RE: [PATCH] PPC 85xx failure with odd memory sizes and CONFIG_HIGHMEM

From: Dale Farnsworth
=20
The CONFIG_FSL_BOOKE mmu setup code fails when CONFIG_HIGHMEM=3Dy
and the 3 fixed TLB entries cannot exactly map the lowmem size.
Each TLB entry can map 4MB, 16MB, 64MB or 256MB, so the failure
is observed when the kernel lowmem size is not equal to the
sum of up to 3 of those values.

Does this mean you cannot run 1G of lowmem on a 85xx?

On 82xx I run 1G of lowmem, and when we finaly upgrade our product to a
85xx something, Iw was planning on doing the same.

(For those interested:
To run 1G lowmwm on 82xx (at least under arch/ppc)
CONFIG_ADVANCED_OPTIONS=3Dy
CONFIG_HIGHMEM_START=3D0xfe000000
CONFIG_LOWMEM_SIZE_BOOL=3Dy
CONFIG_LOWMEM_SIZE=3D0x40000000
CONFIG_KERNEL_START_BOOL=3Dy
CONFIG_KERNEL_START=3D0xa0000000