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[media] dvb_ringbuffer.h: Document all functions

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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>
This commit is contained in:
Mauro Carvalho Chehab 2016-08-29 08:38:01 -03:00
parent b3ef4445fc
commit ff54c19d8e
1 changed files with 134 additions and 45 deletions
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179
drivers/media/dvb-core/dvb_ringbuffer.h
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@ -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 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
*/
/* 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; }
/**
* 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_ */