[PATCH 1/3] Replace pci_pool with generic dma_pool
From: Deepak Saxena (dsaxena_at_plexity.net)
Date: 01/31/04
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Date: Fri, 30 Jan 2004 17:37:31 -0700 To: torvalds@osdl.org, akpm@osdl.org
- Add dmapool.c to drivers/base
- Initialize struct device.dma_pools in device_initialize()
diff -Nru a/drivers/base/Makefile b/drivers/base/Makefile
--- a/drivers/base/Makefile Fri Jan 30 12:20:30 2004
+++ b/drivers/base/Makefile Fri Jan 30 12:20:30 2004
@@ -2,7 +2,7 @@
obj-y := core.o sys.o interface.o bus.o \
driver.o class.o class_simple.o platform.o \
- cpu.o firmware.o init.o map.o
+ cpu.o firmware.o init.o map.o dmapool.o
obj-y += power/
obj-$(CONFIG_FW_LOADER) += firmware_class.o
obj-$(CONFIG_NUMA) += node.o memblk.o
diff -Nru a/drivers/base/core.c b/drivers/base/core.c
--- a/drivers/base/core.c Fri Jan 30 12:20:30 2004
+++ b/drivers/base/core.c Fri Jan 30 12:20:30 2004
@@ -197,6 +197,7 @@
INIT_LIST_HEAD(&dev->children);
INIT_LIST_HEAD(&dev->driver_list);
INIT_LIST_HEAD(&dev->bus_list);
+ INIT_LIST_HEAD(&dev->dma_pools);
}
/**
diff -Nru a/drivers/base/dmapool.c b/drivers/base/dmapool.c
--- /dev/null Wed Dec 31 16:00:00 1969
+++ b/drivers/base/dmapool.c Fri Jan 30 12:20:30 2004
@@ -0,0 +1,409 @@
+
+#include <linux/device.h>
+#include <linux/mm.h>
+#include <asm/io.h> /* Needed for i386 to build */
+#include <asm/scatterlist.h> /* Needed for i386 to build */
+#include <linux/dma-mapping.h>
+#include <linux/dmapool.h>
+#include <linux/slab.h>
+#include <linux/module.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)
+#define POOL_POISON_FREED 0xa7 /* !inuse */
+#define POOL_POISON_ALLOCATED 0xa9 /* !initted */
+
+static DECLARE_MUTEX (pools_lock);
+
+static ssize_t
+show_pools (struct device *dev, char *buf)
+{
+ unsigned temp, size;
+ char *next;
+ struct list_head *i, *j;
+
+ next = buf;
+ size = PAGE_SIZE;
+
+ temp = snprintf (next, size, "poolinfo - 0.1\n");
+ size -= temp;
+ next += temp;
+
+ down (&pools_lock);
+ list_for_each (i, &dev->dma_pools) {
+ struct dma_pool *pool;
+ unsigned pages = 0, blocks = 0;
+
+ pool = list_entry (i, struct dma_pool, pools);
+
+ list_for_each (j, &pool->page_list) {
+ struct dma_page *page;
+
+ page = list_entry (j, struct dma_page, page_list);
+ pages++;
+ blocks += page->in_use;
+ }
+
+ /* per-pool info, no real statistics yet */
+ temp = snprintf (next, size, "%-16s %4u %4Zu %4Zu %2u\n",
+ pool->name,
+ blocks, pages * pool->blocks_per_page,
+ pool->size, pages);
+ size -= temp;
+ next += temp;
+ }
+ up (&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 0;
+ 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 0;
+
+ if (!(retval = kmalloc (sizeof *retval, SLAB_KERNEL)))
+ 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) {
+ down (&pools_lock);
+ if (list_empty (&dev->dma_pools))
+ device_create_file (dev, &dev_attr_pools);
+ /* note: not currently insisting "name" be unique */
+ list_add (&retval->pools, &dev->dma_pools);
+ up (&pools_lock);
+ } else
+ INIT_LIST_HEAD (&retval->pools);
+
+ return retval;
+}
+
+
+static struct dma_page *
+pool_alloc_page (struct dma_pool *pool, int 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 = (struct dma_page *) kmalloc (mapsize + sizeof *page, mem_flags);
+ if (!page)
+ return 0;
+ 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 = 0;
+ }
+ 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)
+{
+ down (&pools_lock);
+ list_del (&pool->pools);
+ if (pool->dev && list_empty (&pool->dev->dma_pools))
+ device_remove_file (pool->dev, &dev_attr_pools);
+ up (&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)) {
+ printk (KERN_ERR "dma_pool_destroy %s/%s, %p busy\n",
+ pool->dev ? pool->dev->bus_id : NULL,
+ 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: SLAB_KERNEL or SLAB_ATOMIC
+ * @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, int mem_flags, dma_addr_t *handle)
+{
+ unsigned long flags;
+ struct list_head *entry;
+ struct dma_page *page;
+ int map, block;
+ size_t offset;
+ void *retval;
+
+restart:
+ spin_lock_irqsave (&pool->lock, flags);
+ list_for_each (entry, &pool->page_list) {
+ int i;
+ page = list_entry (entry, struct dma_page, page_list);
+ /* 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, SLAB_ATOMIC))) {
+ if (mem_flags == SLAB_KERNEL) {
+ DECLARE_WAITQUEUE (wait, current);
+
+ 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 = 0;
+ 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 list_head *entry;
+ struct dma_page *page;
+
+ spin_lock_irqsave (&pool->lock, flags);
+ list_for_each (entry, &pool->page_list) {
+ page = list_entry (entry, struct dma_page, page_list);
+ if (dma < page->dma)
+ continue;
+ if (dma < (page->dma + pool->allocation))
+ goto done;
+ }
+ page = 0;
+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)) == 0) {
+ printk (KERN_ERR "dma_pool_free %s/%s, %p/%lx (bad dma)\n",
+ pool->dev ? pool->dev->bus_id : NULL,
+ 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) {
+ printk (KERN_ERR "dma_pool_free %s/%s, %p (bad vaddr)/%Lx\n",
+ pool->dev ? pool->dev->bus_id : NULL,
+ pool->name, vaddr, (unsigned long long) dma);
+ return;
+ }
+ if (page->bitmap [map] & (1UL << block)) {
+ printk (KERN_ERR "dma_pool_free %s/%s, dma %Lx already free\n",
+ pool->dev ? pool->dev->bus_id : NULL,
+ 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);
+ * it is not interrupt safe. Better have empty pages hang around.
+ */
+ spin_unlock_irqrestore (&pool->lock, flags);
+}
+
+
+EXPORT_SYMBOL (dma_pool_create);
+EXPORT_SYMBOL (dma_pool_destroy);
+EXPORT_SYMBOL (dma_pool_alloc);
+EXPORT_SYMBOL (dma_pool_free);
-- Deepak Saxena - dsaxena@plexity.net - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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