add cmmb moudle file directory.

[firefly-linux-kernel-4.4.55.git] / drivers / cmmb / cmmb_ringbuffer.h

diff --git a/drivers/cmmb/cmmb_ringbuffer.h b/drivers/cmmb/cmmb_ringbuffer.h
new file mode 100755 (executable)
index 0000000..fea0079
--- /dev/null
+++ b/drivers/cmmb/cmmb_ringbuffer.h
@@ -0,0 +1,138 @@
+/*
+ *
+ * dvb_ringbuffer.h: ring buffer implementation for the dvb driver
+ *
+ * Copyright (C) 2003 Oliver Endriss
+ * Copyright (C) 2004 Andrew de Quincey
+ *
+ * based on code originally found in av7110.c & dvb_ci.c:
+ * Copyright (C) 1999-2003 Ralph Metzler & Marcus Metzler
+ *                         for convergence integrated media GmbH
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * as published by the Free Software Foundation; either version 2.1
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+#ifndef _DVB_RINGBUFFER_H_1
+#define _DVB_RINGBUFFER_H_1
+
+#include <linux/spinlock.h>
+#include <linux/wait.h>
+
+struct dvb_ringbuffer {
+       u8               *data;
+       ssize_t           size;
+       ssize_t           pread;
+       ssize_t           pwrite;
+       int               error;
+    volatile int      condition;
+       wait_queue_head_t queue;
+       spinlock_t        lock;
+};
+
+#define DVB_RINGBUFFER_PKTHDRSIZE 3
+
+
+/*
+** Notes:
+** ------
+** (1) For performance reasons read and write routines don't check buffer sizes
+**     and/or number of bytes free/available. This has to be done before these
+**     routines are called. For example:
+**
+**     *** write <buflen> bytes ***
+**     free = dvb_ringbuffer_free(rbuf);
+**     if (free >= buflen)
+**         count = dvb_ringbuffer_write(rbuf, buffer, buflen);
+**     else
+**         ...
+**
+**     *** read min. 1000, max. <bufsize> bytes ***
+**     avail = dvb_ringbuffer_avail(rbuf);
+**     if (avail >= 1000)
+**         count = dvb_ringbuffer_read(rbuf, buffer, min(avail, bufsize), 0);
+**     else
+**         ...
+**
+** (2) If there is exactly one reader and one writer, there is no need
+**     to lock read or write operations.
+**     Two or more readers must be locked against each other.
+**     Flushing the buffer counts as a read operation.
+**     Two or more writers must be locked against each other.
+*/
+
+/* initialize ring buffer, lock and queue */
+extern void cmmb_ringbuffer_init(struct dvb_ringbuffer *rbuf, void *data, size_t len);
+
+/* test whether buffer is empty */
+extern int cmmb_ringbuffer_empty(struct dvb_ringbuffer *rbuf);
+
+/* return the number of free bytes in the buffer */
+extern ssize_t cmmb_ringbuffer_free(struct dvb_ringbuffer *rbuf);
+
+/* return the number of bytes waiting in the buffer */
+extern ssize_t cmmb_ringbuffer_avail(struct dvb_ringbuffer *rbuf);
+
+
+/* read routines & macros */
+/* ---------------------- */
+/* flush buffer */
+extern void cmmb_ringbuffer_flush(struct dvb_ringbuffer *rbuf);
+
+/* flush buffer protected by spinlock and wake-up waiting task(s) */
+extern void cmmb_ringbuffer_flush_spinlock_wakeup(struct dvb_ringbuffer *rbuf);
+
+/* peek at byte <offs> in the buffer */
+#define DVB_RINGBUFFER_PEEK(rbuf,offs) \
+                       (rbuf)->data[((rbuf)->pread+(offs))%(rbuf)->size]
+
+/* advance read ptr by <num> bytes */
+#define DVB_RINGBUFFER_SKIP(rbuf,num)  \
+                       (rbuf)->pread=((rbuf)->pread+(num))%(rbuf)->size
+
+/*
+** read <len> bytes from ring buffer into <buf>
+** <usermem> specifies whether <buf> resides in user space
+** returns number of bytes transferred or -EFAULT
+*/
+extern ssize_t cmmb_ringbuffer_read(struct dvb_ringbuffer *rbuf, u8 *buf,
+                                  size_t len, int usermem);
+
+
+/* write routines & macros */
+/* ----------------------- */
+/* write single byte to ring buffer */
+#define DVB_RINGBUFFER_WRITE_BYTE(rbuf,byte)   \
+                       { (rbuf)->data[(rbuf)->pwrite]=(byte); \
+                       (rbuf)->pwrite=((rbuf)->pwrite+1)%(rbuf)->size; }
+/*
+** write <len> bytes to ring buffer
+** <usermem> specifies whether <buf> resides in user space
+** returns number of bytes transferred or -EFAULT
+*/
+extern ssize_t cmmb_ringbuffer_write(struct dvb_ringbuffer *rbuf, const u8 *buf,
+                                   size_t len);
+
+
+/**
+ * Write a packet into the ringbuffer.
+ *
+ * <rbuf> Ringbuffer to write to.
+ * <buf> Buffer to write.
+ * <len> Length of buffer (currently limited to 65535 bytes max).
+ * returns Number of bytes written, or -EFAULT, -ENOMEM, -EVINAL.
+ */
+
+
+#endif /* _DVB_RINGBUFFER_H_ */