drivers/scsi/fnic/vnic_wq_copy.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  * Copyright 2008 Cisco Systems, Inc.  All rights reserved.
   4  * Copyright 2007 Nuova Systems, Inc.  All rights reserved.
   5  */
   6 #ifndef _VNIC_WQ_COPY_H_
   7 #define _VNIC_WQ_COPY_H_
   8
   9 #include <linux/pci.h>
  10 #include "vnic_wq.h"
  11 #include "fcpio.h"
  12
  13 #define VNIC_WQ_COPY_MAX 1
  14
  15 struct vnic_wq_copy {
  16         unsigned int index;
  17         struct vnic_dev *vdev;
  18         struct vnic_wq_ctrl __iomem *ctrl;      /* memory-mapped */
  19         struct vnic_dev_ring ring;
  20         unsigned to_use_index;
  21         unsigned to_clean_index;
  22 };
  23
  24 static inline unsigned int vnic_wq_copy_desc_avail(struct vnic_wq_copy *wq)
  25 {
  26         return wq->ring.desc_avail;
  27 }
  28
  29 static inline unsigned int vnic_wq_copy_desc_in_use(struct vnic_wq_copy *wq)
  30 {
  31         return wq->ring.desc_count - 1 - wq->ring.desc_avail;
  32 }
  33
  34 static inline void *vnic_wq_copy_next_desc(struct vnic_wq_copy *wq)
  35 {
  36         struct fcpio_host_req *desc = wq->ring.descs;
  37         return &desc[wq->to_use_index];
  38 }
  39
  40 static inline void vnic_wq_copy_post(struct vnic_wq_copy *wq)
  41 {
  42
  43         ((wq->to_use_index + 1) == wq->ring.desc_count) ?
  44                 (wq->to_use_index = 0) : (wq->to_use_index++);
  45         wq->ring.desc_avail--;
  46
  47         /* Adding write memory barrier prevents compiler and/or CPU
  48          * reordering, thus avoiding descriptor posting before
  49          * descriptor is initialized. Otherwise, hardware can read
  50          * stale descriptor fields.
  51          */
  52         wmb();
  53
  54         iowrite32(wq->to_use_index, &wq->ctrl->posted_index);
  55 }
  56
  57 static inline void vnic_wq_copy_desc_process(struct vnic_wq_copy *wq, u16 index)
  58 {
  59         unsigned int cnt;
  60
  61         if (wq->to_clean_index <= index)
  62                 cnt = (index - wq->to_clean_index) + 1;
  63         else
  64                 cnt = wq->ring.desc_count - wq->to_clean_index + index + 1;
  65
  66         wq->to_clean_index = ((index + 1) % wq->ring.desc_count);
  67         wq->ring.desc_avail += cnt;
  68
  69 }
  70
  71 static inline void vnic_wq_copy_service(struct vnic_wq_copy *wq,
  72         u16 completed_index,
  73         void (*q_service)(struct vnic_wq_copy *wq,
  74         struct fcpio_host_req *wq_desc))
  75 {
  76         struct fcpio_host_req *wq_desc = wq->ring.descs;
  77         unsigned int curr_index;
  78
  79         while (1) {
  80
  81                 if (q_service)
  82                         (*q_service)(wq, &wq_desc[wq->to_clean_index]);
  83
  84                 wq->ring.desc_avail++;
  85
  86                 curr_index = wq->to_clean_index;
  87
  88                 /* increment the to-clean index so that we start
  89                  * with an unprocessed index next time we enter the loop
  90                  */
  91                 ((wq->to_clean_index + 1) == wq->ring.desc_count) ?
  92                         (wq->to_clean_index = 0) : (wq->to_clean_index++);
  93
  94                 if (curr_index == completed_index)
  95                         break;
  96
  97                 /* we have cleaned all the entries */
  98                 if ((completed_index == (u16)-1) &&
  99                     (wq->to_clean_index == wq->to_use_index))
 100                         break;
 101         }
 102 }
 103
 104 void vnic_wq_copy_enable(struct vnic_wq_copy *wq);
 105 int vnic_wq_copy_disable(struct vnic_wq_copy *wq);
 106 void vnic_wq_copy_free(struct vnic_wq_copy *wq);
 107 int vnic_wq_copy_alloc(struct vnic_dev *vdev, struct vnic_wq_copy *wq,
 108         unsigned int index, unsigned int desc_count, unsigned int desc_size);
 109 void vnic_wq_copy_init(struct vnic_wq_copy *wq, unsigned int cq_index,
 110         unsigned int error_interrupt_enable,
 111         unsigned int error_interrupt_offset);
 112 void vnic_wq_copy_clean(struct vnic_wq_copy *wq,
 113         void (*q_clean)(struct vnic_wq_copy *wq,
 114         struct fcpio_host_req *wq_desc));
 115
 116 #endif /* _VNIC_WQ_COPY_H_ */