[alsa-devel] [PATCH 2.6.30] ASoC: optimize init sequence of Freescale MPC8610 sound drivers
Timur Tabi
timur at freescale.com
Fri Feb 6 00:56:02 CET 2009
In the Freescale MPC8610 sound drivers, relocate all code from the _prepare
functions into the corresponding _hw_params functions. These drivers assumed
that the sample size is known in the _prepare function and not in the
_hw_params function, but this is not true.
Move the code in fsl_dma_prepare() into fsl_dma_hw_param(). Create
fsl_ssi_hw_params() and move the code from fsl_ssi_prepare() into it.
Turn off snooping for DMA operations to/from I/O registers, since that's not
necessary.
Signed-off-by: Timur Tabi <timur at freescale.com>
---
sound/soc/fsl/fsl_dma.c | 178 ++++++++++++++++++++++------------------------
sound/soc/fsl/fsl_ssi.c | 19 +++---
2 files changed, 94 insertions(+), 103 deletions(-)
diff --git a/sound/soc/fsl/fsl_dma.c b/sound/soc/fsl/fsl_dma.c
index 64993ed..58a3fa4 100644
--- a/sound/soc/fsl/fsl_dma.c
+++ b/sound/soc/fsl/fsl_dma.c
@@ -464,11 +464,7 @@ static int fsl_dma_open(struct snd_pcm_substream *substream)
sizeof(struct fsl_dma_link_descriptor);
for (i = 0; i < NUM_DMA_LINKS; i++) {
- struct fsl_dma_link_descriptor *link = &dma_private->link[i];
-
- link->source_attr = cpu_to_be32(CCSR_DMA_ATR_SNOOP);
- link->dest_attr = cpu_to_be32(CCSR_DMA_ATR_SNOOP);
- link->next = cpu_to_be64(temp_link);
+ dma_private->link[i].next = cpu_to_be64(temp_link);
temp_link += sizeof(struct fsl_dma_link_descriptor);
}
@@ -525,79 +521,9 @@ static int fsl_dma_open(struct snd_pcm_substream *substream)
* This function obtains hardware parameters about the opened stream and
* programs the DMA controller accordingly.
*
- * Note that due to a quirk of the SSI's STX register, the target address
- * for the DMA operations depends on the sample size. So we don't program
- * the dest_addr (for playback -- source_addr for capture) fields in the
- * link descriptors here. We do that in fsl_dma_prepare()
- */
-static int fsl_dma_hw_params(struct snd_pcm_substream *substream,
- struct snd_pcm_hw_params *hw_params)
-{
- struct snd_pcm_runtime *runtime = substream->runtime;
- struct fsl_dma_private *dma_private = runtime->private_data;
-
- dma_addr_t temp_addr; /* Pointer to next period */
-
- unsigned int i;
-
- /* Get all the parameters we need */
- size_t buffer_size = params_buffer_bytes(hw_params);
- size_t period_size = params_period_bytes(hw_params);
-
- /* Initialize our DMA tracking variables */
- dma_private->period_size = period_size;
- dma_private->num_periods = params_periods(hw_params);
- dma_private->dma_buf_end = dma_private->dma_buf_phys + buffer_size;
- dma_private->dma_buf_next = dma_private->dma_buf_phys +
- (NUM_DMA_LINKS * period_size);
- if (dma_private->dma_buf_next >= dma_private->dma_buf_end)
- dma_private->dma_buf_next = dma_private->dma_buf_phys;
-
- /*
- * The actual address in STX0 (destination for playback, source for
- * capture) is based on the sample size, but we don't know the sample
- * size in this function, so we'll have to adjust that later. See
- * comments in fsl_dma_prepare().
- *
- * The DMA controller does not have a cache, so the CPU does not
- * need to tell it to flush its cache. However, the DMA
- * controller does need to tell the CPU to flush its cache.
- * That's what the SNOOP bit does.
- *
- * Also, even though the DMA controller supports 36-bit addressing, for
- * simplicity we currently support only 32-bit addresses for the audio
- * buffer itself.
- */
- temp_addr = substream->dma_buffer.addr;
-
- for (i = 0; i < NUM_DMA_LINKS; i++) {
- struct fsl_dma_link_descriptor *link = &dma_private->link[i];
-
- link->count = cpu_to_be32(period_size);
-
- if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
- link->source_addr = cpu_to_be32(temp_addr);
- else
- link->dest_addr = cpu_to_be32(temp_addr);
-
- temp_addr += period_size;
- }
-
- return 0;
-}
-
-/**
- * fsl_dma_prepare - prepare the DMA registers for playback.
- *
- * This function is called after the specifics of the audio data are known,
- * i.e. snd_pcm_runtime is initialized.
- *
- * In this function, we finish programming the registers of the DMA
- * controller that are dependent on the sample size.
- *
- * One of the drawbacks with big-endian is that when copying integers of
- * different sizes to a fixed-sized register, the address to which the
- * integer must be copied is dependent on the size of the integer.
+ * One drawback of big-endian is that when copying integers of different
+ * sizes to a fixed-sized register, the address to which the integer must be
+ * copied is dependent on the size of the integer.
*
* For example, if P is the address of a 32-bit register, and X is a 32-bit
* integer, then X should be copied to address P. However, if X is a 16-bit
@@ -613,22 +539,58 @@ static int fsl_dma_hw_params(struct snd_pcm_substream *substream,
* and 8 bytes at a time). So we do not support packed 24-bit samples.
* 24-bit data must be padded to 32 bits.
*/
-static int fsl_dma_prepare(struct snd_pcm_substream *substream)
+static int fsl_dma_hw_params(struct snd_pcm_substream *substream,
+ struct snd_pcm_hw_params *hw_params)
{
struct snd_pcm_runtime *runtime = substream->runtime;
struct fsl_dma_private *dma_private = runtime->private_data;
+
+ /* Number of bits per sample */
+ unsigned int sample_size =
+ snd_pcm_format_physical_width(params_format(hw_params));
+
+ /* Number of bytes per frame */
+ unsigned int frame_size = 2 * (sample_size / 8);
+
+ /* Bus address of SSI STX register */
+ dma_addr_t ssi_sxx_phys = dma_private->ssi_sxx_phys;
+
+ /* Size of the DMA buffer, in bytes */
+ size_t buffer_size = params_buffer_bytes(hw_params);
+
+ /* Number of bytes per period */
+ size_t period_size = params_period_bytes(hw_params);
+
+ /* Pointer to next period */
+ dma_addr_t temp_addr = substream->dma_buffer.addr;
+
+ /* Pointer to DMA controller */
struct ccsr_dma_channel __iomem *dma_channel = dma_private->dma_channel;
- u32 mr;
+
+ u32 mr; /* DMA Mode Register */
+
unsigned int i;
- dma_addr_t ssi_sxx_phys; /* Bus address of SSI STX register */
- unsigned int frame_size; /* Number of bytes per frame */
- ssi_sxx_phys = dma_private->ssi_sxx_phys;
+ /* Initialize our DMA tracking variables */
+ dma_private->period_size = period_size;
+ dma_private->num_periods = params_periods(hw_params);
+ dma_private->dma_buf_end = dma_private->dma_buf_phys + buffer_size;
+ dma_private->dma_buf_next = dma_private->dma_buf_phys +
+ (NUM_DMA_LINKS * period_size);
+
+ if (dma_private->dma_buf_next >= dma_private->dma_buf_end)
+ /* This happens if the number of periods == NUM_DMA_LINKS */
+ dma_private->dma_buf_next = dma_private->dma_buf_phys;
mr = in_be32(&dma_channel->mr) & ~(CCSR_DMA_MR_BWC_MASK |
CCSR_DMA_MR_SAHTS_MASK | CCSR_DMA_MR_DAHTS_MASK);
- switch (runtime->sample_bits) {
+ /* Due to a quirk of the SSI's STX register, the target address
+ * for the DMA operations depends on the sample size. So we calculate
+ * that offset here. While we're at it, also tell the DMA controller
+ * how much data to transfer per sample.
+ */
+ switch (sample_size) {
case 8:
mr |= CCSR_DMA_MR_DAHTS_1 | CCSR_DMA_MR_SAHTS_1;
ssi_sxx_phys += 3;
@@ -641,12 +603,12 @@ static int fsl_dma_prepare(struct snd_pcm_substream *substream)
mr |= CCSR_DMA_MR_DAHTS_4 | CCSR_DMA_MR_SAHTS_4;
break;
default:
+ /* We should never get here */
dev_err(substream->pcm->card->dev,
- "unsupported sample size %u\n", runtime->sample_bits);
+ "unsupported sample size %u\n", sample_size);
return -EINVAL;
}
- frame_size = runtime->frame_bits / 8;
/*
* BWC should always be a multiple of the frame size. BWC determines
* how many bytes are sent/received before the DMA controller checks the
@@ -655,7 +617,6 @@ static int fsl_dma_prepare(struct snd_pcm_substream *substream)
* capture, the receive FIFO is triggered when it contains one frame, so
* we want to receive one frame at a time.
*/
-
if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
mr |= CCSR_DMA_MR_BWC(2 * frame_size);
else
@@ -663,16 +624,48 @@ static int fsl_dma_prepare(struct snd_pcm_substream *substream)
out_be32(&dma_channel->mr, mr);
- /*
- * Program the address of the DMA transfer to/from the SSI.
- */
for (i = 0; i < NUM_DMA_LINKS; i++) {
struct fsl_dma_link_descriptor *link = &dma_private->link[i];
- if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
+ link->count = cpu_to_be32(period_size);
+
+ /* Even though the DMA controller supports 36-bit addressing,
+ * for simplicity we allow only 32-bit addresses for the audio
+ * buffer itself. This was enforced in fsl_dma_new() with the
+ * DMA mask.
+ *
+ * The snoop bit tells the DMA controller whether it should tell
+ * the ECM to snoop during a read or write to an address. For
+ * audio, we use DMA to transfer data between memory and an I/O
+ * device (the SSI's STX0 or SRX0 register). Snooping is only
+ * needed if there is a cache, so we need to snoop memory
+ * addresses only. For playback, that means we snoop the source
+ * but not the destination. For capture, we snoop the
+ * destination but not the source.
+ *
+ * Note that failing to snoop properly is unlikely to cause
+ * cache incoherency if the period size is larger than the
+ * size of L1 cache. This is because filling in one period will
+ * flush out the data for the previous period. So if you
+ * increased period_bytes_min to a large enough size, you might
+ * get more performance by not snooping, and you'll still be
+ * okay.
+ */
+ if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
+ link->source_addr = cpu_to_be32(temp_addr);
+ link->source_attr = cpu_to_be32(CCSR_DMA_ATR_SNOOP);
+
link->dest_addr = cpu_to_be32(ssi_sxx_phys);
- else
+ link->dest_attr = cpu_to_be32(CCSR_DMA_ATR_NOSNOOP);
+ } else {
link->source_addr = cpu_to_be32(ssi_sxx_phys);
+ link->source_attr = cpu_to_be32(CCSR_DMA_ATR_NOSNOOP);
+
+ link->dest_addr = cpu_to_be32(temp_addr);
+ link->dest_attr = cpu_to_be32(CCSR_DMA_ATR_SNOOP);
+ }
+
+ temp_addr += period_size;
}
return 0;
@@ -808,7 +801,6 @@ static struct snd_pcm_ops fsl_dma_ops = {
.ioctl = snd_pcm_lib_ioctl,
.hw_params = fsl_dma_hw_params,
.hw_free = fsl_dma_hw_free,
- .prepare = fsl_dma_prepare,
.pointer = fsl_dma_pointer,
};
diff --git a/sound/soc/fsl/fsl_ssi.c b/sound/soc/fsl/fsl_ssi.c
index c6d6eb7..6844009 100644
--- a/sound/soc/fsl/fsl_ssi.c
+++ b/sound/soc/fsl/fsl_ssi.c
@@ -400,7 +400,7 @@ static int fsl_ssi_startup(struct snd_pcm_substream *substream,
}
/**
- * fsl_ssi_prepare: prepare the SSI.
+ * fsl_ssi_hw_params - program the sample size
*
* Most of the SSI registers have been programmed in the startup function,
* but the word length must be programmed here. Unfortunately, programming
@@ -412,20 +412,19 @@ static int fsl_ssi_startup(struct snd_pcm_substream *substream,
* Note: The SxCCR.DC and SxCCR.PM bits are only used if the SSI is the
* clock master.
*/
-static int fsl_ssi_prepare(struct snd_pcm_substream *substream,
- struct snd_soc_dai *dai)
+static int fsl_ssi_hw_params(struct snd_pcm_substream *substream,
+ struct snd_pcm_hw_params *hw_params, struct snd_soc_dai *cpu_dai)
{
- struct snd_pcm_runtime *runtime = substream->runtime;
- struct snd_soc_pcm_runtime *rtd = substream->private_data;
- struct fsl_ssi_private *ssi_private = rtd->dai->cpu_dai->private_data;
-
- struct ccsr_ssi __iomem *ssi = ssi_private->ssi;
+ struct fsl_ssi_private *ssi_private = cpu_dai->private_data;
if (substream == ssi_private->first_stream) {
+ struct ccsr_ssi __iomem *ssi = ssi_private->ssi;
+ unsigned int sample_size =
+ snd_pcm_format_width(params_format(hw_params));
u32 wl;
/* The SSI should always be disabled at this points (SSIEN=0) */
- wl = CCSR_SSI_SxCCR_WL(snd_pcm_format_width(runtime->format));
+ wl = CCSR_SSI_SxCCR_WL(sample_size);
/* In synchronous mode, the SSI uses STCCR for capture */
clrsetbits_be32(&ssi->stccr, CCSR_SSI_SxCCR_WL_MASK, wl);
@@ -579,7 +578,7 @@ static struct snd_soc_dai fsl_ssi_dai_template = {
},
.ops = {
.startup = fsl_ssi_startup,
- .prepare = fsl_ssi_prepare,
+ .hw_params = fsl_ssi_hw_params,
.shutdown = fsl_ssi_shutdown,
.trigger = fsl_ssi_trigger,
.set_sysclk = fsl_ssi_set_sysclk,
--
1.5.5
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