1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * H/W layer of ISHTP provider device (ISH)
4  *
5  * Copyright (c) 2014-2016, Intel Corporation.
6  */
7 
8 #include <linux/sched.h>
9 #include <linux/spinlock.h>
10 #include <linux/delay.h>
11 #include <linux/jiffies.h>
12 #include "client.h"
13 #include "hw-ish.h"
14 #include "hbm.h"
15 
16 /* For FW reset flow */
17 static struct work_struct fw_reset_work;
18 static struct ishtp_device *ishtp_dev;
19 
20 /**
21  * ish_reg_read() - Read register
22  * @dev: ISHTP device pointer
23  * @offset: Register offset
24  *
25  * Read 32 bit register at a given offset
26  *
27  * Return: Read register value
28  */
29 static inline uint32_t ish_reg_read(const struct ishtp_device *dev,
30 	unsigned long offset)
31 {
32 	struct ish_hw *hw = to_ish_hw(dev);
33 
34 	return readl(hw->mem_addr + offset);
35 }
36 
37 /**
38  * ish_reg_write() - Write register
39  * @dev: ISHTP device pointer
40  * @offset: Register offset
41  * @value: Value to write
42  *
43  * Writes 32 bit register at a give offset
44  */
45 static inline void ish_reg_write(struct ishtp_device *dev,
46 				 unsigned long offset,
47 				 uint32_t value)
48 {
49 	struct ish_hw *hw = to_ish_hw(dev);
50 
51 	writel(value, hw->mem_addr + offset);
52 }
53 
54 /**
55  * _ish_read_fw_sts_reg() - Read FW status register
56  * @dev: ISHTP device pointer
57  *
58  * Read FW status register
59  *
60  * Return: Read register value
61  */
62 static inline uint32_t _ish_read_fw_sts_reg(struct ishtp_device *dev)
63 {
64 	return ish_reg_read(dev, IPC_REG_ISH_HOST_FWSTS);
65 }
66 
67 /**
68  * check_generated_interrupt() - Check if ISH interrupt
69  * @dev: ISHTP device pointer
70  *
71  * Check if an interrupt was generated for ISH
72  *
73  * Return: Read true or false
74  */
75 static bool check_generated_interrupt(struct ishtp_device *dev)
76 {
77 	bool interrupt_generated = true;
78 	uint32_t pisr_val = 0;
79 
80 	if (dev->pdev->device == CHV_DEVICE_ID) {
81 		pisr_val = ish_reg_read(dev, IPC_REG_PISR_CHV_AB);
82 		interrupt_generated =
83 			IPC_INT_FROM_ISH_TO_HOST_CHV_AB(pisr_val);
84 	} else {
85 		pisr_val = ish_reg_read(dev, IPC_REG_PISR_BXT);
86 		interrupt_generated = !!pisr_val;
87 		/* only busy-clear bit is RW, others are RO */
88 		if (pisr_val)
89 			ish_reg_write(dev, IPC_REG_PISR_BXT, pisr_val);
90 	}
91 
92 	return interrupt_generated;
93 }
94 
95 /**
96  * ish_is_input_ready() - Check if FW ready for RX
97  * @dev: ISHTP device pointer
98  *
99  * Check if ISH FW is ready for receiving data
100  *
101  * Return: Read true or false
102  */
103 static bool ish_is_input_ready(struct ishtp_device *dev)
104 {
105 	uint32_t doorbell_val;
106 
107 	doorbell_val = ish_reg_read(dev, IPC_REG_HOST2ISH_DRBL);
108 	return !IPC_IS_BUSY(doorbell_val);
109 }
110 
111 /**
112  * set_host_ready() - Indicate host ready
113  * @dev: ISHTP device pointer
114  *
115  * Set host ready indication to FW
116  */
117 static void set_host_ready(struct ishtp_device *dev)
118 {
119 	if (dev->pdev->device == CHV_DEVICE_ID) {
120 		if (dev->pdev->revision == REVISION_ID_CHT_A0 ||
121 				(dev->pdev->revision & REVISION_ID_SI_MASK) ==
122 				REVISION_ID_CHT_Ax_SI)
123 			ish_reg_write(dev, IPC_REG_HOST_COMM, 0x81);
124 		else if (dev->pdev->revision == REVISION_ID_CHT_B0 ||
125 				(dev->pdev->revision & REVISION_ID_SI_MASK) ==
126 				REVISION_ID_CHT_Bx_SI ||
127 				(dev->pdev->revision & REVISION_ID_SI_MASK) ==
128 				REVISION_ID_CHT_Kx_SI ||
129 				(dev->pdev->revision & REVISION_ID_SI_MASK) ==
130 				REVISION_ID_CHT_Dx_SI) {
131 			uint32_t host_comm_val;
132 
133 			host_comm_val = ish_reg_read(dev, IPC_REG_HOST_COMM);
134 			host_comm_val |= IPC_HOSTCOMM_INT_EN_BIT_CHV_AB | 0x81;
135 			ish_reg_write(dev, IPC_REG_HOST_COMM, host_comm_val);
136 		}
137 	} else {
138 			uint32_t host_pimr_val;
139 
140 			host_pimr_val = ish_reg_read(dev, IPC_REG_PIMR_BXT);
141 			host_pimr_val |= IPC_PIMR_INT_EN_BIT_BXT;
142 			/*
143 			 * disable interrupt generated instead of
144 			 * RX_complete_msg
145 			 */
146 			host_pimr_val &= ~IPC_HOST2ISH_BUSYCLEAR_MASK_BIT;
147 
148 			ish_reg_write(dev, IPC_REG_PIMR_BXT, host_pimr_val);
149 	}
150 }
151 
152 /**
153  * ishtp_fw_is_ready() - Check if FW ready
154  * @dev: ISHTP device pointer
155  *
156  * Check if ISH FW is ready
157  *
158  * Return: Read true or false
159  */
160 static bool ishtp_fw_is_ready(struct ishtp_device *dev)
161 {
162 	uint32_t ish_status = _ish_read_fw_sts_reg(dev);
163 
164 	return IPC_IS_ISH_ILUP(ish_status) &&
165 		IPC_IS_ISH_ISHTP_READY(ish_status);
166 }
167 
168 /**
169  * ish_set_host_rdy() - Indicate host ready
170  * @dev: ISHTP device pointer
171  *
172  * Set host ready indication to FW
173  */
174 static void ish_set_host_rdy(struct ishtp_device *dev)
175 {
176 	uint32_t host_status = ish_reg_read(dev, IPC_REG_HOST_COMM);
177 
178 	IPC_SET_HOST_READY(host_status);
179 	ish_reg_write(dev, IPC_REG_HOST_COMM, host_status);
180 }
181 
182 /**
183  * ish_clr_host_rdy() - Indicate host not ready
184  * @dev: ISHTP device pointer
185  *
186  * Send host not ready indication to FW
187  */
188 static void ish_clr_host_rdy(struct ishtp_device *dev)
189 {
190 	uint32_t host_status = ish_reg_read(dev, IPC_REG_HOST_COMM);
191 
192 	IPC_CLEAR_HOST_READY(host_status);
193 	ish_reg_write(dev, IPC_REG_HOST_COMM, host_status);
194 }
195 
196 static bool ish_chk_host_rdy(struct ishtp_device *dev)
197 {
198 	uint32_t host_status = ish_reg_read(dev, IPC_REG_HOST_COMM);
199 
200 	return (host_status & IPC_HOSTCOMM_READY_BIT);
201 }
202 
203 /**
204  * ish_set_host_ready() - reconfig ipc host registers
205  * @dev: ishtp device pointer
206  *
207  * Set host to ready state
208  * This API is called in some case:
209  *    fw is still on, but ipc is powered down.
210  *    such as OOB case.
211  *
212  * Return: 0 for success else error fault code
213  */
214 void ish_set_host_ready(struct ishtp_device *dev)
215 {
216 	if (ish_chk_host_rdy(dev))
217 		return;
218 
219 	ish_set_host_rdy(dev);
220 	set_host_ready(dev);
221 }
222 
223 /**
224  * _ishtp_read_hdr() - Read message header
225  * @dev: ISHTP device pointer
226  *
227  * Read header of 32bit length
228  *
229  * Return: Read register value
230  */
231 static uint32_t _ishtp_read_hdr(const struct ishtp_device *dev)
232 {
233 	return ish_reg_read(dev, IPC_REG_ISH2HOST_MSG);
234 }
235 
236 /**
237  * _ishtp_read - Read message
238  * @dev: ISHTP device pointer
239  * @buffer: message buffer
240  * @buffer_length: length of message buffer
241  *
242  * Read message from FW
243  *
244  * Return: Always 0
245  */
246 static int _ishtp_read(struct ishtp_device *dev, unsigned char *buffer,
247 	unsigned long buffer_length)
248 {
249 	uint32_t	i;
250 	uint32_t	*r_buf = (uint32_t *)buffer;
251 	uint32_t	msg_offs;
252 
253 	msg_offs = IPC_REG_ISH2HOST_MSG + sizeof(struct ishtp_msg_hdr);
254 	for (i = 0; i < buffer_length; i += sizeof(uint32_t))
255 		*r_buf++ = ish_reg_read(dev, msg_offs + i);
256 
257 	return 0;
258 }
259 
260 /**
261  * write_ipc_from_queue() - try to write ipc msg from Tx queue to device
262  * @dev: ishtp device pointer
263  *
264  * Check if DRBL is cleared. if it is - write the first IPC msg,  then call
265  * the callback function (unless it's NULL)
266  *
267  * Return: 0 for success else failure code
268  */
269 static int write_ipc_from_queue(struct ishtp_device *dev)
270 {
271 	struct wr_msg_ctl_info	*ipc_link;
272 	unsigned long	length;
273 	unsigned long	rem;
274 	unsigned long	flags;
275 	uint32_t	doorbell_val;
276 	uint32_t	*r_buf;
277 	uint32_t	reg_addr;
278 	int	i;
279 	void	(*ipc_send_compl)(void *);
280 	void	*ipc_send_compl_prm;
281 
282 	if (dev->dev_state == ISHTP_DEV_DISABLED)
283 		return -EINVAL;
284 
285 	spin_lock_irqsave(&dev->wr_processing_spinlock, flags);
286 	if (!ish_is_input_ready(dev)) {
287 		spin_unlock_irqrestore(&dev->wr_processing_spinlock, flags);
288 		return -EBUSY;
289 	}
290 
291 	/*
292 	 * if tx send list is empty - return 0;
293 	 * may happen, as RX_COMPLETE handler doesn't check list emptiness.
294 	 */
295 	if (list_empty(&dev->wr_processing_list)) {
296 		spin_unlock_irqrestore(&dev->wr_processing_spinlock, flags);
297 		return	0;
298 	}
299 
300 	ipc_link = list_first_entry(&dev->wr_processing_list,
301 				    struct wr_msg_ctl_info, link);
302 	/* first 4 bytes of the data is the doorbell value (IPC header) */
303 	length = ipc_link->length - sizeof(uint32_t);
304 	doorbell_val = *(uint32_t *)ipc_link->inline_data;
305 	r_buf = (uint32_t *)(ipc_link->inline_data + sizeof(uint32_t));
306 
307 	/* If sending MNG_SYNC_FW_CLOCK, update clock again */
308 	if (IPC_HEADER_GET_PROTOCOL(doorbell_val) == IPC_PROTOCOL_MNG &&
309 		IPC_HEADER_GET_MNG_CMD(doorbell_val) == MNG_SYNC_FW_CLOCK) {
310 		uint64_t usec_system, usec_utc;
311 		struct ipc_time_update_msg time_update;
312 		struct time_sync_format ts_format;
313 
314 		usec_system = ktime_to_us(ktime_get_boottime());
315 		usec_utc = ktime_to_us(ktime_get_real());
316 		ts_format.ts1_source = HOST_SYSTEM_TIME_USEC;
317 		ts_format.ts2_source = HOST_UTC_TIME_USEC;
318 		ts_format.reserved = 0;
319 
320 		time_update.primary_host_time = usec_system;
321 		time_update.secondary_host_time = usec_utc;
322 		time_update.sync_info = ts_format;
323 
324 		memcpy(r_buf, &time_update,
325 		       sizeof(struct ipc_time_update_msg));
326 	}
327 
328 	for (i = 0, reg_addr = IPC_REG_HOST2ISH_MSG; i < length >> 2; i++,
329 			reg_addr += 4)
330 		ish_reg_write(dev, reg_addr, r_buf[i]);
331 
332 	rem = length & 0x3;
333 	if (rem > 0) {
334 		uint32_t reg = 0;
335 
336 		memcpy(&reg, &r_buf[length >> 2], rem);
337 		ish_reg_write(dev, reg_addr, reg);
338 	}
339 	ish_reg_write(dev, IPC_REG_HOST2ISH_DRBL, doorbell_val);
340 
341 	/* Flush writes to msg registers and doorbell */
342 	ish_reg_read(dev, IPC_REG_ISH_HOST_FWSTS);
343 
344 	/* Update IPC counters */
345 	++dev->ipc_tx_cnt;
346 	dev->ipc_tx_bytes_cnt += IPC_HEADER_GET_LENGTH(doorbell_val);
347 
348 	ipc_send_compl = ipc_link->ipc_send_compl;
349 	ipc_send_compl_prm = ipc_link->ipc_send_compl_prm;
350 	list_del_init(&ipc_link->link);
351 	list_add(&ipc_link->link, &dev->wr_free_list);
352 	spin_unlock_irqrestore(&dev->wr_processing_spinlock, flags);
353 
354 	/*
355 	 * callback will be called out of spinlock,
356 	 * after ipc_link returned to free list
357 	 */
358 	if (ipc_send_compl)
359 		ipc_send_compl(ipc_send_compl_prm);
360 
361 	return 0;
362 }
363 
364 /**
365  * write_ipc_to_queue() - write ipc msg to Tx queue
366  * @dev: ishtp device instance
367  * @ipc_send_compl: Send complete callback
368  * @ipc_send_compl_prm:	Parameter to send in complete callback
369  * @msg: Pointer to message
370  * @length: Length of message
371  *
372  * Recived msg with IPC (and upper protocol) header  and add it to the device
373  *  Tx-to-write list then try to send the first IPC waiting msg
374  *  (if DRBL is cleared)
375  * This function returns negative value for failure (means free list
376  *  is empty, or msg too long) and 0 for success.
377  *
378  * Return: 0 for success else failure code
379  */
380 static int write_ipc_to_queue(struct ishtp_device *dev,
381 	void (*ipc_send_compl)(void *), void *ipc_send_compl_prm,
382 	unsigned char *msg, int length)
383 {
384 	struct wr_msg_ctl_info *ipc_link;
385 	unsigned long flags;
386 
387 	if (length > IPC_FULL_MSG_SIZE)
388 		return -EMSGSIZE;
389 
390 	spin_lock_irqsave(&dev->wr_processing_spinlock, flags);
391 	if (list_empty(&dev->wr_free_list)) {
392 		spin_unlock_irqrestore(&dev->wr_processing_spinlock, flags);
393 		return -ENOMEM;
394 	}
395 	ipc_link = list_first_entry(&dev->wr_free_list,
396 				    struct wr_msg_ctl_info, link);
397 	list_del_init(&ipc_link->link);
398 
399 	ipc_link->ipc_send_compl = ipc_send_compl;
400 	ipc_link->ipc_send_compl_prm = ipc_send_compl_prm;
401 	ipc_link->length = length;
402 	memcpy(ipc_link->inline_data, msg, length);
403 
404 	list_add_tail(&ipc_link->link, &dev->wr_processing_list);
405 	spin_unlock_irqrestore(&dev->wr_processing_spinlock, flags);
406 
407 	write_ipc_from_queue(dev);
408 
409 	return 0;
410 }
411 
412 /**
413  * ipc_send_mng_msg() - Send management message
414  * @dev: ishtp device instance
415  * @msg_code: Message code
416  * @msg: Pointer to message
417  * @size: Length of message
418  *
419  * Send management message to FW
420  *
421  * Return: 0 for success else failure code
422  */
423 static int ipc_send_mng_msg(struct ishtp_device *dev, uint32_t msg_code,
424 	void *msg, size_t size)
425 {
426 	unsigned char	ipc_msg[IPC_FULL_MSG_SIZE];
427 	uint32_t	drbl_val = IPC_BUILD_MNG_MSG(msg_code, size);
428 
429 	memcpy(ipc_msg, &drbl_val, sizeof(uint32_t));
430 	memcpy(ipc_msg + sizeof(uint32_t), msg, size);
431 	return	write_ipc_to_queue(dev, NULL, NULL, ipc_msg,
432 		sizeof(uint32_t) + size);
433 }
434 
435 #define WAIT_FOR_FW_RDY			0x1
436 #define WAIT_FOR_INPUT_RDY		0x2
437 
438 /**
439  * timed_wait_for_timeout() - wait special event with timeout
440  * @dev: ISHTP device pointer
441  * @condition: indicate the condition for waiting
442  * @timeinc: time slice for every wait cycle, in ms
443  * @timeout: time in ms for timeout
444  *
445  * This function will check special event to be ready in a loop, the loop
446  * period is specificd in timeinc. Wait timeout will causes failure.
447  *
448  * Return: 0 for success else failure code
449  */
450 static int timed_wait_for_timeout(struct ishtp_device *dev, int condition,
451 				unsigned int timeinc, unsigned int timeout)
452 {
453 	bool complete = false;
454 	int ret;
455 
456 	do {
457 		if (condition == WAIT_FOR_FW_RDY) {
458 			complete = ishtp_fw_is_ready(dev);
459 		} else if (condition == WAIT_FOR_INPUT_RDY) {
460 			complete = ish_is_input_ready(dev);
461 		} else {
462 			ret = -EINVAL;
463 			goto out;
464 		}
465 
466 		if (!complete) {
467 			unsigned long left_time;
468 
469 			left_time = msleep_interruptible(timeinc);
470 			timeout -= (timeinc - left_time);
471 		}
472 	} while (!complete && timeout > 0);
473 
474 	if (complete)
475 		ret = 0;
476 	else
477 		ret = -EBUSY;
478 
479 out:
480 	return ret;
481 }
482 
483 #define TIME_SLICE_FOR_FW_RDY_MS		100
484 #define TIME_SLICE_FOR_INPUT_RDY_MS		100
485 #define TIMEOUT_FOR_FW_RDY_MS			2000
486 #define TIMEOUT_FOR_INPUT_RDY_MS		2000
487 
488 /**
489  * ish_fw_reset_handler() - FW reset handler
490  * @dev: ishtp device pointer
491  *
492  * Handle FW reset
493  *
494  * Return: 0 for success else failure code
495  */
496 static int ish_fw_reset_handler(struct ishtp_device *dev)
497 {
498 	uint32_t	reset_id;
499 	unsigned long	flags;
500 
501 	/* Read reset ID */
502 	reset_id = ish_reg_read(dev, IPC_REG_ISH2HOST_MSG) & 0xFFFF;
503 
504 	/* Clear IPC output queue */
505 	spin_lock_irqsave(&dev->wr_processing_spinlock, flags);
506 	list_splice_init(&dev->wr_processing_list, &dev->wr_free_list);
507 	spin_unlock_irqrestore(&dev->wr_processing_spinlock, flags);
508 
509 	/* ISHTP notification in IPC_RESET */
510 	ishtp_reset_handler(dev);
511 
512 	if (!ish_is_input_ready(dev))
513 		timed_wait_for_timeout(dev, WAIT_FOR_INPUT_RDY,
514 			TIME_SLICE_FOR_INPUT_RDY_MS, TIMEOUT_FOR_INPUT_RDY_MS);
515 
516 	/* ISH FW is dead */
517 	if (!ish_is_input_ready(dev))
518 		return	-EPIPE;
519 	/*
520 	 * Set HOST2ISH.ILUP. Apparently we need this BEFORE sending
521 	 * RESET_NOTIFY_ACK - FW will be checking for it
522 	 */
523 	ish_set_host_rdy(dev);
524 	/* Send RESET_NOTIFY_ACK (with reset_id) */
525 	ipc_send_mng_msg(dev, MNG_RESET_NOTIFY_ACK, &reset_id,
526 			 sizeof(uint32_t));
527 
528 	/* Wait for ISH FW'es ILUP and ISHTP_READY */
529 	timed_wait_for_timeout(dev, WAIT_FOR_FW_RDY,
530 			TIME_SLICE_FOR_FW_RDY_MS, TIMEOUT_FOR_FW_RDY_MS);
531 	if (!ishtp_fw_is_ready(dev)) {
532 		/* ISH FW is dead */
533 		uint32_t	ish_status;
534 
535 		ish_status = _ish_read_fw_sts_reg(dev);
536 		dev_err(dev->devc,
537 			"[ishtp-ish]: completed reset, ISH is dead (FWSTS = %08X)\n",
538 			ish_status);
539 		return -ENODEV;
540 	}
541 	return	0;
542 }
543 
544 #define TIMEOUT_FOR_HW_RDY_MS			300
545 
546 /**
547  * ish_fw_reset_work_fn() - FW reset worker function
548  * @unused: not used
549  *
550  * Call ish_fw_reset_handler to complete FW reset
551  */
552 static void fw_reset_work_fn(struct work_struct *unused)
553 {
554 	int	rv;
555 
556 	rv = ish_fw_reset_handler(ishtp_dev);
557 	if (!rv) {
558 		/* ISH is ILUP & ISHTP-ready. Restart ISHTP */
559 		msleep_interruptible(TIMEOUT_FOR_HW_RDY_MS);
560 		ishtp_dev->recvd_hw_ready = 1;
561 		wake_up_interruptible(&ishtp_dev->wait_hw_ready);
562 
563 		/* ISHTP notification in IPC_RESET sequence completion */
564 		ishtp_reset_compl_handler(ishtp_dev);
565 	} else
566 		dev_err(ishtp_dev->devc, "[ishtp-ish]: FW reset failed (%d)\n",
567 			rv);
568 }
569 
570 /**
571  * _ish_sync_fw_clock() -Sync FW clock with the OS clock
572  * @dev: ishtp device pointer
573  *
574  * Sync FW and OS time
575  */
576 static void _ish_sync_fw_clock(struct ishtp_device *dev)
577 {
578 	static unsigned long	prev_sync;
579 	uint64_t	usec;
580 
581 	if (prev_sync && jiffies - prev_sync < 20 * HZ)
582 		return;
583 
584 	prev_sync = jiffies;
585 	usec = ktime_to_us(ktime_get_boottime());
586 	ipc_send_mng_msg(dev, MNG_SYNC_FW_CLOCK, &usec, sizeof(uint64_t));
587 }
588 
589 /**
590  * recv_ipc() - Receive and process IPC management messages
591  * @dev: ishtp device instance
592  * @doorbell_val: doorbell value
593  *
594  * This function runs in ISR context.
595  * NOTE: Any other mng command than reset_notify and reset_notify_ack
596  * won't wake BH handler
597  */
598 static void	recv_ipc(struct ishtp_device *dev, uint32_t doorbell_val)
599 {
600 	uint32_t	mng_cmd;
601 
602 	mng_cmd = IPC_HEADER_GET_MNG_CMD(doorbell_val);
603 
604 	switch (mng_cmd) {
605 	default:
606 		break;
607 
608 	case MNG_RX_CMPL_INDICATION:
609 		if (dev->suspend_flag) {
610 			dev->suspend_flag = 0;
611 			wake_up_interruptible(&dev->suspend_wait);
612 		}
613 		if (dev->resume_flag) {
614 			dev->resume_flag = 0;
615 			wake_up_interruptible(&dev->resume_wait);
616 		}
617 
618 		write_ipc_from_queue(dev);
619 		break;
620 
621 	case MNG_RESET_NOTIFY:
622 		if (!ishtp_dev) {
623 			ishtp_dev = dev;
624 			INIT_WORK(&fw_reset_work, fw_reset_work_fn);
625 		}
626 		schedule_work(&fw_reset_work);
627 		break;
628 
629 	case MNG_RESET_NOTIFY_ACK:
630 		dev->recvd_hw_ready = 1;
631 		wake_up_interruptible(&dev->wait_hw_ready);
632 		break;
633 	}
634 }
635 
636 /**
637  * ish_irq_handler() - ISH IRQ handler
638  * @irq: irq number
639  * @dev_id: ishtp device pointer
640  *
641  * ISH IRQ handler. If interrupt is generated and is for ISH it will process
642  * the interrupt.
643  */
644 irqreturn_t ish_irq_handler(int irq, void *dev_id)
645 {
646 	struct ishtp_device	*dev = dev_id;
647 	uint32_t	doorbell_val;
648 	bool	interrupt_generated;
649 
650 	/* Check that it's interrupt from ISH (may be shared) */
651 	interrupt_generated = check_generated_interrupt(dev);
652 
653 	if (!interrupt_generated)
654 		return IRQ_NONE;
655 
656 	doorbell_val = ish_reg_read(dev, IPC_REG_ISH2HOST_DRBL);
657 	if (!IPC_IS_BUSY(doorbell_val))
658 		return IRQ_HANDLED;
659 
660 	if (dev->dev_state == ISHTP_DEV_DISABLED)
661 		return	IRQ_HANDLED;
662 
663 	/* Sanity check: IPC dgram length in header */
664 	if (IPC_HEADER_GET_LENGTH(doorbell_val) > IPC_PAYLOAD_SIZE) {
665 		dev_err(dev->devc,
666 			"IPC hdr - bad length: %u; dropped\n",
667 			(unsigned int)IPC_HEADER_GET_LENGTH(doorbell_val));
668 		goto	eoi;
669 	}
670 
671 	switch (IPC_HEADER_GET_PROTOCOL(doorbell_val)) {
672 	default:
673 		break;
674 	case IPC_PROTOCOL_MNG:
675 		recv_ipc(dev, doorbell_val);
676 		break;
677 	case IPC_PROTOCOL_ISHTP:
678 		ishtp_recv(dev);
679 		break;
680 	}
681 
682 eoi:
683 	/* Update IPC counters */
684 	++dev->ipc_rx_cnt;
685 	dev->ipc_rx_bytes_cnt += IPC_HEADER_GET_LENGTH(doorbell_val);
686 
687 	ish_reg_write(dev, IPC_REG_ISH2HOST_DRBL, 0);
688 	/* Flush write to doorbell */
689 	ish_reg_read(dev, IPC_REG_ISH_HOST_FWSTS);
690 
691 	return	IRQ_HANDLED;
692 }
693 
694 /**
695  * ish_disable_dma() - disable dma communication between host and ISHFW
696  * @dev: ishtp device pointer
697  *
698  * Clear the dma enable bit and wait for dma inactive.
699  *
700  * Return: 0 for success else error code.
701  */
702 int ish_disable_dma(struct ishtp_device *dev)
703 {
704 	unsigned int	dma_delay;
705 
706 	/* Clear the dma enable bit */
707 	ish_reg_write(dev, IPC_REG_ISH_RMP2, 0);
708 
709 	/* wait for dma inactive */
710 	for (dma_delay = 0; dma_delay < MAX_DMA_DELAY &&
711 		_ish_read_fw_sts_reg(dev) & (IPC_ISH_IN_DMA);
712 		dma_delay += 5)
713 		mdelay(5);
714 
715 	if (dma_delay >= MAX_DMA_DELAY) {
716 		dev_err(dev->devc,
717 			"Wait for DMA inactive timeout\n");
718 		return	-EBUSY;
719 	}
720 
721 	return 0;
722 }
723 
724 /**
725  * ish_wakeup() - wakeup ishfw from waiting-for-host state
726  * @dev: ishtp device pointer
727  *
728  * Set the dma enable bit and send a void message to FW,
729  * it wil wakeup FW from waiting-for-host state.
730  */
731 static void ish_wakeup(struct ishtp_device *dev)
732 {
733 	/* Set dma enable bit */
734 	ish_reg_write(dev, IPC_REG_ISH_RMP2, IPC_RMP2_DMA_ENABLED);
735 
736 	/*
737 	 * Send 0 IPC message so that ISH FW wakes up if it was already
738 	 * asleep.
739 	 */
740 	ish_reg_write(dev, IPC_REG_HOST2ISH_DRBL, IPC_DRBL_BUSY_BIT);
741 
742 	/* Flush writes to doorbell and REMAP2 */
743 	ish_reg_read(dev, IPC_REG_ISH_HOST_FWSTS);
744 }
745 
746 /**
747  * _ish_hw_reset() - HW reset
748  * @dev: ishtp device pointer
749  *
750  * Reset ISH HW to recover if any error
751  *
752  * Return: 0 for success else error fault code
753  */
754 static int _ish_hw_reset(struct ishtp_device *dev)
755 {
756 	struct pci_dev *pdev = dev->pdev;
757 	int	rv;
758 	uint16_t csr;
759 
760 	if (!pdev)
761 		return	-ENODEV;
762 
763 	rv = pci_reset_function(pdev);
764 	if (!rv)
765 		dev->dev_state = ISHTP_DEV_RESETTING;
766 
767 	if (!pdev->pm_cap) {
768 		dev_err(&pdev->dev, "Can't reset - no PM caps\n");
769 		return	-EINVAL;
770 	}
771 
772 	/* Disable dma communication between FW and host */
773 	if (ish_disable_dma(dev)) {
774 		dev_err(&pdev->dev,
775 			"Can't reset - stuck with DMA in-progress\n");
776 		return	-EBUSY;
777 	}
778 
779 	pci_read_config_word(pdev, pdev->pm_cap + PCI_PM_CTRL, &csr);
780 
781 	csr &= ~PCI_PM_CTRL_STATE_MASK;
782 	csr |= PCI_D3hot;
783 	pci_write_config_word(pdev, pdev->pm_cap + PCI_PM_CTRL, csr);
784 
785 	mdelay(pdev->d3hot_delay);
786 
787 	csr &= ~PCI_PM_CTRL_STATE_MASK;
788 	csr |= PCI_D0;
789 	pci_write_config_word(pdev, pdev->pm_cap + PCI_PM_CTRL, csr);
790 
791 	/* Now we can enable ISH DMA operation and wakeup ISHFW */
792 	ish_wakeup(dev);
793 
794 	return	0;
795 }
796 
797 /**
798  * _ish_ipc_reset() - IPC reset
799  * @dev: ishtp device pointer
800  *
801  * Resets host and fw IPC and upper layers
802  *
803  * Return: 0 for success else error fault code
804  */
805 static int _ish_ipc_reset(struct ishtp_device *dev)
806 {
807 	struct ipc_rst_payload_type ipc_mng_msg;
808 	int	rv = 0;
809 
810 	ipc_mng_msg.reset_id = 1;
811 	ipc_mng_msg.reserved = 0;
812 
813 	set_host_ready(dev);
814 
815 	/* Clear the incoming doorbell */
816 	ish_reg_write(dev, IPC_REG_ISH2HOST_DRBL, 0);
817 	/* Flush write to doorbell */
818 	ish_reg_read(dev, IPC_REG_ISH_HOST_FWSTS);
819 
820 	dev->recvd_hw_ready = 0;
821 
822 	/* send message */
823 	rv = ipc_send_mng_msg(dev, MNG_RESET_NOTIFY, &ipc_mng_msg,
824 		sizeof(struct ipc_rst_payload_type));
825 	if (rv) {
826 		dev_err(dev->devc, "Failed to send IPC MNG_RESET_NOTIFY\n");
827 		return	rv;
828 	}
829 
830 	wait_event_interruptible_timeout(dev->wait_hw_ready,
831 					 dev->recvd_hw_ready, 2 * HZ);
832 	if (!dev->recvd_hw_ready) {
833 		dev_err(dev->devc, "Timed out waiting for HW ready\n");
834 		rv = -ENODEV;
835 	}
836 
837 	return rv;
838 }
839 
840 /**
841  * ish_hw_start() -Start ISH HW
842  * @dev: ishtp device pointer
843  *
844  * Set host to ready state and wait for FW reset
845  *
846  * Return: 0 for success else error fault code
847  */
848 int ish_hw_start(struct ishtp_device *dev)
849 {
850 	ish_set_host_rdy(dev);
851 
852 	set_host_ready(dev);
853 
854 	/* After that we can enable ISH DMA operation and wakeup ISHFW */
855 	ish_wakeup(dev);
856 
857 	/* wait for FW-initiated reset flow */
858 	if (!dev->recvd_hw_ready)
859 		wait_event_interruptible_timeout(dev->wait_hw_ready,
860 						 dev->recvd_hw_ready,
861 						 10 * HZ);
862 
863 	if (!dev->recvd_hw_ready) {
864 		dev_err(dev->devc,
865 			"[ishtp-ish]: Timed out waiting for FW-initiated reset\n");
866 		return	-ENODEV;
867 	}
868 
869 	return 0;
870 }
871 
872 /**
873  * ish_ipc_get_header() -Get doorbell value
874  * @dev: ishtp device pointer
875  * @length: length of message
876  * @busy: busy status
877  *
878  * Get door bell value from message header
879  *
880  * Return: door bell value
881  */
882 static uint32_t ish_ipc_get_header(struct ishtp_device *dev, int length,
883 				   int busy)
884 {
885 	uint32_t drbl_val;
886 
887 	drbl_val = IPC_BUILD_HEADER(length, IPC_PROTOCOL_ISHTP, busy);
888 
889 	return drbl_val;
890 }
891 
892 static const struct ishtp_hw_ops ish_hw_ops = {
893 	.hw_reset = _ish_hw_reset,
894 	.ipc_reset = _ish_ipc_reset,
895 	.ipc_get_header = ish_ipc_get_header,
896 	.ishtp_read = _ishtp_read,
897 	.write = write_ipc_to_queue,
898 	.get_fw_status = _ish_read_fw_sts_reg,
899 	.sync_fw_clock = _ish_sync_fw_clock,
900 	.ishtp_read_hdr = _ishtp_read_hdr
901 };
902 
903 /**
904  * ish_dev_init() -Initialize ISH devoce
905  * @pdev: PCI device
906  *
907  * Allocate ISHTP device and initialize IPC processing
908  *
909  * Return: ISHTP device instance on success else NULL
910  */
911 struct ishtp_device *ish_dev_init(struct pci_dev *pdev)
912 {
913 	struct ishtp_device *dev;
914 	int	i;
915 
916 	dev = devm_kzalloc(&pdev->dev,
917 			   sizeof(struct ishtp_device) + sizeof(struct ish_hw),
918 			   GFP_KERNEL);
919 	if (!dev)
920 		return NULL;
921 
922 	ishtp_device_init(dev);
923 
924 	init_waitqueue_head(&dev->wait_hw_ready);
925 
926 	spin_lock_init(&dev->wr_processing_spinlock);
927 
928 	/* Init IPC processing and free lists */
929 	INIT_LIST_HEAD(&dev->wr_processing_list);
930 	INIT_LIST_HEAD(&dev->wr_free_list);
931 	for (i = 0; i < IPC_TX_FIFO_SIZE; i++) {
932 		struct wr_msg_ctl_info	*tx_buf;
933 
934 		tx_buf = devm_kzalloc(&pdev->dev,
935 				      sizeof(struct wr_msg_ctl_info),
936 				      GFP_KERNEL);
937 		if (!tx_buf) {
938 			/*
939 			 * IPC buffers may be limited or not available
940 			 * at all - although this shouldn't happen
941 			 */
942 			dev_err(dev->devc,
943 				"[ishtp-ish]: failure in Tx FIFO allocations (%d)\n",
944 				i);
945 			break;
946 		}
947 		list_add_tail(&tx_buf->link, &dev->wr_free_list);
948 	}
949 
950 	dev->ops = &ish_hw_ops;
951 	dev->devc = &pdev->dev;
952 	dev->mtu = IPC_PAYLOAD_SIZE - sizeof(struct ishtp_msg_hdr);
953 	return dev;
954 }
955 
956 /**
957  * ish_device_disable() - Disable ISH device
958  * @dev: ISHTP device pointer
959  *
960  * Disable ISH by clearing host ready to inform firmware.
961  */
962 void	ish_device_disable(struct ishtp_device *dev)
963 {
964 	struct pci_dev *pdev = dev->pdev;
965 
966 	if (!pdev)
967 		return;
968 
969 	/* Disable dma communication between FW and host */
970 	if (ish_disable_dma(dev)) {
971 		dev_err(&pdev->dev,
972 			"Can't reset - stuck with DMA in-progress\n");
973 		return;
974 	}
975 
976 	/* Put ISH to D3hot state for power saving */
977 	pci_set_power_state(pdev, PCI_D3hot);
978 
979 	dev->dev_state = ISHTP_DEV_DISABLED;
980 	ish_clr_host_rdy(dev);
981 }
982