hello Heinrich, On Sat, 5 Dec 2020 at 15:01, Heinrich Schuchardt <xypron.g...@gmx.de> wrote:
> On 11/26/20 7:40 PM, Sughosh Ganu wrote: > > The Qemu platform emulator generates a device tree blob and places it > > at the start of the dram, which is then used by u-boot. Use this dtb > > only if CONFIG_OF_BOARD is defined. This allows using a different > > device tree, using the CONFIG_OF_SEPARATE option. This dtb is attached > > to the u-boot binary as a u-boot-fdt.bin file > > Dear Sughosh, > > thank your for this series which will allow us to better demonstrate and > test capsule updates. > > I am not sure if the approach that you take at device-trees here is the > right one. > > On QEMU the device-tree is generated on the fly by the QEMU binary > depending on which devices the user has specified. > > Your idea is to replace this device-tree completely to be able to add > extra elements (the EFI signature list, see patch 2/14). Thus a > device-tree might be loaded that does not match the user selected devices. > > An alternative approach would be to apply all additions to the > device-tree as an FDT overlay (or fixup). This would allow the dynamic > parts of the QEMU device-tree still to be passed through. > I will take a look at storing the public key as part of the fdt overlay, with a runtime fixup. Although, I think the issue that you are pointing to would be specific to Qemu and not other platforms. But I do see the merit in having the public-key certificate stored as part of an overlay. If I hit any issues while implementing this, I will get back to you. Thanks. -sughosh > Could you, please, assess the pros and cons of the two approaches with > respect to: > > * usability for capsule updates > * applicability for non-QEMU systems > * integration of DTB overlays with FIT images for other use cases > > Best regards > > Heinrich > > > > > > Signed-off-by: Sughosh Ganu <sughosh.g...@linaro.org> > > --- > > board/emulation/qemu-arm/qemu-arm.c | 2 ++ > > 1 file changed, 2 insertions(+) > > > > diff --git a/board/emulation/qemu-arm/qemu-arm.c > b/board/emulation/qemu-arm/qemu-arm.c > > index f18f2ed7da..e146d1cc50 100644 > > --- a/board/emulation/qemu-arm/qemu-arm.c > > +++ b/board/emulation/qemu-arm/qemu-arm.c > > @@ -89,11 +89,13 @@ int dram_init_banksize(void) > > return 0; > > } > > > > +#if defined(CONFIG_OF_BOARD) > > void *board_fdt_blob_setup(void) > > { > > /* QEMU loads a generated DTB for us at the start of RAM. */ > > return (void *)CONFIG_SYS_SDRAM_BASE; > > } > > +#endif > > > > void enable_caches(void) > > { > > > >