Re: [PATCH v2 6/8] riscv: dts: Add Tenstorrent Blackhole SoC PCIe cards

[Krzysztof Kozlowski <krzk@kernel.org>]

On 07/10/2025 06:21, Drew Fustini wrote:
> From: Drew Fustini <dfustini@oss.tenstorrent.com>
> 
> Add device tree source describing the Tenstorrent Blackhole SoC and the
> Blackhole P100 and P150 PCIe cards. There are no differences between
> the P100 and P150 cards from the perspective of an OS kernel like Linux
> running on the X280 cores.
> 
> Link: https://github.com/tenstorrent/tt-isa-documentation/blob/main/BlackholeA0/
> Signed-off-by: Drew Fustini <dfustini@oss.tenstorrent.com>
> ---
>  MAINTAINERS                                        |   1 +
>  arch/riscv/boot/dts/Makefile                       |   1 +
>  arch/riscv/boot/dts/tenstorrent/Makefile           |   2 +
>  arch/riscv/boot/dts/tenstorrent/blackhole-card.dts |  14 +++
>  arch/riscv/boot/dts/tenstorrent/blackhole.dtsi     | 104 +++++++++++++++++++++
>  5 files changed, 122 insertions(+)
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 125b5498c3bf8e689adc665fc6e975b05a484abf..b3a2a347f835da952c33b0faf09d560eb1285c32 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -21748,6 +21748,7 @@ L:	linux-riscv@lists.infradead.org
>  S:	Maintained
>  T:	git https://github.com/tenstorrent/linux.git
>  F:	Documentation/devicetree/bindings/riscv/tenstorrent.yaml
> +F:	arch/riscv/boot/dts/tenstorrent/
>  
>  RISC-V THEAD SoC SUPPORT
>  M:	Drew Fustini <fustini@kernel.org>
> diff --git a/arch/riscv/boot/dts/Makefile b/arch/riscv/boot/dts/Makefile
> index 3b99e91efa25be2d6ca5bc173342c24a72f87187..0624199867065dbb5eb62d660f950b4aa3a7abd7 100644
> --- a/arch/riscv/boot/dts/Makefile
> +++ b/arch/riscv/boot/dts/Makefile
> @@ -8,4 +8,5 @@ subdir-y += sifive
>  subdir-y += sophgo
>  subdir-y += spacemit
>  subdir-y += starfive
> +subdir-y += tenstorrent
>  subdir-y += thead
> diff --git a/arch/riscv/boot/dts/tenstorrent/Makefile b/arch/riscv/boot/dts/tenstorrent/Makefile
> new file mode 100644
> index 0000000000000000000000000000000000000000..2c81faaba46235821470b077392ebfebd37ef55a
> --- /dev/null
> +++ b/arch/riscv/boot/dts/tenstorrent/Makefile
> @@ -0,0 +1,2 @@
> +# SPDX-License-Identifier: GPL-2.0
> +dtb-$(CONFIG_ARCH_TENSTORRENT) += blackhole-card.dtb
> diff --git a/arch/riscv/boot/dts/tenstorrent/blackhole-card.dts b/arch/riscv/boot/dts/tenstorrent/blackhole-card.dts
> new file mode 100644
> index 0000000000000000000000000000000000000000..c595f7eddcf860d18193d6b18eb4fd1c0c6c684d
> --- /dev/null
> +++ b/arch/riscv/boot/dts/tenstorrent/blackhole-card.dts
> @@ -0,0 +1,14 @@
> +// SPDX-License-Identifier: (GPL-2.0 OR MIT)
> +/dts-v1/;
> +
> +#include "blackhole.dtsi"
> +
> +/ {
> +	model = "Tenstorrent Blackhole SoC PCIe card";
> +	compatible = "tenstorrent,blackhole-card", "tenstorrent,blackhole";
> +
> +	memory@400030000000 {
> +		device_type = "memory";
> +		reg = <0x4000 0x30000000 0x1 0x00000000>;
> +	};
> +};
> diff --git a/arch/riscv/boot/dts/tenstorrent/blackhole.dtsi b/arch/riscv/boot/dts/tenstorrent/blackhole.dtsi
> new file mode 100644
> index 0000000000000000000000000000000000000000..dc6ac953c34b1efeec231b339251058fac5172d5
> --- /dev/null
> +++ b/arch/riscv/boot/dts/tenstorrent/blackhole.dtsi
> @@ -0,0 +1,104 @@
> +// SPDX-License-Identifier: (GPL-2.0 OR MIT)
> +// Copyright 2025 Tenstorrent AI ULC
> +/dts-v1/;
> +
> +/ {
> +	compatible = "tenstorrent,blackhole";
> +	#address-cells = <2>;
> +	#size-cells = <2>;
> +
> +	cpus {
> +		#address-cells = <0x1>;
> +		#size-cells = <0x0>;

Cells are not hex. Please use decimal everywhere.

> +		timebase-frequency = <50000000>;
> +
> +		cpu@0 {
> +			compatible = "sifive,x280", "sifive,rocket0", "riscv";
> +			device_type = "cpu";
> +			reg = <0>;
> +			mmu-type = "riscv,sv57";
> +			riscv,isa-base = "rv64i";
> +			riscv,isa-extensions = "i", "m", "a", "f", "d", "c", "v", "zicsr",
> +					       "zifencei", "zfh", "zba", "zbb", "sscofpmf";

Blank line

> +			cpu0_intc: interrupt-controller {
> +				compatible = "riscv,cpu-intc";
> +				#interrupt-cells = <1>;
> +				interrupt-controller;
> +			};
> +		};


...

> +
> +		plic0: interrupt-controller@c000000 {
> +			compatible = "tenstorrent,blackhole-plic", "sifive,plic-1.0.0";
> +			reg = <0x0 0x0c000000 0x0 0x04000000>;
> +			interrupts-extended = <&cpu0_intc 11>, <&cpu0_intc 9>,
> +					      <&cpu1_intc 11>, <&cpu1_intc 9>,
> +					      <&cpu2_intc 11>, <&cpu2_intc 9>,
> +					      <&cpu3_intc 11>, <&cpu3_intc 9>;
> +			interrupt-controller;
> +			#interrupt-cells = <1>;
> +			#address-cells = <0>;
> +			riscv,ndev = <128>;



You should have at least serial or any other interface, otherwise I
don't see how this can be used at this stage.


Best regards,
Krzysztof