vnic_wq_copy.h

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/*
 * Copyright 2008 Cisco Systems, Inc.  All rights reserved.
 * Copyright 2007 Nuova Systems, Inc.  All rights reserved.
 *
 * This program is free software; you may redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
#ifndef _VNIC_WQ_COPY_H_
#define _VNIC_WQ_COPY_H_

#include <linux/pci.h>
#include "vnic_wq.h"
#include "fcpio.h"

#define VNIC_WQ_COPY_MAX 1

struct vnic_wq_copy {
    unsigned int index;
    struct vnic_dev *vdev;
    struct vnic_wq_ctrl __iomem *ctrl;  /* memory-mapped */
    struct vnic_dev_ring ring;
    unsigned to_use_index;
    unsigned to_clean_index;
};

static inline unsigned int vnic_wq_copy_desc_avail(struct vnic_wq_copy *wq)
{
    return wq->ring.desc_avail;
}

static inline unsigned int vnic_wq_copy_desc_in_use(struct vnic_wq_copy *wq)
{
    return wq->ring.desc_count - 1 - wq->ring.desc_avail;
}

static inline void *vnic_wq_copy_next_desc(struct vnic_wq_copy *wq)
{
    struct fcpio_host_req *desc = wq->ring.descs;
    return &desc[wq->to_use_index];
}

static inline void vnic_wq_copy_post(struct vnic_wq_copy *wq)
{

    ((wq->to_use_index + 1) == wq->ring.desc_count) ?
        (wq->to_use_index = 0) : (wq->to_use_index++);
    wq->ring.desc_avail--;

    /* Adding write memory barrier prevents compiler and/or CPU
     * reordering, thus avoiding descriptor posting before
     * descriptor is initialized. Otherwise, hardware can read
     * stale descriptor fields.
     */
    wmb();

    iowrite32(wq->to_use_index, &wq->ctrl->posted_index);
}

static inline void vnic_wq_copy_desc_process(struct vnic_wq_copy *wq, u16 index)
{
    unsigned int cnt;

    if (wq->to_clean_index <= index)
        cnt = (index - wq->to_clean_index) + 1;
    else
        cnt = wq->ring.desc_count - wq->to_clean_index + index + 1;

    wq->to_clean_index = ((index + 1) % wq->ring.desc_count);
    wq->ring.desc_avail += cnt;

}

static inline void vnic_wq_copy_service(struct vnic_wq_copy *wq,
    u16 completed_index,
    void (*q_service)(struct vnic_wq_copy *wq,
    struct fcpio_host_req *wq_desc))
{
    struct fcpio_host_req *wq_desc = wq->ring.descs;
    unsigned int curr_index;

    while (1) {

        if (q_service)
            (*q_service)(wq, &wq_desc[wq->to_clean_index]);

        wq->ring.desc_avail++;

        curr_index = wq->to_clean_index;

        /* increment the to-clean index so that we start
         * with an unprocessed index next time we enter the loop
         */
        ((wq->to_clean_index + 1) == wq->ring.desc_count) ?
            (wq->to_clean_index = 0) : (wq->to_clean_index++);

        if (curr_index == completed_index)
            break;

        /* we have cleaned all the entries */
        if ((completed_index == (u16)-1) &&
            (wq->to_clean_index == wq->to_use_index))
            break;
    }
}

void vnic_wq_copy_enable(struct vnic_wq_copy *wq);
int vnic_wq_copy_disable(struct vnic_wq_copy *wq);
void vnic_wq_copy_free(struct vnic_wq_copy *wq);
int vnic_wq_copy_alloc(struct vnic_dev *vdev, struct vnic_wq_copy *wq,
    unsigned int index, unsigned int desc_count, unsigned int desc_size);
void vnic_wq_copy_init(struct vnic_wq_copy *wq, unsigned int cq_index,
    unsigned int error_interrupt_enable,
    unsigned int error_interrupt_offset);
void vnic_wq_copy_clean(struct vnic_wq_copy *wq,
    void (*q_clean)(struct vnic_wq_copy *wq,
    struct fcpio_host_req *wq_desc));

#endif /* _VNIC_WQ_COPY_H_ */