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Date:   Tue, 22 Feb 2022 08:56:42 -0800 (PST)
Subject:     Re: [PATCH 00/12] Initial support for Nuclei DemoSoC w/ UX600
In-Reply-To: <6ff70d9fbbfcde860823aa24f0ce58a0a96a1c91.camel@nucleisys.com>
CC:     Paul Walmsley <paul.walmsley@sifive.com>, aou@eecs.berkeley.edu,
        linux-kernel@vger.kernel.org, devicetree@vger.kernel.org,
        linux-riscv@lists.infradead.org, linux-serial@vger.kernel.org,
        linux-spi@vger.kernel.org
From:   Palmer Dabbelt <palmer@dabbelt.com>
To:     icenowy@nucleisys.com, robh+dt@kernel.org
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On Sat, 19 Feb 2022 06:45:43 PST (-0800), icenowy@nucleisys.com wrote:
> 在 2022-01-27星期四的 23:16 +0800，Icenowy Zheng写道：
>> This patchset adds support for Nuclei DemoSoC (which is an evaluation
>> platform made with Nuclei CPU cores and mainly peripherals in
>> original
>> Hummingbird E203 project, running on FPGA) with UX600 CPU cores.
>>
>> Most patches are for DT bindings, the remaining ones are adding a
>> Kconfig option and some DTS/DTSI files. The last one is a workaround
>> for
>> a severe bug in currently released versions of UX600, which is found
>> in 5.17 kernel, in which Sv48 support is added to Linux.
>>
>> Two non-technical patches are in this patchset too, for MAINTAINERS
>> and .mailmap items.
>
> Ping, could any RISC-V maintainers review these patches, especially the
> SATP workaround one?

Sorry, I remember having written this but I guess it got lost.  IIRC my 
main worry here was that, at least as far as I can tell, DemoSOC is an 
FPGA development board.  If this is actually in production somewhere 
then it's a different story, but IIUC the general rule is not to accept 
code for development hardware that can be updated.

Assuming DemoSOC can be updated, I'd also argue that we should have some 
sort of version attached to it in DT entries.  Without some versioning 
we'll end up lost when trying to later determine what we're actually 
running on.

As far as the errata goes: it looks fine to me, but I'd like to see some 
sort of description of what the errata actually is (ie, some 
documentation from the manufacturer).  I know that's not always 
possible, but without some desciption of what the bug is it gets tricky 
to mainain this sort of stuff.  For example: we've got sv57 patches 
now, so how do I know what to do with them on this target?

>
>>
>> Icenowy Zheng (12):
>>   dt-bindings: vendor-prefixes: add Nuclei
>>   RISC-V: add Nuclei SoC Kconfig option
>>   dt-bindings: riscv: add compatible strings for Nuclei UX600 series
>>   dt-bindings: timer: add compatible for Nuclei UX600 CLINT-compat
>> timer
>>   dt-bindings: interrupt-controller: add compatible string for UX600
>>     PLIC
>>   dt-bindings: serial: add compatible string for Nuclei DemoSoC UART
>>   dt-bindings: spi: add compatible string for Nuclei DemoSoC SPI
>>   dt-bindings: riscv: add binding for Nuclei platform boards
>>   riscv: dts: add device tree for Nuclei DemoSoC w/ UX600 on DDR200T
>>   RISC-V: workaround Nuclei UX600 cores with broken SATP CSR
>>   MAINTAINERS: add myself as Nuclei SoCs/CPUs supporter
>>   mailmap: add Icenowy Zheng's Nuclei mail addresses
>>
>>  .mailmap                                      |  1 +
>>  .../sifive,plic-1.0.0.yaml                    |  1 +
>>  .../devicetree/bindings/riscv/cpus.yaml       |  7 ++
>>  .../devicetree/bindings/riscv/nuclei.yaml     | 27 ++++++++
>>  .../bindings/serial/sifive-serial.yaml        |  1 +
>>  .../devicetree/bindings/spi/spi-sifive.yaml   |  1 +
>>  .../bindings/timer/sifive,clint.yaml          |  1 +
>>  .../devicetree/bindings/vendor-prefixes.yaml  |  2 +
>>  MAINTAINERS                                   |  7 ++
>>  arch/riscv/Kconfig.socs                       |  6 ++
>>  arch/riscv/boot/dts/Makefile                  |  1 +
>>  arch/riscv/boot/dts/nuclei/Makefile           |  2 +
>>  .../dts/nuclei/nuclei-demosoc-ddr200t.dtsi    | 41 ++++++++++++
>>  .../nuclei/nuclei-demosoc-ux600-ddr200t.dts   | 13 ++++
>>  .../boot/dts/nuclei/nuclei-demosoc-ux600.dtsi | 49 ++++++++++++++
>>  .../riscv/boot/dts/nuclei/nuclei-demosoc.dtsi | 67
>> +++++++++++++++++++
>>  arch/riscv/include/asm/vendorid_list.h        |  1 +
>>  arch/riscv/mm/init.c                          | 17 +++++
>>  18 files changed, 245 insertions(+)
>>  create mode 100644
>> Documentation/devicetree/bindings/riscv/nuclei.yaml
>>  create mode 100644 arch/riscv/boot/dts/nuclei/Makefile
>>  create mode 100644 arch/riscv/boot/dts/nuclei/nuclei-demosoc-
>> ddr200t.dtsi
>>  create mode 100644 arch/riscv/boot/dts/nuclei/nuclei-demosoc-ux600-
>> ddr200t.dts
>>  create mode 100644 arch/riscv/boot/dts/nuclei/nuclei-demosoc-
>> ux600.dtsi
>>  create mode 100644 arch/riscv/boot/dts/nuclei/nuclei-demosoc.dtsi
>>