drivers/infiniband/hw/vmw_pvrdma/pvrdma_doorbell.c

   1 /*
   2  * Copyright (c) 2012-2016 VMware, Inc.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of EITHER the GNU General Public License
   6  * version 2 as published by the Free Software Foundation or the BSD
   7  * 2-Clause License. This program is distributed in the hope that it
   8  * will be useful, but WITHOUT ANY WARRANTY; WITHOUT EVEN THE IMPLIED
   9  * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
  10  * See the GNU General Public License version 2 for more details at
  11  * http://www.gnu.org/licenses/old-licenses/gpl-2.0.en.html.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this program available in the file COPYING in the main
  15  * directory of this source tree.
  16  *
  17  * The BSD 2-Clause License
  18  *
  19  *     Redistribution and use in source and binary forms, with or
  20  *     without modification, are permitted provided that the following
  21  *     conditions are met:
  22  *
  23  *      - Redistributions of source code must retain the above
  24  *        copyright notice, this list of conditions and the following
  25  *        disclaimer.
  26  *
  27  *      - Redistributions in binary form must reproduce the above
  28  *        copyright notice, this list of conditions and the following
  29  *        disclaimer in the documentation and/or other materials
  30  *        provided with the distribution.
  31  *
  32  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  33  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  34  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  35  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  36  * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
  37  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  38  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  39  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  40  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  41  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  42  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
  43  * OF THE POSSIBILITY OF SUCH DAMAGE.
  44  */
  45
  46 #include <linux/bitmap.h>
  47 #include <linux/errno.h>
  48 #include <linux/slab.h>
  49
  50 #include "pvrdma.h"
  51
  52 int pvrdma_uar_table_init(struct pvrdma_dev *dev)
  53 {
  54         u32 num = dev->dsr->caps.max_uar;
  55         u32 mask = num - 1;
  56         struct pvrdma_id_table *tbl = &dev->uar_table.tbl;
  57
  58         if (!is_power_of_2(num))
  59                 return -EINVAL;
  60
  61         tbl->last = 0;
  62         tbl->top = 0;
  63         tbl->max = num;
  64         tbl->mask = mask;
  65         spin_lock_init(&tbl->lock);
  66         tbl->table = kcalloc(BITS_TO_LONGS(num), sizeof(long), GFP_KERNEL);
  67         if (!tbl->table)
  68                 return -ENOMEM;
  69
  70         /* 0th UAR is taken by the device. */
  71         set_bit(0, tbl->table);
  72
  73         return 0;
  74 }
  75
  76 void pvrdma_uar_table_cleanup(struct pvrdma_dev *dev)
  77 {
  78         struct pvrdma_id_table *tbl = &dev->uar_table.tbl;
  79
  80         kfree(tbl->table);
  81 }
  82
  83 int pvrdma_uar_alloc(struct pvrdma_dev *dev, struct pvrdma_uar_map *uar)
  84 {
  85         struct pvrdma_id_table *tbl;
  86         unsigned long flags;
  87         u32 obj;
  88
  89         tbl = &dev->uar_table.tbl;
  90
  91         spin_lock_irqsave(&tbl->lock, flags);
  92         obj = find_next_zero_bit(tbl->table, tbl->max, tbl->last);
  93         if (obj >= tbl->max) {
  94                 tbl->top = (tbl->top + tbl->max) & tbl->mask;
  95                 obj = find_first_zero_bit(tbl->table, tbl->max);
  96         }
  97
  98         if (obj >= tbl->max) {
  99                 spin_unlock_irqrestore(&tbl->lock, flags);
 100                 return -ENOMEM;
 101         }
 102
 103         set_bit(obj, tbl->table);
 104         obj |= tbl->top;
 105
 106         spin_unlock_irqrestore(&tbl->lock, flags);
 107
 108         uar->index = obj;
 109         uar->pfn = (pci_resource_start(dev->pdev, PVRDMA_PCI_RESOURCE_UAR) >>
 110                     PAGE_SHIFT) + uar->index;
 111
 112         return 0;
 113 }
 114
 115 void pvrdma_uar_free(struct pvrdma_dev *dev, struct pvrdma_uar_map *uar)
 116 {
 117         struct pvrdma_id_table *tbl = &dev->uar_table.tbl;
 118         unsigned long flags;
 119         u32 obj;
 120
 121         obj = uar->index & (tbl->max - 1);
 122         spin_lock_irqsave(&tbl->lock, flags);
 123         clear_bit(obj, tbl->table);
 124         tbl->last = min(tbl->last, obj);
 125         tbl->top = (tbl->top + tbl->max) & tbl->mask;
 126         spin_unlock_irqrestore(&tbl->lock, flags);
 127 }