ENGR00295423-2 ASoC: fsl_ssi: Don't set clock rate in hw_params()

Leaving clk_set_rate() in hw_params() is a bit dangerous when handling two
substreams. So we let set_sysclk() finish the clk_set_rate() directly.

This patch also adds spinlock to protect the baud clock configuration so
that it won't be broken during race.

Signed-off-by: Nicolin Chen <Guangyu.Chen@freescale.com>

1 files changed, 31 insertions, 18 deletions

diff --git a/sound/soc/fsl/fsl_ssi.c b/sound/soc/fsl/fsl_ssi.c
index ce18518add3d..46f574895f73 100644
--- a/sound/soc/fsl/fsl_ssi.c
+++ b/sound/soc/fsl/fsl_ssi.c
@@ -134,11 +134,12 @@ struct fsl_ssi_private {
         struct device_attribute dev_attr;
         struct platform_device *pdev;
 
-        unsigned long sysrate;
         bool new_binding;
         bool ssi_on_imx;
         bool use_dual_fifo;
+        bool baudclk_locked;
         u8 i2s_mode;
+        spinlock_t baudclk_lock;
         struct clk *coreclk;
         struct clk *clk;
         struct snd_dmaengine_dai_dma_data dma_params_tx;
@@ -330,6 +331,7 @@ static int fsl_ssi_startup(struct snd_pcm_substream *substream,
         struct fsl_ssi_private *ssi_private =
                 snd_soc_dai_get_drvdata(rtd->cpu_dai);
         int synchronous = ssi_private->cpu_dai_drv.symmetric_rates;
+        unsigned long flags;
 
         if (ssi_private->ssi_on_imx) {
                 pm_runtime_get_sync(dai->dev);
@@ -428,6 +430,10 @@ static int fsl_ssi_startup(struct snd_pcm_substream *substream,
                  * this is bad is because at this point, the PCM driver has not
                  * finished initializing the DMA controller.
                  */
+
+                spin_lock_irqsave(&ssi_private->baudclk_lock, flags);
+                ssi_private->baudclk_locked = false;
+                spin_unlock_irqrestore(&ssi_private->baudclk_lock, flags);
         }
 
         return 0;
@@ -456,7 +462,6 @@ static int fsl_ssi_hw_params(struct snd_pcm_substream *substream,
         u32 wl = CCSR_SSI_SxCCR_WL(sample_size);
         int enabled = read_ssi(&ssi->scr) & CCSR_SSI_SCR_SSIEN;
         unsigned int channels = params_channels(hw_params);
-        int ret;
 
         /*
          * If we're in synchronous mode, and the SSI is already enabled,
@@ -465,14 +470,6 @@ static int fsl_ssi_hw_params(struct snd_pcm_substream *substream,
         if (enabled && ssi_private->cpu_dai_drv.symmetric_rates)
                 return 0;
 
-        if (ssi_private->sysrate) {
-                ret = clk_set_rate(ssi_private->clk, ssi_private->sysrate);
-                if (ret) {
-                        dev_err(cpu_dai->dev, "failed to set clock rate\n");
-                        return ret;
-                }
-        }
-
         /*
          * FIXME: The documentation says that SxCCR[WL] should not be
          * modified while the SSI is enabled.  The only time this can
@@ -511,6 +508,7 @@ static int fsl_ssi_trigger(struct snd_pcm_substream *substream, int cmd,
         struct snd_soc_pcm_runtime *rtd = substream->private_data;
         struct fsl_ssi_private *ssi_private = snd_soc_dai_get_drvdata(rtd->cpu_dai);
         struct ccsr_ssi __iomem *ssi = ssi_private->ssi;
+        unsigned long flags;
 
         switch (cmd) {
         case SNDRV_PCM_TRIGGER_START:
@@ -538,8 +536,12 @@ static int fsl_ssi_trigger(struct snd_pcm_substream *substream, int cmd,
                         write_ssi_mask(&ssi->scr, CCSR_SSI_SCR_RE, 0);
                         write_ssi_mask(&ssi->sier, CCSR_SSI_SIER_RDMAE, 0);
                 }
-                if ((read_ssi(&ssi->scr) & (CCSR_SSI_SCR_TE | CCSR_SSI_SCR_RE)) == 0)
+                if ((read_ssi(&ssi->scr) & (CCSR_SSI_SCR_TE | CCSR_SSI_SCR_RE)) == 0) {
                         write_ssi_mask(&ssi->scr, CCSR_SSI_SCR_SSIEN, 0);
+                        spin_lock_irqsave(&ssi_private->baudclk_lock, flags);
+                        ssi_private->baudclk_locked = false;
+                        spin_unlock_irqrestore(&ssi_private->baudclk_lock, flags);
+                }
                 break;
 
         default:
@@ -669,9 +671,9 @@ static int fsl_ssi_set_dai_sysclk(struct snd_soc_dai *cpu_dai,
 {
         struct fsl_ssi_private *ssi_private = snd_soc_dai_get_drvdata(cpu_dai);
         struct ccsr_ssi __iomem *ssi = ssi_private->ssi;
-        int synchronous = ssi_private->cpu_dai_drv.symmetric_rates;
+        int synchronous = ssi_private->cpu_dai_drv.symmetric_rates, ret;
         u32 pm = 999, div2, psr, stccr, mask, afreq, factor, i;
-        unsigned long clkrate, sysrate = 0;
+        unsigned long clkrate, sysrate = 0, baudrate, flags;
         u64 sub, savesub = 100000;
 
         /*
@@ -708,7 +710,7 @@ static int fsl_ssi_set_dai_sysclk(struct snd_soc_dai *cpu_dai,
                 do_div(sub, freq);
 
                 if (sub < savesub) {
-                        ssi_private->sysrate = sysrate;
+                        baudrate = sysrate;
                         savesub = sub;
                         pm = i;
                 }
@@ -734,6 +736,18 @@ static int fsl_ssi_set_dai_sysclk(struct snd_soc_dai *cpu_dai,
         else
                 write_ssi_mask(&ssi->srccr, mask, stccr);
 
+        spin_lock_irqsave(&ssi_private->baudclk_lock, flags);
+        if (!ssi_private->baudclk_locked) {
+                ret = clk_set_rate(ssi_private->clk, baudrate);
+                if (ret) {
+                        spin_unlock_irqrestore(&ssi_private->baudclk_lock, flags);
+                        dev_err(cpu_dai->dev, "failed to set baudclk rate\n");
+                        return -EINVAL;
+                }
+                ssi_private->baudclk_locked = true;
+        }
+        spin_unlock_irqrestore(&ssi_private->baudclk_lock, flags);
+
         return 0;
 }
 
@@ -775,8 +789,6 @@ static void fsl_ssi_shutdown(struct snd_pcm_substream *substream,
                 struct ccsr_ssi __iomem *ssi = ssi_private->ssi;
 
                 write_ssi_mask(&ssi->sier, SIER_FLAGS, 0);
-
-                ssi_private->sysrate = 0;
         }
 
         if (ssi_private->ssi_on_imx) {
@@ -974,6 +986,9 @@ static int fsl_ssi_probe(struct platform_device *pdev)
                 /* Older 8610 DTs didn't have the fifo-depth property */
                 ssi_private->fifo_depth = 8;
 
+        ssi_private->baudclk_locked = false;
+        spin_lock_init(&ssi_private->baudclk_lock);
+
         if (of_device_is_compatible(pdev->dev.of_node, "fsl,imx21-ssi")) {
                 ssi_private->ssi_on_imx = true;
 
@@ -1004,8 +1019,6 @@ static int fsl_ssi_probe(struct platform_device *pdev)
                         ssi_private->ssi_phys + offsetof(struct ccsr_ssi, srx0);
         }
 
-        ssi_private->sysrate = 0;
-
         /* Initialize the the device_attribute structure */
         dev_attr = &ssi_private->dev_attr;
         sysfs_attr_init(&dev_attr->attr);