[alsa-devel] [PATCH 6/6] ASoC: davinci-mcasp: Add overrun/underrun event handling
Peter Ujfalusi
peter.ujfalusi at ti.com
Mon Nov 10 11:32:20 CET 2014
From: Misael Lopez Cruz <misael.lopez at ti.com>
An underrun (playback) event occurs when the serializer transfer
data from the XRBUF buffer to the XRSR shift register, but the
XRBUF hasn't been filled. Similarly, the overrun (capture) event
occurs when data from the XRSR shift register is transferred to
the XRBUF but it hasn't been read yet.
These events are handled as XRUN events that cause the pcm to stop.
The stream has to be explicitly restarted by the userspace which
ensures that after stopping/starting McASP the data transfer is
aligned with DMA. The other possibility was to internally stop and
start McASP without DMA even knowing about it.
Signed-off-by: Misael Lopez Cruz <misael.lopez at ti.com>
Signed-off-by: Peter Ujfalusi <peter.ujfalusi at ti.com>
---
.../bindings/sound/davinci-mcasp-audio.txt | 2 +-
sound/soc/davinci/davinci-mcasp.c | 91 ++++++++++++++++++++++
sound/soc/davinci/davinci-mcasp.h | 10 +++
3 files changed, 102 insertions(+), 1 deletion(-)
diff --git a/Documentation/devicetree/bindings/sound/davinci-mcasp-audio.txt b/Documentation/devicetree/bindings/sound/davinci-mcasp-audio.txt
index 60ca07996458..46bc9829c71a 100644
--- a/Documentation/devicetree/bindings/sound/davinci-mcasp-audio.txt
+++ b/Documentation/devicetree/bindings/sound/davinci-mcasp-audio.txt
@@ -32,7 +32,7 @@ Optional properties:
- rx-num-evt : FIFO levels.
- sram-size-playback : size of sram to be allocated during playback
- sram-size-capture : size of sram to be allocated during capture
-- interrupts : Interrupt numbers for McASP, currently not used by the driver
+- interrupts : Interrupt numbers for McASP
- interrupt-names : Known interrupt names are "tx" and "rx"
- pinctrl-0: Should specify pin control group used for this controller.
- pinctrl-names: Should contain only one value - "default", for more details
diff --git a/sound/soc/davinci/davinci-mcasp.c b/sound/soc/davinci/davinci-mcasp.c
index 6b15a974f585..a0bb17f5ebf3 100644
--- a/sound/soc/davinci/davinci-mcasp.c
+++ b/sound/soc/davinci/davinci-mcasp.c
@@ -70,6 +70,7 @@ struct davinci_mcasp {
void __iomem *base;
u32 fifo_base;
struct device *dev;
+ struct snd_pcm_substream *substreams[2];
/* McASP specific data */
int tdm_slots;
@@ -185,6 +186,9 @@ static void mcasp_start_rx(struct davinci_mcasp *mcasp)
mcasp_set_ctl_reg(mcasp, DAVINCI_MCASP_GBLCTLR_REG, RXFSRST);
if (mcasp_is_synchronous(mcasp))
mcasp_set_ctl_reg(mcasp, DAVINCI_MCASP_GBLCTLX_REG, TXFSRST);
+
+ /* enable rececive overrun IRQ */
+ mcasp_set_bits(mcasp, DAVINCI_MCASP_EVTCTLR_REG, ROVRN);
}
static void mcasp_start_tx(struct davinci_mcasp *mcasp)
@@ -214,6 +218,9 @@ static void mcasp_start_tx(struct davinci_mcasp *mcasp)
mcasp_set_ctl_reg(mcasp, DAVINCI_MCASP_GBLCTLX_REG, TXSMRST);
/* Release Frame Sync generator */
mcasp_set_ctl_reg(mcasp, DAVINCI_MCASP_GBLCTLX_REG, TXFSRST);
+
+ /* enable transmit underrun IRQ */
+ mcasp_set_bits(mcasp, DAVINCI_MCASP_EVTCTLX_REG, XUNDRN);
}
static void davinci_mcasp_start(struct davinci_mcasp *mcasp, int stream)
@@ -228,6 +235,9 @@ static void davinci_mcasp_start(struct davinci_mcasp *mcasp, int stream)
static void mcasp_stop_rx(struct davinci_mcasp *mcasp)
{
+ /* disable IRQ sources */
+ mcasp_clr_bits(mcasp, DAVINCI_MCASP_EVTCTLR_REG, ROVRN);
+
/*
* In synchronous mode stop the TX clocks if no other stream is
* running
@@ -249,6 +259,9 @@ static void mcasp_stop_tx(struct davinci_mcasp *mcasp)
{
u32 val = 0;
+ /* disable IRQ sources */
+ mcasp_clr_bits(mcasp, DAVINCI_MCASP_EVTCTLX_REG, XUNDRN);
+
/*
* In synchronous mode keep TX clocks running if the capture stream is
* still running.
@@ -276,6 +289,52 @@ static void davinci_mcasp_stop(struct davinci_mcasp *mcasp, int stream)
mcasp_stop_rx(mcasp);
}
+static irqreturn_t davinci_mcasp_tx_irq_handler(int irq, void *data)
+{
+ struct davinci_mcasp *mcasp = (struct davinci_mcasp *)data;
+ struct snd_pcm_substream *substream;
+ u32 stat;
+
+ stat = mcasp_get_reg(mcasp, DAVINCI_MCASP_TXSTAT_REG);
+ if (stat & XUNDRN) {
+ dev_warn(mcasp->dev, "Transmit buffer underflow\n");
+ substream = mcasp->substreams[SNDRV_PCM_STREAM_PLAYBACK];
+ if (substream) {
+ snd_pcm_stream_lock_irq(substream);
+ if (snd_pcm_running(substream))
+ snd_pcm_stop(substream, SNDRV_PCM_STATE_XRUN);
+ snd_pcm_stream_unlock_irq(substream);
+ }
+ }
+
+ mcasp_set_reg(mcasp, DAVINCI_MCASP_TXSTAT_REG, stat);
+
+ return IRQ_HANDLED;
+}
+
+static irqreturn_t davinci_mcasp_rx_irq_handler(int irq, void *data)
+{
+ struct davinci_mcasp *mcasp = (struct davinci_mcasp *)data;
+ struct snd_pcm_substream *substream;
+ u32 stat;
+
+ stat = mcasp_get_reg(mcasp, DAVINCI_MCASP_RXSTAT_REG);
+ if (stat & ROVRN) {
+ dev_warn(mcasp->dev, "Receive buffer overflow\n");
+ substream = mcasp->substreams[SNDRV_PCM_STREAM_CAPTURE];
+ if (substream) {
+ snd_pcm_stream_lock_irq(substream);
+ if (snd_pcm_running(substream))
+ snd_pcm_stop(substream, SNDRV_PCM_STATE_XRUN);
+ snd_pcm_stream_unlock_irq(substream);
+ }
+ }
+
+ mcasp_set_reg(mcasp, DAVINCI_MCASP_RXSTAT_REG, stat);
+
+ return IRQ_HANDLED;
+}
+
static int davinci_mcasp_set_dai_fmt(struct snd_soc_dai *cpu_dai,
unsigned int fmt)
{
@@ -878,6 +937,8 @@ static int davinci_mcasp_startup(struct snd_pcm_substream *substream,
u32 max_channels = 0;
int i, dir;
+ mcasp->substreams[substream->stream] = substream;
+
if (mcasp->op_mode == DAVINCI_MCASP_DIT_MODE)
return 0;
@@ -916,6 +977,8 @@ static void davinci_mcasp_shutdown(struct snd_pcm_substream *substream,
{
struct davinci_mcasp *mcasp = snd_soc_dai_get_drvdata(cpu_dai);
+ mcasp->substreams[substream->stream] = NULL;
+
if (mcasp->op_mode == DAVINCI_MCASP_DIT_MODE)
return;
@@ -1266,6 +1329,8 @@ static int davinci_mcasp_probe(struct platform_device *pdev)
struct resource *mem, *ioarea, *res, *dat;
struct davinci_mcasp_pdata *pdata;
struct davinci_mcasp *mcasp;
+ char *irq_name;
+ int irq;
int ret;
if (!pdev->dev.platform_data && !pdev->dev.of_node) {
@@ -1346,6 +1411,32 @@ static int davinci_mcasp_probe(struct platform_device *pdev)
mcasp->dev = &pdev->dev;
+ irq = platform_get_irq_byname(pdev, "rx");
+ if (irq >= 0) {
+ irq_name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "%s_rx\n",
+ dev_name(&pdev->dev));
+ ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
+ davinci_mcasp_rx_irq_handler,
+ IRQF_ONESHOT, irq_name, mcasp);
+ if (ret) {
+ dev_err(&pdev->dev, "RX IRQ request failed\n");
+ goto err;
+ }
+ }
+
+ irq = platform_get_irq_byname(pdev, "tx");
+ if (irq >= 0) {
+ irq_name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "%s_tx\n",
+ dev_name(&pdev->dev));
+ ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
+ davinci_mcasp_tx_irq_handler,
+ IRQF_ONESHOT, irq_name, mcasp);
+ if (ret) {
+ dev_err(&pdev->dev, "TX IRQ request failed\n");
+ goto err;
+ }
+ }
+
dat = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dat");
if (dat)
mcasp->dat_port = true;
diff --git a/sound/soc/davinci/davinci-mcasp.h b/sound/soc/davinci/davinci-mcasp.h
index 9737108f0305..cbba1daa25ec 100644
--- a/sound/soc/davinci/davinci-mcasp.h
+++ b/sound/soc/davinci/davinci-mcasp.h
@@ -285,6 +285,16 @@
#define TXDATADMADIS BIT(0)
/*
+ * DAVINCI_MCASP_EVTCTLR_REG - Receiver Interrupt Control Register Bits
+ */
+#define ROVRN BIT(0)
+
+/*
+ * DAVINCI_MCASP_EVTCTLX_REG - Transmitter Interrupt Control Register Bits
+ */
+#define XUNDRN BIT(0)
+
+/*
* DAVINCI_MCASP_W[R]FIFOCTL - Write/Read FIFO Control Register bits
*/
#define FIFO_ENABLE BIT(16)
--
2.1.3
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