Re: [PATCH v2] dts: arm64: add CoreSight trace support for hi3660

On Sat, Mar 02, 2019 at 09:45:22AM +0000, Shiwanglai wrote:

[...]

...

• /* Top internals */
  

• funnel@ec031000 {
  

• 	compatible = "arm,coresight-funnel", "arm,primecell";
  

• 	reg = <0 0xec031000 0 0x1000>;
  

• 	clocks = <&crg_ctrl HI3660_PCLK>;
  

• 	clock-names = "apb_pclk";
  

• 	out-ports {
  

• 		port {
  

• 			top_funnel_out: endpoint {
  

• 				remote-endpoint =
  

• 					<&top_etf_in>;
  

• 			};
  

• 		};
  

• 	};
  

• 	in-ports {
  

• 		#address-cells = <1>;
  

• 		#size-cells = <0>;
  

• 		port@0 {
  

• 			reg = <0>;
  

• 			top_funnel_in0: endpoint {
  

• 				remote-endpoint =
  

• 					<&cluster0_etf_out>;
  

• 			};
  

• 		};
  

• 		port@1 {
  

• 			reg = <0>;
  

Here should s/<0>/<1>; otherwise DTC will complain warning for mismatching between 'port@1' and 'reg = <0>'.

-- if reg set to 1, then there's no data output from cluster 1 to top.

Thanks for the info, Wanglai. Now I see why write as it is.

I can confirm if directly use your patch with perf with mainline kernel I can capture CoreSight trace data successfully on Hikey960 board.

But since this DT binding will introduce DTC warning, I personally think we can improve for this with below method:

We can create a funnel node named "funnel_combo", and we don't need to specify register address range for it; and cluster 0 and cluster 1 will output to "funnel_combo" and "funnel_combo" will output to the top funnel. Thus the DT binding will write as below.

To support for a funnel without any register address range (we have support replicator like this mode), we also need to extend the driver drivers/hwtracing/coresight/coresight-funnel.c.

Mathieu, Mike, Suzuki, could you help confirm this is the right direction we should move forward to?

---8<--- /* An invisible combo funnel between clusters and top funnel */ funnel_combo { compatible = "arm,coresight-funnel"; clocks = <&crg_ctrl HI3660_PCLK>; clock-names = "apb_pclk";

out-ports { port { combo_funnel_out: endpoint { remote-endpoint = <&top_funnel_in>; }; }; };

in-ports { #address-cells = <1>; #size-cells = <0>;

port@0 { reg = <0>; combo_funnel_in0: endpoint { remote-endpoint = <&cluster0_etf_out>; }; };

port@1 { reg = <1>; combo_funnel_in1: endpoint { remote-endpoint = <&cluster1_etf_out>; }; }; }; };

/* Top internals */ funnel@ec031000 { compatible = "arm,coresight-funnel", "arm,primecell"; reg = <0 0xec031000 0 0x1000>; clocks = <&crg_ctrl HI3660_PCLK>; clock-names = "apb_pclk";

out-ports { port { top_funnel_out: endpoint { remote-endpoint = <&top_etf_in>; }; }; };

in-ports { #address-cells = <1>; #size-cells = <0>;

port@0 { reg = <0>; top_funnel_in: endpoint { remote-endpoint = <&combo_funnel_out>; }; }; }; };

--->8---

[...]

Thanks, Leo Yan