Tina Linux UART flow control

[lecndav]

Hi, I suspect that UART flow control (RTS, CTS) does not work on the sipeed lichee rv dock (D1 chip) board with Tina linux. I came to the assumption after testing bluetooth (RTL8723DS). In general BT works, but if the CPU is very busy, I get "Bluetooth: Out-of-order packet arrived (6 != 7)" from the kernel. The device tree is configured as followed:

uart1_pins_a: uart1_pins@0 {
		pins = "PG6", "PG7", "PG8", "PG9";
		function = "uart1";
		drive-strength = <10>;
		bias-pull-up;
};

uart1_pins_b: uart1_pins {
		pins = "PG6", "PG7", "PG8", "PG9";
		function = "gpio_in";
};

&uart1 {
	uart-has-rtscts;
	pinctrl-names = "default";
	pinctrl-0 = <&uart1_pins_a>;
	pinctrl-1 = <&uart1_pins_b>;
	status = "okay";
};

I assume something is wrong in the device tree and CTS RTS is not activated. Is there something else to activate flow controls?

[whycan]

@lecndav

用逻辑分析仪或者示波器接上 PG6 ~ PG9

Connect PG6 ~ PG9 with logic analyzer or oscilloscope

[lecndav]

@whycan Yes, I connected RX TX RTS CTS to an oscilloscope yesterday. I observed that the Realtek chip is using his RTS line, but I saw nothing on the other line.

[whycan]

@lecndav 在 Tina Linux UART flow control 中说：

Yes, I connected RX TX RTS CTS to an oscilloscope yesterday. I observed that the Realtek chip is using his RTS line, but I saw nothing on the other line

yes, only 3-wire for rtl8723ds

[lecndav]

@whycan Ah I see. The problem only occurs on many I/O interrupts. So for example when executing "find /" on the console or via SSH. I could maybe workaround this problem on software side. Do you recommend another WIFI + BT chip which has 4 wire UART and is compatible with D1 without a lot of driver adaptions?