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-rw-r--r--arch/arm/common/dmabounce.c682
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 000000000000..5797b1b100a1
--- /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");