xref: /openbmc/linux/drivers/dma/qcom/hidma_ll.c (revision 4f6cce39)
1 /*
2  * Qualcomm Technologies HIDMA DMA engine low level code
3  *
4  * Copyright (c) 2015-2016, The Linux Foundation. All rights reserved.
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License version 2 and
8  * only version 2 as published by the Free Software Foundation.
9  *
10  * This program is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13  * GNU General Public License for more details.
14  */
15 
16 #include <linux/dmaengine.h>
17 #include <linux/slab.h>
18 #include <linux/interrupt.h>
19 #include <linux/mm.h>
20 #include <linux/highmem.h>
21 #include <linux/dma-mapping.h>
22 #include <linux/delay.h>
23 #include <linux/atomic.h>
24 #include <linux/iopoll.h>
25 #include <linux/kfifo.h>
26 #include <linux/bitops.h>
27 
28 #include "hidma.h"
29 
30 #define HIDMA_EVRE_SIZE			16	/* each EVRE is 16 bytes */
31 
32 #define HIDMA_TRCA_CTRLSTS_REG			0x000
33 #define HIDMA_TRCA_RING_LOW_REG		0x008
34 #define HIDMA_TRCA_RING_HIGH_REG		0x00C
35 #define HIDMA_TRCA_RING_LEN_REG		0x010
36 #define HIDMA_TRCA_DOORBELL_REG		0x400
37 
38 #define HIDMA_EVCA_CTRLSTS_REG			0x000
39 #define HIDMA_EVCA_INTCTRL_REG			0x004
40 #define HIDMA_EVCA_RING_LOW_REG		0x008
41 #define HIDMA_EVCA_RING_HIGH_REG		0x00C
42 #define HIDMA_EVCA_RING_LEN_REG		0x010
43 #define HIDMA_EVCA_WRITE_PTR_REG		0x020
44 #define HIDMA_EVCA_DOORBELL_REG		0x400
45 
46 #define HIDMA_EVCA_IRQ_STAT_REG		0x100
47 #define HIDMA_EVCA_IRQ_CLR_REG			0x108
48 #define HIDMA_EVCA_IRQ_EN_REG			0x110
49 
50 #define HIDMA_EVRE_CFG_IDX			0
51 
52 #define HIDMA_EVRE_ERRINFO_BIT_POS		24
53 #define HIDMA_EVRE_CODE_BIT_POS		28
54 
55 #define HIDMA_EVRE_ERRINFO_MASK		GENMASK(3, 0)
56 #define HIDMA_EVRE_CODE_MASK			GENMASK(3, 0)
57 
58 #define HIDMA_CH_CONTROL_MASK			GENMASK(7, 0)
59 #define HIDMA_CH_STATE_MASK			GENMASK(7, 0)
60 #define HIDMA_CH_STATE_BIT_POS			0x8
61 
62 #define HIDMA_IRQ_EV_CH_EOB_IRQ_BIT_POS	0
63 #define HIDMA_IRQ_EV_CH_WR_RESP_BIT_POS	1
64 #define HIDMA_IRQ_TR_CH_TRE_RD_RSP_ER_BIT_POS	9
65 #define HIDMA_IRQ_TR_CH_DATA_RD_ER_BIT_POS	10
66 #define HIDMA_IRQ_TR_CH_DATA_WR_ER_BIT_POS	11
67 #define HIDMA_IRQ_TR_CH_INVALID_TRE_BIT_POS	14
68 
69 #define ENABLE_IRQS (BIT(HIDMA_IRQ_EV_CH_EOB_IRQ_BIT_POS)	| \
70 		     BIT(HIDMA_IRQ_EV_CH_WR_RESP_BIT_POS)	| \
71 		     BIT(HIDMA_IRQ_TR_CH_TRE_RD_RSP_ER_BIT_POS)	| \
72 		     BIT(HIDMA_IRQ_TR_CH_DATA_RD_ER_BIT_POS)	| \
73 		     BIT(HIDMA_IRQ_TR_CH_DATA_WR_ER_BIT_POS)	| \
74 		     BIT(HIDMA_IRQ_TR_CH_INVALID_TRE_BIT_POS))
75 
76 #define HIDMA_INCREMENT_ITERATOR(iter, size, ring_size)	\
77 do {								\
78 	iter += size;						\
79 	if (iter >= ring_size)					\
80 		iter -= ring_size;				\
81 } while (0)
82 
83 #define HIDMA_CH_STATE(val)	\
84 	((val >> HIDMA_CH_STATE_BIT_POS) & HIDMA_CH_STATE_MASK)
85 
86 #define HIDMA_ERR_INT_MASK				\
87 	(BIT(HIDMA_IRQ_TR_CH_INVALID_TRE_BIT_POS)   |	\
88 	 BIT(HIDMA_IRQ_TR_CH_TRE_RD_RSP_ER_BIT_POS) |	\
89 	 BIT(HIDMA_IRQ_EV_CH_WR_RESP_BIT_POS)	    |	\
90 	 BIT(HIDMA_IRQ_TR_CH_DATA_RD_ER_BIT_POS)    |	\
91 	 BIT(HIDMA_IRQ_TR_CH_DATA_WR_ER_BIT_POS))
92 
93 enum ch_command {
94 	HIDMA_CH_DISABLE = 0,
95 	HIDMA_CH_ENABLE = 1,
96 	HIDMA_CH_SUSPEND = 2,
97 	HIDMA_CH_RESET = 9,
98 };
99 
100 enum ch_state {
101 	HIDMA_CH_DISABLED = 0,
102 	HIDMA_CH_ENABLED = 1,
103 	HIDMA_CH_RUNNING = 2,
104 	HIDMA_CH_SUSPENDED = 3,
105 	HIDMA_CH_STOPPED = 4,
106 };
107 
108 enum tre_type {
109 	HIDMA_TRE_MEMCPY = 3,
110 };
111 
112 enum err_code {
113 	HIDMA_EVRE_STATUS_COMPLETE = 1,
114 	HIDMA_EVRE_STATUS_ERROR = 4,
115 };
116 
117 static int hidma_is_chan_enabled(int state)
118 {
119 	switch (state) {
120 	case HIDMA_CH_ENABLED:
121 	case HIDMA_CH_RUNNING:
122 		return true;
123 	default:
124 		return false;
125 	}
126 }
127 
128 void hidma_ll_free(struct hidma_lldev *lldev, u32 tre_ch)
129 {
130 	struct hidma_tre *tre;
131 
132 	if (tre_ch >= lldev->nr_tres) {
133 		dev_err(lldev->dev, "invalid TRE number in free:%d", tre_ch);
134 		return;
135 	}
136 
137 	tre = &lldev->trepool[tre_ch];
138 	if (atomic_read(&tre->allocated) != true) {
139 		dev_err(lldev->dev, "trying to free an unused TRE:%d", tre_ch);
140 		return;
141 	}
142 
143 	atomic_set(&tre->allocated, 0);
144 }
145 
146 int hidma_ll_request(struct hidma_lldev *lldev, u32 sig, const char *dev_name,
147 		     void (*callback)(void *data), void *data, u32 *tre_ch)
148 {
149 	unsigned int i;
150 	struct hidma_tre *tre;
151 	u32 *tre_local;
152 
153 	if (!tre_ch || !lldev)
154 		return -EINVAL;
155 
156 	/* need to have at least one empty spot in the queue */
157 	for (i = 0; i < lldev->nr_tres - 1; i++) {
158 		if (atomic_add_unless(&lldev->trepool[i].allocated, 1, 1))
159 			break;
160 	}
161 
162 	if (i == (lldev->nr_tres - 1))
163 		return -ENOMEM;
164 
165 	tre = &lldev->trepool[i];
166 	tre->dma_sig = sig;
167 	tre->dev_name = dev_name;
168 	tre->callback = callback;
169 	tre->data = data;
170 	tre->idx = i;
171 	tre->status = 0;
172 	tre->queued = 0;
173 	tre->err_code = 0;
174 	tre->err_info = 0;
175 	tre->lldev = lldev;
176 	tre_local = &tre->tre_local[0];
177 	tre_local[HIDMA_TRE_CFG_IDX] = HIDMA_TRE_MEMCPY;
178 	tre_local[HIDMA_TRE_CFG_IDX] |= (lldev->chidx & 0xFF) << 8;
179 	tre_local[HIDMA_TRE_CFG_IDX] |= BIT(16);	/* set IEOB */
180 	*tre_ch = i;
181 	if (callback)
182 		callback(data);
183 	return 0;
184 }
185 
186 /*
187  * Multiple TREs may be queued and waiting in the pending queue.
188  */
189 static void hidma_ll_tre_complete(unsigned long arg)
190 {
191 	struct hidma_lldev *lldev = (struct hidma_lldev *)arg;
192 	struct hidma_tre *tre;
193 
194 	while (kfifo_out(&lldev->handoff_fifo, &tre, 1)) {
195 		/* call the user if it has been read by the hardware */
196 		if (tre->callback)
197 			tre->callback(tre->data);
198 	}
199 }
200 
201 static int hidma_post_completed(struct hidma_lldev *lldev, u8 err_info,
202 				u8 err_code)
203 {
204 	struct hidma_tre *tre;
205 	unsigned long flags;
206 	u32 tre_iterator;
207 
208 	spin_lock_irqsave(&lldev->lock, flags);
209 
210 	tre_iterator = lldev->tre_processed_off;
211 	tre = lldev->pending_tre_list[tre_iterator / HIDMA_TRE_SIZE];
212 	if (!tre) {
213 		spin_unlock_irqrestore(&lldev->lock, flags);
214 		dev_warn(lldev->dev, "tre_index [%d] and tre out of sync\n",
215 			 tre_iterator / HIDMA_TRE_SIZE);
216 		return -EINVAL;
217 	}
218 	lldev->pending_tre_list[tre->tre_index] = NULL;
219 
220 	/*
221 	 * Keep track of pending TREs that SW is expecting to receive
222 	 * from HW. We got one now. Decrement our counter.
223 	 */
224 	if (atomic_dec_return(&lldev->pending_tre_count) < 0) {
225 		dev_warn(lldev->dev, "tre count mismatch on completion");
226 		atomic_set(&lldev->pending_tre_count, 0);
227 	}
228 
229 	HIDMA_INCREMENT_ITERATOR(tre_iterator, HIDMA_TRE_SIZE,
230 				 lldev->tre_ring_size);
231 	lldev->tre_processed_off = tre_iterator;
232 	spin_unlock_irqrestore(&lldev->lock, flags);
233 
234 	tre->err_info = err_info;
235 	tre->err_code = err_code;
236 	tre->queued = 0;
237 
238 	kfifo_put(&lldev->handoff_fifo, tre);
239 	tasklet_schedule(&lldev->task);
240 
241 	return 0;
242 }
243 
244 /*
245  * Called to handle the interrupt for the channel.
246  * Return a positive number if TRE or EVRE were consumed on this run.
247  * Return a positive number if there are pending TREs or EVREs.
248  * Return 0 if there is nothing to consume or no pending TREs/EVREs found.
249  */
250 static int hidma_handle_tre_completion(struct hidma_lldev *lldev)
251 {
252 	u32 evre_ring_size = lldev->evre_ring_size;
253 	u32 err_info, err_code, evre_write_off;
254 	u32 evre_iterator;
255 	u32 num_completed = 0;
256 
257 	evre_write_off = readl_relaxed(lldev->evca + HIDMA_EVCA_WRITE_PTR_REG);
258 	evre_iterator = lldev->evre_processed_off;
259 
260 	if ((evre_write_off > evre_ring_size) ||
261 	    (evre_write_off % HIDMA_EVRE_SIZE)) {
262 		dev_err(lldev->dev, "HW reports invalid EVRE write offset\n");
263 		return 0;
264 	}
265 
266 	/*
267 	 * By the time control reaches here the number of EVREs and TREs
268 	 * may not match. Only consume the ones that hardware told us.
269 	 */
270 	while ((evre_iterator != evre_write_off)) {
271 		u32 *current_evre = lldev->evre_ring + evre_iterator;
272 		u32 cfg;
273 
274 		cfg = current_evre[HIDMA_EVRE_CFG_IDX];
275 		err_info = cfg >> HIDMA_EVRE_ERRINFO_BIT_POS;
276 		err_info &= HIDMA_EVRE_ERRINFO_MASK;
277 		err_code =
278 		    (cfg >> HIDMA_EVRE_CODE_BIT_POS) & HIDMA_EVRE_CODE_MASK;
279 
280 		if (hidma_post_completed(lldev, err_info, err_code))
281 			break;
282 
283 		HIDMA_INCREMENT_ITERATOR(evre_iterator, HIDMA_EVRE_SIZE,
284 					 evre_ring_size);
285 
286 		/*
287 		 * Read the new event descriptor written by the HW.
288 		 * As we are processing the delivered events, other events
289 		 * get queued to the SW for processing.
290 		 */
291 		evre_write_off =
292 		    readl_relaxed(lldev->evca + HIDMA_EVCA_WRITE_PTR_REG);
293 		num_completed++;
294 
295 		/*
296 		 * An error interrupt might have arrived while we are processing
297 		 * the completed interrupt.
298 		 */
299 		if (!hidma_ll_isenabled(lldev))
300 			break;
301 	}
302 
303 	if (num_completed) {
304 		u32 evre_read_off = (lldev->evre_processed_off +
305 				     HIDMA_EVRE_SIZE * num_completed);
306 		evre_read_off = evre_read_off % evre_ring_size;
307 		writel(evre_read_off, lldev->evca + HIDMA_EVCA_DOORBELL_REG);
308 
309 		/* record the last processed tre offset */
310 		lldev->evre_processed_off = evre_read_off;
311 	}
312 
313 	return num_completed;
314 }
315 
316 void hidma_cleanup_pending_tre(struct hidma_lldev *lldev, u8 err_info,
317 			       u8 err_code)
318 {
319 	while (atomic_read(&lldev->pending_tre_count)) {
320 		if (hidma_post_completed(lldev, err_info, err_code))
321 			break;
322 	}
323 }
324 
325 static int hidma_ll_reset(struct hidma_lldev *lldev)
326 {
327 	u32 val;
328 	int ret;
329 
330 	val = readl(lldev->trca + HIDMA_TRCA_CTRLSTS_REG);
331 	val &= ~(HIDMA_CH_CONTROL_MASK << 16);
332 	val |= HIDMA_CH_RESET << 16;
333 	writel(val, lldev->trca + HIDMA_TRCA_CTRLSTS_REG);
334 
335 	/*
336 	 * Delay 10ms after reset to allow DMA logic to quiesce.
337 	 * Do a polled read up to 1ms and 10ms maximum.
338 	 */
339 	ret = readl_poll_timeout(lldev->trca + HIDMA_TRCA_CTRLSTS_REG, val,
340 				 HIDMA_CH_STATE(val) == HIDMA_CH_DISABLED,
341 				 1000, 10000);
342 	if (ret) {
343 		dev_err(lldev->dev, "transfer channel did not reset\n");
344 		return ret;
345 	}
346 
347 	val = readl(lldev->evca + HIDMA_EVCA_CTRLSTS_REG);
348 	val &= ~(HIDMA_CH_CONTROL_MASK << 16);
349 	val |= HIDMA_CH_RESET << 16;
350 	writel(val, lldev->evca + HIDMA_EVCA_CTRLSTS_REG);
351 
352 	/*
353 	 * Delay 10ms after reset to allow DMA logic to quiesce.
354 	 * Do a polled read up to 1ms and 10ms maximum.
355 	 */
356 	ret = readl_poll_timeout(lldev->evca + HIDMA_EVCA_CTRLSTS_REG, val,
357 				 HIDMA_CH_STATE(val) == HIDMA_CH_DISABLED,
358 				 1000, 10000);
359 	if (ret)
360 		return ret;
361 
362 	lldev->trch_state = HIDMA_CH_DISABLED;
363 	lldev->evch_state = HIDMA_CH_DISABLED;
364 	return 0;
365 }
366 
367 /*
368  * The interrupt handler for HIDMA will try to consume as many pending
369  * EVRE from the event queue as possible. Each EVRE has an associated
370  * TRE that holds the user interface parameters. EVRE reports the
371  * result of the transaction. Hardware guarantees ordering between EVREs
372  * and TREs. We use last processed offset to figure out which TRE is
373  * associated with which EVRE. If two TREs are consumed by HW, the EVREs
374  * are in order in the event ring.
375  *
376  * This handler will do a one pass for consuming EVREs. Other EVREs may
377  * be delivered while we are working. It will try to consume incoming
378  * EVREs one more time and return.
379  *
380  * For unprocessed EVREs, hardware will trigger another interrupt until
381  * all the interrupt bits are cleared.
382  *
383  * Hardware guarantees that by the time interrupt is observed, all data
384  * transactions in flight are delivered to their respective places and
385  * are visible to the CPU.
386  *
387  * On demand paging for IOMMU is only supported for PCIe via PRI
388  * (Page Request Interface) not for HIDMA. All other hardware instances
389  * including HIDMA work on pinned DMA addresses.
390  *
391  * HIDMA is not aware of IOMMU presence since it follows the DMA API. All
392  * IOMMU latency will be built into the data movement time. By the time
393  * interrupt happens, IOMMU lookups + data movement has already taken place.
394  *
395  * While the first read in a typical PCI endpoint ISR flushes all outstanding
396  * requests traditionally to the destination, this concept does not apply
397  * here for this HW.
398  */
399 static void hidma_ll_int_handler_internal(struct hidma_lldev *lldev, int cause)
400 {
401 	if (cause & HIDMA_ERR_INT_MASK) {
402 		dev_err(lldev->dev, "error 0x%x, disabling...\n",
403 				cause);
404 
405 		/* Clear out pending interrupts */
406 		writel(cause, lldev->evca + HIDMA_EVCA_IRQ_CLR_REG);
407 
408 		/* No further submissions. */
409 		hidma_ll_disable(lldev);
410 
411 		/* Driver completes the txn and intimates the client.*/
412 		hidma_cleanup_pending_tre(lldev, 0xFF,
413 					  HIDMA_EVRE_STATUS_ERROR);
414 
415 		return;
416 	}
417 
418 	/*
419 	 * Fine tuned for this HW...
420 	 *
421 	 * This ISR has been designed for this particular hardware. Relaxed
422 	 * read and write accessors are used for performance reasons due to
423 	 * interrupt delivery guarantees. Do not copy this code blindly and
424 	 * expect that to work.
425 	 *
426 	 * Try to consume as many EVREs as possible.
427 	 */
428 	hidma_handle_tre_completion(lldev);
429 
430 	/* We consumed TREs or there are pending TREs or EVREs. */
431 	writel_relaxed(cause, lldev->evca + HIDMA_EVCA_IRQ_CLR_REG);
432 }
433 
434 irqreturn_t hidma_ll_inthandler(int chirq, void *arg)
435 {
436 	struct hidma_lldev *lldev = arg;
437 	u32 status;
438 	u32 enable;
439 	u32 cause;
440 
441 	status = readl_relaxed(lldev->evca + HIDMA_EVCA_IRQ_STAT_REG);
442 	enable = readl_relaxed(lldev->evca + HIDMA_EVCA_IRQ_EN_REG);
443 	cause = status & enable;
444 
445 	while (cause) {
446 		hidma_ll_int_handler_internal(lldev, cause);
447 
448 		/*
449 		 * Another interrupt might have arrived while we are
450 		 * processing this one. Read the new cause.
451 		 */
452 		status = readl_relaxed(lldev->evca + HIDMA_EVCA_IRQ_STAT_REG);
453 		enable = readl_relaxed(lldev->evca + HIDMA_EVCA_IRQ_EN_REG);
454 		cause = status & enable;
455 	}
456 
457 	return IRQ_HANDLED;
458 }
459 
460 irqreturn_t hidma_ll_inthandler_msi(int chirq, void *arg, int cause)
461 {
462 	struct hidma_lldev *lldev = arg;
463 
464 	hidma_ll_int_handler_internal(lldev, cause);
465 	return IRQ_HANDLED;
466 }
467 
468 int hidma_ll_enable(struct hidma_lldev *lldev)
469 {
470 	u32 val;
471 	int ret;
472 
473 	val = readl(lldev->evca + HIDMA_EVCA_CTRLSTS_REG);
474 	val &= ~(HIDMA_CH_CONTROL_MASK << 16);
475 	val |= HIDMA_CH_ENABLE << 16;
476 	writel(val, lldev->evca + HIDMA_EVCA_CTRLSTS_REG);
477 
478 	ret = readl_poll_timeout(lldev->evca + HIDMA_EVCA_CTRLSTS_REG, val,
479 				 hidma_is_chan_enabled(HIDMA_CH_STATE(val)),
480 				 1000, 10000);
481 	if (ret) {
482 		dev_err(lldev->dev, "event channel did not get enabled\n");
483 		return ret;
484 	}
485 
486 	val = readl(lldev->trca + HIDMA_TRCA_CTRLSTS_REG);
487 	val &= ~(HIDMA_CH_CONTROL_MASK << 16);
488 	val |= HIDMA_CH_ENABLE << 16;
489 	writel(val, lldev->trca + HIDMA_TRCA_CTRLSTS_REG);
490 
491 	ret = readl_poll_timeout(lldev->trca + HIDMA_TRCA_CTRLSTS_REG, val,
492 				 hidma_is_chan_enabled(HIDMA_CH_STATE(val)),
493 				 1000, 10000);
494 	if (ret) {
495 		dev_err(lldev->dev, "transfer channel did not get enabled\n");
496 		return ret;
497 	}
498 
499 	lldev->trch_state = HIDMA_CH_ENABLED;
500 	lldev->evch_state = HIDMA_CH_ENABLED;
501 
502 	return 0;
503 }
504 
505 void hidma_ll_start(struct hidma_lldev *lldev)
506 {
507 	unsigned long irqflags;
508 
509 	spin_lock_irqsave(&lldev->lock, irqflags);
510 	writel(lldev->tre_write_offset, lldev->trca + HIDMA_TRCA_DOORBELL_REG);
511 	spin_unlock_irqrestore(&lldev->lock, irqflags);
512 }
513 
514 bool hidma_ll_isenabled(struct hidma_lldev *lldev)
515 {
516 	u32 val;
517 
518 	val = readl(lldev->trca + HIDMA_TRCA_CTRLSTS_REG);
519 	lldev->trch_state = HIDMA_CH_STATE(val);
520 	val = readl(lldev->evca + HIDMA_EVCA_CTRLSTS_REG);
521 	lldev->evch_state = HIDMA_CH_STATE(val);
522 
523 	/* both channels have to be enabled before calling this function */
524 	if (hidma_is_chan_enabled(lldev->trch_state) &&
525 	    hidma_is_chan_enabled(lldev->evch_state))
526 		return true;
527 
528 	return false;
529 }
530 
531 void hidma_ll_queue_request(struct hidma_lldev *lldev, u32 tre_ch)
532 {
533 	struct hidma_tre *tre;
534 	unsigned long flags;
535 
536 	tre = &lldev->trepool[tre_ch];
537 
538 	/* copy the TRE into its location in the TRE ring */
539 	spin_lock_irqsave(&lldev->lock, flags);
540 	tre->tre_index = lldev->tre_write_offset / HIDMA_TRE_SIZE;
541 	lldev->pending_tre_list[tre->tre_index] = tre;
542 	memcpy(lldev->tre_ring + lldev->tre_write_offset,
543 			&tre->tre_local[0], HIDMA_TRE_SIZE);
544 	tre->err_code = 0;
545 	tre->err_info = 0;
546 	tre->queued = 1;
547 	atomic_inc(&lldev->pending_tre_count);
548 	lldev->tre_write_offset = (lldev->tre_write_offset + HIDMA_TRE_SIZE)
549 					% lldev->tre_ring_size;
550 	spin_unlock_irqrestore(&lldev->lock, flags);
551 }
552 
553 /*
554  * Note that even though we stop this channel if there is a pending transaction
555  * in flight it will complete and follow the callback. This request will
556  * prevent further requests to be made.
557  */
558 int hidma_ll_disable(struct hidma_lldev *lldev)
559 {
560 	u32 val;
561 	int ret;
562 
563 	/* The channel needs to be in working state */
564 	if (!hidma_ll_isenabled(lldev))
565 		return 0;
566 
567 	val = readl(lldev->trca + HIDMA_TRCA_CTRLSTS_REG);
568 	val &= ~(HIDMA_CH_CONTROL_MASK << 16);
569 	val |= HIDMA_CH_SUSPEND << 16;
570 	writel(val, lldev->trca + HIDMA_TRCA_CTRLSTS_REG);
571 
572 	/*
573 	 * Start the wait right after the suspend is confirmed.
574 	 * Do a polled read up to 1ms and 10ms maximum.
575 	 */
576 	ret = readl_poll_timeout(lldev->trca + HIDMA_TRCA_CTRLSTS_REG, val,
577 				 HIDMA_CH_STATE(val) == HIDMA_CH_SUSPENDED,
578 				 1000, 10000);
579 	if (ret)
580 		return ret;
581 
582 	val = readl(lldev->evca + HIDMA_EVCA_CTRLSTS_REG);
583 	val &= ~(HIDMA_CH_CONTROL_MASK << 16);
584 	val |= HIDMA_CH_SUSPEND << 16;
585 	writel(val, lldev->evca + HIDMA_EVCA_CTRLSTS_REG);
586 
587 	/*
588 	 * Start the wait right after the suspend is confirmed
589 	 * Delay up to 10ms after reset to allow DMA logic to quiesce.
590 	 */
591 	ret = readl_poll_timeout(lldev->evca + HIDMA_EVCA_CTRLSTS_REG, val,
592 				 HIDMA_CH_STATE(val) == HIDMA_CH_SUSPENDED,
593 				 1000, 10000);
594 	if (ret)
595 		return ret;
596 
597 	lldev->trch_state = HIDMA_CH_SUSPENDED;
598 	lldev->evch_state = HIDMA_CH_SUSPENDED;
599 	return 0;
600 }
601 
602 void hidma_ll_set_transfer_params(struct hidma_lldev *lldev, u32 tre_ch,
603 				  dma_addr_t src, dma_addr_t dest, u32 len,
604 				  u32 flags)
605 {
606 	struct hidma_tre *tre;
607 	u32 *tre_local;
608 
609 	if (tre_ch >= lldev->nr_tres) {
610 		dev_err(lldev->dev, "invalid TRE number in transfer params:%d",
611 			tre_ch);
612 		return;
613 	}
614 
615 	tre = &lldev->trepool[tre_ch];
616 	if (atomic_read(&tre->allocated) != true) {
617 		dev_err(lldev->dev, "trying to set params on an unused TRE:%d",
618 			tre_ch);
619 		return;
620 	}
621 
622 	tre_local = &tre->tre_local[0];
623 	tre_local[HIDMA_TRE_LEN_IDX] = len;
624 	tre_local[HIDMA_TRE_SRC_LOW_IDX] = lower_32_bits(src);
625 	tre_local[HIDMA_TRE_SRC_HI_IDX] = upper_32_bits(src);
626 	tre_local[HIDMA_TRE_DEST_LOW_IDX] = lower_32_bits(dest);
627 	tre_local[HIDMA_TRE_DEST_HI_IDX] = upper_32_bits(dest);
628 	tre->int_flags = flags;
629 }
630 
631 /*
632  * Called during initialization and after an error condition
633  * to restore hardware state.
634  */
635 int hidma_ll_setup(struct hidma_lldev *lldev)
636 {
637 	int rc;
638 	u64 addr;
639 	u32 val;
640 	u32 nr_tres = lldev->nr_tres;
641 
642 	atomic_set(&lldev->pending_tre_count, 0);
643 	lldev->tre_processed_off = 0;
644 	lldev->evre_processed_off = 0;
645 	lldev->tre_write_offset = 0;
646 
647 	/* disable interrupts */
648 	writel(0, lldev->evca + HIDMA_EVCA_IRQ_EN_REG);
649 
650 	/* clear all pending interrupts */
651 	val = readl(lldev->evca + HIDMA_EVCA_IRQ_STAT_REG);
652 	writel(val, lldev->evca + HIDMA_EVCA_IRQ_CLR_REG);
653 
654 	rc = hidma_ll_reset(lldev);
655 	if (rc)
656 		return rc;
657 
658 	/*
659 	 * Clear all pending interrupts again.
660 	 * Otherwise, we observe reset complete interrupts.
661 	 */
662 	val = readl(lldev->evca + HIDMA_EVCA_IRQ_STAT_REG);
663 	writel(val, lldev->evca + HIDMA_EVCA_IRQ_CLR_REG);
664 
665 	/* disable interrupts again after reset */
666 	writel(0, lldev->evca + HIDMA_EVCA_IRQ_EN_REG);
667 
668 	addr = lldev->tre_dma;
669 	writel(lower_32_bits(addr), lldev->trca + HIDMA_TRCA_RING_LOW_REG);
670 	writel(upper_32_bits(addr), lldev->trca + HIDMA_TRCA_RING_HIGH_REG);
671 	writel(lldev->tre_ring_size, lldev->trca + HIDMA_TRCA_RING_LEN_REG);
672 
673 	addr = lldev->evre_dma;
674 	writel(lower_32_bits(addr), lldev->evca + HIDMA_EVCA_RING_LOW_REG);
675 	writel(upper_32_bits(addr), lldev->evca + HIDMA_EVCA_RING_HIGH_REG);
676 	writel(HIDMA_EVRE_SIZE * nr_tres,
677 			lldev->evca + HIDMA_EVCA_RING_LEN_REG);
678 
679 	/* configure interrupts */
680 	hidma_ll_setup_irq(lldev, lldev->msi_support);
681 
682 	rc = hidma_ll_enable(lldev);
683 	if (rc)
684 		return rc;
685 
686 	return rc;
687 }
688 
689 void hidma_ll_setup_irq(struct hidma_lldev *lldev, bool msi)
690 {
691 	u32 val;
692 
693 	lldev->msi_support = msi;
694 
695 	/* disable interrupts again after reset */
696 	writel(0, lldev->evca + HIDMA_EVCA_IRQ_CLR_REG);
697 	writel(0, lldev->evca + HIDMA_EVCA_IRQ_EN_REG);
698 
699 	/* support IRQ by default */
700 	val = readl(lldev->evca + HIDMA_EVCA_INTCTRL_REG);
701 	val &= ~0xF;
702 	if (!lldev->msi_support)
703 		val = val | 0x1;
704 	writel(val, lldev->evca + HIDMA_EVCA_INTCTRL_REG);
705 
706 	/* clear all pending interrupts and enable them */
707 	writel(ENABLE_IRQS, lldev->evca + HIDMA_EVCA_IRQ_CLR_REG);
708 	writel(ENABLE_IRQS, lldev->evca + HIDMA_EVCA_IRQ_EN_REG);
709 }
710 
711 struct hidma_lldev *hidma_ll_init(struct device *dev, u32 nr_tres,
712 				  void __iomem *trca, void __iomem *evca,
713 				  u8 chidx)
714 {
715 	u32 required_bytes;
716 	struct hidma_lldev *lldev;
717 	int rc;
718 	size_t sz;
719 
720 	if (!trca || !evca || !dev || !nr_tres)
721 		return NULL;
722 
723 	/* need at least four TREs */
724 	if (nr_tres < 4)
725 		return NULL;
726 
727 	/* need an extra space */
728 	nr_tres += 1;
729 
730 	lldev = devm_kzalloc(dev, sizeof(struct hidma_lldev), GFP_KERNEL);
731 	if (!lldev)
732 		return NULL;
733 
734 	lldev->evca = evca;
735 	lldev->trca = trca;
736 	lldev->dev = dev;
737 	sz = sizeof(struct hidma_tre);
738 	lldev->trepool = devm_kcalloc(lldev->dev, nr_tres, sz, GFP_KERNEL);
739 	if (!lldev->trepool)
740 		return NULL;
741 
742 	required_bytes = sizeof(lldev->pending_tre_list[0]);
743 	lldev->pending_tre_list = devm_kcalloc(dev, nr_tres, required_bytes,
744 					       GFP_KERNEL);
745 	if (!lldev->pending_tre_list)
746 		return NULL;
747 
748 	sz = (HIDMA_TRE_SIZE + 1) * nr_tres;
749 	lldev->tre_ring = dmam_alloc_coherent(dev, sz, &lldev->tre_dma,
750 					      GFP_KERNEL);
751 	if (!lldev->tre_ring)
752 		return NULL;
753 
754 	memset(lldev->tre_ring, 0, (HIDMA_TRE_SIZE + 1) * nr_tres);
755 	lldev->tre_ring_size = HIDMA_TRE_SIZE * nr_tres;
756 	lldev->nr_tres = nr_tres;
757 
758 	/* the TRE ring has to be TRE_SIZE aligned */
759 	if (!IS_ALIGNED(lldev->tre_dma, HIDMA_TRE_SIZE)) {
760 		u8 tre_ring_shift;
761 
762 		tre_ring_shift = lldev->tre_dma % HIDMA_TRE_SIZE;
763 		tre_ring_shift = HIDMA_TRE_SIZE - tre_ring_shift;
764 		lldev->tre_dma += tre_ring_shift;
765 		lldev->tre_ring += tre_ring_shift;
766 	}
767 
768 	sz = (HIDMA_EVRE_SIZE + 1) * nr_tres;
769 	lldev->evre_ring = dmam_alloc_coherent(dev, sz, &lldev->evre_dma,
770 					       GFP_KERNEL);
771 	if (!lldev->evre_ring)
772 		return NULL;
773 
774 	memset(lldev->evre_ring, 0, (HIDMA_EVRE_SIZE + 1) * nr_tres);
775 	lldev->evre_ring_size = HIDMA_EVRE_SIZE * nr_tres;
776 
777 	/* the EVRE ring has to be EVRE_SIZE aligned */
778 	if (!IS_ALIGNED(lldev->evre_dma, HIDMA_EVRE_SIZE)) {
779 		u8 evre_ring_shift;
780 
781 		evre_ring_shift = lldev->evre_dma % HIDMA_EVRE_SIZE;
782 		evre_ring_shift = HIDMA_EVRE_SIZE - evre_ring_shift;
783 		lldev->evre_dma += evre_ring_shift;
784 		lldev->evre_ring += evre_ring_shift;
785 	}
786 	lldev->nr_tres = nr_tres;
787 	lldev->chidx = chidx;
788 
789 	sz = nr_tres * sizeof(struct hidma_tre *);
790 	rc = kfifo_alloc(&lldev->handoff_fifo, sz, GFP_KERNEL);
791 	if (rc)
792 		return NULL;
793 
794 	rc = hidma_ll_setup(lldev);
795 	if (rc)
796 		return NULL;
797 
798 	spin_lock_init(&lldev->lock);
799 	tasklet_init(&lldev->task, hidma_ll_tre_complete, (unsigned long)lldev);
800 	lldev->initialized = 1;
801 	writel(ENABLE_IRQS, lldev->evca + HIDMA_EVCA_IRQ_EN_REG);
802 	return lldev;
803 }
804 
805 int hidma_ll_uninit(struct hidma_lldev *lldev)
806 {
807 	u32 required_bytes;
808 	int rc = 0;
809 	u32 val;
810 
811 	if (!lldev)
812 		return -ENODEV;
813 
814 	if (!lldev->initialized)
815 		return 0;
816 
817 	lldev->initialized = 0;
818 
819 	required_bytes = sizeof(struct hidma_tre) * lldev->nr_tres;
820 	tasklet_kill(&lldev->task);
821 	memset(lldev->trepool, 0, required_bytes);
822 	lldev->trepool = NULL;
823 	atomic_set(&lldev->pending_tre_count, 0);
824 	lldev->tre_write_offset = 0;
825 
826 	rc = hidma_ll_reset(lldev);
827 
828 	/*
829 	 * Clear all pending interrupts again.
830 	 * Otherwise, we observe reset complete interrupts.
831 	 */
832 	val = readl(lldev->evca + HIDMA_EVCA_IRQ_STAT_REG);
833 	writel(val, lldev->evca + HIDMA_EVCA_IRQ_CLR_REG);
834 	writel(0, lldev->evca + HIDMA_EVCA_IRQ_EN_REG);
835 	return rc;
836 }
837 
838 enum dma_status hidma_ll_status(struct hidma_lldev *lldev, u32 tre_ch)
839 {
840 	enum dma_status ret = DMA_ERROR;
841 	struct hidma_tre *tre;
842 	unsigned long flags;
843 	u8 err_code;
844 
845 	spin_lock_irqsave(&lldev->lock, flags);
846 
847 	tre = &lldev->trepool[tre_ch];
848 	err_code = tre->err_code;
849 
850 	if (err_code & HIDMA_EVRE_STATUS_COMPLETE)
851 		ret = DMA_COMPLETE;
852 	else if (err_code & HIDMA_EVRE_STATUS_ERROR)
853 		ret = DMA_ERROR;
854 	else
855 		ret = DMA_IN_PROGRESS;
856 	spin_unlock_irqrestore(&lldev->lock, flags);
857 
858 	return ret;
859 }
860