On Wed, Jul 29, 2026 at 04:48:55PM +0530, Anshul Dalal wrote: > From: Hari Nagalla <[email protected]> > > AM62-SIP SK boards have only 512 MB SDRAM. u-boot relocates the kernel > DTB to upper SDRAM region before starting Linux kernel. This region is > overlapping with the Firmware IPC carveouts. To avoid the overlap, set > 'fdt_high' environment variable in u-boot to prevent relocation of DT > blob. > > without this patch: > Booting using the fdt blob at 0x88000000 > Working FDT set to 88000000 > Loading Device Tree to 000000009ce49000, end 000000009ce5b8f9 ... OK > Working FDT set to 9ce49000 > ... > and subsequently during Linux boot carveout reserve memory fails: > > Starting kernel ... > ... > [ 0.000000] printk: legacy bootconsole [ns16550a0] enabled > [ 0.000000] efi: UEFI not found. > [ 0.000000] OF: reserved mem: Reserved memory: failed to reserve > memory for node 'memory@9cc00000': base 0x000000009cc00000, size 14 MiB > [ 0.000000] Reserved memory: created CMA memory pool at > 0x0000000094600000, size 128 MiB > > with the patch: > Booting using the fdt blob at 0x88000000 > Working FDT set to 88000000 > Using Device Tree in place at 0000000088000000, end 0000000088013375 > Working FDT set to 88000000 > ... > and subsequent Linux boot > [ 0.000000] efi: UEFI not found. > [ 0.000000] OF: reserved mem: Reserved memory: reserved region for > node 'memory@9cc00000': base 0x000000009cc00000, size 14 MiB > > Signed-off-by: Hari Nagalla <[email protected]> > Signed-off-by: Anshul Dalal <[email protected]> > --- > During linux boot on AM62x SIP board, U-Boot relocates the fdt to > reserved-memory regions for IPC. This causes the kernel to fail when > trying to reserve said memory regions. > > I'm not sure on what's the correct fix here but this RFC addresses the > problem by disabling relocation to begin with.
The correct fix is to set bootm_size right, among other possibilities. Please look up some of the older threads where I've explained why disabling fdt relocation is wrong. -- Tom
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