Re: [PATCH v2 2/2] ARM: dts: Add nvmem node for BCM2711 bootloader public key

[Stefan Wahren]

Hi,

Am 13.04.23 um 21:28 schrieb Tim Gover:
> On Thu, 13 Apr 2023 at 19:44, Stefan Wahren <stefan.wahren@xxxxxxxx> wrote:
> > Hi Ivan,
> >
> > Am 13.04.23 um 20:18 schrieb Ivan T. Ivanov:
> > > On 04-13 18:15, Stefan Wahren wrote:
> > > > Hi Ivan,
> > > >
> > > > Am 13.04.23 um 10:52 schrieb Ivan T. Ivanov:
> > > > > From: Tim Gover <tim.gover@xxxxxxxxxxxxxxx>
> > > > >
> > > > > Make a copy of the bootloader secure-boot public key available to the OS
> > > > > via an nvmem node. The placement information is populated by the
> > > > > Raspberry Pi firmware if a public key is present in the BCM2711
> > > > > bootloader EEPROM.
> > > >
> > > > It would be nice to have a helpful link like:
> > > > https://www.raspberrypi.com/documentation/computers/configuration.html#nvmem-nodes
> > >
> > > Yep, make sense.
> > >
> > > > > +
> > > > > +   /*
> > > > > +    * RPi4 will copy the binary public key blob (if present) from the bootloader
> > > > > +    * into memory for use by the OS.
> > > > > +    */
> > > > > +   blpubkey: nvram@1 {
> > > > > +           compatible = "raspberrypi,bootloader-public-key", "nvmem-rmem";
> > > >
> > > > Yes this looks better, but this introduce a new dtbs_check issue. The new
> > >
> > > Oops, yes, I forgot to make this check.
> > >
> > > > compatible must be documented in
> > > > Documentation/devicetree/bindings/nvmem/rmem.yaml in a separate patch and
> > > > reviewed by the DT guys.
> > >
> > > Or I can drop the new compatible string altogether? It looks like
> > > only alias is strictly required?! Tim Gover is this correct?
> >
> > i cannot speak for the firmware side, but i think we should try to keep
> > it compatible with the vendor DTB here.
>
> The firmware doesn't look at the compatible string. It locates the
> nodes to update using the 'blconfig' and 'blpubkey' aliases. Userspace
> scripts (including the documentation example) should also use these
> aliases.
> Therefore, I don't think it matters if the compatible strings is
> modified, but I won't pretend to know what the correct DT style is
> here :)

okay, regardless of the compatible string the patch must be send to the 
DT maintainers and the devicetree mailing list otherwise they don't have 
any chance to review.

Thanks

> Tim