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ASoC: apple: mca: Add locking

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In DAI ops, accesses to the native cluster (of the DAI), and to data of
clusters related to it by a DPCM frontend-backend link, should have
been synchronized by the 'pcm_mutex' lock at ASoC level.

What is not covered are the 'port_driver' accesses on foreign clusters
to which the current cluster has no a priori relation, so fill in
locking for that. (This should only matter in bizarre configurations of
sharing one MCA peripheral between ASoC cards.)

Signed-off-by: Martin Povišer <povik+lin@cutebit.org>
Link: https://lore.kernel.org/r/20220824160715.95779-5-povik+lin@cutebit.org
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Martin Povišer 2022-08-24 18:07:15 +02:00 committed by Mark Brown
parent 3df5d0d972
commit 4065f0b25b
No known key found for this signature in database
GPG key ID: 24D68B725D5487D0
1 changed files with 21 additions and 2 deletions
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23
sound/soc/apple/mca.c
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@ -158,6 +158,9 @@ struct mca_data {
struct reset_control *rstc;
struct device_link *pd_link;
/* Mutex for accessing port_driver of foreign clusters */
struct mutex port_mutex;
int nclusters;
struct mca_cluster clusters[];
};
@ -296,16 +299,21 @@ static bool mca_fe_clocks_in_use(struct mca_cluster *cl)
struct mca_cluster *be_cl;
int stream, i;
mutex_lock(&mca->port_mutex);
for (i = 0; i < mca->nclusters; i++) {
be_cl = &mca->clusters[i];
if (be_cl->port_driver != cl->no)
continue;
for_each_pcm_streams(stream)
if (be_cl->clocks_in_use[stream])
for_each_pcm_streams(stream) {
if (be_cl->clocks_in_use[stream]) {
mutex_unlock(&mca->port_mutex);
return true;
}
}
}
mutex_unlock(&mca->port_mutex);
return false;
}
@ -349,6 +357,11 @@ static int mca_be_hw_free(struct snd_pcm_substream *substream,
if (cl->port_driver < 0)
return -EINVAL;
/*
* We are operating on a foreign cluster here, but since we
* belong to the same PCM, accesses should have been
* synchronized at ASoC level.
*/
fe_cl = &mca->clusters[cl->port_driver];
if (!mca_fe_clocks_in_use(fe_cl))
return 0; /* Nothing to do */
@ -721,7 +734,9 @@ static int mca_be_startup(struct snd_pcm_substream *substream,
cl->base + REG_PORT_CLOCK_SEL);
writel_relaxed(PORT_DATA_SEL_TXA(fe_cl->no),
cl->base + REG_PORT_DATA_SEL);
mutex_lock(&mca->port_mutex);
cl->port_driver = fe_cl->no;
mutex_unlock(&mca->port_mutex);
cl->port_started[substream->stream] = true;
return 0;
@ -731,6 +746,7 @@ static void mca_be_shutdown(struct snd_pcm_substream *substream,
struct snd_soc_dai *dai)
{
struct mca_cluster *cl = mca_dai_to_cluster(dai);
struct mca_data *mca = cl->host;
cl->port_started[substream->stream] = false;
@ -741,7 +757,9 @@ static void mca_be_shutdown(struct snd_pcm_substream *substream,
*/
writel_relaxed(0, cl->base + REG_PORT_ENABLES);
writel_relaxed(0, cl->base + REG_PORT_DATA_SEL);
mutex_lock(&mca->port_mutex);
cl->port_driver = -1;
mutex_unlock(&mca->port_mutex);
}
}
@ -962,6 +980,7 @@ static int apple_mca_probe(struct platform_device *pdev)
return -ENOMEM;
mca->dev = &pdev->dev;
mca->nclusters = nclusters;
mutex_init(&mca->port_mutex);
platform_set_drvdata(pdev, mca);
clusters = mca->clusters;