mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-26 10:49:33 +00:00
![Mauro Carvalho Chehab](/assets/img/avatar_default.png)
Except for DVB, all media kAPI headers are at include/media. Move the headers to it. Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
280 lines
8.3 KiB
C
280 lines
8.3 KiB
C
/*
|
|
*
|
|
* 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.
|
|
*/
|
|
|
|
#ifndef _DVB_RINGBUFFER_H_
|
|
#define _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;
|
|
ssize_t pread;
|
|
ssize_t pwrite;
|
|
int error;
|
|
|
|
wait_queue_head_t queue;
|
|
spinlock_t lock;
|
|
};
|
|
|
|
#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
|
|
*/
|
|
extern int dvb_ringbuffer_empty(struct dvb_ringbuffer *rbuf);
|
|
|
|
/**
|
|
* 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);
|
|
|
|
/**
|
|
* 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);
|
|
|
|
/**
|
|
* 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
|
|
*/
|
|
|
|
/**
|
|
* dvb_ringbuffer_flush - flush buffer
|
|
*
|
|
* @rbuf: pointer to struct dvb_ringbuffer
|
|
*/
|
|
extern void dvb_ringbuffer_flush(struct dvb_ringbuffer *rbuf);
|
|
|
|
/**
|
|
* 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);
|
|
|
|
/**
|
|
* 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])
|
|
|
|
/**
|
|
* 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;\
|
|
}
|
|
|
|
/**
|
|
* dvb_ringbuffer_read_user - Reads a buffer into a 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
|
|
*/
|
|
|
|
/**
|
|
* 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);
|
|
|
|
/**
|
|
* dvb_ringbuffer_write_user - Writes a buffer received via a 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).
|
|
*
|
|
* Return: Number of bytes written, or -EFAULT, -ENOMEM, -EVINAL.
|
|
*/
|
|
extern ssize_t dvb_ringbuffer_pkt_write(struct dvb_ringbuffer *rbuf, u8 *buf,
|
|
size_t len);
|
|
|
|
/**
|
|
* dvb_ringbuffer_pkt_read_user - Read from a packet in the ringbuffer.
|
|
*
|
|
* @rbuf: Ringbuffer concerned.
|
|
* @idx: Packet index as returned by dvb_ringbuffer_pkt_next().
|
|
* @offset: Offset into packet to read from.
|
|
* @buf: Destination buffer for data.
|
|
* @len: Size of destination buffer.
|
|
*
|
|
* Return: Number of bytes read, or -EFAULT.
|
|
*
|
|
* .. note::
|
|
*
|
|
* unlike dvb_ringbuffer_read(), this does **NOT** update the read pointer
|
|
* in the ringbuffer. You must use dvb_ringbuffer_pkt_dispose() to mark a
|
|
* packet as no longer required.
|
|
*/
|
|
extern ssize_t dvb_ringbuffer_pkt_read_user(struct dvb_ringbuffer *rbuf,
|
|
size_t idx,
|
|
int offset, u8 __user *buf,
|
|
size_t len);
|
|
|
|
/**
|
|
* dvb_ringbuffer_pkt_read - Read from a packet in the ringbuffer.
|
|
* Note: unlike dvb_ringbuffer_read_user(), this DOES update the read pointer
|
|
* in the ringbuffer.
|
|
*
|
|
* @rbuf: Ringbuffer concerned.
|
|
* @idx: Packet index as returned by dvb_ringbuffer_pkt_next().
|
|
* @offset: Offset into packet to read from.
|
|
* @buf: Destination buffer for data.
|
|
* @len: Size of destination buffer.
|
|
*
|
|
* 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);
|
|
|
|
/**
|
|
* dvb_ringbuffer_pkt_dispose - Dispose of a packet in the ring buffer.
|
|
*
|
|
* @rbuf: Ring buffer concerned.
|
|
* @idx: Packet index as returned by dvb_ringbuffer_pkt_next().
|
|
*/
|
|
extern void dvb_ringbuffer_pkt_dispose(struct dvb_ringbuffer *rbuf, size_t idx);
|
|
|
|
/**
|
|
* dvb_ringbuffer_pkt_next - Get the index of the next packet in a ringbuffer.
|
|
*
|
|
* @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.
|
|
* 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);
|
|
|
|
#endif /* _DVB_RINGBUFFER_H_ */
|