3 * dvb_ringbuffer.c: ring buffer implementation for the dvb driver
5 * Copyright (C) 2003 Oliver Endriss
6 * Copyright (C) 2004 Andrew de Quincey
8 * based on code originally found in av7110.c & dvb_ci.c:
9 * Copyright (C) 1999-2003 Ralph Metzler
10 * & Marcus Metzler for convergence integrated media GmbH
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU Lesser General Public License
14 * as published by the Free Software Foundation; either version 2.1
15 * of the License, or (at your option) any later version.
17 * This program is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU Lesser General Public License for more details.
22 * You should have received a copy of the GNU Lesser General Public License
23 * along with this program; if not, write to the Free Software
24 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
29 #include <linux/errno.h>
30 #include <linux/kernel.h>
31 #include <linux/module.h>
32 #include <linux/sched.h>
33 #include <linux/string.h>
34 #include <asm/uaccess.h>
36 #include "cmmb_ringbuffer.h"
39 void cmmb_ringbuffer_init(struct dvb_ringbuffer *rbuf, void *data, size_t len)
41 rbuf->pread=rbuf->pwrite=0;
46 init_waitqueue_head(&rbuf->queue);
48 spin_lock_init(&(rbuf->lock));
54 int cmmb_ringbuffer_empty(struct dvb_ringbuffer *rbuf)
56 return (rbuf->pread==rbuf->pwrite);
61 ssize_t cmmb_ringbuffer_free(struct dvb_ringbuffer *rbuf)
65 free = rbuf->pread - rbuf->pwrite;
73 ssize_t cmmb_ringbuffer_avail(struct dvb_ringbuffer *rbuf)
77 avail = rbuf->pwrite - rbuf->pread;
85 void cmmb_ringbuffer_flush(struct dvb_ringbuffer *rbuf)
87 rbuf->pread = rbuf->pwrite;
93 void cmmb_ringbuffer_flush_spinlock_wakeup(struct dvb_ringbuffer *rbuf)
97 spin_lock_irqsave(&rbuf->lock, flags);
98 cmmb_ringbuffer_flush(rbuf);
99 spin_unlock_irqrestore(&rbuf->lock, flags);
101 wake_up(&rbuf->queue);
106 ssize_t cmmb_ringbuffer_read(struct dvb_ringbuffer *rbuf, u8 *buf, size_t len, int usermem)
111 split = (rbuf->pread + len > rbuf->size) ? rbuf->size - rbuf->pread : 0;
114 memcpy(buf, rbuf->data+rbuf->pread, split);
116 if (copy_to_user(buf, rbuf->data+rbuf->pread, split))
123 memcpy(buf, rbuf->data+rbuf->pread, todo);
125 if (copy_to_user(buf, rbuf->data+rbuf->pread, todo))
128 rbuf->pread = (rbuf->pread + todo) % rbuf->size;
135 ssize_t cmmb_ringbuffer_write(struct dvb_ringbuffer *rbuf, const u8 *buf, size_t len)
140 split = (rbuf->pwrite + len > rbuf->size) ? rbuf->size - rbuf->pwrite : 0;
143 memcpy(rbuf->data+rbuf->pwrite, buf, split);
148 memcpy(rbuf->data+rbuf->pwrite, buf, todo);
149 rbuf->pwrite = (rbuf->pwrite + todo) % rbuf->size;
157 EXPORT_SYMBOL(cmmb_ringbuffer_init);
158 EXPORT_SYMBOL(cmmb_ringbuffer_empty);
159 EXPORT_SYMBOL(cmmb_ringbuffer_free);
160 EXPORT_SYMBOL(cmmb_ringbuffer_avail);
161 EXPORT_SYMBOL(cmmb_ringbuffer_flush_spinlock_wakeup);
162 EXPORT_SYMBOL(cmmb_ringbuffer_read);
163 EXPORT_SYMBOL(cmmb_ringbuffer_write);