Linux/AM4376: prueth did't work on custom board

First of all, thanks for your reply.

Yes, of course I've seen this threads. Unfortunately, they do not contain the answers for me.
First thread stopped at "prueth pruss_eth: netdev init ethernet-mii1 failed: -19". Which seen as the same problem as mine but thread stopped and therefore it couldn' know whether to solve the problem.
Second thread stopped at "The pr2_mii1_txd0 ~ pr2_mii1_txd3 pin can not detect any level changing. It always low level. " So there also no answer.
Third thread about DT without property compatible with "IDK-EVM" board = isn't our case.
Fourth thread has status "Answered" but also not interesting for me - there was a problem in the wrong path for the firmware.

So, none of this thread did not help me.

I think the question should be divided into two:
1) Software defect
2) Hardware defect

Given the amount of researched information, I have tried almost everything that could be found on the forum. But something that is left)))
To my great regret, I personally do not have access to AM437X-IDK-EVM (only SK-EVM, GP-EVM we have) and I can't compare the signals, kernel logs, etc IDK board with our custom board.

So, please help me. First, we assume that the problem is in the software part

1) Where can I see that the ethernet firmware is successfully loaded into the PRU and ready to work?
2) What are the possible problems with IRQ, DMA? Is it enough terms that stated in file "am4372.dtsi"
3) What is the possible problem of the loading prueth driver before pru_rproc? And how it fixit?

Thanks again for your reply and especially for reminding me of the list "Knowing issues".

But back to the ethernet
1) Yes, we know what TI do not provide the source code for the PRU Ethernet firmwares.
2) Diff between our custom board and AM437x IDK
- we don't use CPSW and kernel config options didn't contain TI CPSW options
- Davinci MDIO build in kernel, remoteproc, prueth as modules
- we have 1 PRU Ethernet port connected to PHY TLK105L which has default address 0x01
- pin mux setup:

PRUSS MDIO
C24 pr1_mdio_mdclk
D24 pr1_mdio_data
GPIO5[12] used as pin for reset PHY

at DT described as

pruss1_mdio_default: pruss1_mdio_default {
		pinctrl-single,pins = <
			0x274 ( PIN_OUTPUT        | MUX_MODE8 ) 	/* (C24) xdma_event_intr1.pr1_mdio_mdclk */
			0x270 ( PIN_INPUT_PULLUP  | MUX_MODE8 )	/* (D24) xdma_event_intr0.pr1_mdio_data */
			0x248 ( PIN_INPUT_PULLUP  | MUX_MODE7 )	/* (E25) gpio5_12.gpio5[12] */
		>;
	};

&pruss1_mdio {
	pinctrl-0 = <&pruss1_mdio_default>;
	pinctrl-names = "default";
	status = "okay";

	reset-gpios = <&gpio5 12 GPIO_ACTIVE_LOW>;
	reset-delay-us = <2>;	/* PHY datasheet states 1uS min */

	pruss1_eth0_phy: ethernet-phy@0 {
		compatible = "ethernet-phy-id2000.a210";
		reg = <1>;
	};
};

PRU Ethernet port
B22 pr1_mii_mt0_clk
A21 pr1_mii0_txen
B20 pr1_mii0_txd0
A20 pr1_mii0_txd1
C21 pr1_mii0_txd2
B21 pr1_mii0_txd3
C17 pr1_mii_mr0_clk
D17 pr1_mii0_rxdv
D19 pr1_mii0_rxer
B18 pr1_mii0_rxd0
A18 pr1_mii0_rxd1
B19 pr1_mii0_rxd2
A19 pr1_mii0_rxd3
G20 pr1_mii0_crs
D25 pr1_mii0_col
C19 pr1_mii0_rxlink

at DT described as

	pruss1_eth_default: pruss1_eth_default {
		pinctrl-single,pins = <
			0xa0  ( PIN_INPUT  | MUX_MODE2 ) /* (B22) dss_data0.pr1_mii_mt0_clk */
			0xb4  ( PIN_OUTPUT | MUX_MODE2 ) /* (B20) dss_data5.pr1_mii0_txd0 */
			0xb0  ( PIN_OUTPUT | MUX_MODE2 ) /* (A20) dss_data4.pr1_mii0_txd1 */
			0xac  ( PIN_OUTPUT | MUX_MODE2 ) /* (C21) dss_data3.pr1_mii0_txd2 */
			0xa8  ( PIN_OUTPUT | MUX_MODE2 ) /* (B21) dss_data2.pr1_mii0_txd3 */
			0xcc  ( PIN_INPUT  | MUX_MODE5 ) /* (B18) dss_data11.pr1_mii0_rxd0 */
			0xc8  ( PIN_INPUT  | MUX_MODE5 ) /* (A18) dss_data10.pr1_mii0_rxd1 */
			0xc4  ( PIN_INPUT  | MUX_MODE5 ) /* (B19) dss_data9.pr1_mii0_rxd2 */
			0xc0  ( PIN_INPUT  | MUX_MODE5 ) /* (A19) dss_data8.pr1_mii0_rxd3 */
			0xa4  ( PIN_OUTPUT | MUX_MODE2 ) /* (A21) dss_data1.pr1_mii0_txen */
			0xd8  ( PIN_INPUT  | MUX_MODE5 ) /* (C17) dss_data14.pr1_mii_mr0_clk */
			0xdc  ( PIN_INPUT  | MUX_MODE5 ) /* (D17) dss_data15.pr1_mii0_rxdv */
			0xd4  ( PIN_INPUT  | MUX_MODE5 ) /* (D19) dss_data13.pr1_mii0_rxer */
			0xd0  ( PIN_INPUT  | MUX_MODE5 ) /* (C19) dss_data12.pr1_mii0_rxlink */
			0x240 ( PIN_INPUT  | MUX_MODE5 ) /* (G20) gpio5_10.pr1_mii0_crs */
			0x238 ( PIN_INPUT  | MUX_MODE5 ) /* (D25) gpio5_8.pr1_mii0_col */
		>;
	};

- when board started reset signal recieved PHY - link LED responds to a LAN cable connection and seeing signals on RTX pins of PHY
- also whe checked signals on *CLK pins

Software & Tools part:
TI Linux kernel & U-Boot from latest SDK version 03.02.00.05
Buildroot 2016.08.1 as build system
gcc 5.3 2006.02 by linaro

So, no help from TI ... but we are making progress and have moved a little to solve our problem. Maybe it's useful info for someone.

What we did:

1. We compared design of our сustom board with AM437X-IDK-EVM from TI and MYB-C437X-PRU from MYIR Tech.

2. Revised recommendation to the PHY TLK105L

3. Applied some solutions from 1, 2.

After these steps, we have achieved a certain result. More precisely the result we had, but we did not know how to relate to that data.

We changed PHYADDR for testing purposes to 0x00 and commented string in DT compatible = "ethernet-phy-id2000.a210"; leaving only this

pruss1_eth0_phy: ethernet-phy@0 {
   reg = <0>;
};

dmesg says

[xxxx] davinci_mdio 54432400.mdio: davinci mdio revision 1.6
[xxxx] libphy: 54432400.mdio: probed
[xxxx] davinci_mdio 54432400.mdio: phy[0]: device 54432400.mdio:00, driver TI TLK10X 10/100 Mbps PHY

which mean Davinci MDIO bus worked and properly founded PHY on bus and appropriate driver. So, go to the next level
After "modprobe prueth" now we have next log message "prueth pruss1_eth: no ethernet-mii1 node" and that's all.
So we decided to search for the reason in the prueth driver. We added DEBUG macro and some additional debug info to the driver.
After adding debugging code and explore the source code driver, we have found the reason.
It consists in that the current version (0.2) prueth driver is designed to use only two ports (for AM437X family proccessors)!
If you use 1 port after the message "no ethernet-mii0 node" or "no ethernet-mii1 node" initialization terminated.

Commented out and changing some of the driver's code now we have a network device as eth0

Log after starting the module has become such a

[xxxxx] prueth pruss1_eth: port 1: using MAC addr from DT: a0: f6: fd: xx: xx: xx
[xxxxx] prueth pruss1_eth: TI PRU ethernet driver initialized

and then execute the command "ifconfig eth0 up" we have log messages such a

[xxxxx] remoteproc0: powering up 54434000.pru0
[xxxxx] remoteproc0: Booting fw image ti-pruss/am437x-pru0-prueth-fw.elf, size 4754
[xxxxx] ti-pruss 54400000.pruss: configured system_events = 0x0000060000500000 intr_channels = 0x00000095 host_intr = 0x00000115
[xxxxx] remoteproc0: remote processor 54434000.pru0 is now up
[xxxxx] net eth0: started
[xxxxx] eth0: Link is Up - 100Mbps/Full - flow control rx/tx

Unfortunately we now have a new problem - the device does not receive an address by DHCP protocol or after explicitly setting the address, don't send or receive any packets. But that's another issue for another day.

Sergii Khalo said:

Unfortunately we now have a new problem - the device does not receive an address by DHCP protocol or after explicitly setting the address, don't send or receive any packets. But that's another issue for another day.

This problem was solved. It was a hardware bug

Now last issue module prueth loaded before pru_rproc started
Temporary solution - rmmod prueth and then modprobe prueth
We using mdev as device manager
In my opinion best solution - change driver's source code.  NODEV to PROBE_DEFER in some parts of source code