On Wed, 1 Apr 2026 at 18:40, Marek Vasut <[email protected]> wrote: > > On 4/1/26 5:29 PM, Ilias Apalodimas wrote: > > Hi Marek, > > > > On Wed, 1 Apr 2026 at 18:24, Marek Vasut <[email protected]> wrote: > >> > >> 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(). > > > > Yes, but when you calculate the reloc address and use a bigger > > ram_top, the right thing to do is adjust the size as well > > That is the root of my concern, ram_top and ram_size are always the > same, relocaddr is not.
Yes, relocaddr is basically ram_top. But I think we agree here. Changning ram_top without ram_size makes little sense. > > >> 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(). > > > > I really don't mind. I just don't see the point of making things so > > granular. Unless I am wrong and someone thinks it makes sense to > > change ram_top without taking into account the size. > Maybe it would make sense to decouple relocaddr from ram_top/ram_size > calculation ? Where? In setup_dest_addr()? Yea that can be moved out. But please have a look at the rest of the thread. TL;DR Staring at the code more we can make things a lot simpler. We can move dram_init_banksize() higher up in the INITCALL chain and calculate the size and ram_top from that. Then deciding where to relocate becomes trivial. The only problem is that the dram bank info is stored in bd, not gd (and bd is allocated later). I don't remember why that ended up in bd, but if can move that information in gd, the code will look a lot simpler. What I suggest is apply patches #1 & #2 now. I'll play around with the idea above tomorrow and if I hit a brick wall I can resend #3 & #4 separately.
