linux-kernel - [PATCH v7 3/4] ASoC: fsl_ssi: Add dual fifo mode support

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <6ee839eec507d6b928beb7c04765acfa9cca8d7a.1384352281.git.b42378@freescale.com>
Date:	Wed, 13 Nov 2013 22:55:26 +0800
From:	Nicolin Chen <b42378@...escale.com>
To:	<vinod.koul@...el.com>, <dan.j.williams@...el.com>,
	<s.hauer@...gutronix.de>, <timur@...i.org>, <shawn.guo@...aro.org>,
	<broonie@...nel.org>
CC:	<linux-arm-kernel@...ts.infradead.org>,
	<devicetree@...r.kernel.org>, <linux-doc@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>, <dmaengine@...r.kernel.org>,
	<linuxppc-dev@...ts.ozlabs.org>, <alsa-devel@...a-project.org>,
	<rob.herring@...xeda.com>, <mark.rutland@....com>,
	<swarren@...dotorg.org>, <pawel.moll@....com>,
	<ijc+devicetree@...lion.org.uk>
Subject: [PATCH v7 3/4] ASoC: fsl_ssi: Add dual fifo mode support

By enabling dual fifo mode, it would allow SSI enter a better performance
to transimit/receive data without occasional hardware underrun/overrun.

Signed-off-by: Nicolin Chen <b42378@...escale.com>
Acked-by: Timur Tabi <timur@...i.org>
Acked-by: Mark Brown <broonie@...aro.org>
---
 sound/soc/fsl/fsl_ssi.c | 27 ++++++++++++++++++++++++++-
 1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/sound/soc/fsl/fsl_ssi.c b/sound/soc/fsl/fsl_ssi.c
index 35e2773..f43be6d 100644
--- a/sound/soc/fsl/fsl_ssi.c
+++ b/sound/soc/fsl/fsl_ssi.c
@@ -143,6 +143,7 @@ struct fsl_ssi_private {
 	bool ssi_on_imx;
 	bool imx_ac97;
 	bool use_dma;
+	bool use_dual_fifo;
 	struct clk *clk;
 	struct snd_dmaengine_dai_dma_data dma_params_tx;
 	struct snd_dmaengine_dai_dma_data dma_params_rx;
@@ -413,6 +414,12 @@ static int fsl_ssi_setup(struct fsl_ssi_private *ssi_private)
 		write_ssi(CCSR_SSI_SOR_WAIT(3), &ssi->sor);
 	}
 
+	if (ssi_private->use_dual_fifo) {
+		write_ssi_mask(&ssi->srcr, 0, CCSR_SSI_SRCR_RFEN1);
+		write_ssi_mask(&ssi->stcr, 0, CCSR_SSI_STCR_TFEN1);
+		write_ssi_mask(&ssi->scr, 0, CCSR_SSI_SCR_TCH_EN);
+	}
+
 	return 0;
 }
 
@@ -480,6 +487,15 @@ static int fsl_ssi_startup(struct snd_pcm_substream *substream,
 		ssi_private->second_stream = substream;
 	}
 
+	/* When using dual fifo mode, it is safer to ensure an even period
+	 * size. If appearing to an odd number while DMA always starts its
+	 * task from fifo0, fifo1 would be neglected at the end of each
+	 * period. But SSI would still access fifo1 with an invalid data.
+	 */
+	if (ssi_private->use_dual_fifo)
+		snd_pcm_hw_constraint_step(substream->runtime, 0,
+				SNDRV_PCM_HW_PARAM_PERIOD_SIZE, 2);
+
 	return 0;
 }
 
@@ -947,7 +963,7 @@ static int fsl_ssi_probe(struct platform_device *pdev)
 		ssi_private->fifo_depth = 8;
 
 	if (of_device_is_compatible(pdev->dev.of_node, "fsl,imx21-ssi")) {
-		u32 dma_events[2];
+		u32 dma_events[2], dmas[4];
 		ssi_private->ssi_on_imx = true;
 
 		ssi_private->clk = devm_clk_get(&pdev->dev, NULL);
@@ -1001,6 +1017,15 @@ static int fsl_ssi_probe(struct platform_device *pdev)
 			dma_events[0], shared ? IMX_DMATYPE_SSI_SP : IMX_DMATYPE_SSI);
 		imx_pcm_dma_params_init_data(&ssi_private->filter_data_rx,
 			dma_events[1], shared ? IMX_DMATYPE_SSI_SP : IMX_DMATYPE_SSI);
+		if (!of_property_read_u32_array(pdev->dev.of_node, "dmas", dmas, 4)
+				&& dmas[2] == IMX_DMATYPE_SSI_DUAL) {
+			ssi_private->use_dual_fifo = true;
+			/* When using dual fifo mode, we need to keep watermark
+			 * as even numbers due to dma script limitation.
+			 */
+			ssi_private->dma_params_tx.maxburst &= ~0x1;
+			ssi_private->dma_params_rx.maxburst &= ~0x1;
+		}
 	} else if (ssi_private->use_dma) {
 		/* The 'name' should not have any slashes in it. */
 		ret = devm_request_irq(&pdev->dev, ssi_private->irq,
-- 
1.8.4


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/