LXR linux/drivers/scsi/fnic/vnic_wq

   1/*
   2 * Copyright 2008 Cisco Systems, Inc.  All rights reserved.
   3 * Copyright 2007 Nuova Systems, Inc.  All rights reserved.
   4 *
   5 * This program is free software; you may redistribute it and/or modify
   6 * it under the terms of the GNU General Public License as published by
   7 * the Free Software Foundation; version 2 of the License.
   8 *
   9 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  10 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  11 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  12 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  13 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  14 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  15 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  16 * SOFTWARE.
  17 */
  18#ifndef _VNIC_WQ_COPY_H_
  19#define _VNIC_WQ_COPY_H_
  20
  21#include <linux/pci.h>
  22#include "vnic_wq.h"
  23#include "fcpio.h"
  24
  25#define VNIC_WQ_COPY_MAX 1
  26
  27struct vnic_wq_copy {
  28        unsigned int index;
  29        struct vnic_dev *vdev;
  30        struct vnic_wq_ctrl __iomem *ctrl;      /* memory-mapped */
  31        struct vnic_dev_ring ring;
  32        unsigned to_use_index;
  33        unsigned to_clean_index;
  34};
  35
  36static inline unsigned int vnic_wq_copy_desc_avail(struct vnic_wq_copy *wq)
  37{
  38        return wq->ring.desc_avail;
  39}
  40
  41static inline unsigned int vnic_wq_copy_desc_in_use(struct vnic_wq_copy *wq)
  42{
  43        return wq->ring.desc_count - 1 - wq->ring.desc_avail;
  44}
  45
  46static inline void *vnic_wq_copy_next_desc(struct vnic_wq_copy *wq)
  47{
  48        struct fcpio_host_req *desc = wq->ring.descs;
  49        return &desc[wq->to_use_index];
  50}
  51
  52static inline void vnic_wq_copy_post(struct vnic_wq_copy *wq)
  53{
  54
  55        ((wq->to_use_index + 1) == wq->ring.desc_count) ?
  56                (wq->to_use_index = 0) : (wq->to_use_index++);
  57        wq->ring.desc_avail--;
  58
  59        /* Adding write memory barrier prevents compiler and/or CPU
  60         * reordering, thus avoiding descriptor posting before
  61         * descriptor is initialized. Otherwise, hardware can read
  62         * stale descriptor fields.
  63         */
  64        wmb();
  65
  66        iowrite32(wq->to_use_index, &wq->ctrl->posted_index);
  67}
  68
  69static inline void vnic_wq_copy_desc_process(struct vnic_wq_copy *wq, u16 index)
  70{
  71        unsigned int cnt;
  72
  73        if (wq->to_clean_index <= index)
  74                cnt = (index - wq->to_clean_index) + 1;
  75        else
  76                cnt = wq->ring.desc_count - wq->to_clean_index + index + 1;
  77
  78        wq->to_clean_index = ((index + 1) % wq->ring.desc_count);
  79        wq->ring.desc_avail += cnt;
  80
  81}
  82
  83static inline void vnic_wq_copy_service(struct vnic_wq_copy *wq,
  84        u16 completed_index,
  85        void (*q_service)(struct vnic_wq_copy *wq,
  86        struct fcpio_host_req *wq_desc))
  87{
  88        struct fcpio_host_req *wq_desc = wq->ring.descs;
  89        unsigned int curr_index;
  90
  91        while (1) {
  92
  93                if (q_service)
  94                        (*q_service)(wq, &wq_desc[wq->to_clean_index]);
  95
  96                wq->ring.desc_avail++;
  97
  98                curr_index = wq->to_clean_index;
  99
 100                /* increment the to-clean index so that we start
 101                 * with an unprocessed index next time we enter the loop
 102                 */
 103                ((wq->to_clean_index + 1) == wq->ring.desc_count) ?
 104                        (wq->to_clean_index = 0) : (wq->to_clean_index++);
 105
 106                if (curr_index == completed_index)
 107                        break;
 108
 109                /* we have cleaned all the entries */
 110                if ((completed_index == (u16)-1) &&
 111                    (wq->to_clean_index == wq->to_use_index))
 112                        break;
 113        }
 114}
 115
 116void vnic_wq_copy_enable(struct vnic_wq_copy *wq);
 117int vnic_wq_copy_disable(struct vnic_wq_copy *wq);
 118void vnic_wq_copy_free(struct vnic_wq_copy *wq);
 119int vnic_wq_copy_alloc(struct vnic_dev *vdev, struct vnic_wq_copy *wq,
 120        unsigned int index, unsigned int desc_count, unsigned int desc_size);
 121void vnic_wq_copy_init(struct vnic_wq_copy *wq, unsigned int cq_index,
 122        unsigned int error_interrupt_enable,
 123        unsigned int error_interrupt_offset);
 124void vnic_wq_copy_clean(struct vnic_wq_copy *wq,
 125        void (*q_clean)(struct vnic_wq_copy *wq,
 126        struct fcpio_host_req *wq_desc));
 127
 128#endif /* _VNIC_WQ_COPY_H_ */
 129