/* $NetBSD: dtv_buffer.c,v 1.9 2018/09/03 16:29:30 riastradh Exp $ */

/*-
* Copyright (c) 2011 Jared D. McNeill <[email protected]>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
*    must display the following acknowledgement:
*        This product includes software developed by Jared D. McNeill.
* 4. Neither the name of The NetBSD Foundation nor the names of its
*    contributors may be used to endorse or promote products derived
*    from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: dtv_buffer.c,v 1.9 2018/09/03 16:29:30 riastradh Exp $");

#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/types.h>
#include <sys/conf.h>
#include <sys/device.h>
#include <sys/vnode.h>
#include <sys/poll.h>
#include <sys/select.h>

#include <dev/dtv/dtvvar.h>

#define BLOCK_SIZE      DTV_DEFAULT_BLOCKSIZE
#define BLOCK_ALIGN(a)  (((a) + BLOCK_SIZE - 1) & ~(BLOCK_SIZE - 1))

static void
dtv_buffer_write(struct dtv_softc *sc, const uint8_t *buf, size_t buflen)
{
       struct dtv_stream *ds = &sc->sc_stream;
       struct dtv_buffer *db;
       struct dtv_scatter_io sio;
       size_t resid = buflen, avail;
       off_t offset = 0;

       KASSERT(buflen == TS_PKTLEN);

       while (resid > 0) {
               mutex_enter(&ds->ds_ingress_lock);

               if (SIMPLEQ_EMPTY(&ds->ds_ingress)) {
                       aprint_debug_dev(sc->sc_dev,
                           "dropping sample (%zu)\n", resid);
                       mutex_exit(&ds->ds_ingress_lock);
                       return;
               }

               db = SIMPLEQ_FIRST(&ds->ds_ingress);
               mutex_exit(&ds->ds_ingress_lock);

               avail = uimin(db->db_length - db->db_bytesused, resid);
               if (dtv_scatter_io_init(&ds->ds_data,
                   db->db_offset + db->db_bytesused, avail, &sio)) {
                       dtv_scatter_io_copyin(&sio, buf + offset);
                       db->db_bytesused += (avail - sio.sio_resid);
                       offset += (avail - sio.sio_resid);
                       resid -= (avail - sio.sio_resid);
               }

               if (db->db_bytesused == db->db_length) {
                       mutex_enter(&ds->ds_ingress_lock);
                       SIMPLEQ_REMOVE_HEAD(&ds->ds_ingress, db_entries);
                       mutex_exit(&ds->ds_ingress_lock);
                       mutex_enter(&ds->ds_egress_lock);
                       SIMPLEQ_INSERT_TAIL(&ds->ds_egress, db, db_entries);
                       selnotify(&ds->ds_sel, 0, 0);
                       cv_broadcast(&ds->ds_sample_cv);
                       mutex_exit(&ds->ds_egress_lock);
               }
       }
}

void
dtv_buffer_submit(void *priv, const struct dtv_payload *payload)
{
       struct dtv_softc *sc = priv;
       struct dtv_ts *ts = &sc->sc_ts;
       const uint8_t *tspkt;
       unsigned int npkts, i;

       tspkt = payload->data;
       npkts = payload->size / TS_PKTLEN;
       for (i = 0; i < npkts; i++) {
               if (TS_HAS_SYNC(tspkt)) {
                       if (ts->ts_pidfilter[TS_PID(tspkt)]) {
                               dtv_buffer_write(sc, tspkt, TS_PKTLEN);
                       }
                       dtv_demux_write(sc, tspkt, TS_PKTLEN);
               }
               tspkt += TS_PKTLEN;
       }
}

static struct dtv_buffer *
dtv_buffer_alloc(void)
{
       return kmem_alloc(sizeof(struct dtv_buffer), KM_SLEEP);
}

static void
dtv_buffer_free(struct dtv_buffer *db)
{
       kmem_free(db, sizeof(*db));
}

int
dtv_buffer_realloc(struct dtv_softc *sc, size_t bufsize)
{
       struct dtv_stream *ds = &sc->sc_stream;
       unsigned int i, nbufs, oldnbufs, minnbufs;
       struct dtv_buffer **oldbuf;
       off_t offset;
       int error;

       nbufs = BLOCK_ALIGN(bufsize) / BLOCK_SIZE;

       error = dtv_scatter_buf_set_size(&ds->ds_data, bufsize);
       if (error)
               return error;

       oldnbufs = ds->ds_nbufs;
       oldbuf = ds->ds_buf;

       ds->ds_nbufs = nbufs;
       if (nbufs > 0) {
               ds->ds_buf = kmem_alloc(sizeof(struct dtv_buffer *) * nbufs,
                   KM_SLEEP);
       } else {
               ds->ds_buf = NULL;
       }

       minnbufs = uimin(nbufs, oldnbufs);
       for (i = 0; i < minnbufs; i++)
               ds->ds_buf[i] = oldbuf[i];
       for (; i < nbufs; i++)
               ds->ds_buf[i] = dtv_buffer_alloc();
       for (; i < oldnbufs; i++) {
               dtv_buffer_free(oldbuf[i]);
               oldbuf[i] = NULL;
       }
       if (oldbuf != NULL)
               kmem_free(oldbuf, sizeof(struct dtv_buffer *) * oldnbufs);

       offset = 0;
       for (i = 0; i < nbufs; i++) {
               ds->ds_buf[i]->db_offset = offset;
               ds->ds_buf[i]->db_bytesused = 0;
               ds->ds_buf[i]->db_length = BLOCK_SIZE;
               offset += BLOCK_SIZE;
       }

       return 0;
}

static struct dtv_buffer *
dtv_stream_dequeue(struct dtv_stream *ds)
{
       struct dtv_buffer *db;

       if (!SIMPLEQ_EMPTY(&ds->ds_egress)) {
               db = SIMPLEQ_FIRST(&ds->ds_egress);
               SIMPLEQ_REMOVE_HEAD(&ds->ds_egress, db_entries);
               return db;
       }

       return NULL;
}

static void
dtv_stream_enqueue(struct dtv_stream *ds, struct dtv_buffer *db)
{
       db->db_bytesused = 0;
       SIMPLEQ_INSERT_TAIL(&ds->ds_ingress, db, db_entries);
}

int
dtv_buffer_setup(struct dtv_softc *sc)
{
       struct dtv_stream *ds = &sc->sc_stream;
       unsigned int i;

       mutex_enter(&ds->ds_ingress_lock);
       for (i = 0; i < ds->ds_nbufs; i++)
               dtv_stream_enqueue(ds, ds->ds_buf[i]);
       mutex_exit(&ds->ds_ingress_lock);

       return 0;
}

int
dtv_buffer_destroy(struct dtv_softc *sc)
{
       struct dtv_stream *ds = &sc->sc_stream;

       mutex_enter(&ds->ds_ingress_lock);
       while (SIMPLEQ_FIRST(&ds->ds_ingress))
               SIMPLEQ_REMOVE_HEAD(&ds->ds_ingress, db_entries);
       mutex_exit(&ds->ds_ingress_lock);
       mutex_enter(&ds->ds_egress_lock);
       while (SIMPLEQ_FIRST(&ds->ds_egress))
               SIMPLEQ_REMOVE_HEAD(&ds->ds_egress, db_entries);
       mutex_exit(&ds->ds_egress_lock);

       return 0;
}

int
dtv_buffer_read(struct dtv_softc *sc, struct uio *uio, int flags)
{
       struct dtv_stream *ds = &sc->sc_stream;
       struct dtv_buffer *db;
       struct dtv_scatter_io sio;
       off_t offset;
       size_t len, bread = 0;
       int error;

       while (uio->uio_resid > 0) {
retry:
               mutex_enter(&ds->ds_egress_lock);
               while (SIMPLEQ_EMPTY(&ds->ds_egress)) {
                       if (flags & IO_NDELAY) {
                               mutex_exit(&ds->ds_egress_lock);
                               return EWOULDBLOCK;
                       }

                       error = cv_wait_sig(&ds->ds_sample_cv,
                           &ds->ds_egress_lock);
                       if (error) {
                               mutex_exit(&ds->ds_egress_lock);
                               return EINTR;
                       }
               }
               db = SIMPLEQ_FIRST(&ds->ds_egress);
               mutex_exit(&ds->ds_egress_lock);

               if (db->db_bytesused == 0) {
                       mutex_enter(&ds->ds_egress_lock);
                       db = dtv_stream_dequeue(ds);
                       mutex_exit(&ds->ds_egress_lock);
                       mutex_enter(&ds->ds_ingress_lock);
                       dtv_stream_enqueue(ds, db);
                       mutex_exit(&ds->ds_ingress_lock);
                       ds->ds_bytesread = 0;
                       goto retry;
               }

               len = uimin(uio->uio_resid, db->db_bytesused - ds->ds_bytesread);
               offset = db->db_offset + ds->ds_bytesread;

               if (dtv_scatter_io_init(&ds->ds_data, offset, len, &sio)) {
                       error = dtv_scatter_io_uiomove(&sio, uio);
                       if (error == EFAULT)
                               return EFAULT;
                       ds->ds_bytesread += (len - sio.sio_resid);
                       bread += (len - sio.sio_resid);
               }

               if (ds->ds_bytesread >= db->db_bytesused) {
                       mutex_enter(&ds->ds_egress_lock);
                       db = dtv_stream_dequeue(ds);
                       mutex_exit(&ds->ds_egress_lock);
                       mutex_enter(&ds->ds_ingress_lock);
                       dtv_stream_enqueue(ds, db);
                       mutex_exit(&ds->ds_ingress_lock);

                       ds->ds_bytesread = 0;
               }
       }

       return 0;
}

int
dtv_buffer_poll(struct dtv_softc *sc, int events, lwp_t *l)
{
       struct dtv_stream *ds = &sc->sc_stream;
       int revents = 0;
#ifdef DTV_BUFFER_DEBUG
       struct dtv_buffer *db;
       size_t bufsize = 0;
#endif

       mutex_enter(&ds->ds_egress_lock);
       if (!SIMPLEQ_EMPTY(&ds->ds_egress)) {
#ifdef DTV_BUFFER_DEBUG
               SIMPLEQ_FOREACH(db, &ds->ds_egress, db_entries)
                       bufsize += db->db_bytesused;
#endif
               revents |= (POLLIN | POLLOUT | POLLPRI);
       } else {
               selrecord(l, &ds->ds_sel);
       }
       mutex_exit(&ds->ds_egress_lock);

#ifdef DTV_BUFFER_DEBUG
       device_printf(sc->sc_dev, "%s: bufsize=%zu\n", __func__, bufsize);
#endif

       return revents;
}

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