targets/dcam1394/dcam_ring_buff.c

	dcam_ring_buff.c revision 8eea8e29cc4374d1ee24c25a07f45af132db3499
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

/*
 * dcam_ring_buff.c
 *
 * dcam1394 driver.  Video frame ring buffer support.
 */

#include <sys/types.h>
#include <sys/kmem.h>
#include <sys/ddidmareq.h>
#include <sys/types.h>
#include <sys/inttypes.h>
#include <sys/tnf_probe.h>
#include <sys/cmn_err.h>

#include <sys/1394/targets/dcam1394/dcam.h>

/*
 * ring_buff_create
 *
 *  - alloc ring_buff_t structure
 *  - init ring_buff's num_buffs, buff_num_bytes, num_read_ptrs,
 *        read_ptr_pos
 *  - alloc (num buffs) entries in ring_buff's buff_info_array_p
 *
 *  - for each buff
 *     - alloc DMA handle; store DMA handle in buff's buff_info_array_p
 *     - alloc mem for DMA transfer; store base addr, data access handle
 *           in buff's  buff_info_array_p entry
 *     - bind alloc'ed mem to DMA handle; store assoc info in buff's
 *           buff_info_array_p entry
 */
ring_buff_t *
ring_buff_create(dcam_state_t *softc_p, size_t num_buffs,
    size_t buff_num_bytes)
{
    buff_info_t *buff_info_p;
    size_t buff;
    int i, rc;
    ring_buff_t *ring_buff_p;
    size_t num_bytes;

    num_bytes = sizeof (ring_buff_t);

    ring_buff_p = (ring_buff_t *)kmem_alloc(num_bytes, KM_SLEEP);

    ring_buff_p->num_buffs      = num_buffs;
    ring_buff_p->buff_num_bytes = buff_num_bytes;
    ring_buff_p->write_ptr_pos  = 0;
    ring_buff_p->num_read_ptrs  = 0;
    ring_buff_p->read_ptr_incr_val  = 1;

    for (i = 0; i < MAX_NUM_READ_PTRS; i++) {
        ring_buff_p->read_ptr_pos[i] = (size_t)-1;
    }

    num_bytes = num_buffs * sizeof (buff_info_t);

    ring_buff_p->buff_info_array_p =
        (buff_info_t *)kmem_alloc(num_bytes, KM_SLEEP);

    for (buff = 0; buff < num_buffs; buff++) {

        buff_info_p = &(ring_buff_p->buff_info_array_p[buff]);

        if ((ddi_dma_alloc_handle(
            softc_p->dip,
            &softc_p->attachinfo.dma_attr,
            DDI_DMA_DONTWAIT,
            NULL,
            &(buff_info_p->dma_handle))) != DDI_SUCCESS) {
            ring_buff_free(softc_p, ring_buff_p);
            return (NULL);
        }

        if (ddi_dma_mem_alloc(
            buff_info_p->dma_handle,
            buff_num_bytes,
            &softc_p->attachinfo.acc_attr,
            DDI_DMA_STREAMING,
            DDI_DMA_DONTWAIT,
            (caddr_t)NULL,
            &(buff_info_p->kaddr_p),
            &(buff_info_p->real_len),
            &(buff_info_p->data_acc_handle)) != DDI_SUCCESS) {
            ring_buff_free(softc_p, ring_buff_p);

            /*
             *  Print a warning, this triggered the bug
             *  report #4423667.  This call can fail if
             *  the memory tests are being run in sunvts.
             *  The fact is, this code is doing the right
             *  thing.  I added an error message, so that
             *  future occurrences can be dealt with directly.
             *  This is not a bug... The vmem test in sunvts
             *  can eat up all swap/virtual memory.
             */
            cmn_err(CE_WARN,
                "ddi_dma_mem_alloc() failed in ring_buff_create(),"\
                " insufficient memory resources.\n");
            return (NULL);
        }

        rc = ddi_dma_addr_bind_handle(
            buff_info_p->dma_handle,
            (struct as *)NULL,
            (caddr_t)buff_info_p->kaddr_p,
            buff_info_p->real_len,
            DDI_DMA_RDWR | DDI_DMA_STREAMING,
            DDI_DMA_DONTWAIT,
            NULL,
            &buff_info_p->dma_cookie,
            &buff_info_p->dma_cookie_count);

        if (rc != DDI_DMA_MAPPED) {
            ring_buff_free(softc_p, ring_buff_p);
            return (NULL);
        }
    }

    return (ring_buff_p);
}


/*
 * ring_buff_free
 */
void
ring_buff_free(dcam_state_t *softc_p, ring_buff_t  *ring_buff_p)
{
    buff_info_t *buff_info_p;
    int i;

    if (ring_buff_p == NULL) {
        softc_p->ring_buff_p = NULL;
        return;
    }

    if (ring_buff_p->buff_info_array_p != NULL) {
        for (i = 0; i < ring_buff_p->num_buffs; i++) {

            buff_info_p = &(ring_buff_p->buff_info_array_p[i]);

            (void) ddi_dma_unbind_handle(buff_info_p->dma_handle);
            ddi_dma_mem_free(&buff_info_p->data_acc_handle);
            ddi_dma_free_handle(&buff_info_p->dma_handle);
        }

        kmem_free(ring_buff_p->buff_info_array_p,
            ring_buff_p->num_buffs * sizeof (buff_info_t));
    }

    kmem_free(ring_buff_p, sizeof (ring_buff_t));

    softc_p->ring_buff_p = NULL;
}


/*
 * ring_buff_read_ptr_add
 */
int
ring_buff_read_ptr_add(ring_buff_t *ring_buff_p)
{
    int i;
    int read_ptr_id;

    read_ptr_id = -1;

    for (i = 0; i < MAX_NUM_READ_PTRS; i++) {

        if (ring_buff_p->read_ptr_pos[i] == -1) {
            ring_buff_p->read_ptr_pos[i] = 0;
            read_ptr_id = i;
            break;
        }
    }

    return (read_ptr_id);
}


/*
 * ring_buff_read_ptr_remove
 */
int
ring_buff_read_ptr_remove(ring_buff_t *ring_buff_p, int read_ptr_id)
{
    ring_buff_p->read_ptr_pos[read_ptr_id] = (size_t)-1;

    return (0);
}


/*
 * ring_buff_read_ptr_buff_get
 *
 * Return pointer to buffer that a read pointer associated with the
 * ring buffer is pointing to.
 */
buff_info_t *
ring_buff_read_ptr_buff_get(ring_buff_t *ring_buff_p, int read_ptr_id)
{
    size_t      read_ptr_pos;
    buff_info_t *buff_info_p;

    read_ptr_pos = ring_buff_p->read_ptr_pos[read_ptr_id];
    buff_info_p  = &(ring_buff_p->buff_info_array_p[read_ptr_pos]);

    return (buff_info_p);
}


/*
 * ring_buff_read_ptr_pos_get
 */
size_t
ring_buff_read_ptr_pos_get(ring_buff_t *ring_buff_p, int read_ptr_id)
{
    return (ring_buff_p->read_ptr_pos[read_ptr_id]);
}


/*
 * ring_buff_read_ptr_incr
 */
void
ring_buff_read_ptr_incr(ring_buff_t *ring_buff_p, int read_ptr_id)
{
    size_t read_ptr_pos;
#if defined(_ADDL_RING_BUFF_CHECK)
    size_t lrp, lwp; /* linear read, write positions */
#endif  /* _ADDL_RING_BUFFER_CHECK */

    /*
     * increment the read pointer based on read_ptr_incr_val
     * which can vary from 1 to 10
     */

    /* get current read pointer pos */
    read_ptr_pos = ring_buff_p->read_ptr_pos[read_ptr_id];

    ring_buff_p->read_ptr_pos[read_ptr_id] =
        (read_ptr_pos + 1) % ring_buff_p->num_buffs;

#if defined(_ADDL_RING_BUFF_CHECK)
    if ((read_ptr_pos == 0) && (ring_buff_p->write_ptr_pos == 0)) {
        return;
    }

    if (read_ptr_pos < ring_buff_p->write_ptr_pos) {

        /* calculate new read pointer position */
        if ((read_ptr_pos + ring_buff_p->read_ptr_incr_val) <
            ring_buff_p->write_ptr_pos) {

            /* there is still some valid frame data */
            ring_buff_p->read_ptr_pos[read_ptr_id] =
                (read_ptr_pos +
                ring_buff_p->read_ptr_incr_val) %
                ring_buff_p->num_buffs;
        } else {
            /*
             * we have skipped beyond available frame
             * data, so the buffer is empty
             */
            ring_buff_p->read_ptr_pos[read_ptr_id] =
                ring_buff_p->write_ptr_pos;
        }
    } else {
        /*
         * since read pointer is ahead of write pointer,
         * it becomes easier to check for new read
         * pointer position if we pretend that our data
         * buffer is linear instead of circular
         */

        lrp = read_ptr_pos + ring_buff_p->read_ptr_incr_val;
        lwp = ring_buff_p->num_buffs +
            ring_buff_p->write_ptr_pos;

        if (lrp < lwp) {
            /* there is still some valid frame data */
            ring_buff_p->read_ptr_pos[read_ptr_id] =
                (read_ptr_pos +
                ring_buff_p->read_ptr_incr_val) %
                ring_buff_p->num_buffs;
        } else {
            /*
             * we have skipped beyond available
             * frame  data, so the buffer is empty
             */
            ring_buff_p->read_ptr_pos[read_ptr_id] =
                ring_buff_p->write_ptr_pos;
        }
    }
#endif  /* _ADDL_RING_BUFF_CHECK */
}


/*
 * ring_buff_write_ptr_pos_get
 */
size_t
ring_buff_write_ptr_pos_get(ring_buff_t *ring_buff_p)
{
    return (ring_buff_p->write_ptr_pos);
}


/*
 * ring_buff_write_ptr_incr
 */
void
ring_buff_write_ptr_incr(ring_buff_t *ring_buff_p)
{
    size_t write_ptr_pos;

    write_ptr_pos = ring_buff_p->write_ptr_pos;

    ring_buff_p->write_ptr_pos =
        ((write_ptr_pos + 1) % ring_buff_p->num_buffs);
}