Re: [RFT PATCH v1 2/4] dt-binding: cpu-topology: Move cpu-map to a common binding.
From: Atish Patra
Date: Mon Dec 03 2018 - 12:40:26 EST
On 12/3/18 9:33 AM, Sudeep Holla wrote:
On Mon, Dec 03, 2018 at 09:23:42AM -0800, Atish Patra wrote:
On 12/3/18 8:55 AM, Sudeep Holla wrote:
On Thu, Nov 29, 2018 at 03:28:18PM -0800, Atish Patra wrote:
cpu-map binding can be used to described cpu topology for both
RISC-V & ARM. It makes more sense to move the binding to document
to a common place.
The relevant discussion can be found here.
https://lkml.org/lkml/2018/11/6/19
Looks good to me apart from a minor query below in the example.
Reviewed-by: Sudeep Holla <sudeep.holla@xxxxxxx>
Signed-off-by: Atish Patra <atish.patra@xxxxxxx>
---
.../{arm/topology.txt => cpu/cpu-topology.txt} | 81 ++++++++++++++++++----
1 file changed, 67 insertions(+), 14 deletions(-)
rename Documentation/devicetree/bindings/{arm/topology.txt => cpu/cpu-topology.txt} (86%)
diff --git a/Documentation/devicetree/bindings/arm/topology.txt b/Documentation/devicetree/bindings/cpu/cpu-topology.txt
similarity index 86%
rename from Documentation/devicetree/bindings/arm/topology.txt
rename to Documentation/devicetree/bindings/cpu/cpu-topology.txt
index 66848355..1de6fbce 100644
--- a/Documentation/devicetree/bindings/arm/topology.txt
+++ b/Documentation/devicetree/bindings/cpu/cpu-topology.txt
[...]
+Example 3: HiFive Unleashed (RISC-V 64 bit, 4 core system)
+
+cpus {
+ #address-cells = <2>;
+ #size-cells = <2>;
+ compatible = "sifive,fu540g", "sifive,fu500";
+ model = "sifive,hifive-unleashed-a00";
+
+ ...
+
+ cpu-map {
+ cluster0 {
+ core0 {
+ cpu = <&L12>;
+ };
+ core1 {
+ cpu = <&L15>;
+ };
+ core2 {
+ cpu0 = <&L18>;
+ };
+ core3 {
+ cpu0 = <&L21>;
+ };
+ };
+ };
+
+ L12: cpu@1 {
+ device_type = "cpu";
+ compatible = "sifive,rocket0", "riscv";
+ reg = <0x1>;
+ }
+
+ L15: cpu@2 {
+ device_type = "cpu";
+ compatible = "sifive,rocket0", "riscv";
+ reg = <0x2>;
+ }
+ L18: cpu@3 {
+ device_type = "cpu";
+ compatible = "sifive,rocket0", "riscv";
+ reg = <0x3>;
+ }
+ L21: cpu@4 {
+ device_type = "cpu";
+ compatible = "sifive,rocket0", "riscv";
+ reg = <0x4>;
+ }
+};
The labels for the CPUs drew my attention. Is it intentionally random
(or even specific) or just chosen to show anything can be used as labels ?
SiFive generates the device tree from RTL directly. So I am not sure if they
assign random numbers or a particular algorithm chooses the label. I tried
to put the exact ones that is available publicly.
https://github.com/riscv/riscv-device-tree-doc/blob/master/examples/sifive-hifive_unleashed-microsemi.dts
Cool, love that. So you don't have the problem I was trying to explain.
But I still see the possibility of some other RISC-V vendor copy-pasting
from here ;). Anyways it's left to you.
I am fine with either way. I hoped other vendors won't blindly copy as
this example was specific to HiFive Unleashed board. But I get your
point. As this DT entry is a generic architecture entry, we should have
generic examples instead of platform specific examples.
I will change it to a generic one.
Regards,
Atish
--
Regards,
Sudeep