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280 lines
8.3 KiB
280 lines
8.3 KiB
/* |
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* |
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* dvb_ringbuffer.h: ring buffer implementation for the dvb driver |
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* |
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* Copyright (C) 2003 Oliver Endriss |
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* Copyright (C) 2004 Andrew de Quincey |
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* |
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* based on code originally found in av7110.c & dvb_ci.c: |
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* Copyright (C) 1999-2003 Ralph Metzler & Marcus Metzler |
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* for convergence integrated media GmbH |
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* |
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* This program is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public License |
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* as published by the Free Software Foundation; either version 2.1 |
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* of the License, or (at your option) any later version. |
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* |
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* This program is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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* GNU Lesser General Public License for more details. |
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*/ |
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#ifndef _DVB_RINGBUFFER_H_ |
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#define _DVB_RINGBUFFER_H_ |
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#include <linux/spinlock.h> |
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#include <linux/wait.h> |
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/** |
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* struct dvb_ringbuffer - Describes a ring buffer used at DVB framework |
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* |
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* @data: Area were the ringbuffer data is written |
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* @size: size of the ringbuffer |
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* @pread: next position to read |
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* @pwrite: next position to write |
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* @error: used by ringbuffer clients to indicate that an error happened. |
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* @queue: Wait queue used by ringbuffer clients to indicate when buffer |
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* was filled |
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* @lock: Spinlock used to protect the ringbuffer |
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*/ |
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struct dvb_ringbuffer { |
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u8 *data; |
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ssize_t size; |
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ssize_t pread; |
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ssize_t pwrite; |
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int error; |
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wait_queue_head_t queue; |
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spinlock_t lock; |
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}; |
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#define DVB_RINGBUFFER_PKTHDRSIZE 3 |
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/** |
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* dvb_ringbuffer_init - initialize ring buffer, lock and queue |
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* |
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* @rbuf: pointer to struct dvb_ringbuffer |
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* @data: pointer to the buffer where the data will be stored |
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* @len: bytes from ring buffer into @buf |
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*/ |
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extern void dvb_ringbuffer_init(struct dvb_ringbuffer *rbuf, void *data, |
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size_t len); |
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/** |
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* dvb_ringbuffer_empty - test whether buffer is empty |
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* |
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* @rbuf: pointer to struct dvb_ringbuffer |
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*/ |
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extern int dvb_ringbuffer_empty(struct dvb_ringbuffer *rbuf); |
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/** |
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* dvb_ringbuffer_free - returns the number of free bytes in the buffer |
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* |
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* @rbuf: pointer to struct dvb_ringbuffer |
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* |
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* Return: number of free bytes in the buffer |
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*/ |
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extern ssize_t dvb_ringbuffer_free(struct dvb_ringbuffer *rbuf); |
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/** |
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* dvb_ringbuffer_avail - returns the number of bytes waiting in the buffer |
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* |
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* @rbuf: pointer to struct dvb_ringbuffer |
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* |
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* Return: number of bytes waiting in the buffer |
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*/ |
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extern ssize_t dvb_ringbuffer_avail(struct dvb_ringbuffer *rbuf); |
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/** |
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* dvb_ringbuffer_reset - resets the ringbuffer to initial state |
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* |
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* @rbuf: pointer to struct dvb_ringbuffer |
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* |
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* Resets the read and write pointers to zero and flush the buffer. |
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* |
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* This counts as a read and write operation |
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*/ |
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extern void dvb_ringbuffer_reset(struct dvb_ringbuffer *rbuf); |
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/* |
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* read routines & macros |
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*/ |
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/** |
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* dvb_ringbuffer_flush - flush buffer |
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* |
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* @rbuf: pointer to struct dvb_ringbuffer |
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*/ |
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extern void dvb_ringbuffer_flush(struct dvb_ringbuffer *rbuf); |
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/** |
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* dvb_ringbuffer_flush_spinlock_wakeup- flush buffer protected by spinlock |
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* and wake-up waiting task(s) |
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* |
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* @rbuf: pointer to struct dvb_ringbuffer |
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*/ |
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extern void dvb_ringbuffer_flush_spinlock_wakeup(struct dvb_ringbuffer *rbuf); |
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/** |
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* DVB_RINGBUFFER_PEEK - peek at byte @offs in the buffer |
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* |
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* @rbuf: pointer to struct dvb_ringbuffer |
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* @offs: offset inside the ringbuffer |
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*/ |
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#define DVB_RINGBUFFER_PEEK(rbuf, offs) \ |
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((rbuf)->data[((rbuf)->pread + (offs)) % (rbuf)->size]) |
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/** |
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* DVB_RINGBUFFER_SKIP - advance read ptr by @num bytes |
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* |
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* @rbuf: pointer to struct dvb_ringbuffer |
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* @num: number of bytes to advance |
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*/ |
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#define DVB_RINGBUFFER_SKIP(rbuf, num) {\ |
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(rbuf)->pread = ((rbuf)->pread + (num)) % (rbuf)->size;\ |
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} |
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/** |
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* dvb_ringbuffer_read_user - Reads a buffer into a user pointer |
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* |
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* @rbuf: pointer to struct dvb_ringbuffer |
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* @buf: pointer to the buffer where the data will be stored |
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* @len: bytes from ring buffer into @buf |
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* |
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* This variant assumes that the buffer is a memory at the userspace. So, |
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* it will internally call copy_to_user(). |
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* |
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* Return: number of bytes transferred or -EFAULT |
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*/ |
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extern ssize_t dvb_ringbuffer_read_user(struct dvb_ringbuffer *rbuf, |
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u8 __user *buf, size_t len); |
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/** |
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* dvb_ringbuffer_read - Reads a buffer into a pointer |
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* |
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* @rbuf: pointer to struct dvb_ringbuffer |
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* @buf: pointer to the buffer where the data will be stored |
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* @len: bytes from ring buffer into @buf |
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* |
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* This variant assumes that the buffer is a memory at the Kernel space |
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* |
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* Return: number of bytes transferred or -EFAULT |
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*/ |
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extern void dvb_ringbuffer_read(struct dvb_ringbuffer *rbuf, |
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u8 *buf, size_t len); |
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/* |
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* write routines & macros |
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*/ |
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/** |
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* DVB_RINGBUFFER_WRITE_BYTE - write single byte to ring buffer |
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* |
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* @rbuf: pointer to struct dvb_ringbuffer |
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* @byte: byte to write |
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*/ |
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#define DVB_RINGBUFFER_WRITE_BYTE(rbuf, byte) \ |
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{ (rbuf)->data[(rbuf)->pwrite] = (byte); \ |
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(rbuf)->pwrite = ((rbuf)->pwrite + 1) % (rbuf)->size; } |
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/** |
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* dvb_ringbuffer_write - Writes a buffer into the ringbuffer |
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* |
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* @rbuf: pointer to struct dvb_ringbuffer |
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* @buf: pointer to the buffer where the data will be read |
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* @len: bytes from ring buffer into @buf |
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* |
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* This variant assumes that the buffer is a memory at the Kernel space |
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* |
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* return: number of bytes transferred or -EFAULT |
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*/ |
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extern ssize_t dvb_ringbuffer_write(struct dvb_ringbuffer *rbuf, const u8 *buf, |
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size_t len); |
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/** |
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* dvb_ringbuffer_write_user - Writes a buffer received via a user pointer |
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* |
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* @rbuf: pointer to struct dvb_ringbuffer |
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* @buf: pointer to the buffer where the data will be read |
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* @len: bytes from ring buffer into @buf |
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* |
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* This variant assumes that the buffer is a memory at the userspace. So, |
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* it will internally call copy_from_user(). |
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* |
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* Return: number of bytes transferred or -EFAULT |
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*/ |
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extern ssize_t dvb_ringbuffer_write_user(struct dvb_ringbuffer *rbuf, |
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const u8 __user *buf, size_t len); |
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/** |
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* dvb_ringbuffer_pkt_write - Write a packet into the ringbuffer. |
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* |
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* @rbuf: Ringbuffer to write to. |
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* @buf: Buffer to write. |
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* @len: Length of buffer (currently limited to 65535 bytes max). |
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* |
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* Return: Number of bytes written, or -EFAULT, -ENOMEM, -EVINAL. |
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*/ |
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extern ssize_t dvb_ringbuffer_pkt_write(struct dvb_ringbuffer *rbuf, u8 *buf, |
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size_t len); |
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/** |
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* dvb_ringbuffer_pkt_read_user - Read from a packet in the ringbuffer. |
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* |
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* @rbuf: Ringbuffer concerned. |
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* @idx: Packet index as returned by dvb_ringbuffer_pkt_next(). |
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* @offset: Offset into packet to read from. |
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* @buf: Destination buffer for data. |
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* @len: Size of destination buffer. |
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* |
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* Return: Number of bytes read, or -EFAULT. |
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* |
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* .. note:: |
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* |
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* unlike dvb_ringbuffer_read(), this does **NOT** update the read pointer |
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* in the ringbuffer. You must use dvb_ringbuffer_pkt_dispose() to mark a |
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* packet as no longer required. |
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*/ |
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extern ssize_t dvb_ringbuffer_pkt_read_user(struct dvb_ringbuffer *rbuf, |
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size_t idx, |
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int offset, u8 __user *buf, |
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size_t len); |
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/** |
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* dvb_ringbuffer_pkt_read - Read from a packet in the ringbuffer. |
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* Note: unlike dvb_ringbuffer_read_user(), this DOES update the read pointer |
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* in the ringbuffer. |
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* |
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* @rbuf: Ringbuffer concerned. |
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* @idx: Packet index as returned by dvb_ringbuffer_pkt_next(). |
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* @offset: Offset into packet to read from. |
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* @buf: Destination buffer for data. |
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* @len: Size of destination buffer. |
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* |
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* Return: Number of bytes read, or -EFAULT. |
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*/ |
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extern ssize_t dvb_ringbuffer_pkt_read(struct dvb_ringbuffer *rbuf, size_t idx, |
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int offset, u8 *buf, size_t len); |
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/** |
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* dvb_ringbuffer_pkt_dispose - Dispose of a packet in the ring buffer. |
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* |
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* @rbuf: Ring buffer concerned. |
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* @idx: Packet index as returned by dvb_ringbuffer_pkt_next(). |
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*/ |
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extern void dvb_ringbuffer_pkt_dispose(struct dvb_ringbuffer *rbuf, size_t idx); |
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/** |
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* dvb_ringbuffer_pkt_next - Get the index of the next packet in a ringbuffer. |
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* |
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* @rbuf: Ringbuffer concerned. |
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* @idx: Previous packet index, or -1 to return the first packet index. |
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* @pktlen: On success, will be updated to contain the length of the packet |
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* in bytes. |
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* returns Packet index (if >=0), or -1 if no packets available. |
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*/ |
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extern ssize_t dvb_ringbuffer_pkt_next(struct dvb_ringbuffer *rbuf, |
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size_t idx, size_t *pktlen); |
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#endif /* _DVB_RINGBUFFER_H_ */
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