[PATCH v2 3/4] fdtdec: Introduce fdtdec_setup_ram_size() to determine the memory size

[Marek Vasut]

On 4/1/26 8:43 AM, Ilias Apalodimas wrote:

>>> +++ b/include/fdtdec.h
>>> @@ -965,6 +965,21 @@ int fdtdec_setup_mem_ram_top(void);
>>>     * invalid
>>>     */
>>>    int fdtdec_setup_memory_banksize(void);
>>> +/**
>>> + * fdtdec_setup_ram_size() - decode and setup setup gd->ram_size to the sum of
>>> + *                        all banks
>>> + *
>>> + * Decode the /memory 'reg' property to determine the memory available in all
>>> + * banks and populate the global data ram_size with it.
>>> + *
>>> + * This function should be called from a boards board_get_usable_ram_top().
>>
>> Is the board_get_usable_ram_top() really the right place to call this ?
>> It feels like it is being conflated with ram_top here too.
> 
> I don't think so. You are effectively calculating the top address you
> should relocate to. You should also calculate the difference in
> ramsize. Those two should not be separated actions
The address where you relocate to is gd->relocaddr, which is ram_top 
minus all the reserved areas, see common/board_f.c setup_dest_addr().

This setup_dest_addr() function does manipulate with gd->ram_size , but 
only to handle CONFIG_SYS_MEM_TOP_HIDE , which may not be the right 
place for it, I think it would be better to have a separate initcall for 
the ram_size calculation, which precedes setup_dest_addr().

With that, the function description can claim that each function must be 
called before that specific initcall, fdtdec_setup_mem_ram_top() before 
setup_dest_addr() and fdtdec_setup_ram_size() before 
setup_whatever_is_the_new_initcall_name().