virtio_card.c

  1// SPDX-License-Identifier: GPL-2.0+
  2/*
  3 * virtio-snd: Virtio sound device
  4 * Copyright (C) 2021 OpenSynergy GmbH
  5 */
  6#include <linux/module.h>
  7#include <linux/moduleparam.h>
  8#include <linux/virtio_config.h>
  9#include <sound/initval.h>
 10#include <uapi/linux/virtio_ids.h>
 11
 12#include "virtio_card.h"
 13
 14u32 virtsnd_msg_timeout_ms = MSEC_PER_SEC;
 15module_param_named(msg_timeout_ms, virtsnd_msg_timeout_ms, uint, 0644);
 16MODULE_PARM_DESC(msg_timeout_ms, "Message completion timeout in milliseconds");
 17
 18static void virtsnd_remove(struct virtio_device *vdev);
 19
 20/**
 21 * virtsnd_event_send() - Add an event to the event queue.
 22 * @vqueue: Underlying event virtqueue.
 23 * @event: Event.
 24 * @notify: Indicates whether or not to send a notification to the device.
 25 * @gfp: Kernel flags for memory allocation.
 26 *
 27 * Context: Any context.
 28 */
 29static void virtsnd_event_send(struct virtqueue *vqueue,
 30			       struct virtio_snd_event *event, bool notify,
 31			       gfp_t gfp)
 32{
 33	struct scatterlist sg;
 34	struct scatterlist *psgs[1] = { &sg };
 35
 36	/* reset event content */
 37	memset(event, 0, sizeof(*event));
 38
 39	sg_init_one(&sg, event, sizeof(*event));
 40
 41	if (virtqueue_add_sgs(vqueue, psgs, 0, 1, event, gfp) || !notify)
 42		return;
 43
 44	if (virtqueue_kick_prepare(vqueue))
 45		virtqueue_notify(vqueue);
 46}
 47
 48/**
 49 * virtsnd_event_dispatch() - Dispatch an event from the device side.
 50 * @snd: VirtIO sound device.
 51 * @event: VirtIO sound event.
 52 *
 53 * Context: Any context.
 54 */
 55static void virtsnd_event_dispatch(struct virtio_snd *snd,
 56				   struct virtio_snd_event *event)
 57{
 58	switch (le32_to_cpu(event->hdr.code)) {
 59	case VIRTIO_SND_EVT_JACK_CONNECTED:
 60	case VIRTIO_SND_EVT_JACK_DISCONNECTED:
 61		virtsnd_jack_event(snd, event);
 62		break;
 63	case VIRTIO_SND_EVT_PCM_PERIOD_ELAPSED:
 64	case VIRTIO_SND_EVT_PCM_XRUN:
 65		virtsnd_pcm_event(snd, event);
 66		break;
 67	case VIRTIO_SND_EVT_CTL_NOTIFY:
 68		virtsnd_kctl_event(snd, event);
 69		break;
 70	}
 71}
 72
 73/**
 74 * virtsnd_event_notify_cb() - Dispatch all reported events from the event queue.
 75 * @vqueue: Underlying event virtqueue.
 76 *
 77 * This callback function is called upon a vring interrupt request from the
 78 * device.
 79 *
 80 * Context: Interrupt context.
 81 */
 82static void virtsnd_event_notify_cb(struct virtqueue *vqueue)
 83{
 84	struct virtio_snd *snd = vqueue->vdev->priv;
 85	struct virtio_snd_queue *queue = virtsnd_event_queue(snd);
 86	struct virtio_snd_event *event;
 87	u32 length;
 88
 89	guard(spinlock_irqsave)(&queue->lock);
 90	do {
 91		virtqueue_disable_cb(vqueue);
 92		while ((event = virtqueue_get_buf(vqueue, &length))) {
 93			virtsnd_event_dispatch(snd, event);
 94			virtsnd_event_send(vqueue, event, true, GFP_ATOMIC);
 95		}
 96	} while (!virtqueue_enable_cb(vqueue));
 97}
 98
 99/**
100 * virtsnd_find_vqs() - Enumerate and initialize all virtqueues.
101 * @snd: VirtIO sound device.
102 *
103 * After calling this function, the event queue is disabled.
104 *
105 * Context: Any context.
106 * Return: 0 on success, -errno on failure.
107 */
108static int virtsnd_find_vqs(struct virtio_snd *snd)
109{
110	struct virtio_device *vdev = snd->vdev;
111	struct virtqueue_info vqs_info[VIRTIO_SND_VQ_MAX] = {
112		[VIRTIO_SND_VQ_CONTROL] = { "virtsnd-ctl",
113					    virtsnd_ctl_notify_cb },
114		[VIRTIO_SND_VQ_EVENT] = { "virtsnd-event",
115					  virtsnd_event_notify_cb },
116		[VIRTIO_SND_VQ_TX] = { "virtsnd-tx",
117				       virtsnd_pcm_tx_notify_cb },
118		[VIRTIO_SND_VQ_RX] = { "virtsnd-rx",
119				       virtsnd_pcm_rx_notify_cb },
120	};
121	struct virtqueue *vqs[VIRTIO_SND_VQ_MAX] = { 0 };
122	unsigned int i;
123	unsigned int n;
124	int rc;
125
126	rc = virtio_find_vqs(vdev, VIRTIO_SND_VQ_MAX, vqs, vqs_info, NULL);
127	if (rc) {
128		dev_err(&vdev->dev, "failed to initialize virtqueues\n");
129		return rc;
130	}
131
132	for (i = 0; i < VIRTIO_SND_VQ_MAX; ++i)
133		snd->queues[i].vqueue = vqs[i];
134
135	/* Allocate events and populate the event queue */
136	virtqueue_disable_cb(vqs[VIRTIO_SND_VQ_EVENT]);
137
138	n = virtqueue_get_vring_size(vqs[VIRTIO_SND_VQ_EVENT]);
139
140	snd->event_msgs = kmalloc_array(n, sizeof(*snd->event_msgs),
141					GFP_KERNEL);
142	if (!snd->event_msgs)
143		return -ENOMEM;
144
145	for (i = 0; i < n; ++i)
146		virtsnd_event_send(vqs[VIRTIO_SND_VQ_EVENT],
147				   &snd->event_msgs[i], false, GFP_KERNEL);
148
149	return 0;
150}
151
152/**
153 * virtsnd_enable_event_vq() - Enable the event virtqueue.
154 * @snd: VirtIO sound device.
155 *
156 * Context: Any context.
157 */
158static void virtsnd_enable_event_vq(struct virtio_snd *snd)
159{
160	struct virtio_snd_queue *queue = virtsnd_event_queue(snd);
161
162	if (!virtqueue_enable_cb(queue->vqueue))
163		virtsnd_event_notify_cb(queue->vqueue);
164}
165
166/**
167 * virtsnd_disable_event_vq() - Disable the event virtqueue.
168 * @snd: VirtIO sound device.
169 *
170 * Context: Any context.
171 */
172static void virtsnd_disable_event_vq(struct virtio_snd *snd)
173{
174	struct virtio_snd_queue *queue = virtsnd_event_queue(snd);
175	struct virtio_snd_event *event;
176	u32 length;
177
178	if (queue->vqueue) {
179		guard(spinlock_irqsave)(&queue->lock);
180		virtqueue_disable_cb(queue->vqueue);
181		while ((event = virtqueue_get_buf(queue->vqueue, &length)))
182			virtsnd_event_dispatch(snd, event);
183	}
184}
185
186/**
187 * virtsnd_build_devs() - Read configuration and build ALSA devices.
188 * @snd: VirtIO sound device.
189 *
190 * Context: Any context that permits to sleep.
191 * Return: 0 on success, -errno on failure.
192 */
193static int virtsnd_build_devs(struct virtio_snd *snd)
194{
195	struct virtio_device *vdev = snd->vdev;
196	struct device *dev = &vdev->dev;
197	int rc;
198
199	rc = snd_card_new(dev, SNDRV_DEFAULT_IDX1, SNDRV_DEFAULT_STR1,
200			  THIS_MODULE, 0, &snd->card);
201	if (rc < 0)
202		return rc;
203
204	snd->card->private_data = snd;
205
206	strscpy(snd->card->driver, VIRTIO_SND_CARD_DRIVER,
207		sizeof(snd->card->driver));
208	strscpy(snd->card->shortname, VIRTIO_SND_CARD_NAME,
209		sizeof(snd->card->shortname));
210	if (dev->parent->bus)
211		snprintf(snd->card->longname, sizeof(snd->card->longname),
212			 VIRTIO_SND_CARD_NAME " at %s/%s/%s",
213			 dev->parent->bus->name, dev_name(dev->parent),
214			 dev_name(dev));
215	else
216		snprintf(snd->card->longname, sizeof(snd->card->longname),
217			 VIRTIO_SND_CARD_NAME " at %s/%s",
218			 dev_name(dev->parent), dev_name(dev));
219
220	rc = virtsnd_jack_parse_cfg(snd);
221	if (rc)
222		return rc;
223
224	rc = virtsnd_pcm_parse_cfg(snd);
225	if (rc)
226		return rc;
227
228	rc = virtsnd_chmap_parse_cfg(snd);
229	if (rc)
230		return rc;
231
232	if (virtio_has_feature(vdev, VIRTIO_SND_F_CTLS)) {
233		rc = virtsnd_kctl_parse_cfg(snd);
234		if (rc)
235			return rc;
236	}
237
238	if (snd->njacks) {
239		rc = virtsnd_jack_build_devs(snd);
240		if (rc)
241			return rc;
242	}
243
244	if (snd->nsubstreams) {
245		rc = virtsnd_pcm_build_devs(snd);
246		if (rc)
247			return rc;
248	}
249
250	if (snd->nchmaps) {
251		rc = virtsnd_chmap_build_devs(snd);
252		if (rc)
253			return rc;
254	}
255
256	if (snd->nkctls) {
257		rc = virtsnd_kctl_build_devs(snd);
258		if (rc)
259			return rc;
260	}
261
262	return snd_card_register(snd->card);
263}
264
265/**
266 * virtsnd_validate() - Validate if the device can be started.
267 * @vdev: VirtIO parent device.
268 *
269 * Context: Any context.
270 * Return: 0 on success, -EINVAL on failure.
271 */
272static int virtsnd_validate(struct virtio_device *vdev)
273{
274	if (!vdev->config->get) {
275		dev_err(&vdev->dev, "configuration access disabled\n");
276		return -EINVAL;
277	}
278
279	if (!virtio_has_feature(vdev, VIRTIO_F_VERSION_1)) {
280		dev_err(&vdev->dev,
281			"device does not comply with spec version 1.x\n");
282		return -EINVAL;
283	}
284
285	if (!virtsnd_msg_timeout_ms) {
286		dev_err(&vdev->dev, "msg_timeout_ms value cannot be zero\n");
287		return -EINVAL;
288	}
289
290	if (virtsnd_pcm_validate(vdev))
291		return -EINVAL;
292
293	return 0;
294}
295
296/**
297 * virtsnd_probe() - Create and initialize the device.
298 * @vdev: VirtIO parent device.
299 *
300 * Context: Any context that permits to sleep.
301 * Return: 0 on success, -errno on failure.
302 */
303static int virtsnd_probe(struct virtio_device *vdev)
304{
305	struct virtio_snd *snd;
306	unsigned int i;
307	int rc;
308
309	snd = devm_kzalloc(&vdev->dev, sizeof(*snd), GFP_KERNEL);
310	if (!snd)
311		return -ENOMEM;
312
313	snd->vdev = vdev;
314	INIT_LIST_HEAD(&snd->ctl_msgs);
315	INIT_LIST_HEAD(&snd->pcm_list);
316
317	vdev->priv = snd;
318
319	for (i = 0; i < VIRTIO_SND_VQ_MAX; ++i)
320		spin_lock_init(&snd->queues[i].lock);
321
322	rc = virtsnd_find_vqs(snd);
323	if (rc)
324		goto on_exit;
325
326	virtio_device_ready(vdev);
327
328	rc = virtsnd_build_devs(snd);
329	if (rc)
330		goto on_exit;
331
332	virtsnd_enable_event_vq(snd);
333
334on_exit:
335	if (rc)
336		virtsnd_remove(vdev);
337
338	return rc;
339}
340
341/**
342 * virtsnd_remove() - Remove VirtIO and ALSA devices.
343 * @vdev: VirtIO parent device.
344 *
345 * Context: Any context that permits to sleep.
346 */
347static void virtsnd_remove(struct virtio_device *vdev)
348{
349	struct virtio_snd *snd = vdev->priv;
350	unsigned int i;
351
352	virtsnd_disable_event_vq(snd);
353	virtsnd_ctl_msg_cancel_all(snd);
354
355	if (snd->card)
356		snd_card_free(snd->card);
357
358	vdev->config->del_vqs(vdev);
359	virtio_reset_device(vdev);
360
361	for (i = 0; snd->substreams && i < snd->nsubstreams; ++i) {
362		struct virtio_pcm_substream *vss = &snd->substreams[i];
363
364		cancel_work_sync(&vss->elapsed_period);
365		virtsnd_pcm_msg_free(vss);
366	}
367
368	kfree(snd->event_msgs);
369}
370
371#ifdef CONFIG_PM_SLEEP
372/**
373 * virtsnd_freeze() - Suspend device.
374 * @vdev: VirtIO parent device.
375 *
376 * Context: Any context.
377 * Return: 0 on success, -errno on failure.
378 */
379static int virtsnd_freeze(struct virtio_device *vdev)
380{
381	struct virtio_snd *snd = vdev->priv;
382	unsigned int i;
383
384	virtsnd_disable_event_vq(snd);
385	virtsnd_ctl_msg_cancel_all(snd);
386
387	vdev->config->del_vqs(vdev);
388	virtio_reset_device(vdev);
389
390	for (i = 0; i < snd->nsubstreams; ++i)
391		cancel_work_sync(&snd->substreams[i].elapsed_period);
392
393	kfree(snd->event_msgs);
394	snd->event_msgs = NULL;
395
396	return 0;
397}
398
399/**
400 * virtsnd_restore() - Resume device.
401 * @vdev: VirtIO parent device.
402 *
403 * Context: Any context.
404 * Return: 0 on success, -errno on failure.
405 */
406static int virtsnd_restore(struct virtio_device *vdev)
407{
408	struct virtio_snd *snd = vdev->priv;
409	int rc;
410
411	rc = virtsnd_find_vqs(snd);
412	if (rc)
413		return rc;
414
415	virtio_device_ready(vdev);
416
417	virtsnd_enable_event_vq(snd);
418
419	return 0;
420}
421#endif /* CONFIG_PM_SLEEP */
422
423static const struct virtio_device_id id_table[] = {
424	{ VIRTIO_ID_SOUND, VIRTIO_DEV_ANY_ID },
425	{ 0 },
426};
427
428static unsigned int features[] = {
429	VIRTIO_SND_F_CTLS
430};
431
432static struct virtio_driver virtsnd_driver = {
433	.driver.name = KBUILD_MODNAME,
434	.id_table = id_table,
435	.feature_table = features,
436	.feature_table_size = ARRAY_SIZE(features),
437	.validate = virtsnd_validate,
438	.probe = virtsnd_probe,
439	.remove = virtsnd_remove,
440#ifdef CONFIG_PM_SLEEP
441	.freeze = virtsnd_freeze,
442	.restore = virtsnd_restore,
443#endif
444};
445
446module_virtio_driver(virtsnd_driver);
447
448MODULE_DEVICE_TABLE(virtio, id_table);
449MODULE_DESCRIPTION("Virtio sound card driver");
450MODULE_LICENSE("GPL");