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

commit 4d230d1 upstream.

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+ raspberrypi#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: e7d850d ("ASoC: rsnd: use mod base common method on SSI-parent")
Signed-off-by: Jiada Wang <[email protected]>
Signed-off-by: Timo Wischer <[email protected]>
[Kuninori: tidyup for upstream]
Signed-off-by: Kuninori Morimoto <[email protected]>
Tested-by: Hiroyuki Yokoyama <[email protected]>
Signed-off-by: Mark Brown <[email protected]>
Cc: [email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

sound/soc/sh/rcar/core.c

@@ -925,12 +925,23 @@ static void rsnd_soc_dai_shutdown(struct snd_pcm_substream *substream,
 	rsnd_dai_call(nolock_stop, io, priv);
 }
 
+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,

sound/soc/sh/rcar/rsnd.h

@@ -283,6 +283,9 @@ 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;
@@ -312,6 +315,7 @@ 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
@@ -326,6 +330,7 @@ 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
@@ -340,6 +345,7 @@ 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
@@ -354,6 +360,7 @@ 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_id(mod) ((mod) ? (mod)->id : -1)

sound/soc/sh/rcar/ssi.c

@@ -280,7 +280,7 @@ 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;
@@ -482,7 +482,6 @@ 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;
@@ -493,10 +492,6 @@ 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);
@@ -847,6 +842,13 @@ static int rsnd_ssi_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,
@@ -859,6 +861,7 @@ static struct rsnd_mod_ops rsnd_ssi_pio_ops = {
 	.pointer= rsnd_ssi_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,
@@ -935,6 +938,7 @@ 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)