* Ladislav Michl <oss-lists@xxxxxxxxx> [230418 12:03]: > Hi Tony, > > On Tue, Apr 18, 2023 at 12:43:03PM +0300, Tony Lindgren wrote: > > Hi, > > > > * Ladislav Michl <oss-lists@xxxxxxxxx> [230413 12:56]: > > > Export SRAM using nvmem. > > > > Patch looks good to me, just wondering how this is used.. > > This has been sitting in my tree for over five years and it is used > to store boot state. Patches for u-boot are pending here as well, > but I'll do my best to upstream reasonable parts of them. > > All was done for failsafe device updating using A/B scheme. Device > is also using U-Boot's Falcon mode to speed things up, so SPL > loads kernel directly from UBI volume. To decide which one to load > and boot, information from NVRAM is used - there is no other memory > except NVRAM and NAND. I didn't want to use NAND for this purpose, > see bellow how NVRAM failures are handled. > > > Are we just exporting the nvram via sysfs for userspace to use it > > for whatever, or is there also some RTC core layer use for it? > > RTC itself is not using it. My board is using RAUC for updates: > https://rauc.readthedocs.io/en/latest/examples.html#symmetric-a-b-setup OK thanks for the detailed information :) Regards, Tony
