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@@ -0,0 +1,500 @@
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+/*
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+ * DMA Pool allocator
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+ *
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+ * Copyright 2001 David Brownell
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+ * Copyright 2007 Intel Corporation
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+ * Author: Matthew Wilcox <willy@linux.intel.com>
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+ *
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+ * This software may be redistributed and/or modified under the terms of
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+ * the GNU General Public License ("GPL") version 2 as published by the
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+ * Free Software Foundation.
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+ *
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+ * This allocator returns small blocks of a given size which are DMA-able by
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+ * the given device. It uses the dma_alloc_coherent page allocator to get
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+ * new pages, then splits them up into blocks of the required size.
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+ * Many older drivers still have their own code to do this.
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+ *
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+ * The current design of this allocator is fairly simple. The pool is
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+ * represented by the 'struct dma_pool' which keeps a doubly-linked list of
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+ * allocated pages. Each page in the page_list is split into blocks of at
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+ * least 'size' bytes. Free blocks are tracked in an unsorted singly-linked
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+ * list of free blocks within the page. Used blocks aren't tracked, but we
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+ * keep a count of how many are currently allocated from each page.
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+ */
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+
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+#include <linux/device.h>
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+#include <linux/dma-mapping.h>
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+#include <linux/dmapool.h>
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+#include <linux/kernel.h>
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+#include <linux/list.h>
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+#include <linux/module.h>
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+#include <linux/mutex.h>
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+#include <linux/poison.h>
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+#include <linux/sched.h>
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+#include <linux/slab.h>
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+#include <linux/spinlock.h>
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+#include <linux/string.h>
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+#include <linux/types.h>
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+#include <linux/wait.h>
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+
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+struct dma_pool { /* the pool */
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+ struct list_head page_list;
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+ spinlock_t lock;
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+ size_t size;
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+ struct device *dev;
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+ size_t allocation;
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+ size_t boundary;
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+ char name[32];
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+ wait_queue_head_t waitq;
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+ struct list_head pools;
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+};
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+
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+struct dma_page { /* cacheable header for 'allocation' bytes */
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+ struct list_head page_list;
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+ void *vaddr;
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+ dma_addr_t dma;
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+ unsigned int in_use;
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+ unsigned int offset;
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+};
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+
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+#define POOL_TIMEOUT_JIFFIES ((100 /* msec */ * HZ) / 1000)
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+
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+static DEFINE_MUTEX(pools_lock);
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+
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+static ssize_t
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+show_pools(struct device *dev, struct device_attribute *attr, char *buf)
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+{
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+ unsigned temp;
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+ unsigned size;
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+ char *next;
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+ struct dma_page *page;
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+ struct dma_pool *pool;
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+
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+ next = buf;
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+ size = PAGE_SIZE;
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+
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+ temp = scnprintf(next, size, "poolinfo - 0.1\n");
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+ size -= temp;
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+ next += temp;
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+
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+ mutex_lock(&pools_lock);
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+ list_for_each_entry(pool, &dev->dma_pools, pools) {
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+ unsigned pages = 0;
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+ unsigned blocks = 0;
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+
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+ list_for_each_entry(page, &pool->page_list, page_list) {
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+ pages++;
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+ blocks += page->in_use;
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+ }
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+
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+ /* per-pool info, no real statistics yet */
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+ temp = scnprintf(next, size, "%-16s %4u %4Zu %4Zu %2u\n",
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+ pool->name, blocks,
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+ pages * (pool->allocation / pool->size),
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+ pool->size, pages);
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+ size -= temp;
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+ next += temp;
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+ }
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+ mutex_unlock(&pools_lock);
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+
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+ return PAGE_SIZE - size;
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+}
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+
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+static DEVICE_ATTR(pools, S_IRUGO, show_pools, NULL);
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+
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+/**
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+ * dma_pool_create - Creates a pool of consistent memory blocks, for dma.
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+ * @name: name of pool, for diagnostics
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+ * @dev: device that will be doing the DMA
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+ * @size: size of the blocks in this pool.
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+ * @align: alignment requirement for blocks; must be a power of two
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+ * @boundary: returned blocks won't cross this power of two boundary
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+ * Context: !in_interrupt()
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+ *
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+ * Returns a dma allocation pool with the requested characteristics, or
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+ * null if one can't be created. Given one of these pools, dma_pool_alloc()
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+ * may be used to allocate memory. Such memory will all have "consistent"
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+ * DMA mappings, accessible by the device and its driver without using
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+ * cache flushing primitives. The actual size of blocks allocated may be
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+ * larger than requested because of alignment.
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+ *
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+ * If @boundary is nonzero, objects returned from dma_pool_alloc() won't
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+ * cross that size boundary. This is useful for devices which have
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+ * addressing restrictions on individual DMA transfers, such as not crossing
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+ * boundaries of 4KBytes.
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+ */
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+struct dma_pool *dma_pool_create(const char *name, struct device *dev,
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+ size_t size, size_t align, size_t boundary)
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+{
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+ struct dma_pool *retval;
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+ size_t allocation;
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+
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+ if (align == 0) {
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+ align = 1;
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+ } else if (align & (align - 1)) {
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+ return NULL;
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+ }
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+
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+ if (size == 0) {
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+ return NULL;
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+ } else if (size < 4) {
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+ size = 4;
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+ }
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+
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+ if ((size % align) != 0)
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+ size = ALIGN(size, align);
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+
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+ allocation = max_t(size_t, size, PAGE_SIZE);
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+
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+ if (!boundary) {
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+ boundary = allocation;
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+ } else if ((boundary < size) || (boundary & (boundary - 1))) {
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+ return NULL;
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+ }
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+
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+ retval = kmalloc_node(sizeof(*retval), GFP_KERNEL, dev_to_node(dev));
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+ if (!retval)
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+ return retval;
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+
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+ strlcpy(retval->name, name, sizeof(retval->name));
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+
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+ retval->dev = dev;
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+
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+ INIT_LIST_HEAD(&retval->page_list);
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+ spin_lock_init(&retval->lock);
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+ retval->size = size;
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+ retval->boundary = boundary;
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+ retval->allocation = allocation;
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+ init_waitqueue_head(&retval->waitq);
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+
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+ if (dev) {
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+ int ret;
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+
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+ mutex_lock(&pools_lock);
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+ if (list_empty(&dev->dma_pools))
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+ ret = device_create_file(dev, &dev_attr_pools);
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+ else
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+ ret = 0;
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+ /* note: not currently insisting "name" be unique */
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+ if (!ret)
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+ list_add(&retval->pools, &dev->dma_pools);
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+ else {
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+ kfree(retval);
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+ retval = NULL;
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+ }
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+ mutex_unlock(&pools_lock);
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+ } else
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+ INIT_LIST_HEAD(&retval->pools);
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+
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+ return retval;
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+}
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+EXPORT_SYMBOL(dma_pool_create);
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+
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+static void pool_initialise_page(struct dma_pool *pool, struct dma_page *page)
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+{
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+ unsigned int offset = 0;
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+ unsigned int next_boundary = pool->boundary;
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+
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+ do {
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+ unsigned int next = offset + pool->size;
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+ if (unlikely((next + pool->size) >= next_boundary)) {
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+ next = next_boundary;
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+ next_boundary += pool->boundary;
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+ }
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+ *(int *)(page->vaddr + offset) = next;
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+ offset = next;
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+ } while (offset < pool->allocation);
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+}
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+
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+static struct dma_page *pool_alloc_page(struct dma_pool *pool, gfp_t mem_flags)
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+{
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+ struct dma_page *page;
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+
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+ page = kmalloc(sizeof(*page), mem_flags);
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+ if (!page)
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+ return NULL;
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+ page->vaddr = dma_alloc_coherent(pool->dev, pool->allocation,
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+ &page->dma, mem_flags);
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+ if (page->vaddr) {
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+#ifdef CONFIG_DEBUG_SLAB
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+ memset(page->vaddr, POOL_POISON_FREED, pool->allocation);
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+#endif
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+ pool_initialise_page(pool, page);
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+ list_add(&page->page_list, &pool->page_list);
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+ page->in_use = 0;
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+ page->offset = 0;
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+ } else {
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+ kfree(page);
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+ page = NULL;
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+ }
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+ return page;
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+}
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+
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+static inline int is_page_busy(struct dma_page *page)
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+{
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+ return page->in_use != 0;
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+}
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+
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+static void pool_free_page(struct dma_pool *pool, struct dma_page *page)
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+{
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+ dma_addr_t dma = page->dma;
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+
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+#ifdef CONFIG_DEBUG_SLAB
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+ memset(page->vaddr, POOL_POISON_FREED, pool->allocation);
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+#endif
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+ dma_free_coherent(pool->dev, pool->allocation, page->vaddr, dma);
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+ list_del(&page->page_list);
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+ kfree(page);
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+}
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+
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+/**
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+ * dma_pool_destroy - destroys a pool of dma memory blocks.
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+ * @pool: dma pool that will be destroyed
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+ * Context: !in_interrupt()
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+ *
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+ * Caller guarantees that no more memory from the pool is in use,
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+ * and that nothing will try to use the pool after this call.
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+ */
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+void dma_pool_destroy(struct dma_pool *pool)
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+{
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+ mutex_lock(&pools_lock);
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+ list_del(&pool->pools);
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+ if (pool->dev && list_empty(&pool->dev->dma_pools))
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+ device_remove_file(pool->dev, &dev_attr_pools);
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+ mutex_unlock(&pools_lock);
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+
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+ while (!list_empty(&pool->page_list)) {
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+ struct dma_page *page;
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+ page = list_entry(pool->page_list.next,
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+ struct dma_page, page_list);
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+ if (is_page_busy(page)) {
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+ if (pool->dev)
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+ dev_err(pool->dev,
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+ "dma_pool_destroy %s, %p busy\n",
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+ pool->name, page->vaddr);
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+ else
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+ printk(KERN_ERR
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+ "dma_pool_destroy %s, %p busy\n",
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+ pool->name, page->vaddr);
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+ /* leak the still-in-use consistent memory */
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+ list_del(&page->page_list);
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+ kfree(page);
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+ } else
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+ pool_free_page(pool, page);
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+ }
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+
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+ kfree(pool);
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+}
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+EXPORT_SYMBOL(dma_pool_destroy);
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+
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+/**
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+ * dma_pool_alloc - get a block of consistent memory
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+ * @pool: dma pool that will produce the block
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+ * @mem_flags: GFP_* bitmask
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+ * @handle: pointer to dma address of block
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+ *
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+ * This returns the kernel virtual address of a currently unused block,
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+ * and reports its dma address through the handle.
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+ * If such a memory block can't be allocated, %NULL is returned.
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+ */
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+void *dma_pool_alloc(struct dma_pool *pool, gfp_t mem_flags,
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+ dma_addr_t *handle)
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+{
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+ unsigned long flags;
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+ struct dma_page *page;
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+ size_t offset;
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+ void *retval;
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+
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+ spin_lock_irqsave(&pool->lock, flags);
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+ restart:
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+ list_for_each_entry(page, &pool->page_list, page_list) {
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+ if (page->offset < pool->allocation)
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+ goto ready;
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+ }
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+ page = pool_alloc_page(pool, GFP_ATOMIC);
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+ if (!page) {
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+ if (mem_flags & __GFP_WAIT) {
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+ DECLARE_WAITQUEUE(wait, current);
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+
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+ __set_current_state(TASK_INTERRUPTIBLE);
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+ __add_wait_queue(&pool->waitq, &wait);
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+ spin_unlock_irqrestore(&pool->lock, flags);
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+
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+ schedule_timeout(POOL_TIMEOUT_JIFFIES);
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+
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+ spin_lock_irqsave(&pool->lock, flags);
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+ __remove_wait_queue(&pool->waitq, &wait);
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+ goto restart;
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+ }
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+ retval = NULL;
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+ goto done;
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+ }
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+
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+ ready:
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+ page->in_use++;
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+ offset = page->offset;
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+ page->offset = *(int *)(page->vaddr + offset);
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+ retval = offset + page->vaddr;
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+ *handle = offset + page->dma;
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+#ifdef CONFIG_DEBUG_SLAB
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+ memset(retval, POOL_POISON_ALLOCATED, pool->size);
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+#endif
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+ done:
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+ spin_unlock_irqrestore(&pool->lock, flags);
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+ return retval;
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+}
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+EXPORT_SYMBOL(dma_pool_alloc);
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+
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+static struct dma_page *pool_find_page(struct dma_pool *pool, dma_addr_t dma)
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+{
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+ unsigned long flags;
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+ struct dma_page *page;
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+
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+ spin_lock_irqsave(&pool->lock, flags);
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+ list_for_each_entry(page, &pool->page_list, page_list) {
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+ if (dma < page->dma)
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+ continue;
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+ if (dma < (page->dma + pool->allocation))
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+ goto done;
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+ }
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+ page = NULL;
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+ done:
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+ spin_unlock_irqrestore(&pool->lock, flags);
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+ return page;
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+}
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+
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+/**
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+ * dma_pool_free - put block back into dma pool
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+ * @pool: the dma pool holding the block
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+ * @vaddr: virtual address of block
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+ * @dma: dma address of block
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+ *
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+ * Caller promises neither device nor driver will again touch this block
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+ * unless it is first re-allocated.
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+ */
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+void dma_pool_free(struct dma_pool *pool, void *vaddr, dma_addr_t dma)
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+{
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+ struct dma_page *page;
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+ unsigned long flags;
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+ unsigned int offset;
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+
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+ page = pool_find_page(pool, dma);
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+ if (!page) {
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+ if (pool->dev)
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+ dev_err(pool->dev,
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+ "dma_pool_free %s, %p/%lx (bad dma)\n",
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+ pool->name, vaddr, (unsigned long)dma);
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+ else
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+ printk(KERN_ERR "dma_pool_free %s, %p/%lx (bad dma)\n",
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+ pool->name, vaddr, (unsigned long)dma);
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+ return;
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+ }
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+
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+ offset = vaddr - page->vaddr;
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+#ifdef CONFIG_DEBUG_SLAB
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+ if ((dma - page->dma) != offset) {
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+ if (pool->dev)
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+ dev_err(pool->dev,
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+ "dma_pool_free %s, %p (bad vaddr)/%Lx\n",
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+ pool->name, vaddr, (unsigned long long)dma);
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+ else
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+ printk(KERN_ERR
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+ "dma_pool_free %s, %p (bad vaddr)/%Lx\n",
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+ pool->name, vaddr, (unsigned long long)dma);
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+ return;
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+ }
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+ {
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+ unsigned int chain = page->offset;
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+ while (chain < pool->allocation) {
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+ if (chain != offset) {
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+ chain = *(int *)(page->vaddr + chain);
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+ continue;
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+ }
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+ if (pool->dev)
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+ dev_err(pool->dev, "dma_pool_free %s, dma %Lx "
|
|
|
+ "already free\n", pool->name,
|
|
|
+ (unsigned long long)dma);
|
|
|
+ else
|
|
|
+ printk(KERN_ERR "dma_pool_free %s, dma %Lx "
|
|
|
+ "already free\n", pool->name,
|
|
|
+ (unsigned long long)dma);
|
|
|
+ return;
|
|
|
+ }
|
|
|
+ }
|
|
|
+ memset(vaddr, POOL_POISON_FREED, pool->size);
|
|
|
+#endif
|
|
|
+
|
|
|
+ spin_lock_irqsave(&pool->lock, flags);
|
|
|
+ page->in_use--;
|
|
|
+ *(int *)vaddr = page->offset;
|
|
|
+ page->offset = offset;
|
|
|
+ if (waitqueue_active(&pool->waitq))
|
|
|
+ wake_up_locked(&pool->waitq);
|
|
|
+ /*
|
|
|
+ * Resist a temptation to do
|
|
|
+ * if (!is_page_busy(page)) pool_free_page(pool, page);
|
|
|
+ * Better have a few empty pages hang around.
|
|
|
+ */
|
|
|
+ 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.
|
|
|
+ */
|
|
|
+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;
|
|
|
+
|
|
|
+ dma_pool_destroy(pool);
|
|
|
+ WARN_ON(devres_destroy(dev, dmam_pool_release, dmam_pool_match, pool));
|
|
|
+}
|
|
|
+EXPORT_SYMBOL(dmam_pool_destroy);
|
Linus Torvalds