ALSA: asoc: restrict sample rate and size in Freescale MPC8610 sound drivers

[firefly-linux-kernel-4.4.55.git] / sound / soc / fsl / fsl_ssi.c

diff --git a/sound/soc/fsl/fsl_ssi.c b/sound/soc/fsl/fsl_ssi.c
index 71bff33f5528fe5e34849c06bbc1e88b91fbbcbb..157a7895ffa1befbb2427b121f0bb493c0190b3d 100644 (file)
--- a/sound/soc/fsl/fsl_ssi.c
+++ b/sound/soc/fsl/fsl_ssi.c
@@ -67,6 +67,8 @@
  * @ssi: pointer to the SSI's registers
  * @ssi_phys: physical address of the SSI registers
  * @irq: IRQ of this SSI
+ * @first_stream: pointer to the stream that was opened first
+ * @second_stream: pointer to second stream
  * @dev: struct device pointer
  * @playback: the number of playback streams opened
  * @capture: the number of capture streams opened
@@ -79,6 +81,8 @@ struct fsl_ssi_private {
        struct ccsr_ssi __iomem *ssi;
        dma_addr_t ssi_phys;
        unsigned int irq;
+       struct snd_pcm_substream *first_stream;
+       struct snd_pcm_substream *second_stream;
        struct device *dev;
        unsigned int playback;
        unsigned int capture;
@@ -342,6 +346,49 @@ static int fsl_ssi_startup(struct snd_pcm_substream *substream)
                 */
        }
 
+       if (!ssi_private->first_stream)
+               ssi_private->first_stream = substream;
+       else {
+               /* This is the second stream open, so we need to impose sample
+                * rate and maybe sample size constraints.  Note that this can
+                * cause a race condition if the second stream is opened before
+                * the first stream is fully initialized.
+                *
+                * We provide some protection by checking to make sure the first
+                * stream is initialized, but it's not perfect.  ALSA sometimes
+                * re-initializes the driver with a different sample rate or
+                * size.  If the second stream is opened before the first stream
+                * has received its final parameters, then the second stream may
+                * be constrained to the wrong sample rate or size.
+                *
+                * FIXME: This code does not handle opening and closing streams
+                * repeatedly.  If you open two streams and then close the first
+                * one, you may not be able to open another stream until you
+                * close the second one as well.
+                */
+               struct snd_pcm_runtime *first_runtime =
+                       ssi_private->first_stream->runtime;
+
+               if (!first_runtime->rate || !first_runtime->sample_bits) {
+                       dev_err(substream->pcm->card->dev,
+                               "set sample rate and size in %s stream first\n",
+                               substream->stream == SNDRV_PCM_STREAM_PLAYBACK
+                               ? "capture" : "playback");
+                       return -EAGAIN;
+               }
+
+               snd_pcm_hw_constraint_minmax(substream->runtime,
+                       SNDRV_PCM_HW_PARAM_RATE,
+                       first_runtime->rate, first_runtime->rate);
+
+               snd_pcm_hw_constraint_minmax(substream->runtime,
+                       SNDRV_PCM_HW_PARAM_SAMPLE_BITS,
+                       first_runtime->sample_bits,
+                       first_runtime->sample_bits);
+
+               ssi_private->second_stream = substream;
+       }
+
        if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
                ssi_private->playback++;
 
@@ -371,18 +418,16 @@ static int fsl_ssi_prepare(struct snd_pcm_substream *substream)
        struct fsl_ssi_private *ssi_private = rtd->dai->cpu_dai->private_data;
 
        struct ccsr_ssi __iomem *ssi = ssi_private->ssi;
-       u32 wl;
 
-       wl = CCSR_SSI_SxCCR_WL(snd_pcm_format_width(runtime->format));
+       if (substream == ssi_private->first_stream) {
+               u32 wl;
 
-       clrbits32(&ssi->scr, CCSR_SSI_SCR_SSIEN);
+               /* The SSI should always be disabled at this points (SSIEN=0) */
+               wl = CCSR_SSI_SxCCR_WL(snd_pcm_format_width(runtime->format));
 
-       if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
+               /* In synchronous mode, the SSI uses STCCR for capture */
                clrsetbits_be32(&ssi->stccr, CCSR_SSI_SxCCR_WL_MASK, wl);
-       else
-               clrsetbits_be32(&ssi->srccr, CCSR_SSI_SxCCR_WL_MASK, wl);
-
-       setbits32(&ssi->scr, CCSR_SSI_SCR_SSIEN);
+       }
 
        return 0;
 }
@@ -407,9 +452,13 @@ static int fsl_ssi_trigger(struct snd_pcm_substream *substream, int cmd)
        case SNDRV_PCM_TRIGGER_RESUME:
        case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
                if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
-                       setbits32(&ssi->scr, CCSR_SSI_SCR_TE);
+                       clrbits32(&ssi->scr, CCSR_SSI_SCR_SSIEN);
+                       setbits32(&ssi->scr,
+                               CCSR_SSI_SCR_SSIEN | CCSR_SSI_SCR_TE);
                } else {
-                       setbits32(&ssi->scr, CCSR_SSI_SCR_RE);
+                       clrbits32(&ssi->scr, CCSR_SSI_SCR_SSIEN);
+                       setbits32(&ssi->scr,
+                               CCSR_SSI_SCR_SSIEN | CCSR_SSI_SCR_RE);
 
                        /*
                         * I think we need this delay to allow time for the SSI
@@ -452,6 +501,11 @@ static void fsl_ssi_shutdown(struct snd_pcm_substream *substream)
        if (substream->stream == SNDRV_PCM_STREAM_CAPTURE)
                ssi_private->capture--;
 
+       if (ssi_private->first_stream == substream)
+               ssi_private->first_stream = ssi_private->second_stream;
+
+       ssi_private->second_stream = NULL;
+
        /*
         * If this is the last active substream, disable the SSI and release
         * the IRQ.