[PATCH v5 0/5] OMAP/ASoC: McBSP: FIFO handling related fixes

[PATCH v5 0/5] OMAP/ASoC: McBSP: FIFO handling related fixes

[Peter Ujfalusi]

Hello,

Tony: Could you take a look at the arch/arm patches in this series?
Thanks!

Changes since v3/4:
- Fixed commit subjects and messages for OMAP3 related patches
- Added Acked-by from Mark, and Jarkko

Intro message from the original series:

This series aims to correct how the McBSP FIFO is viewed, and handled.

Introduction of the problem:
OMAP McBSP FIFO is word structured:
McBSP2 has 1024 + 256 = 1280 word long buffer,
McBSP1,3,4,5 has 128 word long buffer

This means, that the size of the FIFO
depends on the McBSP word size configuration.
For example on McBSP3:
16bit samples: size is 128 * 2 = 256 bytes
32bit samples: size is 128 * 4 = 512 bytes
It is simpler to place constraint for buffer and period based on channels.
McBSP3 as example again (16 or 32 bit samples):
1 channel (mono): size is 128 frames (128 words)
2 channels (stereo): size is 128 / 2 = 64 frames (2 * 64 words)
4 channels: size is 128 / 4 = 32 frames (4 * 32 words)

Since now the McBSP codec supports not only 16bit samples (32biut has been
recently added), the FIFO size handling is no longer correct, since it has
been hard wired for 16bit word length.

The series changes how the users of McBSP are configuring the FIFO:
It used to be 0 based (0 meant 1 word threshold). After this series users can
configure the threshold in 1 base mode (1 means 1 word threshold).
The platform code now provides the full size of the FIFO in words, instead of
the already limited value used in the past.

In ASoC omap-mcbsp code hw_rule based constraint refinement is going to be used
instead of the hardwired static constraint, which was correct only in case of
16bit word length.

The hw_rule is refining the minimum buffer size based on the channel number
going to be used by the coming stream.
In case of threshold mode additional hw_rule refines the maximum allowed period
size.

The series are generated agains Takashi's sound-2.6: topic/asoc branch.

CCing also Eduardo, and Eero since they have worked on the original
FIFO/threshold implementation.

All commetns and testers are welcome!
Peter

---
Peter Ujfalusi (5):
  OMAP: McBSP: Function to query the FIFO size
  OMAP3: McBSP: Change the way how the FIFO is handled
  OMAP3: McBSP: Use the port's buffer_size when calculating tx delay
  ASoC: omap-mcbsp: Save, and use wlen for threshold configuration
  ASoC: omap-mcbsp: Place correct constraints for streams

 arch/arm/mach-omap2/mcbsp.c             |   10 ++--
 arch/arm/plat-omap/include/plat/mcbsp.h |    2 +
 arch/arm/plat-omap/mcbsp.c              |   51 ++++++++++-----
 sound/soc/omap/omap-mcbsp.c             |  112 +++++++++++++++++++++++-------
 4 files changed, 128 insertions(+), 47 deletions(-)

[PATCH v5 1/5] OMAP: McBSP: Function to query the FIFO size

[Peter Ujfalusi]

Users of McBSP can use the omap_mcbsp_get_fifo_size function to query
the size of the McBSP FIFO.
The function will return the FIFO size in words (the HW maximum).

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@nokia.com>
Acked-by: Jarkko Nikula <jhnikula@gmail.com>
Acked-by: Mark Brown <broonie@opensource.wolsfonmicro.com>
---
 arch/arm/plat-omap/include/plat/mcbsp.h |    2 ++
 arch/arm/plat-omap/mcbsp.c              |   14 ++++++++++++++
 2 files changed, 16 insertions(+), 0 deletions(-)

diff --git a/arch/arm/plat-omap/include/plat/mcbsp.h b/arch/arm/plat-omap/include/plat/mcbsp.h
index 1bd7021..e126951 100644
--- a/arch/arm/plat-omap/include/plat/mcbsp.h
+++ b/arch/arm/plat-omap/include/plat/mcbsp.h
@@ -473,6 +473,7 @@ void omap_mcbsp_set_tx_threshold(unsigned int id, u16 threshold);
 void omap_mcbsp_set_rx_threshold(unsigned int id, u16 threshold);
 u16 omap_mcbsp_get_max_tx_threshold(unsigned int id);
 u16 omap_mcbsp_get_max_rx_threshold(unsigned int id);
+u16 omap_mcbsp_get_fifo_size(unsigned int id);
 u16 omap_mcbsp_get_tx_delay(unsigned int id);
 u16 omap_mcbsp_get_rx_delay(unsigned int id);
 int omap_mcbsp_get_dma_op_mode(unsigned int id);
@@ -483,6 +484,7 @@ static inline void omap_mcbsp_set_rx_threshold(unsigned int id, u16 threshold)
 { }
 static inline u16 omap_mcbsp_get_max_tx_threshold(unsigned int id) { return 0; }
 static inline u16 omap_mcbsp_get_max_rx_threshold(unsigned int id) { return 0; }
+static inline u16 omap_mcbsp_get_fifo_size(unsigned int id) { return 0; }
 static inline u16 omap_mcbsp_get_tx_delay(unsigned int id) { return 0; }
 static inline u16 omap_mcbsp_get_rx_delay(unsigned int id) { return 0; }
 static inline int omap_mcbsp_get_dma_op_mode(unsigned int id) { return 0; }
diff --git a/arch/arm/plat-omap/mcbsp.c b/arch/arm/plat-omap/mcbsp.c
index 4820cab..51d8abf 100644
--- a/arch/arm/plat-omap/mcbsp.c
+++ b/arch/arm/plat-omap/mcbsp.c
@@ -559,6 +559,20 @@ u16 omap_mcbsp_get_max_rx_threshold(unsigned int id)
 }
 EXPORT_SYMBOL(omap_mcbsp_get_max_rx_threshold);
 
+u16 omap_mcbsp_get_fifo_size(unsigned int id)
+{
+	struct omap_mcbsp *mcbsp;
+
+	if (!omap_mcbsp_check_valid_id(id)) {
+		printk(KERN_ERR "%s: Invalid id (%d)\n", __func__, id + 1);
+		return -ENODEV;
+	}
+	mcbsp = id_to_mcbsp_ptr(id);
+
+	return mcbsp->pdata->buffer_size;
+}
+EXPORT_SYMBOL(omap_mcbsp_get_fifo_size);
+
 #define MCBSP2_FIFO_SIZE	0x500 /* 1024 + 256 locations */
 #define MCBSP1345_FIFO_SIZE	0x80  /* 128 locations */
 /*
-- 
1.7.1

[PATCH v5 2/5] OMAP3: McBSP: Change the way how the FIFO is handled

[Peter Ujfalusi]

Use the actual FIFO size in words as buffer_size on OMAP3.
Change the threshold configuration to use 1 based numbering, when
specifying the allowed threshold maximum or the McBSP threshold value.
Set the default maximum threshold to (buffer_size - 0x10) intialy.
>From users of McBSP, now it is expected to use this method.
Asking for threshold 1 means that the value written to threshold registers
are going to be 0, which means 1 word threshold.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@nokia.com>
Acked-by: Jarkko Nikula <jhnikula@gmail.com>
Acked-by: Mark Brown <broonie@opensource.wolsfonmicro.com>
---
 arch/arm/mach-omap2/mcbsp.c |   10 +++++-----
 arch/arm/plat-omap/mcbsp.c  |   30 ++++++++++++++++++++----------
 2 files changed, 25 insertions(+), 15 deletions(-)

diff --git a/arch/arm/mach-omap2/mcbsp.c b/arch/arm/mach-omap2/mcbsp.c
index 016fe60..ed9f562 100644
--- a/arch/arm/mach-omap2/mcbsp.c
+++ b/arch/arm/mach-omap2/mcbsp.c
@@ -132,7 +132,7 @@ static struct omap_mcbsp_platform_data omap34xx_mcbsp_pdata[] = {
 		.rx_irq		= INT_24XX_MCBSP1_IRQ_RX,
 		.tx_irq		= INT_24XX_MCBSP1_IRQ_TX,
 		.ops		= &omap2_mcbsp_ops,
-		.buffer_size	= 0x6F,
+		.buffer_size	= 0x80, /* The FIFO has 128 locations */
 	},
 	{
 		.phys_base	= OMAP34XX_MCBSP2_BASE,
@@ -142,7 +142,7 @@ static struct omap_mcbsp_platform_data omap34xx_mcbsp_pdata[] = {
 		.rx_irq		= INT_24XX_MCBSP2_IRQ_RX,
 		.tx_irq		= INT_24XX_MCBSP2_IRQ_TX,
 		.ops		= &omap2_mcbsp_ops,
-		.buffer_size	= 0x3FF,
+		.buffer_size	= 0x500, /* The FIFO has 1024 + 256 locations */
 	},
 	{
 		.phys_base	= OMAP34XX_MCBSP3_BASE,
@@ -152,7 +152,7 @@ static struct omap_mcbsp_platform_data omap34xx_mcbsp_pdata[] = {
 		.rx_irq		= INT_24XX_MCBSP3_IRQ_RX,
 		.tx_irq		= INT_24XX_MCBSP3_IRQ_TX,
 		.ops		= &omap2_mcbsp_ops,
-		.buffer_size	= 0x6F,
+		.buffer_size	= 0x80, /* The FIFO has 128 locations */
 	},
 	{
 		.phys_base	= OMAP34XX_MCBSP4_BASE,
@@ -161,7 +161,7 @@ static struct omap_mcbsp_platform_data omap34xx_mcbsp_pdata[] = {
 		.rx_irq		= INT_24XX_MCBSP4_IRQ_RX,
 		.tx_irq		= INT_24XX_MCBSP4_IRQ_TX,
 		.ops		= &omap2_mcbsp_ops,
-		.buffer_size	= 0x6F,
+		.buffer_size	= 0x80, /* The FIFO has 128 locations */
 	},
 	{
 		.phys_base	= OMAP34XX_MCBSP5_BASE,
@@ -170,7 +170,7 @@ static struct omap_mcbsp_platform_data omap34xx_mcbsp_pdata[] = {
 		.rx_irq		= INT_24XX_MCBSP5_IRQ_RX,
 		.tx_irq		= INT_24XX_MCBSP5_IRQ_TX,
 		.ops		= &omap2_mcbsp_ops,
-		.buffer_size	= 0x6F,
+		.buffer_size	= 0x80, /* The FIFO has 128 locations */
 	},
 };
 #define OMAP34XX_MCBSP_PDATA_SZ		ARRAY_SIZE(omap34xx_mcbsp_pdata)
diff --git a/arch/arm/plat-omap/mcbsp.c b/arch/arm/plat-omap/mcbsp.c
index 51d8abf..d883bbf 100644
--- a/arch/arm/plat-omap/mcbsp.c
+++ b/arch/arm/plat-omap/mcbsp.c
@@ -480,9 +480,9 @@ int omap_st_is_enabled(unsigned int id)
 EXPORT_SYMBOL(omap_st_is_enabled);
 
 /*
- * omap_mcbsp_set_tx_threshold configures how to deal
- * with transmit threshold. the threshold value and handler can be
- * configure in here.
+ * omap_mcbsp_set_rx_threshold configures the transmit threshold in words.
+ * The threshold parameter is 1 based, and it is converted (threshold - 1)
+ * for the THRSH2 register.
  */
 void omap_mcbsp_set_tx_threshold(unsigned int id, u16 threshold)
 {
@@ -497,14 +497,15 @@ void omap_mcbsp_set_tx_threshold(unsigned int id, u16 threshold)
 	}
 	mcbsp = id_to_mcbsp_ptr(id);
 
-	MCBSP_WRITE(mcbsp, THRSH2, threshold);
+	if (threshold && threshold <= mcbsp->max_tx_thres)
+		MCBSP_WRITE(mcbsp, THRSH2, threshold - 1);
 }
 EXPORT_SYMBOL(omap_mcbsp_set_tx_threshold);
 
 /*
- * omap_mcbsp_set_rx_threshold configures how to deal
- * with receive threshold. the threshold value and handler can be
- * configure in here.
+ * omap_mcbsp_set_rx_threshold configures the receive threshold in words.
+ * The threshold parameter is 1 based, and it is converted (threshold - 1)
+ * for the THRSH1 register.
  */
 void omap_mcbsp_set_rx_threshold(unsigned int id, u16 threshold)
 {
@@ -519,7 +520,8 @@ void omap_mcbsp_set_rx_threshold(unsigned int id, u16 threshold)
 	}
 	mcbsp = id_to_mcbsp_ptr(id);
 
-	MCBSP_WRITE(mcbsp, THRSH1, threshold);
+	if (threshold && threshold <= mcbsp->max_rx_thres)
+		MCBSP_WRITE(mcbsp, THRSH1, threshold - 1);
 }
 EXPORT_SYMBOL(omap_mcbsp_set_rx_threshold);
 
@@ -1696,8 +1698,16 @@ static inline void __devinit omap34xx_device_init(struct omap_mcbsp *mcbsp)
 {
 	mcbsp->dma_op_mode = MCBSP_DMA_MODE_ELEMENT;
 	if (cpu_is_omap34xx()) {
-		mcbsp->max_tx_thres = max_thres(mcbsp);
-		mcbsp->max_rx_thres = max_thres(mcbsp);
+		/*
+		 * Initially configure the maximum thresholds to a safe value.
+		 * The McBSP FIFO usage with these values should not go under
+		 * 16 locations.
+		 * If the whole FIFO without safety buffer is used, than there
+		 * is a possibility that the DMA will be not able to push the
+		 * new data on time, causing channel shifts in runtime.
+		 */
+		mcbsp->max_tx_thres = max_thres(mcbsp) - 0x10;
+		mcbsp->max_rx_thres = max_thres(mcbsp) - 0x10;
 		/*
 		 * REVISIT: Set dmap_op_mode to THRESHOLD as default
 		 * for mcbsp2 instances.
-- 
1.7.1

[PATCH v5 3/5] OMAP3: McBSP: Use the port's buffer_size when calculating tx delay

[Peter Ujfalusi]

Sicne the platform data's buffer_size now holds the full size
of the FIFO, there is no longer need to handle the ports
differently.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@nokia.com>
Acked-by: Jarkko Nikula <jhnikula@gmail.com>
Acked-by: Mark Brown <broonie@opensource.wolsfonmicro.com>
---
 arch/arm/plat-omap/mcbsp.c |    7 +------
 1 files changed, 1 insertions(+), 6 deletions(-)

diff --git a/arch/arm/plat-omap/mcbsp.c b/arch/arm/plat-omap/mcbsp.c
index d883bbf..ac09c79 100644
--- a/arch/arm/plat-omap/mcbsp.c
+++ b/arch/arm/plat-omap/mcbsp.c
@@ -575,8 +575,6 @@ u16 omap_mcbsp_get_fifo_size(unsigned int id)
 }
 EXPORT_SYMBOL(omap_mcbsp_get_fifo_size);
 
-#define MCBSP2_FIFO_SIZE	0x500 /* 1024 + 256 locations */
-#define MCBSP1345_FIFO_SIZE	0x80  /* 128 locations */
 /*
  * omap_mcbsp_get_tx_delay returns the number of used slots in the McBSP FIFO
  */
@@ -595,10 +593,7 @@ u16 omap_mcbsp_get_tx_delay(unsigned int id)
 	buffstat = MCBSP_READ(mcbsp, XBUFFSTAT);
 
 	/* Number of slots are different in McBSP ports */
-	if (mcbsp->id == 2)
-		return MCBSP2_FIFO_SIZE - buffstat;
-	else
-		return MCBSP1345_FIFO_SIZE - buffstat;
+	return mcbsp->pdata->buffer_size - buffstat;
 }
 EXPORT_SYMBOL(omap_mcbsp_get_tx_delay);
 
-- 
1.7.1

[PATCH v5 4/5] ASoC: omap-mcbsp: Save, and use wlen for threshold configuration

[Peter Ujfalusi]

Save the word length configuration of McBSP, and use that information
to calculate, and configure the threshold in McBSP.
Previously the calculation was only correct when the stream had 16bit
audio.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@nokia.com>
Acked-by: Jarkko Nikula <jhnikula@gmail.com>
Acked-by: Mark Brown <broonie@opensource.wolsfonmicro.com>
---
 sound/soc/omap/omap-mcbsp.c |   14 +++++++++-----
 1 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/sound/soc/omap/omap-mcbsp.c b/sound/soc/omap/omap-mcbsp.c
index 6f44cb4..b06d8f1 100644
--- a/sound/soc/omap/omap-mcbsp.c
+++ b/sound/soc/omap/omap-mcbsp.c
@@ -59,6 +59,7 @@ struct omap_mcbsp_data {
 	int				configured;
 	unsigned int			in_freq;
 	int				clk_div;
+	int				wlen;
 };
 
 #define to_mcbsp(priv)	container_of((priv), struct omap_mcbsp_data, bus_id)
@@ -155,19 +156,21 @@ static void omap_mcbsp_set_threshold(struct snd_pcm_substream *substream)
 	struct snd_soc_dai *cpu_dai = rtd->dai->cpu_dai;
 	struct omap_mcbsp_data *mcbsp_data = to_mcbsp(cpu_dai->private_data);
 	int dma_op_mode = omap_mcbsp_get_dma_op_mode(mcbsp_data->bus_id);
-	int samples;
+	int words;
 
 	/* TODO: Currently, MODE_ELEMENT == MODE_FRAME */
 	if (dma_op_mode == MCBSP_DMA_MODE_THRESHOLD)
-		samples = snd_pcm_lib_period_bytes(substream) >> 1;
+		/* The FIFO size depends on the McBSP word configuration */
+		words = snd_pcm_lib_period_bytes(substream) /
+							(mcbsp_data->wlen / 8);
 	else
-		samples = 1;
+		words = 1;
 
 	/* Configure McBSP internal buffer usage */
 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
-		omap_mcbsp_set_tx_threshold(mcbsp_data->bus_id, samples - 1);
+		omap_mcbsp_set_tx_threshold(mcbsp_data->bus_id, words);
 	else
-		omap_mcbsp_set_rx_threshold(mcbsp_data->bus_id, samples - 1);
+		omap_mcbsp_set_rx_threshold(mcbsp_data->bus_id, words);
 }
 
 static int omap_mcbsp_dai_startup(struct snd_pcm_substream *substream,
@@ -409,6 +412,7 @@ static int omap_mcbsp_dai_hw_params(struct snd_pcm_substream *substream,
 	}
 
 	omap_mcbsp_config(bus_id, &mcbsp_data->regs);
+	mcbsp_data->wlen = wlen;
 	mcbsp_data->configured = 1;
 
 	return 0;
-- 
1.7.1

[PATCH v5 5/5] ASoC: omap-mcbsp: Place correct constraints for streams

[Peter Ujfalusi]

OMAP McBSP FIFO is word structured:
McBSP2 has 1024 + 256 = 1280 word long buffer,
McBSP1,3,4,5 has 128 word long buffer

This means, that the size of the FIFO
depends on the McBSP word size configuration.
For example on McBSP3:
16bit samples: size is 128 * 2 = 256 bytes
32bit samples: size is 128 * 4 = 512 bytes
It is simpler to place constraint for buffer and period based on channels.
McBSP3 as example again (16 or 32 bit samples):
1 channel (mono): size is 128 frames (128 words)
2 channels (stereo): size is 128 / 2 = 64 frames (2 * 64 words)
4 channels: size is 128 / 4 = 32 frames (4 * 32 words)

Use the second method to place hw_rule on buffer size, and in threshold
mode to period size.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@nokia.com>
Acked-by: Jarkko Nikula <jhnikula@gmail.com>
Acked-by: Mark Brown <broonie@opensource.wolsfonmicro.com>
---
 sound/soc/omap/omap-mcbsp.c |   98 +++++++++++++++++++++++++++++++++---------
 1 files changed, 77 insertions(+), 21 deletions(-)

diff --git a/sound/soc/omap/omap-mcbsp.c b/sound/soc/omap/omap-mcbsp.c
index b06d8f1..aebd3af 100644
--- a/sound/soc/omap/omap-mcbsp.c
+++ b/sound/soc/omap/omap-mcbsp.c
@@ -173,6 +173,50 @@ static void omap_mcbsp_set_threshold(struct snd_pcm_substream *substream)
 		omap_mcbsp_set_rx_threshold(mcbsp_data->bus_id, words);
 }
 
+static int omap_mcbsp_hwrule_min_buffersize(struct snd_pcm_hw_params *params,
+				    struct snd_pcm_hw_rule *rule)
+{
+	struct snd_interval *buffer_size = hw_param_interval(params,
+					SNDRV_PCM_HW_PARAM_BUFFER_SIZE);
+	struct snd_interval *channels = hw_param_interval(params,
+					SNDRV_PCM_HW_PARAM_CHANNELS);
+	struct omap_mcbsp_data *mcbsp_data = rule->private;
+	struct snd_interval frames;
+	int size;
+
+	snd_interval_any(&frames);
+	size = omap_mcbsp_get_fifo_size(mcbsp_data->bus_id);
+
+	frames.min = size / channels->min;
+	frames.integer = 1;
+	return snd_interval_refine(buffer_size, &frames);
+}
+
+static int omap_mcbsp_hwrule_max_periodsize(struct snd_pcm_hw_params *params,
+				    struct snd_pcm_hw_rule *rule)
+{
+	struct snd_interval *period_size = hw_param_interval(params,
+					SNDRV_PCM_HW_PARAM_PERIOD_SIZE);
+	struct snd_interval *channels = hw_param_interval(params,
+					SNDRV_PCM_HW_PARAM_CHANNELS);
+	struct snd_pcm_substream *substream = rule->private;
+	struct snd_soc_pcm_runtime *rtd = substream->private_data;
+	struct snd_soc_dai *cpu_dai = rtd->dai->cpu_dai;
+	struct omap_mcbsp_data *mcbsp_data = to_mcbsp(cpu_dai->private_data);
+	struct snd_interval frames;
+	int size;
+
+	snd_interval_any(&frames);
+	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
+		size = omap_mcbsp_get_max_tx_threshold(mcbsp_data->bus_id);
+	else
+		size = omap_mcbsp_get_max_rx_threshold(mcbsp_data->bus_id);
+
+	frames.max = size / channels->min;
+	frames.integer = 1;
+	return snd_interval_refine(period_size, &frames);
+}
+
 static int omap_mcbsp_dai_startup(struct snd_pcm_substream *substream,
 				  struct snd_soc_dai *dai)
 {
@@ -185,33 +229,45 @@ static int omap_mcbsp_dai_startup(struct snd_pcm_substream *substream,
 	if (!cpu_dai->active)
 		err = omap_mcbsp_request(bus_id);
 
+	/*
+	 * OMAP3 McBSP FIFO is word structured.
+	 * McBSP2 has 1024 + 256 = 1280 word long buffer,
+	 * McBSP1,3,4,5 has 128 word long buffer
+	 * This means that the size of the FIFO depends on the sample format.
+	 * For example on McBSP3:
+	 * 16bit samples: size is 128 * 2 = 256 bytes
+	 * 32bit samples: size is 128 * 4 = 512 bytes
+	 * It is simpler to place constraint for buffer and period based on
+	 * channels.
+	 * McBSP3 as example again (16 or 32 bit samples):
+	 * 1 channel (mono): size is 128 frames (128 words)
+	 * 2 channels (stereo): size is 128 / 2 = 64 frames (2 * 64 words)
+	 * 4 channels: size is 128 / 4 = 32 frames (4 * 32 words)
+	 */
 	if (cpu_is_omap343x()) {
 		int dma_op_mode = omap_mcbsp_get_dma_op_mode(bus_id);
-		int max_period;
 
 		/*
-		 * McBSP2 in OMAP3 has 1024 * 32-bit internal audio buffer.
-		 * Set constraint for minimum buffer size to the same than FIFO
-		 * size in order to avoid underruns in playback startup because
-		 * HW is keeping the DMA request active until FIFO is filled.
-		 */
-		if (bus_id == 1)
-			snd_pcm_hw_constraint_minmax(substream->runtime,
-					SNDRV_PCM_HW_PARAM_BUFFER_BYTES,
-					4096, UINT_MAX);
-
-		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
-			max_period = omap_mcbsp_get_max_tx_threshold(bus_id);
-		else
-			max_period = omap_mcbsp_get_max_rx_threshold(bus_id);
-
-		max_period++;
-		max_period <<= 1;
+		* The first rule is for the buffer size, we should not allow
+		* smaller buffer than the FIFO size to avoid underruns
+		*/
+		snd_pcm_hw_rule_add(substream->runtime, 0,
+				    SNDRV_PCM_HW_PARAM_CHANNELS,
+				    omap_mcbsp_hwrule_min_buffersize,
+				    mcbsp_data,
+				    SNDRV_PCM_HW_PARAM_BUFFER_SIZE, -1);
 
+		/*
+		 * In case of threshold mode, the rule will ensure, that the
+		 * period size is not bigger than the maximum allowed threshold
+		 * value.
+		 */
 		if (dma_op_mode == MCBSP_DMA_MODE_THRESHOLD)
-			snd_pcm_hw_constraint_minmax(substream->runtime,
-						SNDRV_PCM_HW_PARAM_PERIOD_BYTES,
-						32, max_period);
+			snd_pcm_hw_rule_add(substream->runtime, 0,
+					    SNDRV_PCM_HW_PARAM_CHANNELS,
+					    omap_mcbsp_hwrule_max_periodsize,
+					    substream,
+					    SNDRV_PCM_HW_PARAM_PERIOD_SIZE, -1);
 	}
 
 	return err;
-- 
1.7.1

Re: [PATCH v5 0/5] OMAP/ASoC: McBSP: FIFO handling related fixes

[Tony Lindgren]

* Peter Ujfalusi <peter.ujfalusi@nokia.com> [100603 07:34]:
> Hello,
> 
> Tony: Could you take a look at the arch/arm patches in this series?
> Thanks!
> 
> Changes since v3/4:
> - Fixed commit subjects and messages for OMAP3 related patches
> - Added Acked-by from Mark, and Jarkko

Looks good to me too.

Acked-by: Tony Lindgren <tony@atomide.com>

Re: [PATCH v5 0/5] OMAP/ASoC: McBSP: FIFO handling related fixes

[Liam Girdwood]

On Thu, 2010-06-03 at 07:39 +0300, Peter Ujfalusi wrote:
> Hello,
> 
> Tony: Could you take a look at the arch/arm patches in this series?
> Thanks!
> 
> Changes since v3/4:
> - Fixed commit subjects and messages for OMAP3 related patches
> - Added Acked-by from Mark, and Jarkko
> 
> Intro message from the original series:
> 
> This series aims to correct how the McBSP FIFO is viewed, and handled.
> 
> Introduction of the problem:
> OMAP McBSP FIFO is word structured:
> McBSP2 has 1024 + 256 = 1280 word long buffer,
> McBSP1,3,4,5 has 128 word long buffer
> 
> This means, that the size of the FIFO
> depends on the McBSP word size configuration.
> For example on McBSP3:
> 16bit samples: size is 128 * 2 = 256 bytes
> 32bit samples: size is 128 * 4 = 512 bytes
> It is simpler to place constraint for buffer and period based on channels.
> McBSP3 as example again (16 or 32 bit samples):
> 1 channel (mono): size is 128 frames (128 words)
> 2 channels (stereo): size is 128 / 2 = 64 frames (2 * 64 words)
> 4 channels: size is 128 / 4 = 32 frames (4 * 32 words)
> 
> Since now the McBSP codec supports not only 16bit samples (32biut has been
> recently added), the FIFO size handling is no longer correct, since it has
> been hard wired for 16bit word length.
> 
> The series changes how the users of McBSP are configuring the FIFO:
> It used to be 0 based (0 meant 1 word threshold). After this series users can
> configure the threshold in 1 base mode (1 means 1 word threshold).
> The platform code now provides the full size of the FIFO in words, instead of
> the already limited value used in the past.
> 
> In ASoC omap-mcbsp code hw_rule based constraint refinement is going to be used
> instead of the hardwired static constraint, which was correct only in case of
> 16bit word length.
> 
> The hw_rule is refining the minimum buffer size based on the channel number
> going to be used by the coming stream.
> In case of threshold mode additional hw_rule refines the maximum allowed period
> size.
> 
> The series are generated agains Takashi's sound-2.6: topic/asoc branch.
> 
> CCing also Eduardo, and Eero since they have worked on the original
> FIFO/threshold implementation.
> 
> All commetns and testers are welcome!
> Peter
> 
> ---
> Peter Ujfalusi (5):
>   OMAP: McBSP: Function to query the FIFO size
>   OMAP3: McBSP: Change the way how the FIFO is handled
>   OMAP3: McBSP: Use the port's buffer_size when calculating tx delay
>   ASoC: omap-mcbsp: Save, and use wlen for threshold configuration
>   ASoC: omap-mcbsp: Place correct constraints for streams
> 
>  arch/arm/mach-omap2/mcbsp.c             |   10 ++--
>  arch/arm/plat-omap/include/plat/mcbsp.h |    2 +
>  arch/arm/plat-omap/mcbsp.c              |   51 ++++++++++-----
>  sound/soc/omap/omap-mcbsp.c             |  112 +++++++++++++++++++++++-------
>  4 files changed, 128 insertions(+), 47 deletions(-)
> 

Applied all.

Thanks

Liam
-- 
Freelance Developer, SlimLogic Ltd
ASoC and Voltage Regulator Maintainer.
http://www.slimlogic.co.uk