summaryrefslogtreecommitdiff
path: root/sound/xen/xen_snd_front_evtchnl.c
blob: 26d1b3987887c698f80fb50c1cbc2c56e8b2f6da (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
// SPDX-License-Identifier: GPL-2.0 OR MIT

/*
 * Xen para-virtual sound device
 *
 * Copyright (C) 2016-2018 EPAM Systems Inc.
 *
 * Author: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
 */

#include <xen/events.h>
#include <xen/grant_table.h>
#include <xen/xen.h>
#include <xen/xenbus.h>

#include "xen_snd_front.h"
#include "xen_snd_front_alsa.h"
#include "xen_snd_front_cfg.h"
#include "xen_snd_front_evtchnl.h"

static irqreturn_t evtchnl_interrupt_req(int irq, void *dev_id)
{
	struct xen_snd_front_evtchnl *channel = dev_id;
	struct xen_snd_front_info *front_info = channel->front_info;
	struct xensnd_resp *resp;
	RING_IDX i, rp;

	if (unlikely(channel->state != EVTCHNL_STATE_CONNECTED))
		return IRQ_HANDLED;

	mutex_lock(&channel->ring_io_lock);

again:
	rp = channel->u.req.ring.sring->rsp_prod;
	/* Ensure we see queued responses up to rp. */
	rmb();

	/*
	 * Assume that the backend is trusted to always write sane values
	 * to the ring counters, so no overflow checks on frontend side
	 * are required.
	 */
	for (i = channel->u.req.ring.rsp_cons; i != rp; i++) {
		resp = RING_GET_RESPONSE(&channel->u.req.ring, i);
		if (resp->id != channel->evt_id)
			continue;
		switch (resp->operation) {
		case XENSND_OP_OPEN:
		case XENSND_OP_CLOSE:
		case XENSND_OP_READ:
		case XENSND_OP_WRITE:
		case XENSND_OP_TRIGGER:
			channel->u.req.resp_status = resp->status;
			complete(&channel->u.req.completion);
			break;
		case XENSND_OP_HW_PARAM_QUERY:
			channel->u.req.resp_status = resp->status;
			channel->u.req.resp.hw_param =
					resp->resp.hw_param;
			complete(&channel->u.req.completion);
			break;

		default:
			dev_err(&front_info->xb_dev->dev,
				"Operation %d is not supported\n",
				resp->operation);
			break;
		}
	}

	channel->u.req.ring.rsp_cons = i;
	if (i != channel->u.req.ring.req_prod_pvt) {
		int more_to_do;

		RING_FINAL_CHECK_FOR_RESPONSES(&channel->u.req.ring,
					       more_to_do);
		if (more_to_do)
			goto again;
	} else {
		channel->u.req.ring.sring->rsp_event = i + 1;
	}

	mutex_unlock(&channel->ring_io_lock);
	return IRQ_HANDLED;
}

static irqreturn_t evtchnl_interrupt_evt(int irq, void *dev_id)
{
	struct xen_snd_front_evtchnl *channel = dev_id;
	struct xensnd_event_page *page = channel->u.evt.page;
	u32 cons, prod;

	if (unlikely(channel->state != EVTCHNL_STATE_CONNECTED))
		return IRQ_HANDLED;

	mutex_lock(&channel->ring_io_lock);

	prod = page->in_prod;
	/* Ensure we see ring contents up to prod. */
	virt_rmb();
	if (prod == page->in_cons)
		goto out;

	/*
	 * Assume that the backend is trusted to always write sane values
	 * to the ring counters, so no overflow checks on frontend side
	 * are required.
	 */
	for (cons = page->in_cons; cons != prod; cons++) {
		struct xensnd_evt *event;

		event = &XENSND_IN_RING_REF(page, cons);
		if (unlikely(event->id != channel->evt_id++))
			continue;

		switch (event->type) {
		case XENSND_EVT_CUR_POS:
			xen_snd_front_alsa_handle_cur_pos(channel,
							  event->op.cur_pos.position);
			break;
		}
	}

	page->in_cons = cons;
	/* Ensure ring contents. */
	virt_wmb();

out:
	mutex_unlock(&channel->ring_io_lock);
	return IRQ_HANDLED;
}

void xen_snd_front_evtchnl_flush(struct xen_snd_front_evtchnl *channel)
{
	int notify;

	channel->u.req.ring.req_prod_pvt++;
	RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&channel->u.req.ring, notify);
	if (notify)
		notify_remote_via_irq(channel->irq);
}

static void evtchnl_free(struct xen_snd_front_info *front_info,
			 struct xen_snd_front_evtchnl *channel)
{
	void *page = NULL;

	if (channel->type == EVTCHNL_TYPE_REQ)
		page = channel->u.req.ring.sring;
	else if (channel->type == EVTCHNL_TYPE_EVT)
		page = channel->u.evt.page;

	if (!page)
		return;

	channel->state = EVTCHNL_STATE_DISCONNECTED;
	if (channel->type == EVTCHNL_TYPE_REQ) {
		/* Release all who still waits for response if any. */
		channel->u.req.resp_status = -EIO;
		complete_all(&channel->u.req.completion);
	}

	if (channel->irq)
		unbind_from_irqhandler(channel->irq, channel);

	if (channel->port)
		xenbus_free_evtchn(front_info->xb_dev, channel->port);

	/* End access and free the page. */
	xenbus_teardown_ring(&page, 1, &channel->gref);

	memset(channel, 0, sizeof(*channel));
}

void xen_snd_front_evtchnl_free_all(struct xen_snd_front_info *front_info)
{
	int i;

	if (!front_info->evt_pairs)
		return;

	for (i = 0; i < front_info->num_evt_pairs; i++) {
		evtchnl_free(front_info, &front_info->evt_pairs[i].req);
		evtchnl_free(front_info, &front_info->evt_pairs[i].evt);
	}

	kfree(front_info->evt_pairs);
	front_info->evt_pairs = NULL;
}

static int evtchnl_alloc(struct xen_snd_front_info *front_info, int index,
			 struct xen_snd_front_evtchnl *channel,
			 enum xen_snd_front_evtchnl_type type)
{
	struct xenbus_device *xb_dev = front_info->xb_dev;
	void *page;
	irq_handler_t handler;
	char *handler_name = NULL;
	int ret;

	memset(channel, 0, sizeof(*channel));
	channel->type = type;
	channel->index = index;
	channel->front_info = front_info;
	channel->state = EVTCHNL_STATE_DISCONNECTED;
	ret = xenbus_setup_ring(xb_dev, GFP_KERNEL, &page, 1, &channel->gref);
	if (ret)
		goto fail;

	handler_name = kasprintf(GFP_KERNEL, "%s-%s", XENSND_DRIVER_NAME,
				 type == EVTCHNL_TYPE_REQ ?
				 XENSND_FIELD_RING_REF :
				 XENSND_FIELD_EVT_RING_REF);
	if (!handler_name) {
		ret = -ENOMEM;
		goto fail;
	}

	mutex_init(&channel->ring_io_lock);

	if (type == EVTCHNL_TYPE_REQ) {
		struct xen_sndif_sring *sring = page;

		init_completion(&channel->u.req.completion);
		mutex_init(&channel->u.req.req_io_lock);
		XEN_FRONT_RING_INIT(&channel->u.req.ring, sring, XEN_PAGE_SIZE);

		handler = evtchnl_interrupt_req;
	} else {
		channel->u.evt.page = page;
		handler = evtchnl_interrupt_evt;
	}

	ret = xenbus_alloc_evtchn(xb_dev, &channel->port);
	if (ret < 0)
		goto fail;

	ret = bind_evtchn_to_irq(channel->port);
	if (ret < 0) {
		dev_err(&xb_dev->dev,
			"Failed to bind IRQ for domid %d port %d: %d\n",
			front_info->xb_dev->otherend_id, channel->port, ret);
		goto fail;
	}

	channel->irq = ret;

	ret = request_threaded_irq(channel->irq, NULL, handler,
				   IRQF_ONESHOT, handler_name, channel);
	if (ret < 0) {
		dev_err(&xb_dev->dev, "Failed to request IRQ %d: %d\n",
			channel->irq, ret);
		goto fail;
	}

	kfree(handler_name);
	return 0;

fail:
	kfree(handler_name);
	dev_err(&xb_dev->dev, "Failed to allocate ring: %d\n", ret);
	return ret;
}

int xen_snd_front_evtchnl_create_all(struct xen_snd_front_info *front_info,
				     int num_streams)
{
	struct xen_front_cfg_card *cfg = &front_info->cfg;
	struct device *dev = &front_info->xb_dev->dev;
	int d, ret = 0;

	front_info->evt_pairs =
			kcalloc(num_streams,
				sizeof(struct xen_snd_front_evtchnl_pair),
				GFP_KERNEL);
	if (!front_info->evt_pairs)
		return -ENOMEM;

	/* Iterate over devices and their streams and create event channels. */
	for (d = 0; d < cfg->num_pcm_instances; d++) {
		struct xen_front_cfg_pcm_instance *pcm_instance;
		int s, index;

		pcm_instance = &cfg->pcm_instances[d];

		for (s = 0; s < pcm_instance->num_streams_pb; s++) {
			index = pcm_instance->streams_pb[s].index;

			ret = evtchnl_alloc(front_info, index,
					    &front_info->evt_pairs[index].req,
					    EVTCHNL_TYPE_REQ);
			if (ret < 0) {
				dev_err(dev, "Error allocating control channel\n");
				goto fail;
			}

			ret = evtchnl_alloc(front_info, index,
					    &front_info->evt_pairs[index].evt,
					    EVTCHNL_TYPE_EVT);
			if (ret < 0) {
				dev_err(dev, "Error allocating in-event channel\n");
				goto fail;
			}
		}

		for (s = 0; s < pcm_instance->num_streams_cap; s++) {
			index = pcm_instance->streams_cap[s].index;

			ret = evtchnl_alloc(front_info, index,
					    &front_info->evt_pairs[index].req,
					    EVTCHNL_TYPE_REQ);
			if (ret < 0) {
				dev_err(dev, "Error allocating control channel\n");
				goto fail;
			}

			ret = evtchnl_alloc(front_info, index,
					    &front_info->evt_pairs[index].evt,
					    EVTCHNL_TYPE_EVT);
			if (ret < 0) {
				dev_err(dev, "Error allocating in-event channel\n");
				goto fail;
			}
		}
	}

	front_info->num_evt_pairs = num_streams;
	return 0;

fail:
	xen_snd_front_evtchnl_free_all(front_info);
	return ret;
}

static int evtchnl_publish(struct xenbus_transaction xbt,
			   struct xen_snd_front_evtchnl *channel,
			   const char *path, const char *node_ring,
			   const char *node_chnl)
{
	struct xenbus_device *xb_dev = channel->front_info->xb_dev;
	int ret;

	/* Write control channel ring reference. */
	ret = xenbus_printf(xbt, path, node_ring, "%u", channel->gref);
	if (ret < 0) {
		dev_err(&xb_dev->dev, "Error writing ring-ref: %d\n", ret);
		return ret;
	}

	/* Write event channel ring reference. */
	ret = xenbus_printf(xbt, path, node_chnl, "%u", channel->port);
	if (ret < 0) {
		dev_err(&xb_dev->dev, "Error writing event channel: %d\n", ret);
		return ret;
	}

	return 0;
}

int xen_snd_front_evtchnl_publish_all(struct xen_snd_front_info *front_info)
{
	struct xen_front_cfg_card *cfg = &front_info->cfg;
	struct xenbus_transaction xbt;
	int ret, d;

again:
	ret = xenbus_transaction_start(&xbt);
	if (ret < 0) {
		xenbus_dev_fatal(front_info->xb_dev, ret,
				 "starting transaction");
		return ret;
	}

	for (d = 0; d < cfg->num_pcm_instances; d++) {
		struct xen_front_cfg_pcm_instance *pcm_instance;
		int s, index;

		pcm_instance = &cfg->pcm_instances[d];

		for (s = 0; s < pcm_instance->num_streams_pb; s++) {
			index = pcm_instance->streams_pb[s].index;

			ret = evtchnl_publish(xbt,
					      &front_info->evt_pairs[index].req,
					      pcm_instance->streams_pb[s].xenstore_path,
					      XENSND_FIELD_RING_REF,
					      XENSND_FIELD_EVT_CHNL);
			if (ret < 0)
				goto fail;

			ret = evtchnl_publish(xbt,
					      &front_info->evt_pairs[index].evt,
					      pcm_instance->streams_pb[s].xenstore_path,
					      XENSND_FIELD_EVT_RING_REF,
					      XENSND_FIELD_EVT_EVT_CHNL);
			if (ret < 0)
				goto fail;
		}

		for (s = 0; s < pcm_instance->num_streams_cap; s++) {
			index = pcm_instance->streams_cap[s].index;

			ret = evtchnl_publish(xbt,
					      &front_info->evt_pairs[index].req,
					      pcm_instance->streams_cap[s].xenstore_path,
					      XENSND_FIELD_RING_REF,
					      XENSND_FIELD_EVT_CHNL);
			if (ret < 0)
				goto fail;

			ret = evtchnl_publish(xbt,
					      &front_info->evt_pairs[index].evt,
					      pcm_instance->streams_cap[s].xenstore_path,
					      XENSND_FIELD_EVT_RING_REF,
					      XENSND_FIELD_EVT_EVT_CHNL);
			if (ret < 0)
				goto fail;
		}
	}
	ret = xenbus_transaction_end(xbt, 0);
	if (ret < 0) {
		if (ret == -EAGAIN)
			goto again;

		xenbus_dev_fatal(front_info->xb_dev, ret,
				 "completing transaction");
		goto fail_to_end;
	}
	return 0;
fail:
	xenbus_transaction_end(xbt, 1);
fail_to_end:
	xenbus_dev_fatal(front_info->xb_dev, ret, "writing XenStore");
	return ret;
}

void xen_snd_front_evtchnl_pair_set_connected(struct xen_snd_front_evtchnl_pair *evt_pair,
					      bool is_connected)
{
	enum xen_snd_front_evtchnl_state state;

	if (is_connected)
		state = EVTCHNL_STATE_CONNECTED;
	else
		state = EVTCHNL_STATE_DISCONNECTED;

	mutex_lock(&evt_pair->req.ring_io_lock);
	evt_pair->req.state = state;
	mutex_unlock(&evt_pair->req.ring_io_lock);

	mutex_lock(&evt_pair->evt.ring_io_lock);
	evt_pair->evt.state = state;
	mutex_unlock(&evt_pair->evt.ring_io_lock);
}

void xen_snd_front_evtchnl_pair_clear(struct xen_snd_front_evtchnl_pair *evt_pair)
{
	mutex_lock(&evt_pair->req.ring_io_lock);
	evt_pair->req.evt_next_id = 0;
	mutex_unlock(&evt_pair->req.ring_io_lock);

	mutex_lock(&evt_pair->evt.ring_io_lock);
	evt_pair->evt.evt_next_id = 0;
	mutex_unlock(&evt_pair->evt.ring_io_lock);
}