summaryrefslogtreecommitdiff
path: root/sound/xen/xen_snd_front.c
blob: 4041748c12e515c090b62f9918a0877ccd0d574c (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
// 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 <linux/delay.h>
#include <linux/module.h>

#include <xen/page.h>
#include <xen/platform_pci.h>
#include <xen/xen.h>
#include <xen/xenbus.h>

#include <xen/xen-front-pgdir-shbuf.h>
#include <xen/interface/io/sndif.h>

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

static struct xensnd_req *
be_stream_prepare_req(struct xen_snd_front_evtchnl *evtchnl, u8 operation)
{
	struct xensnd_req *req;

	req = RING_GET_REQUEST(&evtchnl->u.req.ring,
			       evtchnl->u.req.ring.req_prod_pvt);
	req->operation = operation;
	req->id = evtchnl->evt_next_id++;
	evtchnl->evt_id = req->id;
	return req;
}

static int be_stream_do_io(struct xen_snd_front_evtchnl *evtchnl)
{
	if (unlikely(evtchnl->state != EVTCHNL_STATE_CONNECTED))
		return -EIO;

	reinit_completion(&evtchnl->u.req.completion);
	xen_snd_front_evtchnl_flush(evtchnl);
	return 0;
}

static int be_stream_wait_io(struct xen_snd_front_evtchnl *evtchnl)
{
	if (wait_for_completion_timeout(&evtchnl->u.req.completion,
			msecs_to_jiffies(VSND_WAIT_BACK_MS)) <= 0)
		return -ETIMEDOUT;

	return evtchnl->u.req.resp_status;
}

int xen_snd_front_stream_query_hw_param(struct xen_snd_front_evtchnl *evtchnl,
					struct xensnd_query_hw_param *hw_param_req,
					struct xensnd_query_hw_param *hw_param_resp)
{
	struct xensnd_req *req;
	int ret;

	mutex_lock(&evtchnl->u.req.req_io_lock);

	mutex_lock(&evtchnl->ring_io_lock);
	req = be_stream_prepare_req(evtchnl, XENSND_OP_HW_PARAM_QUERY);
	req->op.hw_param = *hw_param_req;
	mutex_unlock(&evtchnl->ring_io_lock);

	ret = be_stream_do_io(evtchnl);

	if (ret == 0)
		ret = be_stream_wait_io(evtchnl);

	if (ret == 0)
		*hw_param_resp = evtchnl->u.req.resp.hw_param;

	mutex_unlock(&evtchnl->u.req.req_io_lock);
	return ret;
}

int xen_snd_front_stream_prepare(struct xen_snd_front_evtchnl *evtchnl,
				 struct xen_front_pgdir_shbuf *shbuf,
				 u8 format, unsigned int channels,
				 unsigned int rate, u32 buffer_sz,
				 u32 period_sz)
{
	struct xensnd_req *req;
	int ret;

	mutex_lock(&evtchnl->u.req.req_io_lock);

	mutex_lock(&evtchnl->ring_io_lock);
	req = be_stream_prepare_req(evtchnl, XENSND_OP_OPEN);
	req->op.open.pcm_format = format;
	req->op.open.pcm_channels = channels;
	req->op.open.pcm_rate = rate;
	req->op.open.buffer_sz = buffer_sz;
	req->op.open.period_sz = period_sz;
	req->op.open.gref_directory =
		xen_front_pgdir_shbuf_get_dir_start(shbuf);
	mutex_unlock(&evtchnl->ring_io_lock);

	ret = be_stream_do_io(evtchnl);

	if (ret == 0)
		ret = be_stream_wait_io(evtchnl);

	mutex_unlock(&evtchnl->u.req.req_io_lock);
	return ret;
}

int xen_snd_front_stream_close(struct xen_snd_front_evtchnl *evtchnl)
{
	__always_unused struct xensnd_req *req;
	int ret;

	mutex_lock(&evtchnl->u.req.req_io_lock);

	mutex_lock(&evtchnl->ring_io_lock);
	req = be_stream_prepare_req(evtchnl, XENSND_OP_CLOSE);
	mutex_unlock(&evtchnl->ring_io_lock);

	ret = be_stream_do_io(evtchnl);

	if (ret == 0)
		ret = be_stream_wait_io(evtchnl);

	mutex_unlock(&evtchnl->u.req.req_io_lock);
	return ret;
}

int xen_snd_front_stream_write(struct xen_snd_front_evtchnl *evtchnl,
			       unsigned long pos, unsigned long count)
{
	struct xensnd_req *req;
	int ret;

	mutex_lock(&evtchnl->u.req.req_io_lock);

	mutex_lock(&evtchnl->ring_io_lock);
	req = be_stream_prepare_req(evtchnl, XENSND_OP_WRITE);
	req->op.rw.length = count;
	req->op.rw.offset = pos;
	mutex_unlock(&evtchnl->ring_io_lock);

	ret = be_stream_do_io(evtchnl);

	if (ret == 0)
		ret = be_stream_wait_io(evtchnl);

	mutex_unlock(&evtchnl->u.req.req_io_lock);
	return ret;
}

int xen_snd_front_stream_read(struct xen_snd_front_evtchnl *evtchnl,
			      unsigned long pos, unsigned long count)
{
	struct xensnd_req *req;
	int ret;

	mutex_lock(&evtchnl->u.req.req_io_lock);

	mutex_lock(&evtchnl->ring_io_lock);
	req = be_stream_prepare_req(evtchnl, XENSND_OP_READ);
	req->op.rw.length = count;
	req->op.rw.offset = pos;
	mutex_unlock(&evtchnl->ring_io_lock);

	ret = be_stream_do_io(evtchnl);

	if (ret == 0)
		ret = be_stream_wait_io(evtchnl);

	mutex_unlock(&evtchnl->u.req.req_io_lock);
	return ret;
}

int xen_snd_front_stream_trigger(struct xen_snd_front_evtchnl *evtchnl,
				 int type)
{
	struct xensnd_req *req;
	int ret;

	mutex_lock(&evtchnl->u.req.req_io_lock);

	mutex_lock(&evtchnl->ring_io_lock);
	req = be_stream_prepare_req(evtchnl, XENSND_OP_TRIGGER);
	req->op.trigger.type = type;
	mutex_unlock(&evtchnl->ring_io_lock);

	ret = be_stream_do_io(evtchnl);

	if (ret == 0)
		ret = be_stream_wait_io(evtchnl);

	mutex_unlock(&evtchnl->u.req.req_io_lock);
	return ret;
}

static void xen_snd_drv_fini(struct xen_snd_front_info *front_info)
{
	xen_snd_front_alsa_fini(front_info);
	xen_snd_front_evtchnl_free_all(front_info);
}

static int sndback_initwait(struct xen_snd_front_info *front_info)
{
	int num_streams;
	int ret;

	ret = xen_snd_front_cfg_card(front_info, &num_streams);
	if (ret < 0)
		return ret;

	/* create event channels for all streams and publish */
	ret = xen_snd_front_evtchnl_create_all(front_info, num_streams);
	if (ret < 0)
		return ret;

	return xen_snd_front_evtchnl_publish_all(front_info);
}

static int sndback_connect(struct xen_snd_front_info *front_info)
{
	return xen_snd_front_alsa_init(front_info);
}

static void sndback_disconnect(struct xen_snd_front_info *front_info)
{
	xen_snd_drv_fini(front_info);
	xenbus_switch_state(front_info->xb_dev, XenbusStateInitialising);
}

static void sndback_changed(struct xenbus_device *xb_dev,
			    enum xenbus_state backend_state)
{
	struct xen_snd_front_info *front_info = dev_get_drvdata(&xb_dev->dev);
	int ret;

	dev_dbg(&xb_dev->dev, "Backend state is %s, front is %s\n",
		xenbus_strstate(backend_state),
		xenbus_strstate(xb_dev->state));

	switch (backend_state) {
	case XenbusStateReconfiguring:
	case XenbusStateReconfigured:
	case XenbusStateInitialised:
		break;

	case XenbusStateInitialising:
		/* Recovering after backend unexpected closure. */
		sndback_disconnect(front_info);
		break;

	case XenbusStateInitWait:
		/* Recovering after backend unexpected closure. */
		sndback_disconnect(front_info);

		ret = sndback_initwait(front_info);
		if (ret < 0)
			xenbus_dev_fatal(xb_dev, ret, "initializing frontend");
		else
			xenbus_switch_state(xb_dev, XenbusStateInitialised);
		break;

	case XenbusStateConnected:
		if (xb_dev->state != XenbusStateInitialised)
			break;

		ret = sndback_connect(front_info);
		if (ret < 0)
			xenbus_dev_fatal(xb_dev, ret, "initializing frontend");
		else
			xenbus_switch_state(xb_dev, XenbusStateConnected);
		break;

	case XenbusStateClosing:
		/*
		 * In this state backend starts freeing resources,
		 * so let it go into closed state first, so we can also
		 * remove ours.
		 */
		break;

	case XenbusStateUnknown:
	case XenbusStateClosed:
		if (xb_dev->state == XenbusStateClosed)
			break;

		sndback_disconnect(front_info);
		break;
	}
}

static int xen_drv_probe(struct xenbus_device *xb_dev,
			 const struct xenbus_device_id *id)
{
	struct xen_snd_front_info *front_info;

	front_info = devm_kzalloc(&xb_dev->dev,
				  sizeof(*front_info), GFP_KERNEL);
	if (!front_info)
		return -ENOMEM;

	front_info->xb_dev = xb_dev;
	dev_set_drvdata(&xb_dev->dev, front_info);

	return xenbus_switch_state(xb_dev, XenbusStateInitialising);
}

static int xen_drv_remove(struct xenbus_device *dev)
{
	struct xen_snd_front_info *front_info = dev_get_drvdata(&dev->dev);
	int to = 100;

	xenbus_switch_state(dev, XenbusStateClosing);

	/*
	 * On driver removal it is disconnected from XenBus,
	 * so no backend state change events come via .otherend_changed
	 * callback. This prevents us from exiting gracefully, e.g.
	 * signaling the backend to free event channels, waiting for its
	 * state to change to XenbusStateClosed and cleaning at our end.
	 * Normally when front driver removed backend will finally go into
	 * XenbusStateInitWait state.
	 *
	 * Workaround: read backend's state manually and wait with time-out.
	 */
	while ((xenbus_read_unsigned(front_info->xb_dev->otherend, "state",
				     XenbusStateUnknown) != XenbusStateInitWait) &&
	       --to)
		msleep(10);

	if (!to) {
		unsigned int state;

		state = xenbus_read_unsigned(front_info->xb_dev->otherend,
					     "state", XenbusStateUnknown);
		pr_err("Backend state is %s while removing driver\n",
		       xenbus_strstate(state));
	}

	xen_snd_drv_fini(front_info);
	xenbus_frontend_closed(dev);
	return 0;
}

static const struct xenbus_device_id xen_drv_ids[] = {
	{ XENSND_DRIVER_NAME },
	{ "" }
};

static struct xenbus_driver xen_driver = {
	.ids = xen_drv_ids,
	.probe = xen_drv_probe,
	.remove = xen_drv_remove,
	.otherend_changed = sndback_changed,
	.not_essential = true,
};

static int __init xen_drv_init(void)
{
	if (!xen_domain())
		return -ENODEV;

	if (!xen_has_pv_devices())
		return -ENODEV;

	/* At the moment we only support case with XEN_PAGE_SIZE == PAGE_SIZE */
	if (XEN_PAGE_SIZE != PAGE_SIZE) {
		pr_err(XENSND_DRIVER_NAME ": different kernel and Xen page sizes are not supported: XEN_PAGE_SIZE (%lu) != PAGE_SIZE (%lu)\n",
		       XEN_PAGE_SIZE, PAGE_SIZE);
		return -ENODEV;
	}

	pr_info("Initialising Xen " XENSND_DRIVER_NAME " frontend driver\n");
	return xenbus_register_frontend(&xen_driver);
}

static void __exit xen_drv_fini(void)
{
	pr_info("Unregistering Xen " XENSND_DRIVER_NAME " frontend driver\n");
	xenbus_unregister_driver(&xen_driver);
}

module_init(xen_drv_init);
module_exit(xen_drv_fini);

MODULE_DESCRIPTION("Xen virtual sound device frontend");
MODULE_LICENSE("GPL");
MODULE_ALIAS("xen:" XENSND_DRIVER_NAME);