[PATCH 07/10] ASoC: rsnd: protect mod->status

[Kuninori Morimoto]

From: Kuninori Morimoto <kuninori.morimoto.gx at renesas.com>

Renesas Sound uses many modules (SSI/SSIU/SRC/CTU/MIX/DVC/DMA),
and supports complex connections/path.
Thus each modules needs to save its status to correctly control it.
This status is updated when by .trigger, and .hw_params/.hw_free.

Renesas Sound is protecting modules by using lock when .trigger,
but it was not enough to protecting each modules "status" if it was
used from many paths.

1) .hw_params/.hw_free update status
2) another doesn't update status, but overwrites by same value

This patch do
1) protects .hw_params/.hw_free by lock
2) do nothing if no status update

Without this patch, protected mod->status (= .trigger) might be
overwrote by non protected mod->status (= .hw_params / .hw_free),
and in such case, CTU/MIX/DVC/SSIU/SSI which are used from
many paths might get damage.

If above issue happens, Renesas Sound will be hung (= silence)
and never be recoverd.
I could reproduce this issue by continue playing very short sound
with loop very long term (3-4 hours) through 2 inputs (= MIXer).

For updating rsnd_status_update(), this patch removes rsnd_dai_call()
debug message. Because we already have debugfs support, and is not
good match to new code.

Reported-by: Linh Phung T. Y <linh.phung.jy at renesas.com>
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx at renesas.com>
---
 sound/soc/sh/rcar/core.c | 50 ++++++++++++++++++++++++----------------
 sound/soc/sh/rcar/rsnd.h | 12 +++++-----
 2 files changed, 36 insertions(+), 26 deletions(-)

diff --git a/sound/soc/sh/rcar/core.c b/sound/soc/sh/rcar/core.c
index f37952e40879..c5b67008a15f 100644
--- a/sound/soc/sh/rcar/core.c
+++ b/sound/soc/sh/rcar/core.c
@@ -90,14 +90,6 @@
  *
  */
 
-/*
- * you can enable below define if you don't need
- * DAI status debug message when debugging
- * see rsnd_dbg_dai_call()
- *
- * #define RSND_DEBUG_NO_DAI_CALL 1
- */
-
 #include <linux/pm_runtime.h>
 #include "rsnd.h"
 
@@ -534,14 +526,20 @@ static enum rsnd_mod_type rsnd_mod_sequence[][RSND_MOD_MAX] = {
 	},
 };
 
-static int rsnd_status_update(u32 *status,
+static int rsnd_status_update(struct rsnd_dai_stream *io,
+			      struct rsnd_mod *mod, enum rsnd_mod_type type,
 			      int shift, int add, int timing)
 {
+	u32 *status	= mod->ops->get_status(mod, io, type);
 	u32 mask	= 0xF << shift;
 	u8 val		= (*status >> shift) & 0xF;
 	u8 next_val	= (val + add) & 0xF;
 	int func_call	= (val == timing);
 
+	/* no status update */
+	if (add == 0 || shift == 28)
+		return 1;
+
 	if (next_val == 0xF) /* underflow case */
 		func_call = -1;
 	else
@@ -559,14 +557,10 @@ static int rsnd_status_update(u32 *status,
 	enum rsnd_mod_type *types = rsnd_mod_sequence[is_play];		\
 	for_each_rsnd_mod_arrays(i, mod, io, types, RSND_MOD_MAX) {	\
 		int tmp = 0;						\
-		u32 *status = mod->ops->get_status(mod, io, types[i]);	\
-		int func_call = rsnd_status_update(status,		\
+		int func_call = rsnd_status_update(io, mod, types[i],	\
 						__rsnd_mod_shift_##fn,	\
 						__rsnd_mod_add_##fn,	\
 						__rsnd_mod_call_##fn);	\
-		rsnd_dbg_dai_call(dev, "%s\t0x%08x %s\n",		\
-			rsnd_mod_name(mod), *status,	\
-			(func_call && (mod)->ops->fn) ? #fn : "");	\
 		if (func_call > 0 && (mod)->ops->fn)			\
 			tmp = (mod)->ops->fn(mod, io, param);		\
 		if (unlikely(func_call < 0) ||				\
@@ -1410,6 +1404,26 @@ static int rsnd_dai_probe(struct rsnd_priv *priv)
 /*
  *		pcm ops
  */
+static int rsnd_hw_update(struct snd_pcm_substream *substream,
+			  struct snd_pcm_hw_params *hw_params)
+{
+	struct snd_soc_dai *dai = rsnd_substream_to_dai(substream);
+	struct rsnd_dai *rdai = rsnd_dai_to_rdai(dai);
+	struct rsnd_dai_stream *io = rsnd_rdai_to_io(rdai, substream);
+	struct rsnd_priv *priv = rsnd_io_to_priv(io);
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(&priv->lock, flags);
+	if (hw_params)
+		ret = rsnd_dai_call(hw_params, io, substream, hw_params);
+	else
+		ret = rsnd_dai_call(hw_free, io, substream);
+	spin_unlock_irqrestore(&priv->lock, flags);
+
+	return ret;
+}
+
 static int rsnd_hw_params(struct snd_soc_component *component,
 			  struct snd_pcm_substream *substream,
 			  struct snd_pcm_hw_params *hw_params)
@@ -1517,17 +1531,13 @@ static int rsnd_hw_params(struct snd_soc_component *component,
 		}
 	}
 
-	return rsnd_dai_call(hw_params, io, substream, hw_params);
+	return rsnd_hw_update(substream, hw_params);
 }
 
 static int rsnd_hw_free(struct snd_soc_component *component,
 			struct snd_pcm_substream *substream)
 {
-	struct snd_soc_dai *dai = rsnd_substream_to_dai(substream);
-	struct rsnd_dai *rdai = rsnd_dai_to_rdai(dai);
-	struct rsnd_dai_stream *io = rsnd_rdai_to_io(rdai, substream);
-
-	return rsnd_dai_call(hw_free, io, substream);
+	return rsnd_hw_update(substream, NULL);
 }
 
 static snd_pcm_uframes_t rsnd_pointer(struct snd_soc_component *component,
diff --git a/sound/soc/sh/rcar/rsnd.h b/sound/soc/sh/rcar/rsnd.h
index 4ba76b782d2e..b76dfa93d362 100644
--- a/sound/soc/sh/rcar/rsnd.h
+++ b/sound/soc/sh/rcar/rsnd.h
@@ -397,12 +397,12 @@ struct rsnd_mod {
 #define __rsnd_mod_add_remove		0
 #define __rsnd_mod_add_prepare		0
 #define __rsnd_mod_add_cleanup		0
-#define __rsnd_mod_add_init		 1
-#define __rsnd_mod_add_quit		-1
-#define __rsnd_mod_add_start		 1
-#define __rsnd_mod_add_stop		-1
-#define __rsnd_mod_add_hw_params	1
-#define __rsnd_mod_add_hw_free		-1
+#define __rsnd_mod_add_init		 1 /* needs protect */
+#define __rsnd_mod_add_quit		-1 /* needs protect */
+#define __rsnd_mod_add_start		 1 /* needs protect */
+#define __rsnd_mod_add_stop		-1 /* needs protect */
+#define __rsnd_mod_add_hw_params	 1 /* needs protect */
+#define __rsnd_mod_add_hw_free		-1 /* needs protect */
 #define __rsnd_mod_add_irq		0
 #define __rsnd_mod_add_pcm_new		0
 #define __rsnd_mod_add_fallback		0
-- 
2.25.1