px4io: fixed the io_reg_{set,get} errors

this fixes the PX4IO state machine to avoid the io errors we were
seeing. There are still some open questions with this code, but it now
seems to give zero errors, which is an improvement!

src/modules/px4iofirmware/i2c.c

@@ -149,12 +149,6 @@ interface_init(void)
 #endif
 }
 
-void
-interface_tick()
-{
-}
-
-
 /*
   reset the I2C bus
   used to recover from lockups

src/modules/px4iofirmware/px4io.c

@@ -159,9 +159,6 @@ user_start(int argc, char *argv[])
 	/* start the FMU interface */
 	interface_init();
 
-	/* add a performance counter for the interface */
-	perf_counter_t interface_perf = perf_alloc(PC_ELAPSED, "interface");
-
 	/* add a performance counter for mixing */
 	perf_counter_t mixer_perf = perf_alloc(PC_ELAPSED, "mix");
 
@@ -203,11 +200,6 @@ user_start(int argc, char *argv[])
 		/* track the rate at which the loop is running */
 		perf_count(loop_perf);
 
-		/* kick the interface */
-		perf_begin(interface_perf);
-		interface_tick();
-		perf_end(interface_perf);
-
 		/* kick the mixer */
 		perf_begin(mixer_perf);
 		mixer_tick();
@@ -218,6 +210,7 @@ user_start(int argc, char *argv[])
 		controls_tick();
 		perf_end(controls_perf);
 
+#if 0
 		/* check for debug activity */
 		show_debug_messages();
 
@@ -234,6 +227,7 @@ user_start(int argc, char *argv[])
 				  (unsigned)minfo.mxordblk);
 			last_debug_time = hrt_absolute_time();
 		}
+#endif
 	}
 }
 

src/modules/px4iofirmware/serial.c

@@ -74,9 +74,6 @@ static DMA_HANDLE	rx_dma;
 static int		serial_interrupt(int irq, void *context);
 static void		dma_reset(void);
 
-/* if we spend this many ticks idle, reset the DMA */
-static unsigned		idle_ticks;
-
 static struct IOPacket	dma_packet;
 
 /* serial register accessors */
@@ -150,16 +147,6 @@ interface_init(void)
 	debug("serial init");
 }
 
-void
-interface_tick()
-{
-	/* XXX look for stuck/damaged DMA and reset? */
-	if (idle_ticks++ > 100) {
-		dma_reset();
-		idle_ticks = 0;
-	}
-}
-
 static void
 rx_handle_packet(void)
 {
@@ -230,9 +217,6 @@ rx_dma_callback(DMA_HANDLE handle, uint8_t status, void *arg)
 	/* disable UART DMA */
 	rCR3 &= ~(USART_CR3_DMAT | USART_CR3_DMAR);
 
-	/* reset the idle counter */
-	idle_ticks = 0;
-
 	/* handle the received packet */
 	rx_handle_packet();
 
@@ -308,6 +292,7 @@ serial_interrupt(int irq, void *context)
 
 			/* it was too short - possibly truncated */
 			perf_count(pc_badidle);
+			dma_reset();
 			return 0;
 		}
 
@@ -343,7 +328,8 @@ dma_reset(void)
 		sizeof(dma_packet),
 		DMA_CCR_MINC		|
 		DMA_CCR_PSIZE_8BITS	|
-		DMA_CCR_MSIZE_8BITS);
+		DMA_CCR_MSIZE_8BITS     |
+		DMA_CCR_PRIVERYHI);
 
 	/* start receive DMA ready for the next packet */
 	stm32_dmastart(rx_dma, rx_dma_callback, NULL, false);