example_i2s: interrupt service routine never runs

[grinningmosfet]

Summary

In the example_i2s example, the interrupt service routine should set a flag to print irq 1 on the serial output via the PRINTF macro when the internal I2S FIFO's watermark is reached:

void handler_irq_i2s(uint32_t id) {
    i2s_interrupt_flag = 1;
}

...

int main(int argc, char *argv[]) {

...

  if (i2s_interrupt_flag) {
      PRINTF("irq 1\r\n\r");
      i2s_interrupt_flag = 0;
  }

...

}

But it does not. The interrupt does not seem to be handled.

Steps to reproduce

Run the example_i2s example according to the docs.

• Clone the X-HEEP repository
• Open a shell in the x-heep directory and issue the following commands:
• conda activate core-v-mini-mcu
• make mcu-gen
• Edit x-heep/sw/applications/example_i2s/main.c by replacing the line #define PRINTF_IN_SIM 0 by #define PRINTF_IN_SIM 1
• make app PROJECT=example_i2s
• make verilator-sim
• cd ./build/openhwgroup.org_systems_core-v-mini-mcu_0/sim-verilator
• ./Vtestharness +firmware=../../../sw/build/main.hex
• cat uart0.log

Expected behaviour

Finding some irq 1s into the uart0.log logs file.

Actual behaviour

uart0.log logs the following:

I2S DEMO
 Valid:  0
 Load:   0
 B0
 0x8765431 0xfedcba9
 0x8765431 0xfedcba9
 B1
 0x8765431 0xfedcba9
 0x8765431 0xfedcba9
 B2
 0x8765431 0xfedcba9
 0x8765431 0xfedcba9
 B3
 0x8765431 0xfedcba9
 0x8765431 0xfedcba9
 Success.

The program exit value is 0. There is not a single standalone irq 1 printed.

[grinningmosfet]

The function's declaration actually called is that implemented in x-heep/sw/device/lib/drivers/i2s/i2s.c. Removing it fixes the issue.