drivers/scsi/fnic/vnic_wq_copy.h

   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
  27 struct 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
  36 static inline unsigned int vnic_wq_copy_desc_avail(struct vnic_wq_copy *wq)
  37 {
  38         return wq->ring.desc_avail;
  39 }
  40
  41 static 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
  46 static 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
  52 static 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
  69 static 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
  83 static 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
 116 void vnic_wq_copy_enable(struct vnic_wq_copy *wq);
 117 int vnic_wq_copy_disable(struct vnic_wq_copy *wq);
 118 void vnic_wq_copy_free(struct vnic_wq_copy *wq);
 119 int 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);
 121 void 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);
 124 void 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_ */