serial: Move tcdrain implementation from drivers/serial to libc

Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>

drivers/serial/Make.defs

@@ -36,12 +36,6 @@ ifeq ($(CONFIG_RPMSG_UART),y)
   CSRCS += uart_rpmsg.c
 endif
 
-# termios support
-
-ifeq ($(CONFIG_SERIAL_TERMIOS),y)
-  CSRCS += tcdrain.c
-endif
-
 # Pseudo-terminal support
 
 ifeq ($(CONFIG_PSEUDOTERM),y)

drivers/serial/serial.c

@@ -41,6 +41,7 @@
 #include <nuttx/sched.h>
 #include <nuttx/signal.h>
 #include <nuttx/fs/fs.h>
+#include <nuttx/cancelpt.h>
 #include <nuttx/serial/serial.h>
 #include <nuttx/fs/ioctl.h>
 #include <nuttx/power/pm.h>
@@ -87,7 +88,8 @@ static int     uart_putxmitchar(FAR uart_dev_t *dev, int ch,
 static inline ssize_t uart_irqwrite(FAR uart_dev_t *dev,
                                     FAR const char *buffer,
                                     size_t buflen);
-static int     uart_tcdrain(FAR uart_dev_t *dev, clock_t timeout);
+static int     uart_tcdrain(FAR uart_dev_t *dev,
+                            bool cancelable, clock_t timeout);
 
 /* Character driver methods */
 
@@ -397,10 +399,25 @@ static inline ssize_t uart_irqwrite(FAR uart_dev_t *dev,
  *
  ****************************************************************************/
 
-static int uart_tcdrain(FAR uart_dev_t *dev, clock_t timeout)
+static int uart_tcdrain(FAR uart_dev_t *dev,
+                        bool cancelable, clock_t timeout)
 {
   int ret;
 
+  /* tcdrain is a cancellation point */
+
+  if (cancelable && enter_cancellation_point())
+    {
+#ifdef CONFIG_CANCELLATION_POINTS
+      /* If there is a pending cancellation, then do not perform
+       * the wait.  Exit now with ECANCELED.
+       */
+
+      leave_cancellation_point();
+      return -ECANCELED;
+#endif
+    }
+
   /* Get exclusive access to the to dev->tmit.  We cannot permit new data to
    * be written while we are trying to flush the old data.
    *
@@ -503,6 +520,11 @@ static int uart_tcdrain(FAR uart_dev_t *dev, clock_t timeout)
       uart_givesem(&dev->xmit.sem);
     }
 
+  if (cancelable)
+    {
+      leave_cancellation_point();
+    }
+
   return ret;
 }
 
@@ -661,7 +683,7 @@ static int uart_close(FAR struct file *filep)
     {
       /* Now we wait for the transmit buffer(s) to clear */
 
-      uart_tcdrain(dev, 4 * TICK_PER_SEC);
+      uart_tcdrain(dev, false, 4 * TICK_PER_SEC);
     }
 
   /* Free the IRQ and disable the UART */
@@ -1366,7 +1388,7 @@ static int uart_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
 
           case TCDRN:
             {
-              ret = uart_tcdrain(dev, 10 * TICK_PER_SEC);
+              ret = uart_tcdrain(dev, true, 10 * TICK_PER_SEC);
             }
             break;
 #endif

include/sys/syscall_lookup.h

@@ -223,9 +223,6 @@ SYSCALL_LOOKUP(pwrite,                     4)
   SYSCALL_LOOKUP(timerfd_settime,          4)
   SYSCALL_LOOKUP(timerfd_gettime,          2)
 #endif
-#ifdef CONFIG_SERIAL_TERMIOS
-  SYSCALL_LOOKUP(tcdrain,                  1)
-#endif
 
 /* Board support */
 

libs/libc/termios/Make.defs

@@ -26,7 +26,7 @@ ifeq ($(CONFIG_SERIAL_TERMIOS),y)
 # Add the termios C files to the build
 
 CSRCS += lib_cfspeed.c lib_cfmakeraw.c lib_isatty.c lib_tcflush.c
-CSRCS += lib_tcflow.c lib_tcgetattr.c lib_tcsetattr.c
+CSRCS += lib_tcdrain.c lib_tcflow.c lib_tcgetattr.c lib_tcsetattr.c
 CSRCS += lib_ttyname.c lib_ttynamer.c
 
 # Add the termios directory to the build

libs/libc/termios/lib_tcdrain.c

@@ -1,5 +1,5 @@
 /****************************************************************************
- * drivers/serial/tcdrain.c
+ * libs/libc/termios/lib_tcdrain.c
  *
  * Licensed to the Apache Software Foundation (ASF) under one or more
  * contributor license agreements.  See the NOTICE file distributed with
@@ -29,7 +29,6 @@
 #include <termios.h>
 #include <errno.h>
 
-#include <nuttx/cancelpt.h>
 #include <nuttx/serial/tioctl.h>
 
 /****************************************************************************
@@ -54,33 +53,5 @@
 
 int tcdrain(int fd)
 {
-  int ret;
-
-  /* tcdrain is a cancellation point */
-
-  if (enter_cancellation_point())
-    {
-#ifdef CONFIG_CANCELLATION_POINTS
-      /* If there is a pending cancellation, then do not perform
-       * the wait.  Exit now with ECANCELED.
-       */
-
-      set_errno(ECANCELED);
-      leave_cancellation_point();
-      return ERROR;
-#endif
-    }
-
-  /* Perform the TCDRM IOCTL command.  It is safe to use the file descriptor
-   * in this context because we are executing on the calling application's
-   * thread.
-   *
-   * NOTE: ioctl() will set the errno variable and return ERROR if any error
-   * occurs.
-   */
-
-  ret = ioctl(fd, TCDRN, (unsigned long)0);
-
-  leave_cancellation_point();
-  return ret;
+  return ioctl(fd, TCDRN, (unsigned long)0);
 }

syscall/syscall.csv

@@ -177,7 +177,6 @@
 "task_setcanceltype","sched.h","defined(CONFIG_CANCELLATION_POINTS)","int","int","FAR int *"
 "task_spawn","nuttx/spawn.h","!defined(CONFIG_BUILD_KERNEL)","int","FAR const char *","main_t","FAR const posix_spawn_file_actions_t *","FAR const posix_spawnattr_t *","FAR char * const []|FAR char * const *","FAR char * const []|FAR char * const *"
 "task_testcancel","pthread.h","defined(CONFIG_CANCELLATION_POINTS)","void"
-"tcdrain","termios.h","defined(CONFIG_SERIAL_TERMIOS)","int","int"
 "telldir","dirent.h","","off_t","FAR DIR *"
 "timer_create","time.h","!defined(CONFIG_DISABLE_POSIX_TIMERS)","int","clockid_t","FAR struct sigevent *","FAR timer_t *"
 "timer_delete","time.h","!defined(CONFIG_DISABLE_POSIX_TIMERS)","int","timer_t"