blob: 5b50bb31f7c6f7fd2a4895afab42c740ff6ded05 [file] [log] [blame]
Joerg Roedelf2f45e52009-01-09 12:19:52 +01001/*
2 * Copyright (C) 2008 Advanced Micro Devices, Inc.
3 *
4 * Author: Joerg Roedel <joerg.roedel@amd.com>
5 *
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.
9 *
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.
14 *
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
18 */
19
20#include <linux/dma-debug.h>
Joerg Roedel30dfa902009-01-09 12:34:49 +010021#include <linux/spinlock.h>
Joerg Roedelf2f45e52009-01-09 12:19:52 +010022#include <linux/types.h>
23#include <linux/list.h>
Joerg Roedel6bf07872009-01-09 12:54:42 +010024#include <linux/slab.h>
Joerg Roedelf2f45e52009-01-09 12:19:52 +010025
Joerg Roedel30dfa902009-01-09 12:34:49 +010026#define HASH_SIZE 1024ULL
27#define HASH_FN_SHIFT 13
28#define HASH_FN_MASK (HASH_SIZE - 1)
29
Joerg Roedelf2f45e52009-01-09 12:19:52 +010030enum {
31 dma_debug_single,
32 dma_debug_page,
33 dma_debug_sg,
34 dma_debug_coherent,
35};
36
37struct dma_debug_entry {
38 struct list_head list;
39 struct device *dev;
40 int type;
41 phys_addr_t paddr;
42 u64 dev_addr;
43 u64 size;
44 int direction;
45 int sg_call_ents;
46 int sg_mapped_ents;
47};
48
Joerg Roedel30dfa902009-01-09 12:34:49 +010049struct hash_bucket {
50 struct list_head list;
51 spinlock_t lock;
52} __cacheline_aligned_in_smp;
53
54/* Hash list to save the allocated dma addresses */
55static struct hash_bucket dma_entry_hash[HASH_SIZE];
Joerg Roedel3b1e79e2009-01-09 12:42:46 +010056/* List of pre-allocated dma_debug_entry's */
57static LIST_HEAD(free_entries);
58/* Lock for the list above */
59static DEFINE_SPINLOCK(free_entries_lock);
60
61/* Global disable flag - will be set in case of an error */
62static bool global_disable __read_mostly;
63
64static u32 num_free_entries;
65static u32 min_free_entries;
Joerg Roedel30dfa902009-01-09 12:34:49 +010066
67/*
68 * Hash related functions
69 *
70 * Every DMA-API request is saved into a struct dma_debug_entry. To
71 * have quick access to these structs they are stored into a hash.
72 */
73static int hash_fn(struct dma_debug_entry *entry)
74{
75 /*
76 * Hash function is based on the dma address.
77 * We use bits 20-27 here as the index into the hash
78 */
79 return (entry->dev_addr >> HASH_FN_SHIFT) & HASH_FN_MASK;
80}
81
82/*
83 * Request exclusive access to a hash bucket for a given dma_debug_entry.
84 */
85static struct hash_bucket *get_hash_bucket(struct dma_debug_entry *entry,
86 unsigned long *flags)
87{
88 int idx = hash_fn(entry);
89 unsigned long __flags;
90
91 spin_lock_irqsave(&dma_entry_hash[idx].lock, __flags);
92 *flags = __flags;
93 return &dma_entry_hash[idx];
94}
95
96/*
97 * Give up exclusive access to the hash bucket
98 */
99static void put_hash_bucket(struct hash_bucket *bucket,
100 unsigned long *flags)
101{
102 unsigned long __flags = *flags;
103
104 spin_unlock_irqrestore(&bucket->lock, __flags);
105}
106
107/*
108 * Search a given entry in the hash bucket list
109 */
110static struct dma_debug_entry *hash_bucket_find(struct hash_bucket *bucket,
111 struct dma_debug_entry *ref)
112{
113 struct dma_debug_entry *entry;
114
115 list_for_each_entry(entry, &bucket->list, list) {
116 if ((entry->dev_addr == ref->dev_addr) &&
117 (entry->dev == ref->dev))
118 return entry;
119 }
120
121 return NULL;
122}
123
124/*
125 * Add an entry to a hash bucket
126 */
127static void hash_bucket_add(struct hash_bucket *bucket,
128 struct dma_debug_entry *entry)
129{
130 list_add_tail(&entry->list, &bucket->list);
131}
132
133/*
134 * Remove entry from a hash bucket list
135 */
136static void hash_bucket_del(struct dma_debug_entry *entry)
137{
138 list_del(&entry->list);
139}
140
141/*
142 * Wrapper function for adding an entry to the hash.
143 * This function takes care of locking itself.
144 */
145static void add_dma_entry(struct dma_debug_entry *entry)
146{
147 struct hash_bucket *bucket;
148 unsigned long flags;
149
150 bucket = get_hash_bucket(entry, &flags);
151 hash_bucket_add(bucket, entry);
152 put_hash_bucket(bucket, &flags);
153}
154
Joerg Roedel3b1e79e2009-01-09 12:42:46 +0100155/* struct dma_entry allocator
156 *
157 * The next two functions implement the allocator for
158 * struct dma_debug_entries.
159 */
160static struct dma_debug_entry *dma_entry_alloc(void)
161{
162 struct dma_debug_entry *entry = NULL;
163 unsigned long flags;
164
165 spin_lock_irqsave(&free_entries_lock, flags);
166
167 if (list_empty(&free_entries)) {
168 printk(KERN_ERR "DMA-API: debugging out of memory "
169 "- disabling\n");
170 global_disable = true;
171 goto out;
172 }
173
174 entry = list_entry(free_entries.next, struct dma_debug_entry, list);
175 list_del(&entry->list);
176 memset(entry, 0, sizeof(*entry));
177
178 num_free_entries -= 1;
179 if (num_free_entries < min_free_entries)
180 min_free_entries = num_free_entries;
181
182out:
183 spin_unlock_irqrestore(&free_entries_lock, flags);
184
185 return entry;
186}
187
188static void dma_entry_free(struct dma_debug_entry *entry)
189{
190 unsigned long flags;
191
192 /*
193 * add to beginning of the list - this way the entries are
194 * more likely cache hot when they are reallocated.
195 */
196 spin_lock_irqsave(&free_entries_lock, flags);
197 list_add(&entry->list, &free_entries);
198 num_free_entries += 1;
199 spin_unlock_irqrestore(&free_entries_lock, flags);
200}
201
Joerg Roedel6bf07872009-01-09 12:54:42 +0100202/*
203 * DMA-API debugging init code
204 *
205 * The init code does two things:
206 * 1. Initialize core data structures
207 * 2. Preallocate a given number of dma_debug_entry structs
208 */
209
210static int prealloc_memory(u32 num_entries)
211{
212 struct dma_debug_entry *entry, *next_entry;
213 int i;
214
215 for (i = 0; i < num_entries; ++i) {
216 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
217 if (!entry)
218 goto out_err;
219
220 list_add_tail(&entry->list, &free_entries);
221 }
222
223 num_free_entries = num_entries;
224 min_free_entries = num_entries;
225
226 printk(KERN_INFO "DMA-API: preallocated %d debug entries\n",
227 num_entries);
228
229 return 0;
230
231out_err:
232
233 list_for_each_entry_safe(entry, next_entry, &free_entries, list) {
234 list_del(&entry->list);
235 kfree(entry);
236 }
237
238 return -ENOMEM;
239}
240
241/*
242 * Let the architectures decide how many entries should be preallocated.
243 */
244void dma_debug_init(u32 num_entries)
245{
246 int i;
247
248 if (global_disable)
249 return;
250
251 for (i = 0; i < HASH_SIZE; ++i) {
252 INIT_LIST_HEAD(&dma_entry_hash[i].list);
253 dma_entry_hash[i].lock = SPIN_LOCK_UNLOCKED;
254 }
255
256 if (prealloc_memory(num_entries) != 0) {
257 printk(KERN_ERR "DMA-API: debugging out of memory error "
258 "- disabled\n");
259 global_disable = true;
260
261 return;
262 }
263
264 printk(KERN_INFO "DMA-API: debugging enabled by kernel config\n");
265}
266