The patch
ASoC: fsl_ssi: serialize AC'97 register access operations
has been applied to the asoc tree at
https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git
All being well this means that it will be integrated into the linux-next tree (usually sometime in the next 24 hours) and sent to Linus during the next merge window (or sooner if it is a bug fix), however if problems are discovered then the patch may be dropped or reverted.
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Thanks, Mark
From b880b8056b31288323745a13930bc45cf4c86e9d Mon Sep 17 00:00:00 2001
From: "Maciej S. Szmigiero" mail@maciej.szmigiero.name Date: Mon, 20 Nov 2017 23:16:07 +0100 Subject: [PATCH] ASoC: fsl_ssi: serialize AC'97 register access operations
AC'97 register access operations (both read and write) on SSI use a one, shared set of SSI registers for AC'97 register address and data. This means that only one such access is possible at a time and so all these operations need to be serialized.
Since an AC'97 register access operation in this driver takes 100us+ let's use a mutex for this.
Use this opportunity to also change a default value returned from AC'97 register read function from -1 to 0, since that's what AC'97 specs require to be returned when unknown / undefined registers are read.
Signed-off-by: Maciej S. Szmigiero mail@maciej.szmigiero.name Signed-off-by: Mark Brown broonie@kernel.org --- sound/soc/fsl/fsl_ssi.c | 26 ++++++++++++++++++++++---- 1 file changed, 22 insertions(+), 4 deletions(-)
diff --git a/sound/soc/fsl/fsl_ssi.c b/sound/soc/fsl/fsl_ssi.c index c3a83ed0297e..424bafaf51ef 100644 --- a/sound/soc/fsl/fsl_ssi.c +++ b/sound/soc/fsl/fsl_ssi.c @@ -38,6 +38,7 @@ #include <linux/ctype.h> #include <linux/device.h> #include <linux/delay.h> +#include <linux/mutex.h> #include <linux/slab.h> #include <linux/spinlock.h> #include <linux/of.h> @@ -265,6 +266,8 @@ struct fsl_ssi_private {
u32 fifo_watermark; u32 dma_maxburst; + + struct mutex ac97_reg_lock; };
/* @@ -1260,11 +1263,13 @@ static void fsl_ssi_ac97_write(struct snd_ac97 *ac97, unsigned short reg, if (reg > 0x7f) return;
+ mutex_lock(&fsl_ac97_data->ac97_reg_lock); + ret = clk_prepare_enable(fsl_ac97_data->clk); if (ret) { pr_err("ac97 write clk_prepare_enable failed: %d\n", ret); - return; + goto ret_unlock; }
lreg = reg << 12; @@ -1278,6 +1283,9 @@ static void fsl_ssi_ac97_write(struct snd_ac97 *ac97, unsigned short reg, udelay(100);
clk_disable_unprepare(fsl_ac97_data->clk); + +ret_unlock: + mutex_unlock(&fsl_ac97_data->ac97_reg_lock); }
static unsigned short fsl_ssi_ac97_read(struct snd_ac97 *ac97, @@ -1285,16 +1293,18 @@ static unsigned short fsl_ssi_ac97_read(struct snd_ac97 *ac97, { struct regmap *regs = fsl_ac97_data->regs;
- unsigned short val = -1; + unsigned short val = 0; u32 reg_val; unsigned int lreg; int ret;
+ mutex_lock(&fsl_ac97_data->ac97_reg_lock); + ret = clk_prepare_enable(fsl_ac97_data->clk); if (ret) { pr_err("ac97 read clk_prepare_enable failed: %d\n", ret); - return -1; + goto ret_unlock; }
lreg = (reg & 0x7f) << 12; @@ -1309,6 +1319,8 @@ static unsigned short fsl_ssi_ac97_read(struct snd_ac97 *ac97,
clk_disable_unprepare(fsl_ac97_data->clk);
+ret_unlock: + mutex_unlock(&fsl_ac97_data->ac97_reg_lock); return val; }
@@ -1569,6 +1581,7 @@ static int fsl_ssi_probe(struct platform_device *pdev) }
if (fsl_ssi_is_ac97(ssi_private)) { + mutex_init(&ssi_private->ac97_reg_lock); ret = snd_soc_set_ac97_ops_of_reset(&fsl_ssi_ac97_ops, pdev); if (ret) { dev_err(&pdev->dev, "could not set AC'97 ops\n"); @@ -1663,6 +1676,9 @@ static int fsl_ssi_probe(struct platform_device *pdev) snd_soc_set_ac97_ops(NULL);
error_ac97_ops: + if (fsl_ssi_is_ac97(ssi_private)) + mutex_destroy(&ssi_private->ac97_reg_lock); + if (ssi_private->soc->imx) fsl_ssi_imx_clean(pdev, ssi_private);
@@ -1681,8 +1697,10 @@ static int fsl_ssi_remove(struct platform_device *pdev) if (ssi_private->soc->imx) fsl_ssi_imx_clean(pdev, ssi_private);
- if (fsl_ssi_is_ac97(ssi_private)) + if (fsl_ssi_is_ac97(ssi_private)) { snd_soc_set_ac97_ops(NULL); + mutex_destroy(&ssi_private->ac97_reg_lock); + }
return 0; }