Sending buffer on UART with DMA - arm

Question

First I initialize DMA
void DMA_Init(void)
{
//enable clock for DMAMUX and DMA
SIM_SCGC6 |= SIM_SCGC6_DMAMUX0_MASK;
SIM_SCGC7 |= SIM_SCGC7_DMA_MASK;
//enable channel 0 and set the source - 3 = UART0 Transmit ($3.3.9.1 Table 3-26)
DMAMUX0_CHCFG0 |= DMAMUX_CHCFG_ENBL_MASK | DMAMUX_CHCFG_SOURCE(3);
//enable request signal for channel 0
DMA_ERQ = DMA_ERQ_ERQ0_MASK;
//set memory address for source and destination
DMA_TCD0_SADDR = (uint32_t)&log_buffer_data_1; //global scope buffer
DMA_TCD0_DADDR = (uint32_t)&UART0_D;
//set an offset
//increment the address by one, after each cycle
DMA_TCD0_SOFF = 1;
DMA_TCD0_DOFF = 0;
//set data transfer size - 0 = byte
DMA_TCD0_ATTR = DMA_ATTR_SSIZE(0) | DMA_ATTR_DSIZE(0);
//number of bytes to be transfered in each service request
//minor byte transfer count
DMA_TCD0_NBYTES_MLNO = glob_data_chank;
//current major iteration count (a single iteration)
//current major iteration count
DMA_TCD0_CITER_ELINKNO = DMA_CITER_ELINKNO_CITER(1);
//starting major iteration count
DMA_TCD0_BITER_ELINKNO = DMA_BITER_ELINKNO_BITER(1);
DMA_TCD0_SLAST = 0; //???
DMA_TCD0_DLASTSGA = 0; //???
//setup control and status register
//should be inactive before write
DMA_TCD0_CSR = 0;
//interrupt when tx/rx buffer is full. stop DMA on single transfer.
DMA_TCD0_CSR = DMA_CSR_INTMAJOR_MASK | DMA_CSR_DREQ_MASK;
}
At this point I have some questions
Do I need the interrupt? I can poll the done flag
while (DMA_TCD0_CSR & DMA_CSR_DONE_MASK)
How do I start a new transaction? Is START flag enough?
DMA_TCD0_CSR |= DMA_CSR_START_MASK;
Right now my send fuction looks like this
void DMA_Start(uint8_t *data, uint32_t pakage_size)
{
while ((DMA_TCD0_CSR & DMA_CSR_DONE_MASK) == 0);
//size to be transferred - reload each request
DMA_TCD0_NBYTES_MLNO = pakage_size;
//set memory address for source and destination - reload each request?
DMA_TCD0_SADDR = (uint32_t)&data;
//DMA_TCD0_DADDR = (uint32_t)&UART0_D;
//current major iteration count - reload each request?
DMA_TCD0_CITER_ELINKNO = DMA_CITER_ELINKNO_CITER(1);
//starting major iteration count
DMA_TCD0_BITER_ELINKNO = DMA_BITER_ELINKNO_BITER(1);
//enable auto disable request feature
DMA_TCD0_CSR |= DMA_CSR_DREQ_MASK;
//enable major interrupt
DMA_TCD0_CSR |= DMA_CSR_INTMAJOR_MASK;
//re-enable channel request
DMA_SERQ = DMA_SERQ_SERQ(0);
DMA_TCD0_CSR |= DMA_CSR_START_MASK;
}
And I don't know if it's good for send.