164 lines
3.6 KiB
C
Executable File
164 lines
3.6 KiB
C
Executable File
/*
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*
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* dvb_ringbuffer.c: 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
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* & Marcus Metzler 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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* You should have received a copy of the GNU Lesser General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#include <linux/errno.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/sched.h>
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#include <linux/string.h>
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#include <asm/uaccess.h>
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#include "cmmb_ringbuffer.h"
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void cmmb_ringbuffer_init(struct dvb_ringbuffer *rbuf, void *data, size_t len)
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{
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rbuf->pread=rbuf->pwrite=0;
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rbuf->data=data;
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rbuf->size=len;
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rbuf->error=0;
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init_waitqueue_head(&rbuf->queue);
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spin_lock_init(&(rbuf->lock));
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}
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int cmmb_ringbuffer_empty(struct dvb_ringbuffer *rbuf)
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{
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return (rbuf->pread==rbuf->pwrite);
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}
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ssize_t cmmb_ringbuffer_free(struct dvb_ringbuffer *rbuf)
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{
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ssize_t free;
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free = rbuf->pread - rbuf->pwrite;
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if (free <= 0)
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free += rbuf->size;
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return free-1;
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}
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ssize_t cmmb_ringbuffer_avail(struct dvb_ringbuffer *rbuf)
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{
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ssize_t avail;
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avail = rbuf->pwrite - rbuf->pread;
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if (avail < 0)
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avail += rbuf->size;
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return avail;
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}
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void cmmb_ringbuffer_flush(struct dvb_ringbuffer *rbuf)
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{
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rbuf->pread = rbuf->pwrite;
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rbuf->error = 0;
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}
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void cmmb_ringbuffer_flush_spinlock_wakeup(struct dvb_ringbuffer *rbuf)
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{
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unsigned long flags;
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spin_lock_irqsave(&rbuf->lock, flags);
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cmmb_ringbuffer_flush(rbuf);
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spin_unlock_irqrestore(&rbuf->lock, flags);
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wake_up(&rbuf->queue);
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}
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ssize_t cmmb_ringbuffer_read(struct dvb_ringbuffer *rbuf, u8 *buf, size_t len, int usermem)
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{
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size_t todo = len;
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size_t split;
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split = (rbuf->pread + len > rbuf->size) ? rbuf->size - rbuf->pread : 0;
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if (split > 0) {
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if (!usermem)
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memcpy(buf, rbuf->data+rbuf->pread, split);
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else
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if (copy_to_user(buf, rbuf->data+rbuf->pread, split))
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return -EFAULT;
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buf += split;
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todo -= split;
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rbuf->pread = 0;
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}
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if (!usermem)
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memcpy(buf, rbuf->data+rbuf->pread, todo);
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else
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if (copy_to_user(buf, rbuf->data+rbuf->pread, todo))
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return -EFAULT;
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rbuf->pread = (rbuf->pread + todo) % rbuf->size;
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return len;
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}
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ssize_t cmmb_ringbuffer_write(struct dvb_ringbuffer *rbuf, const u8 *buf, size_t len)
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{
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size_t todo = len;
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size_t split;
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split = (rbuf->pwrite + len > rbuf->size) ? rbuf->size - rbuf->pwrite : 0;
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if (split > 0) {
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memcpy(rbuf->data+rbuf->pwrite, buf, split);
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buf += split;
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todo -= split;
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rbuf->pwrite = 0;
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}
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memcpy(rbuf->data+rbuf->pwrite, buf, todo);
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rbuf->pwrite = (rbuf->pwrite + todo) % rbuf->size;
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return len;
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}
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EXPORT_SYMBOL(cmmb_ringbuffer_init);
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EXPORT_SYMBOL(cmmb_ringbuffer_empty);
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EXPORT_SYMBOL(cmmb_ringbuffer_free);
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EXPORT_SYMBOL(cmmb_ringbuffer_avail);
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EXPORT_SYMBOL(cmmb_ringbuffer_flush_spinlock_wakeup);
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EXPORT_SYMBOL(cmmb_ringbuffer_read);
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EXPORT_SYMBOL(cmmb_ringbuffer_write);
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