Zolertia Z1: Direct memory access using UART.

cpu/msp430/f2xxx/msp430.c

@@ -32,6 +32,10 @@
 #include "contiki.h"
 #include "dev/watchdog.h"
 
+/* dco_required set to 1 will cause the CPU not to go into
+ *    sleep modes where the DCO clock stopped */
+int msp430_dco_required;
+
 #if defined(__MSP430__) && defined(__GNUC__)
 #define asmv(arg) __asm__ __volatile__ (arg)
 #endif
@@ -156,6 +160,26 @@ extern int _end;		/* Not in sys/unistd.h */
 static char *cur_break = (char *)&_end;
 #endif
 
+/*---------------------------------------------------------------------------*/
+/* add/remove_lpm_req - for requiring a specific LPM mode. currently Contiki */
+/* jumps to LPM3 to save power, but DMA will not work if DCO is not clocked  */
+/* so some modules might need to enter their LPM requirements                */
+/* NOTE: currently only works with LPM1 (e.g. DCO) requirements.             */
+/*---------------------------------------------------------------------------*/
+void
+msp430_add_lpm_req(int req)
+{
+  if(req <= MSP430_REQUIRE_LPM1) {
+    msp430_dco_required++;
+  }
+}
+void
+msp430_remove_lpm_req(int req)
+{
+  if(req <= MSP430_REQUIRE_LPM1) {
+    msp430_dco_required--;
+  }
+}
 void
 msp430_cpu_init(void)
 {
@@ -172,6 +196,7 @@ msp430_cpu_init(void)
     cur_break++;
   }
 #endif
+  msp430_dco_required = 0;
 }
 /*---------------------------------------------------------------------------*/
 
@@ -209,7 +234,8 @@ splhigh_(void)
 /* } */
 /*---------------------------------------------------------------------------*/
 #ifdef __IAR_SYSTEMS_ICC__
-int __low_level_init(void)
+int
+__low_level_init(void)
 {
   /* turn off watchdog so that C-init will run */
   WDTCTL = WDTPW + WDTHOLD;
@@ -224,7 +250,8 @@ int __low_level_init(void)
 #endif
 /*---------------------------------------------------------------------------*/
 void
-msp430_sync_dco(void) {
+msp430_sync_dco(void)
+{
   uint16_t oldcapture;
   int16_t diff;
   /* DELTA_2 assumes an ACLK of 32768 Hz */

cpu/msp430/f2xxx/uart0.c

@@ -51,6 +51,11 @@ static volatile uint8_t transmitting;
 #define TX_WITH_INTERRUPT 1
 #endif /* UART0_CONF_TX_WITH_INTERRUPT */
 
+#ifdef UART0_CONF_RX_WITH_DMA
+#define RX_WITH_DMA UART0_CONF_RX_WITH_DMA
+#else /* UART0_CONF_RX_WITH_DMA */
+#define RX_WITH_DMA 1
+#endif /* UART0_CONF_RX_WITH_DMA */
 
 #if TX_WITH_INTERRUPT
 #define TXBUFSIZE 64
@@ -59,6 +64,30 @@ static struct ringbuf txbuf;
 static uint8_t txbuf_data[TXBUFSIZE];
 #endif /* TX_WITH_INTERRUPT */
 
+#if RX_WITH_DMA
+#define RXBUFSIZE 128
+
+static uint8_t rxbuf[RXBUFSIZE];
+static uint16_t last_size;
+static struct ctimer rxdma_timer;
+
+static void
+handle_rxdma_timer(void *ptr)
+{
+  uint16_t size;
+  size = DMA0SZ; /* Note: loop requires that size is less or eq to RXBUFSIZE */
+  while(last_size != size) {
+    uart0_input_handler((unsigned char)rxbuf[RXBUFSIZE - last_size]);
+    last_size--;
+    if(last_size == 0) {
+      last_size = RXBUFSIZE;
+    }
+  }
+
+  ctimer_reset(&rxdma_timer);
+}
+#endif /* RX_WITH_DMA */
+
 /*---------------------------------------------------------------------------*/
 uint8_t
 uart0_active(void)
@@ -69,6 +98,9 @@ uart0_active(void)
 void
 uart0_set_input(int (*input)(unsigned char c))
 {
+#if RX_WITH_DMA /* This needs to be called after ctimer process is started */
+  ctimer_set(&rxdma_timer, CLOCK_SECOND / 64, handle_rxdma_timer, NULL);
+#endif
   uart0_input_handler = input;
 }
 /*---------------------------------------------------------------------------*/
@@ -135,8 +167,24 @@ uart0_init(unsigned long ubr)
   ringbuf_init(&txbuf, txbuf_data, sizeof(txbuf_data));
   IE2 |= UCA0TXIE;                        /* Enable UCA0 TX interrupt */
 #endif /* TX_WITH_INTERRUPT */
+
+#if RX_WITH_DMA
+  IE2 &= ~UCA0RXIE; /* disable USART0 RX interrupt  */
+  /* UART0_RX trigger */
+  DMACTL0 = DMA0TSEL_3;
+
+  /* source address = UCA0RXBUF */
+  DMA0SA = (unsigned int)&UCA0RXBUF;
+  DMA0DA = (unsigned int)&rxbuf;
+  DMA0SZ = RXBUFSIZE;
+  last_size = RXBUFSIZE;
+  DMA0CTL = DMADT_4 + DMASBDB + DMADSTINCR_3 + DMAEN + DMAREQ;
+
+  msp430_add_lpm_req(MSP430_REQUIRE_LPM1);
+#endif /* RX_WITH_DMA */
 }
 /*---------------------------------------------------------------------------*/
+#if !RX_WITH_DMA
 ISR(USCIAB0RX, uart0_rx_interrupt)
 {
   uint8_t c;
@@ -154,6 +202,7 @@ ISR(USCIAB0RX, uart0_rx_interrupt)
   }
   ENERGEST_OFF(ENERGEST_TYPE_IRQ);
 }
+#endif /* !RX_WITH_DMA */
 /*---------------------------------------------------------------------------*/
 #if TX_WITH_INTERRUPT
 ISR(USCIAB0TX, uart0_tx_interrupt)

platform/z1/contiki-conf.h

@@ -31,7 +31,6 @@
 #ifndef CONTIKI_CONF_H
 #define CONTIKI_CONF_H
 
-
 #include "platform-conf.h"
 
 #define XMAC_CONF_COMPOWER          1
@@ -60,7 +59,6 @@
 
 #define QUEUEBUF_CONF_NUM                4
 
-
 #else /* NETSTACK_CONF_WITH_IPV6 */
 
 /* Network setup for non-IPv6 (rime). */
@@ -108,7 +106,6 @@
 #define SHELL_VARS_CONF_RAM_BEGIN 0x1100
 #define SHELL_VARS_CONF_RAM_END 0x2000
 
-
 #define CFS_CONF_OFFSET_TYPE  long
 
 #define PROFILE_CONF_ON 0
@@ -127,8 +124,9 @@
 #define PROCESS_CONF_STATS 1
 /*#define PROCESS_CONF_FASTPOLL    4*/
 
+#define UART0_CONF_TX_WITH_INTERRUPT 0 /* So far, printfs without interrupt. */
 
-#define UART0_CONF_TX_WITH_INTERRUPT 0 // So far, printfs without interrupt.
+#define UART0_CONF_RX_WITH_DMA 0
 
 #ifdef NETSTACK_CONF_WITH_IPV6
 
@@ -186,11 +184,8 @@
 
 #define UIP_CONF_TCP_SPLIT       0
 
-
 #ifdef PROJECT_CONF_H
 #include PROJECT_CONF_H
 #endif /* PROJECT_CONF_H */
 
-
-
 #endif /* CONTIKI_CONF_H */