linux-kernel - [PATCH] ASoC: meson: axg-fifo: add NO_PERIOD

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Message-Id: <20210407145914.311479-1-jbrunet@baylibre.com>
Date:   Wed,  7 Apr 2021 16:59:14 +0200
From:   Jerome Brunet <jbrunet@...libre.com>
To:     Mark Brown <broonie@...nel.org>,
        Liam Girdwood <lgirdwood@...il.com>
Cc:     Jerome Brunet <jbrunet@...libre.com>, alsa-devel@...a-project.org,
        linux-kernel@...r.kernel.org, linux-amlogic@...ts.infradead.org,
        Kevin Hilman <khilman@...libre.com>
Subject: [PATCH] ASoC: meson: axg-fifo: add NO_PERIOD_WAKEUP support

On the AXG family, the fifo irq is not necessary for the HW to operate.
It is just used to notify that a period has elapsed. If userpace does not
care for these wakeups (such as pipewire), we are just wasting CPU cycles.

Add support for NO_PERIOD_WAKEUP and disable irq when they are no needed.

Signed-off-by: Jerome Brunet <jbrunet@...libre.com>
---
 sound/soc/meson/axg-fifo.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/sound/soc/meson/axg-fifo.c b/sound/soc/meson/axg-fifo.c
index b2e867113226..b9af2d513e09 100644
--- a/sound/soc/meson/axg-fifo.c
+++ b/sound/soc/meson/axg-fifo.c
@@ -27,8 +27,8 @@ static struct snd_pcm_hardware axg_fifo_hw = {
 		 SNDRV_PCM_INFO_MMAP |
 		 SNDRV_PCM_INFO_MMAP_VALID |
 		 SNDRV_PCM_INFO_BLOCK_TRANSFER |
-		 SNDRV_PCM_INFO_PAUSE),
-
+		 SNDRV_PCM_INFO_PAUSE |
+		 SNDRV_PCM_INFO_NO_PERIOD_WAKEUP),
 	.formats = AXG_FIFO_FORMATS,
 	.rate_min = 5512,
 	.rate_max = 192000,
@@ -113,7 +113,7 @@ int axg_fifo_pcm_hw_params(struct snd_soc_component *component,
 {
 	struct snd_pcm_runtime *runtime = ss->runtime;
 	struct axg_fifo *fifo = axg_fifo_data(ss);
-	unsigned int burst_num, period, threshold;
+	unsigned int burst_num, period, threshold, irq_en;
 	dma_addr_t end_ptr;
 
 	period = params_period_bytes(params);
@@ -142,10 +142,11 @@ int axg_fifo_pcm_hw_params(struct snd_soc_component *component,
 	regmap_field_write(fifo->field_threshold,
 			   threshold ? threshold - 1 : 0);
 
-	/* Enable block count irq */
+	/* Enable irq if necessary  */
+	irq_en = runtime->no_period_wakeup ? 0 : FIFO_INT_COUNT_REPEAT;
 	regmap_update_bits(fifo->map, FIFO_CTRL0,
 			   CTRL0_INT_EN(FIFO_INT_COUNT_REPEAT),
-			   CTRL0_INT_EN(FIFO_INT_COUNT_REPEAT));
+			   CTRL0_INT_EN(irq_en));
 
 	return 0;
 }
-- 
2.30.2