Options to extend mc1322x fifo to RAM buffer, or use hardware flow control with tunslip6.

cpu/mc1322x/lib/include/uart1.h

@@ -70,9 +70,29 @@
 #define UART2_UCTS       ((volatile uint32_t *) ( UART2_BASE + UCTS   ))
 #define UART2_UBRCNT     ((volatile uint32_t *) ( UART2_BASE + UBRCNT ))
 
-extern volatile uint32_t  u1_head, u1_tail;
+/* The mc1322x has a 32 byte hardware FIFO for transmitted characters.
+ * Currently it is always filled from a larger RAM buffer. It would be
+ * possible to eliminate that overhead by filling directly from a chain
+ * of data buffer pointers, but printf's would be not so easy.
+ */
+#define UART1_TX_BUFFERSIZE 1024
+extern volatile uint32_t  u1_tx_head, u1_tx_tail;
 void uart1_putc(char c);
+
+/* The mc1322x has a 32 byte hardware FIFO for received characters.
+ * If a larger rx buffersize is specified the FIFO will be extended into RAM.
+ * RAM transfers will occur on interrupt when the FIFO is nearly full.
+ * If a smaller buffersize is specified hardware flow control will be
+ * initiated at that FIFO level.
+ * Set to 32 for no flow control or RAM buffer.
+ */
+#define UART1_RX_BUFFERSIZE 128
+#if UART1_RX_BUFFERSIZE > 32
+extern volatile uint32_t  u1_rx_head, u1_rx_tail;
+#define uart1_can_get() ((u1_rx_head!=u1_rx_tail) || (*UART1_URXCON > 0))
+#else
 #define uart1_can_get() (*UART1_URXCON > 0)
+#endif
 uint8_t uart1_getc(void);
 
 

cpu/mc1322x/lib/uart1.c

@@ -36,43 +36,91 @@
 #include <mc1322x.h>
 #include <stdint.h>
 
-volatile char u1_tx_buf[1024];
+volatile char u1_tx_buf[UART1_TX_BUFFERSIZE];
-volatile uint32_t u1_head, u1_tail;
+volatile uint32_t u1_tx_head, u1_tx_tail;
+
+#if UART1_RX_BUFFERSIZE > 32
+volatile char u1_rx_buf[UART1_RX_BUFFERSIZE-32];
+volatile uint32_t u1_rx_head, u1_rx_tail;
+#endif
 
 void uart1_isr(void) {
- 	while( *UART1_UTXCON != 0 ) {
+
-		if (u1_head == u1_tail) {
+#if UART1_RX_BUFFERSIZE > 32
-			disable_irq(UART1);
+  if (*UART1_USTAT & ( 1 << 6)) {   //receive interrupt
+ 	while( *UART1_URXCON != 0 ) {   //flush the hardware fifo into the software buffer
+        uint32_t u1_rx_tail_next;
+        u1_rx_tail_next = u1_rx_tail+1;		
+		if (u1_rx_tail_next >= sizeof(u1_rx_buf))
+			u1_rx_tail_next = 0;
+        if (u1_rx_head != u1_rx_tail_next) {
+		    u1_rx_buf[u1_rx_tail]= *UART1_UDATA;       
+		    u1_rx_tail =  u1_rx_tail_next;
+        }
+	}
     return;
   }
-		*UART1_UDATA = u1_tx_buf[u1_tail];
+#endif
-		u1_tail++;		
+
-		if (u1_tail >= sizeof(u1_tx_buf))
+ 	while( *UART1_UTXCON != 0 ) {
-			u1_tail = 0;
+		if (u1_tx_head == u1_tx_tail) {
+#if UART1_RX_BUFFERSIZE > 32
+            *UART1_UCON |= (1 << 13); /*disable tx interrupt */
+#else
+			disable_irq(UART1);
+#endif
+			return;
+		}
+
+		*UART1_UDATA = u1_tx_buf[u1_tx_tail];
+		u1_tx_tail++;		
+		if (u1_tx_tail >= sizeof(u1_tx_buf))
+			u1_tx_tail = 0;
 	}
 }
 
 void uart1_putc(char c) {
 	/* disable UART1 since */
-	/* UART1 isr modifies u1_head and u1_tail */ 
+	/* UART1 isr modifies u1_tx_head and u1_tx_tail */ 
+#if UART1_RX_BUFFERSIZE > 32
+            *UART1_UCON |= (1 << 13); /*disable tx interrupt */
+#else
 			disable_irq(UART1);
+#endif
 
-	if( (u1_head == u1_tail) &&
+	if( (u1_tx_head == u1_tx_tail) &&
 	    (*UART1_UTXCON != 0)) {
 		*UART1_UDATA = c;
 	} else {
-		u1_tx_buf[u1_head] = c;
+		u1_tx_buf[u1_tx_head] = c;
-		u1_head += 1;
+		u1_tx_head += 1;
-		if (u1_head >= sizeof(u1_tx_buf))
+		if (u1_tx_head >= sizeof(u1_tx_buf))
-			u1_head = 0;
+			u1_tx_head = 0;
-		if (u1_head == u1_tail) { /* drop chars when no room */
+		if (u1_tx_head == u1_tx_tail) { /* drop chars when no room */
-			if (u1_head) { u1_head -=1; } else { u1_head = sizeof(u1_tx_buf); }
+			if (u1_tx_head) { u1_tx_head -=1; } else { u1_tx_head = sizeof(u1_tx_buf); }
 		}
+
+#if UART1_RX_BUFFERSIZE > 32
+        *UART1_UCON &= ~(1 << 13); /*enable tx interrupt */
+#else
 		enable_irq(UART1);
+#endif
+
 	}
 }
 
 uint8_t uart1_getc(void) {
+#if UART1_RX_BUFFERSIZE > 32
+/* First pull from the ram buffer */
+uint8_t c=0;
+  if (u1_rx_head != u1_rx_tail) {
+    c = u1_rx_buf[u1_rx_head++];
+    if (u1_rx_head >= sizeof(u1_rx_buf))
+        u1_rx_head=0;
+    return c;
+  }
+#endif
+/* Then pull from the hardware fifo */
 	while(uart1_can_get() == 0) { continue; }
 	return *UART1_UDATA;
 }

cpu/mc1322x/src/default_lowlevel.c

@@ -63,18 +63,27 @@ void uart1_init(uint16_t inc, uint16_t mod, uint8_t samp) {
 	/* you must enable the peripheral first BEFORE setting the function in GPIO_FUNC_SEL */
 	/* From the datasheet: "The peripheral function will control operation of the pad IF */
 	/* THE PERIPHERAL IS ENABLED. */
-	*UART1_UCON = (1 << 0) | (1 << 1); /* enable receive, transmit */
+
+#if UART1_RX_BUFFERSIZE > 32
+	*UART1_UCON = (1 << 0) | (1 << 1) ;	/* enable receive, transmit, and both interrupts */
+	*UART1_URXCON = 30;					/* interrupt when fifo is nearly full */
+	u1_rx_head = 0; u1_rx_tail = 0;
+#elif UART1_RX_BUFFERSIZE < 32			/* enable receive, transmit, flow control, disable rx interrupt */
+	*UART1_UCON = (1 << 0) | (1 << 1) | (1 << 12) | (1 << 14); 
+	*UART1_UCTS = UART1_RX_BUFFERSIZE;  /* drop cts when tx buffer at trigger level */
+	*GPIO_FUNC_SEL1 = ( (0x01 << (0*2)) | (0x01 << (1*2)) ); /* set GPIO17-16 to UART1 CTS and RTS */
+#else 
+	*UART1_UCON = (1 << 0) | (1 << 1) | (1 << 14); /* enable receive, transmit, disable rx interrupt */
+#endif
+
 	if(samp == UCON_SAMP_16X) 
 		set_bit(*UART1_UCON,UCON_SAMP);
 	*GPIO_FUNC_SEL0 = ( (0x01 << (14*2)) | (0x01 << (15*2)) ); /* set GPIO15-14 to UART (UART1 TX and RX)*/
 
 	/* interrupt when there are this number or more bytes free in the TX buffer*/
 	*UART1_UTXCON = 16;
+    u1_tx_head = 0; u1_tx_tail = 0;
 
-	u1_head = 0; u1_tail = 0;
-
-	/* tx and rx interrupts are enabled in the UART by default */
-	/* see status register bits 13 and 14 */
 	/* enable UART1 interrupts in the interrupt controller */
 	enable_irq(UART1);
 }

platform/redbee-econotag/contiki-mc1322x-main.c

@@ -48,6 +48,7 @@
 #include "lib/random.h"
 #include "net/netstack.h"
 #include "net/mac/frame802154.h"
+#include "lib/include/uart1.h"
 
 #if WITH_UIP6
 #include "net/sicslowpan.h"
@@ -490,7 +491,6 @@ main(void)
 	  cop_service();
 #endif
 
-	  /* TODO: replace this with a uart rx interrupt */
 	  if(uart1_input_handler != NULL) {
 		  if(uart1_can_get()) {
 			  uart1_input_handler(uart1_getc());

tools/tunslip6.c

@@ -60,7 +60,7 @@ const char *netmask;
 int slipfd = 0;
 uint16_t basedelay=0,delaymsec=0;
 uint32_t startsec,startmsec,delaystartsec,delaystartmsec;
-int timestamp = 0;
+int timestamp = 0, flowcontrol=0;
 
 int ssystem(const char *fmt, ...)
      __attribute__((__format__ (__printf__, 1, 2)));
@@ -172,7 +172,7 @@ serial_to_tun(FILE *inslip, int outfd)
   if(inbufptr >= sizeof(uip.inbuf)) {
      inbufptr = 0;
      if(timestamp) stamptime();
-     fprintf(stderr, "*** dropping too large packet\n");
+     fprintf(stderr, "*** dropping large %d byte packet\n",inbufptr);
   }
   ret = fread(&c, 1, 1, inslip);
 #ifdef linux
@@ -459,6 +459,9 @@ stty_telos(int fd)
   /* Nonblocking read. */
   tty.c_cc[VTIME] = 0;
   tty.c_cc[VMIN] = 0;
+  if (flowcontrol)
+    tty.c_cflag |= CRTSCTS;
+  else
     tty.c_cflag &= ~CRTSCTS;
   tty.c_cflag &= ~HUPCL;
   tty.c_cflag &= ~CLOCAL;
@@ -616,12 +619,16 @@ main(int argc, char **argv)
   prog = argv[0];
   setvbuf(stdout, NULL, _IOLBF, 0); /* Line buffered output. */
 
-  while((c = getopt(argc, argv, "B:D:Lhs:t:v::d::a:p:T")) != -1) {
+  while((c = getopt(argc, argv, "B:H:D:Lhs:t:v::d::a:p:T")) != -1) {
     switch(c) {
     case 'B':
       baudrate = atoi(optarg);
       break;
 
+    case 'H':
+      flowcontrol=1;
+      break;
+ 
     case 'L':
       timestamp=1;
       break;
@@ -671,6 +678,7 @@ fprintf(stderr,"usage:  %s [options] ipaddress\n", prog);
 fprintf(stderr,"example: tunslip6 -L -v2 -s ttyUSB1 aaaa::1/64\n");
 fprintf(stderr,"Options are:\n");
 fprintf(stderr," -B baudrate    9600,19200,38400,57600,115200 (default)\n");
+fprintf(stderr," -H             Hardware CTS/RTS flow control (default disabled)\n");
 fprintf(stderr," -L             Log output format (adds time stamps)\n");
 fprintf(stderr," -s siodev      Serial device (default /dev/ttyUSB0)\n");
 fprintf(stderr," -T             Make tap interface (default is tun interface)\n");
@@ -696,7 +704,7 @@ exit(1);
   argv += (optind - 1);
 
   if(argc != 2 && argc != 3) {
-    err(1, "usage: %s [-B baudrate] [-L] [-s siodev] [-t tundev] [-T] [-v verbosity] [-d delay] [-a serveraddress] [-p serverport] ipaddress", prog);
+    err(1, "usage: %s [-B baudrate] [-H] [-L] [-s siodev] [-t tundev] [-T] [-v verbosity] [-d delay] [-a serveraddress] [-p serverport] ipaddress", prog);
   }
   ipaddr = argv[1];