STM32MP157 UART8 Interrupt issue

[KKett.2]

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

[JeanPhilippeR]

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]

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

[JeanPhilippeR]

Hi @Community member​ 

Thank you for outputs.

Which version of OpenSTLinux are you using?

BR

Jean-Philippe

[KKett.2]

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