[PATCH 20/31] ASoC: sh: rz-ssi: Add suspend to RAM support

[Claudiu <claudiu.beznea@xxxxxxxxx>]

From: Claudiu Beznea <claudiu.beznea.uj@xxxxxxxxxxxxxx>

The SSIF-2 IP is available on the Renesas RZ/G3S SoC. The Renesas RZ/G3S
SoC supports a power-saving mode where power to most of the SoC
components is turned off. Add suspend/resume support to the SSIF-2 driver
to support this power-saving mode.

On SNDRV_PCM_TRIGGER_SUSPEND trigger the SSI is stopped (the stream
user pointer is left untouched to avoid breaking user space and the dma
buffer pointer is set to zero), on SNDRV_PCM_TRIGGER_RESUME software reset
is issued for the SSIF-2 IP and the clocks are re-configured.

Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@xxxxxxxxxxxxxx>
---
 sound/soc/renesas/rz-ssi.c | 46 ++++++++++++++++++++++++++++++++++++--
 1 file changed, 44 insertions(+), 2 deletions(-)

diff --git a/sound/soc/renesas/rz-ssi.c b/sound/soc/renesas/rz-ssi.c
index f767a667c2bf..4fbcc8f11d54 100644
--- a/sound/soc/renesas/rz-ssi.c
+++ b/sound/soc/renesas/rz-ssi.c
@@ -782,6 +782,32 @@ static int rz_ssi_dma_request(struct rz_ssi_priv *ssi, struct device *dev)
 	return -ENODEV;
 }
 
+static int rz_ssi_trigger_resume(struct rz_ssi_priv *ssi)
+{
+	int ret;
+
+	if (rz_ssi_is_stream_running(&ssi->playback) ||
+	    rz_ssi_is_stream_running(&ssi->capture))
+		return 0;
+
+	ret = rz_ssi_swreset(ssi);
+	if (ret)
+		return ret;
+
+	return rz_ssi_clk_setup(ssi, ssi->hw_params_cache.rate,
+				ssi->hw_params_cache.channels);
+}
+
+static void rz_ssi_streams_suspend(struct rz_ssi_priv *ssi)
+{
+	if (rz_ssi_is_stream_running(&ssi->playback) ||
+	    rz_ssi_is_stream_running(&ssi->capture))
+		return;
+
+	ssi->playback.dma_buffer_pos = 0;
+	ssi->capture.dma_buffer_pos = 0;
+}
+
 static int rz_ssi_dai_trigger(struct snd_pcm_substream *substream, int cmd,
 			      struct snd_soc_dai *dai)
 {
@@ -790,8 +816,16 @@ static int rz_ssi_dai_trigger(struct snd_pcm_substream *substream, int cmd,
 	int ret = 0, i, num_transfer = 1;
 
 	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_RESUME:
+		ret = rz_ssi_trigger_resume(ssi);
+		if (ret)
+			return ret;
+
+		fallthrough;
+
 	case SNDRV_PCM_TRIGGER_START:
-		rz_ssi_stream_init(strm, substream);
+		if (cmd == SNDRV_PCM_TRIGGER_START)
+			rz_ssi_stream_init(strm, substream);
 
 		if (ssi->dma_rt) {
 			bool is_playback;
@@ -819,6 +853,12 @@ static int rz_ssi_dai_trigger(struct snd_pcm_substream *substream, int cmd,
 
 		ret = rz_ssi_start(ssi, strm);
 		break;
+
+	case SNDRV_PCM_TRIGGER_SUSPEND:
+		rz_ssi_stop(ssi, strm);
+		rz_ssi_streams_suspend(ssi);
+		break;
+
 	case SNDRV_PCM_TRIGGER_STOP:
 		rz_ssi_stop(ssi, strm);
 		rz_ssi_stream_quit(ssi, strm);
@@ -958,7 +998,8 @@ static const struct snd_soc_dai_ops rz_ssi_dai_ops = {
 static const struct snd_pcm_hardware rz_ssi_pcm_hardware = {
 	.info			= SNDRV_PCM_INFO_INTERLEAVED	|
 				  SNDRV_PCM_INFO_MMAP		|
-				  SNDRV_PCM_INFO_MMAP_VALID,
+				  SNDRV_PCM_INFO_MMAP_VALID	|
+				  SNDRV_PCM_INFO_RESUME,
 	.buffer_bytes_max	= PREALLOC_BUFFER,
 	.period_bytes_min	= 32,
 	.period_bytes_max	= 8192,
@@ -1201,6 +1242,7 @@ static int rz_ssi_runtime_resume(struct device *dev)
 
 static const struct dev_pm_ops rz_ssi_pm_ops = {
 	RUNTIME_PM_OPS(rz_ssi_runtime_suspend, rz_ssi_runtime_resume, NULL)
+	SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, pm_runtime_force_resume)
 };
 
 static struct platform_driver rz_ssi_driver = {
-- 
2.39.2