xref: /linux/drivers/crypto/ccree/cc_request_mgr.c (revision e65e175b07bef5974045cc42238de99057669ca7)
1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (C) 2012-2019 ARM Limited (or its affiliates). */
3 
4 #include <linux/kernel.h>
5 #include <linux/nospec.h>
6 #include "cc_driver.h"
7 #include "cc_buffer_mgr.h"
8 #include "cc_request_mgr.h"
9 #include "cc_pm.h"
10 
11 #define CC_MAX_POLL_ITER	10
12 /* The highest descriptor count in used */
13 #define CC_MAX_DESC_SEQ_LEN	23
14 
15 struct cc_req_mgr_handle {
16 	/* Request manager resources */
17 	unsigned int hw_queue_size; /* HW capability */
18 	unsigned int min_free_hw_slots;
19 	unsigned int max_used_sw_slots;
20 	struct cc_crypto_req req_queue[MAX_REQUEST_QUEUE_SIZE];
21 	u32 req_queue_head;
22 	u32 req_queue_tail;
23 	u32 axi_completed;
24 	u32 q_free_slots;
25 	/* This lock protects access to HW register
26 	 * that must be single request at a time
27 	 */
28 	spinlock_t hw_lock;
29 	struct cc_hw_desc compl_desc;
30 	u8 *dummy_comp_buff;
31 	dma_addr_t dummy_comp_buff_dma;
32 
33 	/* backlog queue */
34 	struct list_head backlog;
35 	unsigned int bl_len;
36 	spinlock_t bl_lock; /* protect backlog queue */
37 
38 #ifdef COMP_IN_WQ
39 	struct workqueue_struct *workq;
40 	struct delayed_work compwork;
41 #else
42 	struct tasklet_struct comptask;
43 #endif
44 };
45 
46 struct cc_bl_item {
47 	struct cc_crypto_req creq;
48 	struct cc_hw_desc desc[CC_MAX_DESC_SEQ_LEN];
49 	unsigned int len;
50 	struct list_head list;
51 	bool notif;
52 };
53 
54 static const u32 cc_cpp_int_masks[CC_CPP_NUM_ALGS][CC_CPP_NUM_SLOTS] = {
55 	{ BIT(CC_HOST_IRR_REE_OP_ABORTED_AES_0_INT_BIT_SHIFT),
56 	  BIT(CC_HOST_IRR_REE_OP_ABORTED_AES_1_INT_BIT_SHIFT),
57 	  BIT(CC_HOST_IRR_REE_OP_ABORTED_AES_2_INT_BIT_SHIFT),
58 	  BIT(CC_HOST_IRR_REE_OP_ABORTED_AES_3_INT_BIT_SHIFT),
59 	  BIT(CC_HOST_IRR_REE_OP_ABORTED_AES_4_INT_BIT_SHIFT),
60 	  BIT(CC_HOST_IRR_REE_OP_ABORTED_AES_5_INT_BIT_SHIFT),
61 	  BIT(CC_HOST_IRR_REE_OP_ABORTED_AES_6_INT_BIT_SHIFT),
62 	  BIT(CC_HOST_IRR_REE_OP_ABORTED_AES_7_INT_BIT_SHIFT) },
63 	{ BIT(CC_HOST_IRR_REE_OP_ABORTED_SM_0_INT_BIT_SHIFT),
64 	  BIT(CC_HOST_IRR_REE_OP_ABORTED_SM_1_INT_BIT_SHIFT),
65 	  BIT(CC_HOST_IRR_REE_OP_ABORTED_SM_2_INT_BIT_SHIFT),
66 	  BIT(CC_HOST_IRR_REE_OP_ABORTED_SM_3_INT_BIT_SHIFT),
67 	  BIT(CC_HOST_IRR_REE_OP_ABORTED_SM_4_INT_BIT_SHIFT),
68 	  BIT(CC_HOST_IRR_REE_OP_ABORTED_SM_5_INT_BIT_SHIFT),
69 	  BIT(CC_HOST_IRR_REE_OP_ABORTED_SM_6_INT_BIT_SHIFT),
70 	  BIT(CC_HOST_IRR_REE_OP_ABORTED_SM_7_INT_BIT_SHIFT) }
71 };
72 
73 static void comp_handler(unsigned long devarg);
74 #ifdef COMP_IN_WQ
75 static void comp_work_handler(struct work_struct *work);
76 #endif
77 
78 static inline u32 cc_cpp_int_mask(enum cc_cpp_alg alg, int slot)
79 {
80 	alg = array_index_nospec(alg, CC_CPP_NUM_ALGS);
81 	slot = array_index_nospec(slot, CC_CPP_NUM_SLOTS);
82 
83 	return cc_cpp_int_masks[alg][slot];
84 }
85 
86 void cc_req_mgr_fini(struct cc_drvdata *drvdata)
87 {
88 	struct cc_req_mgr_handle *req_mgr_h = drvdata->request_mgr_handle;
89 	struct device *dev = drvdata_to_dev(drvdata);
90 
91 	if (!req_mgr_h)
92 		return; /* Not allocated */
93 
94 	if (req_mgr_h->dummy_comp_buff_dma) {
95 		dma_free_coherent(dev, sizeof(u32), req_mgr_h->dummy_comp_buff,
96 				  req_mgr_h->dummy_comp_buff_dma);
97 	}
98 
99 	dev_dbg(dev, "max_used_hw_slots=%d\n", (req_mgr_h->hw_queue_size -
100 						req_mgr_h->min_free_hw_slots));
101 	dev_dbg(dev, "max_used_sw_slots=%d\n", req_mgr_h->max_used_sw_slots);
102 
103 #ifdef COMP_IN_WQ
104 	destroy_workqueue(req_mgr_h->workq);
105 #else
106 	/* Kill tasklet */
107 	tasklet_kill(&req_mgr_h->comptask);
108 #endif
109 	kfree_sensitive(req_mgr_h);
110 	drvdata->request_mgr_handle = NULL;
111 }
112 
113 int cc_req_mgr_init(struct cc_drvdata *drvdata)
114 {
115 	struct cc_req_mgr_handle *req_mgr_h;
116 	struct device *dev = drvdata_to_dev(drvdata);
117 	int rc = 0;
118 
119 	req_mgr_h = kzalloc(sizeof(*req_mgr_h), GFP_KERNEL);
120 	if (!req_mgr_h) {
121 		rc = -ENOMEM;
122 		goto req_mgr_init_err;
123 	}
124 
125 	drvdata->request_mgr_handle = req_mgr_h;
126 
127 	spin_lock_init(&req_mgr_h->hw_lock);
128 	spin_lock_init(&req_mgr_h->bl_lock);
129 	INIT_LIST_HEAD(&req_mgr_h->backlog);
130 
131 #ifdef COMP_IN_WQ
132 	dev_dbg(dev, "Initializing completion workqueue\n");
133 	req_mgr_h->workq = create_singlethread_workqueue("ccree");
134 	if (!req_mgr_h->workq) {
135 		dev_err(dev, "Failed creating work queue\n");
136 		rc = -ENOMEM;
137 		goto req_mgr_init_err;
138 	}
139 	INIT_DELAYED_WORK(&req_mgr_h->compwork, comp_work_handler);
140 #else
141 	dev_dbg(dev, "Initializing completion tasklet\n");
142 	tasklet_init(&req_mgr_h->comptask, comp_handler,
143 		     (unsigned long)drvdata);
144 #endif
145 	req_mgr_h->hw_queue_size = cc_ioread(drvdata,
146 					     CC_REG(DSCRPTR_QUEUE_SRAM_SIZE));
147 	dev_dbg(dev, "hw_queue_size=0x%08X\n", req_mgr_h->hw_queue_size);
148 	if (req_mgr_h->hw_queue_size < MIN_HW_QUEUE_SIZE) {
149 		dev_err(dev, "Invalid HW queue size = %u (Min. required is %u)\n",
150 			req_mgr_h->hw_queue_size, MIN_HW_QUEUE_SIZE);
151 		rc = -ENOMEM;
152 		goto req_mgr_init_err;
153 	}
154 	req_mgr_h->min_free_hw_slots = req_mgr_h->hw_queue_size;
155 	req_mgr_h->max_used_sw_slots = 0;
156 
157 	/* Allocate DMA word for "dummy" completion descriptor use */
158 	req_mgr_h->dummy_comp_buff =
159 		dma_alloc_coherent(dev, sizeof(u32),
160 				   &req_mgr_h->dummy_comp_buff_dma,
161 				   GFP_KERNEL);
162 	if (!req_mgr_h->dummy_comp_buff) {
163 		dev_err(dev, "Not enough memory to allocate DMA (%zu) dropped buffer\n",
164 			sizeof(u32));
165 		rc = -ENOMEM;
166 		goto req_mgr_init_err;
167 	}
168 
169 	/* Init. "dummy" completion descriptor */
170 	hw_desc_init(&req_mgr_h->compl_desc);
171 	set_din_const(&req_mgr_h->compl_desc, 0, sizeof(u32));
172 	set_dout_dlli(&req_mgr_h->compl_desc, req_mgr_h->dummy_comp_buff_dma,
173 		      sizeof(u32), NS_BIT, 1);
174 	set_flow_mode(&req_mgr_h->compl_desc, BYPASS);
175 	set_queue_last_ind(drvdata, &req_mgr_h->compl_desc);
176 
177 	return 0;
178 
179 req_mgr_init_err:
180 	cc_req_mgr_fini(drvdata);
181 	return rc;
182 }
183 
184 static void enqueue_seq(struct cc_drvdata *drvdata, struct cc_hw_desc seq[],
185 			unsigned int seq_len)
186 {
187 	int i, w;
188 	void __iomem *reg = drvdata->cc_base + CC_REG(DSCRPTR_QUEUE_WORD0);
189 	struct device *dev = drvdata_to_dev(drvdata);
190 
191 	/*
192 	 * We do indeed write all 6 command words to the same
193 	 * register. The HW supports this.
194 	 */
195 
196 	for (i = 0; i < seq_len; i++) {
197 		for (w = 0; w <= 5; w++)
198 			writel_relaxed(seq[i].word[w], reg);
199 
200 		if (cc_dump_desc)
201 			dev_dbg(dev, "desc[%02d]: 0x%08X 0x%08X 0x%08X 0x%08X 0x%08X 0x%08X\n",
202 				i, seq[i].word[0], seq[i].word[1],
203 				seq[i].word[2], seq[i].word[3],
204 				seq[i].word[4], seq[i].word[5]);
205 	}
206 }
207 
208 /**
209  * request_mgr_complete() - Completion will take place if and only if user
210  * requested completion by cc_send_sync_request().
211  *
212  * @dev: Device pointer
213  * @dx_compl_h: The completion event to signal
214  * @dummy: unused error code
215  */
216 static void request_mgr_complete(struct device *dev, void *dx_compl_h,
217 				 int dummy)
218 {
219 	struct completion *this_compl = dx_compl_h;
220 
221 	complete(this_compl);
222 }
223 
224 static int cc_queues_status(struct cc_drvdata *drvdata,
225 			    struct cc_req_mgr_handle *req_mgr_h,
226 			    unsigned int total_seq_len)
227 {
228 	unsigned long poll_queue;
229 	struct device *dev = drvdata_to_dev(drvdata);
230 
231 	/* SW queue is checked only once as it will not
232 	 * be changed during the poll because the spinlock_bh
233 	 * is held by the thread
234 	 */
235 	if (((req_mgr_h->req_queue_head + 1) & (MAX_REQUEST_QUEUE_SIZE - 1)) ==
236 	    req_mgr_h->req_queue_tail) {
237 		dev_err(dev, "SW FIFO is full. req_queue_head=%d sw_fifo_len=%d\n",
238 			req_mgr_h->req_queue_head, MAX_REQUEST_QUEUE_SIZE);
239 		return -ENOSPC;
240 	}
241 
242 	if (req_mgr_h->q_free_slots >= total_seq_len)
243 		return 0;
244 
245 	/* Wait for space in HW queue. Poll constant num of iterations. */
246 	for (poll_queue = 0; poll_queue < CC_MAX_POLL_ITER ; poll_queue++) {
247 		req_mgr_h->q_free_slots =
248 			cc_ioread(drvdata, CC_REG(DSCRPTR_QUEUE_CONTENT));
249 		if (req_mgr_h->q_free_slots < req_mgr_h->min_free_hw_slots)
250 			req_mgr_h->min_free_hw_slots = req_mgr_h->q_free_slots;
251 
252 		if (req_mgr_h->q_free_slots >= total_seq_len) {
253 			/* If there is enough place return */
254 			return 0;
255 		}
256 
257 		dev_dbg(dev, "HW FIFO is full. q_free_slots=%d total_seq_len=%d\n",
258 			req_mgr_h->q_free_slots, total_seq_len);
259 	}
260 	/* No room in the HW queue try again later */
261 	dev_dbg(dev, "HW FIFO full, timeout. req_queue_head=%d sw_fifo_len=%d q_free_slots=%d total_seq_len=%d\n",
262 		req_mgr_h->req_queue_head, MAX_REQUEST_QUEUE_SIZE,
263 		req_mgr_h->q_free_slots, total_seq_len);
264 	return -ENOSPC;
265 }
266 
267 /**
268  * cc_do_send_request() - Enqueue caller request to crypto hardware.
269  * Need to be called with HW lock held and PM running
270  *
271  * @drvdata: Associated device driver context
272  * @cc_req: The request to enqueue
273  * @desc: The crypto sequence
274  * @len: The crypto sequence length
275  * @add_comp: If "true": add an artificial dout DMA to mark completion
276  *
277  */
278 static void cc_do_send_request(struct cc_drvdata *drvdata,
279 			       struct cc_crypto_req *cc_req,
280 			       struct cc_hw_desc *desc, unsigned int len,
281 			       bool add_comp)
282 {
283 	struct cc_req_mgr_handle *req_mgr_h = drvdata->request_mgr_handle;
284 	unsigned int used_sw_slots;
285 	unsigned int total_seq_len = len; /*initial sequence length*/
286 	struct device *dev = drvdata_to_dev(drvdata);
287 
288 	used_sw_slots = ((req_mgr_h->req_queue_head -
289 			  req_mgr_h->req_queue_tail) &
290 			 (MAX_REQUEST_QUEUE_SIZE - 1));
291 	if (used_sw_slots > req_mgr_h->max_used_sw_slots)
292 		req_mgr_h->max_used_sw_slots = used_sw_slots;
293 
294 	/* Enqueue request - must be locked with HW lock*/
295 	req_mgr_h->req_queue[req_mgr_h->req_queue_head] = *cc_req;
296 	req_mgr_h->req_queue_head = (req_mgr_h->req_queue_head + 1) &
297 				    (MAX_REQUEST_QUEUE_SIZE - 1);
298 
299 	dev_dbg(dev, "Enqueue request head=%u\n", req_mgr_h->req_queue_head);
300 
301 	/*
302 	 * We are about to push command to the HW via the command registers
303 	 * that may reference host memory. We need to issue a memory barrier
304 	 * to make sure there are no outstanding memory writes
305 	 */
306 	wmb();
307 
308 	/* STAT_PHASE_4: Push sequence */
309 
310 	enqueue_seq(drvdata, desc, len);
311 
312 	if (add_comp) {
313 		enqueue_seq(drvdata, &req_mgr_h->compl_desc, 1);
314 		total_seq_len++;
315 	}
316 
317 	if (req_mgr_h->q_free_slots < total_seq_len) {
318 		/* This situation should never occur. Maybe indicating problem
319 		 * with resuming power. Set the free slot count to 0 and hope
320 		 * for the best.
321 		 */
322 		dev_err(dev, "HW free slot count mismatch.");
323 		req_mgr_h->q_free_slots = 0;
324 	} else {
325 		/* Update the free slots in HW queue */
326 		req_mgr_h->q_free_slots -= total_seq_len;
327 	}
328 }
329 
330 static void cc_enqueue_backlog(struct cc_drvdata *drvdata,
331 			       struct cc_bl_item *bli)
332 {
333 	struct cc_req_mgr_handle *mgr = drvdata->request_mgr_handle;
334 	struct device *dev = drvdata_to_dev(drvdata);
335 
336 	spin_lock_bh(&mgr->bl_lock);
337 	list_add_tail(&bli->list, &mgr->backlog);
338 	++mgr->bl_len;
339 	dev_dbg(dev, "+++bl len: %d\n", mgr->bl_len);
340 	spin_unlock_bh(&mgr->bl_lock);
341 	tasklet_schedule(&mgr->comptask);
342 }
343 
344 static void cc_proc_backlog(struct cc_drvdata *drvdata)
345 {
346 	struct cc_req_mgr_handle *mgr = drvdata->request_mgr_handle;
347 	struct cc_bl_item *bli;
348 	struct cc_crypto_req *creq;
349 	void *req;
350 	struct device *dev = drvdata_to_dev(drvdata);
351 	int rc;
352 
353 	spin_lock(&mgr->bl_lock);
354 
355 	while (mgr->bl_len) {
356 		bli = list_first_entry(&mgr->backlog, struct cc_bl_item, list);
357 		dev_dbg(dev, "---bl len: %d\n", mgr->bl_len);
358 
359 		spin_unlock(&mgr->bl_lock);
360 
361 
362 		creq = &bli->creq;
363 		req = creq->user_arg;
364 
365 		/*
366 		 * Notify the request we're moving out of the backlog
367 		 * but only if we haven't done so already.
368 		 */
369 		if (!bli->notif) {
370 			creq->user_cb(dev, req, -EINPROGRESS);
371 			bli->notif = true;
372 		}
373 
374 		spin_lock(&mgr->hw_lock);
375 
376 		rc = cc_queues_status(drvdata, mgr, bli->len);
377 		if (rc) {
378 			/*
379 			 * There is still no room in the FIFO for
380 			 * this request. Bail out. We'll return here
381 			 * on the next completion irq.
382 			 */
383 			spin_unlock(&mgr->hw_lock);
384 			return;
385 		}
386 
387 		cc_do_send_request(drvdata, &bli->creq, bli->desc, bli->len,
388 				   false);
389 		spin_unlock(&mgr->hw_lock);
390 
391 		/* Remove ourselves from the backlog list */
392 		spin_lock(&mgr->bl_lock);
393 		list_del(&bli->list);
394 		--mgr->bl_len;
395 		kfree(bli);
396 	}
397 
398 	spin_unlock(&mgr->bl_lock);
399 }
400 
401 int cc_send_request(struct cc_drvdata *drvdata, struct cc_crypto_req *cc_req,
402 		    struct cc_hw_desc *desc, unsigned int len,
403 		    struct crypto_async_request *req)
404 {
405 	int rc;
406 	struct cc_req_mgr_handle *mgr = drvdata->request_mgr_handle;
407 	struct device *dev = drvdata_to_dev(drvdata);
408 	bool backlog_ok = req->flags & CRYPTO_TFM_REQ_MAY_BACKLOG;
409 	gfp_t flags = cc_gfp_flags(req);
410 	struct cc_bl_item *bli;
411 
412 	rc = cc_pm_get(dev);
413 	if (rc) {
414 		dev_err(dev, "cc_pm_get returned %x\n", rc);
415 		return rc;
416 	}
417 
418 	spin_lock_bh(&mgr->hw_lock);
419 	rc = cc_queues_status(drvdata, mgr, len);
420 
421 #ifdef CC_DEBUG_FORCE_BACKLOG
422 	if (backlog_ok)
423 		rc = -ENOSPC;
424 #endif /* CC_DEBUG_FORCE_BACKLOG */
425 
426 	if (rc == -ENOSPC && backlog_ok) {
427 		spin_unlock_bh(&mgr->hw_lock);
428 
429 		bli = kmalloc(sizeof(*bli), flags);
430 		if (!bli) {
431 			cc_pm_put_suspend(dev);
432 			return -ENOMEM;
433 		}
434 
435 		memcpy(&bli->creq, cc_req, sizeof(*cc_req));
436 		memcpy(&bli->desc, desc, len * sizeof(*desc));
437 		bli->len = len;
438 		bli->notif = false;
439 		cc_enqueue_backlog(drvdata, bli);
440 		return -EBUSY;
441 	}
442 
443 	if (!rc) {
444 		cc_do_send_request(drvdata, cc_req, desc, len, false);
445 		rc = -EINPROGRESS;
446 	}
447 
448 	spin_unlock_bh(&mgr->hw_lock);
449 	return rc;
450 }
451 
452 int cc_send_sync_request(struct cc_drvdata *drvdata,
453 			 struct cc_crypto_req *cc_req, struct cc_hw_desc *desc,
454 			 unsigned int len)
455 {
456 	int rc;
457 	struct device *dev = drvdata_to_dev(drvdata);
458 	struct cc_req_mgr_handle *mgr = drvdata->request_mgr_handle;
459 
460 	init_completion(&cc_req->seq_compl);
461 	cc_req->user_cb = request_mgr_complete;
462 	cc_req->user_arg = &cc_req->seq_compl;
463 
464 	rc = cc_pm_get(dev);
465 	if (rc) {
466 		dev_err(dev, "cc_pm_get returned %x\n", rc);
467 		return rc;
468 	}
469 
470 	while (true) {
471 		spin_lock_bh(&mgr->hw_lock);
472 		rc = cc_queues_status(drvdata, mgr, len + 1);
473 
474 		if (!rc)
475 			break;
476 
477 		spin_unlock_bh(&mgr->hw_lock);
478 		wait_for_completion_interruptible(&drvdata->hw_queue_avail);
479 		reinit_completion(&drvdata->hw_queue_avail);
480 	}
481 
482 	cc_do_send_request(drvdata, cc_req, desc, len, true);
483 	spin_unlock_bh(&mgr->hw_lock);
484 	wait_for_completion(&cc_req->seq_compl);
485 	return 0;
486 }
487 
488 /**
489  * send_request_init() - Enqueue caller request to crypto hardware during init
490  * process.
491  * Assume this function is not called in the middle of a flow,
492  * since we set QUEUE_LAST_IND flag in the last descriptor.
493  *
494  * @drvdata: Associated device driver context
495  * @desc: The crypto sequence
496  * @len: The crypto sequence length
497  *
498  * Return:
499  * Returns "0" upon success
500  */
501 int send_request_init(struct cc_drvdata *drvdata, struct cc_hw_desc *desc,
502 		      unsigned int len)
503 {
504 	struct cc_req_mgr_handle *req_mgr_h = drvdata->request_mgr_handle;
505 	unsigned int total_seq_len = len; /*initial sequence length*/
506 	int rc = 0;
507 
508 	/* Wait for space in HW and SW FIFO. Poll for as much as FIFO_TIMEOUT.
509 	 */
510 	rc = cc_queues_status(drvdata, req_mgr_h, total_seq_len);
511 	if (rc)
512 		return rc;
513 
514 	set_queue_last_ind(drvdata, &desc[(len - 1)]);
515 
516 	/*
517 	 * We are about to push command to the HW via the command registers
518 	 * that may reference host memory. We need to issue a memory barrier
519 	 * to make sure there are no outstanding memory writes
520 	 */
521 	wmb();
522 	enqueue_seq(drvdata, desc, len);
523 
524 	/* Update the free slots in HW queue */
525 	req_mgr_h->q_free_slots =
526 		cc_ioread(drvdata, CC_REG(DSCRPTR_QUEUE_CONTENT));
527 
528 	return 0;
529 }
530 
531 void complete_request(struct cc_drvdata *drvdata)
532 {
533 	struct cc_req_mgr_handle *request_mgr_handle =
534 						drvdata->request_mgr_handle;
535 
536 	complete(&drvdata->hw_queue_avail);
537 #ifdef COMP_IN_WQ
538 	queue_delayed_work(request_mgr_handle->workq,
539 			   &request_mgr_handle->compwork, 0);
540 #else
541 	tasklet_schedule(&request_mgr_handle->comptask);
542 #endif
543 }
544 
545 #ifdef COMP_IN_WQ
546 static void comp_work_handler(struct work_struct *work)
547 {
548 	struct cc_drvdata *drvdata =
549 		container_of(work, struct cc_drvdata, compwork.work);
550 
551 	comp_handler((unsigned long)drvdata);
552 }
553 #endif
554 
555 static void proc_completions(struct cc_drvdata *drvdata)
556 {
557 	struct cc_crypto_req *cc_req;
558 	struct device *dev = drvdata_to_dev(drvdata);
559 	struct cc_req_mgr_handle *request_mgr_handle =
560 						drvdata->request_mgr_handle;
561 	unsigned int *tail = &request_mgr_handle->req_queue_tail;
562 	unsigned int *head = &request_mgr_handle->req_queue_head;
563 	int rc;
564 	u32 mask;
565 
566 	while (request_mgr_handle->axi_completed) {
567 		request_mgr_handle->axi_completed--;
568 
569 		/* Dequeue request */
570 		if (*head == *tail) {
571 			/* We are supposed to handle a completion but our
572 			 * queue is empty. This is not normal. Return and
573 			 * hope for the best.
574 			 */
575 			dev_err(dev, "Request queue is empty head == tail %u\n",
576 				*head);
577 			break;
578 		}
579 
580 		cc_req = &request_mgr_handle->req_queue[*tail];
581 
582 		if (cc_req->cpp.is_cpp) {
583 
584 			dev_dbg(dev, "CPP request completion slot: %d alg:%d\n",
585 				cc_req->cpp.slot, cc_req->cpp.alg);
586 			mask = cc_cpp_int_mask(cc_req->cpp.alg,
587 					       cc_req->cpp.slot);
588 			rc = (drvdata->irq & mask ? -EPERM : 0);
589 			dev_dbg(dev, "Got mask: %x irq: %x rc: %d\n", mask,
590 				drvdata->irq, rc);
591 		} else {
592 			dev_dbg(dev, "None CPP request completion\n");
593 			rc = 0;
594 		}
595 
596 		if (cc_req->user_cb)
597 			cc_req->user_cb(dev, cc_req->user_arg, rc);
598 		*tail = (*tail + 1) & (MAX_REQUEST_QUEUE_SIZE - 1);
599 		dev_dbg(dev, "Dequeue request tail=%u\n", *tail);
600 		dev_dbg(dev, "Request completed. axi_completed=%d\n",
601 			request_mgr_handle->axi_completed);
602 		cc_pm_put_suspend(dev);
603 	}
604 }
605 
606 static inline u32 cc_axi_comp_count(struct cc_drvdata *drvdata)
607 {
608 	return FIELD_GET(AXIM_MON_COMP_VALUE,
609 			 cc_ioread(drvdata, drvdata->axim_mon_offset));
610 }
611 
612 /* Deferred service handler, run as interrupt-fired tasklet */
613 static void comp_handler(unsigned long devarg)
614 {
615 	struct cc_drvdata *drvdata = (struct cc_drvdata *)devarg;
616 	struct cc_req_mgr_handle *request_mgr_handle =
617 						drvdata->request_mgr_handle;
618 	struct device *dev = drvdata_to_dev(drvdata);
619 	u32 irq;
620 
621 	dev_dbg(dev, "Completion handler called!\n");
622 	irq = (drvdata->irq & drvdata->comp_mask);
623 
624 	/* To avoid the interrupt from firing as we unmask it,
625 	 * we clear it now
626 	 */
627 	cc_iowrite(drvdata, CC_REG(HOST_ICR), irq);
628 
629 	/* Avoid race with above clear: Test completion counter once more */
630 
631 	request_mgr_handle->axi_completed += cc_axi_comp_count(drvdata);
632 
633 	dev_dbg(dev, "AXI completion after updated: %d\n",
634 		request_mgr_handle->axi_completed);
635 
636 	while (request_mgr_handle->axi_completed) {
637 		do {
638 			drvdata->irq |= cc_ioread(drvdata, CC_REG(HOST_IRR));
639 			irq = (drvdata->irq & drvdata->comp_mask);
640 			proc_completions(drvdata);
641 
642 			/* At this point (after proc_completions()),
643 			 * request_mgr_handle->axi_completed is 0.
644 			 */
645 			request_mgr_handle->axi_completed +=
646 						cc_axi_comp_count(drvdata);
647 		} while (request_mgr_handle->axi_completed > 0);
648 
649 		cc_iowrite(drvdata, CC_REG(HOST_ICR), irq);
650 
651 		request_mgr_handle->axi_completed += cc_axi_comp_count(drvdata);
652 	}
653 
654 	/* after verifying that there is nothing to do,
655 	 * unmask AXI completion interrupt
656 	 */
657 	cc_iowrite(drvdata, CC_REG(HOST_IMR),
658 		   cc_ioread(drvdata, CC_REG(HOST_IMR)) & ~drvdata->comp_mask);
659 
660 	cc_proc_backlog(drvdata);
661 	dev_dbg(dev, "Comp. handler done.\n");
662 }
663