Messages in this thread | | | Date | Tue, 22 Mar 2022 09:46:19 +0530 | Subject | Re: [PATCH v1 2/4] arm64: dts: qcom: sc7280: Add 'piglin' to the crd-r3 compatible strings | From | Rajendra Nayak <> |
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On 3/21/2022 11:30 PM, Doug Anderson wrote: > "Hi, > > On Mon, Mar 21, 2022 at 8:14 AM Matthias Kaehlcke <mka@chromium.org> wrote: >> >> On Mon, Mar 21, 2022 at 11:14:56AM +0530, Rajendra Nayak wrote: >>> >>> On 3/17/2022 5:58 AM, Matthias Kaehlcke wrote: >>>> With newer bootloader versions the crd-r3 (aka CRD 1.0 and 2.0) is >>>> identified as a 'piglin' board (like the IDP2 board), instead of 'hoglin' >>>> Add the compatible strings 'google,piglin-rev{3,4}'. The hoglin entries >>>> are kept to make sure the board keeps booting with older bootloader >>>> versions. >>> >>> The older bootloaders really look for the google,hoglin-rev3/google,hoglin-rev4 >>> compatibles or just google,hoglin? If its just google,hoglin, won;t it pick the >>> crd-rev5+ dtb now? >> >> They look for the -revN compatible, I confirmed that on my CRD 2.0. > > Thanks for confirming Matthias! I'll also note that, in general, these > "google,board-revX" type compatible strings are all programmatically > generated. You can see at: > > https://chromium.googlesource.com/chromiumos/platform/depthcharge/+/refs/heads/main/src/boot/fit.c#70 > > ...and whenever it's using this normal logic then it has a standard > fallback mechanism in place. On a random board in front of me > depthcharge prints out: > > Compat preference: google,lazor-rev3-sku0 google,lazor-rev3 > google,lazor-sku0 google,lazor > > So it'll first try the very specific verison with rev and sku. Then > just by rev. Then just by sku. ...and if none of those match it'll > pick a device tree that has neither. The "newest" device tree always > has no revision number specified and that way if software doesn't > change but the revision bumps then we have no problem. We only add the > revision info for old boards.
Thanks Matthias/Doug for the clarification,
Reviewed-by: Rajendra Nayak <quic_rjendra@quicinc.com>
> > There are a few cases where we add special compatible strings and > these don't match on board/rev. This is fairly uncommon, though. You > might be aware of the special case of adding "qcom,sc7180-idp" > (without rev/sku matching) for "bubs". See: > > https://chromium.googlesource.com/chromiumos/platform/depthcharge/+/refs/heads/main/src/board/trogdor/board.c#136 > > > -Doug
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