Re: [PATCH v2 1/4] riscv: add UltraRISC SoC family Kconfig support

[Jia Wang]

On 2026-04-08 18:10 +0100, Conor Dooley wrote:
> On Wed, Apr 08, 2026 at 09:47:04AM +0800, Jia Wang wrote:
> > On 2026-04-07 17:29 +0100, Conor Dooley wrote:
> > > On Tue, Apr 07, 2026 at 10:40:52AM +0800, Jia Wang wrote:
> > > > The first SoC in the UltraRISC series is UR-DP1000, containing octa
> > > > UltraRISC C100 cores.
> > > 
> > > Not gonna lie, I find it odd that pcie is where this platform starts
> > > off, but sure. What's the plan for adding the rest of the platform?
> > >
> > 
> > Hi Conor,
> > 
> > Thanks for the question.
> > 
> > Our next step is to upstream the pinctrl driver together with the related
> > DTS updates. The pinctrl series only affects the SoC’s low-speed peripheral
> > interfaces. For GMAC, SPI, I2C, and GPIO, we plan to use the existing
> > kernel drivers, so no new controller drivers are needed 
> 
> And clocks? pinctrl and clocks would be the bare minimum level of
> support required before a platform should be merged. Obviously, you can
> get device drivers for PCI etc etc merged without clock drivers, but the
> initial dts should contain the clocks too.
>

On our platform, all functional clocks are fully configured and enabled by
the firmware before Linux boots. The kernel is not expected to adjust clock
rates or gate/ungate clocks at runtime.  
Therefore, in the initial device tree we only describe the fixed clocks
required by the standard subsystem drivers, using `fixed-clock` where needed.

Since there is no clock controller accessible to the OS, we do not plan to
add a clock driver at this stage. If future hardware versions expose a
programmable clock controller to Linux, we will upstream the corresponding
driver and update the DT accordingly.
 
> > > > 
> > > > Signed-off-by: Jia Wang <wangjia@xxxxxxxxxxxxx>
> > > > ---
> > > >  arch/riscv/Kconfig.socs | 9 +++++++++
> > > >  1 file changed, 9 insertions(+)
> > > > 
> > > > diff --git a/arch/riscv/Kconfig.socs b/arch/riscv/Kconfig.socs
> > > > index d621b85dd63b..98708569ec6a 100644
> > > > --- a/arch/riscv/Kconfig.socs
> > > > +++ b/arch/riscv/Kconfig.socs
> > > > @@ -84,6 +84,15 @@ config ARCH_THEAD
> > > >  	help
> > > >  	  This enables support for the RISC-V based T-HEAD SoCs.
> > > >  
> > > > +config ARCH_ULTRARISC
> > > > +	bool "UltraRISC RISC-V SoCs"
> > > > +	help
> > > > +	  This enables support for UltraRISC SoC platform hardware,
> > > > +	  including boards based on the UR-DP1000.
> > > 
> > > > +	  UR-DP1000 is an 8-core 64-bit RISC-V SoC that supports
> > > > +	  the RV64GCBHX ISA. It supports Hardware Virtualization
> > > > +	  and RISC-V RV64 ISA H(v1.0) Extension.
> > > 
> > > Delete this section IMO, doesn't provide any real value. Don't need nor
> > > want the marketing brochure in the help text. The first sentence is
> > > sufficient.
> > >
> > 
> > I’ll drop the SoC description part from the Kconfig help text as you
> > suggested.
> >  
> > > > +
> > > >  config ARCH_VIRT
> > > >  	bool "QEMU Virt Machine"
> > > >  	select POWER_RESET
> > > > 
> > > > -- 
> > > > 2.34.1
> > > > 
> > 
> > Best regards,
> > Jia Wang
> >