23 Mar
2018
23 Mar
'18
10:42 a.m.
On Fri, Mar 23, 2018 at 5:39 PM, Maxime Ripard maxime.ripard@bootlin.com wrote:
On Fri, Mar 23, 2018 at 04:18:53PM +0800, Icenowy Zheng wrote:
Allwinner 64-bit SoCs can use 4GiB DRAM chip, however their memory map has only allocated 3GiB for DRAM, so only 3GiB of the DRAM is accessible.
How would that work in Linux?
Add a Kconfig option for the maximum accessible DRAM.
For A80 it should be a much higher value (8GiB), but as I have no A80 device to test and originally U-Boot only supports 2GiB DRAM on A80, it currently still falls under the 2GiB situation.
I guess we have LPAE on armv7 to deal with this nicely.
AFAIK even though we do have LPAE, the hardware bus is not wired up to take advantage of it. :(
ChenYu