[U-Boot] [PATCH] lib: Add CONFIG_FDT_IGNORE_FIXUP_MEMORY_NODE

Wolfgang Denk wd at denx.de
Tue Apr 8 15:05:36 CEST 2014


Dear Nobuhiro,

In message <CABMQnV+k+Rmx7E8o-nfBpYg5-nWrXi6Oz_+BCYs-vDNdv_z-rw at mail.gmail.com> you wrote:
> 
> > Please explain why you would want to do this.  To me it makes no
> > sense.  Either U-Boot knows the correct memory size, then it should
> > pass it to Linux.  Or it does not, then U-Boot should be fixed.
> 
> For example, I can access the memory of all in the U-Boot, but I may
> want to control
> the highmem on Linux,I do not want to show a specific area from kernel
> and userland.

Is it not sufficient to pass some "mem=" boot argument?  We even have
automatic support for this in U-Boot (see the CONFIG_PRAM feature).

> > Also, I object that your implementation is ARM specific.  If such a
> > feature gets added, it should be architecture independent.
> 
> I see. But arch_fixup_memory_node() is used by ARM only.
> So, we see to be dependent on the ARM is only this.

All architectures that support the device tree update the memory size
for Linux, so we should find a generic way to handle this.  Actually
we should always strive to reduce this arhitecture specific code.

Best regards,

Wolfgang Denk

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