diff options
Diffstat (limited to 'dummy')
| -rw-r--r-- | dummy/Kconfig | 12 | ||||
| -rw-r--r-- | dummy/Makefile | 6 | ||||
| -rw-r--r-- | dummy/dummy.c | 307 |
3 files changed, 325 insertions, 0 deletions
diff --git a/dummy/Kconfig b/dummy/Kconfig new file mode 100644 index 0000000..6a706c0 --- /dev/null +++ b/dummy/Kconfig @@ -0,0 +1,12 @@ +# +# AVIRT Dummy Audio Path +# + +config AVIRT_DUMMYAP + tristate "DummyAP" + select SND_PCM + ---help--- + Say Y here if you want to add dummy audio path. + + To compile this driver as a module, choose M here: the + module will be called avirt_dummyap. diff --git a/dummy/Makefile b/dummy/Makefile new file mode 100644 index 0000000..11ceceb --- /dev/null +++ b/dummy/Makefile @@ -0,0 +1,6 @@ +obj-$(CONFIG_AVIRT_AP_DUMMY) += snd-avirt-ap-dummy.o + +$(info $(src)) +snd-avirt-ap-dummy-objs := dummy.o +ccflags-y += -Idrivers/staging/ +ccflags-y += -I$(src)/../ diff --git a/dummy/dummy.c b/dummy/dummy.c new file mode 100644 index 0000000..5f19564 --- /dev/null +++ b/dummy/dummy.c @@ -0,0 +1,307 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Dummy Audio Path for AVIRT + * + * Original systimer code: + * Copyright (c) by Jaroslav Kysela <perex@perex.cz> + * + * Adapt to use AVIRT + * Copyright (c) 2010-2018 Fiberdyne Systems Pty Ltd + * + * dummy.c - Dummy Audio Path driver implementation for AVIRT + */ + +#include <linux/module.h> +#include <linux/slab.h> +#include <sound/avirt.h> + +MODULE_AUTHOR("James O'Shannessy <james.oshannessy@fiberdyne.com.au>"); +MODULE_AUTHOR("Mark Farrugia <mark.farrugia@fiberdyne.com.au>"); +MODULE_DESCRIPTION("Dummy Audio Path for AVIRT"); +MODULE_LICENSE("GPL v2"); + +#define AP_UID "ap_dummy" + +#define AP_INFOK(fmt, args...) DINFO(AP_UID, fmt, ##args) +#define AP_PRINTK(fmt, args...) DDEBUG(AP_UID, fmt, ##args) +#define AP_ERRORK(fmt, args...) DERROR(AP_UID, fmt, ##args) + +#define DUMMY_SAMPLE_RATE 48000 +#define DUMMY_BLOCKSIZE 512 +#define DUMMY_PERIODS_MIN 1 +#define DUMMY_PERIODS_MAX 8 + +#define get_dummy_ops(substream) \ + (*(const struct dummy_timer_ops **)(substream)->runtime->private_data) + +static struct snd_avirt_coreinfo *coreinfo; + +/******************************************************************************* + * System Timer Interface + * + * This is used to call the ALSA PCM callbacks required to notify AVIRT of the + * 'periods elapsed', so that buffers can keep getting transmitted here + * + * (Borrowed from the default ALSA 'dummy' driver (sound/driver/dummy.c)) + ******************************************************************************/ +struct dummy_timer_ops { + int (*create)(struct snd_pcm_substream *); + void (*free)(struct snd_pcm_substream *); + int (*prepare)(struct snd_pcm_substream *); + int (*start)(struct snd_pcm_substream *); + int (*stop)(struct snd_pcm_substream *); + snd_pcm_uframes_t (*pointer)(struct snd_pcm_substream *); +}; + +struct dummy_systimer_pcm { + /* ops must be the first item */ + const struct dummy_timer_ops *timer_ops; + spinlock_t lock; + struct timer_list timer; + unsigned long base_time; + unsigned int frac_pos; /* fractional sample position (based HZ) */ + unsigned int frac_period_rest; + unsigned int frac_buffer_size; /* buffer_size * HZ */ + unsigned int frac_period_size; /* period_size * HZ */ + unsigned int rate; + int elapsed; + struct snd_pcm_substream *substream; +}; + +static void dummy_systimer_rearm(struct dummy_systimer_pcm *dpcm) +{ + mod_timer(&dpcm->timer, jiffies + (dpcm->frac_period_rest + dpcm->rate - + 1) / dpcm->rate); +} + +static void dummy_systimer_update(struct dummy_systimer_pcm *dpcm) +{ + unsigned long delta; + + delta = jiffies - dpcm->base_time; + if (!delta) + return; + dpcm->base_time += delta; + delta *= dpcm->rate; + dpcm->frac_pos += delta; + while (dpcm->frac_pos >= dpcm->frac_buffer_size) + dpcm->frac_pos -= dpcm->frac_buffer_size; + while (dpcm->frac_period_rest <= delta) { + dpcm->elapsed++; + dpcm->frac_period_rest += dpcm->frac_period_size; + } + dpcm->frac_period_rest -= delta; +} + +static int dummy_systimer_start(struct snd_pcm_substream *substream) +{ + struct dummy_systimer_pcm *dpcm = substream->runtime->private_data; + spin_lock(&dpcm->lock); + dpcm->base_time = jiffies; + dummy_systimer_rearm(dpcm); + spin_unlock(&dpcm->lock); + return 0; +} + +static int dummy_systimer_stop(struct snd_pcm_substream *substream) +{ + struct dummy_systimer_pcm *dpcm = substream->runtime->private_data; + spin_lock(&dpcm->lock); + del_timer(&dpcm->timer); + spin_unlock(&dpcm->lock); + return 0; +} + +static int dummy_systimer_prepare(struct snd_pcm_substream *substream) +{ + struct snd_pcm_runtime *runtime = substream->runtime; + struct dummy_systimer_pcm *dpcm = runtime->private_data; + + dpcm->frac_pos = 0; + dpcm->rate = runtime->rate; + dpcm->frac_buffer_size = runtime->buffer_size * HZ; + dpcm->frac_period_size = runtime->period_size * HZ; + dpcm->frac_period_rest = dpcm->frac_period_size; + dpcm->elapsed = 0; + + return 0; +} + +static void dummy_systimer_callback(struct timer_list *t) +{ + struct dummy_systimer_pcm *dpcm = from_timer(dpcm, t, timer); + unsigned long flags; + int elapsed = 0; + + spin_lock_irqsave(&dpcm->lock, flags); + dummy_systimer_update(dpcm); + dummy_systimer_rearm(dpcm); + elapsed = dpcm->elapsed; + dpcm->elapsed = 0; + spin_unlock_irqrestore(&dpcm->lock, flags); + if (elapsed) + snd_avirt_pcm_period_elapsed(dpcm->substream); +} + +static snd_pcm_uframes_t + dummy_systimer_pointer(struct snd_pcm_substream *substream) +{ + struct dummy_systimer_pcm *dpcm = substream->runtime->private_data; + snd_pcm_uframes_t pos; + + spin_lock(&dpcm->lock); + dummy_systimer_update(dpcm); + pos = dpcm->frac_pos / HZ; + spin_unlock(&dpcm->lock); + return pos; +} + +static int dummy_systimer_create(struct snd_pcm_substream *substream) +{ + struct dummy_systimer_pcm *dpcm; + + dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL); + if (!dpcm) + return -ENOMEM; + substream->runtime->private_data = dpcm; + timer_setup(&dpcm->timer, dummy_systimer_callback, 0); + spin_lock_init(&dpcm->lock); + dpcm->substream = substream; + return 0; +} + +static void dummy_systimer_free(struct snd_pcm_substream *substream) +{ + kfree(substream->runtime->private_data); +} + +static const struct dummy_timer_ops dummy_systimer_ops = { + .create = dummy_systimer_create, + .free = dummy_systimer_free, + .prepare = dummy_systimer_prepare, + .start = dummy_systimer_start, + .stop = dummy_systimer_stop, + .pointer = dummy_systimer_pointer, +}; + +/******************************************************************************* + * Audio Path ALSA PCM Callbacks + ******************************************************************************/ +static int dummy_pcm_open(struct snd_pcm_substream *substream) +{ + const struct dummy_timer_ops *ops; + int err; + + ops = &dummy_systimer_ops; + err = ops->create(substream); + if (err < 0) + return err; + get_dummy_ops(substream) = ops; + + return 0; +} + +static int dummy_pcm_close(struct snd_pcm_substream *substream) +{ + get_dummy_ops(substream)->free(substream); + return 0; +} + +static snd_pcm_uframes_t dummy_pcm_pointer(struct snd_pcm_substream *substream) +{ + return get_dummy_ops(substream)->pointer(substream); +} + +static int dummy_pcm_trigger(struct snd_pcm_substream *substream, int cmd) +{ + switch (cmd) { + case SNDRV_PCM_TRIGGER_START: + case SNDRV_PCM_TRIGGER_RESUME: + return get_dummy_ops(substream)->start(substream); + case SNDRV_PCM_TRIGGER_STOP: + case SNDRV_PCM_TRIGGER_SUSPEND: + return get_dummy_ops(substream)->stop(substream); + } + return -EINVAL; +} + +static int dummy_pcm_prepare(struct snd_pcm_substream *substream) +{ + return get_dummy_ops(substream)->prepare(substream); +} + +static struct snd_pcm_ops dummyap_pcm_ops = { + .open = dummy_pcm_open, + .close = dummy_pcm_close, + .prepare = dummy_pcm_prepare, + .pointer = dummy_pcm_pointer, + .trigger = dummy_pcm_trigger, +}; + +/******************************************************************************* + * Dummy Audio Path AVIRT registration + ******************************************************************************/ +static int dummy_configure(struct snd_card *card, + struct config_group *snd_avirt_stream_group, + unsigned int stream_count) +{ + // Do something with streams + + struct list_head *entry; + list_for_each (entry, &snd_avirt_stream_group->cg_children) { + struct config_item *item = + container_of(entry, struct config_item, ci_entry); + struct snd_avirt_stream *stream = + snd_avirt_stream_from_config_item(item); + AP_INFOK("stream name:%s device:%d channels:%d", stream->name, + stream->device, stream->channels); + } + + return 0; +} + +static struct snd_pcm_hardware dummyap_hw = { + .formats = SNDRV_PCM_FMTBIT_S16_LE, + .info = (SNDRV_PCM_INFO_INTERLEAVED // Channel interleaved audio + | SNDRV_PCM_INFO_BLOCK_TRANSFER | SNDRV_PCM_INFO_MMAP | + SNDRV_PCM_INFO_MMAP_VALID), + .rates = SNDRV_PCM_RATE_48000, + .rate_min = DUMMY_SAMPLE_RATE, + .rate_max = DUMMY_SAMPLE_RATE, + .periods_min = DUMMY_PERIODS_MIN, + .periods_max = DUMMY_PERIODS_MAX, +}; + +static struct snd_avirt_audiopath dummyap_module = { + .uid = "ap_dummy", + .name = "Dummy Audio Path", + .version = { 0, 0, 1 }, + .hw = &dummyap_hw, + .pcm_ops = &dummyap_pcm_ops, + .configure = dummy_configure, +}; + +static int __init dummy_init(void) +{ + int err = 0; + + pr_info("init()\n"); + + err = snd_avirt_audiopath_register(&dummyap_module, &coreinfo); + if ((err < 0) || (!coreinfo)) { + pr_err("%s: coreinfo is NULL!\n", __func__); + return err; + } + + return err; +} + +static void __exit dummy_exit(void) +{ + pr_info("exit()\n"); + + snd_avirt_audiopath_deregister(&dummyap_module); +} + +module_init(dummy_init); +module_exit(dummy_exit); |