mbed-OS porting to TivaC TM4123, Trouple with dynamic interrupt handling

Question

Recently I'm trying to port mbed-OS to Tiva-C launchpad TM4C123, I am facing problem with file supplied by mbed which is cmsis_nvic.c and cmsis_nvic.h

This module is supposed to dynamically allocate the interrupt handler of OS timer to addressable function.(Or as far as I understand).

What happen is, The software jumps to "Hard Fault Handler" after executing the following line

vectors[i] = old_vectors[i];

Here's files which I use

#include "cmsis_nvic.h"

#define NVIC_RAM_VECTOR_ADDRESS (0x02000000)  // Vectors positioned at start of RAM
#define NVIC_FLASH_VECTOR_ADDRESS (0x0)       // Initial vector position in flash

void NVIC_SetVector(IRQn_Type IRQn, uint32_t vector) {
    uint32_t *vectors = (uint32_t*)SCB->VTOR;
    uint32_t i;

    // Copy and switch to dynamic vectors if the first time called
    if (SCB->VTOR == NVIC_FLASH_VECTOR_ADDRESS) {
        uint32_t *old_vectors = vectors;
        vectors = (uint32_t*)NVIC_RAM_VECTOR_ADDRESS;
        for (i=0; i<NVIC_NUM_VECTORS; i++) {
            vectors[i] = old_vectors[i];
        }
        SCB->VTOR = (uint32_t)NVIC_RAM_VECTOR_ADDRESS;
    }
    vectors[IRQn + 16] = vector;
}

uint32_t NVIC_GetVector(IRQn_Type IRQn) {
    uint32_t *vectors = (uint32_t*)SCB->VTOR;
    return vectors[IRQn + 16];
}

And here is cmsis_nvic.h

#ifndef MBED_CMSIS_NVIC_H
#define MBED_CMSIS_NVIC_H

#define NVIC_NUM_VECTORS      (154)   // CORE + MCU Peripherals
#define NVIC_USER_IRQ_OFFSET  16

#include "cmsis.h"

#ifdef __cplusplus
extern "C" {
#endif

void NVIC_SetVector(IRQn_Type IRQn, uint32_t vector);
uint32_t NVIC_GetVector(IRQn_Type IRQn);

#ifdef __cplusplus
}
#endif

#endif

and I am calling

NVIC_SetVector(IRQn_Type IRQn, uint32_t vector)

from file us_ticker.c like this

NVIC_SetVector(TIMER0A_IRQn, (uint32_t)us_ticker_irq_handler);

(my compiler is ARM GCC, I am using CDT for building, And GDB openOCD for debugging, and integrated all those tools on Eclipse)

Can anyone please let me know what is going wrong here? or at least where should I debug or read to help me solve this problem???

UPDATE

I figured out part of the problem, The vector is not pointing to the first address of the target SRAM which should be

#define NVIC_RAM_VECTOR_ADDRESS (0x20000000)

instead of

#define NVIC_RAM_VECTOR_ADDRESS (0x02000000)

So now when calling NVIC_SetVector , the function is executed. But then when enabling the interrupt, Software still jumps to Hard Fault, I guess(just guessing or might be part of solution) that the defines in the header file are not configured correctly, Can someone explain to me what do they mean? and how to calculate the number of vector addresses? and what is the USER OFFSET?

Answer 1

I have solved this issue, here's what I have found

1- NVIC_RAM_VECTOR_ADDRESS wasn't the first address of my target RAM which should be `0x20000000'

2- Linker file should be update so that the stack pointer shouldn't write over the new copied vector table. So shift the RAM address by number of bytes that vector table should occupy.

3-(THE MAIN CAUSE) inside function NVIC_SetVector , i was declared as uint32_t and then compared to less than 255 pre-processor value. So compile get confused by comparing uint32_t with uint8_t , by adding UL to the pre-processor value, it solved the whole issue.