2 files changed, 23 insertions, 2 deletions

diff --git a/include/linux/tty.h b/include/linux/tty.h
index 89f9c91b40f5..4e0dbda05180 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -228,7 +228,8 @@ struct tty_port {
         int                     count;          /* Usage count */
         wait_queue_head_t       open_wait;      /* Open waiters */
         wait_queue_head_t       delta_msr_wait; /* Modem status change */
-        unsigned long           flags;          /* TTY flags ASY_*/
+        unsigned long           flags;          /* User TTY flags ASYNC_ */
+        unsigned long           iflags;         /* Internal flags TTY_PORT_ */
         unsigned char           console:1,      /* port is a console */
                                 low_latency:1;  /* optional: tune for latency */
         struct mutex            mutex;          /* Locking */
@@ -242,6 +243,19 @@ struct tty_port {
         struct kref             kref;           /* Ref counter */
 };
 
+/* tty_port::iflags bits -- use atomic bit ops */
+#define TTY_PORT_INITIALIZED    0       /* device is initialized */
+#define TTY_PORT_SUSPENDED      1       /* device is suspended */
+#define TTY_PORT_ACTIVE         2       /* device is open */
+
+/*
+ * uart drivers: use the uart_port::status field and the UPSTAT_* defines
+ * for s/w-based flow control steering and carrier detection status
+ */
+#define TTY_PORT_CTS_FLOW       3       /* h/w flow control enabled */
+#define TTY_PORT_CHECK_CD       4       /* carrier detect enabled */
+
+
 /*
  * Where all of the state associated with a tty is kept while the tty
  * is open.  Since the termios state should be kept even if the tty
diff --git a/include/uapi/linux/tty_flags.h b/include/uapi/linux/tty_flags.h
index 072e41e45ee2..8e1a4365259f 100644
--- a/include/uapi/linux/tty_flags.h
+++ b/include/uapi/linux/tty_flags.h
@@ -32,7 +32,12 @@
 #define ASYNCB_MAGIC_MULTIPLIER 16 /* Use special CLK or divisor */
 #define ASYNCB_LAST_USER        16
 
-/* Internal flags used only by kernel */
+/*
+ * Internal flags used only by kernel (read-only)
+ *
+ * WARNING: These flags are no longer used and have been superceded by the
+ *          TTY_PORT_ flags in the iflags field (and not userspace-visible)
+ */
 #define ASYNCB_INITIALIZED      31 /* Serial port was initialized */
 #define ASYNCB_SUSPENDED        30 /* Serial port is suspended */
 #define ASYNCB_NORMAL_ACTIVE    29 /* Normal device is active */
@@ -44,6 +49,7 @@
 #define ASYNCB_CONS_FLOW        23 /* flow control for console  */
 #define ASYNCB_FIRST_KERNEL     22
 
+/* Masks */
 #define ASYNC_HUP_NOTIFY        (1U << ASYNCB_HUP_NOTIFY)
 #define ASYNC_SUSPENDED         (1U << ASYNCB_SUSPENDED)
 #define ASYNC_FOURPORT          (1U << ASYNCB_FOURPORT)
@@ -72,6 +78,7 @@
 #define ASYNC_SPD_WARP          (ASYNC_SPD_HI|ASYNC_SPD_SHI)
 #define ASYNC_SPD_MASK          (ASYNC_SPD_HI|ASYNC_SPD_VHI|ASYNC_SPD_SHI)
 
+/* These flags are no longer used (and were always masked from userspace) */
 #define ASYNC_INITIALIZED       (1U << ASYNCB_INITIALIZED)
 #define ASYNC_NORMAL_ACTIVE     (1U << ASYNCB_NORMAL_ACTIVE)
 #define ASYNC_BOOT_AUTOCONF     (1U << ASYNCB_BOOT_AUTOCONF)