[PATCH] MIPS: ralink: mt7621: add memory detection support

[Ilya Lipnitskiy]

On Thu, Mar 25, 2021 at 3:01 AM Thomas Bogendoerfer
<tsbogend at alpha.franken.de> wrote:
>
> On Tue, Mar 16, 2021 at 10:59:02PM -0700, Ilya Lipnitskiy wrote:
> > From: Chuanhong Guo <gch981213 at gmail.com>
> >
> > mt7621 has the following memory map:
> > 0x0-0x1c000000: lower 448m memory
> > 0x1c000000-0x2000000: peripheral registers
> > 0x20000000-0x2400000: higher 64m memory
> >
> > detect_memory_region in arch/mips/kernel/setup.c only adds the first
> > memory region and isn't suitable for 512m memory detection because
> > it may accidentally read the memory area for peripheral registers.
> >
> > This commit adds memory detection capability for mt7621:
> >   1. Add the highmem area when 512m is detected.
> >   2. Guard memcmp from accessing peripheral registers:
> >      This only happens when a user decided to change kernel load address
> >      to 256m or higher address. Since this is a quite unusual case, we
> >      just skip 512m testing and return 256m as memory size.
> >
> > [...]
>
> I get
>
> WARNING: modpost: vmlinux.o(.text+0x132c): Section mismatch in reference from the function prom_soc_init() to the function .init.text:mt7621_memory_detect()
> The function prom_soc_init() references
> the function __init mt7621_memory_detect().
> This is often because prom_soc_init lacks a __init
> annotation or the annotation of mt7621_memory_detect is wrong.
>
> Can you please fix this ?
Thanks, I will fix it. Having trouble reproducing the error, but I
clearly see the issue. Are you building on a MIPS target or
cross-compiling (I'm cross-compiling and no errors).

Ilya