[PATCH v2 0/2] ARM: shmobile: kzm9g: Declare the full 512 MiB of RAM
Simon Horman
horms at verge.net.au
Wed Jan 7 16:14:12 PST 2015
On Tue, Jan 06, 2015 at 08:17:37PM +0100, Geert Uytterhoeven wrote:
> Hi Simon, Magnus,
>
> This patch series prepares kzm9g and kzm9g-reference dts for booting a
> multi-platform kernel.
>
> Traditionally, the first 16 MiB of RAM was reserved for the RT
> processor. However, this is incompatible with CONFIG_AUTO_ZRELADDR=y,
> which requires that the start address of physical memory is a multiple
> of 128 MiB.
>
> As CONFIG_AUTO_ZRELADDR=y is enabled for multi-platform kernels, declare
> RAM to start at 0x40000000.
>
> While at it, reclaim the last 8 MiB of RAM, too, so the full 512 MiB is
> available. We don't know the exact reason why the last 8 MiB of RAM
> was reserved, but thanks to Simon we know it is not used for a U-Boot
> splash screen. Note that kzm9g_defconfig still has
> CONFIG_MEMORY_START=0x41000000 and CONFIG_MEMORY_SIZE=0x1f000000, so
> before the advent of DT we scribbled over the last 8 MiB, too.
>
> This is an alternative solution for "[PATCH v2 01/05] ARM: shmobile:
> kzm9g-reference: 0x48008000 load address"
> (http://www.spinics.net/lists/linux-sh/msg38385.html), which
> (a) doesn't loose 112 MiB of RAM, and
> (b) doesn't force to switch from zImage to uImage.
>
> Thanks for applying!
Thanks, done.
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