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STM32MP157 UART8 Interrupt issue

KKett.2
Associate II

I've assigned the UART8 device in the devicetree of the linux kernel (OpenSTLinux):

&pinctrl {
// ...
	uart8_pins: uart8-0 {
			pins1 {
					pinmux = <STM32_PINMUX('E', 0, AF8)>; /* UART8_RX */
					bias-disable;
			};
			pins2 {
					pinmux = <STM32_PINMUX('E', 1, AF8)>; /* UART8_TX */
					bias-disable;
					drive-push-pull;
					slew-rate = <0>;
			};
	};
 
	uart8_sleep_pins: uart8-sleep-0 {
			pins {
					pinmux = <STM32_PINMUX('E', 0, ANALOG)>, /* UART8_RX */
							 <STM32_PINMUX('E', 1, ANALOG)>; /* UART8_TX */
			};
	};
// ...
}
// ...
&uart8 {
        pinctrl-names = "default", "sleep";
        pinctrl-0 = <&uart8_pins>;
        pinctrl-1 = <&uart8_sleep_pins>;
        /delete-property/dmas;
        /delete-property/dma-names;
        status = "okay";
};

The uart8 (0x40019000) is detected upon boot and the device /dev/STM1 is created:

[   1.196012] stm32-usart 40010000.serial: interrupt mode for rx (no dma)
[   1.196036] stm32-usart 40010000.serial: interrupt mode for tx (no dma)
[   1.196076] 40010000.serial: ttySTM0 at MMIO 0x40010000 (irq = 53, base_baud = 4000000) is a stm32-usart
[   2.321957] stm32-usart 40019000.serial: interrupt mode for rx (no dma)
[   2.327129] stm32-usart 40019000.serial: interrupt mode for tx (no dma)
[   2.333894] 40019000.serial: ttySTM1 at MMIO 0x40019000 (irq = 54, base_baud = 4000000) is a stm32-usart

Sending on TX is working fine, but we can't receive anything. Looking into the interrupt table in linux, i see that the interrupt for UART8 should be on irq 54, bit i can't find anything there:

root@hp00164:~# cat /proc/tty/driver/stm32-usart
serinfo:1.0 driver revision:
0: uart:stm32-usart mmio:0x40010000 irq:53 tx:76167 rx:1466 RTS|CTS|DTR|DSR|CD
1: uart:stm32-usart mmio:0x40019000 irq:54 tx:25 rx:0 CTS|DSR|CD
 
root@hp00164:~# cat /proc/interrupts | grep ".serial"
 53:       8959          0  stm32-exti-h-direct  30 Level     40010000.serial

What could be the reason for the missing irq? Is this even the issue for not receiving data?

I appreciate any help, thank you.

Best regards,

Kevin

1 ACCEPTED SOLUTION

Accepted Solutions

Hi @JeanPhilippeR​ ,

it's working now, it was a hardware issue. 😅

Thank you for your help!

Best regards,

Kevin

View solution in original post

8 REPLIES 8
JeanPhilippeR
ST Employee

Hi @Community member​ 

Do you have a look to the wiki page https://wiki.st.com/stm32mpu/wiki/Trace_and_debug_scenario_-_UART_issue

which provide some guidelines for such issue?

BR

Jean-Philippe

KKett.2
Associate II

Hello Jean-Philippe,

thank you for the url. After looking into it, i see that for uart8_k (count=0) the clock is not enabled:

root@hp00164:~# grep -E "clock|uart" /sys/kernel/debug/clk/clk_summary | sed 's,\s\+, ,g' | column -t
clock    count  count  count  rate       accuracy  phase  cycle
uart8_k  0      0      0      64000000   0         0      50000
uart7_k  0      0      0      64000000   0         0      50000
uart6_k  0      0      0      64000000   0         0      50000
uart5_k  0      0      0      64000000   0         0      50000
uart4_k  1      1      0      64000000   0         0      50000
uart8    0      0      0      104438965  0         0      50000
uart7    0      0      0      104438965  0         0      50000
uart5    0      0      0      104438965  0         0      50000
uart4    0      0      0      104438965  0         0      50000

The rest seems to look good:

root@hp00164:~# cat /sys/kernel/debug/pinctrl/soc\:pin-controller\@50002000/pinmux-pins | grep 40019000
pin 64 (PE0): device 40019000.serial function af8 group PE0
pin 65 (PE1): device 40019000.serial function af8 group PE1

Here the complete interrupt table:

root@hp00164:~# cat /proc/interrupts
           CPU0       CPU1
 18:      19857      42464     GIC-0  27 Level     arch_timer
 20:          0          0     GIC-0 232 Level     arm-pmu
 21:          0          0     GIC-0 233 Level     arm-pmu
 22:          0          0     GIC-0  43 Level     dma1chan0
 23:          0          0     GIC-0  44 Level     dma1chan1
 24:          0          0     GIC-0  45 Level     dma1chan2
 25:          0          0     GIC-0  46 Level     dma1chan3
 26:          0          0     GIC-0  47 Level     dma1chan4
 27:          0          0     GIC-0  48 Level     dma1chan5
 28:          0          0     GIC-0  49 Level     dma1chan6
 29:          0          0     GIC-0  79 Level     dma1chan7
 30:          0          0     GIC-0  88 Level     dma2chan0
 31:          0          0     GIC-0  89 Level     dma2chan1
 32:          0          0     GIC-0  90 Level     dma2chan2
 33:          0          0     GIC-0  91 Level     dma2chan3
 34:          0          0     GIC-0  92 Level     dma2chan4
 35:          0          0     GIC-0 100 Level     dma2chan5
 36:          0          0     GIC-0 101 Level     dma2chan6
 37:          0          0     GIC-0 102 Level     dma2chan7
 38:         32          0     GIC-0 169 Level     mmci-pl18x (cmd)
 39:          0          0     GIC-0  37 Level     rcc irq
 41:          0          0     GIC-0 179 Level     stm_thermal
 42:          0          0     GIC-0 112 Level     54002000.hash
 43:          2          0     GIC-0 154 Level     58000000.dma
 44:          0          0     GIC-0 124 Level     58003000.spi
 45:       7548          0     GIC-0  81 Level     mmci-pl18x (cmd)
 46:        413          0     GIC-0 156 Level     mmci-pl18x (cmd)
 47:       3837          0     GIC-0  93 Level     eth0
 48:          1          0     GIC-0 106 Level     ohci_hcd:usb2
 49:        902          0     GIC-0 120 Level     5a001000.display-controller
 50:          0          0     GIC-0 121 Level     5a001000.display-controller
 51:          0          0     GIC-0 141 Level     59000000.gpu
 52:          0          0     GIC-0 111 Level     54001000.cryp
 53:      11625          0  stm32-exti-h-direct  30 Level     40010000.serial
 55:          0          0  stm32-exti-h-direct  70 Level     eth0
 56:          0          0  stm32-exti-h-direct  43 Level     ehci_hcd:usb1
 57:          0          0  stm32-exti-h-direct  22 Level     40013000.i2c
 58:          0          0     GIC-0  66 Level     40013000.i2c
 60:        248          0  stm32-exti-h-direct  24 Level     5c002000.i2c
 61:          0          0     GIC-0 128 Level     5c002000.i2c
 62:          0          0  stm32-exti-h  55 Edge      pmic_irq
 63:          0          0  pmic_irq  16 Edge      5c002000.i2c:stpmic@33:regulators
 64:          0          0  pmic_irq  17 Edge      5c002000.i2c:stpmic@33:regulators
 65:          0          0  pmic_irq  19 Edge      5c002000.i2c:stpmic@33:regulators
 66:          0          0  pmic_irq  20 Edge      5c002000.i2c:stpmic@33:regulators
 67:          0          0  pmic_irq  21 Edge      5c002000.i2c:stpmic@33:regulators
 68:          0          0  pmic_irq  14 Edge      5c002000.i2c:stpmic@33:regulators
 69:          0          0  pmic_irq  12 Edge      5c002000.i2c:stpmic@33:regulators
 70:          0          0  pmic_irq  13 Edge      5c002000.i2c:stpmic@33:regulators
 71:          0          0  stm32-exti-h-direct  61 Edge      4c001000.mailbox
 72:          0          0     GIC-0 133 Level     4c001000.mailbox
 73:          0          0  stm32-exti-h-direct  44 Level     49000000.usb-otg, 49000000.usb-otg
IPI0:          0          0  CPU wakeup interrupts
IPI1:          0          0  Timer broadcast interrupts
IPI2:       1625       7452  Rescheduling interrupts
IPI3:         67        132  Function call interrupts
IPI4:          0          0  CPU stop interrupts
IPI5:       8684      28936  IRQ work interrupts
IPI6:          0          0  completion interrupts
Err:          0

Hi @Community member​ 

Thank you for outputs.

Which version of OpenSTLinux are you using?

BR

Jean-Philippe

Hi @JeanPhilippeR​,

we are using dunfell 5.4, the latest distribution.

Linux hp00164 5.4.31 #1 SMP PREEMPT Wed Apr 8 07:08:47 UTC 2020 armv7l armv7l armv7l GNU/Linux

Thanks,

Kevin

Note also that to get the interrupt present in the /proc/interrupts you have to listen for the port in Rx, i.e. cat /dev/ttySTM1.

How do you perform the Rx test on your side?

thank you

BR

Jean-Philippe

Hi @JeanPhilippeR​ 

the RX and TX pins are connected together.

In the one terminal window i'm using cat for listing on the port:

root@hp00164:~# stty -a -F /dev/ttySTM1
speed 9600 baud; rows 0; columns 0; line = 0;
intr = ^C; quit = ^\; erase = ^?; kill = ^U; eof = ^D; eol = <undef>; eol2 = <undef>; swtch = <undef>; start = ^Q; stop = ^S;
susp = ^Z; rprnt = ^R; werase = ^W; lnext = ^V; discard = ^O; min = 1; time = 0;
-parenb -parodd -cmspar cs8 hupcl -cstopb cread clocal -crtscts
-ignbrk -brkint -ignpar -parmrk -inpck -istrip -inlcr -igncr icrnl ixon -ixoff -iuclc -ixany -imaxbel -iutf8
opost -olcuc -ocrnl onlcr -onocr -onlret -ofill -ofdel nl0 cr0 tab0 bs0 vt0 ff0
isig icanon iexten echo echoe echok -echonl -noflsh -xcase -tostop -echoprt echoctl echoke -flusho -extproc
root@hp00164:~# cat /dev/ttySTM1

On the other terminal, i'm writing with echo:

root@hp00164:~# echo "Test" > /dev/ttySTM1

But nothing is displayed on the other terminal.

When i'm listing on the port with cat, the clock is now activated, so that seems fine.

Thank you.

Best regards,

Kevin

Hi @JeanPhilippeR​ ,

it's working now, it was a hardware issue. 😅

Thank you for your help!

Best regards,

Kevin

Hi @Community member​ 

Good news, thank you for your feedback.

BR

Jean-Philippe