/*
 * dvb_demux.c - DVB kernel demux API
 *
 * Copyright (C) 2000-2001 Ralph  Metzler <ralph@convergence.de>
 *                     & Marcus Metzler <marcus@convergence.de>
 *                       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 General Public License for more details.
 *
 */

#define pr_fmt(fmt) "dvb_demux: " fmt

#include <linux/sched/signal.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/module.h>
#include <linux/poll.h>
#include <linux/string.h>
#include <linux/crc32.h>
#include <linux/uaccess.h>
#include <asm/div64.h>

#include <media/dvb_demux.h>

static int dvb_demux_tscheck;
module_param(dvb_demux_tscheck, int, 0644);
MODULE_PARM_DESC(dvb_demux_tscheck,
                "enable transport stream continuity and TEI check");

static int dvb_demux_speedcheck;
module_param(dvb_demux_speedcheck, int, 0644);
MODULE_PARM_DESC(dvb_demux_speedcheck,
                "enable transport stream speed check");

static int dvb_demux_feed_err_pkts = 1;
module_param(dvb_demux_feed_err_pkts, int, 0644);
MODULE_PARM_DESC(dvb_demux_feed_err_pkts,
                 "when set to 0, drop packets with the TEI bit set (1 by default)");

#define dprintk(fmt, arg...) \
        printk(KERN_DEBUG pr_fmt("%s: " fmt),  __func__, ##arg)

#define dprintk_tscheck(x...) do {                      \
        if (dvb_demux_tscheck && printk_ratelimit())    \
                dprintk(x);                             \
} while (0)

#ifdef CONFIG_DVB_DEMUX_SECTION_LOSS_LOG
#  define dprintk_sect_loss(x...) dprintk(x)
#else
#  define dprintk_sect_loss(x...)
#endif

#define set_buf_flags(__feed, __flag)                   \
        do {                                            \
                (__feed)->buffer_flags |= (__flag);     \
        } while (0)

/******************************************************************************
 * static inlined helper functions
 ******************************************************************************/

static inline u16 section_length(const u8 *buf)
{
        return 3 + ((buf[1] & 0x0f) << 8) + buf[2];
}

static inline u16 ts_pid(const u8 *buf)
{
        return ((buf[1] & 0x1f) << 8) + buf[2];
}

static inline u8 payload(const u8 *tsp)
{
        if (!(tsp[3] & 0x10))   // no payload?
                return 0;

        if (tsp[3] & 0x20) {    // adaptation field?
                if (tsp[4] > 183)       // corrupted data?
                        return 0;
                else
                        return 184 - 1 - tsp[4];
        }

        return 184;
}

static u32 dvb_dmx_crc32(struct dvb_demux_feed *f, const u8 *src, size_t len)
{
        return (f->feed.sec.crc_val = crc32_be(f->feed.sec.crc_val, src, len));
}

static void dvb_dmx_memcopy(struct dvb_demux_feed *f, u8 *d, const u8 *s,
                            size_t len)
{
        memcpy(d, s, len);
}

/******************************************************************************
 * Software filter functions
 ******************************************************************************/

static inline int dvb_dmx_swfilter_payload(struct dvb_demux_feed *feed,
                                           const u8 *buf)
{
        int count = payload(buf);
        int p;
        int ccok;
        u8 cc;

        if (count == 0)
                return -1;

        p = 188 - count;

        cc = buf[3] & 0x0f;
        ccok = ((feed->cc + 1) & 0x0f) == cc;
        feed->cc = cc;
        if (!ccok) {
                set_buf_flags(feed, DMX_BUFFER_FLAG_DISCONTINUITY_DETECTED);
                dprintk_sect_loss("missed packet: %d instead of %d!\n",
                                  cc, (feed->cc + 1) & 0x0f);
        }

        if (buf[1] & 0x40)      // PUSI ?
                feed->peslen = 0xfffa;

        feed->peslen += count;

        return feed->cb.ts(&buf[p], count, NULL, 0, &feed->feed.ts,
                           &feed->buffer_flags);
}

static int dvb_dmx_swfilter_sectionfilter(struct dvb_demux_feed *feed,
                                          struct dvb_demux_filter *f)
{
        u8 neq = 0;
        int i;

        for (i = 0; i < DVB_DEMUX_MASK_MAX; i++) {
                u8 xor = f->filter.filter_value[i] ^ feed->feed.sec.secbuf[i];

                if (f->maskandmode[i] & xor)
                        return 0;

                neq |= f->maskandnotmode[i] & xor;
        }

        if (f->doneq && !neq)
                return 0;

        return feed->cb.sec(feed->feed.sec.secbuf, feed->feed.sec.seclen,
                            NULL, 0, &f->filter, &feed->buffer_flags);
}

static inline int dvb_dmx_swfilter_section_feed(struct dvb_demux_feed *feed)
{
        struct dvb_demux *demux = feed->demux;
        struct dvb_demux_filter *f = feed->filter;
        struct dmx_section_feed *sec = &feed->feed.sec;
        int section_syntax_indicator;

        if (!sec->is_filtering)
                return 0;

        if (!f)
                return 0;

        if (sec->check_crc) {
                section_syntax_indicator = ((sec->secbuf[1] & 0x80) != 0);
                if (section_syntax_indicator &&
                    demux->check_crc32(feed, sec->secbuf, sec->seclen)) {
                        set_buf_flags(feed, DMX_BUFFER_FLAG_HAD_CRC32_DISCARD);
                        return -1;
                }
        }

        do {
                if (dvb_dmx_swfilter_sectionfilter(feed, f) < 0)
                        return -1;
        } while ((f = f->next) && sec->is_filtering);

        sec->seclen = 0;

        return 0;
}

static void dvb_dmx_swfilter_section_new(struct dvb_demux_feed *feed)
{
        struct dmx_section_feed *sec = &feed->feed.sec;

        if (sec->secbufp < sec->tsfeedp) {
                int n = sec->tsfeedp - sec->secbufp;

                /*
                 * Section padding is done with 0xff bytes entirely.
                 * Due to speed reasons, we won't check all of them
                 * but just first and last.
                 */
                if (sec->secbuf[0] != 0xff || sec->secbuf[n - 1] != 0xff) {
                        set_buf_flags(feed,
                                      DMX_BUFFER_FLAG_DISCONTINUITY_DETECTED);
                        dprintk_sect_loss("section ts padding loss: %d/%d\n",
                                          n, sec->tsfeedp);
                        dprintk_sect_loss("pad data: %*ph\n", n, sec->secbuf);
                }
        }

        sec->tsfeedp = sec->secbufp = sec->seclen = 0;
        sec->secbuf = sec->secbuf_base;
}

/*
 * Losless Section Demux 1.4.1 by Emard
 * Valsecchi Patrick:
 *  - middle of section A  (no PUSI)
 *  - end of section A and start of section B
 *    (with PUSI pointing to the start of the second section)
 *
 *  In this case, without feed->pusi_seen you'll receive a garbage section
 *  consisting of the end of section A. Basically because tsfeedp
 *  is incemented and the use=0 condition is not raised
 *  when the second packet arrives.
 *
 * Fix:
 * when demux is started, let feed->pusi_seen = false to
 * prevent initial feeding of garbage from the end of
 * previous section. When you for the first time see PUSI=1
 * then set feed->pusi_seen = true
 */
static int dvb_dmx_swfilter_section_copy_dump(struct dvb_demux_feed *feed,
                                              const u8 *buf, u8 len)
{
        struct dvb_demux *demux = feed->demux;
        struct dmx_section_feed *sec = &feed->feed.sec;
        u16 limit, seclen, n;

        if (sec->tsfeedp >= DMX_MAX_SECFEED_SIZE)
                return 0;

        if (sec->tsfeedp + len > DMX_MAX_SECFEED_SIZE) {
                set_buf_flags(feed, DMX_BUFFER_FLAG_DISCONTINUITY_DETECTED);
                dprintk_sect_loss("section buffer full loss: %d/%d\n",
                                  sec->tsfeedp + len - DMX_MAX_SECFEED_SIZE,
                                  DMX_MAX_SECFEED_SIZE);
                len = DMX_MAX_SECFEED_SIZE - sec->tsfeedp;
        }

        if (len <= 0)
                return 0;

        demux->memcopy(feed, sec->secbuf_base + sec->tsfeedp, buf, len);
        sec->tsfeedp += len;

        /*
         * Dump all the sections we can find in the data (Emard)
         */
        limit = sec->tsfeedp;
        if (limit > DMX_MAX_SECFEED_SIZE)
                return -1;      /* internal error should never happen */

        /* to be sure always set secbuf */
        sec->secbuf = sec->secbuf_base + sec->secbufp;

        for (n = 0; sec->secbufp + 2 < limit; n++) {
                seclen = section_length(sec->secbuf);
                if (seclen <= 0 || seclen > DMX_MAX_SECTION_SIZE
                    || seclen + sec->secbufp > limit)
                        return 0;
                sec->seclen = seclen;
                sec->crc_val = ~0;
                /* dump [secbuf .. secbuf+seclen) */
                if (feed->pusi_seen) {
                        dvb_dmx_swfilter_section_feed(feed);
                } else {
                        set_buf_flags(feed,
                                      DMX_BUFFER_FLAG_DISCONTINUITY_DETECTED);
                        dprintk_sect_loss("pusi not seen, discarding section data\n");
                }
                sec->secbufp += seclen; /* secbufp and secbuf moving together is */
                sec->secbuf += seclen;  /* redundant but saves pointer arithmetic */
        }

        return 0;
}

static int dvb_dmx_swfilter_section_packet(struct dvb_demux_feed *feed,
                                           const u8 *buf)
{
        u8 p, count;
        int ccok, dc_i = 0;
        u8 cc;

        count = payload(buf);

        if (count == 0)         /* count == 0 if no payload or out of range */
                return -1;

        p = 188 - count;        /* payload start */

        cc = buf[3] & 0x0f;
        ccok = ((feed->cc + 1) & 0x0f) == cc;
        feed->cc = cc;

        if (buf[3] & 0x20) {
                /* adaption field present, check for discontinuity_indicator */
                if ((buf[4] > 0) && (buf[5] & 0x80))
                        dc_i = 1;
        }

        if (!ccok || dc_i) {
                if (dc_i) {
                        set_buf_flags(feed,
                                      DMX_BUFFER_FLAG_DISCONTINUITY_INDICATOR);
                        dprintk_sect_loss("%d frame with disconnect indicator\n",
                                cc);
                } else {
                        set_buf_flags(feed,
                                      DMX_BUFFER_FLAG_DISCONTINUITY_DETECTED);
                        dprintk_sect_loss("discontinuity: %d instead of %d. %d bytes lost\n",
                                cc, (feed->cc + 1) & 0x0f, count + 4);
                }
                /*
                 * those bytes under some circumstances will again be reported
                 * in the following dvb_dmx_swfilter_section_new
                 */

                /*
                 * Discontinuity detected. Reset pusi_seen to
                 * stop feeding of suspicious data until next PUSI=1 arrives
                 *
                 * FIXME: does it make sense if the MPEG-TS is the one
                 *      reporting discontinuity?
                 */

                feed->pusi_seen = false;
                dvb_dmx_swfilter_section_new(feed);
        }

        if (buf[1] & 0x40) {
                /* PUSI=1 (is set), section boundary is here */
                if (count > 1 && buf[p] < count) {
                        const u8 *before = &buf[p + 1];
                        u8 before_len = buf[p];
                        const u8 *after = &before[before_len];
                        u8 after_len = count - 1 - before_len;

                        dvb_dmx_swfilter_section_copy_dump(feed, before,
                                                           before_len);
                        /* before start of new section, set pusi_seen */
                        feed->pusi_seen = true;
                        dvb_dmx_swfilter_section_new(feed);
                        dvb_dmx_swfilter_section_copy_dump(feed, after,
                                                           after_len);
                } else if (count > 0) {
                        set_buf_flags(feed,
                                      DMX_BUFFER_FLAG_DISCONTINUITY_DETECTED);
                        dprintk_sect_loss("PUSI=1 but %d bytes lost\n", count);
                }
        } else {
                /* PUSI=0 (is not set), no section boundary */
                dvb_dmx_swfilter_section_copy_dump(feed, &buf[p], count);
        }

        return 0;
}

static inline void dvb_dmx_swfilter_packet_type(struct dvb_demux_feed *feed,
                                                const u8 *buf)
{
        switch (feed->type) {
        case DMX_TYPE_TS:
                if (!feed->feed.ts.is_filtering)
                        break;
                if (feed->ts_type & TS_PACKET) {
                        if (feed->ts_type & TS_PAYLOAD_ONLY)
                                dvb_dmx_swfilter_payload(feed, buf);
                        else
                                feed->cb.ts(buf, 188, NULL, 0, &feed->feed.ts,
                                            &feed->buffer_flags);
                }
                /* Used only on full-featured devices */
                if (feed->ts_type & TS_DECODER)
                        if (feed->demux->write_to_decoder)
                                feed->demux->write_to_decoder(feed, buf, 188);
                break;

        case DMX_TYPE_SEC:
                if (!feed->feed.sec.is_filtering)
                        break;
                if (dvb_dmx_swfilter_section_packet(feed, buf) < 0)
                        feed->feed.sec.seclen = feed->feed.sec.secbufp = 0;
                break;

        default:
                break;
        }
}

#define DVR_FEED(f)                                                     \
        (((f)->type == DMX_TYPE_TS) &&                                  \
        ((f)->feed.ts.is_filtering) &&                                  \
        (((f)->ts_type & (TS_PACKET | TS_DEMUX)) == TS_PACKET))

static void dvb_dmx_swfilter_packet(struct dvb_demux *demux, const u8 *buf)
{
        struct dvb_demux_feed *feed;
        u16 pid = ts_pid(buf);
        int dvr_done = 0;

        if (dvb_demux_speedcheck) {
                ktime_t cur_time;
                u64 speed_bytes, speed_timedelta;

                demux->speed_pkts_cnt++;

                /* show speed every SPEED_PKTS_INTERVAL packets */
                if (!(demux->speed_pkts_cnt % SPEED_PKTS_INTERVAL)) {
                        cur_time = ktime_get();

                        if (ktime_to_ns(demux->speed_last_time) != 0) {
                                speed_bytes = (u64)demux->speed_pkts_cnt
                                        * 188 * 8;
                                /* convert to 1024 basis */
                                speed_bytes = 1000 * div64_u64(speed_bytes,
                                                1024);
                                speed_timedelta = ktime_ms_delta(cur_time,
                                                        demux->speed_last_time);
                                if (speed_timedelta)
                                        dprintk("TS speed %llu Kbits/sec \n",
                                                div64_u64(speed_bytes,
                                                          speed_timedelta));
                        }

                        demux->speed_last_time = cur_time;
                        demux->speed_pkts_cnt = 0;
                }
        }

        if (buf[1] & 0x80) {
                list_for_each_entry(feed, &demux->feed_list, list_head) {
                        if ((feed->pid != pid) && (feed->pid != 0x2000))
                                continue;
                        set_buf_flags(feed, DMX_BUFFER_FLAG_TEI);
                }
                dprintk_tscheck("TEI detected. PID=0x%x data1=0x%x\n",
                                pid, buf[1]);
                /* data in this packet can't be trusted - drop it unless
                 * module option dvb_demux_feed_err_pkts is set */
                if (!dvb_demux_feed_err_pkts)
                        return;
        } else /* if TEI bit is set, pid may be wrong- skip pkt counter */
                if (demux->cnt_storage && dvb_demux_tscheck) {
                        /* check pkt counter */
                        if (pid < MAX_PID) {
                                if (buf[3] & 0x10)
                                        demux->cnt_storage[pid] =
                                                (demux->cnt_storage[pid] + 1) & 0xf;

                                if ((buf[3] & 0xf) != demux->cnt_storage[pid]) {
                                        list_for_each_entry(feed, &demux->feed_list, list_head) {
                                                if ((feed->pid != pid) && (feed->pid != 0x2000))
                                                        continue;
                                                set_buf_flags(feed,
                                                              DMX_BUFFER_PKT_COUNTER_MISMATCH);
                                        }

                                        dprintk_tscheck("TS packet counter mismatch. PID=0x%x expected 0x%x got 0x%x\n",
                                                        pid, demux->cnt_storage[pid],
                                                        buf[3] & 0xf);
                                        demux->cnt_storage[pid] = buf[3] & 0xf;
                                }
                        }
                        /* end check */
                }

        list_for_each_entry(feed, &demux->feed_list, list_head) {
                if ((feed->pid != pid) && (feed->pid != 0x2000))
                        continue;

                /* copy each packet only once to the dvr device, even
                 * if a PID is in multiple filters (e.g. video + PCR) */
                if ((DVR_FEED(feed)) && (dvr_done++))
                        continue;

                if (feed->pid == pid)
                        dvb_dmx_swfilter_packet_type(feed, buf);
                else if (feed->pid == 0x2000)
                        feed->cb.ts(buf, 188, NULL, 0, &feed->feed.ts,
                                    &feed->buffer_flags);
        }
}

void dvb_dmx_swfilter_packets(struct dvb_demux *demux, const u8 *buf,
                              size_t count)
{
        unsigned long flags;

        spin_lock_irqsave(&demux->lock, flags);

        while (count--) {
                if (buf[0] == 0x47)
                        dvb_dmx_swfilter_packet(demux, buf);
                buf += 188;
        }

        spin_unlock_irqrestore(&demux->lock, flags);
}

EXPORT_SYMBOL(dvb_dmx_swfilter_packets);

static inline int find_next_packet(const u8 *buf, int pos, size_t count,
                                   const int pktsize)
{
        int start = pos, lost;

        while (pos < count) {
                if (buf[pos] == 0x47 ||
                    (pktsize == 204 && buf[pos] == 0xB8))
                        break;
                pos++;
        }

        lost = pos - start;
        if (lost) {
                /* This garbage is part of a valid packet? */
                int backtrack = pos - pktsize;
                if (backtrack >= 0 && (buf[backtrack] == 0x47 ||
                    (pktsize == 204 && buf[backtrack] == 0xB8)))
                        return backtrack;
        }

        return pos;
}

/* Filter all pktsize= 188 or 204 sized packets and skip garbage. */
static inline void _dvb_dmx_swfilter(struct dvb_demux *demux, const u8 *buf,
                size_t count, const int pktsize)
{
        int p = 0, i, j;
        const u8 *q;
        unsigned long flags;

        spin_lock_irqsave(&demux->lock, flags);

        if (demux->tsbufp) { /* tsbuf[0] is now 0x47. */
                i = demux->tsbufp;
                j = pktsize - i;
                if (count < j) {
                        memcpy(&demux->tsbuf[i], buf, count);
                        demux->tsbufp += count;
                        goto bailout;
                }
                memcpy(&demux->tsbuf[i], buf, j);
                if (demux->tsbuf[0] == 0x47) /* double check */
                        dvb_dmx_swfilter_packet(demux, demux->tsbuf);
                demux->tsbufp = 0;
                p += j;
        }

        while (1) {
                p = find_next_packet(buf, p, count, pktsize);
                if (p >= count)
                        break;
                if (count - p < pktsize)
                        break;

                q = &buf[p];

                if (pktsize == 204 && (*q == 0xB8)) {
                        memcpy(demux->tsbuf, q, 188);
                        demux->tsbuf[0] = 0x47;
                        q = demux->tsbuf;
                }
                dvb_dmx_swfilter_packet(demux, q);
                p += pktsize;
        }

        i = count - p;
        if (i) {
                memcpy(demux->tsbuf, &buf[p], i);
                demux->tsbufp = i;
                if (pktsize == 204 && demux->tsbuf[0] == 0xB8)
                        demux->tsbuf[0] = 0x47;
        }

bailout:
        spin_unlock_irqrestore(&demux->lock, flags);
}

void dvb_dmx_swfilter(struct dvb_demux *demux, const u8 *buf, size_t count)
{
        _dvb_dmx_swfilter(demux, buf, count, 188);
}
EXPORT_SYMBOL(dvb_dmx_swfilter);

void dvb_dmx_swfilter_204(struct dvb_demux *demux, const u8 *buf, size_t count)
{
        _dvb_dmx_swfilter(demux, buf, count, 204);
}
EXPORT_SYMBOL(dvb_dmx_swfilter_204);

void dvb_dmx_swfilter_raw(struct dvb_demux *demux, const u8 *buf, size_t count)
{
        unsigned long flags;

        spin_lock_irqsave(&demux->lock, flags);

        demux->feed->cb.ts(buf, count, NULL, 0, &demux->feed->feed.ts,
                           &demux->feed->buffer_flags);

        spin_unlock_irqrestore(&demux->lock, flags);
}
EXPORT_SYMBOL(dvb_dmx_swfilter_raw);

static struct dvb_demux_filter *dvb_dmx_filter_alloc(struct dvb_demux *demux)
{
        int i;

        for (i = 0; i < demux->filternum; i++)
                if (demux->filter[i].state == DMX_STATE_FREE)
                        break;

        if (i == demux->filternum)
                return NULL;

        demux->filter[i].state = DMX_STATE_ALLOCATED;

        return &demux->filter[i];
}

static struct dvb_demux_feed *dvb_dmx_feed_alloc(struct dvb_demux *demux)
{
        int i;

        for (i = 0; i < demux->feednum; i++)
                if (demux->feed[i].state == DMX_STATE_FREE)
                        break;

        if (i == demux->feednum)
                return NULL;

        demux->feed[i].state = DMX_STATE_ALLOCATED;

        return &demux->feed[i];
}

static int dvb_demux_feed_find(struct dvb_demux_feed *feed)
{
        struct dvb_demux_feed *entry;

        list_for_each_entry(entry, &feed->demux->feed_list, list_head)
                if (entry == feed)
                        return 1;

        return 0;
}

static void dvb_demux_feed_add(struct dvb_demux_feed *feed)
{
        spin_lock_irq(&feed->demux->lock);
        if (dvb_demux_feed_find(feed)) {
                pr_err("%s: feed already in list (type=%x state=%x pid=%x)\n",
                       __func__, feed->type, feed->state, feed->pid);
                goto out;
        }

        list_add(&feed->list_head, &feed->demux->feed_list);
out:
        spin_unlock_irq(&feed->demux->lock);
}

static void dvb_demux_feed_del(struct dvb_demux_feed *feed)
{
        spin_lock_irq(&feed->demux->lock);
        if (!(dvb_demux_feed_find(feed))) {
                pr_err("%s: feed not in list (type=%x state=%x pid=%x)\n",
                       __func__, feed->type, feed->state, feed->pid);
                goto out;
        }

        list_del(&feed->list_head);
out:
        spin_unlock_irq(&feed->demux->lock);
}

static int dmx_ts_feed_set(struct dmx_ts_feed *ts_feed, u16 pid, int ts_type,
                           enum dmx_ts_pes pes_type, ktime_t timeout)
{
        struct dvb_demux_feed *feed = (struct dvb_demux_feed *)ts_feed;
        struct dvb_demux *demux = feed->demux;

        if (pid > DMX_MAX_PID)
                return -EINVAL;

        if (mutex_lock_interruptible(&demux->mutex))
                return -ERESTARTSYS;

        if (ts_type & TS_DECODER) {
                if (pes_type >= DMX_PES_OTHER) {
                        mutex_unlock(&demux->mutex);
                        return -EINVAL;
                }

                if (demux->pesfilter[pes_type] &&
                    demux->pesfilter[pes_type] != feed) {
                        mutex_unlock(&demux->mutex);
                        return -EINVAL;
                }

                demux->pesfilter[pes_type] = feed;
                demux->pids[pes_type] = pid;
        }

        dvb_demux_feed_add(feed);

        feed->pid = pid;
        feed->timeout = timeout;
        feed->ts_type = ts_type;
        feed->pes_type = pes_type;

        feed->state = DMX_STATE_READY;
        mutex_unlock(&demux->mutex);

        return 0;
}

static int dmx_ts_feed_start_filtering(struct dmx_ts_feed *ts_feed)
{
        struct dvb_demux_feed *feed = (struct dvb_demux_feed *)ts_feed;
        struct dvb_demux *demux = feed->demux;
        int ret;

        if (mutex_lock_interruptible(&demux->mutex))
                return -ERESTARTSYS;

        if (feed->state != DMX_STATE_READY || feed->type != DMX_TYPE_TS) {
                mutex_unlock(&demux->mutex);
                return -EINVAL;
        }

        if (!demux->start_feed) {
                mutex_unlock(&demux->mutex);
                return -ENODEV;
        }

        if ((ret = demux->start_feed(feed)) < 0) {
                mutex_unlock(&demux->mutex);
                return ret;
        }

        spin_lock_irq(&demux->lock);
        ts_feed->is_filtering = 1;
        feed->state = DMX_STATE_GO;
        spin_unlock_irq(&demux->lock);
        mutex_unlock(&demux->mutex);

        return 0;
}

static int dmx_ts_feed_stop_filtering(struct dmx_ts_feed *ts_feed)
{
        struct dvb_demux_feed *feed = (struct dvb_demux_feed *)ts_feed;
        struct dvb_demux *demux = feed->demux;
        int ret;

        mutex_lock(&demux->mutex);

        if (feed->state < DMX_STATE_GO) {
                mutex_unlock(&demux->mutex);
                return -EINVAL;
        }

        if (!demux->stop_feed) {
                mutex_unlock(&demux->mutex);
                return -ENODEV;
        }

        ret = demux->stop_feed(feed);

        spin_lock_irq(&demux->lock);
        ts_feed->is_filtering = 0;
        feed->state = DMX_STATE_ALLOCATED;
        spin_unlock_irq(&demux->lock);
        mutex_unlock(&demux->mutex);

        return ret;
}

static int dvbdmx_allocate_ts_feed(struct dmx_demux *dmx,
                                   struct dmx_ts_feed **ts_feed,
                                   dmx_ts_cb callback)
{
        struct dvb_demux *demux = (struct dvb_demux *)dmx;
        struct dvb_demux_feed *feed;

        if (mutex_lock_interruptible(&demux->mutex))
                return -ERESTARTSYS;

        if (!(feed = dvb_dmx_feed_alloc(demux))) {
                mutex_unlock(&demux->mutex);
                return -EBUSY;
        }

        feed->type = DMX_TYPE_TS;
        feed->cb.ts = callback;
        feed->demux = demux;
        feed->pid = 0xffff;
        feed->peslen = 0xfffa;
        feed->buffer_flags = 0;

        (*ts_feed) = &feed->feed.ts;
        (*ts_feed)->parent = dmx;
        (*ts_feed)->priv = NULL;
        (*ts_feed)->is_filtering = 0;
        (*ts_feed)->start_filtering = dmx_ts_feed_start_filtering;
        (*ts_feed)->stop_filtering = dmx_ts_feed_stop_filtering;
        (*ts_feed)->set = dmx_ts_feed_set;

        if (!(feed->filter = dvb_dmx_filter_alloc(demux))) {
                feed->state = DMX_STATE_FREE;
                mutex_unlock(&demux->mutex);
                return -EBUSY;
        }

        feed->filter->type = DMX_TYPE_TS;
        feed->filter->feed = feed;
        feed->filter->state = DMX_STATE_READY;

        mutex_unlock(&demux->mutex);

        return 0;
}

static int dvbdmx_release_ts_feed(struct dmx_demux *dmx,
                                  struct dmx_ts_feed *ts_feed)
{
        struct dvb_demux *demux = (struct dvb_demux *)dmx;
        struct dvb_demux_feed *feed = (struct dvb_demux_feed *)ts_feed;

        mutex_lock(&demux->mutex);

        if (feed->state == DMX_STATE_FREE) {
                mutex_unlock(&demux->mutex);
                return -EINVAL;
        }

        feed->state = DMX_STATE_FREE;
        feed->filter->state = DMX_STATE_FREE;

        dvb_demux_feed_del(feed);

        feed->pid = 0xffff;

        if (feed->ts_type & TS_DECODER && feed->pes_type < DMX_PES_OTHER)
                demux->pesfilter[feed->pes_type] = NULL;

        mutex_unlock(&demux->mutex);
        return 0;
}

/******************************************************************************
 * dmx_section_feed API calls
 ******************************************************************************/

static int dmx_section_feed_allocate_filter(struct dmx_section_feed *feed,
                                            struct dmx_section_filter **filter)
{
        struct dvb_demux_feed *dvbdmxfeed = (struct dvb_demux_feed *)feed;
        struct dvb_demux *dvbdemux = dvbdmxfeed->demux;
        struct dvb_demux_filter *dvbdmxfilter;

        if (mutex_lock_interruptible(&dvbdemux->mutex))
                return -ERESTARTSYS;

        dvbdmxfilter = dvb_dmx_filter_alloc(dvbdemux);
        if (!dvbdmxfilter) {
                mutex_unlock(&dvbdemux->mutex);
                return -EBUSY;
        }

        spin_lock_irq(&dvbdemux->lock);
        *filter = &dvbdmxfilter->filter;
        (*filter)->parent = feed;
        (*filter)->priv = NULL;
        dvbdmxfilter->feed = dvbdmxfeed;
        dvbdmxfilter->type = DMX_TYPE_SEC;
        dvbdmxfilter->state = DMX_STATE_READY;
        dvbdmxfilter->next = dvbdmxfeed->filter;
        dvbdmxfeed->filter = dvbdmxfilter;
        spin_unlock_irq(&dvbdemux->lock);

        mutex_unlock(&dvbdemux->mutex);
        return 0;
}

static int dmx_section_feed_set(struct dmx_section_feed *feed,
                                u16 pid, int check_crc)
{
        struct dvb_demux_feed *dvbdmxfeed = (struct dvb_demux_feed *)feed;
        struct dvb_demux *dvbdmx = dvbdmxfeed->demux;

        if (pid > 0x1fff)
                return -EINVAL;

        if (mutex_lock_interruptible(&dvbdmx->mutex))
                return -ERESTARTSYS;

        dvb_demux_feed_add(dvbdmxfeed);

        dvbdmxfeed->pid = pid;
        dvbdmxfeed->feed.sec.check_crc = check_crc;

        dvbdmxfeed->state = DMX_STATE_READY;
        mutex_unlock(&dvbdmx->mutex);
        return 0;
}

static void prepare_secfilters(struct dvb_demux_feed *dvbdmxfeed)
{
        int i;
        struct dvb_demux_filter *f;
        struct dmx_section_filter *sf;
        u8 mask, mode, doneq;

        if (!(f = dvbdmxfeed->filter))
                return;
        do {
                sf = &f->filter;
                doneq = false;
                for (i = 0; i < DVB_DEMUX_MASK_MAX; i++) {
                        mode = sf->filter_mode[i];
                        mask = sf->filter_mask[i];
                        f->maskandmode[i] = mask & mode;
                        doneq |= f->maskandnotmode[i] = mask & ~mode;
                }
                f->doneq = doneq ? true : false;
        } while ((f = f->next));
}

static int dmx_section_feed_start_filtering(struct dmx_section_feed *feed)
{
        struct dvb_demux_feed *dvbdmxfeed = (struct dvb_demux_feed *)feed;
        struct dvb_demux *dvbdmx = dvbdmxfeed->demux;
        int ret;

        if (mutex_lock_interruptible(&dvbdmx->mutex))
                return -ERESTARTSYS;

        if (feed->is_filtering) {
                mutex_unlock(&dvbdmx->mutex);
                return -EBUSY;
        }

        if (!dvbdmxfeed->filter) {
                mutex_unlock(&dvbdmx->mutex);
                return -EINVAL;
        }

        dvbdmxfeed->feed.sec.tsfeedp = 0;
        dvbdmxfeed->feed.sec.secbuf = dvbdmxfeed->feed.sec.secbuf_base;
        dvbdmxfeed->feed.sec.secbufp = 0;
        dvbdmxfeed->feed.sec.seclen = 0;
        dvbdmxfeed->pusi_seen = false;

        if (!dvbdmx->start_feed) {
                mutex_unlock(&dvbdmx->mutex);
                return -ENODEV;
        }

        prepare_secfilters(dvbdmxfeed);

        if ((ret = dvbdmx->start_feed(dvbdmxfeed)) < 0) {
                mutex_unlock(&dvbdmx->mutex);
                return ret;
        }

        spin_lock_irq(&dvbdmx->lock);
        feed->is_filtering = 1;
        dvbdmxfeed->state = DMX_STATE_GO;
        spin_unlock_irq(&dvbdmx->lock);

        mutex_unlock(&dvbdmx->mutex);
        return 0;
}

static int dmx_section_feed_stop_filtering(struct dmx_section_feed *feed)
{
        struct dvb_demux_feed *dvbdmxfeed = (struct dvb_demux_feed *)feed;
        struct dvb_demux *dvbdmx = dvbdmxfeed->demux;

        int ret;

        mutex_lock(&dvbdmx->mutex);

        if (!dvbdmx->stop_feed) {
                mutex_unlock(&dvbdmx->mutex);
                return -ENODEV;
        }

        ret = dvbdmx->stop_feed(dvbdmxfeed);

        spin_lock_irq(&dvbdmx->lock);
        dvbdmxfeed->state = DMX_STATE_READY;
        feed->is_filtering = 0;
        spin_unlock_irq(&dvbdmx->lock);

        mutex_unlock(&dvbdmx->mutex);
        return ret;
}

static int dmx_section_feed_release_filter(struct dmx_section_feed *feed,
                                           struct dmx_section_filter *filter)
{
        struct dvb_demux_filter *dvbdmxfilter = (struct dvb_demux_filter *)filter, *f;
        struct dvb_demux_feed *dvbdmxfeed = (struct dvb_demux_feed *)feed;
        struct dvb_demux *dvbdmx = dvbdmxfeed->demux;

        mutex_lock(&dvbdmx->mutex);

        if (dvbdmxfilter->feed != dvbdmxfeed) {
                mutex_unlock(&dvbdmx->mutex);
                return -EINVAL;
        }

        if (feed->is_filtering) {
                /* release dvbdmx->mutex as far as it is
                   acquired by stop_filtering() itself */
                mutex_unlock(&dvbdmx->mutex);
                feed->stop_filtering(feed);
                mutex_lock(&dvbdmx->mutex);
        }

        spin_lock_irq(&dvbdmx->lock);
        f = dvbdmxfeed->filter;

        if (f == dvbdmxfilter) {
                dvbdmxfeed->filter = dvbdmxfilter->next;
        } else {
                while (f->next != dvbdmxfilter)
                        f = f->next;
                f->next = f->next->next;
        }

        dvbdmxfilter->state = DMX_STATE_FREE;
        spin_unlock_irq(&dvbdmx->lock);
        mutex_unlock(&dvbdmx->mutex);
        return 0;
}

static int dvbdmx_allocate_section_feed(struct dmx_demux *demux,
                                        struct dmx_section_feed **feed,
                                        dmx_section_cb callback)
{
        struct dvb_demux *dvbdmx = (struct dvb_demux *)demux;
        struct dvb_demux_feed *dvbdmxfeed;

        if (mutex_lock_interruptible(&dvbdmx->mutex))
                return -ERESTARTSYS;

        if (!(dvbdmxfeed = dvb_dmx_feed_alloc(dvbdmx))) {
                mutex_unlock(&dvbdmx->mutex);
                return -EBUSY;
        }

        dvbdmxfeed->type = DMX_TYPE_SEC;
        dvbdmxfeed->cb.sec = callback;
        dvbdmxfeed->demux = dvbdmx;
        dvbdmxfeed->pid = 0xffff;
        dvbdmxfeed->buffer_flags = 0;
        dvbdmxfeed->feed.sec.secbuf = dvbdmxfeed->feed.sec.secbuf_base;
        dvbdmxfeed->feed.sec.secbufp = dvbdmxfeed->feed.sec.seclen = 0;
        dvbdmxfeed->feed.sec.tsfeedp = 0;
        dvbdmxfeed->filter = NULL;

        (*feed) = &dvbdmxfeed->feed.sec;
        (*feed)->is_filtering = 0;
        (*feed)->parent = demux;
        (*feed)->priv = NULL;

        (*feed)->set = dmx_section_feed_set;
        (*feed)->allocate_filter = dmx_section_feed_allocate_filter;
        (*feed)->start_filtering = dmx_section_feed_start_filtering;
        (*feed)->stop_filtering = dmx_section_feed_stop_filtering;
        (*feed)->release_filter = dmx_section_feed_release_filter;

        mutex_unlock(&dvbdmx->mutex);
        return 0;
}

static int dvbdmx_release_section_feed(struct dmx_demux *demux,
                                       struct dmx_section_feed *feed)
{
        struct dvb_demux_feed *dvbdmxfeed = (struct dvb_demux_feed *)feed;
        struct dvb_demux *dvbdmx = (struct dvb_demux *)demux;

        mutex_lock(&dvbdmx->mutex);

        if (dvbdmxfeed->state == DMX_STATE_FREE) {
                mutex_unlock(&dvbdmx->mutex);
                return -EINVAL;
        }
        dvbdmxfeed->state = DMX_STATE_FREE;

        dvb_demux_feed_del(dvbdmxfeed);

        dvbdmxfeed->pid = 0xffff;

        mutex_unlock(&dvbdmx->mutex);
        return 0;
}

/******************************************************************************
 * dvb_demux kernel data API calls
 ******************************************************************************/

static int dvbdmx_open(struct dmx_demux *demux)
{
        struct dvb_demux *dvbdemux = (struct dvb_demux *)demux;

        if (dvbdemux->users >= MAX_DVB_DEMUX_USERS)
                return -EUSERS;

        dvbdemux->users++;
        return 0;
}

static int dvbdmx_close(struct dmx_demux *demux)
{
        struct dvb_demux *dvbdemux = (struct dvb_demux *)demux;

        if (dvbdemux->users == 0)
                return -ENODEV;

        dvbdemux->users--;
        //FIXME: release any unneeded resources if users==0
        return 0;
}

static int dvbdmx_write(struct dmx_demux *demux, const char __user *buf, size_t count)
{
        struct dvb_demux *dvbdemux = (struct dvb_demux *)demux;
        void *p;

        if ((!demux->frontend) || (demux->frontend->source != DMX_MEMORY_FE))
                return -EINVAL;

        p = memdup_user(buf, count);
        if (IS_ERR(p))
                return PTR_ERR(p);
        if (mutex_lock_interruptible(&dvbdemux->mutex)) {
                kfree(p);
                return -ERESTARTSYS;
        }
        dvb_dmx_swfilter(dvbdemux, p, count);
        kfree(p);
        mutex_unlock(&dvbdemux->mutex);

        if (signal_pending(current))
                return -EINTR;
        return count;
}

static int dvbdmx_add_frontend(struct dmx_demux *demux,
                               struct dmx_frontend *frontend)
{
        struct dvb_demux *dvbdemux = (struct dvb_demux *)demux;
        struct list_head *head = &dvbdemux->frontend_list;

        list_add(&(frontend->connectivity_list), head);

        return 0;
}

static int dvbdmx_remove_frontend(struct dmx_demux *demux,
                                  struct dmx_frontend *frontend)
{
        struct dvb_demux *dvbdemux = (struct dvb_demux *)demux;
        struct list_head *pos, *n, *head = &dvbdemux->frontend_list;

        list_for_each_safe(pos, n, head) {
                if (DMX_FE_ENTRY(pos) == frontend) {
                        list_del(pos);
                        return 0;
                }
        }

        return -ENODEV;
}

static struct list_head *dvbdmx_get_frontends(struct dmx_demux *demux)
{
        struct dvb_demux *dvbdemux = (struct dvb_demux *)demux;

        if (list_empty(&dvbdemux->frontend_list))
                return NULL;

        return &dvbdemux->frontend_list;
}

static int dvbdmx_connect_frontend(struct dmx_demux *demux,
                                   struct dmx_frontend *frontend)
{
        struct dvb_demux *dvbdemux = (struct dvb_demux *)demux;

        if (demux->frontend)
                return -EINVAL;

        mutex_lock(&dvbdemux->mutex);

        demux->frontend = frontend;
        mutex_unlock(&dvbdemux->mutex);
        return 0;
}

static int dvbdmx_disconnect_frontend(struct dmx_demux *demux)
{
        struct dvb_demux *dvbdemux = (struct dvb_demux *)demux;

        mutex_lock(&dvbdemux->mutex);

        demux->frontend = NULL;
        mutex_unlock(&dvbdemux->mutex);
        return 0;
}

static int dvbdmx_get_pes_pids(struct dmx_demux *demux, u16 * pids)
{
        struct dvb_demux *dvbdemux = (struct dvb_demux *)demux;

        memcpy(pids, dvbdemux->pids, 5 * sizeof(u16));
        return 0;
}

int dvb_dmx_init(struct dvb_demux *dvbdemux)
{
        int i;
        struct dmx_demux *dmx = &dvbdemux->dmx;

        dvbdemux->cnt_storage = NULL;
        dvbdemux->users = 0;
        dvbdemux->filter = vmalloc(array_size(sizeof(struct dvb_demux_filter),
                                              dvbdemux->filternum));

        if (!dvbdemux->filter)
                return -ENOMEM;

        dvbdemux->feed = vmalloc(array_size(sizeof(struct dvb_demux_feed),
                                            dvbdemux->feednum));
        if (!dvbdemux->feed) {
                vfree(dvbdemux->filter);
                dvbdemux->filter = NULL;
                return -ENOMEM;
        }
        for (i = 0; i < dvbdemux->filternum; i++) {
                dvbdemux->filter[i].state = DMX_STATE_FREE;
                dvbdemux->filter[i].index = i;
        }
        for (i = 0; i < dvbdemux->feednum; i++) {
                dvbdemux->feed[i].state = DMX_STATE_FREE;
                dvbdemux->feed[i].index = i;
        }

        dvbdemux->cnt_storage = vmalloc(MAX_PID + 1);
        if (!dvbdemux->cnt_storage)
                pr_warn("Couldn't allocate memory for TS/TEI check. Disabling it\n");

        INIT_LIST_HEAD(&dvbdemux->frontend_list);

        for (i = 0; i < DMX_PES_OTHER; i++) {
                dvbdemux->pesfilter[i] = NULL;
                dvbdemux->pids[i] = 0xffff;
        }

        INIT_LIST_HEAD(&dvbdemux->feed_list);

        dvbdemux->playing = 0;
        dvbdemux->recording = 0;
        dvbdemux->tsbufp = 0;

        if (!dvbdemux->check_crc32)
                dvbdemux->check_crc32 = dvb_dmx_crc32;

        if (!dvbdemux->memcopy)
                dvbdemux->memcopy = dvb_dmx_memcopy;

        dmx->frontend = NULL;
        dmx->priv = dvbdemux;
        dmx->open = dvbdmx_open;
        dmx->close = dvbdmx_close;
        dmx->write = dvbdmx_write;
        dmx->allocate_ts_feed = dvbdmx_allocate_ts_feed;
        dmx->release_ts_feed = dvbdmx_release_ts_feed;
        dmx->allocate_section_feed = dvbdmx_allocate_section_feed;
        dmx->release_section_feed = dvbdmx_release_section_feed;

        dmx->add_frontend = dvbdmx_add_frontend;
        dmx->remove_frontend = dvbdmx_remove_frontend;
        dmx->get_frontends = dvbdmx_get_frontends;
        dmx->connect_frontend = dvbdmx_connect_frontend;
        dmx->disconnect_frontend = dvbdmx_disconnect_frontend;
        dmx->get_pes_pids = dvbdmx_get_pes_pids;

        mutex_init(&dvbdemux->mutex);
        spin_lock_init(&dvbdemux->lock);

        return 0;
}

EXPORT_SYMBOL(dvb_dmx_init);

void dvb_dmx_release(struct dvb_demux *dvbdemux)
{
        vfree(dvbdemux->cnt_storage);
        vfree(dvbdemux->filter);
        vfree(dvbdemux->feed);
}

EXPORT_SYMBOL(dvb_dmx_release);