Date:   Wed, 13 Oct 2021 09:30:41 -0500
From:   Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>
To:     alsa-devel@...a-project.org
Cc:     tiwai@...e.de, broonie@...nel.org, vkoul@...nel.org,
        Sameer Pujar <spujar@...dia.com>,
        Gyeongtaek Lee <gt82.lee@...sung.com>,
        Peter Ujfalusi <peter.ujfalusi@...ux.intel.com>,
        Kuninori Morimoto <kuninori.morimoto.gx@...esas.com>,
        Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>,
        Liam Girdwood <lgirdwood@...il.com>,
        Jaroslav Kysela <perex@...ex.cz>,
        Takashi Iwai <tiwai@...e.com>,
        linux-kernel@...r.kernel.org (open list)
Subject: [RFC PATCH v3 04/13] ASoC: soc-pcm: introduce snd_soc_dpcm_fe_lock_irq/unlock_irq()

In preparation for more changes, add two new helpers to gradually
modify the DPCM locks.

Since DPCM functions are not used from interrupt handlers, we can only
use the lock_irq case.

While most of the uses of DPCM are internal to soc-pcm.c, some drivers
in soc/fsl and soc/sh do make use of DPCM-related loops that will
require protection, adding EXPORT_SYMBOL_GPL() is needed for those
drivers.

The stream argument is unused in this patch but will be enabled in
follow-up patches.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>
---
 include/sound/soc-dpcm.h |  3 +++
 sound/soc/soc-pcm.c      | 42 +++++++++++++++++++++++-----------------
 2 files changed, 27 insertions(+), 18 deletions(-)

diff --git a/include/sound/soc-dpcm.h b/include/sound/soc-dpcm.h
index 9c00118603e7..8ed40b8f3da8 100644
--- a/include/sound/soc-dpcm.h
+++ b/include/sound/soc-dpcm.h
@@ -151,4 +151,7 @@ bool dpcm_end_walk_at_be(struct snd_soc_dapm_widget *widget, enum snd_soc_dapm_d
 #define dpcm_be_dai_startup_unwind(fe, stream)	dpcm_be_dai_stop(fe, stream, 0, NULL)
 #define dpcm_be_dai_shutdown(fe, stream)	dpcm_be_dai_stop(fe, stream, 1, NULL)
 
+void snd_soc_dpcm_fe_lock_irq(struct snd_soc_pcm_runtime *fe, int stream);
+void snd_soc_dpcm_fe_unlock_irq(struct snd_soc_pcm_runtime *fe, int stream);
+
 #endif
diff --git a/sound/soc/soc-pcm.c b/sound/soc/soc-pcm.c
index 19539300d94d..52851827d53f 100644
--- a/sound/soc/soc-pcm.c
+++ b/sound/soc/soc-pcm.c
@@ -29,6 +29,18 @@
 
 #define DPCM_MAX_BE_USERS	8
 
+void snd_soc_dpcm_fe_lock_irq(struct snd_soc_pcm_runtime *fe, int stream)
+{
+	spin_lock_irq(&fe->card->dpcm_lock);
+}
+EXPORT_SYMBOL_GPL(snd_soc_dpcm_fe_lock_irq);
+
+void snd_soc_dpcm_fe_unlock_irq(struct snd_soc_pcm_runtime *fe, int stream)
+{
+	spin_unlock_irq(&fe->card->dpcm_lock);
+}
+EXPORT_SYMBOL_GPL(snd_soc_dpcm_fe_unlock_irq);
+
 /* can this BE stop and free */
 static int snd_soc_dpcm_can_be_free_stop(struct snd_soc_pcm_runtime *fe,
 					 struct snd_soc_pcm_runtime *be, int stream);
@@ -85,7 +97,6 @@ static ssize_t dpcm_show_state(struct snd_soc_pcm_runtime *fe,
 	struct snd_pcm_hw_params *params = &fe->dpcm[stream].hw_params;
 	struct snd_soc_dpcm *dpcm;
 	ssize_t offset = 0;
-	unsigned long flags;
 
 	/* FE state */
 	offset += scnprintf(buf + offset, size - offset,
@@ -113,7 +124,7 @@ static ssize_t dpcm_show_state(struct snd_soc_pcm_runtime *fe,
 		goto out;
 	}
 
-	spin_lock_irqsave(&fe->card->dpcm_lock, flags);
+	snd_soc_dpcm_fe_lock_irq(fe, stream);
 	for_each_dpcm_be(fe, stream, dpcm) {
 		struct snd_soc_pcm_runtime *be = dpcm->be;
 		params = &dpcm->hw_params;
@@ -134,7 +145,7 @@ static ssize_t dpcm_show_state(struct snd_soc_pcm_runtime *fe,
 					   params_channels(params),
 					   params_rate(params));
 	}
-	spin_unlock_irqrestore(&fe->card->dpcm_lock, flags);
+	snd_soc_dpcm_fe_unlock_irq(fe, stream);
 out:
 	return offset;
 }
@@ -1141,7 +1152,6 @@ static int dpcm_be_connect(struct snd_soc_pcm_runtime *fe,
 		struct snd_soc_pcm_runtime *be, int stream)
 {
 	struct snd_soc_dpcm *dpcm;
-	unsigned long flags;
 
 	/* only add new dpcms */
 	for_each_dpcm_be(fe, stream, dpcm) {
@@ -1157,10 +1167,10 @@ static int dpcm_be_connect(struct snd_soc_pcm_runtime *fe,
 	dpcm->fe = fe;
 	be->dpcm[stream].runtime = fe->dpcm[stream].runtime;
 	dpcm->state = SND_SOC_DPCM_LINK_STATE_NEW;
-	spin_lock_irqsave(&fe->card->dpcm_lock, flags);
+	snd_soc_dpcm_fe_lock_irq(fe, stream);
 	list_add(&dpcm->list_be, &fe->dpcm[stream].be_clients);
 	list_add(&dpcm->list_fe, &be->dpcm[stream].fe_clients);
-	spin_unlock_irqrestore(&fe->card->dpcm_lock, flags);
+	snd_soc_dpcm_fe_unlock_irq(fe, stream);
 
 	dev_dbg(fe->dev, "connected new DPCM %s path %s %s %s\n",
 			stream ? "capture" : "playback",  fe->dai_link->name,
@@ -1203,7 +1213,6 @@ static void dpcm_be_reparent(struct snd_soc_pcm_runtime *fe,
 void dpcm_be_disconnect(struct snd_soc_pcm_runtime *fe, int stream)
 {
 	struct snd_soc_dpcm *dpcm, *d;
-	unsigned long flags;
 
 	for_each_dpcm_be_safe(fe, stream, dpcm, d) {
 		dev_dbg(fe->dev, "ASoC: BE %s disconnect check for %s\n",
@@ -1222,10 +1231,10 @@ void dpcm_be_disconnect(struct snd_soc_pcm_runtime *fe, int stream)
 
 		dpcm_remove_debugfs_state(dpcm);
 
-		spin_lock_irqsave(&fe->card->dpcm_lock, flags);
+		snd_soc_dpcm_fe_lock_irq(fe, stream);
 		list_del(&dpcm->list_be);
 		list_del(&dpcm->list_fe);
-		spin_unlock_irqrestore(&fe->card->dpcm_lock, flags);
+		snd_soc_dpcm_fe_unlock_irq(fe, stream);
 		kfree(dpcm);
 	}
 }
@@ -1451,12 +1460,11 @@ int dpcm_process_paths(struct snd_soc_pcm_runtime *fe,
 void dpcm_clear_pending_state(struct snd_soc_pcm_runtime *fe, int stream)
 {
 	struct snd_soc_dpcm *dpcm;
-	unsigned long flags;
 
-	spin_lock_irqsave(&fe->card->dpcm_lock, flags);
+	snd_soc_dpcm_fe_lock_irq(fe, stream);
 	for_each_dpcm_be(fe, stream, dpcm)
 		dpcm_set_be_update_state(dpcm->be, stream, SND_SOC_DPCM_UPDATE_NO);
-	spin_unlock_irqrestore(&fe->card->dpcm_lock, flags);
+	snd_soc_dpcm_fe_unlock_irq(fe, stream);
 }
 
 void dpcm_be_dai_stop(struct snd_soc_pcm_runtime *fe, int stream,
@@ -2374,7 +2382,6 @@ static int dpcm_run_update_startup(struct snd_soc_pcm_runtime *fe, int stream)
 	struct snd_soc_dpcm *dpcm;
 	enum snd_soc_dpcm_trigger trigger = fe->dai_link->trigger[stream];
 	int ret = 0;
-	unsigned long flags;
 
 	dev_dbg(fe->dev, "ASoC: runtime %s open on FE %s\n",
 			stream ? "capture" : "playback", fe->dai_link->name);
@@ -2443,7 +2450,7 @@ static int dpcm_run_update_startup(struct snd_soc_pcm_runtime *fe, int stream)
 	dpcm_be_dai_shutdown(fe, stream);
 disconnect:
 	/* disconnect any pending BEs */
-	spin_lock_irqsave(&fe->card->dpcm_lock, flags);
+	snd_soc_dpcm_fe_lock_irq(fe, stream);
 	for_each_dpcm_be(fe, stream, dpcm) {
 		struct snd_soc_pcm_runtime *be = dpcm->be;
 
@@ -2455,7 +2462,7 @@ static int dpcm_run_update_startup(struct snd_soc_pcm_runtime *fe, int stream)
 			be->dpcm[stream].state == SND_SOC_DPCM_STATE_NEW)
 				dpcm->state = SND_SOC_DPCM_LINK_STATE_FREE;
 	}
-	spin_unlock_irqrestore(&fe->card->dpcm_lock, flags);
+	snd_soc_dpcm_fe_unlock_irq(fe, stream);
 
 	if (ret < 0)
 		dev_err(fe->dev, "ASoC: %s() failed (%d)\n", __func__, ret);
@@ -2855,10 +2862,9 @@ static int snd_soc_dpcm_check_state(struct snd_soc_pcm_runtime *fe,
 	struct snd_soc_dpcm *dpcm;
 	int state;
 	int ret = 1;
-	unsigned long flags;
 	int i;
 
-	spin_lock_irqsave(&fe->card->dpcm_lock, flags);
+	snd_soc_dpcm_fe_lock_irq(fe, stream);
 	for_each_dpcm_fe(be, stream, dpcm) {
 
 		if (dpcm->fe == fe)
@@ -2872,7 +2878,7 @@ static int snd_soc_dpcm_check_state(struct snd_soc_pcm_runtime *fe,
 			}
 		}
 	}
-	spin_unlock_irqrestore(&fe->card->dpcm_lock, flags);
+	snd_soc_dpcm_fe_unlock_irq(fe, stream);
 
 	/* it's safe to do this BE DAI */
 	return ret;
-- 
2.25.1

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