linuxdebug/drivers/media/pci/cx18/cx18-alsa-pcm.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  ALSA PCM device for the
 *  ALSA interface to cx18 PCM capture streams
 *
 *  Copyright (C) 2009  Andy Walls <awalls@md.metrocast.net>
 *  Copyright (C) 2009  Devin Heitmueller <dheitmueller@kernellabs.com>
 *
 *  Portions of this work were sponsored by ONELAN Limited.
 */

#include <linux/init.h>
#include <linux/kernel.h>

#include <media/v4l2-device.h>

#include <sound/core.h>
#include <sound/pcm.h>

#include "cx18-driver.h"
#include "cx18-queue.h"
#include "cx18-streams.h"
#include "cx18-fileops.h"
#include "cx18-alsa.h"
#include "cx18-alsa-pcm.h"

static unsigned int pcm_debug;
module_param(pcm_debug, int, 0644);
MODULE_PARM_DESC(pcm_debug, "enable debug messages for pcm");

#define dprintk(fmt, arg...) do {					\
	    if (pcm_debug)						\
		printk(KERN_INFO "cx18-alsa-pcm %s: " fmt,		\
				  __func__, ##arg);			\
	} while (0)

static const struct snd_pcm_hardware snd_cx18_hw_capture = {
	.info = SNDRV_PCM_INFO_BLOCK_TRANSFER |
		SNDRV_PCM_INFO_MMAP           |
		SNDRV_PCM_INFO_INTERLEAVED    |
		SNDRV_PCM_INFO_MMAP_VALID,

	.formats = SNDRV_PCM_FMTBIT_S16_LE,

	.rates = SNDRV_PCM_RATE_48000,

	.rate_min = 48000,
	.rate_max = 48000,
	.channels_min = 2,
	.channels_max = 2,
	.buffer_bytes_max = 62720 * 8,	/* just about the value in usbaudio.c */
	.period_bytes_min = 64,		/* 12544/2, */
	.period_bytes_max = 12544,
	.periods_min = 2,
	.periods_max = 98,		/* 12544, */
};

void cx18_alsa_announce_pcm_data(struct snd_cx18_card *cxsc, u8 *pcm_data,
				 size_t num_bytes)
{
	struct snd_pcm_substream *substream;
	struct snd_pcm_runtime *runtime;
	unsigned int oldptr;
	unsigned int stride;
	int period_elapsed = 0;
	int length;

	dprintk("cx18 alsa announce ptr=%p data=%p num_bytes=%zu\n", cxsc,
		pcm_data, num_bytes);

	substream = cxsc->capture_pcm_substream;
	if (substream == NULL) {
		dprintk("substream was NULL\n");
		return;
	}

	runtime = substream->runtime;
	if (runtime == NULL) {
		dprintk("runtime was NULL\n");
		return;
	}

	stride = runtime->frame_bits >> 3;
	if (stride == 0) {
		dprintk("stride is zero\n");
		return;
	}

	length = num_bytes / stride;
	if (length == 0) {
		dprintk("%s: length was zero\n", __func__);
		return;
	}

	if (runtime->dma_area == NULL) {
		dprintk("dma area was NULL - ignoring\n");
		return;
	}

	oldptr = cxsc->hwptr_done_capture;
	if (oldptr + length >= runtime->buffer_size) {
		unsigned int cnt =
			runtime->buffer_size - oldptr;
		memcpy(runtime->dma_area + oldptr * stride, pcm_data,
		       cnt * stride);
		memcpy(runtime->dma_area, pcm_data + cnt * stride,
		       length * stride - cnt * stride);
	} else {
		memcpy(runtime->dma_area + oldptr * stride, pcm_data,
		       length * stride);
	}
	snd_pcm_stream_lock(substream);

	cxsc->hwptr_done_capture += length;
	if (cxsc->hwptr_done_capture >=
	    runtime->buffer_size)
		cxsc->hwptr_done_capture -=
			runtime->buffer_size;

	cxsc->capture_transfer_done += length;
	if (cxsc->capture_transfer_done >=
	    runtime->period_size) {
		cxsc->capture_transfer_done -=
			runtime->period_size;
		period_elapsed = 1;
	}

	snd_pcm_stream_unlock(substream);

	if (period_elapsed)
		snd_pcm_period_elapsed(substream);
}

static int snd_cx18_pcm_capture_open(struct snd_pcm_substream *substream)
{
	struct snd_cx18_card *cxsc = snd_pcm_substream_chip(substream);
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct v4l2_device *v4l2_dev = cxsc->v4l2_dev;
	struct cx18 *cx = to_cx18(v4l2_dev);
	struct cx18_stream *s;
	struct cx18_open_id item;
	int ret;

	/* Instruct the cx18 to start sending packets */
	snd_cx18_lock(cxsc);
	s = &cx->streams[CX18_ENC_STREAM_TYPE_PCM];

	item.cx = cx;
	item.type = s->type;
	item.open_id = cx->open_id++;

	/* See if the stream is available */
	if (cx18_claim_stream(&item, item.type)) {
		/* No, it's already in use */
		snd_cx18_unlock(cxsc);
		return -EBUSY;
	}

	if (test_bit(CX18_F_S_STREAMOFF, &s->s_flags) ||
	    test_and_set_bit(CX18_F_S_STREAMING, &s->s_flags)) {
		/* We're already streaming.  No additional action required */
		snd_cx18_unlock(cxsc);
		return 0;
	}


	runtime->hw = snd_cx18_hw_capture;
	snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
	cxsc->capture_pcm_substream = substream;
	runtime->private_data = cx;

	cx->pcm_announce_callback = cx18_alsa_announce_pcm_data;

	/* Not currently streaming, so start it up */
	set_bit(CX18_F_S_STREAMING, &s->s_flags);
	ret = cx18_start_v4l2_encode_stream(s);
	snd_cx18_unlock(cxsc);

	return ret;
}

static int snd_cx18_pcm_capture_close(struct snd_pcm_substream *substream)
{
	struct snd_cx18_card *cxsc = snd_pcm_substream_chip(substream);
	struct v4l2_device *v4l2_dev = cxsc->v4l2_dev;
	struct cx18 *cx = to_cx18(v4l2_dev);
	struct cx18_stream *s;

	/* Instruct the cx18 to stop sending packets */
	snd_cx18_lock(cxsc);
	s = &cx->streams[CX18_ENC_STREAM_TYPE_PCM];
	cx18_stop_v4l2_encode_stream(s, 0);
	clear_bit(CX18_F_S_STREAMING, &s->s_flags);

	cx18_release_stream(s);

	cx->pcm_announce_callback = NULL;
	snd_cx18_unlock(cxsc);

	return 0;
}

static int snd_cx18_pcm_prepare(struct snd_pcm_substream *substream)
{
	struct snd_cx18_card *cxsc = snd_pcm_substream_chip(substream);

	cxsc->hwptr_done_capture = 0;
	cxsc->capture_transfer_done = 0;

	return 0;
}

static int snd_cx18_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
{
	return 0;
}

static
snd_pcm_uframes_t snd_cx18_pcm_pointer(struct snd_pcm_substream *substream)
{
	unsigned long flags;
	snd_pcm_uframes_t hwptr_done;
	struct snd_cx18_card *cxsc = snd_pcm_substream_chip(substream);

	spin_lock_irqsave(&cxsc->slock, flags);
	hwptr_done = cxsc->hwptr_done_capture;
	spin_unlock_irqrestore(&cxsc->slock, flags);

	return hwptr_done;
}

static const struct snd_pcm_ops snd_cx18_pcm_capture_ops = {
	.open		= snd_cx18_pcm_capture_open,
	.close		= snd_cx18_pcm_capture_close,
	.prepare	= snd_cx18_pcm_prepare,
	.trigger	= snd_cx18_pcm_trigger,
	.pointer	= snd_cx18_pcm_pointer,
};

int snd_cx18_pcm_create(struct snd_cx18_card *cxsc)
{
	struct snd_pcm *sp;
	struct snd_card *sc = cxsc->sc;
	struct v4l2_device *v4l2_dev = cxsc->v4l2_dev;
	struct cx18 *cx = to_cx18(v4l2_dev);
	int ret;

	ret = snd_pcm_new(sc, "CX23418 PCM",
			  0, /* PCM device 0, the only one for this card */
			  0, /* 0 playback substreams */
			  1, /* 1 capture substream */
			  &sp);
	if (ret) {
		CX18_ALSA_ERR("%s: snd_cx18_pcm_create() failed with err %d\n",
			      __func__, ret);
		goto err_exit;
	}

	spin_lock_init(&cxsc->slock);

	snd_pcm_set_ops(sp, SNDRV_PCM_STREAM_CAPTURE,
			&snd_cx18_pcm_capture_ops);
	snd_pcm_set_managed_buffer_all(sp, SNDRV_DMA_TYPE_VMALLOC, NULL, 0, 0);
	sp->info_flags = 0;
	sp->private_data = cxsc;
	strscpy(sp->name, cx->card_name, sizeof(sp->name));

	return 0;

err_exit:
	return ret;
}