* 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_
#include <linux/spinlock.h>
#include <linux/wait.h>
+/**
+ * struct dvb_ringbuffer - Describes a ring buffer used at DVB framework
+ *
+ * @data: Area were the ringbuffer data is written
+ * @size: size of the ringbuffer
+ * @pread: next position to read
+ * @pwrite: next position to write
+ * @error: used by ringbuffer clients to indicate that an error happened.
+ * @queue: Wait queue used by ringbuffer clients to indicate when buffer
+ * was filled
+ * @lock: Spinlock used to protect the ringbuffer
+ */
struct dvb_ringbuffer {
u8 *data;
ssize_t size;
#define DVB_RINGBUFFER_PKTHDRSIZE 3
+/**
+ * dvb_ringbuffer_init - initialize ring buffer, lock and queue
+ *
+ * @rbuf: pointer to struct dvb_ringbuffer
+ * @data: pointer to the buffer where the data will be stored
+ * @len: bytes from ring buffer into @buf
+ */
+extern void dvb_ringbuffer_init(struct dvb_ringbuffer *rbuf, void *data,
+ size_t len);
-/*
- * 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));
- * 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.
- * Resetting the buffer counts as a read and write operation.
- * Two or more writers must be locked against each other.
- */
-
-/* initialize ring buffer, lock and queue */
-extern void dvb_ringbuffer_init(struct dvb_ringbuffer *rbuf, void *data, size_t len);
-
-/* test whether buffer is empty */
+/**
+ * dvb_ringbuffer_empty - test whether buffer is empty
+ *
+ * @rbuf: pointer to struct dvb_ringbuffer
+ */
extern int dvb_ringbuffer_empty(struct dvb_ringbuffer *rbuf);
-/* return the number of free bytes in the buffer */
+/**
+ * dvb_ringbuffer_free - returns the number of free bytes in the buffer
+ *
+ * @rbuf: pointer to struct dvb_ringbuffer
+ *
+ * Return: number of free bytes in the buffer
+ */
extern ssize_t dvb_ringbuffer_free(struct dvb_ringbuffer *rbuf);
-/* return the number of bytes waiting in the buffer */
+/**
+ * dvb_ringbuffer_avail - returns the number of bytes waiting in the buffer
+ *
+ * @rbuf: pointer to struct dvb_ringbuffer
+ *
+ * Return: number of bytes waiting in the buffer
+ */
extern ssize_t dvb_ringbuffer_avail(struct dvb_ringbuffer *rbuf);
-
-/*
- * Reset the read and write pointers to zero and flush the buffer
+/**
+ * dvb_ringbuffer_reset - resets the ringbuffer to initial state
+ *
+ * @rbuf: pointer to struct dvb_ringbuffer
+ *
+ * Resets the read and write pointers to zero and flush the buffer.
+ *
* This counts as a read and write operation
*/
extern void dvb_ringbuffer_reset(struct dvb_ringbuffer *rbuf);
+/*
+ * read routines & macros
+ */
-/* read routines & macros */
-/* ---------------------- */
-/* flush buffer */
+/**
+ * dvb_ringbuffer_flush - flush buffer
+ *
+ * @rbuf: pointer to struct dvb_ringbuffer
+ */
extern void dvb_ringbuffer_flush(struct dvb_ringbuffer *rbuf);
-/* flush buffer protected by spinlock and wake-up waiting task(s) */
+/**
+ * dvb_ringbuffer_flush_spinlock_wakeup- flush buffer protected by spinlock
+ * and wake-up waiting task(s)
+ *
+ * @rbuf: pointer to struct dvb_ringbuffer
+ */
extern void dvb_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]
+/**
+ * DVB_RINGBUFFER_PEEK - peek at byte @offs in the buffer
+ *
+ * @rbuf: pointer to struct dvb_ringbuffer
+ * @offs: offset inside the ringbuffer
+ */
+#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
+/**
+ * DVB_RINGBUFFER_SKIP - advance read ptr by @num bytes
+ *
+ * @rbuf: pointer to struct dvb_ringbuffer
+ * @num: number of bytes to advance
+ */
+#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
+/**
+ * dvb_ringbuffer_read_user - Reads a buffer into an user pointer
+ *
+ * @rbuf: pointer to struct dvb_ringbuffer
+ * @buf: pointer to the buffer where the data will be stored
+ * @len: bytes from ring buffer into @buf
+ *
+ * This variant assumes that the buffer is a memory at the userspace. So,
+ * it will internally call copy_to_user().
+ *
+ * Return: number of bytes transferred or -EFAULT
*/
extern ssize_t dvb_ringbuffer_read_user(struct dvb_ringbuffer *rbuf,
u8 __user *buf, size_t len);
+
+/**
+ * dvb_ringbuffer_read - Reads a buffer into a pointer
+ *
+ * @rbuf: pointer to struct dvb_ringbuffer
+ * @buf: pointer to the buffer where the data will be stored
+ * @len: bytes from ring buffer into @buf
+ *
+ * This variant assumes that the buffer is a memory at the Kernel space
+ *
+ * Return: number of bytes transferred or -EFAULT
+ */
extern void dvb_ringbuffer_read(struct dvb_ringbuffer *rbuf,
u8 *buf, size_t len);
-
-/* 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
-*/
+ * write routines & macros
+ */
+
+/**
+ * DVB_RINGBUFFER_WRITE_BYTE - write single byte to ring buffer
+ *
+ * @rbuf: pointer to struct dvb_ringbuffer
+ * @byte: byte to write
+ */
+#define DVB_RINGBUFFER_WRITE_BYTE(rbuf, byte) \
+ { (rbuf)->data[(rbuf)->pwrite] = (byte); \
+ (rbuf)->pwrite = ((rbuf)->pwrite + 1) % (rbuf)->size; }
+
+/**
+ * dvb_ringbuffer_write - Writes a buffer into the ringbuffer
+ *
+ * @rbuf: pointer to struct dvb_ringbuffer
+ * @buf: pointer to the buffer where the data will be read
+ * @len: bytes from ring buffer into @buf
+ *
+ * This variant assumes that the buffer is a memory at the Kernel space
+ *
+ * return: number of bytes transferred or -EFAULT
+ */
extern ssize_t dvb_ringbuffer_write(struct dvb_ringbuffer *rbuf, const u8 *buf,
size_t len);
-extern ssize_t dvb_ringbuffer_write_user(struct dvb_ringbuffer *rbuf,
- const u8 __user *buf, size_t len);
+/**
+ * dvb_ringbuffer_write_user - Writes a buffer received via an user pointer
+ *
+ * @rbuf: pointer to struct dvb_ringbuffer
+ * @buf: pointer to the buffer where the data will be read
+ * @len: bytes from ring buffer into @buf
+ *
+ * This variant assumes that the buffer is a memory at the userspace. So,
+ * it will internally call copy_from_user().
+ *
+ * Return: number of bytes transferred or -EFAULT
+ */
+extern ssize_t dvb_ringbuffer_write_user(struct dvb_ringbuffer *rbuf,
+ const u8 __user *buf, size_t len);
/**
* dvb_ringbuffer_pkt_write - 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.
+ *
+ * Return: Number of bytes written, or -EFAULT, -ENOMEM, -EVINAL.
*/
-extern ssize_t dvb_ringbuffer_pkt_write(struct dvb_ringbuffer *rbuf, u8* buf,
+extern ssize_t dvb_ringbuffer_pkt_write(struct dvb_ringbuffer *rbuf, u8 *buf,
size_t len);
/**
* @buf: Destination buffer for data.
* @len: Size of destination buffer.
*
- * returns Number of bytes read, or -EFAULT.
+ * Return: Number of bytes read, or -EFAULT.
*
* .. note::
*
*/
extern ssize_t dvb_ringbuffer_pkt_read_user(struct dvb_ringbuffer *rbuf,
size_t idx,
- int offset, u8 __user *buf,
+ int offset, u8 __user *buf,
size_t len);
/**
* @buf: Destination buffer for data.
* @len: Size of destination buffer.
*
- * returns Number of bytes read, or -EFAULT.
+ * Return: Number of bytes read, or -EFAULT.
*/
extern ssize_t dvb_ringbuffer_pkt_read(struct dvb_ringbuffer *rbuf, size_t idx,
int offset, u8 *buf, size_t len);
*
* @rbuf: Ringbuffer concerned.
* @idx: Previous packet index, or -1 to return the first packet index.
- * @pktlen: On success, will be updated to contain the length of the packet in bytes.
+ * @pktlen: On success, will be updated to contain the length of the packet
+ * in bytes.
* returns Packet index (if >=0), or -1 if no packets available.
*/
-extern ssize_t dvb_ringbuffer_pkt_next(struct dvb_ringbuffer *rbuf, size_t idx, size_t* pktlen);
-
+extern ssize_t dvb_ringbuffer_pkt_next(struct dvb_ringbuffer *rbuf,
+ size_t idx, size_t *pktlen);
#endif /* _DVB_RINGBUFFER_H_ */
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