Hello, On 4/27/20 10:07 AM, Sascha Hauer wrote: > On Mon, Apr 27, 2020 at 09:13:49AM +0200, Ahmad Fatoum wrote: >> `mw 0x20d8040 0x08000030; mw 0x20d8044 0x10000000; reset` issued on an >> i.MX6Q forces boot from the ecspi1. This is because the BootROM reads >> the boot mode out of SRC_GPR9 instead of SRC_SBMR1 whenever SRC_GPR10 >> has its 28th bit set. > > Is this documented somewhere? The reference Manual marks SRC_GPR9 and > SRC_GPR10 as > > | This register is used by the ROM code and should not be used > | by application software. Not documented anywhere, except for U-Boot's bmode command and boot source determination code: https://github.com/trini/u-boot/blob/v2020.04/arch/arm/mach-imx/mx6/soc.c#L560 https://github.com/trini/u-boot/blob/v2020.04/arch/arm/mach-imx/init.c#L104 > And why do you depend on this behaviour? It's a useful debugging aid, when strap pins aren't easily accessible, because then your only other option is then to fuse to affect the boot (or short your SPI I/O pins). I am preparing code to provide a generic reboot mode functionality in barebox. This would among others cover the functionality of the U-Boot bmode command and these patches here are prerequisites, so the boot source detection remains accurate. Cheers > > Sascha > -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ barebox mailing list barebox@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/barebox
