Re: [PATCH v6 10/11] riscv: dts: add initial canmv-k230 and k230-evb dts

Icenowy Zheng
2024-03-24T16:24:33Z

在 2024-03-23星期六的 20:12 +0800，Yangyu Chen写道：
> Add initial dts for CanMV-K230 and K230-EVB powered by Canaan
> Kendryte
> K230 SoC [1].
>
> Some key consideration:
>
> - Only place BigCore which is 1.6GHz RV64GCBV
>
> 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.
>
> Meanwhile, although docs from Canaan said 1.6GHz Core with Vector is
> CPU1, the CSR.MHARTID of this core is 0.

I assume as these two cores do not have any coherency, they are just in
different hartid namespace.

>
> - Support for "zba" "zbb" "zbc" "zbs" are tested by hand
>
> The user manual of C908 from T-Head does not document it
> specifically.
> It just said it supports B extension V1.0. [2]
>
> 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.
>
> - Support for "zicbom" is tested by hand
>
> Have tested with some out-of-tree drivers from [4] that need DMA and
> they
> do not come to the dts currently.
>
> - Cache parameters are inferred from T-Head docs [2] and Canaan docs
> [1]
>
> 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
>
> The numbers of cache sets are calculated from these parameters.
>
> - MMU only supports Sv39
>
> The T-Head docs [2] say the C908 core can be configured to support
> Sv48 and
> Sv39 or only Sv39. On K230, I tried to write "riscv,sv48" on mmu-type
> in
> dts and boot the mainline kernel. However, it failed during the
> kernel
> probe and fell back to Sv39. I also tested it on M-Mode software,
> writing
> Sv48 to satp.mode will not trap but will leave the CSR unchanged.

It's specified by the spec that writing a unsupported mode to SATP will
leave SATP unchanged, and it's also how the kernel detects for Sv48/57.

If a hardware fail to implement this behavior (make SATP changes when
writing an unsupported mode), the kernel will fail to boot and manually
specify MMU mode by putting noXlvl to command line is required. This
behavior may be observed on FSL1030M SoC of Milk-V Vega (if it ever
runs mainline kernel).

> While
> writing Sv39, it will take effect. It shows that this CPU does not
> support
> Sv48.
>
> - Svpbmt and T-Head MAEE both supported
>
> T-Head C908 does support both Svpbmt and T-Head MAEE for page-based
> memory
> attributes and is controlled by BIT(21) on CSR.MXSTATUS. The Svpbmt
> is used
> here for mainline kernel support for K230. If the kernel wants to use
> Svpbmt, the M-Mode software should unset BIT(21) of CSR.MXSTATUS
> before
> entering the S-Mode kernel. Otherwise, the kernel will not boot, as 0
> on
> T-Head MAEE is NonCachable Memory. Once the kernel switches from bare
> metal
> to Sv39, It will lose dirty cache line modifications that haven't
> been
> written back to the memory.

As MXSTATUS has a S-mode read-only mirror known as SXSTATUS, maybe the
kernel should detect SXSTATUS to decide whether to use Svpbmt or
Xtheadpbmt (BTW Svnapot conflicts with Xtheadpbmt too).

>
> [1]
> https://developer.canaan-creative.com/k230/dev/zh/00_hardware/K230_datasheet.html#chapter-1-introduction
> [2]
> https://occ-intl-prod.oss-ap-southeast-1.aliyuncs.com/resource//1699268369347/XuanTie-C908-UserManual.pdf
> [3] https://github.com/cyyself/rvb_test
> [4] https://github.com/cyyself/linux/tree/k230-mainline
>
> 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
>
> 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-$(CONFIG_ARCH_CANAAN) += canaan_kd233.dtb
>  dtb-$(CONFIG_ARCH_CANAAN) += k210_generic.dtb
> +dtb-$(CONFIG_ARCH_CANAAN) += k230-canmv.dtb
> +dtb-$(CONFIG_ARCH_CANAAN) += k230-evb.dtb
>  dtb-$(CONFIG_ARCH_CANAAN) += sipeed_maix_bit.dtb
>  dtb-$(CONFIG_ARCH_CANAAN) += sipeed_maix_dock.dtb
>  dtb-$(CONFIG_ARCH_CANAAN) += 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..9565915cead6
> --- /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 = "Canaan CanMV-K230";
> +       compatible = "canaan,canmv-k230", "canaan,kendryte-k230";
> +
> +       chosen {
> +               stdout-path = "serial0:115200n8";
> +       };
> +
> +       ddr: memory@0 {
> +               device_type = "memory";
> +               reg = <0x0 0x0 0x0 0x20000000>;
> +       };
> +};
> +
> +&uart0 {
> +       status = "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..f898b8e62368
> --- /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 = "Kendryte K230 EVB";
> +       compatible = "canaan,k230-usip-lp3-evb", "canaan,kendryte-
> k230";
> +
> +       chosen {
> +               stdout-path = "serial0:115200n8";
> +       };
> +
> +       ddr: memory@0 {
> +               device_type = "memory";
> +               reg = <0x0 0x0 0x0 0x20000000>;
> +       };
> +};
> +
> +&uart0 {
> +       status = "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..7da49498945e
> --- /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 = <2>;
> +       #size-cells = <2>;
> +       compatible = "canaan,kendryte-k230";
> +
> +       aliases {
> +               serial0 = &uart0;
> +       };
> +
> +       cpus {
> +               #address-cells = <1>;
> +               #size-cells = <0>;
> +               timebase-frequency = <27000000>;
> +
> +               cpu@0 {
> +                       compatible = "thead,c908", "riscv";
> +                       device_type = "cpu";
> +                       reg = <0>;
> +                       riscv,isa =
> "rv64imafdcv_zba_zbb_zbc_zbs_zicbom_svpbmt";
> +                       riscv,isa-base = "rv64i";
> +                       riscv,isa-extensions = "i", "m", "a", "f",
> "d", "c", "v", "zba", "zbb",
> +                                              "zbc", "zbs",
> "zicbom", "zicntr", "zicsr",
> +                                              "zifencei", "zihpm",
> "svpbmt";
> +                       riscv,cbom-block-size = <64>;
> +                       d-cache-block-size = <64>;
> +                       d-cache-sets = <128>;
> +                       d-cache-size = <32768>;
> +                       i-cache-block-size = <64>;
> +                       i-cache-sets = <128>;
> +                       i-cache-size = <32768>;
> +                       next-level-cache = <&l2_cache>;
> +                       mmu-type = "riscv,sv39";
> +
> +                       cpu0_intc: interrupt-controller {
> +                               compatible = "riscv,cpu-intc";
> +                               interrupt-controller;
> +                               #interrupt-cells = <1>;
> +                       };
> +               };
> +
> +               l2_cache: l2-cache {
> +                       compatible = "cache";
> +                       cache-block-size = <64>;
> +                       cache-level = <2>;
> +                       cache-size = <262144>;
> +                       cache-sets = <256>;
> +                       cache-unified;
> +               };
> +       };
> +
> +       apb_clk: apb-clk-clock {
> +               compatible = "fixed-clock";
> +               clock-frequency = <50000000>;
> +               clock-output-names = "apb_clk";
> +               #clock-cells = <0>;
> +       };
> +
> +       soc {
> +               compatible = "simple-bus";
> +               interrupt-parent = <&plic>;
> +               #address-cells = <2>;
> +               #size-cells = <2>;
> +               dma-noncoherent;
> +               ranges;
> +
> +               plic: interrupt-controller@f00000000 {
> +                       compatible = "canaan,k230-plic" ,"thead,c900-
> plic";
> +                       reg = <0xf 0x00000000 0x0 0x04000000>;
> +                       interrupts-extended = <&cpu0_intc 11>,
> <&cpu0_intc 9>;
> +                       interrupt-controller;
> +                       #address-cells = <0>;
> +                       #interrupt-cells = <2>;
> +                       riscv,ndev = <208>;
> +               };
> +
> +               clint: timer@f04000000 {
> +                       compatible = "canaan,k230-clint",
> "thead,c900-clint";
> +                       reg = <0xf 0x04000000 0x0 0x00010000>;
> +                       interrupts-extended = <&cpu0_intc 3>,
> <&cpu0_intc 7>;
> +               };
> +
> +               uart0: serial@91400000 {
> +                       compatible = "snps,dw-apb-uart";
> +                       reg = <0x0 0x91400000 0x0 0x1000>;
> +                       clocks = <&apb_clk>;
> +                       interrupts = <16 IRQ_TYPE_LEVEL_HIGH>;
> +                       reg-io-width = <4>;
> +                       reg-shift = <2>;
> +                       status = "disabled";
> +               };
> +
> +               uart1: serial@91401000 {
> +                       compatible = "snps,dw-apb-uart";
> +                       reg = <0x0 0x91401000 0x0 0x1000>;
> +                       clocks = <&apb_clk>;
> +                       interrupts = <17 IRQ_TYPE_LEVEL_HIGH>;
> +                       reg-io-width = <4>;
> +                       reg-shift = <2>;
> +                       status = "disabled";
> +               };
> +
> +               uart2: serial@91402000 {
> +                       compatible = "snps,dw-apb-uart";
> +                       reg = <0x0 0x91402000 0x0 0x1000>;
> +                       clocks = <&apb_clk>;
> +                       interrupts = <18 IRQ_TYPE_LEVEL_HIGH>;
> +                       reg-io-width = <4>;
> +                       reg-shift = <2>;
> +                       status = "disabled";
> +               };
> +
> +               uart3: serial@91403000 {
> +                       compatible = "snps,dw-apb-uart";
> +                       reg = <0x0 0x91403000 0x0 0x1000>;
> +                       clocks = <&apb_clk>;
> +                       interrupts = <19 IRQ_TYPE_LEVEL_HIGH>;
> +                       reg-io-width = <4>;
> +                       reg-shift = <2>;
> +                       status = "disabled";
> +               };
> +
> +               uart4: serial@91404000 {
> +                       compatible = "snps,dw-apb-uart";
> +                       reg = <0x0 0x91404000 0x0 0x1000>;
> +                       clocks = <&apb_clk>;
> +                       interrupts = <20 IRQ_TYPE_LEVEL_HIGH>;
> +                       reg-io-width = <4>;
> +                       reg-shift = <2>;
> +                       status = "disabled";
> +               };
> +       };
> +};