hw/vmw_pvrdma/pvrdma_doorbell.c

0001 /*
0002  * Copyright (c) 2012-2016 VMware, Inc.  All rights reserved.
0003  *
0004  * This program is free software; you can redistribute it and/or
0005  * modify it under the terms of EITHER the GNU General Public License
0006  * version 2 as published by the Free Software Foundation or the BSD
0007  * 2-Clause License. This program is distributed in the hope that it
0008  * will be useful, but WITHOUT ANY WARRANTY; WITHOUT EVEN THE IMPLIED
0009  * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
0010  * See the GNU General Public License version 2 for more details at
0011  * http://www.gnu.org/licenses/old-licenses/gpl-2.0.en.html.
0012  *
0013  * You should have received a copy of the GNU General Public License
0014  * along with this program available in the file COPYING in the main
0015  * directory of this source tree.
0016  *
0017  * The BSD 2-Clause License
0018  *
0019  *     Redistribution and use in source and binary forms, with or
0020  *     without modification, are permitted provided that the following
0021  *     conditions are met:
0022  *
0023  *      - Redistributions of source code must retain the above
0024  *        copyright notice, this list of conditions and the following
0025  *        disclaimer.
0026  *
0027  *      - Redistributions in binary form must reproduce the above
0028  *        copyright notice, this list of conditions and the following
0029  *        disclaimer in the documentation and/or other materials
0030  *        provided with the distribution.
0031  *
0032  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
0033  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
0034  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
0035  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
0036  * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
0037  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
0038  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
0039  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
0040  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
0041  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
0042  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
0043  * OF THE POSSIBILITY OF SUCH DAMAGE.
0044  */
0045
0046 #include <linux/bitmap.h>
0047 #include <linux/errno.h>
0048 #include <linux/slab.h>
0049
0050 #include "pvrdma.h"
0051
0052 int pvrdma_uar_table_init(struct pvrdma_dev *dev)
0053 {
0054     u32 num = dev->dsr->caps.max_uar;
0055     u32 mask = num - 1;
0056     struct pvrdma_id_table *tbl = &dev->uar_table.tbl;
0057
0058     if (!is_power_of_2(num))
0059         return -EINVAL;
0060
0061     tbl->last = 0;
0062     tbl->top = 0;
0063     tbl->max = num;
0064     tbl->mask = mask;
0065     spin_lock_init(&tbl->lock);
0066     tbl->table = bitmap_zalloc(num, GFP_KERNEL);
0067     if (!tbl->table)
0068         return -ENOMEM;
0069
0070     /* 0th UAR is taken by the device. */
0071     __set_bit(0, tbl->table);
0072
0073     return 0;
0074 }
0075
0076 void pvrdma_uar_table_cleanup(struct pvrdma_dev *dev)
0077 {
0078     struct pvrdma_id_table *tbl = &dev->uar_table.tbl;
0079
0080     bitmap_free(tbl->table);
0081 }
0082
0083 int pvrdma_uar_alloc(struct pvrdma_dev *dev, struct pvrdma_uar_map *uar)
0084 {
0085     struct pvrdma_id_table *tbl;
0086     unsigned long flags;
0087     u32 obj;
0088
0089     tbl = &dev->uar_table.tbl;
0090
0091     spin_lock_irqsave(&tbl->lock, flags);
0092     obj = find_next_zero_bit(tbl->table, tbl->max, tbl->last);
0093     if (obj >= tbl->max) {
0094         tbl->top = (tbl->top + tbl->max) & tbl->mask;
0095         obj = find_first_zero_bit(tbl->table, tbl->max);
0096     }
0097
0098     if (obj >= tbl->max) {
0099         spin_unlock_irqrestore(&tbl->lock, flags);
0100         return -ENOMEM;
0101     }
0102
0103     __set_bit(obj, tbl->table);
0104     obj |= tbl->top;
0105
0106     spin_unlock_irqrestore(&tbl->lock, flags);
0107
0108     uar->index = obj;
0109     uar->pfn = (pci_resource_start(dev->pdev, PVRDMA_PCI_RESOURCE_UAR) >>
0110             PAGE_SHIFT) + uar->index;
0111
0112     return 0;
0113 }
0114
0115 void pvrdma_uar_free(struct pvrdma_dev *dev, struct pvrdma_uar_map *uar)
0116 {
0117     struct pvrdma_id_table *tbl = &dev->uar_table.tbl;
0118     unsigned long flags;
0119     u32 obj;
0120
0121     obj = uar->index & (tbl->max - 1);
0122     spin_lock_irqsave(&tbl->lock, flags);
0123     __clear_bit(obj, tbl->table);
0124     tbl->last = min(tbl->last, obj);
0125     tbl->top = (tbl->top + tbl->max) & tbl->mask;
0126     spin_unlock_irqrestore(&tbl->lock, flags);
0127 }