1 files changed, 481 insertions, 0 deletions

diff --git a/mm/dmapool.c b/mm/dmapool.c
new file mode 100644
index 000000000000..b5034dc72a05
--- /dev/null
+++ b/mm/dmapool.c
@@ -0,0 +1,481 @@
+
+#include <linux/device.h>
+#include <linux/mm.h>
+#include <asm/io.h>             /* Needed for i386 to build */
+#include <linux/dma-mapping.h>
+#include <linux/dmapool.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/poison.h>
+#include <linux/sched.h>
+
+/*
+ * Pool allocator ... wraps the dma_alloc_coherent page allocator, so
+ * small blocks are easily used by drivers for bus mastering controllers.
+ * This should probably be sharing the guts of the slab allocator.
+ */
+
+struct dma_pool {       /* the pool */
+        struct list_head        page_list;
+        spinlock_t              lock;
+        size_t                  blocks_per_page;
+        size_t                  size;
+        struct device           *dev;
+        size_t                  allocation;
+        char                    name [32];
+        wait_queue_head_t       waitq;
+        struct list_head        pools;
+};
+
+struct dma_page {       /* cacheable header for 'allocation' bytes */
+        struct list_head        page_list;
+        void                    *vaddr;
+        dma_addr_t              dma;
+        unsigned                in_use;
+        unsigned long           bitmap [0];
+};
+
+#define POOL_TIMEOUT_JIFFIES    ((100 /* msec */ * HZ) / 1000)
+
+static DEFINE_MUTEX (pools_lock);
+
+static ssize_t
+show_pools (struct device *dev, struct device_attribute *attr, char *buf)
+{
+        unsigned temp;
+        unsigned size;
+        char *next;
+        struct dma_page *page;
+        struct dma_pool *pool;
+
+        next = buf;
+        size = PAGE_SIZE;
+
+        temp = scnprintf(next, size, "poolinfo - 0.1\n");
+        size -= temp;
+        next += temp;
+
+        mutex_lock(&pools_lock);
+        list_for_each_entry(pool, &dev->dma_pools, pools) {
+                unsigned pages = 0;
+                unsigned blocks = 0;
+
+                list_for_each_entry(page, &pool->page_list, page_list) {
+                        pages++;
+                        blocks += page->in_use;
+                }
+
+                /* per-pool info, no real statistics yet */
+                temp = scnprintf(next, size, "%-16s %4u %4Zu %4Zu %2u\n",
+                                pool->name,
+                                blocks, pages * pool->blocks_per_page,
+                                pool->size, pages);
+                size -= temp;
+                next += temp;
+        }
+        mutex_unlock(&pools_lock);
+
+        return PAGE_SIZE - size;
+}
+static DEVICE_ATTR (pools, S_IRUGO, show_pools, NULL);
+
+/**
+ * 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
+ * @allocation: returned blocks won't cross this boundary (or zero)
+ * Context: !in_interrupt()
+ *
+ * Returns a dma allocation pool with the requested characteristics, or
+ * null if one can't be created.  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 allocation 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.
+ */
+struct dma_pool *
+dma_pool_create (const char *name, struct device *dev,
+        size_t size, size_t align, size_t allocation)
+{
+        struct dma_pool         *retval;
+
+        if (align == 0)
+                align = 1;
+        if (size == 0)
+                return NULL;
+        else if (size < align)
+                size = align;
+        else if ((size % align) != 0) {
+                size += align + 1;
+                size &= ~(align - 1);
+        }
+
+        if (allocation == 0) {
+                if (PAGE_SIZE < size)
+                        allocation = size;
+                else
+                        allocation = PAGE_SIZE;
+                // FIXME: round up for less fragmentation
+        } else if (allocation < size)
+                return NULL;
+
+        if (!(retval = kmalloc_node (sizeof *retval, GFP_KERNEL, dev_to_node(dev))))
+                return retval;
+
+        strlcpy (retval->name, name, sizeof retval->name);
+
+        retval->dev = dev;
+
+        INIT_LIST_HEAD (&retval->page_list);
+        spin_lock_init (&retval->lock);
+        retval->size = size;
+        retval->allocation = allocation;
+        retval->blocks_per_page = allocation / size;
+        init_waitqueue_head (&retval->waitq);
+
+        if (dev) {
+                int ret;
+
+                mutex_lock(&pools_lock);
+                if (list_empty (&dev->dma_pools))
+                        ret = device_create_file (dev, &dev_attr_pools);
+                else
+                        ret = 0;
+                /* note:  not currently insisting "name" be unique */
+                if (!ret)
+                        list_add (&retval->pools, &dev->dma_pools);
+                else {
+                        kfree(retval);
+                        retval = NULL;
+                }
+                mutex_unlock(&pools_lock);
+        } else
+                INIT_LIST_HEAD (&retval->pools);
+
+        return retval;
+}
+
+
+static struct dma_page *
+pool_alloc_page (struct dma_pool *pool, gfp_t mem_flags)
+{
+        struct dma_page *page;
+        int             mapsize;
+
+        mapsize = pool->blocks_per_page;
+        mapsize = (mapsize + BITS_PER_LONG - 1) / BITS_PER_LONG;
+        mapsize *= sizeof (long);
+
+        page = kmalloc(mapsize + sizeof *page, mem_flags);
+        if (!page)
+                return NULL;
+        page->vaddr = dma_alloc_coherent (pool->dev,
+                                            pool->allocation,
+                                            &page->dma,
+                                            mem_flags);
+        if (page->vaddr) {
+                memset (page->bitmap, 0xff, mapsize);   // bit set == free
+#ifdef  CONFIG_DEBUG_SLAB
+                memset (page->vaddr, POOL_POISON_FREED, pool->allocation);
+#endif
+                list_add (&page->page_list, &pool->page_list);
+                page->in_use = 0;
+        } else {
+                kfree (page);
+                page = NULL;
+        }
+        return page;
+}
+
+
+static inline int
+is_page_busy (int blocks, unsigned long *bitmap)
+{
+        while (blocks > 0) {
+                if (*bitmap++ != ~0UL)
+                        return 1;
+                blocks -= BITS_PER_LONG;
+        }
+        return 0;
+}
+
+static void
+pool_free_page (struct dma_pool *pool, struct dma_page *page)
+{
+        dma_addr_t      dma = page->dma;
+
+#ifdef  CONFIG_DEBUG_SLAB
+        memset (page->vaddr, POOL_POISON_FREED, pool->allocation);
+#endif
+        dma_free_coherent (pool->dev, pool->allocation, page->vaddr, dma);
+        list_del (&page->page_list);
+        kfree (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)
+{
+        mutex_lock(&pools_lock);
+        list_del (&pool->pools);
+        if (pool->dev && list_empty (&pool->dev->dma_pools))
+                device_remove_file (pool->dev, &dev_attr_pools);
+        mutex_unlock(&pools_lock);
+
+        while (!list_empty (&pool->page_list)) {
+                struct dma_page         *page;
+                page = list_entry (pool->page_list.next,
+                                struct dma_page, page_list);
+                if (is_page_busy (pool->blocks_per_page, page->bitmap)) {
+                        if (pool->dev)
+                                dev_err(pool->dev, "dma_pool_destroy %s, %p busy\n",
+                                        pool->name, page->vaddr);
+                        else
+                                printk (KERN_ERR "dma_pool_destroy %s, %p busy\n",
+                                        pool->name, page->vaddr);
+                        /* leak the still-in-use consistent memory */
+                        list_del (&page->page_list);
+                        kfree (page);
+                } else
+                        pool_free_page (pool, page);
+        }
+
+        kfree (pool);
+}
+
+
+/**
+ * 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
+ *
+ * This returns 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)
+{
+        unsigned long           flags;
+        struct dma_page         *page;
+        int                     map, block;
+        size_t                  offset;
+        void                    *retval;
+
+restart:
+        spin_lock_irqsave (&pool->lock, flags);
+        list_for_each_entry(page, &pool->page_list, page_list) {
+                int             i;
+                /* only cachable accesses here ... */
+                for (map = 0, i = 0;
+                                i < pool->blocks_per_page;
+                                i += BITS_PER_LONG, map++) {
+                        if (page->bitmap [map] == 0)
+                                continue;
+                        block = ffz (~ page->bitmap [map]);
+                        if ((i + block) < pool->blocks_per_page) {
+                                clear_bit (block, &page->bitmap [map]);
+                                offset = (BITS_PER_LONG * map) + block;
+                                offset *= pool->size;
+                                goto ready;
+                        }
+                }
+        }
+        if (!(page = pool_alloc_page (pool, GFP_ATOMIC))) {
+                if (mem_flags & __GFP_WAIT) {
+                        DECLARE_WAITQUEUE (wait, current);
+
+                        __set_current_state(TASK_INTERRUPTIBLE);
+                        add_wait_queue (&pool->waitq, &wait);
+                        spin_unlock_irqrestore (&pool->lock, flags);
+
+                        schedule_timeout (POOL_TIMEOUT_JIFFIES);
+
+                        remove_wait_queue (&pool->waitq, &wait);
+                        goto restart;
+                }
+                retval = NULL;
+                goto done;
+        }
+
+        clear_bit (0, &page->bitmap [0]);
+        offset = 0;
+ready:
+        page->in_use++;
+        retval = offset + page->vaddr;
+        *handle = offset + page->dma;
+#ifdef  CONFIG_DEBUG_SLAB
+        memset (retval, POOL_POISON_ALLOCATED, pool->size);
+#endif
+done:
+        spin_unlock_irqrestore (&pool->lock, flags);
+        return retval;
+}
+
+
+static struct dma_page *
+pool_find_page (struct dma_pool *pool, dma_addr_t dma)
+{
+        unsigned long           flags;
+        struct dma_page         *page;
+
+        spin_lock_irqsave (&pool->lock, flags);
+        list_for_each_entry(page, &pool->page_list, page_list) {
+                if (dma < page->dma)
+                        continue;
+                if (dma < (page->dma + pool->allocation))
+                        goto done;
+        }
+        page = NULL;
+done:
+        spin_unlock_irqrestore (&pool->lock, flags);
+        return page;
+}
+
+
+/**
+ * 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_page         *page;
+        unsigned long           flags;
+        int                     map, block;
+
+        if ((page = pool_find_page(pool, dma)) == NULL) {
+                if (pool->dev)
+                        dev_err(pool->dev, "dma_pool_free %s, %p/%lx (bad dma)\n",
+                                pool->name, vaddr, (unsigned long) dma);
+                else
+                        printk (KERN_ERR "dma_pool_free %s, %p/%lx (bad dma)\n",
+                                pool->name, vaddr, (unsigned long) dma);
+                return;
+        }
+
+        block = dma - page->dma;
+        block /= pool->size;
+        map = block / BITS_PER_LONG;
+        block %= BITS_PER_LONG;
+
+#ifdef  CONFIG_DEBUG_SLAB
+        if (((dma - page->dma) + (void *)page->vaddr) != vaddr) {
+                if (pool->dev)
+                        dev_err(pool->dev, "dma_pool_free %s, %p (bad vaddr)/%Lx\n",
+                                pool->name, vaddr, (unsigned long long) dma);
+                else
+                        printk (KERN_ERR "dma_pool_free %s, %p (bad vaddr)/%Lx\n",
+                                pool->name, vaddr, (unsigned long long) dma);
+                return;
+        }
+        if (page->bitmap [map] & (1UL << block)) {
+                if (pool->dev)
+                        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--;
+        set_bit (block, &page->bitmap [map]);
+        if (waitqueue_active (&pool->waitq))
+                wake_up (&pool->waitq);
+        /*
+         * Resist a temptation to do
+         *    if (!is_page_busy(bpp, page->bitmap)) pool_free_page(pool, page);
+         * Better have a few empty pages hang around.
+         */
+        spin_unlock_irqrestore (&pool->lock, flags);
+}
+
+/*
+ * 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;
+}
+
+/**
+ * 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 (dma_pool_create);
+EXPORT_SYMBOL (dma_pool_destroy);
+EXPORT_SYMBOL (dma_pool_alloc);
+EXPORT_SYMBOL (dma_pool_free);
+EXPORT_SYMBOL (dmam_pool_create);
+EXPORT_SYMBOL (dmam_pool_destroy);