Joerg Roedel | f2f45e5 | 2009-01-09 12:19:52 +0100 | [diff] [blame] | 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> |
Joerg Roedel | 30dfa90 | 2009-01-09 12:34:49 +0100 | [diff] [blame] | 21 | #include <linux/spinlock.h> |
Joerg Roedel | 788dcfa | 2009-01-09 13:13:27 +0100 | [diff] [blame^] | 22 | #include <linux/debugfs.h> |
Joerg Roedel | f2f45e5 | 2009-01-09 12:19:52 +0100 | [diff] [blame] | 23 | #include <linux/types.h> |
| 24 | #include <linux/list.h> |
Joerg Roedel | 6bf0787 | 2009-01-09 12:54:42 +0100 | [diff] [blame] | 25 | #include <linux/slab.h> |
Joerg Roedel | f2f45e5 | 2009-01-09 12:19:52 +0100 | [diff] [blame] | 26 | |
Joerg Roedel | 30dfa90 | 2009-01-09 12:34:49 +0100 | [diff] [blame] | 27 | #define HASH_SIZE 1024ULL |
| 28 | #define HASH_FN_SHIFT 13 |
| 29 | #define HASH_FN_MASK (HASH_SIZE - 1) |
| 30 | |
Joerg Roedel | f2f45e5 | 2009-01-09 12:19:52 +0100 | [diff] [blame] | 31 | enum { |
| 32 | dma_debug_single, |
| 33 | dma_debug_page, |
| 34 | dma_debug_sg, |
| 35 | dma_debug_coherent, |
| 36 | }; |
| 37 | |
| 38 | struct dma_debug_entry { |
| 39 | struct list_head list; |
| 40 | struct device *dev; |
| 41 | int type; |
| 42 | phys_addr_t paddr; |
| 43 | u64 dev_addr; |
| 44 | u64 size; |
| 45 | int direction; |
| 46 | int sg_call_ents; |
| 47 | int sg_mapped_ents; |
| 48 | }; |
| 49 | |
Joerg Roedel | 30dfa90 | 2009-01-09 12:34:49 +0100 | [diff] [blame] | 50 | struct hash_bucket { |
| 51 | struct list_head list; |
| 52 | spinlock_t lock; |
| 53 | } __cacheline_aligned_in_smp; |
| 54 | |
| 55 | /* Hash list to save the allocated dma addresses */ |
| 56 | static struct hash_bucket dma_entry_hash[HASH_SIZE]; |
Joerg Roedel | 3b1e79e | 2009-01-09 12:42:46 +0100 | [diff] [blame] | 57 | /* List of pre-allocated dma_debug_entry's */ |
| 58 | static LIST_HEAD(free_entries); |
| 59 | /* Lock for the list above */ |
| 60 | static DEFINE_SPINLOCK(free_entries_lock); |
| 61 | |
| 62 | /* Global disable flag - will be set in case of an error */ |
| 63 | static bool global_disable __read_mostly; |
| 64 | |
Joerg Roedel | 788dcfa | 2009-01-09 13:13:27 +0100 | [diff] [blame^] | 65 | /* Global error count */ |
| 66 | static u32 error_count; |
| 67 | |
| 68 | /* Global error show enable*/ |
| 69 | static u32 show_all_errors __read_mostly; |
| 70 | /* Number of errors to show */ |
| 71 | static u32 show_num_errors = 1; |
| 72 | |
Joerg Roedel | 3b1e79e | 2009-01-09 12:42:46 +0100 | [diff] [blame] | 73 | static u32 num_free_entries; |
| 74 | static u32 min_free_entries; |
Joerg Roedel | 30dfa90 | 2009-01-09 12:34:49 +0100 | [diff] [blame] | 75 | |
Joerg Roedel | 59d3daa | 2009-01-09 13:01:56 +0100 | [diff] [blame] | 76 | /* number of preallocated entries requested by kernel cmdline */ |
| 77 | static u32 req_entries; |
| 78 | |
Joerg Roedel | 788dcfa | 2009-01-09 13:13:27 +0100 | [diff] [blame^] | 79 | /* debugfs dentry's for the stuff above */ |
| 80 | static struct dentry *dma_debug_dent __read_mostly; |
| 81 | static struct dentry *global_disable_dent __read_mostly; |
| 82 | static struct dentry *error_count_dent __read_mostly; |
| 83 | static struct dentry *show_all_errors_dent __read_mostly; |
| 84 | static struct dentry *show_num_errors_dent __read_mostly; |
| 85 | static struct dentry *num_free_entries_dent __read_mostly; |
| 86 | static struct dentry *min_free_entries_dent __read_mostly; |
| 87 | |
Joerg Roedel | 30dfa90 | 2009-01-09 12:34:49 +0100 | [diff] [blame] | 88 | /* |
| 89 | * Hash related functions |
| 90 | * |
| 91 | * Every DMA-API request is saved into a struct dma_debug_entry. To |
| 92 | * have quick access to these structs they are stored into a hash. |
| 93 | */ |
| 94 | static int hash_fn(struct dma_debug_entry *entry) |
| 95 | { |
| 96 | /* |
| 97 | * Hash function is based on the dma address. |
| 98 | * We use bits 20-27 here as the index into the hash |
| 99 | */ |
| 100 | return (entry->dev_addr >> HASH_FN_SHIFT) & HASH_FN_MASK; |
| 101 | } |
| 102 | |
| 103 | /* |
| 104 | * Request exclusive access to a hash bucket for a given dma_debug_entry. |
| 105 | */ |
| 106 | static struct hash_bucket *get_hash_bucket(struct dma_debug_entry *entry, |
| 107 | unsigned long *flags) |
| 108 | { |
| 109 | int idx = hash_fn(entry); |
| 110 | unsigned long __flags; |
| 111 | |
| 112 | spin_lock_irqsave(&dma_entry_hash[idx].lock, __flags); |
| 113 | *flags = __flags; |
| 114 | return &dma_entry_hash[idx]; |
| 115 | } |
| 116 | |
| 117 | /* |
| 118 | * Give up exclusive access to the hash bucket |
| 119 | */ |
| 120 | static void put_hash_bucket(struct hash_bucket *bucket, |
| 121 | unsigned long *flags) |
| 122 | { |
| 123 | unsigned long __flags = *flags; |
| 124 | |
| 125 | spin_unlock_irqrestore(&bucket->lock, __flags); |
| 126 | } |
| 127 | |
| 128 | /* |
| 129 | * Search a given entry in the hash bucket list |
| 130 | */ |
| 131 | static struct dma_debug_entry *hash_bucket_find(struct hash_bucket *bucket, |
| 132 | struct dma_debug_entry *ref) |
| 133 | { |
| 134 | struct dma_debug_entry *entry; |
| 135 | |
| 136 | list_for_each_entry(entry, &bucket->list, list) { |
| 137 | if ((entry->dev_addr == ref->dev_addr) && |
| 138 | (entry->dev == ref->dev)) |
| 139 | return entry; |
| 140 | } |
| 141 | |
| 142 | return NULL; |
| 143 | } |
| 144 | |
| 145 | /* |
| 146 | * Add an entry to a hash bucket |
| 147 | */ |
| 148 | static void hash_bucket_add(struct hash_bucket *bucket, |
| 149 | struct dma_debug_entry *entry) |
| 150 | { |
| 151 | list_add_tail(&entry->list, &bucket->list); |
| 152 | } |
| 153 | |
| 154 | /* |
| 155 | * Remove entry from a hash bucket list |
| 156 | */ |
| 157 | static void hash_bucket_del(struct dma_debug_entry *entry) |
| 158 | { |
| 159 | list_del(&entry->list); |
| 160 | } |
| 161 | |
| 162 | /* |
| 163 | * Wrapper function for adding an entry to the hash. |
| 164 | * This function takes care of locking itself. |
| 165 | */ |
| 166 | static void add_dma_entry(struct dma_debug_entry *entry) |
| 167 | { |
| 168 | struct hash_bucket *bucket; |
| 169 | unsigned long flags; |
| 170 | |
| 171 | bucket = get_hash_bucket(entry, &flags); |
| 172 | hash_bucket_add(bucket, entry); |
| 173 | put_hash_bucket(bucket, &flags); |
| 174 | } |
| 175 | |
Joerg Roedel | 3b1e79e | 2009-01-09 12:42:46 +0100 | [diff] [blame] | 176 | /* struct dma_entry allocator |
| 177 | * |
| 178 | * The next two functions implement the allocator for |
| 179 | * struct dma_debug_entries. |
| 180 | */ |
| 181 | static struct dma_debug_entry *dma_entry_alloc(void) |
| 182 | { |
| 183 | struct dma_debug_entry *entry = NULL; |
| 184 | unsigned long flags; |
| 185 | |
| 186 | spin_lock_irqsave(&free_entries_lock, flags); |
| 187 | |
| 188 | if (list_empty(&free_entries)) { |
| 189 | printk(KERN_ERR "DMA-API: debugging out of memory " |
| 190 | "- disabling\n"); |
| 191 | global_disable = true; |
| 192 | goto out; |
| 193 | } |
| 194 | |
| 195 | entry = list_entry(free_entries.next, struct dma_debug_entry, list); |
| 196 | list_del(&entry->list); |
| 197 | memset(entry, 0, sizeof(*entry)); |
| 198 | |
| 199 | num_free_entries -= 1; |
| 200 | if (num_free_entries < min_free_entries) |
| 201 | min_free_entries = num_free_entries; |
| 202 | |
| 203 | out: |
| 204 | spin_unlock_irqrestore(&free_entries_lock, flags); |
| 205 | |
| 206 | return entry; |
| 207 | } |
| 208 | |
| 209 | static void dma_entry_free(struct dma_debug_entry *entry) |
| 210 | { |
| 211 | unsigned long flags; |
| 212 | |
| 213 | /* |
| 214 | * add to beginning of the list - this way the entries are |
| 215 | * more likely cache hot when they are reallocated. |
| 216 | */ |
| 217 | spin_lock_irqsave(&free_entries_lock, flags); |
| 218 | list_add(&entry->list, &free_entries); |
| 219 | num_free_entries += 1; |
| 220 | spin_unlock_irqrestore(&free_entries_lock, flags); |
| 221 | } |
| 222 | |
Joerg Roedel | 6bf0787 | 2009-01-09 12:54:42 +0100 | [diff] [blame] | 223 | /* |
| 224 | * DMA-API debugging init code |
| 225 | * |
| 226 | * The init code does two things: |
| 227 | * 1. Initialize core data structures |
| 228 | * 2. Preallocate a given number of dma_debug_entry structs |
| 229 | */ |
| 230 | |
| 231 | static int prealloc_memory(u32 num_entries) |
| 232 | { |
| 233 | struct dma_debug_entry *entry, *next_entry; |
| 234 | int i; |
| 235 | |
| 236 | for (i = 0; i < num_entries; ++i) { |
| 237 | entry = kzalloc(sizeof(*entry), GFP_KERNEL); |
| 238 | if (!entry) |
| 239 | goto out_err; |
| 240 | |
| 241 | list_add_tail(&entry->list, &free_entries); |
| 242 | } |
| 243 | |
| 244 | num_free_entries = num_entries; |
| 245 | min_free_entries = num_entries; |
| 246 | |
| 247 | printk(KERN_INFO "DMA-API: preallocated %d debug entries\n", |
| 248 | num_entries); |
| 249 | |
| 250 | return 0; |
| 251 | |
| 252 | out_err: |
| 253 | |
| 254 | list_for_each_entry_safe(entry, next_entry, &free_entries, list) { |
| 255 | list_del(&entry->list); |
| 256 | kfree(entry); |
| 257 | } |
| 258 | |
| 259 | return -ENOMEM; |
| 260 | } |
| 261 | |
Joerg Roedel | 788dcfa | 2009-01-09 13:13:27 +0100 | [diff] [blame^] | 262 | static int dma_debug_fs_init(void) |
| 263 | { |
| 264 | dma_debug_dent = debugfs_create_dir("dma-api", NULL); |
| 265 | if (!dma_debug_dent) { |
| 266 | printk(KERN_ERR "DMA-API: can not create debugfs directory\n"); |
| 267 | return -ENOMEM; |
| 268 | } |
| 269 | |
| 270 | global_disable_dent = debugfs_create_bool("disabled", 0444, |
| 271 | dma_debug_dent, |
| 272 | (u32 *)&global_disable); |
| 273 | if (!global_disable_dent) |
| 274 | goto out_err; |
| 275 | |
| 276 | error_count_dent = debugfs_create_u32("error_count", 0444, |
| 277 | dma_debug_dent, &error_count); |
| 278 | if (!error_count_dent) |
| 279 | goto out_err; |
| 280 | |
| 281 | show_all_errors_dent = debugfs_create_u32("all_errors", 0644, |
| 282 | dma_debug_dent, |
| 283 | &show_all_errors); |
| 284 | if (!show_all_errors_dent) |
| 285 | goto out_err; |
| 286 | |
| 287 | show_num_errors_dent = debugfs_create_u32("num_errors", 0644, |
| 288 | dma_debug_dent, |
| 289 | &show_num_errors); |
| 290 | if (!show_num_errors_dent) |
| 291 | goto out_err; |
| 292 | |
| 293 | num_free_entries_dent = debugfs_create_u32("num_free_entries", 0444, |
| 294 | dma_debug_dent, |
| 295 | &num_free_entries); |
| 296 | if (!num_free_entries_dent) |
| 297 | goto out_err; |
| 298 | |
| 299 | min_free_entries_dent = debugfs_create_u32("min_free_entries", 0444, |
| 300 | dma_debug_dent, |
| 301 | &min_free_entries); |
| 302 | if (!min_free_entries_dent) |
| 303 | goto out_err; |
| 304 | |
| 305 | return 0; |
| 306 | |
| 307 | out_err: |
| 308 | debugfs_remove_recursive(dma_debug_dent); |
| 309 | |
| 310 | return -ENOMEM; |
| 311 | } |
| 312 | |
| 313 | |
Joerg Roedel | 6bf0787 | 2009-01-09 12:54:42 +0100 | [diff] [blame] | 314 | /* |
| 315 | * Let the architectures decide how many entries should be preallocated. |
| 316 | */ |
| 317 | void dma_debug_init(u32 num_entries) |
| 318 | { |
| 319 | int i; |
| 320 | |
| 321 | if (global_disable) |
| 322 | return; |
| 323 | |
| 324 | for (i = 0; i < HASH_SIZE; ++i) { |
| 325 | INIT_LIST_HEAD(&dma_entry_hash[i].list); |
| 326 | dma_entry_hash[i].lock = SPIN_LOCK_UNLOCKED; |
| 327 | } |
| 328 | |
Joerg Roedel | 788dcfa | 2009-01-09 13:13:27 +0100 | [diff] [blame^] | 329 | if (dma_debug_fs_init() != 0) { |
| 330 | printk(KERN_ERR "DMA-API: error creating debugfs entries " |
| 331 | "- disabling\n"); |
| 332 | global_disable = true; |
| 333 | |
| 334 | return; |
| 335 | } |
| 336 | |
Joerg Roedel | 59d3daa | 2009-01-09 13:01:56 +0100 | [diff] [blame] | 337 | if (req_entries) |
| 338 | num_entries = req_entries; |
| 339 | |
Joerg Roedel | 6bf0787 | 2009-01-09 12:54:42 +0100 | [diff] [blame] | 340 | if (prealloc_memory(num_entries) != 0) { |
| 341 | printk(KERN_ERR "DMA-API: debugging out of memory error " |
| 342 | "- disabled\n"); |
| 343 | global_disable = true; |
| 344 | |
| 345 | return; |
| 346 | } |
| 347 | |
| 348 | printk(KERN_INFO "DMA-API: debugging enabled by kernel config\n"); |
| 349 | } |
| 350 | |
Joerg Roedel | 59d3daa | 2009-01-09 13:01:56 +0100 | [diff] [blame] | 351 | static __init int dma_debug_cmdline(char *str) |
| 352 | { |
| 353 | if (!str) |
| 354 | return -EINVAL; |
| 355 | |
| 356 | if (strncmp(str, "off", 3) == 0) { |
| 357 | printk(KERN_INFO "DMA-API: debugging disabled on kernel " |
| 358 | "command line\n"); |
| 359 | global_disable = true; |
| 360 | } |
| 361 | |
| 362 | return 0; |
| 363 | } |
| 364 | |
| 365 | static __init int dma_debug_entries_cmdline(char *str) |
| 366 | { |
| 367 | int res; |
| 368 | |
| 369 | if (!str) |
| 370 | return -EINVAL; |
| 371 | |
| 372 | res = get_option(&str, &req_entries); |
| 373 | |
| 374 | if (!res) |
| 375 | req_entries = 0; |
| 376 | |
| 377 | return 0; |
| 378 | } |
| 379 | |
| 380 | __setup("dma_debug=", dma_debug_cmdline); |
| 381 | __setup("dma_debug_entries=", dma_debug_entries_cmdline); |
| 382 | |