Applied "ASoC: rsnd: fixup not to call clk_get/set under non-atomic" to the asoc tree

[Mark Brown <broonie@kernel.org>]

The patch

   ASoC: rsnd: fixup not to call clk_get/set under non-atomic

has been applied to the asoc tree at

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git 

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

>From 4d230d12710646788af581ba0155d83ab48b955c Mon Sep 17 00:00:00 2001
From: Jiada Wang <jiada_wang@mentor.com>
Date: Mon, 3 Sep 2018 07:08:58 +0000
Subject: [PATCH] ASoC: rsnd: fixup not to call clk_get/set under non-atomic

Clocking operations clk_get/set_rate, are non-atomic,
they shouldn't be called in soc_pcm_trigger() which is atomic.

Following issue was found due to execution of clk_get_rate() causes
sleep in soc_pcm_trigger(), which shouldn't be blocked.

We can reproduce this issue by following
	> enable CONFIG_DEBUG_ATOMIC_SLEEP=y
	> compile, and boot
	> mount -t debugfs none /sys/kernel/debug
	> while true; do cat /sys/kernel/debug/clk/clk_summary > /dev/null; done &
	> while true; do aplay xxx; done

This patch adds support to .prepare callback, and moves non-atomic
clocking operations to it. As .prepare is non-atomic, it is always
called before trigger_start/trigger_stop.

	BUG: sleeping function called from invalid context at kernel/locking/mutex.c:620
	in_atomic(): 1, irqs_disabled(): 128, pid: 2242, name: aplay
	INFO: lockdep is turned off.
	irq event stamp: 5964
	hardirqs last enabled at (5963): [<ffff200008e59e40>] mutex_lock_nested+0x6e8/0x6f0
	hardirqs last disabled at (5964): [<ffff200008e623f0>] _raw_spin_lock_irqsave+0x24/0x68
	softirqs last enabled at (5502): [<ffff200008081838>] __do_softirq+0x560/0x10c0
	softirqs last disabled at (5495): [<ffff2000080c2e78>] irq_exit+0x160/0x25c
	Preemption disabled at:[ 62.904063] [<ffff200008be4d48>] snd_pcm_stream_lock+0xb4/0xc0
	CPU: 2 PID: 2242 Comm: aplay Tainted: G B C 4.9.54+ #186
	Hardware name: Renesas Salvator-X board based on r8a7795 (DT)
	Call trace:
	[<ffff20000808fe48>] dump_backtrace+0x0/0x37c
	[<ffff2000080901d8>] show_stack+0x14/0x1c
	[<ffff2000086f4458>] dump_stack+0xfc/0x154
	[<ffff2000081134a0>] ___might_sleep+0x57c/0x58c
	[<ffff2000081136b8>] __might_sleep+0x208/0x21c
	[<ffff200008e5980c>] mutex_lock_nested+0xb4/0x6f0
	[<ffff2000087cac74>] clk_prepare_lock+0xb0/0x184
	[<ffff2000087cb094>] clk_core_get_rate+0x14/0x54
	[<ffff2000087cb0f4>] clk_get_rate+0x20/0x34
	[<ffff20000113aa00>] rsnd_adg_ssi_clk_try_start+0x158/0x4f8 [snd_soc_rcar]
	[<ffff20000113da00>] rsnd_ssi_init+0x668/0x7a0 [snd_soc_rcar]
	[<ffff200001133ff4>] rsnd_soc_dai_trigger+0x4bc/0xcf8 [snd_soc_rcar]
	[<ffff200008c1af24>] soc_pcm_trigger+0x2a4/0x2d4

Fixes: e7d850dd10f4 ("ASoC: rsnd: use mod base common method on SSI-parent")
Signed-off-by: Jiada Wang <jiada_wang@mentor.com>
Signed-off-by: Timo Wischer <twischer@de.adit-jv.com>
[Kuninori: tidyup for upstream]
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Tested-by: Hiroyuki Yokoyama <hiroyuki.yokoyama.vx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org
---
 sound/soc/sh/rcar/core.c | 11 +++++++++++
 sound/soc/sh/rcar/rsnd.h |  7 +++++++
 sound/soc/sh/rcar/ssi.c  | 16 ++++++++++------
 3 files changed, 28 insertions(+), 6 deletions(-)

diff --git a/sound/soc/sh/rcar/core.c b/sound/soc/sh/rcar/core.c
index f8425d8b44d2..b35f5509cfe2 100644
--- a/sound/soc/sh/rcar/core.c
+++ b/sound/soc/sh/rcar/core.c
@@ -958,12 +958,23 @@ static void rsnd_soc_dai_shutdown(struct snd_pcm_substream *substream,
 	rsnd_dai_stream_quit(io);
 }
 
+static int rsnd_soc_dai_prepare(struct snd_pcm_substream *substream,
+				struct snd_soc_dai *dai)
+{
+	struct rsnd_priv *priv = rsnd_dai_to_priv(dai);
+	struct rsnd_dai *rdai = rsnd_dai_to_rdai(dai);
+	struct rsnd_dai_stream *io = rsnd_rdai_to_io(rdai, substream);
+
+	return rsnd_dai_call(prepare, io, priv);
+}
+
 static const struct snd_soc_dai_ops rsnd_soc_dai_ops = {
 	.startup	= rsnd_soc_dai_startup,
 	.shutdown	= rsnd_soc_dai_shutdown,
 	.trigger	= rsnd_soc_dai_trigger,
 	.set_fmt	= rsnd_soc_dai_set_fmt,
 	.set_tdm_slot	= rsnd_soc_set_dai_tdm_slot,
+	.prepare	= rsnd_soc_dai_prepare,
 };
 
 void rsnd_parse_connect_common(struct rsnd_dai *rdai,
diff --git a/sound/soc/sh/rcar/rsnd.h b/sound/soc/sh/rcar/rsnd.h
index 96d93330b1e1..8f7a0abfa751 100644
--- a/sound/soc/sh/rcar/rsnd.h
+++ b/sound/soc/sh/rcar/rsnd.h
@@ -280,6 +280,9 @@ struct rsnd_mod_ops {
 	int (*nolock_stop)(struct rsnd_mod *mod,
 		    struct rsnd_dai_stream *io,
 		    struct rsnd_priv *priv);
+	int (*prepare)(struct rsnd_mod *mod,
+		       struct rsnd_dai_stream *io,
+		       struct rsnd_priv *priv);
 };
 
 struct rsnd_dai_stream;
@@ -309,6 +312,7 @@ struct rsnd_mod {
  * H	0: fallback
  * H	0: hw_params
  * H	0: pointer
+ * H	0: prepare
  */
 #define __rsnd_mod_shift_nolock_start	0
 #define __rsnd_mod_shift_nolock_stop	0
@@ -323,6 +327,7 @@ struct rsnd_mod {
 #define __rsnd_mod_shift_fallback	28 /* always called */
 #define __rsnd_mod_shift_hw_params	28 /* always called */
 #define __rsnd_mod_shift_pointer	28 /* always called */
+#define __rsnd_mod_shift_prepare	28 /* always called */
 
 #define __rsnd_mod_add_probe		0
 #define __rsnd_mod_add_remove		0
@@ -337,6 +342,7 @@ struct rsnd_mod {
 #define __rsnd_mod_add_fallback		0
 #define __rsnd_mod_add_hw_params	0
 #define __rsnd_mod_add_pointer		0
+#define __rsnd_mod_add_prepare		0
 
 #define __rsnd_mod_call_probe		0
 #define __rsnd_mod_call_remove		0
@@ -351,6 +357,7 @@ struct rsnd_mod {
 #define __rsnd_mod_call_pointer		0
 #define __rsnd_mod_call_nolock_start	0
 #define __rsnd_mod_call_nolock_stop	1
+#define __rsnd_mod_call_prepare		0
 
 #define rsnd_mod_to_priv(mod)	((mod)->priv)
 #define rsnd_mod_name(mod)	((mod)->ops->name)
diff --git a/sound/soc/sh/rcar/ssi.c b/sound/soc/sh/rcar/ssi.c
index 8304e4ec9242..3f880ec66459 100644
--- a/sound/soc/sh/rcar/ssi.c
+++ b/sound/soc/sh/rcar/ssi.c
@@ -283,7 +283,7 @@ static int rsnd_ssi_master_clk_start(struct rsnd_mod *mod,
 	if (rsnd_ssi_is_multi_slave(mod, io))
 		return 0;
 
-	if (ssi->usrcnt > 1) {
+	if (ssi->rate) {
 		if (ssi->rate != rate) {
 			dev_err(dev, "SSI parent/child should use same rate\n");
 			return -EINVAL;
@@ -434,7 +434,6 @@ static int rsnd_ssi_init(struct rsnd_mod *mod,
 			 struct rsnd_priv *priv)
 {
 	struct rsnd_ssi *ssi = rsnd_mod_to_ssi(mod);
-	int ret;
 
 	if (!rsnd_ssi_is_run_mods(mod, io))
 		return 0;
@@ -443,10 +442,6 @@ static int rsnd_ssi_init(struct rsnd_mod *mod,
 
 	rsnd_mod_power_on(mod);
 
-	ret = rsnd_ssi_master_clk_start(mod, io);
-	if (ret < 0)
-		return ret;
-
 	rsnd_ssi_config_init(mod, io);
 
 	rsnd_ssi_register_setup(mod);
@@ -852,6 +847,13 @@ static int rsnd_ssi_pio_pointer(struct rsnd_mod *mod,
 	return 0;
 }
 
+static int rsnd_ssi_prepare(struct rsnd_mod *mod,
+			    struct rsnd_dai_stream *io,
+			    struct rsnd_priv *priv)
+{
+	return rsnd_ssi_master_clk_start(mod, io);
+}
+
 static struct rsnd_mod_ops rsnd_ssi_pio_ops = {
 	.name	= SSI_NAME,
 	.probe	= rsnd_ssi_common_probe,
@@ -864,6 +866,7 @@ static struct rsnd_mod_ops rsnd_ssi_pio_ops = {
 	.pointer = rsnd_ssi_pio_pointer,
 	.pcm_new = rsnd_ssi_pcm_new,
 	.hw_params = rsnd_ssi_hw_params,
+	.prepare = rsnd_ssi_prepare,
 };
 
 static int rsnd_ssi_dma_probe(struct rsnd_mod *mod,
@@ -940,6 +943,7 @@ static struct rsnd_mod_ops rsnd_ssi_dma_ops = {
 	.pcm_new = rsnd_ssi_pcm_new,
 	.fallback = rsnd_ssi_fallback,
 	.hw_params = rsnd_ssi_hw_params,
+	.prepare = rsnd_ssi_prepare,
 };
 
 int rsnd_ssi_is_dma_mode(struct rsnd_mod *mod)
-- 
2.19.0.rc1