[PATCH 05/47] [media] dvb_ringbuffer.h: Document all functions

Mauro Carvalho Chehab
2016-09-08T12:04:18Z

There are several functions there there weren't properly
documented. Add documentation for them.

While here, make checkpatch.pl happier.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
---
drivers/media/dvb-core/dvb_ringbuffer.h | 179 ++++++++++++++++++++++++--------
1 file changed, 134 insertions(+), 45 deletions(-)

diff --git a/drivers/media/dvb-core/dvb_ringbuffer.h b/drivers/media/dvb-core/dvb_ringbuffer.h
index 8af642399f1e..8209eb4db2aa 100644
--- a/drivers/media/dvb-core/dvb_ringbuffer.h
+++ b/drivers/media/dvb-core/dvb_ringbuffer.h
@@ -18,10 +18,6 @@
* 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_
@@ -30,6 +26,18 @@
#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;
@@ -43,7 +51,21 @@ struct dvb_ringbuffer {

#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);

+/**
+ * dvb_ringbuffer_empty - test whether buffer is empty
+ *
+ * @rbuf: pointer to struct dvb_ringbuffer
+ */
/*
* Notes:
* ------
@@ -72,69 +94,133 @@ struct dvb_ringbuffer {
* 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 */
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 */
-/* ---------------------- */
-/* flush buffer */
+/*
+ * read routines & macros
+ */
+
+/**
+ * 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 */
+#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
+#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 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
-*/
+#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);
+
+/**
+ * dvb_ringbuffer_writeuser - 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);
+ const u8 __user *buf, size_t len);

/**
@@ -143,9 +229,10 @@ extern ssize_t dvb_ringbuffer_write_user(struct dvb_ringbuffer *rbuf,
* @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);

/**
@@ -157,7 +244,7 @@ extern ssize_t dvb_ringbuffer_pkt_write(struct dvb_ringbuffer *rbuf, u8* buf,
* @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::
*
@@ -167,7 +254,7 @@ extern ssize_t dvb_ringbuffer_pkt_write(struct dvb_ringbuffer *rbuf, u8* buf,
*/
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);

/**
@@ -181,7 +268,7 @@ extern ssize_t dvb_ringbuffer_pkt_read_user(struct dvb_ringbuffer *rbuf,
* @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);
@@ -199,10 +286,12 @@ extern void dvb_ringbuffer_pkt_dispose(struct dvb_ringbuffer *rbuf, size_t idx);
*
* @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_ */
--
2.7.4