Re: [PATCH v1 7/9] riscv: dts: add initial SpacemiT K1 SoC device tree

From: Jisheng Zhang <jszhang@kernel.org>
To: Conor Dooley <conor.dooley@microchip.com>
Cc: Yangyu Chen <cyy@cyyself.name>,
	linux-riscv@lists.infradead.org,
	Conor Dooley <conor+dt@kernel.org>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Samuel Holland <samuel.holland@sifive.com>,
	Anup Patel <anup.patel@wdc.com>, Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v1 7/9] riscv: dts: add initial SpacemiT K1 SoC device tree
Date: Mon, 17 Jun 2024 21:31:17 +0800	[thread overview]
Message-ID: <ZnA6pZLkI2StP8Hh@xhacker> (raw)
In-Reply-To: <20240617-carat-poise-ee63ed6a224e@wendy>

On Mon, Jun 17, 2024 at 02:29:46PM +0100, Conor Dooley wrote:
> On Mon, Jun 17, 2024 at 08:49:57PM +0800, Jisheng Zhang wrote:
> > On Mon, Jun 17, 2024 at 01:20:52AM +0800, Yangyu Chen wrote:
> > > Banana Pi BPI-F3 motherboard is powered by SpacemiT K1[1].
> > > 
> > > Key features:
> > > - 4 cores per cluster, 2 clusters on chip
> > > - UART IP is Intel XScale UART
> > > 
> > > Some key considerations:
> > > - ISA string is inferred from vendor documentation[2]
> > > - Cluster topology is inferred from datasheet[1] and L2 in vendor dts[3]
> > > - No coherent DMA on this board
> > >     Inferred by taking vendor ethernet and MMC drivers to the mainline
> > >     kernel. Without dma-noncoherent in soc node, the driver fails.
> > > - No cache nodes now
> > >     The parameters from vendor dts are likely to be wrong. It has 512
> > >     sets for a 32KiB L1 Cache. In this case, each set is 64B in size.
> > >     When the size of the cache line is 64B, it is a directly mapped
> > >     cache rather than a set-associative cache, the latter is commonly
> > >     used. Thus, I didn't use the parameters from vendor dts.
> > > 
> > > Currently only support booting into console with only uart, other
> > > features will be added soon later.
> > 
> > Hi Yangyu,
> > 
> > Per recent practice of cv1800b and th1520 upstream, I think a complete
> > initial support would include pinctrl, clk and reset, I have received
> > the complains from the community. So can you please bring the pinctrl
> > clk  and reset at the same time?
> 
> What sort of complaints have you got? That the support is too minimal to
> be useful?

For example https://lore.kernel.org/linux-riscv/95c20c6c-66cd-4f87-920b-5da766317e19@sifive.com/

Now, I think it's better to "model the clocks/resets/other dependencies"
in the initial support. So lacking of pinctrl, clk and reset doesn't
fully describe the hardware.

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