Re: PRAM and reserved memory for Linux

On Wed, Jul 13, 2022 at 10:08:38AM +0000, Joakim Tjernlund wrote:

I added CONFIG_PRAM 4 and a reserved-memory DTS node for the same space but now u-boot complains when booting: ERROR: reserving fdt memory region failed (addr=703ff000 size=1000) The error is caused by arch_lmb_reserve() in arm which seem to reserve command line and board info ?

If I remove the reserved-memory DTS node I don't get a reserved area in Linux, don't quite understand how PRAM is supposed to work?

The first likely problem is that CONFIG_PRAM stuff isn't often used these days so might be glitchy / buggy, as you've found here. Next, I bet that area in arch_lmb_reserve() is about ATAGS/related and should be guarded with CONFIG_SUPPORT_PASSING_ATAGS.