patch-2.4.9 linux/arch/arm/mach-sa1100/pcipool.c

• Lines: 378
• Date: Sun Aug 12 11:13:59 2001
• Orig file: v2.4.8/linux/arch/arm/mach-sa1100/pcipool.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.4.8/linux/arch/arm/mach-sa1100/pcipool.c linux/arch/arm/mach-sa1100/pcipool.c
@@ -0,0 +1,377 @@
+/*
+  NOTE:
+
+  this code was lifted straight out of drivers/pci/pci.c;
+  when compiling for the Intel StrongARM SA-1110/SA-1111 the
+  usb-ohci.c driver needs these routines even when the architecture
+  has no pci bus...
+*/
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/pci.h>
+#include <linux/string.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/bitops.h>
+
+#include <asm/page.h>
+
+#include "pcipool.h"
+
+/*
+ * Pool allocator ... wraps the pci_alloc_consistent 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 pci_pool {	/* the pool */
+	struct list_head	page_list;
+	spinlock_t		lock;
+	size_t			blocks_per_page;
+	size_t			size;
+	int			flags;
+	struct pci_dev		*dev;
+	size_t			allocation;
+	char			name [32];
+	wait_queue_head_t	waitq;
+};
+
+struct pci_page {	/* cacheable header for 'allocation' bytes */
+	struct list_head	page_list;
+	void			*vaddr;
+	dma_addr_t		dma;
+	unsigned long		bitmap [0];
+};
+
+#define	POOL_TIMEOUT_JIFFIES	((100 /* msec */ * HZ) / 1000)
+#define	POOL_POISON_BYTE	0xa7
+
+// #define CONFIG_PCIPOOL_DEBUG
+
+
+/**
+ * pci_pool_create - Creates a pool of pci consistent memory blocks, for dma.
+ * @name: name of pool, for diagnostics
+ * @pdev: pci 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)
+ * @flags: SLAB_* flags (not all are supported).
+ *
+ * Returns a pci allocation pool with the requested characteristics, or
+ * null if one can't be created.  Given one of these pools, pci_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 pci_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 pci_pool *
+pci_pool_create (const char *name, struct pci_dev *pdev,
+	size_t size, size_t align, size_t allocation, int flags)
+{
+	struct pci_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, flags)))
+		return retval;
+
+#ifdef	CONFIG_PCIPOOL_DEBUG
+	flags |= SLAB_POISON;
+#endif
+
+	strncpy (retval->name, name, sizeof retval->name);
+	retval->name [sizeof retval->name - 1] = 0;
+
+	retval->dev = pdev;
+	INIT_LIST_HEAD (&retval->page_list);
+	spin_lock_init (&retval->lock);
+	retval->size = size;
+	retval->flags = flags;
+	retval->allocation = allocation;
+	retval->blocks_per_page = allocation / size;
+	init_waitqueue_head (&retval->waitq);
+
+#ifdef CONFIG_PCIPOOL_DEBUG
+	printk (KERN_DEBUG "pcipool create %s/%s size %d, %d/page (%d alloc)\n",
+		pdev ? pdev->slot_name : NULL, retval->name, size,
+		retval->blocks_per_page, allocation);
+#endif
+
+	return retval;
+}
+
+
+static struct pci_page *
+pool_alloc_page (struct pci_pool *pool, int mem_flags)
+{
+	struct pci_page	*page;
+	int		mapsize;
+
+	mapsize = pool->blocks_per_page;
+	mapsize = (mapsize + BITS_PER_LONG - 1) / BITS_PER_LONG;
+	mapsize *= sizeof (long);
+
+	page = (struct pci_page *) kmalloc (mapsize + sizeof *page, mem_flags);
+	if (!page)
+		return 0;
+	page->vaddr = pci_alloc_consistent (pool->dev,
+				pool->allocation, &page->dma);
+	if (page->vaddr) {
+		memset (page->bitmap, 0xff, mapsize);	// bit set == free
+		if (pool->flags & SLAB_POISON)
+			memset (page->vaddr, POOL_POISON_BYTE, pool->allocation);
+		list_add (&page->page_list, &pool->page_list);
+	} 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 pci_pool *pool, struct pci_page *page)
+{
+	dma_addr_t	dma = page->dma;
+
+	if (pool->flags & SLAB_POISON)
+		memset (page->vaddr, POOL_POISON_BYTE, pool->allocation);
+	pci_free_consistent (pool->dev, pool->allocation, page->vaddr, dma);
+	list_del (&page->page_list);
+	kfree (page);
+}
+
+
+/**
+ * pci_pool_destroy - destroys a pool of pci memory blocks.
+ * @pool: pci pool that will be destroyed
+ *
+ * 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
+pci_pool_destroy (struct pci_pool *pool)
+{
+	unsigned long		flags;
+
+#ifdef CONFIG_PCIPOOL_DEBUG
+	printk (KERN_DEBUG "pcipool destroy %s/%s\n",
+		pool->dev ? pool->dev->slot_name : NULL,
+		pool->name);
+#endif
+
+	spin_lock_irqsave (&pool->lock, flags);
+	while (!list_empty (&pool->page_list)) {
+		struct pci_page		*page;
+		page = list_entry (pool->page_list.next,
+				struct pci_page, page_list);
+		if (is_page_busy (pool->blocks_per_page, page->bitmap)) {
+			printk (KERN_ERR "pci_pool_destroy %s/%s, %p busy\n",
+				pool->dev ? pool->dev->slot_name : 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);
+	}
+	spin_unlock_irqrestore (&pool->lock, flags);
+	kfree (pool);
+}
+
+
+/**
+ * pci_pool_alloc - get a block of consistent memory
+ * @pool: pci 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 *
+pci_pool_alloc (struct pci_pool *pool, int mem_flags, dma_addr_t *handle)
+{
+	unsigned long		flags;
+	struct list_head	*entry;
+	struct pci_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 pci_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, mem_flags))) {
+		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);
+
+			current->state = TASK_RUNNING;
+			remove_wait_queue (&pool->waitq, &wait);
+			goto restart;
+		}
+		retval = 0;
+		goto done;
+	}
+
+	clear_bit (0, &page->bitmap [0]);
+	offset = 0;
+ready:
+	retval = offset + page->vaddr;
+	*handle = offset + page->dma;
+done:
+	spin_unlock_irqrestore (&pool->lock, flags);
+	return retval;
+}
+
+
+static struct pci_page *
+pool_find_page (struct pci_pool *pool, dma_addr_t dma)
+{
+	unsigned long		flags;
+	struct list_head	*entry;
+	struct pci_page		*page;
+
+	spin_lock_irqsave (&pool->lock, flags);
+	list_for_each (entry, &pool->page_list) {
+		page = list_entry (entry, struct pci_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;
+}
+
+
+/**
+ * pci_pool_free - put block back into pci pool
+ * @pool: the pci 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
+pci_pool_free (struct pci_pool *pool, void *vaddr, dma_addr_t dma)
+{
+	struct pci_page		*page;
+	unsigned long		flags;
+	int			map, block;
+
+	if ((page = pool_find_page (pool, dma)) == 0) {
+		printk (KERN_ERR "pci_pool_free %s/%s, %p/%x (bad dma)\n",
+			pool->dev ? pool->dev->slot_name : NULL,
+			pool->name, vaddr, dma);
+		return;
+	}
+#ifdef	CONFIG_PCIPOOL_DEBUG
+	if (((dma - page->dma) + (void *)page->vaddr) != vaddr) {
+		printk (KERN_ERR "pci_pool_free %s/%s, %p (bad vaddr)/%x\n",
+			pool->dev ? pool->dev->slot_name : NULL,
+			pool->name, vaddr, dma);
+		return;
+	}
+#endif
+
+	block = dma - page->dma;
+	block /= pool->size;
+	map = block / BITS_PER_LONG;
+	block %= BITS_PER_LONG;
+
+#ifdef	CONFIG_PCIPOOL_DEBUG
+	if (page->bitmap [map] & (1UL << block)) {
+		printk (KERN_ERR "pci_pool_free %s/%s, dma %x already free\n",
+			pool->dev ? pool->dev->slot_name : NULL,
+			pool->name, dma);
+		return;
+	}
+#endif
+	if (pool->flags & SLAB_POISON)
+		memset (vaddr, POOL_POISON_BYTE, pool->size);
+
+	spin_lock_irqsave (&pool->lock, flags);
+	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 (pci_pool_create);
+EXPORT_SYMBOL (pci_pool_destroy);
+EXPORT_SYMBOL (pci_pool_alloc);
+EXPORT_SYMBOL (pci_pool_free);
+