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f2f45e5f JR |
1 | /* |
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> | |
30dfa90c | 21 | #include <linux/spinlock.h> |
f2f45e5f JR |
22 | #include <linux/types.h> |
23 | #include <linux/list.h> | |
6bf07871 | 24 | #include <linux/slab.h> |
f2f45e5f | 25 | |
30dfa90c JR |
26 | #define HASH_SIZE 1024ULL |
27 | #define HASH_FN_SHIFT 13 | |
28 | #define HASH_FN_MASK (HASH_SIZE - 1) | |
29 | ||
f2f45e5f JR |
30 | enum { |
31 | dma_debug_single, | |
32 | dma_debug_page, | |
33 | dma_debug_sg, | |
34 | dma_debug_coherent, | |
35 | }; | |
36 | ||
37 | struct 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 | ||
30dfa90c JR |
49 | struct 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 */ | |
55 | static struct hash_bucket dma_entry_hash[HASH_SIZE]; | |
3b1e79ed JR |
56 | /* List of pre-allocated dma_debug_entry's */ |
57 | static LIST_HEAD(free_entries); | |
58 | /* Lock for the list above */ | |
59 | static DEFINE_SPINLOCK(free_entries_lock); | |
60 | ||
61 | /* Global disable flag - will be set in case of an error */ | |
62 | static bool global_disable __read_mostly; | |
63 | ||
64 | static u32 num_free_entries; | |
65 | static u32 min_free_entries; | |
30dfa90c JR |
66 | |
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 | */ | |
73 | static 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 | */ | |
85 | static 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 | */ | |
99 | static 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 | */ | |
110 | static 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 | */ | |
127 | static 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 | */ | |
136 | static 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 | */ | |
145 | static 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 | ||
3b1e79ed JR |
155 | /* struct dma_entry allocator |
156 | * | |
157 | * The next two functions implement the allocator for | |
158 | * struct dma_debug_entries. | |
159 | */ | |
160 | static 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 | ||
182 | out: | |
183 | spin_unlock_irqrestore(&free_entries_lock, flags); | |
184 | ||
185 | return entry; | |
186 | } | |
187 | ||
188 | static 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 | ||
6bf07871 JR |
202 | /* |
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 | ||
210 | static 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 | ||
231 | out_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 | */ | |
244 | void 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 |