[linux-2.6-block.git] / lib / dma-debug.c

/*
 * Copyright (C) 2008 Advanced Micro Devices, Inc.
 *
 * Author: Joerg Roedel <joerg.roedel@amd.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published
 * by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 */

#include <linux/dma-debug.h>
#include <linux/spinlock.h>
#include <linux/debugfs.h>
#include <linux/types.h>
#include <linux/list.h>
#include <linux/slab.h>

#define HASH_SIZE       1024ULL
#define HASH_FN_SHIFT   13
#define HASH_FN_MASK    (HASH_SIZE - 1)

enum {
	dma_debug_single,
	dma_debug_page,
	dma_debug_sg,
	dma_debug_coherent,
};

struct dma_debug_entry {
	struct list_head list;
	struct device    *dev;
	int              type;
	phys_addr_t      paddr;
	u64              dev_addr;
	u64              size;
	int              direction;
	int		 sg_call_ents;
	int		 sg_mapped_ents;
};

struct hash_bucket {
	struct list_head list;
	spinlock_t lock;
} __cacheline_aligned_in_smp;

/* Hash list to save the allocated dma addresses */
static struct hash_bucket dma_entry_hash[HASH_SIZE];
/* List of pre-allocated dma_debug_entry's */
static LIST_HEAD(free_entries);
/* Lock for the list above */
static DEFINE_SPINLOCK(free_entries_lock);

/* Global disable flag - will be set in case of an error */
static bool global_disable __read_mostly;

/* Global error count */
static u32 error_count;

/* Global error show enable*/
static u32 show_all_errors __read_mostly;
/* Number of errors to show */
static u32 show_num_errors = 1;

static u32 num_free_entries;
static u32 min_free_entries;

/* number of preallocated entries requested by kernel cmdline */
static u32 req_entries;

/* debugfs dentry's for the stuff above */
static struct dentry *dma_debug_dent        __read_mostly;
static struct dentry *global_disable_dent   __read_mostly;
static struct dentry *error_count_dent      __read_mostly;
static struct dentry *show_all_errors_dent  __read_mostly;
static struct dentry *show_num_errors_dent  __read_mostly;
static struct dentry *num_free_entries_dent __read_mostly;
static struct dentry *min_free_entries_dent __read_mostly;

/*
 * Hash related functions
 *
 * Every DMA-API request is saved into a struct dma_debug_entry. To
 * have quick access to these structs they are stored into a hash.
 */
static int hash_fn(struct dma_debug_entry *entry)
{
	/*
	 * Hash function is based on the dma address.
	 * We use bits 20-27 here as the index into the hash
	 */
	return (entry->dev_addr >> HASH_FN_SHIFT) & HASH_FN_MASK;
}

/*
 * Request exclusive access to a hash bucket for a given dma_debug_entry.
 */
static struct hash_bucket *get_hash_bucket(struct dma_debug_entry *entry,
					   unsigned long *flags)
{
	int idx = hash_fn(entry);
	unsigned long __flags;

	spin_lock_irqsave(&dma_entry_hash[idx].lock, __flags);
	*flags = __flags;
	return &dma_entry_hash[idx];
}

/*
 * Give up exclusive access to the hash bucket
 */
static void put_hash_bucket(struct hash_bucket *bucket,
			    unsigned long *flags)
{
	unsigned long __flags = *flags;

	spin_unlock_irqrestore(&bucket->lock, __flags);
}

/*
 * Search a given entry in the hash bucket list
 */
static struct dma_debug_entry *hash_bucket_find(struct hash_bucket *bucket,
						struct dma_debug_entry *ref)
{
	struct dma_debug_entry *entry;

	list_for_each_entry(entry, &bucket->list, list) {
		if ((entry->dev_addr == ref->dev_addr) &&
		    (entry->dev == ref->dev))
			return entry;
	}

	return NULL;
}

/*
 * Add an entry to a hash bucket
 */
static void hash_bucket_add(struct hash_bucket *bucket,
			    struct dma_debug_entry *entry)
{
	list_add_tail(&entry->list, &bucket->list);
}

/*
 * Remove entry from a hash bucket list
 */
static void hash_bucket_del(struct dma_debug_entry *entry)
{
	list_del(&entry->list);
}

/*
 * Wrapper function for adding an entry to the hash.
 * This function takes care of locking itself.
 */
static void add_dma_entry(struct dma_debug_entry *entry)
{
	struct hash_bucket *bucket;
	unsigned long flags;

	bucket = get_hash_bucket(entry, &flags);
	hash_bucket_add(bucket, entry);
	put_hash_bucket(bucket, &flags);
}

/* struct dma_entry allocator
 *
 * The next two functions implement the allocator for
 * struct dma_debug_entries.
 */
static struct dma_debug_entry *dma_entry_alloc(void)
{
	struct dma_debug_entry *entry = NULL;
	unsigned long flags;

	spin_lock_irqsave(&free_entries_lock, flags);

	if (list_empty(&free_entries)) {
		printk(KERN_ERR "DMA-API: debugging out of memory "
				"- disabling\n");
		global_disable = true;
		goto out;
	}

	entry = list_entry(free_entries.next, struct dma_debug_entry, list);
	list_del(&entry->list);
	memset(entry, 0, sizeof(*entry));

	num_free_entries -= 1;
	if (num_free_entries < min_free_entries)
		min_free_entries = num_free_entries;

out:
	spin_unlock_irqrestore(&free_entries_lock, flags);

	return entry;
}

static void dma_entry_free(struct dma_debug_entry *entry)
{
	unsigned long flags;

	/*
	 * add to beginning of the list - this way the entries are
	 * more likely cache hot when they are reallocated.
	 */
	spin_lock_irqsave(&free_entries_lock, flags);
	list_add(&entry->list, &free_entries);
	num_free_entries += 1;
	spin_unlock_irqrestore(&free_entries_lock, flags);
}

/*
 * DMA-API debugging init code
 *
 * The init code does two things:
 *   1. Initialize core data structures
 *   2. Preallocate a given number of dma_debug_entry structs
 */

static int prealloc_memory(u32 num_entries)
{
	struct dma_debug_entry *entry, *next_entry;
	int i;

	for (i = 0; i < num_entries; ++i) {
		entry = kzalloc(sizeof(*entry), GFP_KERNEL);
		if (!entry)
			goto out_err;

		list_add_tail(&entry->list, &free_entries);
	}

	num_free_entries = num_entries;
	min_free_entries = num_entries;

	printk(KERN_INFO "DMA-API: preallocated %d debug entries\n",
			num_entries);

	return 0;

out_err:

	list_for_each_entry_safe(entry, next_entry, &free_entries, list) {
		list_del(&entry->list);
		kfree(entry);
	}

	return -ENOMEM;
}

static int dma_debug_fs_init(void)
{
	dma_debug_dent = debugfs_create_dir("dma-api", NULL);
	if (!dma_debug_dent) {
		printk(KERN_ERR "DMA-API: can not create debugfs directory\n");
		return -ENOMEM;
	}

	global_disable_dent = debugfs_create_bool("disabled", 0444,
			dma_debug_dent,
			(u32 *)&global_disable);
	if (!global_disable_dent)
		goto out_err;

	error_count_dent = debugfs_create_u32("error_count", 0444,
			dma_debug_dent, &error_count);
	if (!error_count_dent)
		goto out_err;

	show_all_errors_dent = debugfs_create_u32("all_errors", 0644,
			dma_debug_dent,
			&show_all_errors);
	if (!show_all_errors_dent)
		goto out_err;

	show_num_errors_dent = debugfs_create_u32("num_errors", 0644,
			dma_debug_dent,
			&show_num_errors);
	if (!show_num_errors_dent)
		goto out_err;

	num_free_entries_dent = debugfs_create_u32("num_free_entries", 0444,
			dma_debug_dent,
			&num_free_entries);
	if (!num_free_entries_dent)
		goto out_err;

	min_free_entries_dent = debugfs_create_u32("min_free_entries", 0444,
			dma_debug_dent,
			&min_free_entries);
	if (!min_free_entries_dent)
		goto out_err;

	return 0;

out_err:
	debugfs_remove_recursive(dma_debug_dent);

	return -ENOMEM;
}


/*
 * Let the architectures decide how many entries should be preallocated.
 */
void dma_debug_init(u32 num_entries)
{
	int i;

	if (global_disable)
		return;

	for (i = 0; i < HASH_SIZE; ++i) {
		INIT_LIST_HEAD(&dma_entry_hash[i].list);
		dma_entry_hash[i].lock = SPIN_LOCK_UNLOCKED;
	}

	if (dma_debug_fs_init() != 0) {
		printk(KERN_ERR "DMA-API: error creating debugfs entries "
				"- disabling\n");
		global_disable = true;

		return;
	}

	if (req_entries)
		num_entries = req_entries;

	if (prealloc_memory(num_entries) != 0) {
		printk(KERN_ERR "DMA-API: debugging out of memory error "
				"- disabled\n");
		global_disable = true;

		return;
	}

	printk(KERN_INFO "DMA-API: debugging enabled by kernel config\n");
}

static __init int dma_debug_cmdline(char *str)
{
	if (!str)
		return -EINVAL;

	if (strncmp(str, "off", 3) == 0) {
		printk(KERN_INFO "DMA-API: debugging disabled on kernel "
				 "command line\n");
		global_disable = true;
	}

	return 0;
}

static __init int dma_debug_entries_cmdline(char *str)
{
	int res;

	if (!str)
		return -EINVAL;

	res = get_option(&str, &req_entries);

	if (!res)
		req_entries = 0;

	return 0;
}

__setup("dma_debug=", dma_debug_cmdline);
__setup("dma_debug_entries=", dma_debug_entries_cmdline);
Commit	Line	Data
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>
788dcfa6	22	#include <linux/debugfs.h>
f2f45e5f JR	23	#include <linux/types.h>
f2f45e5f JR	24	#include <linux/list.h>
6bf07871	25	#include <linux/slab.h>
f2f45e5f	26
30dfa90c JR	27	#define HASH_SIZE 1024ULL
	28	#define HASH_FN_SHIFT 13
	29	#define HASH_FN_MASK (HASH_SIZE - 1)
	30
f2f45e5f JR	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
30dfa90c JR	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];
3b1e79ed JR	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
788dcfa6 JR	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
3b1e79ed JR	73	static u32 num_free_entries;
3b1e79ed JR	74	static u32 min_free_entries;
30dfa90c	75
59d3daaf JR	76	/* number of preallocated entries requested by kernel cmdline */
	77	static u32 req_entries;
	78
788dcfa6 JR	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
30dfa90c JR	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
3b1e79ed JR	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
6bf07871 JR	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
788dcfa6 JR	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
6bf07871 JR	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
788dcfa6 JR	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
59d3daaf JR	337	if (req_entries)
	338	num_entries = req_entries;
	339
6bf07871 JR	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
59d3daaf JR	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