forked from Minki/linux
3b1e79ed73
Impact: add allocator code for struct dma_debug_entry Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
201 lines
4.8 KiB
C
201 lines
4.8 KiB
C
/*
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* Copyright (C) 2008 Advanced Micro Devices, Inc.
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*
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* Author: Joerg Roedel <joerg.roedel@amd.com>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published
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* by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include <linux/dma-debug.h>
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#include <linux/spinlock.h>
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#include <linux/types.h>
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#include <linux/list.h>
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#define HASH_SIZE 1024ULL
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#define HASH_FN_SHIFT 13
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#define HASH_FN_MASK (HASH_SIZE - 1)
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enum {
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dma_debug_single,
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dma_debug_page,
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dma_debug_sg,
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dma_debug_coherent,
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};
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struct dma_debug_entry {
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struct list_head list;
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struct device *dev;
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int type;
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phys_addr_t paddr;
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u64 dev_addr;
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u64 size;
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int direction;
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int sg_call_ents;
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int sg_mapped_ents;
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};
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struct hash_bucket {
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struct list_head list;
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spinlock_t lock;
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} __cacheline_aligned_in_smp;
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/* Hash list to save the allocated dma addresses */
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static struct hash_bucket dma_entry_hash[HASH_SIZE];
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/* List of pre-allocated dma_debug_entry's */
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static LIST_HEAD(free_entries);
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/* Lock for the list above */
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static DEFINE_SPINLOCK(free_entries_lock);
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/* Global disable flag - will be set in case of an error */
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static bool global_disable __read_mostly;
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static u32 num_free_entries;
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static u32 min_free_entries;
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/*
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* Hash related functions
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*
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* Every DMA-API request is saved into a struct dma_debug_entry. To
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* have quick access to these structs they are stored into a hash.
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*/
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static int hash_fn(struct dma_debug_entry *entry)
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{
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/*
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* Hash function is based on the dma address.
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* We use bits 20-27 here as the index into the hash
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*/
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return (entry->dev_addr >> HASH_FN_SHIFT) & HASH_FN_MASK;
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}
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/*
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* Request exclusive access to a hash bucket for a given dma_debug_entry.
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*/
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static struct hash_bucket *get_hash_bucket(struct dma_debug_entry *entry,
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unsigned long *flags)
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{
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int idx = hash_fn(entry);
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unsigned long __flags;
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spin_lock_irqsave(&dma_entry_hash[idx].lock, __flags);
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*flags = __flags;
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return &dma_entry_hash[idx];
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}
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/*
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* Give up exclusive access to the hash bucket
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*/
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static void put_hash_bucket(struct hash_bucket *bucket,
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unsigned long *flags)
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{
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unsigned long __flags = *flags;
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spin_unlock_irqrestore(&bucket->lock, __flags);
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}
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/*
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* Search a given entry in the hash bucket list
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*/
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static struct dma_debug_entry *hash_bucket_find(struct hash_bucket *bucket,
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struct dma_debug_entry *ref)
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{
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struct dma_debug_entry *entry;
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list_for_each_entry(entry, &bucket->list, list) {
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if ((entry->dev_addr == ref->dev_addr) &&
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(entry->dev == ref->dev))
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return entry;
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}
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return NULL;
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}
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/*
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* Add an entry to a hash bucket
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*/
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static void hash_bucket_add(struct hash_bucket *bucket,
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struct dma_debug_entry *entry)
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{
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list_add_tail(&entry->list, &bucket->list);
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}
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/*
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* Remove entry from a hash bucket list
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*/
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static void hash_bucket_del(struct dma_debug_entry *entry)
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{
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list_del(&entry->list);
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}
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/*
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* Wrapper function for adding an entry to the hash.
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* This function takes care of locking itself.
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*/
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static void add_dma_entry(struct dma_debug_entry *entry)
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{
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struct hash_bucket *bucket;
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unsigned long flags;
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bucket = get_hash_bucket(entry, &flags);
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hash_bucket_add(bucket, entry);
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put_hash_bucket(bucket, &flags);
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}
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/* struct dma_entry allocator
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*
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* The next two functions implement the allocator for
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* struct dma_debug_entries.
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*/
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static struct dma_debug_entry *dma_entry_alloc(void)
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{
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struct dma_debug_entry *entry = NULL;
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unsigned long flags;
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spin_lock_irqsave(&free_entries_lock, flags);
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if (list_empty(&free_entries)) {
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printk(KERN_ERR "DMA-API: debugging out of memory "
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"- disabling\n");
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global_disable = true;
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goto out;
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}
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entry = list_entry(free_entries.next, struct dma_debug_entry, list);
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list_del(&entry->list);
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memset(entry, 0, sizeof(*entry));
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num_free_entries -= 1;
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if (num_free_entries < min_free_entries)
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min_free_entries = num_free_entries;
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out:
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spin_unlock_irqrestore(&free_entries_lock, flags);
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return entry;
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}
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static void dma_entry_free(struct dma_debug_entry *entry)
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{
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unsigned long flags;
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/*
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* add to beginning of the list - this way the entries are
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* more likely cache hot when they are reallocated.
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*/
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spin_lock_irqsave(&free_entries_lock, flags);
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list_add(&entry->list, &free_entries);
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num_free_entries += 1;
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spin_unlock_irqrestore(&free_entries_lock, flags);
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}
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