Re: [PATCH] ARC: [hsdk] Make it easier to add PAE40 region to DTB

From: Vineet Gupta
Date: Wed Apr 03 2019 - 12:44:37 EST

On 4/3/19 9:34 AM, Eugeniy Paltsev wrote:
>> - reg = <0x80000000 0x40000000>; /* 1 GiB */
>> + reg = <0x0 0x80000000 0x0 0x40000000>; /* 1 GB lowmem */
>> + /* 0x1 0x00000000 0x0 0x40000000>; 1 GB highmem */
> Could you please get rid of comment with reference for PAE40/HIGHMEM region in this patch?
> It gives wrong expectations that if we uncomment it and enable PAE40 in config we'll get working system.
> But it isn't true - we also need to remap AXI apertures appropriately.

Well I didn't have to do any remapping for successfully running a cross glibc
testsuite over ssh.
This was v5.1-rc1 + HIGHMEM+ PAE + patch to disable ioc + this patch for DT update.

Perhaps the remapping is needed when you are remapping DDR to 0 (for HIGHMEM + !PAE)

> Otherwise kernel will crush somewhere. Moreover kernel will crush for different reasons in case of launch
> via U-boot and via MDB (because we remap AXI apertures in U-boot for internal purposes).

This was all via mdb !

> If you really want to keep this - I can send you patch with AXI apertures remapping we need to apply firstly.

Well I can drop the last commented line but I don't want to do wholesale changes
to DT for enabling DT, so would liek to keep the rest of the patch anyways.

But sure send over the AXI remapping stuff - is that described in hsdk specs ?