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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281/* * * 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, -EINVAL. */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_ */