summaryrefslogtreecommitdiff
path: root/include/linux/tty.h
diff options
context:
space:
mode:
authorPeter Hurley <peter@hurleysoftware.com>2016-04-10 03:53:20 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-04-30 19:26:55 +0300
commite4d38f334ad24f80229a8ebab26950de8e8f34d7 (patch)
tree700de742e06c9ef1df41d6d79b59a91d095abb4d /include/linux/tty.h
parent97ef38b8210d7459d4cb51668cdf3983772ac6b7 (diff)
downloadlinux-e4d38f334ad24f80229a8ebab26950de8e8f34d7.tar.xz
tty: Define ASYNC_ replacement bits
Prepare for relocating kernel private state bits out of tty_port::flags field; tty_port::flags field is not atomic and can become corrupted by concurrent updates. It also suffers from the complication of sharing in a userspace-visible field which must be masked. Define new tty_port::iflags field and new, substitute bit definitions for the former ASYNC_* flags. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include/linux/tty.h')
-rw-r--r--include/linux/tty.h16
1 files changed, 15 insertions, 1 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