Subject: Re: [PATCH v4 07/21] PM / devfreq: rockchip-dfi: introduce channel mask

From: Jonathan Cameron <[email-masked]>
Date: Tue, 16 May 2023 16:50:09 +0100

On Fri,  5 May 2023 13:38:42 +0200
Sascha Hauer <[email-masked]> 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.

If it's just numbers, why not a count rather than a mask?

> 
> Signed-off-by: Sascha Hauer <[email-masked]>
> ---
>  drivers/devfreq/event/rockchip-dfi.c | 22 ++++++++++++++++------
>  1 file changed, 16 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/devfreq/event/rockchip-dfi.c b/drivers/devfreq/event/rockchip-dfi.c
> index 25d64d9166a9a..18d578730fd0c 100644
> --- a/drivers/devfreq/event/rockchip-dfi.c
> +++ b/drivers/devfreq/event/rockchip-dfi.c
> @@ -21,7 +21,7 @@
>  
>  #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 +44,7 @@ struct dmc_count_channel {
>  };
>  
>  struct dmc_count {
> -	struct dmc_count_channel c[RK3399_DMC_NUM_CH];
> +	struct dmc_count_channel c[DMC_MAX_CHANNELS];
>  };
>  
>  /*
> @@ -62,6 +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)
> @@ -96,7 +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 +
> @@ -146,9 +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++) {
> +		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;
> @@ -186,6 +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 = 3;

GENMASK(1, 0)

> +
>  	return 0;
>  };

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