Hi Peter, On Wed, 11 Dec 2024 at 09:27, Peter Robinson <pbrobin...@gmail.com> wrote: > > > > On Mon, 9 Dec 2024 at 19:55, Simon Glass <s...@chromium.org> wrote: >> >> Set this option so that all boot images stay within the bottom 512MB of >> memory. This should allow us to drop the fdt_high and initrd_high >> options. > > > How does this work for a device with < 256Mb of RAM? There's a number of the > original RPi series that have 256Mb of RAM and that equates to less than that > due to reservations for the vendor firmware.
Looking at boot_relocate_fdt(), this is just a maximum, and lmb is used to allocate the FDT / cmdline. So this patch shouldn't affect that. But the later patch to move the ramdisk up will cause problems. Based on the comment, a 256MB (I assume you mean) device can have as little as 64MB of RAM available to the ARM core, which is not enough to load a ramdisk from the new start-address of about 90MB. I found an old rpi1 which I could hook up to my lab, perhaps. Could you point me to a distro-image that boots OK on that, ideally with only 64MB available? > >> >> Signed-off-by: Simon Glass <s...@chromium.org> >> Reviewed-by: Tom Rini <tr...@konsulko.com> >> Suggested-by: Tom Rini <tr...@konsulko.com> >> --- >> >> Changes in v3: >> - Add to the existing comment block >> >> Changes in v2: >> - Add new patch to set bootm_size >> >> board/raspberrypi/rpi/rpi.env | 5 +++++ >> 1 file changed, 5 insertions(+) >> >> diff --git a/board/raspberrypi/rpi/rpi.env b/board/raspberrypi/rpi/rpi.env >> index 30228285edd..a327fccc77f 100644 >> --- a/board/raspberrypi/rpi/rpi.env >> +++ b/board/raspberrypi/rpi/rpi.env >> @@ -60,7 +60,12 @@ dfu_alt_info+=zImage fat 0 1 >> * Even with the smallest possible CPU-GPU memory split of the CPU getting >> * only 64M, the remaining 25M starting at 0x02700000 should allow quite >> * large initrds before they start colliding with U-Boot. >> + * >> + * Limit bootm_size to 512MB so that all boot images stay within the bottom >> + * 512MB of memory >> */ >> +bootm_size=0x20000000 >> + >> #ifdef CONFIG_ARM64 >> fdt_high=ffffffffffffffff >> initrd_high=ffffffffffffffff >> -- >> 2.34.1 >>
