linux/arch/arm/common/dmabounce.c

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/*
* 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, the remainder of memory is at the top and the DMA memory
* can be marked as ZONE_DMA. Anything beyond that such as discontiguous
* 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>
#include <linux/scatterlist.h>
#include <asm/cacheflush.h>
#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 dmabounce_pool *pool;
void *safe;
dma_addr_t safe_dma_addr;
};
struct dmabounce_pool {
unsigned long size;
struct dma_pool *pool;
#ifdef STATS
unsigned long allocs;
#endif
};
struct dmabounce_device_info {
struct device *dev;
struct list_head safe_buffers;
#ifdef STATS
unsigned long total_allocs;
unsigned long map_op_count;
unsigned long bounce_count;
int attr_res;
#endif
struct dmabounce_pool small;
struct dmabounce_pool large;
rwlock_t lock;
};
#ifdef STATS
static ssize_t dmabounce_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct dmabounce_device_info *device_info = dev->archdata.dmabounce;
return sprintf(buf, "%lu %lu %lu %lu %lu %lu\n",
device_info->small.allocs,
device_info->large.allocs,
device_info->total_allocs - device_info->small.allocs -
device_info->large.allocs,
device_info->total_allocs,
device_info->map_op_count,
device_info->bounce_count);
}
static DEVICE_ATTR(dmabounce_stats, 0400, dmabounce_show, NULL);
#endif
/* 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 dmabounce_pool *pool;
struct device *dev = device_info->dev;
unsigned long flags;
dev_dbg(dev, "%s(ptr=%p, size=%d, dir=%d)\n",
__func__, ptr, size, dir);
if (size <= device_info->small.size) {
pool = &device_info->small;
} else if (size <= device_info->large.size) {
pool = &device_info->large;
} else {
pool = NULL;
}
buf = kmalloc(sizeof(struct safe_buffer), GFP_ATOMIC);
if (buf == NULL) {
dev_warn(dev, "%s: kmalloc failed\n", __func__);
return NULL;
}
buf->ptr = ptr;
buf->size = size;
buf->direction = dir;
buf->pool = pool;
if (pool) {
buf->safe = dma_pool_alloc(pool->pool, GFP_ATOMIC,
&buf->safe_dma_addr);
} else {
buf->safe = dma_alloc_coherent(dev, size, &buf->safe_dma_addr,
GFP_ATOMIC);
}
if (buf->safe == NULL) {
dev_warn(dev,
"%s: could not alloc dma memory (size=%d)\n",
__func__, size);
kfree(buf);
return NULL;
}
#ifdef STATS
if (pool)
pool->allocs++;
device_info->total_allocs++;
#endif
write_lock_irqsave(&device_info->lock, flags);
list_add(&buf->node, &device_info->safe_buffers);
write_unlock_irqrestore(&device_info->lock, flags);
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 safe_buffer *b, *rb = NULL;
unsigned long flags;
read_lock_irqsave(&device_info->lock, flags);
list_for_each_entry(b, &device_info->safe_buffers, node)
if (b->safe_dma_addr == safe_dma_addr) {
rb = b;
break;
}
read_unlock_irqrestore(&device_info->lock, flags);
return rb;
}
static inline void
free_safe_buffer(struct dmabounce_device_info *device_info, struct safe_buffer *buf)
{
unsigned long flags;
dev_dbg(device_info->dev, "%s(buf=%p)\n", __func__, buf);
write_lock_irqsave(&device_info->lock, flags);
list_del(&buf->node);
write_unlock_irqrestore(&device_info->lock, flags);
if (buf->pool)
dma_pool_free(buf->pool->pool, buf->safe, buf->safe_dma_addr);
else
dma_free_coherent(device_info->dev, buf->size, buf->safe,
buf->safe_dma_addr);
kfree(buf);
}
/* ************************************************** */
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 = dev->archdata.dmabounce;
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 (dma=%#x) mapped to %p (dma=%#x)\n",
__func__, buf->ptr, virt_to_dma(dev, buf->ptr),
buf->safe, 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);
}
ptr = buf->safe;
dma_addr = buf->safe_dma_addr;
} else {
/*
* We don't need to sync the DMA buffer since
* it was allocated via the coherent allocators.
*/
dma_cache_maint(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 = dev->archdata.dmabounce;
struct safe_buffer *buf = NULL;
/*
* Trying to unmap an invalid mapping
*/
dma-mapping: add the device argument to dma_mapping_error() Add per-device dma_mapping_ops support for CONFIG_X86_64 as POWER architecture does: This enables us to cleanly fix the Calgary IOMMU issue that some devices are not behind the IOMMU (http://lkml.org/lkml/2008/5/8/423). I think that per-device dma_mapping_ops support would be also helpful for KVM people to support PCI passthrough but Andi thinks that this makes it difficult to support the PCI passthrough (see the above thread). So I CC'ed this to KVM camp. Comments are appreciated. A pointer to dma_mapping_ops to struct dev_archdata is added. If the pointer is non NULL, DMA operations in asm/dma-mapping.h use it. If it's NULL, the system-wide dma_ops pointer is used as before. If it's useful for KVM people, I plan to implement a mechanism to register a hook called when a new pci (or dma capable) device is created (it works with hot plugging). It enables IOMMUs to set up an appropriate dma_mapping_ops per device. The major obstacle is that dma_mapping_error doesn't take a pointer to the device unlike other DMA operations. So x86 can't have dma_mapping_ops per device. Note all the POWER IOMMUs use the same dma_mapping_error function so this is not a problem for POWER but x86 IOMMUs use different dma_mapping_error functions. The first patch adds the device argument to dma_mapping_error. The patch is trivial but large since it touches lots of drivers and dma-mapping.h in all the architecture. This patch: dma_mapping_error() doesn't take a pointer to the device unlike other DMA operations. So we can't have dma_mapping_ops per device. Note that POWER already has dma_mapping_ops per device but all the POWER IOMMUs use the same dma_mapping_error function. x86 IOMMUs use device argument. [akpm@linux-foundation.org: fix sge] [akpm@linux-foundation.org: fix svc_rdma] [akpm@linux-foundation.org: build fix] [akpm@linux-foundation.org: fix bnx2x] [akpm@linux-foundation.org: fix s2io] [akpm@linux-foundation.org: fix pasemi_mac] [akpm@linux-foundation.org: fix sdhci] [akpm@linux-foundation.org: build fix] [akpm@linux-foundation.org: fix sparc] [akpm@linux-foundation.org: fix ibmvscsi] Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Cc: Muli Ben-Yehuda <muli@il.ibm.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: Avi Kivity <avi@qumranet.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-26 02:44:49 +00:00
if (dma_mapping_error(dev, dma_addr)) {
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 (dma=%#x) mapped to %p (dma=%#x)\n",
__func__, buf->ptr, virt_to_dma(dev, buf->ptr),
buf->safe, buf->safe_dma_addr);
DO_STATS ( device_info->bounce_count++ );
if (dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL) {
void *ptr = buf->ptr;
dev_dbg(dev,
"%s: copy back safe %p to unsafe %p size %d\n",
__func__, buf->safe, ptr, size);
memcpy(ptr, buf->safe, size);
/*
* DMA buffers must have the same cache properties
* as if they were really used for DMA - which means
* data must be written back to RAM. Note that
* we don't use dmac_flush_range() here for the
* bidirectional case because we know the cache
* lines will be coherent with the data written.
*/
dmac_clean_range(ptr, ptr + size);
outer_clean_range(__pa(ptr), __pa(ptr) + size);
}
free_safe_buffer(device_info, buf);
}
}
static int sync_single(struct device *dev, dma_addr_t dma_addr, size_t size,
enum dma_data_direction dir)
{
struct dmabounce_device_info *device_info = dev->archdata.dmabounce;
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 (dma=%#x) mapped to %p (dma=%#x)\n",
__func__, buf->ptr, virt_to_dma(dev, buf->ptr),
buf->safe, 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();
}
/*
* No need to sync the safe buffer - it was allocated
* via the coherent allocators.
*/
return 0;
} else {
return 1;
}
}
/* ************************************************** */
/*
* 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)
{
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);
dma_addr = map_single(dev, ptr, size, dir);
return dma_addr;
}
dma_addr_t dma_map_page(struct device *dev, struct page *page,
unsigned long offset, size_t size,
enum dma_data_direction dir)
{
dev_dbg(dev, "%s(page=%p,off=%#lx,size=%zx,dir=%x)\n",
__func__, page, offset, size, dir);
BUG_ON(dir == DMA_NONE);
return map_single(dev, page_address(page) + offset, size, dir);
}
EXPORT_SYMBOL(dma_map_page);
/*
* 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)
{
dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n",
__func__, (void *) dma_addr, size, dir);
BUG_ON(dir == DMA_NONE);
unmap_single(dev, dma_addr, size, dir);
}
int dmabounce_sync_for_cpu(struct device *dev, dma_addr_t addr,
unsigned long off, size_t sz, enum dma_data_direction dir)
{
dev_dbg(dev, "%s(dma=%#lx,off=%#lx,sz=%zx,dir=%x)\n",
__func__, addr, off, sz, dir);
return sync_single(dev, addr, off + sz, dir);
}
EXPORT_SYMBOL(dmabounce_sync_for_cpu);
int dmabounce_sync_for_device(struct device *dev, dma_addr_t addr,
unsigned long off, size_t sz, enum dma_data_direction dir)
{
dev_dbg(dev, "%s(dma=%#lx,off=%#lx,sz=%zx,dir=%x)\n",
__func__, addr, off, sz, dir);
return sync_single(dev, addr, off + sz, dir);
}
EXPORT_SYMBOL(dmabounce_sync_for_device);
static int
dmabounce_init_pool(struct dmabounce_pool *pool, struct device *dev, const char *name,
unsigned long size)
{
pool->size = size;
DO_STATS(pool->allocs = 0);
pool->pool = dma_pool_create(name, dev, size,
0 /* byte alignment */,
0 /* no page-crossing issues */);
return pool->pool ? 0 : -ENOMEM;
}
int
dmabounce_register_dev(struct device *dev, unsigned long small_buffer_size,
unsigned long large_buffer_size)
{
struct dmabounce_device_info *device_info;
int ret;
device_info = kmalloc(sizeof(struct dmabounce_device_info), GFP_ATOMIC);
if (!device_info) {
dev_err(dev,
"Could not allocated dmabounce_device_info\n");
return -ENOMEM;
}
ret = dmabounce_init_pool(&device_info->small, dev,
"small_dmabounce_pool", small_buffer_size);
if (ret) {
dev_err(dev,
"dmabounce: could not allocate DMA pool for %ld byte objects\n",
small_buffer_size);
goto err_free;
}
if (large_buffer_size) {
ret = dmabounce_init_pool(&device_info->large, dev,
"large_dmabounce_pool",
large_buffer_size);
if (ret) {
dev_err(dev,
"dmabounce: could not allocate DMA pool for %ld byte objects\n",
large_buffer_size);
goto err_destroy;
}
}
device_info->dev = dev;
INIT_LIST_HEAD(&device_info->safe_buffers);
rwlock_init(&device_info->lock);
#ifdef STATS
device_info->total_allocs = 0;
device_info->map_op_count = 0;
device_info->bounce_count = 0;
device_info->attr_res = device_create_file(dev, &dev_attr_dmabounce_stats);
#endif
dev->archdata.dmabounce = device_info;
dev_info(dev, "dmabounce: registered device\n");
return 0;
err_destroy:
dma_pool_destroy(device_info->small.pool);
err_free:
kfree(device_info);
return ret;
}
void
dmabounce_unregister_dev(struct device *dev)
{
struct dmabounce_device_info *device_info = dev->archdata.dmabounce;
dev->archdata.dmabounce = NULL;
if (!device_info) {
dev_warn(dev,
"Never registered with dmabounce but attempting"
"to unregister!\n");
return;
}
if (!list_empty(&device_info->safe_buffers)) {
dev_err(dev,
"Removing from dmabounce with pending buffers!\n");
BUG();
}
if (device_info->small.pool)
dma_pool_destroy(device_info->small.pool);
if (device_info->large.pool)
dma_pool_destroy(device_info->large.pool);
#ifdef STATS
if (device_info->attr_res == 0)
device_remove_file(dev, &dev_attr_dmabounce_stats);
#endif
kfree(device_info);
dev_info(dev, "dmabounce: device unregistered\n");
}
EXPORT_SYMBOL(dma_map_single);
EXPORT_SYMBOL(dma_unmap_single);
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");