Re: [PATCH v7 09/26] PM / devfreq: rockchip-dfi: Clean up DDR type register defines

From: Chanwoo Choi
Date: Fri Oct 06 2023 - 15:11:38 EST


On 23. 7. 4. 18:32, Sascha Hauer wrote:
> Use the HIWORD_UPDATE() define known from other rockchip drivers to
> make the defines look less odd to the readers who've seen other
> rockchip drivers.
>
> The HIWORD registers have their functional bits in the lower 16 bits
> whereas the upper 16 bits contain a mask. Only the functional bits that
> have the corresponding mask bit set are modified during a write. Although
> the register writes look different, the end result should be the same,
> at least there's no functional change intended with this patch.
>
> Reviewed-by: Sebastian Reichel <sebastian.reichel@xxxxxxxxxxxxx>
> Signed-off-by: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
> ---
> drivers/devfreq/event/rockchip-dfi.c | 33 ++++++++++++++++++----------
> 1 file changed, 21 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/devfreq/event/rockchip-dfi.c b/drivers/devfreq/event/rockchip-dfi.c
> index 6bccb6fbcfc0c..6b3ef97b3be09 100644
> --- a/drivers/devfreq/event/rockchip-dfi.c
> +++ b/drivers/devfreq/event/rockchip-dfi.c
> @@ -26,15 +26,19 @@
>
> #define DMC_MAX_CHANNELS 2
>
> +#define HIWORD_UPDATE(val, mask) ((val) | (mask) << 16)
> +
> /* DDRMON_CTRL */
> #define DDRMON_CTRL 0x04
> -#define CLR_DDRMON_CTRL (0x1f0000 << 0)
> -#define LPDDR4_EN (0x10001 << 4)
> -#define HARDWARE_EN (0x10001 << 3)
> -#define LPDDR3_EN (0x10001 << 2)
> -#define SOFTWARE_EN (0x10001 << 1)
> -#define SOFTWARE_DIS (0x10000 << 1)
> -#define TIME_CNT_EN (0x10001 << 0)
> +#define DDRMON_CTRL_DDR4 BIT(5)
> +#define DDRMON_CTRL_LPDDR4 BIT(4)
> +#define DDRMON_CTRL_HARDWARE_EN BIT(3)
> +#define DDRMON_CTRL_LPDDR23 BIT(2)
> +#define DDRMON_CTRL_SOFTWARE_EN BIT(1)
> +#define DDRMON_CTRL_TIMER_CNT_EN BIT(0)
> +#define DDRMON_CTRL_DDR_TYPE_MASK (DDRMON_CTRL_DDR4 | \
> + DDRMON_CTRL_LPDDR4 | \
> + DDRMON_CTRL_LPDDR23)
>
> #define DDRMON_CH0_COUNT_NUM 0x28
> #define DDRMON_CH0_DFI_ACCESS_NUM 0x2c
> @@ -73,16 +77,20 @@ static void rockchip_dfi_start_hardware_counter(struct devfreq_event_dev *edev)
> void __iomem *dfi_regs = dfi->regs;
>
> /* clear DDRMON_CTRL setting */
> - writel_relaxed(CLR_DDRMON_CTRL, dfi_regs + DDRMON_CTRL);
> + writel_relaxed(HIWORD_UPDATE(0, DDRMON_CTRL_TIMER_CNT_EN | DDRMON_CTRL_SOFTWARE_EN |
> + DDRMON_CTRL_HARDWARE_EN), dfi_regs + DDRMON_CTRL);

You mentioned that there are no behavior changes even if the different value is written.
But, it looks strange. Could you please explain more detailed about it?


CLR_DDRMON_CTRL is 0x1f0000
vs.
HIWORD_UPDATE(0, DDRMON_CTRL_TIMER_CNT_EN | DDRMON_CTRL_SOFTWARE_EN | DDRMON_CTRL_HARDWARE_EN) = (0 | (BIT(0)|BIT(1)|BIT(3))<<16) = 0xb0000

>
> /* set ddr type to dfi */
> if (dfi->ddr_type == ROCKCHIP_DDRTYPE_LPDDR3)
> - writel_relaxed(LPDDR3_EN, dfi_regs + DDRMON_CTRL);
> + writel_relaxed(HIWORD_UPDATE(DDRMON_CTRL_LPDDR23, DDRMON_CTRL_DDR_TYPE_MASK),
> + dfi_regs + DDRMON_CTRL);

LPDDR3_EN (0x10001 << 2) = 0x40004
vs.
HIWORD_UPDATE(DDRMON_CTRL_LPDDR23, DDRMON_CTRL_DDR_TYPE_MASK) = (BIT(2) | (BIT(5)|BIT(4)|BIT(2))<<16) = 0x340004


> else if (dfi->ddr_type == ROCKCHIP_DDRTYPE_LPDDR4)
> - writel_relaxed(LPDDR4_EN, dfi_regs + DDRMON_CTRL);
> + writel_relaxed(HIWORD_UPDATE(DDRMON_CTRL_LPDDR4, DDRMON_CTRL_DDR_TYPE_MASK),
> + dfi_regs + DDRMON_CTRL);
>
> /* enable count, use software mode */
> - writel_relaxed(SOFTWARE_EN, dfi_regs + DDRMON_CTRL);
> + writel_relaxed(HIWORD_UPDATE(DDRMON_CTRL_SOFTWARE_EN, DDRMON_CTRL_SOFTWARE_EN),
> + dfi_regs + DDRMON_CTRL);
> }
>
> static void rockchip_dfi_stop_hardware_counter(struct devfreq_event_dev *edev)
> @@ -90,7 +98,8 @@ static void rockchip_dfi_stop_hardware_counter(struct devfreq_event_dev *edev)
> struct rockchip_dfi *dfi = devfreq_event_get_drvdata(edev);
> void __iomem *dfi_regs = dfi->regs;
>
> - writel_relaxed(SOFTWARE_DIS, dfi_regs + DDRMON_CTRL);
> + writel_relaxed(HIWORD_UPDATE(0, DDRMON_CTRL_SOFTWARE_EN),
> + dfi_regs + DDRMON_CTRL);
> }
>
> static void rockchip_dfi_read_counters(struct devfreq_event_dev *edev, struct dmc_count *count)

--
Best Regards,
Samsung Electronics
Chanwoo Choi