[Sound-open-firmware] [PATCH] ssp: Add IRQ handler to SSP port

[Pierre-Louis Bossart]

On 9/20/17 8:58 AM, Liam Girdwood wrote:
> Add an interrupt handler to slear any SSP IRQs. TODO: extend this to
> report XRUNS and other errors.
> 
> Signed-off-by: Liam Girdwood <liam.r.girdwood at linux.intel.com>
> ---
>   src/drivers/ssp.c      | 23 +++++++++++++++++++++++
>   src/include/reef/ssp.h |  6 +++++-
>   2 files changed, 28 insertions(+), 1 deletion(-)
> 
> diff --git a/src/drivers/ssp.c b/src/drivers/ssp.c
> index 6d2c004..547c91c 100644
> --- a/src/drivers/ssp.c
> +++ b/src/drivers/ssp.c
> @@ -370,6 +370,24 @@ static int ssp_trigger(struct dai *dai, int cmd, int direction)
>   	return 0;
>   }
>   
> +/* The IRQ handler allows the SSP port to drain the playback FIFO to make sure
> + * every sample has been played */
> +static void ssp_irq_handler(void *data)
> +{
> +	struct dai *dai = data;
> +	int i;
> +
> +	trace_value(ssp_read(dai, SSSR));
> +
> +	/* empty Rx FIFO */
> +	for (i = 0; i < 16; i++)
> +		ssp_read(dai, SSDR);
> +

I am having a hard-time with this one. Is this really the playback FIFO 
that we are draining if we read from a FIFO? and why do we need to 
drain, it's that what DMAs are for?

> +	/* clear IRQ */
> +	ssp_write(dai, SSSR, ssp_read(dai, SSSR));
> +	platform_interrupt_clear(ssp_irq(dai), 1);
> +}
> +
>   static int ssp_probe(struct dai *dai)
>   {
>   	struct ssp_pdata *ssp;
> @@ -383,6 +401,11 @@ static int ssp_probe(struct dai *dai)
>   	ssp->state[DAI_DIR_PLAYBACK] = COMP_STATE_READY;
>   	ssp->state[DAI_DIR_CAPTURE] = COMP_STATE_READY;
>   
> +	/* register our IRQ handler */
> +	interrupt_register(ssp_irq(dai), ssp_irq_handler, dai);
> +	platform_interrupt_unmask(ssp_irq(dai), 1);
> +	interrupt_enable(ssp_irq(dai));
> +
>   	return 0;
>   }
>   
> diff --git a/src/include/reef/ssp.h b/src/include/reef/ssp.h
> index 70113df..448a0dd 100644
> --- a/src/include/reef/ssp.h
> +++ b/src/include/reef/ssp.h
> @@ -78,7 +78,7 @@ extern const struct dai_ops ssp_ops;
>   #define SSCR0_EDSS	(1 << 20)
>   #define SSCR0_NCS	(1 << 21)
>   #define SSCR0_RIM	(1 << 22)
> -#define SSCR0_TUM	(1 << 23)
> +#define SSCR0_TIM	(1 << 23)
>   #define SSCR0_FRDC(x)	((x - 1) << 24)
>   #define SSCR0_ACS	(1 << 30)
>   #define SSCR0_MOD	(1 << 31)
> @@ -154,6 +154,10 @@ extern const struct dai_ops ssp_ops;
>   #define trace_ssp_error(__e)	trace_error(TRACE_CLASS_SSP, __e)
>   #define tracev_ssp(__e)	tracev_event(TRACE_CLASS_SSP, __e)
>   
> +
> +#define ssp_irq(ssp) \
> +	ssp->plat_data.irq
> +
>   /* SSP private data */
>   struct ssp_pdata {
>   	uint32_t sscr0;
>