[PATCH 3/3] arm: mach-k3: am62p: Fixup a53 max cpu frequency by speed-grade

[Bryan Brattlof]

Hi Aparna!

On December 18, 2024 thus sayeth Aparna Patra:
> AM62P SoC has multiple speed grades. Add function to delete
> non-relevant CPU frequency nodes, based on the information
> retrieved from hardware registers. Fastest grade's maximum
> frequency also depends on PMIC voltage, hence to simplify
> implementation use the smaller value.
> 

The R5 SPL will start the A53 at whatever frequency we have specified in 
the R5 DTB. We'll need to also update that before we start that core.

> Signed-off-by: Aparna Patra <a-patra at ti.com>
> ---
>  arch/arm/mach-k3/am62px/am62p5_fdt.c          | 12 ++++++++++++
>  .../arm/mach-k3/include/mach/am62p_hardware.h | 19 +++++++++++++++++++
>  2 files changed, 31 insertions(+)
> 
> diff --git a/arch/arm/mach-k3/am62px/am62p5_fdt.c b/arch/arm/mach-k3/am62px/am62p5_fdt.c
> index 96194cebcd..2c40fa5a59 100644
> --- a/arch/arm/mach-k3/am62px/am62p5_fdt.c
> +++ b/arch/arm/mach-k3/am62px/am62p5_fdt.c
> @@ -74,12 +74,24 @@ static void fdt_fixup_thermal_zone_nodes_am62p(void *blob, int maxc)
>  	}
>  }
>  
> +static void fdt_fixup_cpu_freq_nodes_am62p(void *blob, int max_freq)
> +{
> +	if (max_freq >= 1250000000)
> +		return;
> +

With parts that only support 1.25GHz (18 or R) we'll need to disable the 
1.4GHz OPP.

> +	if (max_freq <= 1000000000) {
> +		fdt_del_node_path(blob, "/opp-table/opp-1250000000");
> +		fdt_del_node_path(blob, "/opp-table/opp-1400000000");
> +	}
> +}
> +
>  int ft_system_setup(void *blob, struct bd_info *bd)
>  {
>  	fdt_fixup_cores_wdt_nodes_am62p(blob, k3_get_core_nr());
>  	fdt_fixup_video_codec_nodes_am62p(blob, k3_has_video_codec());
>  	fdt_fixup_canfd_nodes_am62p(blob, k3_has_canfd());
>  	fdt_fixup_thermal_zone_nodes_am62p(blob, k3_get_max_temp());
> +	fdt_fixup_cpu_freq_nodes_am62p(blob, k3_get_a53_max_frequency());
>  	fdt_fixup_reserved(blob, "tfa", CONFIG_K3_ATF_LOAD_ADDR, 0x80000);
>  	fdt_fixup_reserved(blob, "optee", CONFIG_K3_OPTEE_LOAD_ADDR, 0x1800000);
>  
> diff --git a/arch/arm/mach-k3/include/mach/am62p_hardware.h b/arch/arm/mach-k3/include/mach/am62p_hardware.h
> index 2f1c8517e6..95af5c5c54 100644
> --- a/arch/arm/mach-k3/include/mach/am62p_hardware.h
> +++ b/arch/arm/mach-k3/include/mach/am62p_hardware.h
> @@ -26,6 +26,8 @@
>  #define JTAG_DEV_CANFD_SHIFT			15
>  #define JTAG_DEV_VIDEO_CODEC_MASK			BIT(14)
>  #define JTAG_DEV_VIDEO_CODEC_SHIFT			14
> +#define JTAG_DEV_SPEED_MASK			GENMASK(10, 6)
> +#define JTAG_DEV_SPEED_SHIFT			6
>  #define JTAG_DEV_TEMP_MASK			GENMASK(5, 3)
>  #define JTAG_DEV_TEMP_SHIFT			3
>  
> @@ -118,6 +120,23 @@ static inline int k3_get_max_temp(void)
>  		return JTAG_DEV_TEMP_EXTENDED_VALUE;
>  }
>  
> +static inline char k3_get_speed_grade(void)
> +{
> +	u32 dev_id = readl(CTRLMMR_WKUP_JTAG_DEVICE_ID);
> +	u32 speed_grade = (dev_id & JTAG_DEV_SPEED_MASK) >>
> +			   JTAG_DEV_SPEED_SHIFT;
> +
> +	return 'A' - 1 + speed_grade;
> +}
> +
> +static inline int k3_get_a53_max_frequency(void)
> +{
> +	if (k3_get_speed_grade() == 'O')
> +		return 1000000000;
> +	else
> +		return 1250000000;
> +}
> +
>  #if defined(CONFIG_SYS_K3_SPL_ATF) && !defined(__ASSEMBLY__)
>  
>  static const u32 put_device_ids[] = {};
> -- 
> 2.34.1
>