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From:   "Chanwoo Choi" <cw00.choi@samsung.com>
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>,
        "'Chanwoo Choi'" <chanwoo@kernel.org>,
        "'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>
In-Reply-To: <20231018061714.3553817-15-s.hauer@pengutronix.de>
Subject: RE: [PATCH v8 14/26] PM / devfreq: rockchip-dfi: Prepare for
 multiple users
Date:   Thu, 19 Oct 2023 20:58:27 +0900
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> -----Original Message-----
> From: Sascha Hauer <s.hauer@pengutronix.de>
> Sent: Wednesday, October 18, 2023 3:17 PM
> To: 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>; Chanwoo Choi
> <chanwoo@kernel.org>; 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>; Sascha Hauer <s.hauer@pengutronix.de>;
> Jonathan Cameron <Jonathan.Cameron@huawei.com>; Chanwoo Choi
> <cw00.choi@samsung.com>
> Subject: [PATCH v8 14/26] PM / devfreq: rockchip-dfi: Prepare for multiple
> users
> 
> When adding perf support later the DFI must be enabled when either of
> devfreq-event or perf is active. Prepare for that by adding a usage
> counter for the DFI. Also move enabling and disabling of the clock away
> from the devfreq-event specific functions to which the perf specific part
> won't have access.
> 
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.com>
> Acked-by: Chanwoo Choi <cw00.choi@samsung.com>
> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
> ---
>  drivers/devfreq/event/rockchip-dfi.c | 57 +++++++++++++++++++---------
>  1 file changed, 40 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/devfreq/event/rockchip-dfi.c
> b/drivers/devfreq/event/rockchip-dfi.c
> index d56a33d03db4c..7a4f1901314d4 100644
> --- a/drivers/devfreq/event/rockchip-dfi.c
> +++ b/drivers/devfreq/event/rockchip-dfi.c
> @@ -68,14 +68,29 @@ struct rockchip_dfi {
>  	void __iomem *regs;
>  	struct regmap *regmap_pmu;
>  	struct clk *clk;
> +	int usecount;
> +	struct mutex mutex;
>  	u32 ddr_type;
>  	unsigned int channel_mask;
>  	unsigned int max_channels;
>  };
> 
> -static void rockchip_dfi_start_hardware_counter(struct rockchip_dfi *dfi)
> +static int rockchip_dfi_enable(struct rockchip_dfi *dfi)
>  {
>  	void __iomem *dfi_regs = dfi->regs;
> +	int ret = 0;
> +
> +	mutex_lock(&dfi->mutex);
> +
> +	dfi->usecount++;
> +	if (dfi->usecount > 1)
> +		goto out;
> +
> +	ret = clk_prepare_enable(dfi->clk);
> +	if (ret) {
> +		dev_err(&dfi->edev->dev, "failed to enable dfi clk: %d\n",
> ret);
> +		goto out;
> +	}
> 
>  	/* clear DDRMON_CTRL setting */
>  	writel_relaxed(HIWORD_UPDATE(0, DDRMON_CTRL_TIMER_CNT_EN |
> DDRMON_CTRL_SOFTWARE_EN | @@ -100,14 +115,30 @@ static void
> rockchip_dfi_start_hardware_counter(struct rockchip_dfi *dfi)
>  	/* enable count, use software mode */
>  	writel_relaxed(HIWORD_UPDATE(DDRMON_CTRL_SOFTWARE_EN,
> DDRMON_CTRL_SOFTWARE_EN),
>  		       dfi_regs + DDRMON_CTRL);
> +out:
> +	mutex_unlock(&dfi->mutex);
> +
> +	return ret;
>  }
> 
> -static void rockchip_dfi_stop_hardware_counter(struct rockchip_dfi *dfi)
> +static void rockchip_dfi_disable(struct rockchip_dfi *dfi)
>  {
>  	void __iomem *dfi_regs = dfi->regs;
> 
> +	mutex_lock(&dfi->mutex);
> +
> +	dfi->usecount--;
> +
> +	WARN_ON_ONCE(dfi->usecount < 0);
> +
> +	if (dfi->usecount > 0)
> +		goto out;
> +
>  	writel_relaxed(HIWORD_UPDATE(0, DDRMON_CTRL_SOFTWARE_EN),
>  		       dfi_regs + DDRMON_CTRL);
> +	clk_disable_unprepare(dfi->clk);
> +out:
> +	mutex_unlock(&dfi->mutex);
>  }
> 
>  static void rockchip_dfi_read_counters(struct rockchip_dfi *dfi, struct
> dmc_count *count) @@ -125,29 +156,20 @@ static void
> rockchip_dfi_read_counters(struct rockchip_dfi *dfi, struct dmc_coun
>  	}
>  }
> 
> -static int rockchip_dfi_disable(struct devfreq_event_dev *edev)
> +static int rockchip_dfi_event_disable(struct devfreq_event_dev *edev)
>  {
>  	struct rockchip_dfi *dfi = devfreq_event_get_drvdata(edev);
> 
> -	rockchip_dfi_stop_hardware_counter(dfi);
> -	clk_disable_unprepare(dfi->clk);
> +	rockchip_dfi_disable(dfi);
> 
>  	return 0;
>  }
> 
> -static int rockchip_dfi_enable(struct devfreq_event_dev *edev)
> +static int rockchip_dfi_event_enable(struct devfreq_event_dev *edev)
>  {
>  	struct rockchip_dfi *dfi = devfreq_event_get_drvdata(edev);
> -	int ret;
> -
> -	ret = clk_prepare_enable(dfi->clk);
> -	if (ret) {
> -		dev_err(&edev->dev, "failed to enable dfi clk: %d\n", ret);
> -		return ret;
> -	}
> 
> -	rockchip_dfi_start_hardware_counter(dfi);
> -	return 0;
> +	return rockchip_dfi_enable(dfi);
>  }
> 
>  static int rockchip_dfi_set_event(struct devfreq_event_dev *edev) @@ -
> 191,8 +213,8 @@ static int rockchip_dfi_get_event(struct devfreq_event_dev
> *edev,  }
> 
>  static const struct devfreq_event_ops rockchip_dfi_ops = {
> -	.disable = rockchip_dfi_disable,
> -	.enable = rockchip_dfi_enable,
> +	.disable = rockchip_dfi_event_disable,
> +	.enable = rockchip_dfi_event_enable,
>  	.get_event = rockchip_dfi_get_event,
>  	.set_event = rockchip_dfi_set_event,
>  };
> @@ -280,6 +302,7 @@ static int rockchip_dfi_probe(struct platform_device
> *pdev)
>  		return PTR_ERR(dfi->regmap_pmu);
> 
>  	dfi->dev = dev;
> +	mutex_init(&dfi->mutex);
> 
>  	desc = &dfi->desc;
>  	desc->ops = &rockchip_dfi_ops;
> --
> 2.39.2


Applied it. Thanks

Best Regards,
Chanwoo Choi