summaryrefslogtreecommitdiffstats
path: root/mm/dmapool.c
diff options
context:
space:
mode:
Diffstat (limited to '')
-rw-r--r--mm/dmapool.c524
1 files changed, 524 insertions, 0 deletions
diff --git a/mm/dmapool.c b/mm/dmapool.c
new file mode 100644
index 0000000000..a151a21e57
--- /dev/null
+++ b/mm/dmapool.c
@@ -0,0 +1,524 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * DMA Pool allocator
+ *
+ * Copyright 2001 David Brownell
+ * Copyright 2007 Intel Corporation
+ * Author: Matthew Wilcox <willy@linux.intel.com>
+ *
+ * This allocator returns small blocks of a given size which are DMA-able by
+ * the given device. It uses the dma_alloc_coherent page allocator to get
+ * new pages, then splits them up into blocks of the required size.
+ * Many older drivers still have their own code to do this.
+ *
+ * The current design of this allocator is fairly simple. The pool is
+ * represented by the 'struct dma_pool' which keeps a doubly-linked list of
+ * allocated pages. Each page in the page_list is split into blocks of at
+ * least 'size' bytes. Free blocks are tracked in an unsorted singly-linked
+ * list of free blocks across all pages. Used blocks aren't tracked, but we
+ * keep a count of how many are currently allocated from each page.
+ */
+
+#include <linux/device.h>
+#include <linux/dma-mapping.h>
+#include <linux/dmapool.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/export.h>
+#include <linux/mutex.h>
+#include <linux/poison.h>
+#include <linux/sched.h>
+#include <linux/sched/mm.h>
+#include <linux/slab.h>
+#include <linux/stat.h>
+#include <linux/spinlock.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/wait.h>
+
+#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB_DEBUG_ON)
+#define DMAPOOL_DEBUG 1
+#endif
+
+struct dma_block {
+ struct dma_block *next_block;
+ dma_addr_t dma;
+};
+
+struct dma_pool { /* the pool */
+ struct list_head page_list;
+ spinlock_t lock;
+ struct dma_block *next_block;
+ size_t nr_blocks;
+ size_t nr_active;
+ size_t nr_pages;
+ struct device *dev;
+ unsigned int size;
+ unsigned int allocation;
+ unsigned int boundary;
+ char name[32];
+ struct list_head pools;
+};
+
+struct dma_page { /* cacheable header for 'allocation' bytes */
+ struct list_head page_list;
+ void *vaddr;
+ dma_addr_t dma;
+};
+
+static DEFINE_MUTEX(pools_lock);
+static DEFINE_MUTEX(pools_reg_lock);
+
+static ssize_t pools_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ struct dma_pool *pool;
+ unsigned size;
+
+ size = sysfs_emit(buf, "poolinfo - 0.1\n");
+
+ mutex_lock(&pools_lock);
+ list_for_each_entry(pool, &dev->dma_pools, pools) {
+ /* per-pool info, no real statistics yet */
+ size += sysfs_emit_at(buf, size, "%-16s %4zu %4zu %4u %2zu\n",
+ pool->name, pool->nr_active,
+ pool->nr_blocks, pool->size,
+ pool->nr_pages);
+ }
+ mutex_unlock(&pools_lock);
+
+ return size;
+}
+
+static DEVICE_ATTR_RO(pools);
+
+#ifdef DMAPOOL_DEBUG
+static void pool_check_block(struct dma_pool *pool, struct dma_block *block,
+ gfp_t mem_flags)
+{
+ u8 *data = (void *)block;
+ int i;
+
+ for (i = sizeof(struct dma_block); i < pool->size; i++) {
+ if (data[i] == POOL_POISON_FREED)
+ continue;
+ dev_err(pool->dev, "%s %s, %p (corrupted)\n", __func__,
+ pool->name, block);
+
+ /*
+ * Dump the first 4 bytes even if they are not
+ * POOL_POISON_FREED
+ */
+ print_hex_dump(KERN_ERR, "", DUMP_PREFIX_OFFSET, 16, 1,
+ data, pool->size, 1);
+ break;
+ }
+
+ if (!want_init_on_alloc(mem_flags))
+ memset(block, POOL_POISON_ALLOCATED, pool->size);
+}
+
+static struct dma_page *pool_find_page(struct dma_pool *pool, dma_addr_t dma)
+{
+ struct dma_page *page;
+
+ list_for_each_entry(page, &pool->page_list, page_list) {
+ if (dma < page->dma)
+ continue;
+ if ((dma - page->dma) < pool->allocation)
+ return page;
+ }
+ return NULL;
+}
+
+static bool pool_block_err(struct dma_pool *pool, void *vaddr, dma_addr_t dma)
+{
+ struct dma_block *block = pool->next_block;
+ struct dma_page *page;
+
+ page = pool_find_page(pool, dma);
+ if (!page) {
+ dev_err(pool->dev, "%s %s, %p/%pad (bad dma)\n",
+ __func__, pool->name, vaddr, &dma);
+ return true;
+ }
+
+ while (block) {
+ if (block != vaddr) {
+ block = block->next_block;
+ continue;
+ }
+ dev_err(pool->dev, "%s %s, dma %pad already free\n",
+ __func__, pool->name, &dma);
+ return true;
+ }
+
+ memset(vaddr, POOL_POISON_FREED, pool->size);
+ return false;
+}
+
+static void pool_init_page(struct dma_pool *pool, struct dma_page *page)
+{
+ memset(page->vaddr, POOL_POISON_FREED, pool->allocation);
+}
+#else
+static void pool_check_block(struct dma_pool *pool, struct dma_block *block,
+ gfp_t mem_flags)
+{
+}
+
+static bool pool_block_err(struct dma_pool *pool, void *vaddr, dma_addr_t dma)
+{
+ if (want_init_on_free())
+ memset(vaddr, 0, pool->size);
+ return false;
+}
+
+static void pool_init_page(struct dma_pool *pool, struct dma_page *page)
+{
+}
+#endif
+
+static struct dma_block *pool_block_pop(struct dma_pool *pool)
+{
+ struct dma_block *block = pool->next_block;
+
+ if (block) {
+ pool->next_block = block->next_block;
+ pool->nr_active++;
+ }
+ return block;
+}
+
+static void pool_block_push(struct dma_pool *pool, struct dma_block *block,
+ dma_addr_t dma)
+{
+ block->dma = dma;
+ block->next_block = pool->next_block;
+ pool->next_block = block;
+}
+
+
+/**
+ * dma_pool_create - Creates a pool of consistent memory blocks, for dma.
+ * @name: name of pool, for diagnostics
+ * @dev: device that will be doing the DMA
+ * @size: size of the blocks in this pool.
+ * @align: alignment requirement for blocks; must be a power of two
+ * @boundary: returned blocks won't cross this power of two boundary
+ * Context: not in_interrupt()
+ *
+ * Given one of these pools, dma_pool_alloc()
+ * may be used to allocate memory. Such memory will all have "consistent"
+ * DMA mappings, accessible by the device and its driver without using
+ * cache flushing primitives. The actual size of blocks allocated may be
+ * larger than requested because of alignment.
+ *
+ * If @boundary is nonzero, objects returned from dma_pool_alloc() won't
+ * cross that size boundary. This is useful for devices which have
+ * addressing restrictions on individual DMA transfers, such as not crossing
+ * boundaries of 4KBytes.
+ *
+ * Return: a dma allocation pool with the requested characteristics, or
+ * %NULL if one can't be created.
+ */
+struct dma_pool *dma_pool_create(const char *name, struct device *dev,
+ size_t size, size_t align, size_t boundary)
+{
+ struct dma_pool *retval;
+ size_t allocation;
+ bool empty;
+
+ if (!dev)
+ return NULL;
+
+ if (align == 0)
+ align = 1;
+ else if (align & (align - 1))
+ return NULL;
+
+ if (size == 0 || size > INT_MAX)
+ return NULL;
+ if (size < sizeof(struct dma_block))
+ size = sizeof(struct dma_block);
+
+ size = ALIGN(size, align);
+ allocation = max_t(size_t, size, PAGE_SIZE);
+
+ if (!boundary)
+ boundary = allocation;
+ else if ((boundary < size) || (boundary & (boundary - 1)))
+ return NULL;
+
+ boundary = min(boundary, allocation);
+
+ retval = kzalloc(sizeof(*retval), GFP_KERNEL);
+ if (!retval)
+ return retval;
+
+ strscpy(retval->name, name, sizeof(retval->name));
+
+ retval->dev = dev;
+
+ INIT_LIST_HEAD(&retval->page_list);
+ spin_lock_init(&retval->lock);
+ retval->size = size;
+ retval->boundary = boundary;
+ retval->allocation = allocation;
+ INIT_LIST_HEAD(&retval->pools);
+
+ /*
+ * pools_lock ensures that the ->dma_pools list does not get corrupted.
+ * pools_reg_lock ensures that there is not a race between
+ * dma_pool_create() and dma_pool_destroy() or within dma_pool_create()
+ * when the first invocation of dma_pool_create() failed on
+ * device_create_file() and the second assumes that it has been done (I
+ * know it is a short window).
+ */
+ mutex_lock(&pools_reg_lock);
+ mutex_lock(&pools_lock);
+ empty = list_empty(&dev->dma_pools);
+ list_add(&retval->pools, &dev->dma_pools);
+ mutex_unlock(&pools_lock);
+ if (empty) {
+ int err;
+
+ err = device_create_file(dev, &dev_attr_pools);
+ if (err) {
+ mutex_lock(&pools_lock);
+ list_del(&retval->pools);
+ mutex_unlock(&pools_lock);
+ mutex_unlock(&pools_reg_lock);
+ kfree(retval);
+ return NULL;
+ }
+ }
+ mutex_unlock(&pools_reg_lock);
+ return retval;
+}
+EXPORT_SYMBOL(dma_pool_create);
+
+static void pool_initialise_page(struct dma_pool *pool, struct dma_page *page)
+{
+ unsigned int next_boundary = pool->boundary, offset = 0;
+ struct dma_block *block, *first = NULL, *last = NULL;
+
+ pool_init_page(pool, page);
+ while (offset + pool->size <= pool->allocation) {
+ if (offset + pool->size > next_boundary) {
+ offset = next_boundary;
+ next_boundary += pool->boundary;
+ continue;
+ }
+
+ block = page->vaddr + offset;
+ block->dma = page->dma + offset;
+ block->next_block = NULL;
+
+ if (last)
+ last->next_block = block;
+ else
+ first = block;
+ last = block;
+
+ offset += pool->size;
+ pool->nr_blocks++;
+ }
+
+ last->next_block = pool->next_block;
+ pool->next_block = first;
+
+ list_add(&page->page_list, &pool->page_list);
+ pool->nr_pages++;
+}
+
+static struct dma_page *pool_alloc_page(struct dma_pool *pool, gfp_t mem_flags)
+{
+ struct dma_page *page;
+
+ page = kmalloc(sizeof(*page), mem_flags);
+ if (!page)
+ return NULL;
+
+ page->vaddr = dma_alloc_coherent(pool->dev, pool->allocation,
+ &page->dma, mem_flags);
+ if (!page->vaddr) {
+ kfree(page);
+ return NULL;
+ }
+
+ return page;
+}
+
+/**
+ * dma_pool_destroy - destroys a pool of dma memory blocks.
+ * @pool: dma pool that will be destroyed
+ * Context: !in_interrupt()
+ *
+ * Caller guarantees that no more memory from the pool is in use,
+ * and that nothing will try to use the pool after this call.
+ */
+void dma_pool_destroy(struct dma_pool *pool)
+{
+ struct dma_page *page, *tmp;
+ bool empty, busy = false;
+
+ if (unlikely(!pool))
+ return;
+
+ mutex_lock(&pools_reg_lock);
+ mutex_lock(&pools_lock);
+ list_del(&pool->pools);
+ empty = list_empty(&pool->dev->dma_pools);
+ mutex_unlock(&pools_lock);
+ if (empty)
+ device_remove_file(pool->dev, &dev_attr_pools);
+ mutex_unlock(&pools_reg_lock);
+
+ if (pool->nr_active) {
+ dev_err(pool->dev, "%s %s busy\n", __func__, pool->name);
+ busy = true;
+ }
+
+ list_for_each_entry_safe(page, tmp, &pool->page_list, page_list) {
+ if (!busy)
+ dma_free_coherent(pool->dev, pool->allocation,
+ page->vaddr, page->dma);
+ list_del(&page->page_list);
+ kfree(page);
+ }
+
+ kfree(pool);
+}
+EXPORT_SYMBOL(dma_pool_destroy);
+
+/**
+ * dma_pool_alloc - get a block of consistent memory
+ * @pool: dma pool that will produce the block
+ * @mem_flags: GFP_* bitmask
+ * @handle: pointer to dma address of block
+ *
+ * Return: the kernel virtual address of a currently unused block,
+ * and reports its dma address through the handle.
+ * If such a memory block can't be allocated, %NULL is returned.
+ */
+void *dma_pool_alloc(struct dma_pool *pool, gfp_t mem_flags,
+ dma_addr_t *handle)
+{
+ struct dma_block *block;
+ struct dma_page *page;
+ unsigned long flags;
+
+ might_alloc(mem_flags);
+
+ spin_lock_irqsave(&pool->lock, flags);
+ block = pool_block_pop(pool);
+ if (!block) {
+ /*
+ * pool_alloc_page() might sleep, so temporarily drop
+ * &pool->lock
+ */
+ spin_unlock_irqrestore(&pool->lock, flags);
+
+ page = pool_alloc_page(pool, mem_flags & (~__GFP_ZERO));
+ if (!page)
+ return NULL;
+
+ spin_lock_irqsave(&pool->lock, flags);
+ pool_initialise_page(pool, page);
+ block = pool_block_pop(pool);
+ }
+ spin_unlock_irqrestore(&pool->lock, flags);
+
+ *handle = block->dma;
+ pool_check_block(pool, block, mem_flags);
+ if (want_init_on_alloc(mem_flags))
+ memset(block, 0, pool->size);
+
+ return block;
+}
+EXPORT_SYMBOL(dma_pool_alloc);
+
+/**
+ * dma_pool_free - put block back into dma pool
+ * @pool: the dma pool holding the block
+ * @vaddr: virtual address of block
+ * @dma: dma address of block
+ *
+ * Caller promises neither device nor driver will again touch this block
+ * unless it is first re-allocated.
+ */
+void dma_pool_free(struct dma_pool *pool, void *vaddr, dma_addr_t dma)
+{
+ struct dma_block *block = vaddr;
+ unsigned long flags;
+
+ spin_lock_irqsave(&pool->lock, flags);
+ if (!pool_block_err(pool, vaddr, dma)) {
+ pool_block_push(pool, block, dma);
+ pool->nr_active--;
+ }
+ spin_unlock_irqrestore(&pool->lock, flags);
+}
+EXPORT_SYMBOL(dma_pool_free);
+
+/*
+ * Managed DMA pool
+ */
+static void dmam_pool_release(struct device *dev, void *res)
+{
+ struct dma_pool *pool = *(struct dma_pool **)res;
+
+ dma_pool_destroy(pool);
+}
+
+static int dmam_pool_match(struct device *dev, void *res, void *match_data)
+{
+ return *(struct dma_pool **)res == match_data;
+}
+
+/**
+ * dmam_pool_create - Managed dma_pool_create()
+ * @name: name of pool, for diagnostics
+ * @dev: device that will be doing the DMA
+ * @size: size of the blocks in this pool.
+ * @align: alignment requirement for blocks; must be a power of two
+ * @allocation: returned blocks won't cross this boundary (or zero)
+ *
+ * Managed dma_pool_create(). DMA pool created with this function is
+ * automatically destroyed on driver detach.
+ *
+ * Return: a managed dma allocation pool with the requested
+ * characteristics, or %NULL if one can't be created.
+ */
+struct dma_pool *dmam_pool_create(const char *name, struct device *dev,
+ size_t size, size_t align, size_t allocation)
+{
+ struct dma_pool **ptr, *pool;
+
+ ptr = devres_alloc(dmam_pool_release, sizeof(*ptr), GFP_KERNEL);
+ if (!ptr)
+ return NULL;
+
+ pool = *ptr = dma_pool_create(name, dev, size, align, allocation);
+ if (pool)
+ devres_add(dev, ptr);
+ else
+ devres_free(ptr);
+
+ return pool;
+}
+EXPORT_SYMBOL(dmam_pool_create);
+
+/**
+ * dmam_pool_destroy - Managed dma_pool_destroy()
+ * @pool: dma pool that will be destroyed
+ *
+ * Managed dma_pool_destroy().
+ */
+void dmam_pool_destroy(struct dma_pool *pool)
+{
+ struct device *dev = pool->dev;
+
+ WARN_ON(devres_release(dev, dmam_pool_release, dmam_pool_match, pool));
+}
+EXPORT_SYMBOL(dmam_pool_destroy);