1 files changed, 299 insertions, 0 deletions
diff --git a/drivers/media/dvb-core/dvb_ringbuffer.c b/drivers/media/dvb-core/dvb_ringbuffer.c
new file mode 100644
index 000000000000..a5712cd7c65f
--- /dev/null
+++ b/drivers/media/dvb-core/dvb_ringbuffer.c
@@ -0,0 +1,299 @@
+/*
+ *
+ * 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.
+ */
+
+
+
+#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;
+	rbuf->error=0;
+
+	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;
+	rbuf->error = 0;
+}
+EXPORT_SYMBOL(dvb_ringbuffer_flush);
+
+void dvb_ringbuffer_reset(struct dvb_ringbuffer *rbuf)
+{
+	rbuf->pread = rbuf->pwrite = 0;
+	rbuf->error = 0;
+}
+
+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_user(struct dvb_ringbuffer *rbuf, u8 __user *buf, size_t len)
+{
+	size_t todo = len;
+	size_t split;
+
+	split = (rbuf->pread + len > rbuf->size) ? rbuf->size - rbuf->pread : 0;
+	if (split > 0) {
+		if (copy_to_user(buf, rbuf->data+rbuf->pread, split))
+			return -EFAULT;
+		buf += split;
+		todo -= split;
+		rbuf->pread = 0;
+	}
+	if (copy_to_user(buf, rbuf->data+rbuf->pread, todo))
+		return -EFAULT;
+
+	rbuf->pread = (rbuf->pread + todo) % rbuf->size;
+
+	return len;
+}
+
+void dvb_ringbuffer_read(struct dvb_ringbuffer *rbuf, u8 *buf, size_t len)
+{
+	size_t todo = len;
+	size_t split;
+
+	split = (rbuf->pread + len > rbuf->size) ? rbuf->size - rbuf->pread : 0;
+	if (split > 0) {
+		memcpy(buf, rbuf->data+rbuf->pread, split);
+		buf += split;
+		todo -= split;
+		rbuf->pread = 0;
+	}
+	memcpy(buf, rbuf->data+rbuf->pread, todo);
+
+	rbuf->pread = (rbuf->pread + todo) % rbuf->size;
+}
+
+
+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_user(struct dvb_ringbuffer *rbuf, size_t idx,
+				int offset, u8 __user *buf, size_t len)
+{
+	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 (copy_to_user(buf, rbuf->data+idx, split))
+			return -EFAULT;
+		buf += split;
+		todo -= split;
+		idx = 0;
+	}
+	if (copy_to_user(buf, rbuf->data+idx, todo))
+		return -EFAULT;
+
+	return len;
+}
+
+ssize_t dvb_ringbuffer_pkt_read(struct dvb_ringbuffer *rbuf, size_t idx,
+				int offset, u8* buf, size_t len)
+{
+	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) {
+		memcpy(buf, rbuf->data+idx, split);
+		buf += split;
+		todo -= split;
+		idx = 0;
+	}
+	memcpy(buf, rbuf->data+idx, todo);
+	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_spinlock_wakeup);
+EXPORT_SYMBOL(dvb_ringbuffer_read_user);
+EXPORT_SYMBOL(dvb_ringbuffer_read);
+EXPORT_SYMBOL(dvb_ringbuffer_write);