1 files changed, 682 insertions, 0 deletions

diff --git a/arch/arm/common/dmabounce.c b/arch/arm/common/dmabounce.c
new file mode 100644
index 0000000..5797b1b
--- /dev/null
+++ b/arch/arm/common/dmabounce.c
@@ -0,0 +1,682 @@
+/*
+ *  arch/arm/common/dmabounce.c
+ *
+ *  Special dma_{map/unmap/dma_sync}_* routines for systems that have
+ *  limited DMA windows. These functions utilize bounce buffers to
+ *  copy data to/from buffers located outside the DMA region. This
+ *  only works for systems in which DMA memory is at the bottom of
+ *  RAM and the remainder of memory is at the top an the DMA memory
+ *  can be marked as ZONE_DMA. Anything beyond that such as discontigous
+ *  DMA windows will require custom implementations that reserve memory
+ *  areas at early bootup.
+ *
+ *  Original version by Brad Parker (brad@heeltoe.com)
+ *  Re-written by Christopher Hoover <ch@murgatroid.com>
+ *  Made generic by Deepak Saxena <dsaxena@plexity.net>
+ *
+ *  Copyright (C) 2002 Hewlett Packard Company.
+ *  Copyright (C) 2004 MontaVista Software, Inc.
+ *
+ *  This program is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU General Public License
+ *  version 2 as published by the Free Software Foundation.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/device.h>
+#include <linux/dma-mapping.h>
+#include <linux/dmapool.h>
+#include <linux/list.h>
+
+#undef DEBUG
+
+#undef STATS
+#ifdef STATS
+#define DO_STATS(X) do { X ; } while (0)
+#else
+#define DO_STATS(X) do { } while (0)
+#endif
+
+/* ************************************************** */
+
+struct safe_buffer {
+	struct list_head node;
+
+	/* original request */
+	void		*ptr;
+	size_t		size;
+	int		direction;
+
+	/* safe buffer info */
+	struct dma_pool *pool;
+	void		*safe;
+	dma_addr_t	safe_dma_addr;
+};
+
+struct dmabounce_device_info {
+	struct list_head node;
+
+	struct device *dev;
+	struct dma_pool *small_buffer_pool;
+	struct dma_pool *large_buffer_pool;
+	struct list_head safe_buffers;
+	unsigned long small_buffer_size, large_buffer_size;
+#ifdef STATS
+	unsigned long sbp_allocs;
+	unsigned long lbp_allocs;
+	unsigned long total_allocs;
+	unsigned long map_op_count;
+	unsigned long bounce_count;
+#endif
+};
+
+static LIST_HEAD(dmabounce_devs);
+
+#ifdef STATS
+static void print_alloc_stats(struct dmabounce_device_info *device_info)
+{
+	printk(KERN_INFO
+		"%s: dmabounce: sbp: %lu, lbp: %lu, other: %lu, total: %lu\n",
+		device_info->dev->bus_id,
+		device_info->sbp_allocs, device_info->lbp_allocs,
+		device_info->total_allocs - device_info->sbp_allocs -
+			device_info->lbp_allocs,
+		device_info->total_allocs);
+}
+#endif
+
+/* find the given device in the dmabounce device list */
+static inline struct dmabounce_device_info *
+find_dmabounce_dev(struct device *dev)
+{
+	struct list_head *entry;
+
+	list_for_each(entry, &dmabounce_devs) {
+		struct dmabounce_device_info *d =
+			list_entry(entry, struct dmabounce_device_info, node);
+
+		if (d->dev == dev)
+			return d;
+	}
+	return NULL;
+}
+
+
+/* allocate a 'safe' buffer and keep track of it */
+static inline struct safe_buffer *
+alloc_safe_buffer(struct dmabounce_device_info *device_info, void *ptr,
+			size_t size, enum dma_data_direction dir)
+{
+	struct safe_buffer *buf;
+	struct dma_pool *pool;
+	struct device *dev = device_info->dev;
+	void *safe;
+	dma_addr_t safe_dma_addr;
+
+	dev_dbg(dev, "%s(ptr=%p, size=%d, dir=%d)\n",
+		__func__, ptr, size, dir);
+
+	DO_STATS ( device_info->total_allocs++ );
+
+	buf = kmalloc(sizeof(struct safe_buffer), GFP_ATOMIC);
+	if (buf == NULL) {
+		dev_warn(dev, "%s: kmalloc failed\n", __func__);
+		return NULL;
+	}
+
+	if (size <= device_info->small_buffer_size) {
+		pool = device_info->small_buffer_pool;
+		safe = dma_pool_alloc(pool, GFP_ATOMIC, &safe_dma_addr);
+
+		DO_STATS ( device_info->sbp_allocs++ );
+	} else if (size <= device_info->large_buffer_size) {
+		pool = device_info->large_buffer_pool;
+		safe = dma_pool_alloc(pool, GFP_ATOMIC, &safe_dma_addr);
+
+		DO_STATS ( device_info->lbp_allocs++ );
+	} else {
+		pool = NULL;
+		safe = dma_alloc_coherent(dev, size, &safe_dma_addr, GFP_ATOMIC);
+	}
+
+	if (safe == NULL) {
+		dev_warn(device_info->dev,
+			"%s: could not alloc dma memory (size=%d)\n",
+		       __func__, size);
+		kfree(buf);
+		return NULL;
+	}
+
+#ifdef STATS
+	if (device_info->total_allocs % 1000 == 0)
+		print_alloc_stats(device_info);
+#endif
+
+	buf->ptr = ptr;
+	buf->size = size;
+	buf->direction = dir;
+	buf->pool = pool;
+	buf->safe = safe;
+	buf->safe_dma_addr = safe_dma_addr;
+
+	list_add(&buf->node, &device_info->safe_buffers);
+
+	return buf;
+}
+
+/* determine if a buffer is from our "safe" pool */
+static inline struct safe_buffer *
+find_safe_buffer(struct dmabounce_device_info *device_info, dma_addr_t safe_dma_addr)
+{
+	struct list_head *entry;
+
+	list_for_each(entry, &device_info->safe_buffers) {
+		struct safe_buffer *b =
+			list_entry(entry, struct safe_buffer, node);
+
+		if (b->safe_dma_addr == safe_dma_addr)
+			return b;
+	}
+
+	return NULL;
+}
+
+static inline void
+free_safe_buffer(struct dmabounce_device_info *device_info, struct safe_buffer *buf)
+{
+	dev_dbg(device_info->dev, "%s(buf=%p)\n", __func__, buf);
+
+	list_del(&buf->node);
+
+	if (buf->pool)
+		dma_pool_free(buf->pool, buf->safe, buf->safe_dma_addr);
+	else
+		dma_free_coherent(device_info->dev, buf->size, buf->safe,
+				    buf->safe_dma_addr);
+
+	kfree(buf);
+}
+
+/* ************************************************** */
+
+#ifdef STATS
+
+static void print_map_stats(struct dmabounce_device_info *device_info)
+{
+	printk(KERN_INFO
+		"%s: dmabounce: map_op_count=%lu, bounce_count=%lu\n",
+		device_info->dev->bus_id,
+		device_info->map_op_count, device_info->bounce_count);
+}
+#endif
+
+static inline dma_addr_t
+map_single(struct device *dev, void *ptr, size_t size,
+		enum dma_data_direction dir)
+{
+	struct dmabounce_device_info *device_info = find_dmabounce_dev(dev);
+	dma_addr_t dma_addr;
+	int needs_bounce = 0;
+
+	if (device_info)
+		DO_STATS ( device_info->map_op_count++ );
+
+	dma_addr = virt_to_dma(dev, ptr);
+
+	if (dev->dma_mask) {
+		unsigned long mask = *dev->dma_mask;
+		unsigned long limit;
+
+		limit = (mask + 1) & ~mask;
+		if (limit && size > limit) {
+			dev_err(dev, "DMA mapping too big (requested %#x "
+				"mask %#Lx)\n", size, *dev->dma_mask);
+			return ~0;
+		}
+
+		/*
+		 * Figure out if we need to bounce from the DMA mask.
+		 */
+		needs_bounce = (dma_addr | (dma_addr + size - 1)) & ~mask;
+	}
+
+	if (device_info && (needs_bounce || dma_needs_bounce(dev, dma_addr, size))) {
+		struct safe_buffer *buf;
+
+		buf = alloc_safe_buffer(device_info, ptr, size, dir);
+		if (buf == 0) {
+			dev_err(dev, "%s: unable to map unsafe buffer %p!\n",
+			       __func__, ptr);
+			return 0;
+		}
+
+		dev_dbg(dev,
+			"%s: unsafe buffer %p (phy=%p) mapped to %p (phy=%p)\n",
+			__func__, buf->ptr, (void *) virt_to_dma(dev, buf->ptr),
+			buf->safe, (void *) buf->safe_dma_addr);
+
+		if ((dir == DMA_TO_DEVICE) ||
+		    (dir == DMA_BIDIRECTIONAL)) {
+			dev_dbg(dev, "%s: copy unsafe %p to safe %p, size %d\n",
+				__func__, ptr, buf->safe, size);
+			memcpy(buf->safe, ptr, size);
+		}
+		consistent_sync(buf->safe, size, dir);
+
+		dma_addr = buf->safe_dma_addr;
+	} else {
+		consistent_sync(ptr, size, dir);
+	}
+
+	return dma_addr;
+}
+
+static inline void
+unmap_single(struct device *dev, dma_addr_t dma_addr, size_t size,
+		enum dma_data_direction dir)
+{
+	struct dmabounce_device_info *device_info = find_dmabounce_dev(dev);
+	struct safe_buffer *buf = NULL;
+
+	/*
+	 * Trying to unmap an invalid mapping
+	 */
+	if (dma_addr == ~0) {
+		dev_err(dev, "Trying to unmap invalid mapping\n");
+		return;
+	}
+
+	if (device_info)
+		buf = find_safe_buffer(device_info, dma_addr);
+
+	if (buf) {
+		BUG_ON(buf->size != size);
+
+		dev_dbg(dev,
+			"%s: unsafe buffer %p (phy=%p) mapped to %p (phy=%p)\n",
+			__func__, buf->ptr, (void *) virt_to_dma(dev, buf->ptr),
+			buf->safe, (void *) buf->safe_dma_addr);
+
+
+		DO_STATS ( device_info->bounce_count++ );
+
+		if ((dir == DMA_FROM_DEVICE) ||
+		    (dir == DMA_BIDIRECTIONAL)) {
+			dev_dbg(dev,
+				"%s: copy back safe %p to unsafe %p size %d\n",
+				__func__, buf->safe, buf->ptr, size);
+			memcpy(buf->ptr, buf->safe, size);
+		}
+		free_safe_buffer(device_info, buf);
+	}
+}
+
+static inline void
+sync_single(struct device *dev, dma_addr_t dma_addr, size_t size,
+		enum dma_data_direction dir)
+{
+	struct dmabounce_device_info *device_info = find_dmabounce_dev(dev);
+	struct safe_buffer *buf = NULL;
+
+	if (device_info)
+		buf = find_safe_buffer(device_info, dma_addr);
+
+	if (buf) {
+		/*
+		 * Both of these checks from original code need to be
+		 * commented out b/c some drivers rely on the following:
+		 *
+		 * 1) Drivers may map a large chunk of memory into DMA space
+		 *    but only sync a small portion of it. Good example is
+		 *    allocating a large buffer, mapping it, and then
+		 *    breaking it up into small descriptors. No point
+		 *    in syncing the whole buffer if you only have to
+		 *    touch one descriptor.
+		 *
+		 * 2) Buffers that are mapped as DMA_BIDIRECTIONAL are
+		 *    usually only synced in one dir at a time.
+		 *
+		 * See drivers/net/eepro100.c for examples of both cases.
+		 *
+		 * -ds
+		 *
+		 * BUG_ON(buf->size != size);
+		 * BUG_ON(buf->direction != dir);
+		 */
+
+		dev_dbg(dev,
+			"%s: unsafe buffer %p (phy=%p) mapped to %p (phy=%p)\n",
+			__func__, buf->ptr, (void *) virt_to_dma(dev, buf->ptr),
+			buf->safe, (void *) buf->safe_dma_addr);
+
+		DO_STATS ( device_info->bounce_count++ );
+
+		switch (dir) {
+		case DMA_FROM_DEVICE:
+			dev_dbg(dev,
+				"%s: copy back safe %p to unsafe %p size %d\n",
+				__func__, buf->safe, buf->ptr, size);
+			memcpy(buf->ptr, buf->safe, size);
+			break;
+		case DMA_TO_DEVICE:
+			dev_dbg(dev,
+				"%s: copy out unsafe %p to safe %p, size %d\n",
+				__func__,buf->ptr, buf->safe, size);
+			memcpy(buf->safe, buf->ptr, size);
+			break;
+		case DMA_BIDIRECTIONAL:
+			BUG();	/* is this allowed?  what does it mean? */
+		default:
+			BUG();
+		}
+		consistent_sync(buf->safe, size, dir);
+	} else {
+		consistent_sync(dma_to_virt(dev, dma_addr), size, dir);
+	}
+}
+
+/* ************************************************** */
+
+/*
+ * see if a buffer address is in an 'unsafe' range.  if it is
+ * allocate a 'safe' buffer and copy the unsafe buffer into it.
+ * substitute the safe buffer for the unsafe one.
+ * (basically move the buffer from an unsafe area to a safe one)
+ */
+dma_addr_t
+dma_map_single(struct device *dev, void *ptr, size_t size,
+		enum dma_data_direction dir)
+{
+	unsigned long flags;
+	dma_addr_t dma_addr;
+
+	dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n",
+		__func__, ptr, size, dir);
+
+	BUG_ON(dir == DMA_NONE);
+
+	local_irq_save(flags);
+
+	dma_addr = map_single(dev, ptr, size, dir);
+
+	local_irq_restore(flags);
+
+	return dma_addr;
+}
+
+/*
+ * see if a mapped address was really a "safe" buffer and if so, copy
+ * the data from the safe buffer back to the unsafe buffer and free up
+ * the safe buffer.  (basically return things back to the way they
+ * should be)
+ */
+
+void
+dma_unmap_single(struct device *dev, dma_addr_t dma_addr, size_t size,
+			enum dma_data_direction dir)
+{
+	unsigned long flags;
+
+	dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n",
+		__func__, (void *) dma_addr, size, dir);
+
+	BUG_ON(dir == DMA_NONE);
+
+	local_irq_save(flags);
+
+	unmap_single(dev, dma_addr, size, dir);
+
+	local_irq_restore(flags);
+}
+
+int
+dma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
+		enum dma_data_direction dir)
+{
+	unsigned long flags;
+	int i;
+
+	dev_dbg(dev, "%s(sg=%p,nents=%d,dir=%x)\n",
+		__func__, sg, nents, dir);
+
+	BUG_ON(dir == DMA_NONE);
+
+	local_irq_save(flags);
+
+	for (i = 0; i < nents; i++, sg++) {
+		struct page *page = sg->page;
+		unsigned int offset = sg->offset;
+		unsigned int length = sg->length;
+		void *ptr = page_address(page) + offset;
+
+		sg->dma_address =
+			map_single(dev, ptr, length, dir);
+	}
+
+	local_irq_restore(flags);
+
+	return nents;
+}
+
+void
+dma_unmap_sg(struct device *dev, struct scatterlist *sg, int nents,
+		enum dma_data_direction dir)
+{
+	unsigned long flags;
+	int i;
+
+	dev_dbg(dev, "%s(sg=%p,nents=%d,dir=%x)\n",
+		__func__, sg, nents, dir);
+
+	BUG_ON(dir == DMA_NONE);
+
+	local_irq_save(flags);
+
+	for (i = 0; i < nents; i++, sg++) {
+		dma_addr_t dma_addr = sg->dma_address;
+		unsigned int length = sg->length;
+
+		unmap_single(dev, dma_addr, length, dir);
+	}
+
+	local_irq_restore(flags);
+}
+
+void
+dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_addr, size_t size,
+				enum dma_data_direction dir)
+{
+	unsigned long flags;
+
+	dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n",
+		__func__, (void *) dma_addr, size, dir);
+
+	local_irq_save(flags);
+
+	sync_single(dev, dma_addr, size, dir);
+
+	local_irq_restore(flags);
+}
+
+void
+dma_sync_single_for_device(struct device *dev, dma_addr_t dma_addr, size_t size,
+				enum dma_data_direction dir)
+{
+	unsigned long flags;
+
+	dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n",
+		__func__, (void *) dma_addr, size, dir);
+
+	local_irq_save(flags);
+
+	sync_single(dev, dma_addr, size, dir);
+
+	local_irq_restore(flags);
+}
+
+void
+dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg, int nents,
+			enum dma_data_direction dir)
+{
+	unsigned long flags;
+	int i;
+
+	dev_dbg(dev, "%s(sg=%p,nents=%d,dir=%x)\n",
+		__func__, sg, nents, dir);
+
+	BUG_ON(dir == DMA_NONE);
+
+	local_irq_save(flags);
+
+	for (i = 0; i < nents; i++, sg++) {
+		dma_addr_t dma_addr = sg->dma_address;
+		unsigned int length = sg->length;
+
+		sync_single(dev, dma_addr, length, dir);
+	}
+
+	local_irq_restore(flags);
+}
+
+void
+dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg, int nents,
+			enum dma_data_direction dir)
+{
+	unsigned long flags;
+	int i;
+
+	dev_dbg(dev, "%s(sg=%p,nents=%d,dir=%x)\n",
+		__func__, sg, nents, dir);
+
+	BUG_ON(dir == DMA_NONE);
+
+	local_irq_save(flags);
+
+	for (i = 0; i < nents; i++, sg++) {
+		dma_addr_t dma_addr = sg->dma_address;
+		unsigned int length = sg->length;
+
+		sync_single(dev, dma_addr, length, dir);
+	}
+
+	local_irq_restore(flags);
+}
+
+int
+dmabounce_register_dev(struct device *dev, unsigned long small_buffer_size,
+			unsigned long large_buffer_size)
+{
+	struct dmabounce_device_info *device_info;
+
+	device_info = kmalloc(sizeof(struct dmabounce_device_info), GFP_ATOMIC);
+	if (!device_info) {
+		printk(KERN_ERR
+			"Could not allocated dmabounce_device_info for %s",
+			dev->bus_id);
+		return -ENOMEM;
+	}
+
+	device_info->small_buffer_pool =
+		dma_pool_create("small_dmabounce_pool",
+				dev,
+				small_buffer_size,
+				0 /* byte alignment */,
+				0 /* no page-crossing issues */);
+	if (!device_info->small_buffer_pool) {
+		printk(KERN_ERR
+			"dmabounce: could not allocate small DMA pool for %s\n",
+			dev->bus_id);
+		kfree(device_info);
+		return -ENOMEM;
+	}
+
+	if (large_buffer_size) {
+		device_info->large_buffer_pool =
+			dma_pool_create("large_dmabounce_pool",
+					dev,
+					large_buffer_size,
+					0 /* byte alignment */,
+					0 /* no page-crossing issues */);
+		if (!device_info->large_buffer_pool) {
+		printk(KERN_ERR
+			"dmabounce: could not allocate large DMA pool for %s\n",
+			dev->bus_id);
+			dma_pool_destroy(device_info->small_buffer_pool);
+
+			return -ENOMEM;
+		}
+	}
+
+	device_info->dev = dev;
+	device_info->small_buffer_size = small_buffer_size;
+	device_info->large_buffer_size = large_buffer_size;
+	INIT_LIST_HEAD(&device_info->safe_buffers);
+
+#ifdef STATS
+	device_info->sbp_allocs = 0;
+	device_info->lbp_allocs = 0;
+	device_info->total_allocs = 0;
+	device_info->map_op_count = 0;
+	device_info->bounce_count = 0;
+#endif
+
+	list_add(&device_info->node, &dmabounce_devs);
+
+	printk(KERN_INFO "dmabounce: registered device %s on %s bus\n",
+		dev->bus_id, dev->bus->name);
+
+	return 0;
+}
+
+void
+dmabounce_unregister_dev(struct device *dev)
+{
+	struct dmabounce_device_info *device_info = find_dmabounce_dev(dev);
+
+	if (!device_info) {
+		printk(KERN_WARNING
+			"%s: Never registered with dmabounce but attempting" \
+			"to unregister!\n", dev->bus_id);
+		return;
+	}
+
+	if (!list_empty(&device_info->safe_buffers)) {
+		printk(KERN_ERR
+			"%s: Removing from dmabounce with pending buffers!\n",
+			dev->bus_id);
+		BUG();
+	}
+
+	if (device_info->small_buffer_pool)
+		dma_pool_destroy(device_info->small_buffer_pool);
+	if (device_info->large_buffer_pool)
+		dma_pool_destroy(device_info->large_buffer_pool);
+
+#ifdef STATS
+	print_alloc_stats(device_info);
+	print_map_stats(device_info);
+#endif
+
+	list_del(&device_info->node);
+
+	kfree(device_info);
+
+	printk(KERN_INFO "dmabounce: device %s on %s bus unregistered\n",
+		dev->bus_id, dev->bus->name);
+}
+
+
+EXPORT_SYMBOL(dma_map_single);
+EXPORT_SYMBOL(dma_unmap_single);
+EXPORT_SYMBOL(dma_map_sg);
+EXPORT_SYMBOL(dma_unmap_sg);
+EXPORT_SYMBOL(dma_sync_single);
+EXPORT_SYMBOL(dma_sync_sg);
+EXPORT_SYMBOL(dmabounce_register_dev);
+EXPORT_SYMBOL(dmabounce_unregister_dev);
+
+MODULE_AUTHOR("Christopher Hoover <ch@hpl.hp.com>, Deepak Saxena <dsaxena@plexity.net>");
+MODULE_DESCRIPTION("Special dma_{map/unmap/dma_sync}_* routines for systems with limited DMA windows");
+MODULE_LICENSE("GPL");