userspace: clean up lm32-vuart

lm32-vuart was destroying the tty it was run into. And ctrl-C was not working (the initial message "press ctrl-A" was not really visible). This removes part of the cruft of the program. It also adds a little delay when no bytes are there to read from FPGA to releaf a little the load on the ARM CPU. Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

userspace: clean up lm32-vuart
lm32-vuart was destroying the tty it was run into. And ctrl-C was not working (the initial message "press ctrl-A" was not really visible). This removes part of the cruft of the program. It also adds a little delay when no bytes are there to read from FPGA to releaf a little the load on the ARM CPU. Signed-off-by: Alessandro Rubini <rubini@gnudd.com>
254c359b · Alessandro Rubini · c32915cd · 254c359b
Commit 254c359b authored Jul 15, 2015 by Alessandro Rubini
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Showing with 7 additions and 27 deletions

lm32-vuart.c userspace/tools/lm32-vuart.c +7 -27

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--- a/userspace/tools/lm32-vuart.c
+++ b/userspace/tools/lm32-vuart.c
@@ -38,18 +38,13 @@ int vuart_rx(char *buf, int size)
 	return n_rx;
 }

-static int transfer_byte(int from, int is_control) {
+static int transfer_byte(int from) {
 	char c;
 	int ret;
 	do {
 		ret = read(from, &c, 1);
 	} while (ret < 0 && errno == EINTR);
 	if(ret == 1) {
-		if(is_control) {
-			if(c == '\x01') { // C-a
-				return -1;
-			}
-		}
 		vuart_tx(&c, 1);
 	} else {
 		fprintf(stderr, "nothing to read. Port disconnected?\n");
@@ -59,25 +54,11 @@ static int transfer_byte(int from, int is_control) {
 }


-void term_main(int keep_term)
+void term_main(void)
 {
 	struct termios oldkey, newkey;
-	int need_exit = 0;
-
-	fprintf(stderr, "[press C-a to exit]\n");
-
-	if(!keep_term) {
-		tcgetattr(STDIN_FILENO,&oldkey);
-		newkey.c_cflag = B9600 | CS8 | CLOCAL | CREAD;
-		newkey.c_iflag = IGNPAR;
-		newkey.c_oflag = 0;
-		newkey.c_lflag = 0;
-		newkey.c_cc[VMIN]=1;
-		newkey.c_cc[VTIME]=0;
-		tcflush(STDIN_FILENO, TCIFLUSH);
-		tcsetattr(STDIN_FILENO,TCSANOW,&newkey);
-	}
-	while(!need_exit) {
+
+	while(1) {
 		fd_set fds;
 		int ret;
 		char rx;
@@ -91,23 +72,22 @@ void term_main(int keep_term)
 			perror("select");
 		} else if (ret > 0) {
 			if(FD_ISSET(STDIN_FILENO, &fds)) {
-				need_exit = transfer_byte(STDIN_FILENO, 1);
+				transfer_byte(STDIN_FILENO);
 			}
 		}

 		while((vuart_rx(&rx, 1)) == 1)
 			fprintf(stderr,"%c", rx);
+		usleep(1000); /* relief the CPU */
 	}

-	if(!keep_term)
-		tcsetattr(STDIN_FILENO,TCSANOW,&oldkey);
 }


 int main(void)
 {
 	shw_fpga_mmap_init();
-	term_main(0);
+	term_main();

 	return 0;
 }