Very old DTC in fresh armbian image

BrettRD · April 21, 2020

I just got a working version of the mcp251x.dts overlay running an the Allwinner H3, and ran into a few issues along the way.

I'd like to save someone the pain and maybe find the right place for a bug report for the old version of dtc in the image.

Compiling the overlay with armbian-add-overlay fails on the target system because the following throws:

dtc -@ -I dts -O dtb -o mcp251x.dtbo mcp251x.dts 
...
dtc: livetree.c:521: get_node_by_phandle: Assertion `(phandle != 0) && (phandle != -1)' failed.
aborted

The best reference I can find for this symptom is:

https://patchwork.kernel.org/patch/10015389/

Following them, commenting out the line for "interrupt-parent" allows compilation to finish, but the resulting interrupt request ends up on the wrong interrupt-controller. (gic instead of pio)

This is a bug in dtc running overlay mode, and it was patched years ago:

https://www.spinics.net/lists/devicetree/msg199958.html

My Armbian compiler build cache does not have this bug.

From the local git repo log: dtc and livetree.c in both mainline and u-boot are very much alive, maintained, and up-to-date.

This works:

./armbian/build/cache/sources/linux-mainline/orange-pi-5.4/scripts/dtc/dtc -@ -I dts -O dtb -o mcp251x.dtbo mcp251x.dts

and emits a mcp251x.dtbo that behaves nicely, and lets me send and receive packets.

Props to the Armbian team for an amazing toolchain, build from scratch and making a custom overlay was almost easy.

Where does the dtc in the image come from, and where should I send a bug report?

---

For completeness,

I still can't find documentation for the pin/port numbering for 3-cell interrupt fields in the H3 flavour of .dts.

The third field is the interrupt mode with the definitions in "include/dt-bindings/interrupt-controller/irq.h"

The second field is the pin number on a given port (0-31 inclusive)

The first number is where I got stuck for a bit, I'm pretty sure it's the port number A=0, G=6.

Not all ports have interrupts, The H3 has them on A,G, and L.
The built-in dts in the nanopiduo2 has a wake on lan on PG10 with "interrupts = <6 10 8>"

The whole mcp251x.dts went:

/dts-v1/;
/plugin/;

/ {
	compatible = "allwinner,sun8i-h3";

	fragment@0 {
		target-path = "/clocks";
		__overlay__ {
			#address-cells = <1>;
			#size-cells = <1>;
			can0_osc_fixed: can0_osc_fixed {
				compatible = "fixed-clock";
				#clock-cells = <0>;
				clock-frequency  = <8000000>;
			};
		};
	};

	fragment@1 {
		target = <&pio>;
		__overlay__ {
			can0_pin_irq: can0_pin_irq {
				pins = "PG11";
				function = "irq";
				bias-pull-up;
			};
		};
	};

	fragment@2 {
		target = <&spi1>;
		__overlay__ {
			#address-cells = <1>;
			#size-cells = <0>;
			status = "okay";
			mcp2515 {
				reg = <0>;
				compatible = "microchip,mcp2515";
				pinctrl-names = "default";
				pinctrl-0 = <&can0_pin_irq>;
				spi-max-frequency = <10000000>;
				interrupt-parent = <&pio>;
				interrupts = <6 11 2>; 
				clocks = <&can0_osc_fixed>;
				status = "okay";
			};
		};
	};
};