XIRQ interrupt handler (NEORV32 RISC-V Processor - Zephyr)

[SteveZ-Cal]

Zephyr

V3.4.0

Board (NEORV32 RISC-V Processor)

V1.8.6 (currently supported version)

Initial FPGA Setup

Upload NEORV32 RISC-V Processor on Cyclone V DE0-CV

Code

#define MY_DEV_IRQ 17
#define MY_DEV_IRQ_PRIO 1
#define MY_ISR_ARG 0
#define MY_IRQ_FLAGS 0

void my_isr(void *arg){

	printf("INSIDE my_isr\n");
 	//__asm__ volatile ("jalr ra, %0" : : "r" (0x00020000)); 

}

void my_isr_installer(void){

	printf("Inside my_isr_installer\n");
	IRQ_CONNECT(MY_DEV_IRQ, MY_DEV_PRIO, my_isr, MY_ISR_ARG, MY_IRQ_FLAGS);
	printf("ISR-Enabled\n");
   	irq_enable(MY_DEV_IRQ);
	printf("IRQ-Enabled\n");

}

void main(void){

	printf("START IN MAIN\n");
	my_isr_installer();

        ....... (rest of the code)

}

FIRQ table for neorv32.dtsi

		intc: interrupt-controller {
			compatible = "riscv,cpu-intc";
			interrupt-controller;
			#address-cells = <1>;
			#interrupt-cells = <1>;

			firq: firq {
				#address-cells = <1>;
				interrupt-map-mask = <0x0 0xffffffff>;
				interrupt-map = <
					0  0 &intc 0 16
					0  1 &intc 0 17
					0  2 &intc 0 18
					0  3 &intc 0 19
					0  4 &intc 0 20
					0  5 &intc 0 21
					0  6 &intc 0 22
					0  7 &intc 0 23
					0  8 &intc 0 24
					0  9 &intc 0 25
					0 10 &intc 0 26
					0 11 &intc 0 27
					0 12 &intc 0 28
					0 13 &intc 0 29
					0 14 &intc 0 30
					0 15 &intc 0 31
				>;
				#interrupt-cells = <1>;
			};
		};

Interrupt Setup:

I'm trying to control the Custom Functions Subsystem (CFS) of the NEORV32, which has { 0 1 &intc 0 17 } from the interrupt-map above. (Press switch 'SW9' cfs_in_i(0) on FPGA to indicate an interrupt occurs)

Below is my self-implemented corresponding NEORV32 CFS irq_process in vhdl (try to catch only one pulse upon press switch) :

irq_process: process(rstn_i, clk_i)
begin
        if (rstn_i = '0') then
            irq_cfs <= '0';
            irq_cfs_dly <= '0';
        elsif rising_edge(clk_i) then
                irq_cfs_dly <= irq_cfs;
               if cfs_in_i(0) = '1' then
                   irq_cfs <= '1';
              else
                   irq_cfs <= '0';
              end if;
        end if;
end process irq_process;
irq_o <= irq_cfs and (not irq_cfs_dly); -- getting CFS Interrupt One pulse 

Problems:

(1) I tested that I was able to achieve an interrupt when I press SW9, but it just stays in the my_isr, (Ex: keeps printing "INSIDE my_isr" as indicated by my_isr), and not return after this.

If (1) could be solved, I want PC_Jump features in my_isr

(2) Whenever an interrupt occurs, I want my PC jump to a specific portion of the memory like 0x20000 as indicated by my uncommented part in my_isr.