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Subject: Re: [PATCH v3 6/7] riscv: dts: add initial canmv-k230 and k230-evb
 dts
From: Yangyu Chen <cyy@cyyself.name>
In-Reply-To: <mhng-f1aa91d4-211f-4eb4-a94d-a9d88b0d3f6a@palmer-ri-x1c9>
Date: Wed, 6 Mar 2024 00:22:14 +0800
Cc: linux-riscv@lists.infradead.org,
 Conor Dooley <conor@kernel.org>,
 dlemoal@kernel.org,
 robh+dt@kernel.org,
 krzysztof.kozlowski+dt@linaro.org,
 Paul Walmsley <paul.walmsley@sifive.com>,
 Albert Ou <aou@eecs.berkeley.edu>,
 guoren@kernel.org,
 devicetree@vger.kernel.org,
 linux-kernel@vger.kernel.org
Content-Transfer-Encoding: quoted-printable
References: <mhng-f1aa91d4-211f-4eb4-a94d-a9d88b0d3f6a@palmer-ri-x1c9>
To: Palmer Dabbelt <palmer@dabbelt.com>


> On Mar 5, 2024, at 23:54, Palmer Dabbelt <palmer@dabbelt.com> wrote:
>=20
> On Mon, 04 Mar 2024 13:06:00 PST (-0800), cyy@cyyself.name wrote:
>> Add initial dts for CanMV-K230 and K230-EVB powered by Canaan =
Kendryte
>> K230 SoC [1].
>>=20
>> Some key consideration:
>> - Only place BigCore which is 1.6GHz RV64GCBV
>>=20
>> The existence of cache coherence between the two cores remains =
unknown
>> since they have dedicated L2 caches. And the factory SDK uses it for
>> other OS by default. I don't know whether the two CPUs on K230 SoC
>> can be used in one system. So only place BigCore here.
>>=20
>> Meanwhile, although docs from Canaan said 1.6GHz Core with Vector is
>> CPU1, the csr.mhartid of this core is 0.
>>=20
>> - Support for "zba" "zbb" "zbc" "zbs" are tested by hand
>>=20
>> The user manual of C908 from T-Head does not document it =
specifically.
>> It just said it supports B extension V1.0-rc1. [2]
>=20
> I'm seeing
>=20
>   3.1.6 Vector instruction set (RVV)
>   For more information, see RISC-V =E2=80=9CV=E2=80=9DVector =
Extension, Version    1.0-rc1-20210608
>   =
URL=EF=BC=9Ahttps://github.com/riscv/riscv-v-spec/releases/download/v1.0-r=
c1/riscv-v-spec-1.0-rc1.pdf
>=20
>   3.1.7 Bit operation instruction set (RV64B)
>   For more information, see =EF=BC=9ARISC-V Bit-Manipulation =
ISA-extensions,    Version 1.0.0, 2021-06-12: public review
>   =
URL=EF=BC=9Ahttps://github.com/riscv/riscv-bitmanip/releases/download/1.0.=
0/bitmanip-1.0.0.pdf
>=20
> so I think maybe that's vector 1.0-rc1 and the final bitmanip?
>=20

Yeah. I just want to say what subset of the B extension is supported by
C908.

>> I have tested it by using this [3] which attempts to execute =
"add.uw",
>> "andn", "clmulr", "bclr" and they doesn't traps on K230. But on =
JH7110,
>> "clmulr" and "bclr" will trap.
>>=20
>> - Support for "zicbom" is tested by hand
>>=20
>> Have tested with some out-of-tree drivers from [4] that need DMA and =
they
>> do not come to the dts currently.
>>=20
>> - Cache parameters are inferred from T-Head docs [2] and Canaan docs =
[1]
>>=20
>> L1i: 32KB, VIPT 4-Way set-associative, 64B Cacheline
>> L1d: 32KB, VIPT 4-Way set-associative, 64B Cacheline
>> L2: 256KB, PIPT 16-way set-associative, 64B Cacheline
>>=20
>> The numbers of cache sets are calculated from these parameters.
>>=20
>> - MMU only supports Sv39
>>=20
>> Since T-Head docs [2] say C908 should support Sv48. However, it will =
fail
>> during the kernel probe when running Linux on K230. I also tested it =
by
>> hand on M-Mode software, writing Sv48 to satp.mode will not trap but =
will
>> leave the csr unchanged. While writing Sv39 it will take effect. It =
shows
>> that this CPU does not support Sv48.
>=20
> I think that only works due to a bug in our sv48 probing routines -- =
unless I'm missing something, we mixed up the sv57 and sv48 probing and =
if sv57 fails to probe then we disable sv48 as well.  So I think we =
probably need some cleanup in there.
>=20

However, the sv48 probing routines work on some other chips with sv48. =
At
least I have tested mainline kernel v6.8-rc2. And the attempt to write =
sv48
to satp by hand tells me it does not support sv48. I think it might be
configurable from CPU RTL, and the K230 taped out with no sv48 support.

>> - Svpbmt and T-Head MAEE both supported
>>=20
>> T-Head C908 does support both Svpbmt and T-Head MAEE for page-based =
memory
>> attributes and is controlled by csr.mxstatus. If the kernel wants to =
use
>> svpbmt, the m-mode software should set BIT(21) of csr.mxstatus to =
zero
>> before entering the s-mode kernel. Otherwise, the kernel will not =
boot as 0
>> on T-Head MAEE represent to NonCachable Memory and it will lose dirty =
cache
>> lines modification that haven't been written back to the memory.
>=20
> So I guess we need the bootloader to just be accurate here?  ie: =
whatever extension it tells S-mode kernels is enabled is how S-mode =
behaves, and then this should just work itself out.
>=20

Yes. Currently, I have patched OpenSBI to disable MAEE. Conor Dooley =
said
from a public irc group that he wants to control the enable of T-Head
variation of zicbom and svpbmt from dts, in addition to mimplid or
something now. I think that will be a better way for the bootloader to =
tell
the kernel whether the T-Head MAEE should be enabled.

Link: =
https://github.com/cyyself/opensbi/commit/b113c1c01d700314a4a696297ec09031=
a9399354

Furthermore, I wonder whether a CPU node like this would be acceptable.
I don't have any other details of how another CPU from K230 SoC works on
Linux.

>> [1] =
https://developer.canaan-creative.com/k230/dev/zh/00_hardware/K230_datashe=
et.html#chapter-1-introduction
>> [2] =
https://occ-intl-prod.oss-ap-southeast-1.aliyuncs.com/resource//1699268369=
347/XuanTie-C908-UserManual.pdf
>> [3] https://github.com/cyyself/rvb_test
>> [4] https://github.com/cyyself/linux/tree/k230-mainline
>>=20
>> Signed-off-by: Yangyu Chen <cyy@cyyself.name>
>> ---
>> arch/riscv/boot/dts/canaan/Makefile       |   2 +
>> arch/riscv/boot/dts/canaan/k230-canmv.dts |  24 ++++
>> arch/riscv/boot/dts/canaan/k230-evb.dts   |  24 ++++
>> arch/riscv/boot/dts/canaan/k230.dtsi      | 140 =
++++++++++++++++++++++
>> 4 files changed, 190 insertions(+)
>> create mode 100644 arch/riscv/boot/dts/canaan/k230-canmv.dts
>> create mode 100644 arch/riscv/boot/dts/canaan/k230-evb.dts
>> create mode 100644 arch/riscv/boot/dts/canaan/k230.dtsi
>>=20
>> diff --git a/arch/riscv/boot/dts/canaan/Makefile =
b/arch/riscv/boot/dts/canaan/Makefile
>> index 987d1f0c41f0..7d54ea5c6f3d 100644
>> --- a/arch/riscv/boot/dts/canaan/Makefile
>> +++ b/arch/riscv/boot/dts/canaan/Makefile
>> @@ -1,6 +1,8 @@
>> # SPDX-License-Identifier: GPL-2.0
>> dtb-$(CONFIG_ARCH_CANAAN) +=3D canaan_kd233.dtb
>> dtb-$(CONFIG_ARCH_CANAAN) +=3D k210_generic.dtb
>> +dtb-$(CONFIG_ARCH_CANAAN) +=3D k230-canmv.dtb
>> +dtb-$(CONFIG_ARCH_CANAAN) +=3D k230-evb.dtb
>> dtb-$(CONFIG_ARCH_CANAAN) +=3D sipeed_maix_bit.dtb
>> dtb-$(CONFIG_ARCH_CANAAN) +=3D sipeed_maix_dock.dtb
>> dtb-$(CONFIG_ARCH_CANAAN) +=3D sipeed_maix_go.dtb
>> diff --git a/arch/riscv/boot/dts/canaan/k230-canmv.dts =
b/arch/riscv/boot/dts/canaan/k230-canmv.dts
>> new file mode 100644
>> index 000000000000..3ab5c8de11a8
>> --- /dev/null
>> +++ b/arch/riscv/boot/dts/canaan/k230-canmv.dts
>> @@ -0,0 +1,24 @@
>> +// SPDX-License-Identifier: GPL-2.0 OR MIT
>> +/*
>> + * Copyright (C) 2024 Yangyu Chen <cyy@cyyself.name>
>> + */
>> +
>> +#include "k230.dtsi"
>> +
>> +/ {
>> + model =3D "Canaan CanMV-K230";
>> + compatible =3D "canaan,canmv-k230", "canaan,kendryte-k230";
>> +
>> + chosen {
>> + stdout-path =3D "serial0:115200n8";
>> + };
>> +
>> + ddr: memory@0 {
>> + device_type =3D "memory";
>> + reg =3D <0x0 0x0 0x0 0x1fdff000>;
>> + };
>> +};
>> +
>> +&uart0 {
>> + status =3D "okay";
>> +};
>> diff --git a/arch/riscv/boot/dts/canaan/k230-evb.dts =
b/arch/riscv/boot/dts/canaan/k230-evb.dts
>> new file mode 100644
>> index 000000000000..42720113c566
>> --- /dev/null
>> +++ b/arch/riscv/boot/dts/canaan/k230-evb.dts
>> @@ -0,0 +1,24 @@
>> +// SPDX-License-Identifier: GPL-2.0 OR MIT
>> +/*
>> + * Copyright (C) 2024 Yangyu Chen <cyy@cyyself.name>
>> + */
>> +
>> +#include "k230.dtsi"
>> +
>> +/ {
>> + model =3D "Kendryte K230 EVB";
>> + compatible =3D "canaan,k230-usip-lp3-evb", "canaan,kendryte-k230";
>> +
>> + chosen {
>> + stdout-path =3D "serial0:115200n8";
>> + };
>> +
>> + ddr: memory@0 {
>> + device_type =3D "memory";
>> + reg =3D <0x0 0x0 0x0 0x1fdff000>;
>> + };
>> +};
>> +
>> +&uart0 {
>> + status =3D "okay";
>> +};
>> diff --git a/arch/riscv/boot/dts/canaan/k230.dtsi =
b/arch/riscv/boot/dts/canaan/k230.dtsi
>> new file mode 100644
>> index 000000000000..0bcff67b78a8
>> --- /dev/null
>> +++ b/arch/riscv/boot/dts/canaan/k230.dtsi
>> @@ -0,0 +1,140 @@
>> +// SPDX-License-Identifier: GPL-2.0 OR MIT
>> +/*
>> + * Copyright (C) 2024 Yangyu Chen <cyy@cyyself.name>
>> + */
>> +
>> +#include <dt-bindings/interrupt-controller/irq.h>
>> +
>> +/dts-v1/;
>> +/ {
>> + #address-cells =3D <2>;
>> + #size-cells =3D <2>;
>> + compatible =3D "canaan,kendryte-k230";
>> +
>> + aliases {
>> + serial0 =3D &uart0;
>> + };
>> +
>> + cpus {
>> + #address-cells =3D <1>;
>> + #size-cells =3D <0>;
>> + timebase-frequency =3D <27000000>;
>> +
>> + cpu@0 {
>> + compatible =3D "thead,c908", "riscv";
>> + device_type =3D "cpu";
>> + reg =3D <0>;
>> + riscv,isa =3D "rv64imafdcv_zba_zbb_zbc_zbs_zicbom_svpbmt";
>> + riscv,isa-base =3D "rv64i";
>> + riscv,isa-extensions =3D "i", "m", "a", "f", "d", "c", "v", "zba", =
"zbb",
>> +        "zbc", "zbs", "zicbom", "zicntr", "zicsr",
>> +        "zifencei", "zihpm", "svpbmt";
>> + riscv,cbom-block-size =3D <64>;
>> + d-cache-block-size =3D <64>;
>> + d-cache-sets =3D <128>;
>> + d-cache-size =3D <32768>;
>> + i-cache-block-size =3D <64>;
>> + i-cache-sets =3D <128>;
>> + i-cache-size =3D <32768>;
>> + next-level-cache =3D <&l2_cache>;
>> + mmu-type =3D "riscv,sv39";
>> +
>> + cpu0_intc: interrupt-controller {
>> + compatible =3D "riscv,cpu-intc";
>> + interrupt-controller;
>> + #interrupt-cells =3D <1>;
>> + };
>> + };
>> +
>> + l2_cache: l2-cache {
>> + compatible =3D "cache";
>> + cache-block-size =3D <64>;
>> + cache-level =3D <2>;
>> + cache-size =3D <262144>;
>> + cache-sets =3D <256>;
>> + cache-unified;
>> + };
>> + };
>> +
>> + apb_clk: apb-clk-clock {
>> + compatible =3D "fixed-clock";
>> + clock-frequency =3D <50000000>;
>> + clock-output-names =3D "apb_clk";
>> + #clock-cells =3D <0>;
>> + };
>> +
>> + soc {
>> + compatible =3D "simple-bus";
>> + interrupt-parent =3D <&plic>;
>> + #address-cells =3D <2>;
>> + #size-cells =3D <2>;
>> + dma-noncoherent;
>> + ranges;
>> +
>> + plic: interrupt-controller@f00000000 {
>> + compatible =3D "canaan,k230-plic" ,"thead,c900-plic";
>> + reg =3D <0xf 0x00000000 0x0 0x04000000>;
>> + interrupts-extended =3D <&cpu0_intc 11>, <&cpu0_intc 9>;
>> + interrupt-controller;
>> + #address-cells =3D <0>;
>> + #interrupt-cells =3D <2>;
>> + riscv,ndev =3D <208>;
>> + };
>> +
>> + clint: timer@f04000000 {
>> + compatible =3D "canaan,k230-clint", "thead,c900-clint";
>> + reg =3D <0xf 0x04000000 0x0 0x04000000>;
>> + interrupts-extended =3D <&cpu0_intc 3>, <&cpu0_intc 7>;
>> + };
>> +
>> + uart0: serial@91400000 {
>> + compatible =3D "snps,dw-apb-uart";
>> + reg =3D <0x0 0x91400000 0x0 0x1000>;
>> + clocks =3D <&apb_clk>;
>> + interrupts =3D <16 IRQ_TYPE_LEVEL_HIGH>;
>> + reg-io-width =3D <4>;
>> + reg-shift =3D <2>;
>> + status =3D "disabled";
>> + };
>> +
>> + uart1: serial@91401000 {
>> + compatible =3D "snps,dw-apb-uart";
>> + reg =3D <0x0 0x91401000 0x0 0x1000>;
>> + clocks =3D <&apb_clk>;
>> + interrupts =3D <17 IRQ_TYPE_LEVEL_HIGH>;
>> + reg-io-width =3D <4>;
>> + reg-shift =3D <2>;
>> + status =3D "disabled";
>> + };
>> +
>> + uart2: serial@91402000 {
>> + compatible =3D "snps,dw-apb-uart";
>> + reg =3D <0x0 0x91402000 0x0 0x1000>;
>> + clocks =3D <&apb_clk>;
>> + interrupts =3D <18 IRQ_TYPE_LEVEL_HIGH>;
>> + reg-io-width =3D <4>;
>> + reg-shift =3D <2>;
>> + status =3D "disabled";
>> + };
>> +
>> + uart3: serial@91403000 {
>> + compatible =3D "snps,dw-apb-uart";
>> + reg =3D <0x0 0x91403000 0x0 0x1000>;
>> + clocks =3D <&apb_clk>;
>> + interrupts =3D <19 IRQ_TYPE_LEVEL_HIGH>;
>> + reg-io-width =3D <4>;
>> + reg-shift =3D <2>;
>> + status =3D "disabled";
>> + };
>> +
>> + uart4: serial@91404000 {
>> + compatible =3D "snps,dw-apb-uart";
>> + reg =3D <0x0 0x91404000 0x0 0x1000>;
>> + clocks =3D <&apb_clk>;
>> + interrupts =3D <20 IRQ_TYPE_LEVEL_HIGH>;
>> + reg-io-width =3D <4>;
>> + reg-shift =3D <2>;
>> + status =3D "disabled";
>> + };
>> + };
>> +};