/* * * 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. * * 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_ #define _DVB_RINGBUFFER_H_ #include #include 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 /* * 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 */ extern int dvb_ringbuffer_empty(struct dvb_ringbuffer *rbuf); /* return the 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 */ extern ssize_t dvb_ringbuffer_avail(struct dvb_ringbuffer *rbuf); /* * Reset 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 */ extern void dvb_ringbuffer_flush(struct dvb_ringbuffer *rbuf); /* flush buffer protected by spinlock and wake-up waiting task(s) */ 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] /* advance read ptr by @num: bytes */ #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 */ extern ssize_t dvb_ringbuffer_read_user(struct dvb_ringbuffer *rbuf, u8 __user *buf, size_t len); 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 */ 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_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. */ 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. * 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. * * @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. * * returns Number of bytes read, or -EFAULT. */ 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. * * returns 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_ */