Subject: Re: [PATCH v4 17/21] PM / devfreq: rockchip-dfi: account for multiple DDRMON_CTRL registers

From: Jonathan Cameron <[email-masked]>
Date: Wed, 17 May 2023 11:23:03 +0100

On Fri,  5 May 2023 13:38:52 +0200
Sascha Hauer <[email-masked]> wrote:

> The currently supported RK3399 has a set of registers per channel, but
> it has only a single DDRMON_CTRL register. With upcoming RK3588 this
> will be different, the RK3588 has a DDRMON_CTRL register per channel.
> 
> Instead of expecting a single DDRMON_CTRL register, loop over the
> channels and write the channel specific DDRMON_CTRL register. Break
> out early out of the loop when there is only a single DDRMON_CTRL
> register like on the RK3399.
> 
> Signed-off-by: Sascha Hauer <[email-masked]>
Trivial suggestion inline, but either way this looks fine to me.
Reviewed-by: Jonathan Cameron <[email-masked]>

> ---
>  drivers/devfreq/event/rockchip-dfi.c | 69 ++++++++++++++++++----------
>  1 file changed, 46 insertions(+), 23 deletions(-)
> 
> diff --git a/drivers/devfreq/event/rockchip-dfi.c b/drivers/devfreq/event/rockchip-dfi.c
> index 3d76e58c602b2..74d69153e6386 100644
> --- a/drivers/devfreq/event/rockchip-dfi.c
> +++ b/drivers/devfreq/event/rockchip-dfi.c
> @@ -101,12 +101,13 @@ struct rockchip_dfi {
>  	int burst_len;
>  	int buswidth[DMC_MAX_CHANNELS];
>  	int ddrmon_stride;
> +	bool ddrmon_ctrl_single;
>  };
>  
>  static int rockchip_dfi_enable(struct rockchip_dfi *dfi)
>  {
>  	void __iomem *dfi_regs = dfi->regs;
> -	int ret = 0;
> +	int i, ret = 0;
>  
>  	mutex_lock(&dfi->mutex);
>  
> @@ -120,28 +121,39 @@ static int rockchip_dfi_enable(struct rockchip_dfi *dfi)
>  		goto out;
>  	}
>  
> -	/* clear DDRMON_CTRL setting */
> -	writel_relaxed(HIWORD_UPDATE(0, 0xffff), dfi_regs + DDRMON_CTRL);
> +	for (i = 0; i < DMC_MAX_CHANNELS; i++) {
> +		if (!(dfi->channel_mask & BIT(i)))
> +			continue;
>  
> -	/* set ddr type to dfi */
> -	switch (dfi->ddr_type) {
> -	case ROCKCHIP_DDRTYPE_LPDDR2:
> -	case ROCKCHIP_DDRTYPE_LPDDR3:
> -		writel_relaxed(HIWORD_UPDATE(DDRMON_CTRL_LPDDR23, DDRMON_CTRL_DDR_TYPE_MASK),
> -			       dfi_regs + DDRMON_CTRL);
> -		break;
> -	case ROCKCHIP_DDRTYPE_LPDDR4:
> -	case ROCKCHIP_DDRTYPE_LPDDR4X:
> -		writel_relaxed(HIWORD_UPDATE(DDRMON_CTRL_LPDDR4, DDRMON_CTRL_DDR_TYPE_MASK),
> -			       dfi_regs + DDRMON_CTRL);
> -		break;
> -	default:
> -		break;
> -	}
> +		/* clear DDRMON_CTRL setting */

Indent is getting a bit deep. Perhaps it's better to factor out as a
*write_ddr_type() ?

> +		writel_relaxed(HIWORD_UPDATE(0, 0xffff),
> +			       dfi_regs + i * dfi->ddrmon_stride + DDRMON_CTRL);
> +
> +		/* set ddr type to dfi */
> +		switch (dfi->ddr_type) {
> +		case ROCKCHIP_DDRTYPE_LPDDR2:
> +		case ROCKCHIP_DDRTYPE_LPDDR3:
> +			writel_relaxed(HIWORD_UPDATE(DDRMON_CTRL_LPDDR23,
> +						     DDRMON_CTRL_DDR_TYPE_MASK),
> +				       dfi_regs + i * dfi->ddrmon_stride + DDRMON_CTRL);
> +			break;
> +		case ROCKCHIP_DDRTYPE_LPDDR4:
> +		case ROCKCHIP_DDRTYPE_LPDDR4X:
> +			writel_relaxed(HIWORD_UPDATE(DDRMON_CTRL_LPDDR4,
> +						     DDRMON_CTRL_DDR_TYPE_MASK),
> +				       dfi_regs + i * dfi->ddrmon_stride + DDRMON_CTRL);
> +			break;
> +		default:
> +			break;
> +		}
> +
> +		/* enable count, use software mode */
> +		writel_relaxed(HIWORD_UPDATE(DDRMON_CTRL_SOFTWARE_EN, DDRMON_CTRL_SOFTWARE_EN),
> +			       dfi_regs + i * dfi->ddrmon_stride + DDRMON_CTRL);
>  
> -	/* enable count, use software mode */
> -	writel_relaxed(HIWORD_UPDATE(DDRMON_CTRL_SOFTWARE_EN, DDRMON_CTRL_SOFTWARE_EN),
> -		       dfi_regs + DDRMON_CTRL);
> +		if (dfi->ddrmon_ctrl_single)
> +			break;
> +	}
>  out:
>  	mutex_unlock(&dfi->mutex);
>  
> @@ -151,6 +163,7 @@ static int rockchip_dfi_enable(struct rockchip_dfi *dfi)
>  static void rockchip_dfi_disable(struct rockchip_dfi *dfi)
>  {
>  	void __iomem *dfi_regs = dfi->regs;
> +	int i;
>  
>  	mutex_lock(&dfi->mutex);
>  
> @@ -161,8 +174,17 @@ static void rockchip_dfi_disable(struct rockchip_dfi *dfi)
>  	if (dfi->usecount > 0)
>  		goto out;
>  
> -	writel_relaxed(HIWORD_UPDATE(0, DDRMON_CTRL_SOFTWARE_EN),
> -		       dfi_regs + DDRMON_CTRL);
> +	for (i = 0; i < DMC_MAX_CHANNELS; i++) {
> +		if (!(dfi->channel_mask & BIT(i)))
> +			continue;
> +
> +		writel_relaxed(HIWORD_UPDATE(0, DDRMON_CTRL_SOFTWARE_EN),
> +			      dfi_regs + i * dfi->ddrmon_stride + DDRMON_CTRL);
> +
> +		if (dfi->ddrmon_ctrl_single)
> +			break;
> +	}
> +
>  	clk_disable_unprepare(dfi->clk);
>  out:
>  	mutex_unlock(&dfi->mutex);
> @@ -569,6 +591,7 @@ static int rk3399_dfi_init(struct rockchip_dfi *dfi)
>  	dfi->buswidth[1] = FIELD_GET(RK3399_PMUGRF_OS_REG2_BW_CH1, val) == 0 ? 4 : 2;
>  
>  	dfi->ddrmon_stride = 0x14;
> +	dfi->ddrmon_ctrl_single = true;
>  
>  	return 0;
>  };

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