ASoC: soc-link: introduce exit() callback

Some machine drivers allocate or request resources with
snd_soc_link_init() phase of the card probe. These resources need to
be properly released when removing a card, and this patch suggests a
dual exit() callback.

The exit() is invoked in soc_remove_pcm_runtime(), which is not
completely symmetric with the init() invoked in soc_init_pcm_runtime().

Alternate solutions were considered, e.g. adding a .remove() callback
for the platform driver, but that's not symmetrical at all and would
be difficult to handle if there are more than one dailink implementing
an .init(). We looked also into using .remove_dai_link() callback, but
that would also be imbalanced.

Note that because of the error handling in snd_soc_bind_card(), which
jumps to probe_end, there is no way to guarantee the exit() is invoked
with resources allocated in the init(). Prior to releasing those
resources, implementations of the exit() callback shall check the
resources are valid.

Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Reviewed-by: Curtis Malainey <curtis@malainey.com>
Link: https://lore.kernel.org/r/20200622154241.29053-2-pierre-louis.bossart@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/include/sound/soc-link.h b/include/sound/soc-link.h
index 3dd6e33e94ecd350b61b5dbc65eeb18711057bf3..337ac566675789c07fb941a9cdc158060e6f6791 100644 (file)
--- a/include/sound/soc-link.h
+++ b/include/sound/soc-link.h
@@ -9,6 +9,7 @@
 #define __SOC_LINK_H
 
 int snd_soc_link_init(struct snd_soc_pcm_runtime *rtd);
+void snd_soc_link_exit(struct snd_soc_pcm_runtime *rtd);
 int snd_soc_link_be_hw_params_fixup(struct snd_soc_pcm_runtime *rtd,
                                    struct snd_pcm_hw_params *params);
 

diff --git a/include/sound/soc.h b/include/sound/soc.h
index 2756f9bcac3e487bd9994e9b9bf88ae169c4cfe6..33aceadebd0314a209ba2d020155402621fb5dfe 100644 (file)
--- a/include/sound/soc.h
+++ b/include/sound/soc.h
@@ -799,6 +799,9 @@ struct snd_soc_dai_link {
        /* codec/machine specific init - e.g. add machine controls */
        int (*init)(struct snd_soc_pcm_runtime *rtd);
 
+       /* codec/machine specific exit - dual of init() */
+       void (*exit)(struct snd_soc_pcm_runtime *rtd);
+
        /* optional hw_params re-writing for BE and FE sync */
        int (*be_hw_params_fixup)(struct snd_soc_pcm_runtime *rtd,
                        struct snd_pcm_hw_params *params);

diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c
index 62c0c9482018dbda08fa2989b8a33e2fd22091a4..adedadcb0efb4dea4acfd5bf849a6c30d0dd7791 100644 (file)
--- a/sound/soc/soc-core.c
+++ b/sound/soc/soc-core.c
@@ -945,6 +945,9 @@ void snd_soc_remove_pcm_runtime(struct snd_soc_card *card,
 {
        lockdep_assert_held(&client_mutex);
 
+       /* release machine specific resources */
+       snd_soc_link_exit(rtd);
+
        /*
         * Notify the machine driver for extra destruction
         */

diff --git a/sound/soc/soc-link.c b/sound/soc/soc-link.c
index f849278beba0899f603df67ba9aa12e140851c08..1c3bf2118718e89baa5bf0ecc96303be1d0a2379 100644 (file)
--- a/sound/soc/soc-link.c
+++ b/sound/soc/soc-link.c
@@ -40,6 +40,12 @@ int snd_soc_link_init(struct snd_soc_pcm_runtime *rtd)
        return soc_link_ret(rtd, ret);
 }
 
+void snd_soc_link_exit(struct snd_soc_pcm_runtime *rtd)
+{
+       if (rtd->dai_link->exit)
+               rtd->dai_link->exit(rtd);
+}
+
 int snd_soc_link_be_hw_params_fixup(struct snd_soc_pcm_runtime *rtd,
                                    struct snd_pcm_hw_params *params)
 {