linux-kernel - Re: [PATCH v7 07/26] PM / devfreq: rockchip-dfi: introduce channel mask

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Message-ID: <859b0091-e361-6060-2977-4aba13af418a@kernel.org>
Date:   Sat, 7 Oct 2023 02:21:10 +0900
From:   Chanwoo Choi <chanwoo@...nel.org>
To:     Sascha Hauer <s.hauer@...gutronix.de>,
        linux-rockchip@...ts.infradead.org
Cc:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-pm@...r.kernel.org, Heiko Stuebner <heiko@...ech.de>,
        Kyungmin Park <kyungmin.park@...sung.com>,
        MyungJoo Ham <myungjoo.ham@...sung.com>,
        Will Deacon <will@...nel.org>,
        Mark Rutland <mark.rutland@....com>, kernel@...gutronix.de,
        Michael Riesch <michael.riesch@...fvision.net>,
        Robin Murphy <robin.murphy@....com>,
        Vincent Legoll <vincent.legoll@...il.com>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Conor Dooley <conor+dt@...nel.org>, devicetree@...r.kernel.org,
        Sebastian Reichel <sebastian.reichel@...labora.com>
Subject: Re: [PATCH v7 07/26] PM / devfreq: rockchip-dfi: introduce channel
 mask

Hi,

On 23. 7. 4. 18:32, Sascha Hauer wrote:
> Different Rockchip SoC variants have a different number of channels.
> Introduce a channel mask to make the number of channels configurable
> from SoC initialization code.
> 
> Reviewed-by: Sebastian Reichel <sebastian.reichel@...labora.com>
> Signed-off-by: Sascha Hauer <s.hauer@...gutronix.de>
> ---
>  drivers/devfreq/event/rockchip-dfi.c | 23 +++++++++++++++++------
>  1 file changed, 17 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/devfreq/event/rockchip-dfi.c b/drivers/devfreq/event/rockchip-dfi.c
> index 126bb744645b6..82de24a027579 100644
> --- a/drivers/devfreq/event/rockchip-dfi.c
> +++ b/drivers/devfreq/event/rockchip-dfi.c
> @@ -18,10 +18,11 @@
>  #include <linux/list.h>
>  #include <linux/of.h>
>  #include <linux/of_device.h>
> +#include <linux/bits.h>
>  
>  #include <soc/rockchip/rk3399_grf.h>
>  
> -#define RK3399_DMC_NUM_CH	2
> +#define DMC_MAX_CHANNELS	2
>  
>  /* DDRMON_CTRL */
>  #define DDRMON_CTRL	0x04
> @@ -44,7 +45,7 @@ struct dmc_count_channel {
>  };
>  
>  struct dmc_count {
> -	struct dmc_count_channel c[RK3399_DMC_NUM_CH];
> +	struct dmc_count_channel c[DMC_MAX_CHANNELS];
>  };
>  
>  /*
> @@ -61,6 +62,7 @@ struct rockchip_dfi {
>  	struct regmap *regmap_pmu;
>  	struct clk *clk;
>  	u32 ddr_type;
> +	unsigned int channel_mask;
>  };
>  
>  static void rockchip_dfi_start_hardware_counter(struct devfreq_event_dev *edev)
> @@ -95,7 +97,9 @@ static void rockchip_dfi_read_counters(struct devfreq_event_dev *edev, struct dm
>  	u32 i;
>  	void __iomem *dfi_regs = dfi->regs;
>  
> -	for (i = 0; i < RK3399_DMC_NUM_CH; i++) {
> +	for (i = 0; i < DMC_MAX_CHANNELS; i++) {
> +		if (!(dfi->channel_mask & BIT(i)))
> +			continue;
>  		count->c[i].access = readl_relaxed(dfi_regs +
>  				DDRMON_CH0_DFI_ACCESS_NUM + i * 20);
>  		count->c[i].total = readl_relaxed(dfi_regs +
> @@ -145,9 +149,14 @@ static int rockchip_dfi_get_event(struct devfreq_event_dev *edev,
>  	rockchip_dfi_read_counters(edev, &count);
>  
>  	/* We can only report one channel, so find the busiest one */
> -	for (i = 0; i < RK3399_DMC_NUM_CH; i++) {
> -		u32 a = count.c[i].access - last->c[i].access;
> -		u32 t = count.c[i].total - last->c[i].total;
> +	for (i = 0; i < DMC_MAX_CHANNELS; i++) {

Instead of DMC_MAX_CHANNELS defintion,
you can initialize the max channel in each rkXXXX_dfi_init() like 'dfi->channel_count'.
It reduces the unnecessary loop by initializing the proper max channel.

> +		u32 a, t;
> +
> +		if (!(dfi->channel_mask & BIT(i)))
> +			continue;
> +
> +		a = count.c[i].access - last->c[i].access;
> +		t = count.c[i].total - last->c[i].total;
>  
>  		if (a > access) {
>  			access = a;
> @@ -185,6 +194,8 @@ static int rk3399_dfi_init(struct rockchip_dfi *dfi)
>  	dfi->ddr_type = (val >> RK3399_PMUGRF_DDRTYPE_SHIFT) &
>  			RK3399_PMUGRF_DDRTYPE_MASK;
>  
> +	dfi->channel_mask = GENMASK(1, 0);
> +
>  	return 0;
>  };
>  

-- 
Best Regards,
Samsung Electronics
Chanwoo Choi