[RFC][PATCH] rpi: Fix DRAM size reporting to show total RAM

Anders Roxell anders.roxell at linaro.org
Tue Nov 25 13:47:32 CET 2025


On Tue, 25 Nov 2025 at 13:20, Peter Robinson <pbrobinson at gmail.com> wrote:
>
> On Tue, 25 Nov 2025 at 10:25, Anders Roxell <anders.roxell at linaro.org> wrote:
> >
> > The VideoCore mailbox GET_ARM_MEMORY only reports the size of the
> > first accessible memory region (~947 MiB on RPi4 with 8GB), not the
> > total RAM. This causes U-Boot to display "DRAM: 947 MiB (total 7.9 GiB)"
> > instead of "DRAM: 7.9 GiB".
> >
> > On Raspberry Pi 4 with 8GB RAM, the memory is split across multiple
> > non-contiguous banks. The dram_init() function only sets gd->ram_size
> > to the first bank size reported by the VideoCore firmware, while
> > fdtdec_setup_memory_banksize() correctly populates all memory banks
> > from the device tree.
> >
> > Fix this by updating gd->ram_size after dram_init_banksize() has
> > populated all memory banks, so it reflects the actual total RAM
> > across all banks.
> >
> > Signed-off-by: Anders Roxell <anders.roxell at linaro.org>
>
> Please add details as to why this is RFC? What comments are you actually after?

I don't commit to u-boot that much, so I wasn't sure if this was the
right thing to do.

Cheers,
Anders


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