Re: [PATCH v2 2/2] mmc: dw_mmc-rockchip: parse rockchip,desired-num-phases from DT

[Jaehoon Chung <jh80.chung@samsung.com>]

Hi Shawn,

On 05/16/2017 03:28 PM, Shawn Lin wrote:
> Currently we unconditionally do tuning for each degree, which
> costs 900ms for each boot and resume.
> 
> May someone argue that this is a question of accuracy VS time. But I
> would say it's a trick of how we need to do decision for our boards.
> If we don't care the time we spend at all, we could definitely do tuning
> for each degree. But when we need to improve the user experience, for
> instance, speed up resuming from S3, we should also have the right to
> do that. This patch add parsing "rockchip,desired-num-phases", for folks
> to specify the number of doing tuning. If not specified, 360 will be used
> as before.
> 
> Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>

Will pick this patch with [PATCH 1/2] after getting acked tags from DT guys.

Best Regards,
Jaehoon Chung

> 
> ---
> 
> Changes in v2:
> - rename property to rockchip,desired-num-phases
> 
>  drivers/mmc/host/dw_mmc-rockchip.c | 48 ++++++++++++++++++++++++--------------
>  1 file changed, 30 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/mmc/host/dw_mmc-rockchip.c b/drivers/mmc/host/dw_mmc-rockchip.c
> index 372fb6e..a3f1c2b 100644
> --- a/drivers/mmc/host/dw_mmc-rockchip.c
> +++ b/drivers/mmc/host/dw_mmc-rockchip.c
> @@ -25,6 +25,7 @@ struct dw_mci_rockchip_priv_data {
>  	struct clk		*drv_clk;
>  	struct clk		*sample_clk;
>  	int			default_sample_phase;
> +	int			num_phases;
>  };
>  
>  static void dw_mci_rk3288_set_ios(struct dw_mci *host, struct mmc_ios *ios)
> @@ -133,8 +134,8 @@ static void dw_mci_rk3288_set_ios(struct dw_mci *host, struct mmc_ios *ios)
>  	}
>  }
>  
> -#define NUM_PHASES			360
> -#define TUNING_ITERATION_TO_PHASE(i)	(DIV_ROUND_UP((i) * 360, NUM_PHASES))
> +#define TUNING_ITERATION_TO_PHASE(i, num_phases) \
> +		(DIV_ROUND_UP((i) * 360, num_phases))
>  
>  static int dw_mci_rk3288_execute_tuning(struct dw_mci_slot *slot, u32 opcode)
>  {
> @@ -159,13 +160,15 @@ static int dw_mci_rk3288_execute_tuning(struct dw_mci_slot *slot, u32 opcode)
>  		return -EIO;
>  	}
>  
> -	ranges = kmalloc_array(NUM_PHASES / 2 + 1, sizeof(*ranges), GFP_KERNEL);
> +	ranges = kmalloc_array(priv->num_phases / 2 + 1,
> +			       sizeof(*ranges), GFP_KERNEL);
>  	if (!ranges)
>  		return -ENOMEM;
>  
>  	/* Try each phase and extract good ranges */
> -	for (i = 0; i < NUM_PHASES; ) {
> -		clk_set_phase(priv->sample_clk, TUNING_ITERATION_TO_PHASE(i));
> +	for (i = 0; i < priv->num_phases; ) {
> +		clk_set_phase(priv->sample_clk,
> +			      TUNING_ITERATION_TO_PHASE(i, priv->num_phases));
>  
>  		v = !mmc_send_tuning(mmc, opcode, NULL);
>  
> @@ -179,7 +182,7 @@ static int dw_mci_rk3288_execute_tuning(struct dw_mci_slot *slot, u32 opcode)
>  		if (v) {
>  			ranges[range_count-1].end = i;
>  			i++;
> -		} else if (i == NUM_PHASES - 1) {
> +		} else if (i == priv->num_phases - 1) {
>  			/* No extra skipping rules if we're at the end */
>  			i++;
>  		} else {
> @@ -188,11 +191,11 @@ static int dw_mci_rk3288_execute_tuning(struct dw_mci_slot *slot, u32 opcode)
>  			 * one since testing bad phases is slow.  Skip
>  			 * 20 degrees.
>  			 */
> -			i += DIV_ROUND_UP(20 * NUM_PHASES, 360);
> +			i += DIV_ROUND_UP(20 * priv->num_phases, 360);
>  
>  			/* Always test the last one */
> -			if (i >= NUM_PHASES)
> -				i = NUM_PHASES - 1;
> +			if (i >= priv->num_phases)
> +				i = priv->num_phases - 1;
>  		}
>  
>  		prev_v = v;
> @@ -210,7 +213,7 @@ static int dw_mci_rk3288_execute_tuning(struct dw_mci_slot *slot, u32 opcode)
>  		range_count--;
>  	}
>  
> -	if (ranges[0].start == 0 && ranges[0].end == NUM_PHASES - 1) {
> +	if (ranges[0].start == 0 && ranges[0].end == priv->num_phases - 1) {
>  		clk_set_phase(priv->sample_clk, priv->default_sample_phase);
>  		dev_info(host->dev, "All phases work, using default phase %d.",
>  			 priv->default_sample_phase);
> @@ -222,7 +225,7 @@ static int dw_mci_rk3288_execute_tuning(struct dw_mci_slot *slot, u32 opcode)
>  		int len = (ranges[i].end - ranges[i].start + 1);
>  
>  		if (len < 0)
> -			len += NUM_PHASES;
> +			len += priv->num_phases;
>  
>  		if (longest_range_len < len) {
>  			longest_range_len = len;
> @@ -230,25 +233,30 @@ static int dw_mci_rk3288_execute_tuning(struct dw_mci_slot *slot, u32 opcode)
>  		}
>  
>  		dev_dbg(host->dev, "Good phase range %d-%d (%d len)\n",
> -			TUNING_ITERATION_TO_PHASE(ranges[i].start),
> -			TUNING_ITERATION_TO_PHASE(ranges[i].end),
> +			TUNING_ITERATION_TO_PHASE(ranges[i].start,
> +						  priv->num_phases),
> +			TUNING_ITERATION_TO_PHASE(ranges[i].end,
> +						  priv->num_phases),
>  			len
>  		);
>  	}
>  
>  	dev_dbg(host->dev, "Best phase range %d-%d (%d len)\n",
> -		TUNING_ITERATION_TO_PHASE(ranges[longest_range].start),
> -		TUNING_ITERATION_TO_PHASE(ranges[longest_range].end),
> +		TUNING_ITERATION_TO_PHASE(ranges[longest_range].start,
> +					  priv->num_phases),
> +		TUNING_ITERATION_TO_PHASE(ranges[longest_range].end,
> +					  priv->num_phases),
>  		longest_range_len
>  	);
>  
>  	middle_phase = ranges[longest_range].start + longest_range_len / 2;
> -	middle_phase %= NUM_PHASES;
> +	middle_phase %= priv->num_phases;
>  	dev_info(host->dev, "Successfully tuned phase to %d\n",
> -		 TUNING_ITERATION_TO_PHASE(middle_phase));
> +		 TUNING_ITERATION_TO_PHASE(middle_phase, priv->num_phases));
>  
>  	clk_set_phase(priv->sample_clk,
> -		      TUNING_ITERATION_TO_PHASE(middle_phase));
> +		      TUNING_ITERATION_TO_PHASE(middle_phase,
> +						priv->num_phases));
>  
>  free:
>  	kfree(ranges);
> @@ -264,6 +272,10 @@ static int dw_mci_rk3288_parse_dt(struct dw_mci *host)
>  	if (!priv)
>  		return -ENOMEM;
>  
> +	if (of_property_read_u32(np, "rockchip,desired-num-phases",
> +					&priv->num_phases))
> +		priv->num_phases = 360;
> +
>  	if (of_property_read_u32(np, "rockchip,default-sample-phase",
>  					&priv->default_sample_phase))
>  		priv->default_sample_phase = 0;
>