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>
(cherry picked from commit d3818ba35e4cbb6a3fa769eb83ceb7335b7c19e6)

diff --git a/sound/soc/fsl/fsl_ssi.c b/sound/soc/fsl/fsl_ssi.c
index ce18518add3d92851515189fe4550aa6acae5078..46f574895f7397a460e62e6c5861a3e755f3168e 100644 (file)
--- 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);