On Fri, 2024-11-08 at 06:21 +0100, Heiko Schocher wrote: > Boards which use DCD data in SCFW can drop SPL. > > We tried in our mainline rework to use this approach > too as other imx8qxp boards do in mainline. But we > failed ... it was a hard way to understand the > reason! > > We cannot use DCD image in container as the SCFW > from siemens, does the RAM init on boot itself! > > Siemens SCFW reads the RAM config from i2c eeprom and > dependent on this settings, initializes the RAM. > > Adding DCD data to the bootcontainer will result in > hang of the SCFW, also DCD data in container image is > static which do not fit our needs. > > So we must drop DCD data image, and this has the side > effect that we need SPL, as the task which loads the images > from the container only loads the images to addresses, > and if executed bit is set, starts them. > > As now RAM is not initialized from it, and there is no > option to "wait until SCFW has setup RAM", we can only > load SPL into internal RAM at this point, as than SPL > and SCFW boot parallel. > > The SPL itself than uses the SCU API to communicate
I think there is a typo "than" should be "then"? > with the SCFW and it seems that SCFW only responds to > this API requests when RAM setup is already done by the > SCFW, which has a side-effect of a "sync" for the RAM > setup is done by SCFW! > > We checked if SPL is always save in accessing RAM for > loading images to it! For tests, we added in our RAM > init part in the SCFW long delays (10 seconds and more) > as we thought there is such a sync missing, and we can > break the board through delaying RAM setup... but we > did not managed to fail booting U-Boot from SPL! > > Signed-off-by: Heiko Schocher <[email protected]> > --- > > board/siemens/capricorn/imximage.cfg | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/board/siemens/capricorn/imximage.cfg > b/board/siemens/capricorn/imximage.cfg > index 4350e2967cc..e45f2c9589e 100644 > --- a/board/siemens/capricorn/imximage.cfg > +++ b/board/siemens/capricorn/imximage.cfg > @@ -9,6 +9,10 @@ > > /* Boot from SD, sector size 0x400 */ > BOOT_FROM sd > + > +/* skip DCD data, as firmware initializes the RAM */ > +DCD_SKIP true > + > /* SoC type IMX8QX */ > SOC_TYPE IMX8QX > /* Append seco container image */ -- Walter Schweizer Siemens AG www.siemens.com
