diff options
Diffstat (limited to 'drivers/media/dvb/dvb-core/dvb_ringbuffer.c')
| -rw-r--r-- | drivers/media/dvb/dvb-core/dvb_ringbuffer.c | 270 |
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); |