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path: root/drivers/media/dvb/dvb-core/dvb_ringbuffer.c
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Diffstat (limited to 'drivers/media/dvb/dvb-core/dvb_ringbuffer.c')
-rw-r--r--drivers/media/dvb/dvb-core/dvb_ringbuffer.c270
1 files changed, 270 insertions, 0 deletions
diff --git a/drivers/media/dvb/dvb-core/dvb_ringbuffer.c b/drivers/media/dvb/dvb-core/dvb_ringbuffer.c
new file mode 100644
index 000000000000..fb6d94a69d71
--- /dev/null
+++ b/drivers/media/dvb/dvb-core/dvb_ringbuffer.c
@@ -0,0 +1,270 @@
+/*
+ *
+ * dvb_ringbuffer.c: 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.
+ */
+
+
+
+#define __KERNEL_SYSCALLS__
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/string.h>
+#include <asm/uaccess.h>
+
+#include "dvb_ringbuffer.h"
+
+#define PKT_READY 0
+#define PKT_DISPOSED 1
+
+
+void dvb_ringbuffer_init(struct dvb_ringbuffer *rbuf, void *data, size_t len)
+{
+ rbuf->pread=rbuf->pwrite=0;
+ rbuf->data=data;
+ rbuf->size=len;
+
+ init_waitqueue_head(&rbuf->queue);
+
+ spin_lock_init(&(rbuf->lock));
+}
+
+
+
+int dvb_ringbuffer_empty(struct dvb_ringbuffer *rbuf)
+{
+ return (rbuf->pread==rbuf->pwrite);
+}
+
+
+
+ssize_t dvb_ringbuffer_free(struct dvb_ringbuffer *rbuf)
+{
+ ssize_t free;
+
+ free = rbuf->pread - rbuf->pwrite;
+ if (free <= 0)
+ free += rbuf->size;
+ return free-1;
+}
+
+
+
+ssize_t dvb_ringbuffer_avail(struct dvb_ringbuffer *rbuf)
+{
+ ssize_t avail;
+
+ avail = rbuf->pwrite - rbuf->pread;
+ if (avail < 0)
+ avail += rbuf->size;
+ return avail;
+}
+
+
+
+void dvb_ringbuffer_flush(struct dvb_ringbuffer *rbuf)
+{
+ rbuf->pread = rbuf->pwrite;
+}
+
+
+
+void dvb_ringbuffer_flush_spinlock_wakeup(struct dvb_ringbuffer *rbuf)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&rbuf->lock, flags);
+ dvb_ringbuffer_flush(rbuf);
+ spin_unlock_irqrestore(&rbuf->lock, flags);
+
+ wake_up(&rbuf->queue);
+}
+
+
+
+ssize_t dvb_ringbuffer_read(struct dvb_ringbuffer *rbuf, u8 *buf, size_t len, int usermem)
+{
+ size_t todo = len;
+ size_t split;
+
+ split = (rbuf->pread + len > rbuf->size) ? rbuf->size - rbuf->pread : 0;
+ if (split > 0) {
+ if (!usermem)
+ memcpy(buf, rbuf->data+rbuf->pread, split);
+ else
+ if (copy_to_user(buf, rbuf->data+rbuf->pread, split))
+ return -EFAULT;
+ buf += split;
+ todo -= split;
+ rbuf->pread = 0;
+ }
+ if (!usermem)
+ memcpy(buf, rbuf->data+rbuf->pread, todo);
+ else
+ if (copy_to_user(buf, rbuf->data+rbuf->pread, todo))
+ return -EFAULT;
+
+ rbuf->pread = (rbuf->pread + todo) % rbuf->size;
+
+ return len;
+}
+
+
+
+ssize_t dvb_ringbuffer_write(struct dvb_ringbuffer *rbuf, const u8 *buf, size_t len)
+{
+ size_t todo = len;
+ size_t split;
+
+ split = (rbuf->pwrite + len > rbuf->size) ? rbuf->size - rbuf->pwrite : 0;
+
+ if (split > 0) {
+ memcpy(rbuf->data+rbuf->pwrite, buf, split);
+ buf += split;
+ todo -= split;
+ rbuf->pwrite = 0;
+ }
+ memcpy(rbuf->data+rbuf->pwrite, buf, todo);
+ rbuf->pwrite = (rbuf->pwrite + todo) % rbuf->size;
+
+ return len;
+}
+
+ssize_t dvb_ringbuffer_pkt_write(struct dvb_ringbuffer *rbuf, u8* buf, size_t len)
+{
+ int status;
+ ssize_t oldpwrite = rbuf->pwrite;
+
+ DVB_RINGBUFFER_WRITE_BYTE(rbuf, len >> 8);
+ DVB_RINGBUFFER_WRITE_BYTE(rbuf, len & 0xff);
+ DVB_RINGBUFFER_WRITE_BYTE(rbuf, PKT_READY);
+ status = dvb_ringbuffer_write(rbuf, buf, len);
+
+ if (status < 0) rbuf->pwrite = oldpwrite;
+ return status;
+}
+
+ssize_t dvb_ringbuffer_pkt_read(struct dvb_ringbuffer *rbuf, size_t idx,
+ int offset, u8* buf, size_t len, int usermem)
+{
+ size_t todo;
+ size_t split;
+ size_t pktlen;
+
+ pktlen = rbuf->data[idx] << 8;
+ pktlen |= rbuf->data[(idx + 1) % rbuf->size];
+ if (offset > pktlen) return -EINVAL;
+ if ((offset + len) > pktlen) len = pktlen - offset;
+
+ idx = (idx + DVB_RINGBUFFER_PKTHDRSIZE + offset) % rbuf->size;
+ todo = len;
+ split = ((idx + len) > rbuf->size) ? rbuf->size - idx : 0;
+ if (split > 0) {
+ if (!usermem)
+ memcpy(buf, rbuf->data+idx, split);
+ else
+ if (copy_to_user(buf, rbuf->data+idx, split))
+ return -EFAULT;
+ buf += split;
+ todo -= split;
+ idx = 0;
+ }
+ if (!usermem)
+ memcpy(buf, rbuf->data+idx, todo);
+ else
+ if (copy_to_user(buf, rbuf->data+idx, todo))
+ return -EFAULT;
+
+ return len;
+}
+
+void dvb_ringbuffer_pkt_dispose(struct dvb_ringbuffer *rbuf, size_t idx)
+{
+ size_t pktlen;
+
+ rbuf->data[(idx + 2) % rbuf->size] = PKT_DISPOSED;
+
+ // clean up disposed packets
+ while(dvb_ringbuffer_avail(rbuf) > DVB_RINGBUFFER_PKTHDRSIZE) {
+ if (DVB_RINGBUFFER_PEEK(rbuf, 2) == PKT_DISPOSED) {
+ pktlen = DVB_RINGBUFFER_PEEK(rbuf, 0) << 8;
+ pktlen |= DVB_RINGBUFFER_PEEK(rbuf, 1);
+ DVB_RINGBUFFER_SKIP(rbuf, pktlen + DVB_RINGBUFFER_PKTHDRSIZE);
+ } else {
+ // first packet is not disposed, so we stop cleaning now
+ break;
+ }
+ }
+}
+
+ssize_t dvb_ringbuffer_pkt_next(struct dvb_ringbuffer *rbuf, size_t idx, size_t* pktlen)
+{
+ int consumed;
+ int curpktlen;
+ int curpktstatus;
+
+ if (idx == -1) {
+ idx = rbuf->pread;
+ } else {
+ curpktlen = rbuf->data[idx] << 8;
+ curpktlen |= rbuf->data[(idx + 1) % rbuf->size];
+ idx = (idx + curpktlen + DVB_RINGBUFFER_PKTHDRSIZE) % rbuf->size;
+ }
+
+ consumed = (idx - rbuf->pread) % rbuf->size;
+
+ while((dvb_ringbuffer_avail(rbuf) - consumed) > DVB_RINGBUFFER_PKTHDRSIZE) {
+
+ curpktlen = rbuf->data[idx] << 8;
+ curpktlen |= rbuf->data[(idx + 1) % rbuf->size];
+ curpktstatus = rbuf->data[(idx + 2) % rbuf->size];
+
+ if (curpktstatus == PKT_READY) {
+ *pktlen = curpktlen;
+ return idx;
+ }
+
+ consumed += curpktlen + DVB_RINGBUFFER_PKTHDRSIZE;
+ idx = (idx + curpktlen + DVB_RINGBUFFER_PKTHDRSIZE) % rbuf->size;
+ }
+
+ // no packets available
+ return -1;
+}
+
+
+
+EXPORT_SYMBOL(dvb_ringbuffer_init);
+EXPORT_SYMBOL(dvb_ringbuffer_empty);
+EXPORT_SYMBOL(dvb_ringbuffer_free);
+EXPORT_SYMBOL(dvb_ringbuffer_avail);
+EXPORT_SYMBOL(dvb_ringbuffer_flush);
+EXPORT_SYMBOL(dvb_ringbuffer_flush_spinlock_wakeup);
+EXPORT_SYMBOL(dvb_ringbuffer_read);
+EXPORT_SYMBOL(dvb_ringbuffer_write);
+EXPORT_SYMBOL(dvb_ringbuffer_pkt_write);
+EXPORT_SYMBOL(dvb_ringbuffer_pkt_read);
+EXPORT_SYMBOL(dvb_ringbuffer_pkt_dispose);
+EXPORT_SYMBOL(dvb_ringbuffer_pkt_next);