ASoC: stm32: sai: Fix DMA burst size

[sfrench/cifs-2.6.git] / sound / soc / stm / stm32_sai_sub.c

diff --git a/sound/soc/stm/stm32_sai_sub.c b/sound/soc/stm/stm32_sai_sub.c
index 90d43961389977f470a5c870d8678cdbd60a1cfe..dde8ddf9e777b04e5d23850f42f51150a26f6278 100644 (file)
--- a/sound/soc/stm/stm32_sai_sub.c
+++ b/sound/soc/stm/stm32_sai_sub.c
@@ -184,7 +184,6 @@ static const struct regmap_config stm32_sai_sub_regmap_config_h7 = {
 static irqreturn_t stm32_sai_isr(int irq, void *devid)
 {
        struct stm32_sai_sub_data *sai = (struct stm32_sai_sub_data *)devid;
-       struct snd_pcm_substream *substream = sai->substream;
        struct platform_device *pdev = sai->pdev;
        unsigned int sr, imr, flags;
        snd_pcm_state_t status = SNDRV_PCM_STATE_RUNNING;
@@ -199,6 +198,11 @@ static irqreturn_t stm32_sai_isr(int irq, void *devid)
        regmap_update_bits(sai->regmap, STM_SAI_CLRFR_REGX, SAI_XCLRFR_MASK,
                           SAI_XCLRFR_MASK);
 
+       if (!sai->substream) {
+               dev_err(&pdev->dev, "Device stopped. Spurious IRQ 0x%x\n", sr);
+               return IRQ_NONE;
+       }
+
        if (flags & SAI_XIMR_OVRUDRIE) {
                dev_err(&pdev->dev, "IRQ %s\n",
                        STM_SAI_IS_PLAYBACK(sai) ? "underrun" : "overrun");
@@ -227,9 +231,9 @@ static irqreturn_t stm32_sai_isr(int irq, void *devid)
        }
 
        if (status != SNDRV_PCM_STATE_RUNNING) {
-               snd_pcm_stream_lock(substream);
-               snd_pcm_stop(substream, SNDRV_PCM_STATE_XRUN);
-               snd_pcm_stream_unlock(substream);
+               snd_pcm_stream_lock(sai->substream);
+               snd_pcm_stop(sai->substream, SNDRV_PCM_STATE_XRUN);
+               snd_pcm_stream_unlock(sai->substream);
        }
 
        return IRQ_HANDLED;
@@ -442,12 +446,16 @@ static int stm32_sai_set_config(struct snd_soc_dai *cpu_dai,
 {
        struct stm32_sai_sub_data *sai = snd_soc_dai_get_drvdata(cpu_dai);
        int cr1, cr1_mask, ret;
-       int fth = STM_SAI_FIFO_TH_HALF;
 
-       /* FIFO config */
+       /*
+        * DMA bursts increment is set to 4 words.
+        * SAI fifo threshold is set to half fifo, to keep enough space
+        * for DMA incoming bursts.
+        */
        regmap_update_bits(sai->regmap, STM_SAI_CR2_REGX,
                           SAI_XCR2_FFLUSH | SAI_XCR2_FTH_MASK,
-                          SAI_XCR2_FFLUSH | SAI_XCR2_FTH_SET(fth));
+                          SAI_XCR2_FFLUSH |
+                          SAI_XCR2_FTH_SET(STM_SAI_FIFO_TH_HALF));
 
        /* Mode, data format and channel config */
        cr1 = SAI_XCR1_PRTCFG_SET(SAI_FREE_PROTOCOL);
@@ -481,10 +489,6 @@ static int stm32_sai_set_config(struct snd_soc_dai *cpu_dai,
                return ret;
        }
 
-       /* DMA config */
-       sai->dma_params.maxburst = STM_SAI_FIFO_SIZE * fth / sizeof(u32);
-       snd_soc_dai_set_dma_data(cpu_dai, substream, (void *)&sai->dma_params);
-
        return 0;
 }
 
@@ -727,7 +731,12 @@ static int stm32_sai_dai_probe(struct snd_soc_dai *cpu_dai)
        struct stm32_sai_sub_data *sai = dev_get_drvdata(cpu_dai->dev);
 
        sai->dma_params.addr = (dma_addr_t)(sai->phys_addr + STM_SAI_DR_REGX);
-       sai->dma_params.maxburst = 1;
+       /*
+        * DMA supports 4, 8 or 16 burst sizes. Burst size 4 is the best choice,
+        * as it allows bytes, half-word and words transfers. (See DMA fifos
+        * constraints).
+        */
+       sai->dma_params.maxburst = 4;
        /* Buswidth will be set by framework at runtime */
        sai->dma_params.addr_width = DMA_SLAVE_BUSWIDTH_UNDEFINED;