topic Re: UART Set RTSCTS DTE_mode Fail in i.MX Processors

UART Set RTSCTS DTE_mode Fail

frankweng — Wed, 13 Sep 2017 11:35:08 GMT

OS:Android6.0.1_2.0.0-ga

kernel : 4.1.15

dtsi 有關 ttymxc0/ttymxc3 設定

pinctrl_uart1: uart1grp {
fsl,pins = <
MX6QDL_PAD_CSI0_DAT10__UART1_TX_DATA 0x1b0b1
MX6QDL_PAD_CSI0_DAT11__UART1_RX_DATA 0x1b0b1
MX6QDL_PAD_EIM_D19__UART1_CTS_B 0x1b0b1
MX6QDL_PAD_EIM_D20__UART1_RTS_B 0x1b0b1
MX6QDL_PAD_EIM_D23__UART1_DCD_B 0x1b0b1
MX6QDL_PAD_EIM_D24__UART1_DTR_B 0x1b0b1
MX6QDL_PAD_EIM_D25__UART1_DSR_B 0x1b0b1
MX6QDL_PAD_EIM_EB3__UART1_RI_B 0x1b0b1
>;
};

pinctrl_uart4: uart4grp {
fsl,pins = <
MX6QDL_PAD_CSI0_DAT12__UART4_TX_DATA 0x1b0b1
MX6QDL_PAD_CSI0_DAT13__UART4_RX_DATA 0x1b0b1
MX6QDL_PAD_CSI0_DAT16__UART4_RTS_B 0x1b0b1
MX6QDL_PAD_CSI0_DAT17__UART4_CTS_B 0x1b0b1
>;
};

&uart1 {
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_uart1>;
fsl,dte-mode;
fsl,uart-has-rtscts;
status = "okay";
};

&uart4 {
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_uart4>;
fsl,uart-has-rtscts;
fsl,dte-mode;
status = "okay";
};

1、Uart 設定為 RTSCTS & DTE_mode 下

a:對ttymxc0

cmd: stty -F /dev/ttymxc0 raw ispeed 9600 ospeed 9600 cs8 -ignpar -cstopb -echo

設定ttymxc0() 時，整個系統會出現，但ttymxc3就不會

   mmc3: Timeout waiting for hardware interrupt.
   INFO: rcu_preempt self-detected stall on CPU
   0: (1 GPs behind) idle=8d3/2/0 softirq=7999/7999 fqs=2100
   (t=2100 jiffies g=3058 c=3057 q=46)
   Task dump for CPU 0:
   swapper/0 R running 0 0 0 0x00000002
   [<c01100e4>] (unwind_backtrace) from [<c010b554>] (show_stack+0x10/0x14)
   [<c010b554>] (show_stack) from [<c01859dc>] (rcu_dump_cpu_stacks+0x8c/0xc8)
   [<c01859dc>] (rcu_dump_cpu_stacks) from [<c0189894>] (rcu_check_callbacks+0x64c/0xa64)
   [<c0189894>] (rcu_check_callbacks) from [<c018eb34>] (update_process_times+0x38/0x64)
   [<c018eb34>] (update_process_times) from [<c019f1f4>] (tick_sched_handle+0x48/0x54)
   [<c019f1f4>] (tick_sched_handle) from [<c019f36c>] (tick_sched_timer+0x6c/0xc0)
   [<c019f36c>] (tick_sched_timer) from [<c018fb80>] (__run_hrtimer+0x88/0x2c0)
   [<c018fb80>] (__run_hrtimer) from [<c019004c>] (hrtimer_interrupt+0x124/0x294)
   [<c019004c>] (hrtimer_interrupt) from [<c010f8b8>] (twd_handler+0x30/0x38)
   [<c010f8b8>] (twd_handler) from [<c0180de4>] (handle_percpu_devid_irq+0x9c/0x1c8)
   [<c0180de4>] (handle_percpu_devid_irq) from [<c017ce24>] (generic_handle_irq+0x2c/0x3c)
   [<c017ce24>] (generic_handle_irq) from [<c017d0e0>] (__handle_domain_irq+0x7c/0xec)
   [<c017d0e0>] (__handle_domain_irq) from [<c0101450>] (gic_handle_irq+0x24/0x5c)
   unwind: Unknown symbol address c0101450
   unwind: Index not found c0101450

b:對ttymxc0 ()

i: cmd: stty -F /dev/ttymxc0 raw ispeed 9600 ospeed 9600 cs8 -ignpar -cstopb -echo <--無法作loopback

II:busybox stty -F /dev/ttymxc3 raw ispeed 9600 ospeed 9600 cs8 -ignpar -cstopb -echo -crtscts <--無法作loopback

2、Uart 設定為 RTSCTS 下

a:對ttymxc0

stty -F /dev/ttymxc0 raw ispeed 9600 ospeed 9600 cs8 -ignpar -cstopb -echo

不會出現任何kernel panic，但是無法作loopback

b:對ttymxc3

stty -F /dev/ttymxc3 raw ispeed 9600 ospeed 9600 cs8 -ignpar -cstopb -echo --> 可以loopback

stty -F /dev/ttymxc3 raw ispeed 9600 ospeed 9600 cs8 -ignpar -cstopb -echo crtscts --> 可以loopback ，RTS/CTS 無作用

請問是否有patch檔可以解決，謝謝

Re: UART Set RTSCTS DTE_mode Fail

BiyongSUN — Thu, 14 Sep 2017 08:57:30 GMT

Please check the binding guide

Documentation/devicetree/bindings/serial/fsl-imx-uart.txt

1 * Freescale i.MX Universal Asynchronous Receiver/Transmitter (UART)
2
3 Required properties:
4 - compatible : Should be "fsl,<soc>-uart"
5 - reg : Address and length of the register set for the device
6 - interrupts : Should contain uart interrupt
7
8 Optional properties:
9 - fsl,uart-has-rtscts : Indicate the uart has rts and cts
10 - fsl,irda-mode : Indicate the uart supports irda mode
11 - fsl,dte-mode : Indicate the uart works in DTE mode. The uart works
12                   is DCE mode by default.
13
14 Note: Each uart controller should have an alias correctly numbered
15 in "aliases" node.
16
17 Example:
18
19 aliases {
20         serial0 = &uart1;
21 };
22
23 uart1: serial@73fbc000 {
24         compatible = "fsl,imx51-uart", "fsl,imx21-uart";
25         reg = <0x73fbc000 0x4000>;
26         interrupts = <31>;
27         fsl,uart-has-rtscts;
28         fsl,dte-mode;
29 };

example imx6ull-14x14-evk.dts

690 &uart2 {
691         pinctrl-names = "default";
692         pinctrl-0 = <&pinctrl_uart2>;
693         fsl,uart-has-rtscts;
694         /* for DTE mode, add below change */
695         /* fsl,dte-mode; */
696         /* pinctrl-0 = <&pinctrl_uart2dte>; */
697         status = "okay";
698 };

Re: UART Set RTSCTS DTE_mode Fail

igorpadykov — Thu, 14 Sep 2017 09:16:10 GMT

Hi Frank

kernel panic may be due to ddr errors, please run board ddr test and update

image with new calibration coefficients

i.MX6/7 DDR Stress Test Tool V2.70

Also one can try to rebuild image anew from scratch.

Best regards
igor
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