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ASoC: fsl_asrc_dma: Fix warning "Cannot create DMA dma:tx symlink"
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The issue log is:

[   48.021506] CPU: 0 PID: 664 Comm: aplay Not tainted 5.7.0-rc1-13120-g12b434cbbea0 torvalds#343
[   48.031063] Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree)
[   48.037638] [<c0110dd8>] (unwind_backtrace) from [<c010b8ec>] (show_stack+0x10/0x14)
[   48.045413] [<c010b8ec>] (show_stack) from [<c0557fc0>] (dump_stack+0xe4/0x118)
[   48.052757] [<c0557fc0>] (dump_stack) from [<c032aeb4>] (sysfs_warn_dup+0x50/0x64)
[   48.060357] [<c032aeb4>] (sysfs_warn_dup) from [<c032b1a8>] (sysfs_do_create_link_sd+0xc8/0xd4)
[   48.069086] [<c032b1a8>] (sysfs_do_create_link_sd) from [<c05dc668>] (dma_request_chan+0xb0/0x210)
[   48.078068] [<c05dc668>] (dma_request_chan) from [<c05dc7d0>] (dma_request_slave_channel+0x8/0x14)
[   48.087060] [<c05dc7d0>] (dma_request_slave_channel) from [<c09d5cd4>] (fsl_asrc_dma_hw_params+0x1dc/0x434)
[   48.096831] [<c09d5cd4>] (fsl_asrc_dma_hw_params) from [<c09c143c>] (soc_pcm_hw_params+0x4b0/0x650)
[   48.105903] [<c09c143c>] (soc_pcm_hw_params) from [<c09c36a8>] (dpcm_fe_dai_hw_params+0x70/0xe4)
[   48.114715] [<c09c36a8>] (dpcm_fe_dai_hw_params) from [<c099b274>] (snd_pcm_hw_params+0x158/0x418)
[   48.123701] [<c099b274>] (snd_pcm_hw_params) from [<c099c5a0>] (snd_pcm_ioctl+0x734/0x183c)
[   48.132079] [<c099c5a0>] (snd_pcm_ioctl) from [<c029ff94>] (ksys_ioctl+0x2ac/0xb98)
[   48.139765] [<c029ff94>] (ksys_ioctl) from [<c0100080>] (ret_fast_syscall+0x0/0x28)
[   48.147440] Exception stack(0xed3c5fa8 to 0xed3c5ff0)
[   48.152515] 5fa0:                   bec28670 00e92870 00000004 c25c4111 bec28670 0002000f
[   48.160716] 5fc0: bec28670 00e92870 00e92820 00000036 0000bb80 00000000 0002c2f8 00000003
[   48.168913] 5fe0: b6f4d3fc bec2853c b6ee7655 b6e22cf8
[   48.174236] fsl-esai-dai 2024000.esai: Cannot create DMA dma:tx symlink

The dma channel is already requested by Back-End cpu dai driver,
if fsl_asrc_dma requests dma chan with same dma:tx symlink, then
this warning comes out.

The warning is added by
commit 71723a9 ("dmaengine: Create symlinks between DMA channels and slaves")
commit bad8356 ("dmaengine: Cleanups for the slave <-> channel symlink support")

As the dma channel is requested by Back-End, we need to reuse the channel
and avoid to request a new one, then the issue can be fixed.

In order to get the dma channel which is already requested in Back-End.
we export two functions (snd_soc_lookup_component_nolocked and
soc_component_to_pcm), if we can get the dma channel, then reuse it.
if can't, then request a new one.

Signed-off-by: Shengjiu Wang <[email protected]>
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@TE-N-ShengjiuWang @intel-lab-lkp
TE-N-ShengjiuWang authored and intel-lab-lkp committed Jun 8, 2020
1 parent 1dd9cd7 commit 9d8ec10
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Showing 6 changed files with 55 additions and 24 deletions.
11 changes: 11 additions & 0 deletions include/sound/dmaengine_pcm.h
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Original file line number Diff line number Diff line change
Expand Up @@ -161,4 +161,15 @@ int snd_dmaengine_pcm_prepare_slave_config(struct snd_pcm_substream *substream,

#define SND_DMAENGINE_PCM_DRV_NAME "snd_dmaengine_pcm"

struct dmaengine_pcm {
struct dma_chan *chan[SNDRV_PCM_STREAM_LAST + 1];
const struct snd_dmaengine_pcm_config *config;
struct snd_soc_component component;
unsigned int flags;
};

static inline struct dmaengine_pcm *soc_component_to_pcm(struct snd_soc_component *p)
{
return container_of(p, struct dmaengine_pcm, component);
}
#endif
2 changes: 2 additions & 0 deletions include/sound/soc.h
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Original file line number Diff line number Diff line change
Expand Up @@ -444,6 +444,8 @@ int devm_snd_soc_register_component(struct device *dev,
const struct snd_soc_component_driver *component_driver,
struct snd_soc_dai_driver *dai_drv, int num_dai);
void snd_soc_unregister_component(struct device *dev);
struct snd_soc_component *snd_soc_lookup_component_nolocked(struct device *dev,
const char *driver_name);
struct snd_soc_component *snd_soc_lookup_component(struct device *dev,
const char *driver_name);

Expand Down
2 changes: 2 additions & 0 deletions sound/soc/fsl/fsl_asrc_common.h
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Original file line number Diff line number Diff line change
Expand Up @@ -32,6 +32,7 @@ enum asrc_pair_index {
* @dma_chan: inputer and output DMA channels
* @dma_data: private dma data
* @pos: hardware pointer position
* @req_dma_chan_dev_to_dev: flag for release dev_to_dev chan
* @private: pair private area
*/
struct fsl_asrc_pair {
Expand All @@ -45,6 +46,7 @@ struct fsl_asrc_pair {
struct dma_chan *dma_chan[2];
struct imx_dma_data dma_data;
unsigned int pos;
bool req_dma_chan_dev_to_dev;

void *private;
};
Expand Down
49 changes: 38 additions & 11 deletions sound/soc/fsl/fsl_asrc_dma.c
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Original file line number Diff line number Diff line change
Expand Up @@ -135,14 +135,15 @@ static int fsl_asrc_dma_hw_params(struct snd_soc_component *component,
struct snd_dmaengine_dai_dma_data *dma_params_be = NULL;
struct snd_pcm_runtime *runtime = substream->runtime;
struct fsl_asrc_pair *pair = runtime->private_data;
struct snd_soc_component *component_be = NULL;
struct fsl_asrc *asrc = pair->asrc;
struct dma_slave_config config_fe, config_be;
enum asrc_pair_index index = pair->index;
struct device *dev = component->dev;
int stream = substream->stream;
struct imx_dma_data *tmp_data;
struct snd_soc_dpcm *dpcm;
struct dma_chan *tmp_chan;
struct dma_chan *tmp_chan = NULL, *tmp_chan_new = NULL;
struct device *dev_be;
u8 dir = tx ? OUT : IN;
dma_cap_mask_t mask;
Expand All @@ -160,6 +161,7 @@ static int fsl_asrc_dma_hw_params(struct snd_soc_component *component,
substream_be = snd_soc_dpcm_get_substream(be, stream);
dma_params_be = snd_soc_dai_get_dma_data(dai, substream_be);
dev_be = dai->dev;
component_be = snd_soc_lookup_component_nolocked(dev_be, SND_DMAENGINE_PCM_DRV_NAME);
break;
}

Expand Down Expand Up @@ -205,10 +207,16 @@ static int fsl_asrc_dma_hw_params(struct snd_soc_component *component,
*/
if (!asrc->use_edma) {
/* Get DMA request of Back-End */
tmp_chan = dma_request_slave_channel(dev_be, tx ? "tx" : "rx");
if (component_be)
tmp_chan = soc_component_to_pcm(component_be)->chan[substream->stream];
if (!tmp_chan) {
tmp_chan_new = dma_request_slave_channel(dev_be, tx ? "tx" : "rx");
tmp_chan = tmp_chan_new;
}
tmp_data = tmp_chan->private;
pair->dma_data.dma_request = tmp_data->dma_request;
dma_release_channel(tmp_chan);
if (tmp_chan_new)
dma_release_channel(tmp_chan_new);

/* Get DMA request of Front-End */
tmp_chan = asrc->get_dma_channel(pair, dir);
Expand All @@ -220,9 +228,26 @@ static int fsl_asrc_dma_hw_params(struct snd_soc_component *component,

pair->dma_chan[dir] =
dma_request_channel(mask, filter, &pair->dma_data);
pair->req_dma_chan_dev_to_dev = true;
} else {
pair->dma_chan[dir] =
asrc->get_dma_channel(pair, dir);
/* With EDMA, there is two dma channels can be used for p2p,
* one is from ASRC, one is from another peripheral
* (ESAI or SAI) previously we select the dma channel of ASRC,
* but find an issue for ideal ratio case, there is no control
* for data copy speed, the speed is faster than sample
* frequency.
*
* So we switch to dma channel of peripheral (ESAI or SAI),
* that copy speed of DMA is controlled by data consumption
* speed in the peripheral FIFO.
*/
pair->req_dma_chan_dev_to_dev = false;
if (component_be)
pair->dma_chan[dir] = soc_component_to_pcm(component_be)->chan[substream->stream];;
if (!pair->dma_chan[dir]) {
pair->dma_chan[dir] = dma_request_slave_channel(dev_be, tx ? "tx" : "rx");
pair->req_dma_chan_dev_to_dev = true;
}
}

if (!pair->dma_chan[dir]) {
Expand Down Expand Up @@ -273,19 +298,21 @@ static int fsl_asrc_dma_hw_params(struct snd_soc_component *component,
static int fsl_asrc_dma_hw_free(struct snd_soc_component *component,
struct snd_pcm_substream *substream)
{
bool tx = substream->stream == SNDRV_PCM_STREAM_PLAYBACK;
struct snd_pcm_runtime *runtime = substream->runtime;
struct fsl_asrc_pair *pair = runtime->private_data;
u8 dir = tx ? OUT : IN;

snd_pcm_set_runtime_buffer(substream, NULL);

if (pair->dma_chan[IN])
dma_release_channel(pair->dma_chan[IN]);
if (pair->dma_chan[!dir])
dma_release_channel(pair->dma_chan[!dir]);

if (pair->dma_chan[OUT])
dma_release_channel(pair->dma_chan[OUT]);
if (pair->dma_chan[dir] && pair->req_dma_chan_dev_to_dev)
dma_release_channel(pair->dma_chan[dir]);

pair->dma_chan[IN] = NULL;
pair->dma_chan[OUT] = NULL;
pair->dma_chan[!dir] = NULL;
pair->dma_chan[dir] = NULL;

return 0;
}
Expand Down
3 changes: 2 additions & 1 deletion sound/soc/soc-core.c
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Original file line number Diff line number Diff line change
Expand Up @@ -310,7 +310,7 @@ struct snd_soc_component *snd_soc_rtdcom_lookup(struct snd_soc_pcm_runtime *rtd,
}
EXPORT_SYMBOL_GPL(snd_soc_rtdcom_lookup);

static struct snd_soc_component
struct snd_soc_component
*snd_soc_lookup_component_nolocked(struct device *dev, const char *driver_name)
{
struct snd_soc_component *component;
Expand All @@ -329,6 +329,7 @@ static struct snd_soc_component

return found_component;
}
EXPORT_SYMBOL_GPL(snd_soc_lookup_component_nolocked);

struct snd_soc_component *snd_soc_lookup_component(struct device *dev,
const char *driver_name)
Expand Down
12 changes: 0 additions & 12 deletions sound/soc/soc-generic-dmaengine-pcm.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -21,18 +21,6 @@
*/
#define SND_DMAENGINE_PCM_FLAG_NO_RESIDUE BIT(31)

struct dmaengine_pcm {
struct dma_chan *chan[SNDRV_PCM_STREAM_LAST + 1];
const struct snd_dmaengine_pcm_config *config;
struct snd_soc_component component;
unsigned int flags;
};

static struct dmaengine_pcm *soc_component_to_pcm(struct snd_soc_component *p)
{
return container_of(p, struct dmaengine_pcm, component);
}

static struct device *dmaengine_dma_dev(struct dmaengine_pcm *pcm,
struct snd_pcm_substream *substream)
{
Expand Down

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