UARTA / UARTC dtbo not loading (FDT_ERR_NOTFOUND/ FDT_ERR_BADMAGIC)

[Vicentiu Ciorbaru]

Hi!

 

Using the vanilla ARMBIAN image 23.02.2_Bananapim5_bullseye_current_6.1.11_minimal

Enabling the provided uartA and uartC dtbos fails.

Here is the output from the boot process, as captured via the Serial Debug interface:

 

238 bytes read in 3 ms (77.1 KiB/s)
Applying kernel provided DT overlay meson-uartA.dtbo
failed on fdt_overlay_apply(): FDT_ERR_NOTFOUND
238 bytes read in 3 ms (77.1 KiB/s)
Applying kernel provided DT overlay meson-uartC.dtbo
failed on fdt_overlay_apply(): FDT_ERR_BADMAGIC

 

It seems that this image provides invalid dtbos, likely not properly built alongside the same kernel image.

 

I'm happy to help debug this as I have a system at the ready.

[Vicentiu Ciorbaru]

After decompiling the meson-uartA.dtbo, it seems like the addresses are wrong:

 

/dts-v1/;

/ {
	compatible = "amlogic,meson-gxbb";

	fragment@0 {
		target-path = "/soc/bus@c1100000/serial@84c0";

		__overlay__ {
			status = "okay";
		};
	};
};

Looking at the CPUs datasheet https://dn.odroid.com/S905X3/ODROID-C4/Docs/S905X3_Public_Datasheet_Hardkernel.pdf, the memory map is:

Start    End      Peripheral
FFD24000 FFD24FFF uart0
FFD23000 FFD23FFF uart1
FFD22000 FFD22FFF uart2

 

Thus, I have changed the DTS like so:

 

/dts-v1/;

/ {
	compatible = "amlogic,sm1";

	fragment@0 {
		target-path = "/aliases";

		__overlay__ {
			serial1 = "/soc/bus@ffd00000/serial@24000";
		};
	};

	fragment@1 {
		target-path = "/soc/bus@ffd00000/serial@24000";

		__overlay__ {
			status = "okay";
		};
	};
};

 

This DTS is the one used by Sinovo's Armbian release and now I have two devices /dev/ttyAML0 and /dev/ttyAML1

 

I suspect that none of the "enablea-ble" DTBs from armbian-config are actually functional. Additionally, armbian doesn't come with SPI dtbo overlay in order to enable the HW. I recommend for the maintainers to add that to the images. If there is a guide for how to do this, I might be able to give it a shot to update it myself.

Edited April 10, 2023 by Vicentiu Ciorbaru

[Vicentiu Ciorbaru]

After further debugging, the DTS from above is not enough. Crosschecking between Armbian's banana-pi-m5.dtb and the one provided by Sinovo's Armbian, I noticed the following change in "serial@24000" node.

 

-                               phandle = <0x128>;
+                               pinctrl-0 = <0x27 0x28>;
+                               pinctrl-names = "default";
+                               uart-has-rtscts;
+                               phandle = <0x12a>;

 

 

I'm not an expert in DTS definitions, but as far as I understand, the phandle is a reference. The reference doesn't seem to be used anywhere in the main DTS, so I haven't changed it.

Instead I've modified the overlay to add the other changes:

 

/dts-v1/;

/ {
	compatible = "amlogic,sm1";

	fragment@0 {
		target-path = "/aliases";

		__overlay__ {
			serial1 = "/soc/bus@ffd00000/serial@24000";
		};
	};

	fragment@1 {
		target-path = "/soc/bus@ffd00000/serial@24000";

		__overlay__ {
			pinctrl-0 = <0x27 0x28>;
			pinctrl-names = "default";
			uart-has-rtscts;
			status = "okay";
		};
	};
};

 

 

I confirm that after these changes, UART finally works. Hope this helps anyone in search of a solution. I hope the Armbian maintainers can address these problems related to the Banana Pi M5 board.

 

 

EDIT:

After reverting the previous DTS, as I pasted in the previous post and doing a full power cycle, the UART works still. So it's likely that I didn't power cycle the board properly. I just kept pressing the reset button, but that doesn't seem to be enough apparently?

Edited April 10, 2023 by Vicentiu Ciorbaru

[PikaBZH]

I had the same problem, I had to grope a bit, knowing nothing about dt overlays.

 

Here are the ones I came up with, if they can be useful to anyone as a temp fix at least.

I've not bothered with the UARTs RTS/CTS, having no use for them, and these might break on kernel upgrade when the pinctrl phandles change.

 

UART#1 -> U1F : UART_EE_A = GPIO pins 8(TX),10(RX)

/dts-v1/;

/ {
	compatible = "amlogic,meson-gxbb";

	fragment@0 {
		target-path = "/aliases";

		__overlay__ {
			serial1 = "/soc/bus@ffd00000/serial@24000";
		};
	};

	fragment@1 {
		target-path = "/soc/bus@ffd00000/serial@24000";

		__overlay__ {
			pinctrl-0 = <0xdc 0xdd>;
			pinctrl-names = "default";
			status = "okay";
		};
	};
};

 

UART#2 ->  U1F : UART_EE_B = GPIO pins 33(TX), 15(RX)

/dts-v1/;

/ {
	compatible = "amlogic,meson-gxbb";

	fragment@0 {
		target-path = "/aliases";

		__overlay__ {
			serial2 = "/soc/bus@ffd00000/serial@23000";
		};
	};

	fragment@1 {
		target-path = "/soc/bus@ffd00000/serial@23000";

		__overlay__ {
			pinctrl-0 = <0xde>;
			pinctrl-names = "default";
			status = "okay";
		};
	};
};

 

UART#4 ->  U1A : UART_AO_B = GPIO pins 12(TX), 37(RX)

/dts-v1/;

/ {
	compatible = "amlogic,meson-gxbb";

	fragment@0 {
		target-path = "/aliases";

		__overlay__ {
			serial4 = "/soc/bus@ff800000/serial@4000";
		};
	};

	fragment@1 {
		target-path = "/soc/bus@ff800000/serial@4000";

		__overlay__ {
			pinctrl-0 = <0x103>;
			pinctrl-names = "default";
			status = "okay";
		};
	};
};

 

I2C_EE_M2 = GPIO pins 3(SDA), 5(SCL)

/dts-v1/;

/ {
	compatible = "amlogic,meson-gxbb";

	fragment@0 {
		target-path = "/aliases";

		__overlay__ {
			i2c0 = "/soc/bus@ffd00000/i2c@1d000";
		};
	};

	fragment@1 {
		target-path = "/soc/bus@ffd00000/i2c@1d000";

		__overlay__ {
			pinctrl-0 = <0x6f 0x70>;
			pinctrl-names = "default";
			status = "okay";
		};
	};
};