[U-Boot] [PATCH] arm: mvebu: set 38x and 39x AVS on lower frequency

[Stefan Roese]

Hi Baruch,

On 24.06.19 10:29, Baruch Siach wrote:
> Reduce Auto Voltage Scaling VDD limit when core frequency is lower than
> 1600MHz. This reduces core voltage level from 1.25V to 1.15V, which
> saves power.
> 
> The code is taken from Marvell's U-Boot 2013.01 revision 18.06.
> 
> Signed-off-by: Baruch Siach <baruch at tkos.co.il>

This patch breaks (at least) some Armada XP based boards:

$ ./tools/buildman/buildman theadorable_debug
boards.cfg is up to date. Nothing to do.
Building current source for 1 boards (1 thread, 16 jobs per thread)
        arm:  +   theadorable_debug
+arch/arm/mach-mvebu/built-in.o: In function `board_init_f':
+arch/arm/mach-mvebu/spl.c:130: undefined reference to `mv_avs_init'
+make[2]: *** [scripts/Makefile.spl:404: spl/u-boot-spl] Error 1
+make[1]: *** [Makefile:1727: spl/u-boot-spl] Error 2
+make: *** [Makefile:148: sub-make] Error 2

Could you please check and fix this in v2? Please run a build test
at least for all MVEBU boards (buildman mvebu).

Thanks,
Stefan

> ---
>   arch/arm/mach-mvebu/include/mach/cpu.h        |  3 +++
>   arch/arm/mach-mvebu/serdes/a38x/sys_env_lib.c | 26 +++++++++++++++++++
>   arch/arm/mach-mvebu/serdes/a38x/sys_env_lib.h |  4 +++
>   arch/arm/mach-mvebu/spl.c                     |  3 +++
>   4 files changed, 36 insertions(+)
> 
> diff --git a/arch/arm/mach-mvebu/include/mach/cpu.h b/arch/arm/mach-mvebu/include/mach/cpu.h
> index e6140d67293e..e1128ee90f01 100644
> --- a/arch/arm/mach-mvebu/include/mach/cpu.h
> +++ b/arch/arm/mach-mvebu/include/mach/cpu.h
> @@ -163,6 +163,9 @@ int serdes_phy_config(void);
>    */
>   int ddr3_init(void);
>   
> +/* Auto Voltage Scaling */
> +void mv_avs_init(void);
> +
>   /*
>    * get_ref_clk
>    *
> diff --git a/arch/arm/mach-mvebu/serdes/a38x/sys_env_lib.c b/arch/arm/mach-mvebu/serdes/a38x/sys_env_lib.c
> index d387893af37d..e9dd096ad0f5 100644
> --- a/arch/arm/mach-mvebu/serdes/a38x/sys_env_lib.c
> +++ b/arch/arm/mach-mvebu/serdes/a38x/sys_env_lib.c
> @@ -256,3 +256,29 @@ u8 sys_env_device_rev_get(void)
>   	value = reg_read(DEV_VERSION_ID_REG);
>   	return (value & (REVISON_ID_MASK)) >> REVISON_ID_OFFS;
>   }
> +
> +void mv_avs_init(void)
> +{
> +	u32 sar_freq;
> +
> +	if (!(IS_ENABLED(CONFIG_ARMADA_38X) || IS_ENABLED(CONFIG_ARMADA_39X)))
> +		return;
> +
> +	reg_write(AVS_DEBUG_CNTR_REG, AVS_DEBUG_CNTR_DEFAULT_VALUE);
> +	reg_write(AVS_DEBUG_CNTR_REG, AVS_DEBUG_CNTR_DEFAULT_VALUE);
> +
> +	sar_freq = reg_read(DEVICE_SAMPLE_AT_RESET1_REG);
> +	sar_freq = sar_freq >> SAR_FREQ_OFFSET & SAR_FREQ_MASK;
> +
> +	/* Set AVS value only for core frequency of 1600MHz or less.
> +	 * For higher frequency leave the default value.
> +	 */
> +	if (sar_freq <= 0xd) {
> +		u32 avs_reg_data = reg_read(AVS_ENABLED_CONTROL);
> +
> +		avs_reg_data &= ~(AVS_LOW_VDD_LIMIT_MASK
> +				| AVS_HIGH_VDD_LIMIT_MASK);
> +		avs_reg_data |= AVS_LOW_VDD_SLOW_VAL | AVS_HIGH_VDD_SLOW_VAL;
> +		reg_write(AVS_ENABLED_CONTROL, avs_reg_data);
> +	}
> +}
> diff --git a/arch/arm/mach-mvebu/serdes/a38x/sys_env_lib.h b/arch/arm/mach-mvebu/serdes/a38x/sys_env_lib.h
> index 365332d2b048..1774a5b780ca 100644
> --- a/arch/arm/mach-mvebu/serdes/a38x/sys_env_lib.h
> +++ b/arch/arm/mach-mvebu/serdes/a38x/sys_env_lib.h
> @@ -33,6 +33,8 @@
>   #define DEV_ID_REG_DEVICE_ID_OFFS	16
>   #define DEV_ID_REG_DEVICE_ID_MASK	0xffff0000
>   
> +#define SAR_FREQ_OFFSET			10
> +#define SAR_FREQ_MASK			0x1f
>   #define SAR_DEV_ID_OFFS			27
>   #define SAR_DEV_ID_MASK			0x7
>   
> @@ -155,10 +157,12 @@
>   #define AVS_LOW_VDD_LIMIT_OFFS		4
>   #define AVS_LOW_VDD_LIMIT_MASK		(0xff << AVS_LOW_VDD_LIMIT_OFFS)
>   #define AVS_LOW_VDD_LIMIT_VAL		(0x27 << AVS_LOW_VDD_LIMIT_OFFS)
> +#define AVS_LOW_VDD_SLOW_VAL		(0x23 << AVS_LOW_VDD_LIMIT_OFFS)
>   
>   #define AVS_HIGH_VDD_LIMIT_OFFS		12
>   #define AVS_HIGH_VDD_LIMIT_MASK		(0xff << AVS_HIGH_VDD_LIMIT_OFFS)
>   #define AVS_HIGH_VDD_LIMIT_VAL		(0x27 << AVS_HIGH_VDD_LIMIT_OFFS)
> +#define AVS_HIGH_VDD_SLOW_VAL		(0x23 << AVS_HIGH_VDD_LIMIT_OFFS)
>   
>   /* Board ID numbers */
>   #define MARVELL_BOARD_ID_MASK		0x10
> diff --git a/arch/arm/mach-mvebu/spl.c b/arch/arm/mach-mvebu/spl.c
> index d54de5195624..3cb27b7f4b20 100644
> --- a/arch/arm/mach-mvebu/spl.c
> +++ b/arch/arm/mach-mvebu/spl.c
> @@ -126,6 +126,9 @@ void board_init_f(ulong dummy)
>   	ddr3_init();
>   #endif
>   
> +	/* Initialize Auto Voltage Scaling */
> +	mv_avs_init();
> +
>   	/*
>   	 * Return to the BootROM to continue the Marvell xmodem
>   	 * UART boot protocol. As initiated by the kwboot tool.
> 

Viele Grüße,
Stefan

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