rs485echo: Support all baudrates using termios2 ioctl directly from kernel header

The kernel has support for setting the baudrate as integer using BOTHER
as id with the termios2 struct. It seems that this is not yet supported
in the libc, so we are using kernel headers directly.

testcases/rs485echo/Makefile

@@ -4,16 +4,16 @@ SYSROOT ?= SDKTARGETSYSROOT
 
 top_srcdir	?= $(SYSROOT)/usr
 
-CFLAGS+=    -I$(top_srcdir)/include -Wall -Werror
+CFLAGS+=    -I$(top_srcdir)/include -I. -Wall -Werror
 LOADLIBES+= -L$(top_srcdir)/lib -lltp
 
-SRCS=$(TARGET).c
+SRCS=$(TARGET).c termios2.c
 
 all: $(TARGET)
 
 $(TARGET): $(SRCS)
 	@mkdir -p ../bin
-	@$(CC) $(CFLAGS) $(LDFLAGS) $< $(LOADLIBES) -o ../bin/$@
+	@$(CC) $(CFLAGS) $(LDFLAGS) $^ $(LOADLIBES) -o ../bin/$@
 
 clean:
 	rm -f $(TARGET) *.o *.bak *~

testcases/rs485echo/rs485echo.c

@@ -52,10 +52,12 @@
 #include <asm/ioctls.h>
 #include <linux/serial.h>
 
+
 /* Harness Specific Include Files. */
 #include "old/test.h"
 
 #include "config.h"
+#include "termios2.h"
 
 /* Local Defines */
 #if !defined(TRUE) && !defined(FALSE)
@@ -227,7 +229,7 @@ void tst_dump_data(const char * pre, const char * data, int len)
 void
 setup()
 {
-	int i;
+	int i, ret;
 	struct serial_rs485 rs485;
 	speed_t baud = B0;
 
@@ -242,7 +244,7 @@ setup()
 	}
 	if (baud == B0)
 		//tst_brkm(TBROK, cleanup, "Baud rate not supported (%d)", baudrate);
-		tst_resm(TWARN, "Baud rate is non standard, tryin anyway (%d)", baudrate);
+		tst_resm(TWARN, "Baud rate is non standard, trying anyway (%d)", baudrate);
 
 	if (!echo_mode)
 	{
@@ -305,37 +307,8 @@ setup()
 	memcpy(termios.c_cc, ttydefchars, MIN(sizeof(termios.c_cc), sizeof(ttydefchars)));
 
 	// Set Speed into termios structure
-	if( baud == B0 )
+	if( baud != B0 )
 	{
-		struct serial_struct serial;
-		int baudrate_rounded;
-
-		// Non standard baudrate
-		// https://stackoverflow.com/questions/19440268/how-to-set-a-non-standard-baudrate-on-a-serial-port-device-on-linux
-		// drivers/tty/serial/serial_core.c +491
-		if (cfsetspeed (&termios, B38400)) {
-			tst_brkm(TBROK, cleanup,
-				"Can't set baud rate.  Error:%d, %s\n",
-				errno, strerror(errno));
-		}
-		if (ioctl(fd, TIOCGSERIAL, &serial)){
-			tst_brkm(TBROK, cleanup,
-				"Failed to do TIOCGSERIAL IOCTL.  Error:%d, %s\n",
-				errno, strerror(errno));
-		}
-
-		serial.flags &= ~ASYNC_SPD_MASK;
-		serial.flags |= ASYNC_SPD_CUST;
-		serial.custom_divisor = serial.baud_base / baudrate;
-		baudrate_rounded = serial.baud_base / serial.custom_divisor;
-		if( baudrate != baudrate_rounded)
-			tst_resm(TWARN, "Selected closest baudrate %d.\n", baudrate_rounded);
-		if (ioctl(fd, TIOCSSERIAL, &serial)){
-			tst_brkm(TBROK, cleanup,
-				"Can't set baud rate.  Error:%d, %s\n",
-				errno, strerror(errno));
-		}
-	}else{
 		if (cfsetspeed (&termios, baud)) {
 			tst_brkm(TBROK, cleanup,
 				"Can't set baud rate.  Error:%d, %s\n",
@@ -358,10 +331,17 @@ setup()
 	}
 
 	// set new attribute
-	if (tcsetattr (fd, TCSANOW, &termios)) {
-		tst_brkm(TBROK, cleanup,
-			"Can't set device configuration.  Error:%d, %s\n",
-			errno, strerror(errno));
+	if( baud == B0 ) // Non standard baudrate
+	{
+		ret = tty_set_arbitrary_speed(fd, baudrate, &termios);
+		if( ret < 0)
+			tst_brkm(TBROK, cleanup, "Can't set baud rate %d.\n", baudrate);
+	}else{
+		if (tcsetattr (fd, TCSANOW, &termios)) {
+			tst_brkm(TBROK, cleanup,
+				"Can't set device configuration.  Error:%d, %s\n",
+				errno, strerror(errno));
+		}
 	}
 
 	return;
@@ -447,6 +427,7 @@ main(int   argc,    /* number of command line parameters                      */
 	char *str_device_name, *str_repetitions, *str_bytes, *str_timeout,
 		*str_baudrate, *str_delaytime, *str_receive_sleep, *str_fake_data_len,
 		*str_fake_data;
+	int ret;
 
 	option_t options[] = {
 		{"b:", &opt_bytes, &str_bytes},
@@ -571,7 +552,9 @@ main(int   argc,    /* number of command line parameters                      */
 					 cycle_count+1, message->data, message->length > 1000 ? "[...]" : "");
 
 			// Send message
-			write(fd, (char*)message, size_of_message);
+			ret = write(fd, (char*)message, size_of_message);
+			if( ret < 0 )
+				tst_brkm(TBROK, cleanup, "Failed to write bytes (%d)", errno);
 
 			// Get current time for measuring timeout
 			gettimeofday(&start, NULL);
@@ -740,7 +723,9 @@ main(int   argc,    /* number of command line parameters                      */
 						usleep(send_delay);
 						tst_resm(TINFO, "Received data: %.1000s%s", received_data,
 									data_length > 1000 ? "[...]" : "");
-						write(fd, received_data, data_length);
+						ret = write(fd, received_data, data_length);
+						if( ret < 0 )
+							tst_brkm(TBROK, cleanup, "Failed to write bytes (%d)", errno);
 						tst_resm(TINFO, "Echoed data back to sender");
 						free(received_data);
 						received_data = NULL;

testcases/rs485echo/termios2.c

+/* as these includes colide with the ones used in the rs485echo file
+   this function is in its own file.
+   The 'termios2' struct seems not available and used in the standard headers
+   so we use it directly from the kernel headers.
+   */
+
+#include <sys/ioctl.h>
+#include "/usr/include/asm-generic/termbits.h"
+#include "/usr/include/asm-generic/ioctls.h"
+
+
+int tty_set_arbitrary_speed( int fd, int speed, struct termios * termios)
+{
+	 struct termios2 to;
+	 int r, i;
+
+	 r = ioctl(fd, TCGETS2, &to);  
+	 if (r) return -1;
+
+	 to.c_iflag = termios->c_iflag;
+	 to.c_oflag = termios->c_oflag;
+	 to.c_cflag = termios->c_cflag;
+	 to.c_lflag = termios->c_lflag;
+	 to.c_line = termios->c_line;
+	 for( i = 0; i < NCCS; i++)
+		 to.c_cc[i] = termios->c_cc[i];
+
+	 speed_t spd = speed;
+	 to.c_ispeed = to.c_ospeed = spd;
+	 to.c_cflag &= ~CBAUD;
+	 to.c_cflag |= BOTHER;
+	 r = ioctl(fd, TCSETSF2, &to);  
+	 if (r) return -1;
+	 return 0;
+}

testcases/rs485echo/termios2.h

+
+int tty_set_arbitrary_speed( int fd, int speed, struct termios * termios);