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Commit 447d7c32 authored by Ezequiel Garcia's avatar Ezequiel Garcia Committed by Mauro Carvalho Chehab
Browse files

[media] tw686x: audio: Allow to configure the period size 



Currently, the driver has a fixed period size of 4096 bytes
(2048 frames). Since this hardware can configure the audio
capture size, this commit allows a period size range of [512-4096].

This is very useful to reduce the audio latency.

Signed-off-by: default avatarEzequiel Garcia <ezequiel@vanguardiasur.com.ar>
Signed-off-by: default avatarHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@s-opensource.com>
parent c156c54d

drivers/media/pci/tw686x/tw686x-audio.c

+27 −21
Original line number Diff line number Diff line
@@ -71,7 +71,7 @@ void tw686x_audio_irq(struct tw686x_dev *dev, unsigned long requests, 
		desc = &ac->dma_descs[pb];

		if (desc->virt) {

			memcpy(done->virt, desc->virt,

			       desc->size);

			       dev->period_size);

		} else {

			u32 reg = pb ? ADMA_B_ADDR[ch] : ADMA_P_ADDR[ch];

			reg_write(dev, reg, next->dma);
@@ -93,10 +93,11 @@ static int tw686x_pcm_hw_free(struct snd_pcm_substream *ss) 
}



/*

 * The audio device rate is global and shared among all

 * Audio parameters are global and shared among all

 * capture channels. The driver makes no effort to prevent

 * rate modifications. User is free change the rate, but it

 * means changing the rate for all capture sub-devices.

 * any modifications. User is free change the audio rate,

 * or period size, thus changing parameters for all capture

 * sub-devices.

 */

static const struct snd_pcm_hardware tw686x_capture_hw = {

	.info			= (SNDRV_PCM_INFO_MMAP |
@@ -109,9 +110,9 @@ static const struct snd_pcm_hardware tw686x_capture_hw = { 
	.rate_max		= 48000,

	.channels_min		= 1,

	.channels_max		= 1,

	.buffer_bytes_max	= TW686X_AUDIO_PAGE_MAX * TW686X_AUDIO_PAGE_SZ,

	.period_bytes_min	= TW686X_AUDIO_PAGE_SZ,

	.period_bytes_max	= TW686X_AUDIO_PAGE_SZ,

	.buffer_bytes_max	= TW686X_AUDIO_PAGE_MAX * AUDIO_DMA_SIZE_MAX,

	.period_bytes_min	= AUDIO_DMA_SIZE_MIN,

	.period_bytes_max	= AUDIO_DMA_SIZE_MAX,

	.periods_min		= TW686X_AUDIO_PERIODS_MIN,

	.periods_max		= TW686X_AUDIO_PERIODS_MAX,

};
@@ -166,12 +167,21 @@ static int tw686x_pcm_prepare(struct snd_pcm_substream *ss) 
		reg_write(dev, AUDIO_CONTROL2, reg);

	}



	if (period_size != TW686X_AUDIO_PAGE_SZ ||

	    rt->periods < TW686X_AUDIO_PERIODS_MIN ||

	    rt->periods > TW686X_AUDIO_PERIODS_MAX) {

		return -EINVAL;

	if (dev->period_size != period_size) {

		u32 reg;



		dev->period_size = period_size;

		reg = reg_read(dev, AUDIO_CONTROL1);

		reg &= ~(AUDIO_DMA_SIZE_MASK << AUDIO_DMA_SIZE_SHIFT);

		reg |= period_size << AUDIO_DMA_SIZE_SHIFT;



		reg_write(dev, AUDIO_CONTROL1, reg);

	}



	if (rt->periods < TW686X_AUDIO_PERIODS_MIN ||

	    rt->periods > TW686X_AUDIO_PERIODS_MAX)

		return -EINVAL;



	spin_lock_irqsave(&ac->lock, flags);

	INIT_LIST_HEAD(&ac->buf_list);
@@ -282,8 +292,8 @@ static int tw686x_snd_pcm_init(struct tw686x_dev *dev) 
	return snd_pcm_lib_preallocate_pages_for_all(pcm,

				SNDRV_DMA_TYPE_DEV,

				snd_dma_pci_data(dev->pci_dev),

				TW686X_AUDIO_PAGE_MAX * TW686X_AUDIO_PAGE_SZ,

				TW686X_AUDIO_PAGE_MAX * TW686X_AUDIO_PAGE_SZ);

				TW686X_AUDIO_PAGE_MAX * AUDIO_DMA_SIZE_MAX,

				TW686X_AUDIO_PAGE_MAX * AUDIO_DMA_SIZE_MAX);

}



static void tw686x_audio_dma_free(struct tw686x_dev *dev,
@@ -318,7 +328,7 @@ static int tw686x_audio_dma_alloc(struct tw686x_dev *dev, 
		u32 reg = pb ? ADMA_B_ADDR[ac->ch] : ADMA_P_ADDR[ac->ch];

		void *virt;



		virt = pci_alloc_consistent(dev->pci_dev, TW686X_AUDIO_PAGE_SZ,

		virt = pci_alloc_consistent(dev->pci_dev, AUDIO_DMA_SIZE_MAX,

					    &ac->dma_descs[pb].phys);

		if (!virt) {

			dev_err(&dev->pci_dev->dev,
@@ -327,7 +337,7 @@ static int tw686x_audio_dma_alloc(struct tw686x_dev *dev, 
			return -ENOMEM;

		}

		ac->dma_descs[pb].virt = virt;

		ac->dma_descs[pb].size = TW686X_AUDIO_PAGE_SZ;

		ac->dma_descs[pb].size = AUDIO_DMA_SIZE_MAX;

		reg_write(dev, reg, ac->dma_descs[pb].phys);

	}

	return 0;
@@ -358,12 +368,8 @@ int tw686x_audio_init(struct tw686x_dev *dev) 
	struct snd_card *card;

	int err, ch;



	/*

	 * AUDIO_CONTROL1

	 * DMA byte length [31:19] = 4096 (i.e. ALSA period)

	 * External audio enable [0] = enabled

	 */

	reg_write(dev, AUDIO_CONTROL1, 0x80000001);

	/* Enable external audio */

	reg_write(dev, AUDIO_CONTROL1, BIT(0));



	err = snd_card_new(&pci_dev->dev, SNDRV_DEFAULT_IDX1,

			   SNDRV_DEFAULT_STR1,

drivers/media/pci/tw686x/tw686x-regs.h

+4 −0
Original line number Diff line number Diff line
@@ -105,6 +105,10 @@ 
						  0x2d0, 0x2d1, 0x2d2, 0x2d3 })



#define SYS_MODE_DMA_SHIFT	13

#define AUDIO_DMA_SIZE_SHIFT	19

#define AUDIO_DMA_SIZE_MIN	SZ_512

#define AUDIO_DMA_SIZE_MAX	SZ_4K

#define AUDIO_DMA_SIZE_MASK	(SZ_8K - 1)



#define DMA_CMD_ENABLE		BIT(31)

#define INT_STATUS_DMA_TOUT	BIT(17)

drivers/media/pci/tw686x/tw686x.h

+3 −2
Original line number Diff line number Diff line
@@ -27,7 +27,6 @@ 
#define TYPE_SECOND_GEN		0x10

#define TW686X_DEF_PHASE_REF	0x1518



#define TW686X_AUDIO_PAGE_SZ		4096

#define TW686X_AUDIO_PAGE_MAX		16

#define TW686X_AUDIO_PERIODS_MIN	2

#define TW686X_AUDIO_PERIODS_MAX	TW686X_AUDIO_PAGE_MAX
@@ -139,7 +138,9 @@ struct tw686x_dev { 
	struct tw686x_video_channel *video_channels;

	struct tw686x_audio_channel *audio_channels;



	int audio_rate; /* per-device value */

	/* Per-device audio parameters */

	int audio_rate;

	int period_size;



	struct timer_list dma_delay_timer;

	u32 pending_dma_en; /* must be protected by lock */