File content as of revision 2:fe2fcaa72434:

#include "SimpleDMA.h"

#define DMA_CHANNELS        4

SimpleDMA *SimpleDMA::irq_owner[4] = {NULL};

SimpleDMA::SimpleDMA(int channel) {
    this->channel(channel);
       
    //Enable DMA
    SIM->SCGC6 |= 1<<1;     //Enable clock to DMA mux
    SIM->SCGC7 |= 1<<8;     //Enable clock to DMA
    
    trigger(Trigger_ALWAYS);
    
    DCR = (1<<29) + (1<<30);   //Set to always use DMAMUX (If no trigger is needed we route via alwayson)

    uint32_t handler = NULL;
    switch (_channel) {
        case 0:
            handler = (uint32_t)&irq_handler0;
            break;
        case 1:
            handler = (uint32_t)&irq_handler1;
            break;
        case 2:
            handler = (uint32_t)&irq_handler2;
            break;
        case 3:
            handler = (uint32_t)&irq_handler3;
            break;
        default:
            break;
    }

    NVIC_SetVector((IRQn) (DMA0_IRQn + _channel), handler);
    NVIC_EnableIRQ((IRQn) (DMA0_IRQn + _channel));

    irq_owner[_channel] = this;
}

int SimpleDMA::setAddress(uint32_t address, int wordsize, bool source, bool autoinc) {
    //Check if it is an allowed address
    switch ((uint32_t) address >> 20) {
        case 0x000:
        case 0x1FF:
        case 0x200:
        case 0x400:
        break;
        default:
            return -1;
        }
    
    char _size;
    switch (wordsize) {
        case 8:
            _size = 1;
            break;
        case 16:
            _size = 2;
            break;
        case 32:
            _size = 0;
            break;
        default:
            _size = 1;
        }
    
    //Check if source or destination
    if (source) {
        SAR = address;
        DCR &= ~(7<<20);
        DCR |= autoinc << 22;
        DCR |= _size << 20;
    } else {
        DAR = address;
        DCR &= ~(7<<17);
        DCR |= autoinc << 19;
        DCR |= _size << 17;
    }
    return 0;
};

int SimpleDMA::trigger(SimpleDMA_Trigger trig){ 
    
    CHCFG = trig;
    return 0;
}

int SimpleDMA::start(int length) {
    while(isBusy());
    DMA0->DMA[_channel].DSR_BCR |= DMA_DSR_BCR_DONE_MASK ;
    
    if (length > 0xFFFFF)
        return -1;
    
    if (irq_en)
        DCR |= (1UL<<31);
    else
        DCR &= ~(1UL<<31);
    
    //Set registers:
    DMA0->DMA[_channel].SAR = SAR;
    DMA0->DMA[_channel].DAR = DAR;
    DMA0->DMA[_channel].DCR = DCR;
    
    //Set trigger
    DMAMUX0->CHCFG[_channel] = CHCFG;
    
    //Set length
    DMA0->DMA[_channel].DSR_BCR = length;
        
    //Start
    DMAMUX0->CHCFG[_channel] |= 1<<7;
    
    return 0;
}

void SimpleDMA::channel(int chan) {
    if (chan >= 0 && chan < DMA_CHANNELS)
        _channel = chan;
    else
        _channel = 3;
}

bool SimpleDMA::isBusy( void ) {
    //Busy bit doesn't work as I expect it to do, so just check if counter is at zero
    //return (DMA0->DMA[_channel].DSR_BCR & (1<<25) == 1<<25);
    return (DMA0->DMA[_channel].DSR_BCR &0xFFFFFF);
}

void SimpleDMA::irq_handler(void) {
    DMAMUX0->CHCFG[_channel] = 0;
    DMA0->DMA[_channel].DSR_BCR |= DMA_DSR_BCR_DONE_MASK ; 
    _callback.call();
}