/* * * 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);