[PATCH v5 04/17] arm: mach-k3: Add basic support for J784S4 SoC definition

[Bryan Brattlof]

Hi Apurva!

On November 30, 2023 thus sayeth Apurva Nandan:
> Add J784S4 initialization files for initial SPL boot.
> 
> Signed-off-by: Hari Nagalla <hnagalla at ti.com>
> [ add firewall configurations and change the R5 MCU scratchpad ]
> Signed-off-by: Manorit Chawdhry <m-chawdhry at ti.com>
> Signed-off-by: Dasnavis Sabiya <sabiya.d at ti.com>
> Signed-off-by: Apurva Nandan <a-nandan at ti.com>
> ---
>  arch/arm/mach-k3/Kconfig                      |  16 +-
>  arch/arm/mach-k3/Makefile                     |   2 +
>  arch/arm/mach-k3/arm64-mmu.c                  |  52 +++
>  arch/arm/mach-k3/include/mach/hardware.h      |   4 +
>  .../mach-k3/include/mach/j784s4_hardware.h    |  60 ++++
>  arch/arm/mach-k3/include/mach/j784s4_spl.h    |  47 +++
>  arch/arm/mach-k3/include/mach/spl.h           |   4 +
>  arch/arm/mach-k3/j784s4_fdt.c                 |  15 +
>  arch/arm/mach-k3/j784s4_init.c                | 338 ++++++++++++++++++
>  arch/arm/mach-k3/r5/Makefile                  |   1 +
>  10 files changed, 532 insertions(+), 7 deletions(-)
>  create mode 100644 arch/arm/mach-k3/include/mach/j784s4_hardware.h
>  create mode 100644 arch/arm/mach-k3/include/mach/j784s4_spl.h
>  create mode 100644 arch/arm/mach-k3/j784s4_fdt.c
>  create mode 100644 arch/arm/mach-k3/j784s4_init.c
> 

...

> +	if (IS_ENABLED(CONFIG_TARGET_J784S4_R5_EVM)) {
> +		ret = uclass_get_device_by_name(UCLASS_MISC, "msmc", &dev);
> +		if (ret)
> +			panic("Probe of msmc failed: %d\n", ret);
> +
> +		ret = uclass_get_device(UCLASS_RAM, 0, &dev);
> +		if (ret)
> +			panic("DRAM 0 init failed: %d\n", ret);
> +
> +		ret = uclass_next_device_err(&dev);
> +		if (ret)
> +			panic("DRAM 1 init failed: %d\n", ret);
> +
> +		ret = uclass_next_device_err(&dev);
> +		if (ret)
> +			panic("DRAM 2 init failed: %d\n", ret);
> +
> +		ret = uclass_next_device_err(&dev);
> +		if (ret)
> +			panic("DRAM 3 init failed: %d\n", ret);
> +	}

I don't know if this is is the right approach. I can see situations 
where people will not have all these controllers utilized or would want 
to artificially remove them for some reason. 

All of that to say I don't thing we can rely on there being 4 UCLASS_RAM 
devices present at all times in the device tree.

~Bryan