2 * Copyright (C) 2008 Advanced Micro Devices, Inc.
4 * Author: Joerg Roedel <joerg.roedel@amd.com>
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 as published
8 * by the Free Software Foundation.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 #include <linux/dma-debug.h>
21 #include <linux/spinlock.h>
22 #include <linux/types.h>
23 #include <linux/list.h>
25 #define HASH_SIZE 1024ULL
26 #define HASH_FN_SHIFT 13
27 #define HASH_FN_MASK (HASH_SIZE - 1)
36 struct dma_debug_entry
{
37 struct list_head list
;
49 struct list_head list
;
51 } __cacheline_aligned_in_smp
;
53 /* Hash list to save the allocated dma addresses */
54 static struct hash_bucket dma_entry_hash
[HASH_SIZE
];
57 * Hash related functions
59 * Every DMA-API request is saved into a struct dma_debug_entry. To
60 * have quick access to these structs they are stored into a hash.
62 static int hash_fn(struct dma_debug_entry
*entry
)
65 * Hash function is based on the dma address.
66 * We use bits 20-27 here as the index into the hash
68 return (entry
->dev_addr
>> HASH_FN_SHIFT
) & HASH_FN_MASK
;
72 * Request exclusive access to a hash bucket for a given dma_debug_entry.
74 static struct hash_bucket
*get_hash_bucket(struct dma_debug_entry
*entry
,
77 int idx
= hash_fn(entry
);
78 unsigned long __flags
;
80 spin_lock_irqsave(&dma_entry_hash
[idx
].lock
, __flags
);
82 return &dma_entry_hash
[idx
];
86 * Give up exclusive access to the hash bucket
88 static void put_hash_bucket(struct hash_bucket
*bucket
,
91 unsigned long __flags
= *flags
;
93 spin_unlock_irqrestore(&bucket
->lock
, __flags
);
97 * Search a given entry in the hash bucket list
99 static struct dma_debug_entry
*hash_bucket_find(struct hash_bucket
*bucket
,
100 struct dma_debug_entry
*ref
)
102 struct dma_debug_entry
*entry
;
104 list_for_each_entry(entry
, &bucket
->list
, list
) {
105 if ((entry
->dev_addr
== ref
->dev_addr
) &&
106 (entry
->dev
== ref
->dev
))
114 * Add an entry to a hash bucket
116 static void hash_bucket_add(struct hash_bucket
*bucket
,
117 struct dma_debug_entry
*entry
)
119 list_add_tail(&entry
->list
, &bucket
->list
);
123 * Remove entry from a hash bucket list
125 static void hash_bucket_del(struct dma_debug_entry
*entry
)
127 list_del(&entry
->list
);
131 * Wrapper function for adding an entry to the hash.
132 * This function takes care of locking itself.
134 static void add_dma_entry(struct dma_debug_entry
*entry
)
136 struct hash_bucket
*bucket
;
139 bucket
= get_hash_bucket(entry
, &flags
);
140 hash_bucket_add(bucket
, entry
);
141 put_hash_bucket(bucket
, &flags
);