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Message-ID: <20240702-appease-attire-6afbe758bf0f@spud>
Date: Tue, 2 Jul 2024 16:25:06 +0100
From: Conor Dooley <conor@...nel.org>
To: Inochi Amaoto <inochiama@...look.com>
Cc: Yixun Lan <dlan@...too.org>,
Emil Renner Berthing <emil.renner.berthing@...onical.com>,
Rob Herring <robh@...nel.org>,
Krzysztof Kozlowski <krzk+dt@...nel.org>,
Conor Dooley <conor+dt@...nel.org>,
Paul Walmsley <paul.walmsley@...ive.com>,
Palmer Dabbelt <palmer@...belt.com>,
Albert Ou <aou@...s.berkeley.edu>,
Daniel Lezcano <daniel.lezcano@...aro.org>,
Thomas Gleixner <tglx@...utronix.de>,
Samuel Holland <samuel.holland@...ive.com>,
Anup Patel <anup@...infault.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Jiri Slaby <jirislaby@...nel.org>, Lubomir Rintel <lkundrak@...sk>,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
Palmer Dabbelt <palmer@...ive.com>, linux-riscv@...ts.infradead.org,
linux-serial@...r.kernel.org,
Meng Zhang <zhangmeng.kevin@...cemit.com>,
Yangyu Chen <cyy@...self.name>
Subject: Re: [PATCH v2 08/10] riscv: dts: add initial SpacemiT K1 SoC device
tree
On Tue, Jul 02, 2024 at 09:35:45AM +0800, Inochi Amaoto wrote:
> On Tue, Jul 02, 2024 at 01:28:47AM GMT, Yixun Lan wrote:
> > On 12:49 Mon 01 Jul , Emil Renner Berthing wrote:
> > > Yixun Lan wrote:
> > > > From: Yangyu Chen <cyy@...self.name>
> > > >
> > > > 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.
> > > >
> > ...
> >
> > > > + clint: timer@...00000 {
> > > > + compatible = "spacemit,k1-clint", "sifive,clint0";
> > > > + reg = <0x0 0xe4000000 0x0 0x10000>;
> > > > + interrupts-extended = <&cpu0_intc 3>, <&cpu0_intc 7>,
> > > > + <&cpu1_intc 3>, <&cpu1_intc 7>,
> > > > + <&cpu2_intc 3>, <&cpu2_intc 7>,
> > > > + <&cpu3_intc 3>, <&cpu3_intc 7>,
> > > > + <&cpu4_intc 3>, <&cpu4_intc 7>,
> > > > + <&cpu5_intc 3>, <&cpu5_intc 7>,
> > > > + <&cpu6_intc 3>, <&cpu6_intc 7>,
> > > > + <&cpu7_intc 3>, <&cpu7_intc 7>;
> > > > + };
> > > > +
> > > > + uart0: serial@...17000 {
> > > > + compatible = "spacemit,k1-uart", "intel,xscale-uart";
> > > > + reg = <0x0 0xd4017000 0x0 0x100>;
> > > > + interrupts = <42>;
> > > > + clock-frequency = <14857000>;
> > > > + reg-shift = <2>;
> > > > + reg-io-width = <4>;
> > > > + status = "disabled";
> > > > + };
> > > > +
> > > > + /* note: uart1 skipped */
> > >
> > > The datasheet page you link to above says "-UART (×10)", but here you're
> > > skipping one of them. Why? I can see the vendor tree does the same, but it
> > > would be nice with an explanation of what's going on.
> > >
> > /* note: uart1 in 0xf0612000, reserved for TEE usage */
> > I would put something like this, does this sound ok to you?
> >
> > more detail, iomem range from 0xf000,0000 - 0xf080,0000 are dedicated for TEE purpose,
> > It won't be exposed to Linux once TEE feature is enabled..
> >
> > skipping uart1 may make people confused but we are trying to follow datasheet..
>
> Instead of skipping it, I suggest adding this to reserved-memory area,
> which make all node visible and avoid uart1 being touched by mistake.
No, don't make it reserved-memory - instead add it as
status = "reserved"; /* explanation for why */
Also, I'd appreciate if the nodes were sorted by unit address in the
dtsi.
Thanks,
Conor.
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