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authorMaxime Ripard <maxime@cerno.tech>2021-09-14 09:25:30 +0200
committerMaxime Ripard <maxime@cerno.tech>2021-09-14 09:25:30 +0200
commit2f76520561d01a5f37e6d6ed2c2e441b6a355a96 (patch)
tree692f210145f35ec2621e2015d788267f25e673cb /include/linux/tty_buffer.h
parent617d5b34f22c66fe9fc9f150be27f5de1b87ca15 (diff)
parent6880fa6c56601bb8ed59df6c30fd390cc5f6dd8f (diff)
Merge drm/drm-next into drm-misc-next
Kickstart new drm-misc-next cycle. Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Diffstat (limited to 'include/linux/tty_buffer.h')
-rw-r--r--include/linux/tty_buffer.h59
1 files changed, 59 insertions, 0 deletions
diff --git a/include/linux/tty_buffer.h b/include/linux/tty_buffer.h
new file mode 100644
index 000000000000..3b9d77604291
--- /dev/null
+++ b/include/linux/tty_buffer.h
@@ -0,0 +1,59 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_TTY_BUFFER_H
+#define _LINUX_TTY_BUFFER_H
+
+#include <linux/atomic.h>
+#include <linux/llist.h>
+#include <linux/mutex.h>
+#include <linux/workqueue.h>
+
+struct tty_buffer {
+ union {
+ struct tty_buffer *next;
+ struct llist_node free;
+ };
+ int used;
+ int size;
+ int commit;
+ int read;
+ int flags;
+ /* Data points here */
+ unsigned long data[];
+};
+
+/* Values for .flags field of tty_buffer */
+#define TTYB_NORMAL 1 /* buffer has no flags buffer */
+
+static inline unsigned char *char_buf_ptr(struct tty_buffer *b, int ofs)
+{
+ return ((unsigned char *)b->data) + ofs;
+}
+
+static inline char *flag_buf_ptr(struct tty_buffer *b, int ofs)
+{
+ return (char *)char_buf_ptr(b, ofs) + b->size;
+}
+
+struct tty_bufhead {
+ struct tty_buffer *head; /* Queue head */
+ struct work_struct work;
+ struct mutex lock;
+ atomic_t priority;
+ struct tty_buffer sentinel;
+ struct llist_head free; /* Free queue head */
+ atomic_t mem_used; /* In-use buffers excluding free list */
+ int mem_limit;
+ struct tty_buffer *tail; /* Active buffer */
+};
+
+/*
+ * When a break, frame error, or parity error happens, these codes are
+ * stuffed into the flags buffer.
+ */
+#define TTY_NORMAL 0
+#define TTY_BREAK 1
+#define TTY_FRAME 2
+#define TTY_PARITY 3
+#define TTY_OVERRUN 4
+
+#endif