[PATCH] MIPS: ralink: mt7621: do memory detection on KSEG1

[Sergio Paracuellos]

Hi Guo,

On Fri, Feb 11, 2022 at 4:56 AM Chuanhong Guo <gch981213 at gmail.com> wrote:
>
> It's reported that current memory detection code occasionally detects
> larger memory under some bootloaders.
> Current memory detection code tests whether address space wraps around
> on KSEG0, which is unreliable because it's cached.
>
> Rewrite memory size detection to perform the same test on KSEG1 instead.
> While at it, this patch also does the following two things:
> 1. use a fixed pattern instead of a random function pointer as the magic
>    value.
> 2. add an additional memory write and a second comparison as part of the
>    test to prevent possible smaller memory detection result due to
>    leftover values in memory.
>
> Fixes: 139c949f7f0a MIPS: ("ralink: mt7621: add memory detection support")
> Reported-by: Rui Salvaterra <rsalvaterra at gmail.com>
> Signed-off-by: Chuanhong Guo <gch981213 at gmail.com>
> ---
>  arch/mips/ralink/mt7621.c | 36 +++++++++++++++++++++++-------------
>  1 file changed, 23 insertions(+), 13 deletions(-)

Thanks! Nothing seems to be broken after these changes, at least for
my boards :)

Tested-by: Sergio Paracuellos <sergio.paracuellos at gmail.com>

Best regards,
    Sergio Paracuellos