panda/board/stm32f4/llspi.h

92 lines
2.7 KiB
C

#if defined(ENABLE_SPI) || defined(BOOTSTUB)
void llspi_miso_dma(uint8_t *addr, int len) {
// disable DMA
DMA2_Stream3->CR &= ~DMA_SxCR_EN;
register_clear_bits(&(SPI1->CR2), SPI_CR2_TXDMAEN);
// setup source and length
register_set(&(DMA2_Stream3->M0AR), (uint32_t)addr, 0xFFFFFFFFU);
DMA2_Stream3->NDTR = len;
// enable DMA
register_set_bits(&(SPI1->CR2), SPI_CR2_TXDMAEN);
DMA2_Stream3->CR |= DMA_SxCR_EN;
}
void llspi_mosi_dma(uint8_t *addr, int len) {
// disable DMA
register_clear_bits(&(SPI1->CR2), SPI_CR2_RXDMAEN);
DMA2_Stream2->CR &= ~DMA_SxCR_EN;
// drain the bus
volatile uint8_t dat = SPI1->DR;
(void)dat;
// setup destination and length
register_set(&(DMA2_Stream2->M0AR), (uint32_t)addr, 0xFFFFFFFFU);
DMA2_Stream2->NDTR = len;
// enable DMA
DMA2_Stream2->CR |= DMA_SxCR_EN;
register_set_bits(&(SPI1->CR2), SPI_CR2_RXDMAEN);
}
// SPI MOSI DMA FINISHED
static void DMA2_Stream2_IRQ_Handler(void) {
// Clear interrupt flag
ENTER_CRITICAL();
DMA2->LIFCR = DMA_LIFCR_CTCIF2;
spi_rx_done();
EXIT_CRITICAL();
}
// SPI MISO DMA FINISHED
static void DMA2_Stream3_IRQ_Handler(void) {
// Clear interrupt flag
DMA2->LIFCR = DMA_LIFCR_CTCIF3;
// Wait until the transaction is actually finished and clear the DR
// Timeout to prevent hang when the master clock stops.
bool timed_out = false;
uint32_t start_time = microsecond_timer_get();
while (!(SPI1->SR & SPI_SR_TXE)) {
if (get_ts_elapsed(microsecond_timer_get(), start_time) > SPI_TIMEOUT_US) {
timed_out = true;
break;
}
}
volatile uint8_t dat = SPI1->DR;
(void)dat;
SPI1->DR = 0U;
if (timed_out) {
print("SPI: TX timeout\n");
}
spi_tx_done(timed_out);
}
// ***************************** SPI init *****************************
void llspi_init(void) {
REGISTER_INTERRUPT(DMA2_Stream2_IRQn, DMA2_Stream2_IRQ_Handler, SPI_IRQ_RATE, FAULT_INTERRUPT_RATE_SPI_DMA)
REGISTER_INTERRUPT(DMA2_Stream3_IRQn, DMA2_Stream3_IRQ_Handler, SPI_IRQ_RATE, FAULT_INTERRUPT_RATE_SPI_DMA)
// Setup MOSI DMA
register_set(&(DMA2_Stream2->CR), (DMA_SxCR_CHSEL_1 | DMA_SxCR_CHSEL_0 | DMA_SxCR_MINC | DMA_SxCR_TCIE), 0x1E077EFEU);
register_set(&(DMA2_Stream2->PAR), (uint32_t)&(SPI1->DR), 0xFFFFFFFFU);
// Setup MISO DMA
register_set(&(DMA2_Stream3->CR), (DMA_SxCR_CHSEL_1 | DMA_SxCR_CHSEL_0 | DMA_SxCR_MINC | DMA_SxCR_DIR_0 | DMA_SxCR_TCIE), 0x1E077EFEU);
register_set(&(DMA2_Stream3->PAR), (uint32_t)&(SPI1->DR), 0xFFFFFFFFU);
// Enable SPI and the error interrupts
// TODO: verify clock phase and polarity
register_set(&(SPI1->CR1), SPI_CR1_SPE, 0xFFFFU);
register_set(&(SPI1->CR2), 0U, 0xF7U);
NVIC_EnableIRQ(DMA2_Stream2_IRQn);
NVIC_EnableIRQ(DMA2_Stream3_IRQn);
}
#endif