![Guennadi Liakhovetski](/assets/img/avatar_default.png)
dma_declare_coherent_memory() allocates a bitmap 1 bit per page, it calculates the bitmap size based on size of long, but allocates bytes... Thanks to James Bottomley for clarifications and corrections. Signed-off-by: G. Liakhovetski <g.liakhovetski@gmx.de> Acked-by: James Bottomley <James.Bottomley@SteelEye.com> Cc: Mikael Starvik <starvik@axis.com> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
151 lines
3.6 KiB
C
151 lines
3.6 KiB
C
/*
|
|
* Dynamic DMA mapping support.
|
|
*
|
|
* On i386 there is no hardware dynamic DMA address translation,
|
|
* so consistent alloc/free are merely page allocation/freeing.
|
|
* The rest of the dynamic DMA mapping interface is implemented
|
|
* in asm/pci.h.
|
|
*/
|
|
|
|
#include <linux/types.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/string.h>
|
|
#include <linux/pci.h>
|
|
#include <linux/module.h>
|
|
#include <asm/io.h>
|
|
|
|
struct dma_coherent_mem {
|
|
void *virt_base;
|
|
u32 device_base;
|
|
int size;
|
|
int flags;
|
|
unsigned long *bitmap;
|
|
};
|
|
|
|
void *dma_alloc_coherent(struct device *dev, size_t size,
|
|
dma_addr_t *dma_handle, gfp_t gfp)
|
|
{
|
|
void *ret;
|
|
struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
|
|
int order = get_order(size);
|
|
/* ignore region specifiers */
|
|
gfp &= ~(__GFP_DMA | __GFP_HIGHMEM);
|
|
|
|
if (mem) {
|
|
int page = bitmap_find_free_region(mem->bitmap, mem->size,
|
|
order);
|
|
if (page >= 0) {
|
|
*dma_handle = mem->device_base + (page << PAGE_SHIFT);
|
|
ret = mem->virt_base + (page << PAGE_SHIFT);
|
|
memset(ret, 0, size);
|
|
return ret;
|
|
}
|
|
if (mem->flags & DMA_MEMORY_EXCLUSIVE)
|
|
return NULL;
|
|
}
|
|
|
|
if (dev == NULL || (dev->coherent_dma_mask < 0xffffffff))
|
|
gfp |= GFP_DMA;
|
|
|
|
ret = (void *)__get_free_pages(gfp, order);
|
|
|
|
if (ret != NULL) {
|
|
memset(ret, 0, size);
|
|
*dma_handle = virt_to_phys(ret);
|
|
}
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(dma_alloc_coherent);
|
|
|
|
void dma_free_coherent(struct device *dev, size_t size,
|
|
void *vaddr, dma_addr_t dma_handle)
|
|
{
|
|
struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
|
|
int order = get_order(size);
|
|
|
|
if (mem && vaddr >= mem->virt_base && vaddr < (mem->virt_base + (mem->size << PAGE_SHIFT))) {
|
|
int page = (vaddr - mem->virt_base) >> PAGE_SHIFT;
|
|
|
|
bitmap_release_region(mem->bitmap, page, order);
|
|
} else
|
|
free_pages((unsigned long)vaddr, order);
|
|
}
|
|
EXPORT_SYMBOL(dma_free_coherent);
|
|
|
|
int dma_declare_coherent_memory(struct device *dev, dma_addr_t bus_addr,
|
|
dma_addr_t device_addr, size_t size, int flags)
|
|
{
|
|
void __iomem *mem_base = NULL;
|
|
int pages = size >> PAGE_SHIFT;
|
|
int bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);
|
|
|
|
if ((flags & (DMA_MEMORY_MAP | DMA_MEMORY_IO)) == 0)
|
|
goto out;
|
|
if (!size)
|
|
goto out;
|
|
if (dev->dma_mem)
|
|
goto out;
|
|
|
|
/* FIXME: this routine just ignores DMA_MEMORY_INCLUDES_CHILDREN */
|
|
|
|
mem_base = ioremap(bus_addr, size);
|
|
if (!mem_base)
|
|
goto out;
|
|
|
|
dev->dma_mem = kzalloc(sizeof(struct dma_coherent_mem), GFP_KERNEL);
|
|
if (!dev->dma_mem)
|
|
goto out;
|
|
dev->dma_mem->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
|
|
if (!dev->dma_mem->bitmap)
|
|
goto free1_out;
|
|
|
|
dev->dma_mem->virt_base = mem_base;
|
|
dev->dma_mem->device_base = device_addr;
|
|
dev->dma_mem->size = pages;
|
|
dev->dma_mem->flags = flags;
|
|
|
|
if (flags & DMA_MEMORY_MAP)
|
|
return DMA_MEMORY_MAP;
|
|
|
|
return DMA_MEMORY_IO;
|
|
|
|
free1_out:
|
|
kfree(dev->dma_mem);
|
|
out:
|
|
if (mem_base)
|
|
iounmap(mem_base);
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(dma_declare_coherent_memory);
|
|
|
|
void dma_release_declared_memory(struct device *dev)
|
|
{
|
|
struct dma_coherent_mem *mem = dev->dma_mem;
|
|
|
|
if(!mem)
|
|
return;
|
|
dev->dma_mem = NULL;
|
|
iounmap(mem->virt_base);
|
|
kfree(mem->bitmap);
|
|
kfree(mem);
|
|
}
|
|
EXPORT_SYMBOL(dma_release_declared_memory);
|
|
|
|
void *dma_mark_declared_memory_occupied(struct device *dev,
|
|
dma_addr_t device_addr, size_t size)
|
|
{
|
|
struct dma_coherent_mem *mem = dev->dma_mem;
|
|
int pages = (size + (device_addr & ~PAGE_MASK) + PAGE_SIZE - 1) >> PAGE_SHIFT;
|
|
int pos, err;
|
|
|
|
if (!mem)
|
|
return ERR_PTR(-EINVAL);
|
|
|
|
pos = (device_addr - mem->device_base) >> PAGE_SHIFT;
|
|
err = bitmap_allocate_region(mem->bitmap, pos, get_order(pages));
|
|
if (err != 0)
|
|
return ERR_PTR(err);
|
|
return mem->virt_base + (pos << PAGE_SHIFT);
|
|
}
|
|
EXPORT_SYMBOL(dma_mark_declared_memory_occupied);
|