> Am 13.04.2016 um 19:00 schrieb Stephen Warren <[email protected]>: > >> On 04/13/2016 09:51 AM, Alexander Graf wrote: >>> On 04/13/2016 05:31 PM, Stephen Warren wrote: >>>> On 04/13/2016 06:55 AM, Andreas Färber wrote: >>>>> Am 13.04.2016 um 14:48 schrieb Andreas Färber: >>>>> The 4.5.0 kernel cannot cope with U-Boot's internal device tree, and >>>>> the >>>>> distro boot commands are looking for $fdtfile, so provide it to avoid >>>>> having users supply a dumb boot.scr doing a setenv fdtfile ...; boot, >>>>> defeating the purpose of generic EFI boot. >>>>> >>>>> Cc: Stephen Warren <[email protected]> >>>>> Cc: Alexander Graf <[email protected]> >>>>> Signed-off-by: Andreas Färber <[email protected]> >>>>> --- >>>>> include/configs/jetson-tk1.h | 4 ++++ >>>>> 1 file changed, 4 insertions(+) >>>>> >>>>> diff --git a/include/configs/jetson-tk1.h >>>>> b/include/configs/jetson-tk1.h >>>>> index 59dbb20..82a4be4 100644 >>>>> --- a/include/configs/jetson-tk1.h >>>>> +++ b/include/configs/jetson-tk1.h >>>>> @@ -63,6 +63,10 @@ >>>>> /* General networking support */ >>>>> #define CONFIG_CMD_DHCP >>>>> >>>>> +#define BOARD_EXTRA_ENV_SETTINGS \ >>>>> + "fdtfile=tegra124-jetson-tk1.dtb\0" \ >>>>> + "" >>>> >>>> Is there any more intelligent solution than doing this for each board? >>> >>> Yes, the distro boot scripts shouldn't be using $fdtfile >>> unconditionally since it's not guaranteed to be set. The model is that >>> boot scripts determine the FDT filename, and $fdtfile is an optional >>> override. >> >> The point of all of the efi magic is that we can completely get rid of >> boot scripts. Boards use the distro scripts, everything else gets >> implicitly detected and executed. The way other boards deal with common >> code mapping into separate boards is to either implement a "findfdt" >> scriptlet or directly write the fdtfile variable (e.g. beaglebone) in >> board init (e.g. rpi). >> >>> It looks like the hard-coded use of $fdtfile was added into the EFI >>> path, which I didn't get to review, and which shouldn't be enabled by >>> default but unfortunately is. >> >> s/un// :) >> >> Just imagine a world where people don't have to worry about bootloaders >> anymore. Things would "just work". You plug in a usb stick, it comes up, >> boots Linux, everthing goes without anyone touching boot scripts, >> downloading board specific files, etc. You could get a random >> distribution from a common download page from somewhere and just run it. >> >> Well, you can also just look at any random x86 system. They get at least >> that part pretty right these days. > > Well, you can also get the same benefit using extlinux.conf, and without > relying on EFI:-P > > Anyway, nothing in your benefits-of-EFI statement implies that relying on > $fdtfile being set is correct. That's a new requirement that didn't exist > before. Either the requirement needs to be removed (e.g. using a default FDT > filename such as "${soc}-${board}${boardver}.dts") or only enabling this > functionality on boards that do set $fdtfile, since it relies on that.
On boards that fon't set fdtfile we just don't load it, because we can't find the file. So you're getting a working grub2 payload, but Linux gets an empty device tree unless you pass it in using the grub2 "devicetree" command. It's really just a convenience helper. And a nice piece to the puzzle that by convention allows users to think less about u-boot internals. The efi code works fine without. Alex _______________________________________________ U-Boot mailing list [email protected] http://lists.denx.de/mailman/listinfo/u-boot
