Re: [PATCH v2 6/7] riscv: dts: sophgo: Separate common devices from cv1800b soc

[Conor Dooley <conor@kernel.org>]

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On Fri, Oct 13, 2023 at 05:52:03PM +0800, Inochi Amaoto wrote:
> Sorry for the wrong title.
> 
> >Yo,
> >
> >On Mon, Oct 09, 2023 at 07:26:35PM +0800, Inochi Amaoto wrote:
> >> Move the cpu and the common peripherals of CV181x and CV180x to new file.
> >>
> >> Signed-off-by: Inochi Amaoto <inochiama@outlook.com>
> >> ---
> >>  arch/riscv/boot/dts/sophgo/cv1800b.dtsi       | 95 +------------------
> >>  .../dts/sophgo/{cv1800b.dtsi => cv180x.dtsi}  | 19 +---
> >>  2 files changed, 2 insertions(+), 112 deletions(-)
> >>  copy arch/riscv/boot/dts/sophgo/{cv1800b.dtsi => cv180x.dtsi} (80%)
> >>
> >> diff --git a/arch/riscv/boot/dts/sophgo/cv1800b.dtsi b/arch/riscv/boot/dts/sophgo/cv1800b.dtsi
> >> index df40e87ee063..0904154f9829 100644
> >> --- a/arch/riscv/boot/dts/sophgo/cv1800b.dtsi
> >> +++ b/arch/riscv/boot/dts/sophgo/cv1800b.dtsi
> >> @@ -3,106 +3,13 @@
> >>   * Copyright (C) 2023 Jisheng Zhang <jszhang@kernel.org>
> >>   */
> >>
> >> -#include <dt-bindings/interrupt-controller/irq.h>
> >> +#include "cv180x.dtsi"
> >>
> >>  / {
> >>  	compatible = "sophgo,cv1800b";
> >> -	#address-cells = <1>;
> >> -	#size-cells = <1>;
> >> -
> >> -	cpus: cpus {
> >> -		#address-cells = <1>;
> >> -		#size-cells = <0>;
> >> -		timebase-frequency = <25000000>;
> >> -
> >> -		cpu0: cpu@0 {
> >> -			compatible = "thead,c906", "riscv";
> >> -			device_type = "cpu";
> >> -			reg = <0>;
> >> -			d-cache-block-size = <64>;
> >> -			d-cache-sets = <512>;
> >> -			d-cache-size = <65536>;
> >> -			i-cache-block-size = <64>;
> >> -			i-cache-sets = <128>;
> >> -			i-cache-size = <32768>;
> >> -			mmu-type = "riscv,sv39";
> >> -			riscv,isa = "rv64imafdc";
> >> -			riscv,isa-base = "rv64i";
> >> -			riscv,isa-extensions = "i", "m", "a", "f", "d", "c", "zicntr", "zicsr",
> >> -					       "zifencei", "zihpm";
> >> -
> >> -			cpu0_intc: interrupt-controller {
> >> -				compatible = "riscv,cpu-intc";
> >> -				interrupt-controller;
> >> -				#address-cells = <0>;
> >> -				#interrupt-cells = <1>;
> >> -			};
> >> -		};
> >> -	};
> >> -
> >> -	osc: oscillator {
> >> -		compatible = "fixed-clock";
> >> -		clock-output-names = "osc_25m";
> >> -		#clock-cells = <0>;
> >> -	};
> >>
> >>  	soc {
> >> -		compatible = "simple-bus";
> >>  		interrupt-parent = <&plic>;
> >> -		#address-cells = <1>;
> >> -		#size-cells = <1>;
> >> -		dma-noncoherent;
> >> -		ranges;
> >> -
> >> -		uart0: serial@4140000 {
> >> -			compatible = "snps,dw-apb-uart";
> >> -			reg = <0x04140000 0x100>;
> >> -			interrupts = <44 IRQ_TYPE_LEVEL_HIGH>;
> >> -			clocks = <&osc>;
> >> -			reg-shift = <2>;
> >> -			reg-io-width = <4>;
> >> -			status = "disabled";
> >> -		};
> >> -
> >> -		uart1: serial@4150000 {
> >> -			compatible = "snps,dw-apb-uart";
> >> -			reg = <0x04150000 0x100>;
> >> -			interrupts = <45 IRQ_TYPE_LEVEL_HIGH>;
> >> -			clocks = <&osc>;
> >> -			reg-shift = <2>;
> >> -			reg-io-width = <4>;
> >> -			status = "disabled";
> >> -		};
> >> -
> >> -		uart2: serial@4160000 {
> >> -			compatible = "snps,dw-apb-uart";
> >> -			reg = <0x04160000 0x100>;
> >> -			interrupts = <46 IRQ_TYPE_LEVEL_HIGH>;
> >> -			clocks = <&osc>;
> >> -			reg-shift = <2>;
> >> -			reg-io-width = <4>;
> >> -			status = "disabled";
> >> -		};
> >> -
> >> -		uart3: serial@4170000 {
> >> -			compatible = "snps,dw-apb-uart";
> >> -			reg = <0x04170000 0x100>;
> >> -			interrupts = <47 IRQ_TYPE_LEVEL_HIGH>;
> >> -			clocks = <&osc>;
> >> -			reg-shift = <2>;
> >> -			reg-io-width = <4>;
> >> -			status = "disabled";
> >> -		};
> >> -
> >> -		uart4: serial@41c0000 {
> >> -			compatible = "snps,dw-apb-uart";
> >> -			reg = <0x041c0000 0x100>;
> >> -			interrupts = <48 IRQ_TYPE_LEVEL_HIGH>;
> >> -			clocks = <&osc>;
> >> -			reg-shift = <2>;
> >> -			reg-io-width = <4>;
> >> -			status = "disabled";
> >> -		};
> >>
> >>  		plic: interrupt-controller@70000000 {
> >>  			compatible = "sophgo,cv1800b-plic", "thead,c900-plic";
> >> diff --git a/arch/riscv/boot/dts/sophgo/cv1800b.dtsi b/arch/riscv/boot/dts/sophgo/cv180x.dtsi
> >> similarity index 80%
> >> copy from arch/riscv/boot/dts/sophgo/cv1800b.dtsi
> >> copy to arch/riscv/boot/dts/sophgo/cv180x.dtsi
> >> index df40e87ee063..ffaf51724c98 100644
> >
> >Firstly, this form of diff really threw me, I was quite confused for a
> >few minutes. A copy plus a pair of diffs doesn't really make much sense,
> >when the operation being carried is an extraction of some nodes to a
> >different file.
> >
> 
> I was told to use -C/-M/-B to generate patch, and the git format-patch
> give me this wired output if I use -C, using -M seems no change from v1.
> The -B output is also disappointing. Maybe I need to generate agaion?

I don't think generating it again is going to change the outcome & I
don't really think the -C version of this patch makes much sense, it is
hard to tell what has actually been moved.

> The v1 version:
> https://lore.kernel.org/linux-riscv/IA1PR20MB495360B632D106BBB833D82ABBCFA@IA1PR20MB4953.namprd20.prod.outlook.com/
> 
> >> --- a/arch/riscv/boot/dts/sophgo/cv1800b.dtsi
> >> +++ b/arch/riscv/boot/dts/sophgo/cv180x.dtsi
> >> @@ -1,12 +1,12 @@
> >>  // SPDX-License-Identifier: (GPL-2.0 OR MIT)
> >>  /*
> >>   * Copyright (C) 2023 Jisheng Zhang <jszhang@kernel.org>
> >> + * Copyright (C) 2023 Inochi Amaoto <inochiama@outlook.com>
> >
> >Also, is moving around some bits of hw description really a
> >copyrightable change?
> >
> 
> It seems to be a mistake when I splitting the patch from v1.
> This copyright should in the next patch.
> 
> >>   */
> >>
> >>  #include <dt-bindings/interrupt-controller/irq.h>
> >>
> >>  / {
> >> -	compatible = "sophgo,cv1800b";
> >>  	#address-cells = <1>;
> >>  	#size-cells = <1>;
> >>
> >> @@ -48,7 +48,6 @@ osc: oscillator {
> >>
> >>  	soc {
> >>  		compatible = "simple-bus";
> >> -		interrupt-parent = <&plic>;
> >>  		#address-cells = <1>;
> >>  		#size-cells = <1>;
> >>  		dma-noncoherent;
> >> @@ -103,21 +102,5 @@ uart4: serial@41c0000 {
> >>  			reg-io-width = <4>;
> >>  			status = "disabled";
> >>  		};
> >> -
> >> -		plic: interrupt-controller@70000000 {
> >> -			compatible = "sophgo,cv1800b-plic", "thead,c900-plic";
> >> -			reg = <0x70000000 0x4000000>;
> >> -			interrupts-extended = <&cpu0_intc 11>, <&cpu0_intc 9>;
> >> -			interrupt-controller;
> >> -			#address-cells = <0>;
> >> -			#interrupt-cells = <2>;
> >> -			riscv,ndev = <101>;
> >> -		};
> >> -
> >> -		clint: timer@74000000 {
> >> -			compatible = "sophgo,cv1800b-clint", "thead,c900-clint";
> >> -			reg = <0x74000000 0x10000>;
> >> -			interrupts-extended = <&cpu0_intc 3>, <&cpu0_intc 7>;
> >> -		};
> >>  	};
> >>  };
> >
> >What I wanted to comment on was this though - it seems that both the
> >cv1800b and the cv1812h have identical plic and clint nodes, other than
> >their compatibles? If that is the case, why create a cv1800b and a
> >cv1812h specific file containing entirely new nodes, when overriding the
> >compatible would be sufficient? Doubly so if the other SoCs in the
> >cv18xx series are going to have identical layouts.
> >
> >I gave it a quick test locally with the below diff applied on top of
> >this series - although I didn't make sure that I didn't re-order the
> >plic & clint nodes, I just wanted to demonstrate what I had done.
> >
> 
> Thanks for demonstration. AFAIK, what you said is true. the most devices
> of CV180x and CV181x are the same, including plic and clint. The reason I
> used a new one is to identify these two devices without making the
> compatible string confusing.
> Should I change the binding name of plic and clint to "sophgo,cv1800-xxx"
> to mark there are the same series? I think this can avoid this confusing
> dt nodes.

I personally don't find the compatibles (or the dt nodes) confusing, so
I dunno. Having reusing the compatible is not something that I am a fan of
either, since this seems to be a different soc (given the sram &
coprocessor etc) even if the addresses of the peripherals are identical.

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