xref: /openbmc/linux/sound/virtio/virtio_pcm.h (revision 575483e9)
1 /* SPDX-License-Identifier: GPL-2.0+ */
2 /*
3  * virtio-snd: Virtio sound device
4  * Copyright (C) 2021 OpenSynergy GmbH
5  */
6 #ifndef VIRTIO_SND_PCM_H
7 #define VIRTIO_SND_PCM_H
8 
9 #include <linux/atomic.h>
10 #include <linux/virtio_config.h>
11 #include <sound/pcm.h>
12 
13 struct virtio_pcm;
14 struct virtio_pcm_msg;
15 
16 /**
17  * struct virtio_pcm_substream - VirtIO PCM substream.
18  * @snd: VirtIO sound device.
19  * @nid: Function group node identifier.
20  * @sid: Stream identifier.
21  * @direction: Stream data flow direction (SNDRV_PCM_STREAM_XXX).
22  * @features: Stream VirtIO feature bit map (1 << VIRTIO_SND_PCM_F_XXX).
23  * @substream: Kernel ALSA substream.
24  * @hw: Kernel ALSA substream hardware descriptor.
25  * @elapsed_period: Kernel work to handle the elapsed period state.
26  * @lock: Spinlock that protects fields shared by interrupt handlers and
27  *        substream operators.
28  * @buffer_bytes: Current buffer size in bytes.
29  * @hw_ptr: Substream hardware pointer value in bytes [0 ... buffer_bytes).
30  * @xfer_enabled: Data transfer state (0 - off, 1 - on).
31  * @xfer_xrun: Data underflow/overflow state (0 - no xrun, 1 - xrun).
32  * @stopped: True if the substream is stopped and must be released on the device
33  *           side.
34  * @suspended: True if the substream is suspended and must be reconfigured on
35  *             the device side at resume.
36  * @msgs: Allocated I/O messages.
37  * @nmsgs: Number of allocated I/O messages.
38  * @msg_last_enqueued: Index of the last I/O message added to the virtqueue.
39  * @msg_count: Number of pending I/O messages in the virtqueue.
40  * @msg_empty: Notify when msg_count is zero.
41  */
42 struct virtio_pcm_substream {
43 	struct virtio_snd *snd;
44 	u32 nid;
45 	u32 sid;
46 	u32 direction;
47 	u32 features;
48 	struct snd_pcm_substream *substream;
49 	struct snd_pcm_hardware hw;
50 	struct work_struct elapsed_period;
51 	spinlock_t lock;
52 	size_t buffer_bytes;
53 	size_t hw_ptr;
54 	bool xfer_enabled;
55 	bool xfer_xrun;
56 	bool stopped;
57 	bool suspended;
58 	struct virtio_pcm_msg **msgs;
59 	unsigned int nmsgs;
60 	int msg_last_enqueued;
61 	unsigned int msg_count;
62 	wait_queue_head_t msg_empty;
63 };
64 
65 /**
66  * struct virtio_pcm_stream - VirtIO PCM stream.
67  * @substreams: VirtIO substreams belonging to the stream.
68  * @nsubstreams: Number of substreams.
69  * @chmaps: Kernel channel maps belonging to the stream.
70  * @nchmaps: Number of channel maps.
71  */
72 struct virtio_pcm_stream {
73 	struct virtio_pcm_substream **substreams;
74 	u32 nsubstreams;
75 	struct snd_pcm_chmap_elem *chmaps;
76 	u32 nchmaps;
77 };
78 
79 /**
80  * struct virtio_pcm - VirtIO PCM device.
81  * @list: VirtIO PCM list entry.
82  * @nid: Function group node identifier.
83  * @pcm: Kernel PCM device.
84  * @streams: VirtIO PCM streams (playback and capture).
85  */
86 struct virtio_pcm {
87 	struct list_head list;
88 	u32 nid;
89 	struct snd_pcm *pcm;
90 	struct virtio_pcm_stream streams[SNDRV_PCM_STREAM_LAST + 1];
91 };
92 
93 extern const struct snd_pcm_ops virtsnd_pcm_ops;
94 
95 int virtsnd_pcm_validate(struct virtio_device *vdev);
96 
97 int virtsnd_pcm_parse_cfg(struct virtio_snd *snd);
98 
99 int virtsnd_pcm_build_devs(struct virtio_snd *snd);
100 
101 void virtsnd_pcm_event(struct virtio_snd *snd, struct virtio_snd_event *event);
102 
103 void virtsnd_pcm_tx_notify_cb(struct virtqueue *vqueue);
104 
105 void virtsnd_pcm_rx_notify_cb(struct virtqueue *vqueue);
106 
107 struct virtio_pcm *virtsnd_pcm_find(struct virtio_snd *snd, u32 nid);
108 
109 struct virtio_pcm *virtsnd_pcm_find_or_create(struct virtio_snd *snd, u32 nid);
110 
111 struct virtio_snd_msg *
112 virtsnd_pcm_ctl_msg_alloc(struct virtio_pcm_substream *vss,
113 			  unsigned int command, gfp_t gfp);
114 
115 int virtsnd_pcm_msg_alloc(struct virtio_pcm_substream *vss,
116 			  unsigned int periods, unsigned int period_bytes);
117 
118 void virtsnd_pcm_msg_free(struct virtio_pcm_substream *vss);
119 
120 int virtsnd_pcm_msg_send(struct virtio_pcm_substream *vss);
121 
122 unsigned int virtsnd_pcm_msg_pending_num(struct virtio_pcm_substream *vss);
123 
124 #endif /* VIRTIO_SND_PCM_H */
125