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#include "packet_interface.h"
#include "noise.h"
#include "cobs.h"
#include "tracing.h"
#include <libopencm3/stm32/usart.h>
#include <libopencm3/stm32/dma.h>
#include <libopencm3/cm3/nvic.h>
#include <libopencmsis/core_cm3.h>
volatile struct {
struct dma_buf dma;
uint8_t data[256];
} usart2_buf = { .dma = { .len = sizeof(usart2_buf.data) } };
struct dma_usart_file usart2_out_s = {
.usart = USART2,
.baudrate = 115200,
.dma = DMA1,
.stream = 6,
.channel = 4,
.irqn = NVIC_DMA_IRQ(1, 6),
.buf = &usart2_buf.dma
};
struct dma_usart_file *usart2_out = &usart2_out_s;
void dma1_stream6_isr(void) {
TRACING_SET(TR_HOST_IF_DMA_IRQ);
static unsigned int fifo_errors = 0; /* debug */
if (dma_get_interrupt_flag(usart2_out->dma, usart2_out->stream, DMA_FEIF)) {
/* Ignore FIFO errors as they're 100% non-critical for UART applications */
dma_clear_interrupt_flags(usart2_out->dma, usart2_out->stream, DMA_FEIF);
fifo_errors++;
TRACING_CLEAR(TR_HOST_IF_DMA_IRQ);
return;
}
/* Transfer complete interrupt */
dma_clear_interrupt_flags(usart2_out->dma, usart2_out->stream, DMA_TCIF);
if (usart2_out->buf->wr_pos != usart2_out->buf->xfr_end) /* buffer not empty */
schedule_dma(usart2_out);
TRACING_CLEAR(TR_HOST_IF_DMA_IRQ);
}
void usart2_isr(void) {
TRACING_SET(TR_HOST_IF_USART_IRQ);
static struct cobs_decode_state host_cobs_state = {0};
if (USART2_SR & USART_SR_ORE) { /* Overrun handling */
LOG_PRINTF("USART2 data register overrun\n");
/* Clear interrupt flag */
(void)USART2_DR; /* FIXME make sure this read is not optimized out */
host_packet_length = -1;
TRACING_CLEAR(TR_HOST_IF_USART_IRQ);
return;
}
uint8_t data = USART2_DR; /* This automatically acknowledges the IRQ */
if (host_packet_length) {
LOG_PRINTF("USART2 COBS buffer overrun\n");
host_packet_length = -1;
TRACING_CLEAR(TR_HOST_IF_USART_IRQ);
return;
}
ssize_t rv = cobs_decode_incremental(&host_cobs_state, (char *)host_packet_buf, sizeof(host_packet_buf), data);
if (rv == 0) {
/* good, empty frame */
LOG_PRINTF("Got empty frame from host\n");
host_packet_length = -1;
} else if (rv == -1) {
/* Decoding frame, wait for next byte */
} else if (rv == -2) {
LOG_PRINTF("Host interface COBS framing error\n");
host_packet_length = -1;
} else if (rv == -3) {
/* invalid empty frame */
LOG_PRINTF("Got double null byte from host\n");
host_packet_length = -1;
} else if (rv == -4) {
/* frame too large */
LOG_PRINTF("Got too large frame from host\n");
host_packet_length = -1;
} else if (rv > 0) {
/* Good, non-empty frame */
host_packet_length = rv;
}
TRACING_CLEAR(TR_HOST_IF_USART_IRQ);
}
void send_packet(struct dma_usart_file *f, const uint8_t *data, size_t len) {
/* ignore return value as putf is blocking and always succeeds */
(void)cobs_encode_incremental(f, putf, (char *)data, len);
flush(f);
}
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