On 14.03.2023 05:48, Prasad Sodagudi wrote: > > > On 3/9/2023 3:47 PM, Konrad Dybcio wrote: >> >> >> On 10.03.2023 00:39, Eric Chanudet wrote: >>> ABL uses the __symbols__ section to process the DTB before passing it >>> forward. Without it, the bootstrap is interrupted. >>> >>> Signed-off-by: Eric Chanudet <echanude@xxxxxxxxxx> >>> --- >> Fix your ABL. > Hi Konrad, > > Apps boot-loader need __symbols__ for dynamic overlay operation. Qualcomm firmware passes an overlay file to apps boot-loader to overlay some of the nodes based on firmware configuration. Without __symbols__ apps boot-loader is not able to overlay. Yes/no. There are a plenty of libfdt functions that let you do that, especially if you know something about the node. > > Qualcomm hypervisor/gunyah would like to overlay arch timer node with always-on property, So adding __symbols__ helps boot-loader to overlay. For the arch timer, you can simply iterate over the top-level nodes (or in the worst case scenario, over all nodes which would not take very long on cortex-a / cortex-x cores) and look for the specific timer compatible that has been with us for like 10 years at this point and use libfdt's fdt_add_property without overlays. > > I think, commit text is misleading here and I will request Eric to fix the commit text. Sort of, but then the design you explained is very error-prone as it's dependent on the device tree always satisfying your hypervisor's needs. Konrad > > -Thanks, Prasad > >> >> Konrad >>> Depends on initial sa8775p-ride.dts: >>> https://lore.kernel.org/all/20230214092713.211054-3-brgl@xxxxxxxx/ >>> >>> arch/arm64/boot/dts/qcom/Makefile | 4 ++++ >>> 1 file changed, 4 insertions(+) >>> >>> diff --git a/arch/arm64/boot/dts/qcom/Makefile b/arch/arm64/boot/dts/qcom/Makefile >>> index b63cd1861e68..72e85ab31d74 100644 >>> --- a/arch/arm64/boot/dts/qcom/Makefile >>> +++ b/arch/arm64/boot/dts/qcom/Makefile >>> @@ -1,4 +1,8 @@ >>> # SPDX-License-Identifier: GPL-2.0 >>> + >>> +# Enable support for device-tree overlays required on sa8775p-ride. >>> +DTC_FLAGS_sa8775p-ride := -@ >>> + >>> dtb-$(CONFIG_ARCH_QCOM) += apq8016-sbc.dtb >>> dtb-$(CONFIG_ARCH_QCOM) += apq8094-sony-xperia-kitakami-karin_windy.dtb >>> dtb-$(CONFIG_ARCH_QCOM) += apq8096-db820c.dtb >> >>
