Host handshake mostly working

1 files changed, 16 insertions, 2 deletions

diff --git a/src/packet_interface.c b/src/packet_interface.c
index 071cf02..9c0ea5c 100644
--- a/src/packet_interface.c
+++ b/src/packet_interface.c
@@ -10,7 +10,7 @@
 
 volatile struct {
     struct dma_buf dma;
-    uint8_t data[128];
+    uint8_t data[256];
 } usart2_buf = { .dma = { .len = sizeof(usart2_buf.data) } };
 
 struct dma_usart_file usart2_out_s = {
@@ -25,7 +25,15 @@ struct dma_usart_file usart2_out_s = {
 struct dma_usart_file *usart2_out = &usart2_out_s;
 
 void dma1_stream6_isr(void) {
-	dma_clear_interrupt_flags(usart2_out->dma, usart2_out->stream, DMA_TCIF);
+    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);
+        LOG_PRINTF("USART2 DMA FIFO error\n");
+        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);
@@ -37,6 +45,7 @@ void usart2_isr(void) {
         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;
         return;
     }
 
@@ -44,14 +53,19 @@ void usart2_isr(void) {
 
     if (host_packet_length) {
         LOG_PRINTF("USART2 COBS buffer overrun\n");
+        host_packet_length = -1;
         return;
     }
 
     ssize_t rv = cobs_decode_incremental(&host_cobs_state, (char *)host_packet_buf, sizeof(host_packet_buf), data);
     if (rv == -2) {
         LOG_PRINTF("Host interface COBS packet too large\n");
+        host_packet_length = -1;
+    } else if (rv == -3) {
+        LOG_PRINTF("Got double null byte from host\n");
     } else if (rv < 0) {
         LOG_PRINTF("Host interface COBS framing error\n");
+        host_packet_length = -1;
     } else if (rv > 0) {
         host_packet_length = rv;
     } /* else just return and wait for next byte */