ASoC: fsl_esai: recover the channel swap after xrun

There is chip errata ERR008000, the reference doc is
(https://www.nxp.com/docs/en/errata/IMX6DQCE.pdf),

The issue is "While using ESAI transmit or receive and
an underrun/overrun happens, channel swap may occur.
The only recovery mechanism is to reset the ESAI."

This issue exist in imx3/imx5/imx6(partial) series.

In this commit add a tasklet to handle reset of ESAI
after xrun happens to recover the channel swap.

Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
Acked-by: Nicolin Chen <nicoleotsuka@gmail.com>
Link: https://lore.kernel.org/r/326035cb99975361699d9ed748054b08bc06a341.1562842206.git.shengjiu.wang@nxp.com
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/sound/soc/fsl/fsl_esai.c b/sound/soc/fsl/fsl_esai.c
index ab460d6..4ce8ac7 100644 (file)
--- a/sound/soc/fsl/fsl_esai.c
+++ b/sound/soc/fsl/fsl_esai.c
@@ -32,6 +32,7 @@
  * @extalclk: esai clock source to derive HCK, SCK and FS
  * @fsysclk: system clock source to derive HCK, SCK and FS
  * @spbaclk: SPBA clock (optional, depending on SoC design)
+ * @task: tasklet to handle the reset operation
  * @fifo_depth: depth of tx/rx FIFO
  * @slot_width: width of each DAI slot
  * @slots: number of slots
@@ -42,6 +43,7 @@
  * @sck_div: if using PSR/PM dividers for SCKx clock
  * @slave_mode: if fully using DAI slave mode
  * @synchronous: if using tx/rx synchronous mode
+ * @reset_at_xrun: flags for enable reset operaton
  * @name: driver name
  */
 struct fsl_esai {
@@ -53,6 +55,7 @@ struct fsl_esai {
        struct clk *extalclk;
        struct clk *fsysclk;
        struct clk *spbaclk;
+       struct tasklet_struct task;
        u32 fifo_depth;
        u32 slot_width;
        u32 slots;
@@ -65,6 +68,7 @@ struct fsl_esai {
        bool sck_div[2];
        bool slave_mode;
        bool synchronous;
+       bool reset_at_xrun;
        char name[32];
 };
 
@@ -73,8 +77,16 @@ static irqreturn_t esai_isr(int irq, void *devid)
        struct fsl_esai *esai_priv = (struct fsl_esai *)devid;
        struct platform_device *pdev = esai_priv->pdev;
        u32 esr;
+       u32 saisr;
 
        regmap_read(esai_priv->regmap, REG_ESAI_ESR, &esr);
+       regmap_read(esai_priv->regmap, REG_ESAI_SAISR, &saisr);
+
+       if ((saisr & (ESAI_SAISR_TUE | ESAI_SAISR_ROE)) &&
+           esai_priv->reset_at_xrun) {
+               dev_dbg(&pdev->dev, "reset module for xrun\n");
+               tasklet_schedule(&esai_priv->task);
+       }
 
        if (esr & ESAI_ESR_TINIT_MASK)
                dev_dbg(&pdev->dev, "isr: Transmission Initialized\n");
@@ -635,11 +647,18 @@ static void fsl_esai_trigger_start(struct fsl_esai *esai_priv, bool tx)
                           ESAI_xSMB_xS_MASK, ESAI_xSMB_xS(mask));
        regmap_update_bits(esai_priv->regmap, REG_ESAI_xSMA(tx),
                           ESAI_xSMA_xS_MASK, ESAI_xSMA_xS(mask));
+
+       /* Enable Exception interrupt */
+       regmap_update_bits(esai_priv->regmap, REG_ESAI_xCR(tx),
+                          ESAI_xCR_xEIE_MASK, ESAI_xCR_xEIE);
 }
 
 static void fsl_esai_trigger_stop(struct fsl_esai *esai_priv, bool tx)
 {
        regmap_update_bits(esai_priv->regmap, REG_ESAI_xCR(tx),
+                          ESAI_xCR_xEIE_MASK, 0);
+
+       regmap_update_bits(esai_priv->regmap, REG_ESAI_xCR(tx),
                           tx ? ESAI_xCR_TE_MASK : ESAI_xCR_RE_MASK, 0);
        regmap_update_bits(esai_priv->regmap, REG_ESAI_xSMA(tx),
                           ESAI_xSMA_xS_MASK, 0);
@@ -653,6 +672,51 @@ static void fsl_esai_trigger_stop(struct fsl_esai *esai_priv, bool tx)
                           ESAI_xFCR_xFR, 0);
 }
 
+static void fsl_esai_hw_reset(unsigned long arg)
+{
+       struct fsl_esai *esai_priv = (struct fsl_esai *)arg;
+       bool tx = true, rx = false, enabled[2];
+       u32 tfcr, rfcr;
+
+       /* Save the registers */
+       regmap_read(esai_priv->regmap, REG_ESAI_TFCR, &tfcr);
+       regmap_read(esai_priv->regmap, REG_ESAI_RFCR, &rfcr);
+       enabled[tx] = tfcr & ESAI_xFCR_xFEN;
+       enabled[rx] = rfcr & ESAI_xFCR_xFEN;
+
+       /* Stop the tx & rx */
+       fsl_esai_trigger_stop(esai_priv, tx);
+       fsl_esai_trigger_stop(esai_priv, rx);
+
+       /* Reset the esai, and ignore return value */
+       fsl_esai_hw_init(esai_priv);
+
+       /* Enforce ESAI personal resets for both TX and RX */
+       regmap_update_bits(esai_priv->regmap, REG_ESAI_TCR,
+                          ESAI_xCR_xPR_MASK, ESAI_xCR_xPR);
+       regmap_update_bits(esai_priv->regmap, REG_ESAI_RCR,
+                          ESAI_xCR_xPR_MASK, ESAI_xCR_xPR);
+
+       /* Restore registers by regcache_sync, and ignore return value */
+       fsl_esai_register_restore(esai_priv);
+
+       /* Remove ESAI personal resets by configuring PCRC and PRRC also */
+       regmap_update_bits(esai_priv->regmap, REG_ESAI_TCR,
+                          ESAI_xCR_xPR_MASK, 0);
+       regmap_update_bits(esai_priv->regmap, REG_ESAI_RCR,
+                          ESAI_xCR_xPR_MASK, 0);
+       regmap_update_bits(esai_priv->regmap, REG_ESAI_PRRC,
+                          ESAI_PRRC_PDC_MASK, ESAI_PRRC_PDC(ESAI_GPIO));
+       regmap_update_bits(esai_priv->regmap, REG_ESAI_PCRC,
+                          ESAI_PCRC_PC_MASK, ESAI_PCRC_PC(ESAI_GPIO));
+
+       /* Restart tx / rx, if they already enabled */
+       if (enabled[tx])
+               fsl_esai_trigger_start(esai_priv, tx);
+       if (enabled[rx])
+               fsl_esai_trigger_start(esai_priv, rx);
+}
+
 static int fsl_esai_trigger(struct snd_pcm_substream *substream, int cmd,
                            struct snd_soc_dai *dai)
 {
@@ -857,6 +921,10 @@ static int fsl_esai_probe(struct platform_device *pdev)
        esai_priv->pdev = pdev;
        snprintf(esai_priv->name, sizeof(esai_priv->name), "%pOFn", np);
 
+       if (of_device_is_compatible(np, "fsl,vf610-esai") ||
+           of_device_is_compatible(np, "fsl,imx35-esai"))
+               esai_priv->reset_at_xrun = true;
+
        /* Get the addresses and IRQ */
        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        regs = devm_ioremap_resource(&pdev->dev, res);
@@ -956,6 +1024,9 @@ static int fsl_esai_probe(struct platform_device *pdev)
                return ret;
        }
 
+       tasklet_init(&esai_priv->task, fsl_esai_hw_reset,
+                    (unsigned long)esai_priv);
+
        pm_runtime_enable(&pdev->dev);
 
        regcache_cache_only(esai_priv->regmap, true);
@@ -969,7 +1040,10 @@ static int fsl_esai_probe(struct platform_device *pdev)
 
 static int fsl_esai_remove(struct platform_device *pdev)
 {
+       struct fsl_esai *esai_priv = platform_get_drvdata(pdev);
+
        pm_runtime_disable(&pdev->dev);
+       tasklet_kill(&esai_priv->task);
 
        return 0;
 }