ASoC: dmaengine-pcm: Rename and deprecate snd_dmaengine_pcm_pointer

Currently the sound dmaengine pcm helper functions implement the pcm_pointer
callback by trying to count the number of elapsed periods. This is done by
advancing the stream position in the dmaengine callback by one period.
Unfortunately there is no guarantee that the callback will be called for each
elapsed period. It may be possible that under high system load it is only called
once for multiple elapsed periods. This patch renames the current implementation
and documents its shortcomings and that it should not be used anymore in new
drivers.

The next patch will introduce a new snd_dmaengine_pcm_pointer which will be
implemented based on querying the current stream position from the dma device.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by Vinod Koul <vinod.koul@linux.intel.com>
Acked-by: Dong Aisheng <dong.aisheng@linaro.org
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

diff --git a/include/sound/dmaengine_pcm.h b/include/sound/dmaengine_pcm.h
index a8fcaa6d531f7caf21fd32398e55ad4b2a140a26..ea5791583fedb5b873ebfc7733212d29f1b0768e 100644 (file)
--- a/include/sound/dmaengine_pcm.h
+++ b/include/sound/dmaengine_pcm.h
@@ -38,7 +38,7 @@ void *snd_dmaengine_pcm_get_data(struct snd_pcm_substream *substream);
 int snd_hwparams_to_dma_slave_config(const struct snd_pcm_substream *substream,
        const struct snd_pcm_hw_params *params, struct dma_slave_config *slave_config);
 int snd_dmaengine_pcm_trigger(struct snd_pcm_substream *substream, int cmd);
-snd_pcm_uframes_t snd_dmaengine_pcm_pointer(struct snd_pcm_substream *substream);
+snd_pcm_uframes_t snd_dmaengine_pcm_pointer_no_residue(struct snd_pcm_substream *substream);
 
 int snd_dmaengine_pcm_open(struct snd_pcm_substream *substream,
        dma_filter_fn filter_fn, void *filter_data);

diff --git a/sound/soc/ep93xx/ep93xx-pcm.c b/sound/soc/ep93xx/ep93xx-pcm.c
index 162dbb74f4cca6ce793f292fb1dacf7aeaddac97..4eea98b42bc8389de50e64b34d9ea2e9f65f586e 100644 (file)
--- a/sound/soc/ep93xx/ep93xx-pcm.c
+++ b/sound/soc/ep93xx/ep93xx-pcm.c
@@ -136,7 +136,7 @@ static struct snd_pcm_ops ep93xx_pcm_ops = {
        .hw_params      = ep93xx_pcm_hw_params,
        .hw_free        = ep93xx_pcm_hw_free,
        .trigger        = snd_dmaengine_pcm_trigger,
-       .pointer        = snd_dmaengine_pcm_pointer,
+       .pointer        = snd_dmaengine_pcm_pointer_no_residue,
        .mmap           = ep93xx_pcm_mmap,
 };
 

diff --git a/sound/soc/fsl/imx-pcm-dma.c b/sound/soc/fsl/imx-pcm-dma.c
index f3c0a5ef35c8afc08a2fb8c48775285985ec421d..48f9d886f0205a8b0255e93935ce44f3c5ff6f1e 100644 (file)
--- a/sound/soc/fsl/imx-pcm-dma.c
+++ b/sound/soc/fsl/imx-pcm-dma.c
@@ -141,7 +141,7 @@ static struct snd_pcm_ops imx_pcm_ops = {
        .ioctl          = snd_pcm_lib_ioctl,
        .hw_params      = snd_imx_pcm_hw_params,
        .trigger        = snd_dmaengine_pcm_trigger,
-       .pointer        = snd_dmaengine_pcm_pointer,
+       .pointer        = snd_dmaengine_pcm_pointer_no_residue,
        .mmap           = snd_imx_pcm_mmap,
 };
 

diff --git a/sound/soc/mxs/mxs-pcm.c b/sound/soc/mxs/mxs-pcm.c
index 373dec90579f5e7860e4dbeab8e00645942eb648..f82d766cbf9eb7ecd5ddd7cea788781d07b7af86 100644 (file)
--- a/sound/soc/mxs/mxs-pcm.c
+++ b/sound/soc/mxs/mxs-pcm.c
@@ -141,7 +141,7 @@ static struct snd_pcm_ops mxs_pcm_ops = {
        .ioctl          = snd_pcm_lib_ioctl,
        .hw_params      = snd_mxs_pcm_hw_params,
        .trigger        = snd_dmaengine_pcm_trigger,
-       .pointer        = snd_dmaengine_pcm_pointer,
+       .pointer        = snd_dmaengine_pcm_pointer_no_residue,
        .mmap           = snd_mxs_pcm_mmap,
 };
 

diff --git a/sound/soc/soc-dmaengine-pcm.c b/sound/soc/soc-dmaengine-pcm.c
index 475695234b3d2f37d843e34e2c3e8caa4df0b4c7..7c0877e3731c41c21b4e4195d90b82cfef1119a9 100644 (file)
--- a/sound/soc/soc-dmaengine-pcm.c
+++ b/sound/soc/soc-dmaengine-pcm.c
@@ -200,18 +200,18 @@ int snd_dmaengine_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
 EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_trigger);
 
 /**
- * snd_dmaengine_pcm_pointer - dmaengine based PCM pointer implementation
+ * snd_dmaengine_pcm_pointer_no_residue - dmaengine based PCM pointer implementation
  * @substream: PCM substream
  *
- * This function can be used as the PCM pointer callback for dmaengine based PCM
- * driver implementations.
+ * This function is deprecated and should not be used by new drivers, as its
+ * results may be unreliable.
  */
-snd_pcm_uframes_t snd_dmaengine_pcm_pointer(struct snd_pcm_substream *substream)
+snd_pcm_uframes_t snd_dmaengine_pcm_pointer_no_residue(struct snd_pcm_substream *substream)
 {
        struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
        return bytes_to_frames(substream->runtime, prtd->pos);
 }
-EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_pointer);
+EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_pointer_no_residue);
 
 static int dmaengine_pcm_request_channel(struct dmaengine_pcm_runtime_data *prtd,
        dma_filter_fn filter_fn, void *filter_data)

diff --git a/sound/soc/ux500/ux500_pcm.c b/sound/soc/ux500/ux500_pcm.c
index 97d8e4de29c219e50390e2f4dd097369d498517d..1a04e248453c6fb743b7fb765d1ad1eeaa55cd39 100644 (file)
--- a/sound/soc/ux500/ux500_pcm.c
+++ b/sound/soc/ux500/ux500_pcm.c
@@ -261,7 +261,7 @@ static struct snd_pcm_ops ux500_pcm_ops = {
        .hw_params      = ux500_pcm_hw_params,
        .hw_free        = ux500_pcm_hw_free,
        .trigger        = snd_dmaengine_pcm_trigger,
-       .pointer        = snd_dmaengine_pcm_pointer,
+       .pointer        = snd_dmaengine_pcm_pointer_no_residue,
        .mmap           = ux500_pcm_mmap
 };