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
 52int 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 = bitmap_zalloc(num, 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
 76void pvrdma_uar_table_cleanup(struct pvrdma_dev *dev)
 77{
 78	struct pvrdma_id_table *tbl = &dev->uar_table.tbl;
 79
 80	bitmap_free(tbl->table);
 81}
 82
 83int 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
115void 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}