1 files changed, 524 insertions, 0 deletions
diff --git a/mm/dmapool.c b/mm/dmapool.c
new file mode 100644
index 000000000..a151a21e5
--- /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);