diff mbox series

[v2,5/5] dt-bindings: timer: Add CLINT bindings

Message ID 20200627161957.134376-6-anup.patel@wdc.com
State Changes Requested
Headers show
Series Dedicated CLINT timer driver | expand

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Context Check Description
robh/checkpatch warning total: 0 errors, 1 warnings, 34 lines checked

Commit Message

Anup Patel June 27, 2020, 4:19 p.m. UTC
We add DT bindings documentation for CLINT device.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
---
 .../bindings/timer/sifive,clint.txt           | 34 +++++++++++++++++++
 1 file changed, 34 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/timer/sifive,clint.txt

Comments

Rob Herring July 14, 2020, 2:37 a.m. UTC | #1
On Sat, Jun 27, 2020 at 09:49:57PM +0530, Anup Patel wrote:
> We add DT bindings documentation for CLINT device.
> 
> Signed-off-by: Anup Patel <anup.patel@wdc.com>
> Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
> ---
>  .../bindings/timer/sifive,clint.txt           | 34 +++++++++++++++++++
>  1 file changed, 34 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/timer/sifive,clint.txt

Bindings should be in DT schema format now.

> 
> diff --git a/Documentation/devicetree/bindings/timer/sifive,clint.txt b/Documentation/devicetree/bindings/timer/sifive,clint.txt
> new file mode 100644
> index 000000000000..45b75347a7d5
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/timer/sifive,clint.txt
> @@ -0,0 +1,34 @@
> +SiFive Core Local Interruptor (CLINT)
> +-------------------------------------
> +
> +SiFive (and other RISC-V) SOCs include an implementation of the SiFive Core
> +Local Interruptor (CLINT) for M-mode timer and inter-processor interrupts.
> +
> +It directly connects to the timer and inter-processor interrupt lines of
> +various HARTs (or CPUs) so RISC-V per-HART (or per-CPU) local interrupt
> +controller is the parent interrupt controller for CLINT device.
> +
> +The clock frequency of CLINT is specified via "timebase-frequency" DT
> +property of "/cpus" DT node. The "timebase-frequency" DT property is
> +described in: Documentation/devicetree/bindings/riscv/cpus.yaml
> +
> +Required properties:
> +- compatible : should be "riscv,clint0" or "sifive,clint-1.0.0". A specific

A new versioning scheme from SiFive? To review, we don't do version 
numbers unless there's a well defined and documented scheme. IOW, one 
that's not s/w folks just making up v1, v2, v3, etc.

> +  string identifying the actual implementation can be added if implementation
> +  specific worked arounds are needed.
> +- reg : Should contain 1 register range (address and length).
> +- interrupts-extended : Specifies which HARTs (or CPUs) are connected to
> +  the CLINT.  Each node pointed to should be a riscv,cpu-intc node, which
> +  has a riscv node as parent.
> +
> +Example:
> +
> +	clint@2000000 {
> +		compatible = "sifive,clint-1.0.0", "sifive,fu540-c000-clint";

Doesn't match the binding.

> +		interrupts-extended = <
> +			&cpu1-intc 3 &cpu1-intc 7
> +			&cpu2-intc 3 &cpu2-intc 7
> +			&cpu3-intc 3 &cpu3-intc 7
> +			&cpu4-intc 3 &cpu4-intc 7>;
> +		reg = <0x2000000 0x4000000>;
> +	};
> -- 
> 2.25.1
>
Anup Patel July 14, 2020, 3:47 a.m. UTC | #2
On Tue, Jul 14, 2020 at 8:07 AM Rob Herring <robh@kernel.org> wrote:
>
> On Sat, Jun 27, 2020 at 09:49:57PM +0530, Anup Patel wrote:
> > We add DT bindings documentation for CLINT device.
> >
> > Signed-off-by: Anup Patel <anup.patel@wdc.com>
> > Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
> > ---
> >  .../bindings/timer/sifive,clint.txt           | 34 +++++++++++++++++++
> >  1 file changed, 34 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/timer/sifive,clint.txt
>
> Bindings should be in DT schema format now.

Okay, will update.

>
> >
> > diff --git a/Documentation/devicetree/bindings/timer/sifive,clint.txt b/Documentation/devicetree/bindings/timer/sifive,clint.txt
> > new file mode 100644
> > index 000000000000..45b75347a7d5
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/timer/sifive,clint.txt
> > @@ -0,0 +1,34 @@
> > +SiFive Core Local Interruptor (CLINT)
> > +-------------------------------------
> > +
> > +SiFive (and other RISC-V) SOCs include an implementation of the SiFive Core
> > +Local Interruptor (CLINT) for M-mode timer and inter-processor interrupts.
> > +
> > +It directly connects to the timer and inter-processor interrupt lines of
> > +various HARTs (or CPUs) so RISC-V per-HART (or per-CPU) local interrupt
> > +controller is the parent interrupt controller for CLINT device.
> > +
> > +The clock frequency of CLINT is specified via "timebase-frequency" DT
> > +property of "/cpus" DT node. The "timebase-frequency" DT property is
> > +described in: Documentation/devicetree/bindings/riscv/cpus.yaml
> > +
> > +Required properties:
> > +- compatible : should be "riscv,clint0" or "sifive,clint-1.0.0". A specific
>
> A new versioning scheme from SiFive? To review, we don't do version
> numbers unless there's a well defined and documented scheme. IOW, one
> that's not s/w folks just making up v1, v2, v3, etc.

The "riscv,clint0" is already used by various RISC-V systems (including QEMU).

The "sifive,clint-1.0.0" is for being consistent with the PLIC
versioning scheme.

There is no clear documentation of CLINT versioning scheme. I think it's best
to just drop "sifive,clint-1.0.0" . Agree ??

>
> > +  string identifying the actual implementation can be added if implementation
> > +  specific worked arounds are needed.
> > +- reg : Should contain 1 register range (address and length).
> > +- interrupts-extended : Specifies which HARTs (or CPUs) are connected to
> > +  the CLINT.  Each node pointed to should be a riscv,cpu-intc node, which
> > +  has a riscv node as parent.
> > +
> > +Example:
> > +
> > +     clint@2000000 {
> > +             compatible = "sifive,clint-1.0.0", "sifive,fu540-c000-clint";
>
> Doesn't match the binding.

Okay, will update.

>
> > +             interrupts-extended = <
> > +                     &cpu1-intc 3 &cpu1-intc 7
> > +                     &cpu2-intc 3 &cpu2-intc 7
> > +                     &cpu3-intc 3 &cpu3-intc 7
> > +                     &cpu4-intc 3 &cpu4-intc 7>;
> > +             reg = <0x2000000 0x4000000>;
> > +     };
> > --
> > 2.25.1
> >

Regards,
Anup
Rob Herring July 14, 2020, 3:04 p.m. UTC | #3
On Mon, Jul 13, 2020 at 9:47 PM Anup Patel <anup@brainfault.org> wrote:
>
> On Tue, Jul 14, 2020 at 8:07 AM Rob Herring <robh@kernel.org> wrote:
> >
> > On Sat, Jun 27, 2020 at 09:49:57PM +0530, Anup Patel wrote:
> > > We add DT bindings documentation for CLINT device.
> > >
> > > Signed-off-by: Anup Patel <anup.patel@wdc.com>
> > > Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
> > > ---
> > >  .../bindings/timer/sifive,clint.txt           | 34 +++++++++++++++++++
> > >  1 file changed, 34 insertions(+)
> > >  create mode 100644 Documentation/devicetree/bindings/timer/sifive,clint.txt
> >
> > Bindings should be in DT schema format now.
>
> Okay, will update.
>
> >
> > >
> > > diff --git a/Documentation/devicetree/bindings/timer/sifive,clint.txt b/Documentation/devicetree/bindings/timer/sifive,clint.txt
> > > new file mode 100644
> > > index 000000000000..45b75347a7d5
> > > --- /dev/null
> > > +++ b/Documentation/devicetree/bindings/timer/sifive,clint.txt
> > > @@ -0,0 +1,34 @@
> > > +SiFive Core Local Interruptor (CLINT)
> > > +-------------------------------------
> > > +
> > > +SiFive (and other RISC-V) SOCs include an implementation of the SiFive Core
> > > +Local Interruptor (CLINT) for M-mode timer and inter-processor interrupts.
> > > +
> > > +It directly connects to the timer and inter-processor interrupt lines of
> > > +various HARTs (or CPUs) so RISC-V per-HART (or per-CPU) local interrupt
> > > +controller is the parent interrupt controller for CLINT device.
> > > +
> > > +The clock frequency of CLINT is specified via "timebase-frequency" DT
> > > +property of "/cpus" DT node. The "timebase-frequency" DT property is
> > > +described in: Documentation/devicetree/bindings/riscv/cpus.yaml
> > > +
> > > +Required properties:
> > > +- compatible : should be "riscv,clint0" or "sifive,clint-1.0.0". A specific
> >
> > A new versioning scheme from SiFive? To review, we don't do version
> > numbers unless there's a well defined and documented scheme. IOW, one
> > that's not s/w folks just making up v1, v2, v3, etc.
>
> The "riscv,clint0" is already used by various RISC-V systems (including QEMU).

Not my problem that undocumented bindings are being used.

> The "sifive,clint-1.0.0" is for being consistent with the PLIC
> versioning scheme.

Where is that documented? This is what I expect you to be following or
updating to match:

Documentation/devicetree/bindings/sifive/sifive-blocks-ip-versioning.txt

>
> There is no clear documentation of CLINT versioning scheme. I think it's best
> to just drop "sifive,clint-1.0.0" . Agree ??

No, because then you are left with a very generic compatible string.
You need something specific enough to handle any implementation
features/quirks/bugs without needing a DT update. Typically, this
means a per SoC compatible string for a block as even the same IP
version can have different integration quirks.

Rob
diff mbox series

Patch

diff --git a/Documentation/devicetree/bindings/timer/sifive,clint.txt b/Documentation/devicetree/bindings/timer/sifive,clint.txt
new file mode 100644
index 000000000000..45b75347a7d5
--- /dev/null
+++ b/Documentation/devicetree/bindings/timer/sifive,clint.txt
@@ -0,0 +1,34 @@ 
+SiFive Core Local Interruptor (CLINT)
+-------------------------------------
+
+SiFive (and other RISC-V) SOCs include an implementation of the SiFive Core
+Local Interruptor (CLINT) for M-mode timer and inter-processor interrupts.
+
+It directly connects to the timer and inter-processor interrupt lines of
+various HARTs (or CPUs) so RISC-V per-HART (or per-CPU) local interrupt
+controller is the parent interrupt controller for CLINT device.
+
+The clock frequency of CLINT is specified via "timebase-frequency" DT
+property of "/cpus" DT node. The "timebase-frequency" DT property is
+described in: Documentation/devicetree/bindings/riscv/cpus.yaml
+
+Required properties:
+- compatible : should be "riscv,clint0" or "sifive,clint-1.0.0". A specific
+  string identifying the actual implementation can be added if implementation
+  specific worked arounds are needed.
+- reg : Should contain 1 register range (address and length).
+- interrupts-extended : Specifies which HARTs (or CPUs) are connected to
+  the CLINT.  Each node pointed to should be a riscv,cpu-intc node, which
+  has a riscv node as parent.
+
+Example:
+
+	clint@2000000 {
+		compatible = "sifive,clint-1.0.0", "sifive,fu540-c000-clint";
+		interrupts-extended = <
+			&cpu1-intc 3 &cpu1-intc 7
+			&cpu2-intc 3 &cpu2-intc 7
+			&cpu3-intc 3 &cpu3-intc 7
+			&cpu4-intc 3 &cpu4-intc 7>;
+		reg = <0x2000000 0x4000000>;
+	};