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Date:   Mon, 9 Oct 2023 07:19:04 +0900
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Subject: Re: [PATCH v7 18/26] PM / devfreq: rockchip-dfi: account for multiple
 DDRMON_CTRL registers
Content-Language: en-US
To:     Sascha Hauer <s.hauer@pengutronix.de>,
        linux-rockchip@lists.infradead.org
Cc:     linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-pm@vger.kernel.org, Heiko Stuebner <heiko@sntech.de>,
        Kyungmin Park <kyungmin.park@samsung.com>,
        MyungJoo Ham <myungjoo.ham@samsung.com>,
        Will Deacon <will@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>, kernel@pengutronix.de,
        Michael Riesch <michael.riesch@wolfvision.net>,
        Robin Murphy <robin.murphy@arm.com>,
        Vincent Legoll <vincent.legoll@gmail.com>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Conor Dooley <conor+dt@kernel.org>, devicetree@vger.kernel.org,
        Sebastian Reichel <sebastian.reichel@collabora.com>,
        Jonathan Cameron <Jonathan.Cameron@huawei.com>
References: <20230704093242.583575-1-s.hauer@pengutronix.de>
 <20230704093242.583575-19-s.hauer@pengutronix.de>
From:   Chanwoo Choi <chanwoo@kernel.org>
In-Reply-To: <20230704093242.583575-19-s.hauer@pengutronix.de>
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Precedence: bulk

On 23. 7. 4. 18:32, Sascha Hauer 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.
> 
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.com>
> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
> ---
>  drivers/devfreq/event/rockchip-dfi.c | 72 ++++++++++++++++++----------
>  1 file changed, 48 insertions(+), 24 deletions(-)
> 
> diff --git a/drivers/devfreq/event/rockchip-dfi.c b/drivers/devfreq/event/rockchip-dfi.c
> index 85ec93fd41858..2362d3953ba40 100644
> --- a/drivers/devfreq/event/rockchip-dfi.c
> +++ b/drivers/devfreq/event/rockchip-dfi.c
> @@ -113,12 +113,13 @@ 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);
>  
> @@ -132,29 +133,41 @@ static int rockchip_dfi_enable(struct rockchip_dfi *dfi)
>  		goto out;
>  	}
>  
> -	/* clear DDRMON_CTRL setting */
> -	writel_relaxed(HIWORD_UPDATE(0, DDRMON_CTRL_TIMER_CNT_EN | DDRMON_CTRL_SOFTWARE_EN |
> -		       DDRMON_CTRL_HARDWARE_EN), dfi_regs + DDRMON_CTRL);
> +	for (i = 0; i < DMC_MAX_CHANNELS; i++) {
> +		u32 ctrl = 0;
>  
> -	/* 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;
> -	}
> +		if (!(dfi->channel_mask & BIT(i)))
> +			continue;
>  
> -	/* enable count, use software mode */
> -	writel_relaxed(HIWORD_UPDATE(DDRMON_CTRL_SOFTWARE_EN, DDRMON_CTRL_SOFTWARE_EN),
> -		       dfi_regs + DDRMON_CTRL);
> +		/* clear DDRMON_CTRL setting */
> +		writel_relaxed(HIWORD_UPDATE(0, DDRMON_CTRL_TIMER_CNT_EN |
> +			       DDRMON_CTRL_SOFTWARE_EN | DDRMON_CTRL_HARDWARE_EN),
> +			       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:
> +			ctrl = DDRMON_CTRL_LPDDR23;
> +			break;
> +		case ROCKCHIP_DDRTYPE_LPDDR4:
> +		case ROCKCHIP_DDRTYPE_LPDDR4X:
> +			ctrl = DDRMON_CTRL_LPDDR4;
> +			break;
> +		default:
> +			break;
> +		}
> +
> +		writel_relaxed(HIWORD_UPDATE(ctrl, DDRMON_CTRL_DDR_TYPE_MASK),
> +			       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 + i * dfi->ddrmon_stride + DDRMON_CTRL);
> +
> +		if (dfi->ddrmon_ctrl_single)
> +			break;
> +	}
>  out:
>  	mutex_unlock(&dfi->mutex);
>  
> @@ -164,6 +177,7 @@ 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);
>  
> @@ -174,8 +188,17 @@ 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);
> @@ -666,6 +689,7 @@ 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;
>  };

Even if rk3568 has the only one channle and don't need to check whether 'dfi->ddrmon_ctrl_single'
is true or not because of 'if (!(dfi->channel_mask & BIT(i)))',
I recommand the add 'dfi->ddrmon_ctrl_single = true;' for rk3568 in order to
provide the number of DDRMON_CTRL reigster of rk3568.

If rk3568 doesn't have the 'ddrmon_ctrl_single', actually it is not easy
to catch what why are there no initilization for rk3568. 
 
-- 
Best Regards,
Samsung Electronics
Chanwoo Choi