[Sound-open-firmware] [PATCH] apl-ssp: fix capture double speed issue

[Liam Girdwood]

On Wed, 2018-03-14 at 23:12 +0800, Keyon Jie wrote:
> Previously TFT and RFT are set to 0s which means we are using
> threshold level 1, where interrupt asserts for every valid bits
> of each slot(e.g. for s16_le capture, interrupts assert for
> each 16 bits), but DMAC will treat it as notification of one
> full sample(e.g. 32 bits for s16_le stereo) and read those all
> bits, this will lead to capture with double speed at format
> s16_le stereo.
> 
> Here add handle for FIFO trigger Threshold level, set them to
> bytes for each full sample(active_slots * valid_bits / 8), and
> the issue is fixed.
> 
> Signed-off-by: Keyon Jie <yang.jie at linux.intel.com>
> ---
>  src/drivers/apl-ssp.c | 25 +++++++++++++++++++++++++
>  1 file changed, 25 insertions(+)
> 
> diff --git a/src/drivers/apl-ssp.c b/src/drivers/apl-ssp.c
> index 1ee107c..ecf70fb 100644
> --- a/src/drivers/apl-ssp.c
> +++ b/src/drivers/apl-ssp.c
> @@ -43,6 +43,19 @@
>  #define trace_ssp_error(__e)	trace_error(TRACE_CLASS_SSP, __e)
>  #define tracev_ssp(__e)	tracev_event(TRACE_CLASS_SSP, __e)
>  
> +/* FIXME: move this to a helper and optimize */
> +static int hweight_32(uint32_t mask)

count_set_bits32() and can you move to lib/lib.c probably separate patch too.

> +{
> +	int i;
> +	int count = 0;
> +
> +	for (i = 0; i < 32; i++) {
> +		count += mask & 1;
> +		mask >>= 1;
> +	}
> +	return count;
> +}
> +
>  /* save SSP context prior to entering D3 */
>  static int ssp_context_store(struct dai *dai)
>  {
> @@ -96,6 +109,9 @@ static inline int ssp_set_config(struct dai *dai,
>  	uint32_t dummy_stop;
>  	uint32_t frame_len = 0;
>  	uint32_t bdiv_min;
> +	uint32_t active_tx_slots = 2;
> +	uint32_t active_rx_slots = 2;

why do we use 2 as default value, for stereo. ? 

This value should always be set based on channel mask so I would set to 0 here
and check that it's not 0 later on (return error and produce trace if 0).

> +
>  	bool inverted_frame = false;
>  	int ret = 0;
>  
> @@ -353,6 +369,9 @@ static inline int ssp_set_config(struct dai *dai,
>  		sspsp |= SSPSP_SFRMP(!inverted_frame);
>  		sspsp |= SSPSP_FSRT;
>  
> +		active_tx_slots = hweight_32(config->tx_slot_mask);
> +		active_rx_slots = hweight_32(config->rx_slot_mask);
> +
>  		break;
>  	case SOF_DAI_FMT_DSP_B:
>  
> @@ -371,6 +390,9 @@ static inline int ssp_set_config(struct dai *dai,
>  		 */
>  		sspsp |= SSPSP_SFRMP(!inverted_frame);
>  
> +		active_tx_slots = hweight_32(config->tx_slot_mask);
> +		active_rx_slots = hweight_32(config->rx_slot_mask);
> +
>  		break;
>  	default:
>  		trace_ssp_error("eca");
> @@ -408,6 +430,9 @@ static inline int ssp_set_config(struct dai *dai,
>  	/* bypass divider for MCLK */
>  	mdivr = 0x00000fff;
>  
> +	sscr3 |= SSCR3_TX(active_tx_slots * config->sample_valid_bits / 8) |
> +		 SSCR3_RX(active_rx_slots * config->sample_valid_bits / 8);
> +
>  	trace_ssp("coe");
>  	ssp_write(dai, SSCR0, sscr0);
>  	ssp_write(dai, SSCR1, sscr1);