On Tue, Apr 28, 2020 at 8:51 AM Michal Simek <michal.simek@xxxxxxxxxx> wrote: > > On 28. 04. 20 15:23, Rob Herring wrote: > > On Wed, Apr 1, 2020 at 4:23 AM Michal Simek <michal.simek@xxxxxxxxxx> wrote: > >> > >> Hi Rob and others, > >> > >> for couple of years already u-boot is using config node in root DT for > >> u-boot configuration. > >> > >> Here is one example in u-boot source code. > >> https://gitlab.denx.de/u-boot/u-boot/-/blob/master/arch/arm/dts/exynos5250-spring.dts#L47 > >> > >> And here is dt binding description > >> https://gitlab.denx.de/u-boot/u-boot/-/blob/master/doc/device-tree-bindings/config.txt > >> > >> I was checking dt binding specification and there no such a thing > >> described there. It means I expect this is more adhoc u-boot solution. > >> We have reached the point where could be beneficial to put some u-boot > >> specific configurations to DT. > >> > >> Actually I have done similar thing some time ago too by using chosen > >> node and add xilinx specific property there to point to eeprom. > >> https://gitlab.denx.de/u-boot/u-boot/-/blob/master/arch/arm/dts/zynqmp-zcu102-revA.dts#L39 > > > > In this case, I think an alias should be used as it's more of just a > > shortcut to finding a specific node. > > What alias name do you suggest to use? > We have systems where one i2c eeprom described based board and another > i2c eeprom describe bootable module. And I need to have shotcuts to both > of them. > > dt specification doesn't list any keywords for aliases but there is > generic name recommendation. I do want make aliases a registered list of names. > Based on keywords it should look like this. > eeprom0 = ...; > eeprom1 = ...; That was my initial thought, but maybe "nvmemX" to be a bit more generic. > >> I think it is a time to discuss it and do it properly. > >> > >> First of all my question is where we could list SW prefixes to make sure > >> that they are listed and everybody is aware about it. We have > >> vendor-prefixes and we should have a way to record also prefixes for sw > >> projects. U-Boot is using u-boot. Xen has file in the kernel with using > >> xen prefix. At least these two should be listed. > > > > Documentation/devicetree/bindings/vendor-prefixes.yaml. > > thx > > > > >> Next my question is what is the recommended way to pass sw specific > >> parameters via DT? I think using chosen node is more appropriate then > >> adhoc config node. Or is there a better way how this should be done? > > > > /chosen > > > > For vendor specific things though I would be cautious. If they are > > settings for a specific device, then they probably belong in the > > device's node. Second, are they really vendor specific? What we don't > > want is each vendor doing the same thing in slightly different ways. > > For u-boot specific setting like - offsets it should be generic for > everybody. I was already talking to Loic that for saving u-boot > variables to QSPI we should be using MTD partition map and put there > maybe a flag to say that this is the location for storing them. I'd standardize on the partition name. Rob
