the first IPC waiting msg
364  *  (if DRBL is cleared)
365  * This function returns negative value for failure (means free list
366  *  is empty, or msg too long) and 0 for success.
367  *
368  * Return: 0 for success else failure code
369  */
370 static int write_ipc_to_queue(struct ishtp_device *dev,
371 	void (*ipc_send_compl)(void *), void *ipc_send_compl_prm,
372 	unsigned char *msg, int length)
373 {
374 	struct wr_msg_ctl_info *ipc_link;
375 	unsigned long	flags;
376 
377 	if (length > IPC_FULL_MSG_SIZE)
378 		return -EMSGSIZE;
379 
380 	spin_lock_irqsave(&dev->wr_processing_spinlock, flags);
381 	if (list_empty(&dev->wr_free_list_head.link)) {
382 		spin_unlock_irqrestore(&dev->wr_processing_spinlock, flags);
383 		return -ENOMEM;
384 	}
385 	ipc_link = list_entry(dev->wr_free_list_head.link.next,
386 		struct wr_msg_ctl_info, link);
387 	list_del_init(&ipc_link->link);
388 
389 	ipc_link->ipc_send_compl = ipc_send_compl;
390 	ipc_link->ipc_send_compl_prm = ipc_send_compl_prm;
391 	ipc_link->length = length;
392 	memcpy(ipc_link->inline_data, msg, length);
393 
394 	list_add_tail(&ipc_link->link, &dev->wr_processing_list_head.link);
395 	spin_unlock_irqrestore(&dev->wr_processing_spinlock, flags);
396 
397 	write_ipc_from_queue(dev);
398 
399 	return 0;
400 }
401 
402 /**
403  * ipc_send_mng_msg() - Send management message
404  * @dev: ishtp device instance
405  * @msg_code: Message code
406  * @msg: Pointer to message
407  * @size: Length of message
408  *
409  * Send management message to FW
410  *
411  * Return: 0 for success else failure code
412  */
413 static int ipc_send_mng_msg(struct ishtp_device *dev, uint32_t msg_code,
414 	void *msg, size_t size)
415 {
416 	unsigned char	ipc_msg[IPC_FULL_MSG_SIZE];
417 	uint32_t	drbl_val = IPC_BUILD_MNG_MSG(msg_code, size);
418 
419 	memcpy(ipc_msg, &drbl_val, sizeof(uint32_t));
420 	memcpy(ipc_msg + sizeof(uint32_t), msg, size);
421 	return	write_ipc_to_queue(dev, NULL, NULL, ipc_msg,
422 		sizeof(uint32_t) + size);
423 }
424 
425 #define WAIT_FOR_FW_RDY			0x1
426 #define WAIT_FOR_INPUT_RDY		0x2
427 
428 /**
429  * timed_wait_for_timeout() - wait special event with timeout
430  * @dev: ISHTP device pointer
431  * @condition: indicate the condition for waiting
432  * @timeinc: time slice for every wait cycle, in ms
433  * @timeout: time in ms for timeout
434  *
435  * This function will check special event to be ready in a loop, the loop
436  * period is specificd in timeinc. Wait timeout will causes failure.
437  *
438  * Return: 0 for success else failure code
439  */
440 static int timed_wait_for_timeout(struct ishtp_device *dev, int condition,
441 				unsigned int timeinc, unsigned int timeout)
442 {
443 	bool complete = false;
444 	int ret;
445 
446 	do {
447 		if (condition == WAIT_FOR_FW_RDY) {
448 			complete = ishtp_fw_is_ready(dev);
449 		} else if (condition == WAIT_FOR_INPUT_RDY) {
450 			complete = ish_is_input_ready(dev);
451 		} else {
452 			ret = -EINVAL;
453 			goto out;
454 		}
455 
456 		if (!complete) {
457 			unsigned long left_time;
458 
459 			left_time = msleep_interruptible(timeinc);
460 			timeout -= (timeinc - left_time);
461 		}
462 	} while (!complete && timeout > 0);
463 
464 	if (complete)
465 		ret = 0;
466 	else
467 		ret = -EBUSY;
468 
469 out:
470 	return ret;
471 }
472 
473 #define TIME_SLICE_FOR_FW_RDY_MS		100
474 #define TIME_SLICE_FOR_INPUT_RDY_MS		100
475 #define TIMEOUT_FOR_FW_RDY_MS			2000
476 #define TIMEOUT_FOR_INPUT_RDY_MS		2000
477 
478 /**
479  * ish_fw_reset_handler() - FW reset handler
480  * @dev: ishtp device pointer
481  *
482  * Handle FW reset
483  *
484  * Return: 0 for success else failure code
485  */
486 static int ish_fw_reset_handler(struct ishtp_device *dev)
487 {
488 	uint32_t	reset_id;
489 	unsigned long	flags;
490 	struct wr_msg_ctl_info *processing, *next;
491 
492 	/* Read reset ID */
493 	reset_id = ish_reg_read(dev, IPC_REG_ISH2HOST_MSG) & 0xFFFF;
494 
495 	/* Clear IPC output queue */
496 	spin_lock_irqsave(&dev->wr_processing_spinlock, flags);
497 	list_for_each_entry_safe(processing, next,
498 			&dev->wr_processing_list_head.link, link) {
499 		list_move_tail(&processing->link, &dev->wr_free_list_head.link);
500 	}
501 	spin_unlock_irqrestore(&dev->wr_processing_spinlock, flags);
502 
503 	/* ISHTP notification in IPC_RESET */
504 	ishtp_reset_handler(dev);
505 
506 	if (!ish_is_input_ready(dev))
507 		timed_wait_for_timeout(dev, WAIT_FOR_INPUT_RDY,
508 			TIME_SLICE_FOR_INPUT_RDY_MS, TIMEOUT_FOR_INPUT_RDY_MS);
509 
510 	/* ISH FW is dead */
511 	if (!ish_is_input_ready(dev))
512 		return	-EPIPE;
513 	/*
514 	 * Set HOST2ISH.ILUP. Apparently we need this BEFORE sending
515 	 * RESET_NOTIFY_ACK - FW will be checking for it
516 	 */
517 	ish_set_host_rdy(dev);
518 	/* Send RESET_NOTIFY_ACK (with reset_id) */
519 	ipc_send_mng_msg(dev, MNG_RESET_NOTIFY_ACK, &reset_id,
520 			 sizeof(uint32_t));
521 
522 	/* Wait for ISH FW'es ILUP and ISHTP_READY */
523 	timed_wait_for_timeout(dev, WAIT_FOR_FW_RDY,
524 			TIME_SLICE_FOR_FW_RDY_MS, TIMEOUT_FOR_FW_RDY_MS);
525 	if (!ishtp_fw_is_ready(dev)) {
526 		/* ISH FW is dead */
527 		uint32_t	ish_status;
528 
529 		ish_status = _ish_read_fw_sts_reg(dev);
530 		dev_err(dev->devc,
531 			"[ishtp-ish]: completed reset, ISH is dead (FWSTS = %08X)\n",
532 			ish_status);
533 		return -ENODEV;
534 	}
535 	return	0;
536 }
537 
538 #define TIMEOUT_FOR_HW_RDY_MS			300
539 
540 /**
541  * ish_fw_reset_work_fn() - FW reset worker function
542  * @unused: not used
543  *
544  * Call ish_fw_reset_handler to complete FW reset
545  */
546 static void fw_reset_work_fn(struct work_struct *unused)
547 {
548 	int	rv;
549 
550 	rv = ish_fw_reset_handler(ishtp_dev);
551 	if (!rv) {
552 		/* ISH is ILUP & ISHTP-ready. Restart ISHTP */
553 		msleep_interruptible(TIMEOUT_FOR_HW_RDY_MS);
554 		ishtp_dev->recvd_hw_ready = 1;
555 		wake_up_interruptible(&ishtp_dev->wait_hw_ready);
556 
557 		/* ISHTP notification in IPC_RESET sequence completion */
558 		ishtp_reset_compl_handler(ishtp_dev);
559 	} else
560 		dev_err(ishtp_dev->devc, "[ishtp-ish]: FW reset failed (%d)\n",
561 			rv);
562 }
563 
564 /**
565  * _ish_sync_fw_clock() -Sync FW clock with the OS clock
566  * @dev: ishtp device pointer
567  *
568  * Sync FW and OS time
569  */
570 static void _ish_sync_fw_clock(struct ishtp_device *dev)
571 {
572 	static unsigned long	prev_sync;
573 	uint64_t	usec;
574 
575 	if (prev_sync && jiffies - prev_sync < 20 * HZ)
576 		return;
577 
578 	prev_sync = jiffies;
579 	usec = ktime_to_us(ktime_get_boottime());
580 	ipc_send_mng_msg(dev, MNG_SYNC_FW_CLOCK, &usec, sizeof(uint64_t));
581 }
582 
583 /**
584  * recv_ipc() - Receive and process IPC management messages
585  * @dev: ishtp device instance
586  * @doorbell_val: doorbell value
587  *
588  * This function runs in ISR context.
589  * NOTE: Any other mng command than reset_notify and reset_notify_ack
590  * won't wake BH handler
591  */
592 static void	recv_ipc(struct ishtp_device *dev, uint32_t doorbell_val)
593 {
594 	uint32_t	mng_cmd;
595 
596 	mng_cmd = IPC_HEADER_GET_MNG_CMD(doorbell_val);
597 
598 	switch (mng_cmd) {
599 	default:
600 		break;
601 
602 	case MNG_RX_CMPL_INDICATION:
603 		if (dev->suspend_flag) {
604 			dev->suspend_flag = 0;
605 			wake_up_interruptible(&dev->suspend_wait);
606 		}
607 		if (dev->resume_flag) {
608 			dev->resume_flag = 0;
609 			wake_up_interruptible(&dev->resume_wait);
610 		}
611 
612 		write_ipc_from_queue(dev);
613 		break;
614 
615 	case MNG_RESET_NOTIFY:
616 		if (!ishtp_dev) {
617 			ishtp_dev = dev;
618 			INIT_WORK(&fw_reset_work, fw_reset_work_fn);
619 		}
620 		schedule_work(&fw_reset_work);
621 		break;
622 
623 	case MNG_RESET_NOTIFY_ACK:
624 		dev->recvd_hw_ready = 1;
625 		wake_up_interruptible(&dev->wait_hw_ready);
626 		break;
627 	}
628 }
629 
630 /**
631  * ish_irq_handler() - ISH IRQ handler
632  * @irq: irq number
633  * @dev_id: ishtp device pointer
634  *
635  * ISH IRQ handler. If interrupt is generated and is for ISH it will process
636  * the interrupt.
637  */
638 irqreturn_t ish_irq_handler(int irq, void *dev_id)
639 {
640 	struct ishtp_device	*dev = dev_id;
641 	uint32_t	doorbell_val;
642 	bool	interrupt_generated;
643 
644 	/* Check that it's interrupt from ISH (may be shared) */
645 	interrupt_generated = check_generated_interrupt(dev);
646 
647 	if (!interrupt_generated)
648 		return IRQ_NONE;
649 
650 	doorbell_val = ish_reg_read(dev, IPC_REG_ISH2HOST_DRBL);
651 	if (!IPC_IS_BUSY(doorbell_val))
652 		return IRQ_HANDLED;
653 
654 	if (dev->dev_state == ISHTP_DEV_DISABLED)
655 		return	IRQ_HANDLED;
656 
657 	/* Sanity check: IPC dgram length in header */
658 	if (IPC_HEADER_GET_LENGTH(doorbell_val) > IPC_PAYLOAD_SIZE) {
659 		dev_err(dev->devc,
660 			"IPC hdr - bad length: %u; dropped\n",
661 			(unsigned int)IPC_HEADER_GET_LENGTH(doorbell_val));
662 		goto	eoi;
663 	}
664 
665 	switch (IPC_HEADER_GET_PROTOCOL(doorbell_val)) {
666 	default:
667 		break;
668 	case IPC_PROTOCOL_MNG:
669 		recv_ipc(dev, doorbell_val);
670 		break;
671 	case IPC_PROTOCOL_ISHTP:
672 		ishtp_recv(dev);
673 		break;
674 	}
675 
676 eoi:
677 	/* Update IPC counters */
678 	++dev->ipc_rx_cnt;
679 	dev->ipc_rx_bytes_cnt += IPC_HEADER_GET_LENGTH(doorbell_val);
680 
681 	ish_reg_write(dev, IPC_REG_ISH2HOST_DRBL, 0);
682 	/* Flush write to doorbell */
683 	ish_reg_read(dev, IPC_REG_ISH_HOST_FWSTS);
684 
685 	return	IRQ_HANDLED;
686 }
687 
688 /**
689  * ish_disable_dma() - disable dma communication between host and ISHFW
690  * @dev: ishtp device pointer
691  *
692  * Clear the dma enable bit and wait for dma inactive.
693  *
694  * Return: 0 for success else error code.
695  */
696 static int ish_disable_dma(struct ishtp_device *dev)
697 {
698 	unsigned int	dma_delay;
699 
700 	/* Clear the dma enable bit */
701 	ish_reg_write(dev, IPC_REG_ISH_RMP2, 0);
702 
703 	/* wait for dma inactive */
704 	for (dma_delay = 0; dma_delay < MAX_DMA_DELAY &&
705 		_ish_read_fw_sts_reg(dev) & (IPC_ISH_IN_DMA);
706 		dma_delay += 5)
707 		mdelay(5);
708 
709 	if (dma_delay >= MAX_DMA_DELAY) {
710 		dev_err(dev->devc,
711 			"Wait for DMA inactive timeout\n");
712 		return	-EBUSY;
713 	}
714 
715 	return 0;
716 }
717 
718 /**
719  * ish_wakeup() - wakeup ishfw from waiting-for-host state
720  * @dev: ishtp device pointer
721  *
722  * Set the dma enable bit and send a void message to FW,
723  * it wil wakeup FW from waiting-for-host state.
724  */
725 static void ish_wakeup(struct ishtp_device *dev)
726 {
727 	/* Set dma enable bit */
728 	ish_reg_write(dev, IPC_REG_ISH_RMP2, IPC_RMP2_DMA_ENABLED);
729 
730 	/*
731 	 * Send 0 IPC message so that ISH FW wakes up if it was already
732 	 * asleep.
733 	 */
734 	ish_reg_write(dev, IPC_REG_HOST2ISH_DRBL, IPC_DRBL_BUSY_BIT);
735 
736 	/* Flush writes to doorbell and REMAP2 */
737 	ish_reg_read(dev, IPC_REG_ISH_HOST_FWSTS);
738 }
739 
740 /**
741  * _ish_hw_reset() - HW reset
742  * @dev: ishtp device pointer
743  *
744  * Reset ISH HW to recover if any error
745  *
746  * Return: 0 for success else error fault code
747  */
748 static int _ish_hw_reset(struct ishtp_device *dev)
749 {
750 	struct pci_dev *pdev = dev->pdev;
751 	int	rv;
752 	uint16_t csr;
753 
754 	if (!pdev)
755 		return	-ENODEV;
756 
757 	rv = pci_reset_function(pdev);
758 	if (!rv)
759 		dev->dev_state = ISHTP_DEV_RESETTING;
760 
761 	if (!pdev->pm_cap) {
762 		dev_err(&pdev->dev, "Can't reset - no PM caps\n");
763 		return	-EINVAL;
764 	}
765 
766 	/* Disable dma communication between FW and host */
767 	if (ish_disable_dma(dev)) {
768 		dev_err(&pdev->dev,
769 			"Can't reset - stuck with DMA in-progress\n");
770 		return	-EBUSY;
771 	}
772 
773 	pci_read_config_word(pdev, pdev->pm_cap + PCI_PM_CTRL, &csr);
774 
775 	csr &= ~PCI_PM_CTRL_STATE_MASK;
776 	csr |= PCI_D3hot;
777 	pci_write_config_word(pdev, pdev->pm_cap + PCI_PM_CTRL, csr);
778 
779 	mdelay(pdev->d3_delay);
780 
781 	csr &= ~PCI_PM_CTRL_STATE_MASK;
782 	csr |= PCI_D0;
783 	pci_write_config_word(pdev, pdev->pm_cap + PCI_PM_CTRL, csr);
784 
785 	/* Now we can enable ISH DMA operation and wakeup ISHFW */
786 	ish_wakeup(dev);
787 
788 	return	0;
789 }
790 
791 /**
792  * _ish_ipc_reset() - IPC reset
793  * @dev: ishtp device pointer
794  *
795  * Resets host and fw IPC and upper layers
796  *
797  * Return: 0 for success else error fault code
798  */
799 static int _ish_ipc_reset(struct ishtp_device *dev)
800 {
801 	struct ipc_rst_payload_type ipc_mng_msg;
802 	int	rv = 0;
803 
804 	ipc_mng_msg.reset_id = 1;
805 	ipc_mng_msg.reserved = 0;
806 
807 	set_host_ready(dev);
808 
809 	/* Clear the incoming doorbell */
810 	ish_reg_write(dev, IPC_REG_ISH2HOST_DRBL, 0);
811 	/* Flush write to doorbell */
812 	ish_reg_read(dev, IPC_REG_ISH_HOST_FWSTS);
813 
814 	dev->recvd_hw_ready = 0;
815 
816 	/* send message */
817 	rv = ipc_send_mng_msg(dev, MNG_RESET_NOTIFY, &ipc_mng_msg,
818 		sizeof(struct ipc_rst_payload_type));
819 	if (rv) {
820 		dev_err(dev->devc, "Failed to send IPC MNG_RESET_NOTIFY\n");
821 		return	rv;
822 	}
823 
824 	wait_event_interruptible_timeout(dev->wait_hw_ready,
825 					 dev->recvd_hw_ready, 2 * HZ);
826 	if (!dev->recvd_hw_ready) {
827 		dev_err(dev->devc, "Timed out waiting for HW ready\n");
828 		rv = -ENODEV;
829 	}
830 
831 	return rv;
832 }
833 
834 /**
835  * ish_hw_start() -Start ISH HW
836  * @dev: ishtp device pointer
837  *
838  * Set host to ready state and wait for FW reset
839  *
840  * Return: 0 for success else error fault code
841  */
842 int ish_hw_start(struct ishtp_device *dev)
843 {
844 	ish_set_host_rdy(dev);
845 
846 	/* After that we can enable ISH DMA operation and wakeup ISHFW */
847 	ish_wakeup(dev);
848 
849 	set_host_ready(dev);
850 
851 	/* wait for FW-initiated reset flow */
852 	if (!dev->recvd_hw_ready)
853 		wait_event_interruptible_timeout(dev->wait_hw_ready,
854 						 dev->recvd_hw_ready,
855 						 10 * HZ);
856 
857 	if (!dev->recvd_hw_ready) {
858 		dev_err(dev->devc,
859 			"[ishtp-ish]: Timed out waiting for FW-initiated reset\n");
860 		return	-ENODEV;
861 	}
862 
863 	return 0;
864 }
865 
866 /**
867  * ish_ipc_get_header() -Get doorbell value
868  * @dev: ishtp device pointer
869  * @length: length of message
870  * @busy: busy status
871  *
872  * Get door bell value from message header
873  *
874  * Return: door bell value
875  */
876 static uint32_t ish_ipc_get_header(struct ishtp_device *dev, int length,
877 				   int busy)
878 {
879 	uint32_t drbl_val;
880 
881 	drbl_val = IPC_BUILD_HEADER(length, IPC_PROTOCOL_ISHTP, busy);
882 
883 	return drbl_val;
884 }
885 
886 static const struct ishtp_hw_ops ish_hw_ops = {
887 	.hw_reset = _ish_hw_reset,
888 	.ipc_reset = _ish_ipc_reset,
889 	.ipc_get_header = ish_ipc_get_header,
890 	.ishtp_read = _ishtp_read,
891 	.write = write_ipc_to_queue,
892 	.get_fw_status = _ish_read_fw_sts_reg,
893 	.sync_fw_clock = _ish_sync_fw_clock,
894 	.ishtp_read_hdr = _ishtp_read_hdr
895 };
896 
897 /**
898  * ish_dev_init() -Initialize ISH devoce
899  * @pdev: PCI device
900  *
901  * Allocate ISHTP device and initialize IPC processing
902  *
903  * Return: ISHTP device instance on success else NULL
904  */
905 struct ishtp_device *ish_dev_init(struct pci_dev *pdev)
906 {
907 	struct ishtp_device *dev;
908 	int	i;
909 
910 	dev = devm_kzalloc(&pdev->dev,
911 			   sizeof(struct ishtp_device) + sizeof(struct ish_hw),
912 			   GFP_KERNEL);
913 	if (!dev)
914 		return NULL;
915 
916 	ishtp_device_init(dev);
917 
918 	init_waitqueue_head(&dev->wait_hw_ready);
919 
920 	spin_lock_init(&dev->wr_processing_spinlock);
921 	spin_lock_init(&dev->out_ipc_spinlock);
922 
923 	/* Init IPC processing and free lists */
924 	INIT_LIST_HEAD(&dev->wr_processing_list_head.link);
925 	INIT_LIST_HEAD(&dev->wr_free_list_head.link);
926 	for (i = 0; i < IPC_TX_FIFO_SIZE; ++i) {
927 		struct wr_msg_ctl_info	*tx_buf;
928 
929 		tx_buf = devm_kzalloc(&pdev->dev,
930 				      sizeof(struct wr_msg_ctl_info),
931 				      GFP_KERNEL);
932 		if (!tx_buf) {
933 			/*
934 			 * IPC buffers may be limited or not available
935 			 * at all - although this shouldn't happen
936 			 */
937 			dev_err(dev->devc,
938 				"[ishtp-ish]: failure in Tx FIFO allocations (%d)\n",
939 				i);
940 			break;
941 		}
942 		list_add_tail(&tx_buf->link, &dev->wr_free_list_head.link);
943 	}
944 
945 	dev->ops = &ish_hw_ops;
946 	dev->devc = &pdev->dev;
947 	dev->mtu = IPC_PAYLOAD_SIZE - sizeof(struct ishtp_msg_hdr);
948 	return dev;
949 }
950 
951 /**
952  * ish_device_disable() - Disable ISH device
953  * @dev: ISHTP device pointer
954  *
955  * Disable ISH by clearing host ready to inform firmware.
956  */
957 void	ish_device_disable(struct ishtp_device *dev)
958 {
959 	struct pci_dev *pdev = dev->pdev;
960 
961 	if (!pdev)
962 		return;
963 
964 	/* Disable dma communication between FW and host */
965 	if (ish_disable_dma(dev)) {
966 		dev_err(&pdev->dev,
967 			"Can't reset - stuck with DMA in-progress\n");
968 		return;
969 	}
970 
971 	/* Put ISH to D3hot state for power saving */
972 	pci_set_power_state(pdev, PCI_D3hot);
973 
974 	dev->dev_state = ISHTP_DEV_DISABLED;
975 	ish_clr_host_rdy(dev);
976 }
977