Messages in this thread | | | From | Heiko Stuebner <> | Subject | Re: [PATCH V4 2/3] dt-bindings: update riscv plic compatible string | Date | Sat, 16 Oct 2021 18:31:47 +0200 |
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Am Samstag, 16. Oktober 2021, 14:56:51 CEST schrieb Guo Ren: > On Sat, Oct 16, 2021 at 6:35 PM Heiko Stuebner <heiko@sntech.de> wrote: > > > > Hi Guo, > > > > Am Samstag, 16. Oktober 2021, 05:21:59 CEST schrieb guoren@kernel.org: > > > From: Guo Ren <guoren@linux.alibaba.com> > > > > > > Add the compatible string "thead,c900-plic" to the riscv plic > > > bindings to support allwinner d1 SOC which contains c906 core. > > > > The compatible strings sound good now, but some things below > > > > > > > > Signed-off-by: Guo Ren <guoren@linux.alibaba.com> > > > Cc: Rob Herring <robh@kernel.org> > > > Cc: Palmer Dabbelt <palmerdabbelt@google.com> > > > Cc: Anup Patel <anup@brainfault.org> > > > Cc: Atish Patra <atish.patra@wdc.com> > > > > > > --- > > > > > > Changes since V4: > > > - Update description in errata style > > > - Update enum suggested by Anup, Heiko, Samuel > > > > > > Changes since V3: > > > - Rename "c9xx" to "c900" > > > - Add thead,c900-plic in the description section > > > --- > > > .../interrupt-controller/sifive,plic-1.0.0.yaml | 11 ++++++++++- > > > 1 file changed, 10 insertions(+), 1 deletion(-) > > > > > > diff --git a/Documentation/devicetree/bindings/interrupt-controller/sifive,plic-1.0.0.yaml b/Documentation/devicetree/bindings/interrupt-controller/sifive,plic-1.0.0.yaml > > > index 08d5a57ce00f..272f29540135 100644 > > > --- a/Documentation/devicetree/bindings/interrupt-controller/sifive,plic-1.0.0.yaml > > > +++ b/Documentation/devicetree/bindings/interrupt-controller/sifive,plic-1.0.0.yaml > > > @@ -35,6 +35,12 @@ description: > > > contains a specific memory layout, which is documented in chapter 8 of the > > > SiFive U5 Coreplex Series Manual <https://static.dev.sifive.com/U54-MC-RVCoreIP.pdf>. > > > > > > + The C9xx PLIC does not comply with the interrupt claim/completion process defined > > > + by the RISC-V PLIC specification because C9xx PLIC will mask an IRQ when it is > > > + claimed by PLIC driver (i.e. readl(claim) and the IRQ will be unmasked upon > > > + completion by PLIC driver (i.e. writel(claim). This behaviour breaks the handling > > > + of IRQS_ONESHOT by the generic handle_fasteoi_irq() used in the PLIC driver. > > > + > > > maintainers: > > > - Sagar Kadam <sagar.kadam@sifive.com> > > > - Paul Walmsley <paul.walmsley@sifive.com> > > > @@ -46,7 +52,10 @@ properties: > > > - enum: > > > - sifive,fu540-c000-plic > > > - canaan,k210-plic > > > - - const: sifive,plic-1.0.0 > > > + - enmu: > > > > ^ spelling enum > > > > > + - sifive,plic-1.0.0 > > > + - thead,c900-plic > > > + - allwinner,sun20i-d1-plic > > > > but in general I'd think that you want something like > > > > compatible: > > oneOf: > > - items: > > - enum: > > - sifive,fu540-c000-plic > > - canaan,k210-plic > > - const: sifive,plic-1.0.0 > > - items: > > - enum: > > - allwinner,sun20i-d1-plic > > - const: thead,c900-plic > > > > Having only one item list would allow as valid combinations like > > "sifive,fu540-c000-plic", "thead,c900-plic" when checking the schema. > > > > With the oneOf and separate lists we can make sure that such > > "illegal" combinations get flagged by the dtbs_check > > > > [the enum with the single allwinner entry already leaves > > room for later addition to the c900-plic variant] > Thx, I'll fix it in the next version. > > another question: Is the allwinner_sun20i_d1_plic needed to IRQCHIP_DECLARE? > > +IRQCHIP_DECLARE(thead_c900_plic, "thead,c900-plic", thead_c900_plic_init); > +IRQCHIP_DECLARE(allwinner_sun20i_d1_plic, "allwinner,sun20i-d1-plic", > thead_c900_plic_init);
Doing IRQCHIP_DECLARE(thead_c900_plic, "thead,c900-plic", thead_c900_plic_init); should be enough for now.
Compatible-parsing happens from left to right, from most-specific to most-generic. So having the allwinner-d1 compatible in there is sort of a safeguard.
If at some _later point in time_ , some specific new quirk of the D1 implementation comes to light, we can _then_ just add a IRQCHIP_DECLARE(allwinner_d1_plic, "allwinner,sun20i-d1-plic", allwinner_d1_plic_init);
Devicetrees should be stable and newer kernels should work with old devicetrees, so having the soc-specific compatible in there just makes it future proof :-)
Heiko
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