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: Ezequiel Garcia <ezequ...@vanguardiasur.com.ar>
---
drivers/media/pci/tw686x/tw686x-audio.c | 48 ++++++++++++++++++---------------
drivers/media/pci/tw686x/tw686x-regs.h | 4 +++
drivers/media/pci/tw686x/tw686x.h | 5 ++--
3 files changed, 34 insertions(+), 23 deletions(-)
diff --git a/drivers/media/pci/tw686x/tw686x-audio.c
b/drivers/media/pci/tw686x/tw686x-audio.c
index a14d1b07edec..987a22663525 100644
--- a/drivers/media/pci/tw686x/tw686x-audio.c
+++ b/drivers/media/pci/tw686x/tw686x-audio.c
@@ -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,
diff --git a/drivers/media/pci/tw686x/tw686x-regs.h
b/drivers/media/pci/tw686x/tw686x-regs.h
index 37c39bcd7572..15a956642ef4 100644
--- a/drivers/media/pci/tw686x/tw686x-regs.h
+++ b/drivers/media/pci/tw686x/tw686x-regs.h
@@ -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)
diff --git a/drivers/media/pci/tw686x/tw686x.h
b/drivers/media/pci/tw686x/tw686x.h
index fe848a40f9d0..a5e94e0454d0 100644
--- a/drivers/media/pci/tw686x/tw686x.h
+++ b/drivers/media/pci/tw686x/tw686x.h
@@ -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 */
--
2.7.0
--
To unsubscribe from this list: send the line "unsubscribe linux-media" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
