1 files changed, 70 insertions, 11 deletions

diff --git a/sound/soc/fsl/fsl_ssi.c b/sound/soc/fsl/fsl_ssi.c
index ed8de1035cda..632ecc0e3956 100644
--- a/sound/soc/fsl/fsl_ssi.c
+++ b/sound/soc/fsl/fsl_ssi.c
@@ -137,6 +137,7 @@ static bool fsl_ssi_volatile_reg(struct device *dev, unsigned int reg)
 	case CCSR_SSI_SACDAT:
 	case CCSR_SSI_SATAG:
 	case CCSR_SSI_SACCST:
+	case CCSR_SSI_SOR:
 		return true;
 	default:
 		return false;
@@ -261,6 +262,7 @@ struct fsl_ssi_private {
 	struct fsl_ssi_dbg dbg_stats;
 
 	const struct fsl_ssi_soc_data *soc;
+	struct device *dev;
 };
 
 /*
@@ -400,6 +402,26 @@ static void fsl_ssi_rxtx_config(struct fsl_ssi_private *ssi_private,
 }
 
 /*
+ * Clear RX or TX FIFO to remove samples from the previous
+ * stream session which may be still present in the FIFO and
+ * may introduce bad samples and/or channel slipping.
+ *
+ * Note: The SOR is not documented in recent IMX datasheet, but
+ * is described in IMX51 reference manual at section 56.3.3.15.
+ */
+static void fsl_ssi_fifo_clear(struct fsl_ssi_private *ssi_private,
+		bool is_rx)
+{
+	if (is_rx) {
+		regmap_update_bits(ssi_private->regs, CCSR_SSI_SOR,
+			CCSR_SSI_SOR_RX_CLR, CCSR_SSI_SOR_RX_CLR);
+	} else {
+		regmap_update_bits(ssi_private->regs, CCSR_SSI_SOR,
+			CCSR_SSI_SOR_TX_CLR, CCSR_SSI_SOR_TX_CLR);
+	}
+}
+
+/*
  * Calculate the bits that have to be disabled for the current stream that is
  * getting disabled. This keeps the bits enabled that are necessary for the
  * second stream to work if 'stream_active' is true.
@@ -474,9 +496,11 @@ static void fsl_ssi_config(struct fsl_ssi_private *ssi_private, bool enable,
 	 * (online configuration)
 	 */
 	if (enable) {
-		regmap_update_bits(regs, CCSR_SSI_SIER, vals->sier, vals->sier);
+		fsl_ssi_fifo_clear(ssi_private, vals->scr & CCSR_SSI_SCR_RE);
+
 		regmap_update_bits(regs, CCSR_SSI_SRCR, vals->srcr, vals->srcr);
 		regmap_update_bits(regs, CCSR_SSI_STCR, vals->stcr, vals->stcr);
+		regmap_update_bits(regs, CCSR_SSI_SIER, vals->sier, vals->sier);
 	} else {
 		u32 sier;
 		u32 srcr;
@@ -506,8 +530,40 @@ static void fsl_ssi_config(struct fsl_ssi_private *ssi_private, bool enable,
 
 config_done:
 	/* Enabling of subunits is done after configuration */
-	if (enable)
+	if (enable) {
+		if (ssi_private->use_dma && (vals->scr & CCSR_SSI_SCR_TE)) {
+			/*
+			 * Be sure the Tx FIFO is filled when TE is set.
+			 * Otherwise, there are some chances to start the
+			 * playback with some void samples inserted first,
+			 * generating a channel slip.
+			 *
+			 * First, SSIEN must be set, to let the FIFO be filled.
+			 *
+			 * Notes:
+			 * - Limit this fix to the DMA case until FIQ cases can
+			 *   be tested.
+			 * - Limit the length of the busy loop to not lock the
+			 *   system too long, even if 1-2 loops are sufficient
+			 *   in general.
+			 */
+			int i;
+			int max_loop = 100;
+			regmap_update_bits(regs, CCSR_SSI_SCR,
+					CCSR_SSI_SCR_SSIEN, CCSR_SSI_SCR_SSIEN);
+			for (i = 0; i < max_loop; i++) {
+				u32 sfcsr;
+				regmap_read(regs, CCSR_SSI_SFCSR, &sfcsr);
+				if (CCSR_SSI_SFCSR_TFCNT0(sfcsr))
+					break;
+			}
+			if (i == max_loop) {
+				dev_err(ssi_private->dev,
+					"Timeout waiting TX FIFO filling\n");
+			}
+		}
 		regmap_update_bits(regs, CCSR_SSI_SCR, vals->scr, vals->scr);
+	}
 }
 
 
@@ -670,6 +726,15 @@ static int fsl_ssi_set_bclk(struct snd_pcm_substream *substream,
 	if (IS_ERR(ssi_private->baudclk))
 		return -EINVAL;
 
+	/*
+	 * Hardware limitation: The bclk rate must be
+	 * never greater than 1/5 IPG clock rate
+	 */
+	if (freq * 5 > clk_get_rate(ssi_private->clk)) {
+		dev_err(cpu_dai->dev, "bitclk > ipgclk/5\n");
+		return -EINVAL;
+	}
+
 	baudclk_is_used = ssi_private->baudclk_streams & ~(BIT(substream->stream));
 
 	/* It should be already enough to divide clock by setting pm alone */
@@ -686,13 +751,6 @@ static int fsl_ssi_set_bclk(struct snd_pcm_substream *substream,
 		else
 			clkrate = clk_round_rate(ssi_private->baudclk, tmprate);
 
-		/*
-		 * Hardware limitation: The bclk rate must be
-		 * never greater than 1/5 IPG clock rate
-		 */
-		if (clkrate * 5 > clk_get_rate(ssi_private->clk))
-			continue;
-
 		clkrate /= factor;
 		afreq = clkrate / (i + 1);
 
@@ -1158,14 +1216,14 @@ static struct snd_soc_dai_driver fsl_ssi_dai_template = {
 	.playback = {
 		.stream_name = "CPU-Playback",
 		.channels_min = 1,
-		.channels_max = 2,
+		.channels_max = 32,
 		.rates = FSLSSI_I2S_RATES,
 		.formats = FSLSSI_I2S_FORMATS,
 	},
 	.capture = {
 		.stream_name = "CPU-Capture",
 		.channels_min = 1,
-		.channels_max = 2,
+		.channels_max = 32,
 		.rates = FSLSSI_I2S_RATES,
 		.formats = FSLSSI_I2S_FORMATS,
 	},
@@ -1402,6 +1460,7 @@ static int fsl_ssi_probe(struct platform_device *pdev)
 	}
 
 	ssi_private->soc = of_id->data;
+	ssi_private->dev = &pdev->dev;
 
 	sprop = of_get_property(np, "fsl,mode", NULL);
 	if (sprop) {