/*
* Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corporation
*
* Provide default implementations of the DMA mapping callbacks for
* directly mapped busses and busses using the iommu infrastructure
*/
#include <linux/device.h>
#include <linux/dma-mapping.h>
#include <asm/bug.h>
#include <asm/iommu.h>
#include <asm/abs_addr.h>
/*
* Generic iommu implementation
*/
static inline unsigned long device_to_mask(struct device *dev)
{
if (dev->dma_mask && *dev->dma_mask)
return *dev->dma_mask;
/* Assume devices without mask can take 32 bit addresses */
return 0xfffffffful;
}
/* Allocates a contiguous real buffer and creates mappings over it.
* Returns the virtual address of the buffer and sets dma_handle
* to the dma address (mapping) of the first page.
*/
static void *dma_iommu_alloc_coherent(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t flag)
{
return iommu_alloc_coherent(dev->archdata.dma_data, size, dma_handle,
device_to_mask(dev), flag,
dev->archdata.numa_node);
}
static void dma_iommu_free_coherent(struct device *dev, size_t size,
void *vaddr, dma_addr_t dma_handle)
{
iommu_free_coherent(dev->archdata.dma_data, size, vaddr, dma_handle);
}
/* Creates TCEs for a user provided buffer. The user buffer must be
* contiguous real kernel storage (not vmalloc). The address of the buffer
* passed here is the kernel (virtual) address of the buffer. The buffer
* need not be page aligned, the dma_addr_t returned will point to the same
* byte within the page as vaddr.
*/
static dma_addr_t dma_iommu_map_single(struct device *dev, void *vaddr,
size_t size,
enum dma_data_direction direction)
{
return iommu_map_single(dev->archdata.dma_data, vaddr, size,
device_to_mask(dev), direction);
}
static void dma_iommu_unmap_single(struct device *dev, dma_addr_t dma_handle,
size_t size,
enum dma_data_direction direction)
{
iommu_unmap_single(dev->archdata.dma_data, dma_handle, size, direction);
}
static int dma_iommu_map_sg(struct device *dev, struct scatterlist *sglist,
int nelems, enum dma_data_direction direction)
{
return iommu_map_sg(dev->archdata.dma_data, sglist, nelems,
device_to_mask(dev), direction);
}
static void dma_iommu_unmap_sg(struct device *dev, struct scatterlist *sglist,
int nelems, enum dma_data_direction direction)
{
iommu_unmap_sg(dev->archdata.dma_data, sglist, nelems, direction);
}
/* We support DMA to/from any memory page via the iommu */
static int dma_iommu_dma_supported(struct device *dev, u64 mask)
{
struct iommu_table *tbl = dev->archdata.dma_data;
if (!tbl || tbl->it_offset > mask) {
printk(KERN_INFO
"Warning: IOMMU offset too big for device mask\n");
if (tbl)
printk(KERN_INFO
"mask: 0x%08lx, table offset: 0x%08lx\n",
mask, tbl->it_offset);
else
printk(KERN_INFO "mask: 0x%08lx, table unavailable\n",
mask);
return 0;
} else
return 1;
}
struct dma_mapping_ops dma_iommu_ops = {
.alloc_coherent = dma_iommu_alloc_coherent,
.free_coherent = dma_iommu_free_coherent,
.map_single = dma_iommu_map_single,
.unmap_single = dma_iommu_unmap_single,
.map_sg = dma_iommu_map_sg,
.unmap_sg = dma_iommu_unmap_sg,
.dma_supported = dma_iommu_dma_supported,
};
EXPORT_SYMBOL(dma_iommu_ops);
/*
* Generic direct DMA implementation
*
* This implementation supports a global offset that can be applied if
* the address at which memory is visible to devices is not 0.
*/
unsigned long dma_direct_offset;
static void *dma_direct_alloc_coherent(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t flag)
{
struct page *page;
void *ret;
int node = dev->archdata.numa_node;
/* TODO: Maybe use the numa node here too ? */
page = alloc_pages_node(node, flag, get_order(size));
if (page == NULL)
return NULL;
ret = page_address(page);
memset(ret, 0, size);
*dma_handle = virt_to_abs(ret) | dma_direct_offset;
return ret;
}
static void dma_direct_free_coherent(struct device *dev, size_t size,
void *vaddr, dma_addr_t dma_handle)
{
free_pages((unsigned long)vaddr, get_order(size));
}
static dma_addr_t dma_direct_map_single(struct device *dev, void *ptr,
size_t size,
enum dma_data_direction direction)
{
return virt_to_abs(ptr) | dma_direct_offset;
}
static void dma_direct_unmap_single(struct device *dev, dma_addr_t dma_addr,
size_t size,
enum dma_data_direction direction)
{
}
static int dma_direct_map_sg(struct device *dev, struct scatterlist *sg,
int nents, enum dma_data_direction direction)
{
int i;
for (i = 0; i < nents; i++, sg++) {
sg->dma_address = (page_to_phys(sg->page) + sg->offset) |
dma_direct_offset;
sg->dma_length = sg->length;
}
return nents;
}
static void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sg,
int nents, enum dma_data_direction direction)
{
}
static int dma_direct_dma_supported(struct device *dev, u64 mask)
{
/* Could be improved to check for memory though it better be
* done via some global so platforms can set the limit in case
* they have limited DMA windows
*/
return mask >= DMA_32BIT_MASK;
}
struct dma_mapping_ops dma_direct_ops = {
.alloc_coherent = dma_direct_alloc_coherent,
.free_coherent = dma_direct_free_coherent,
.map_single = dma_direct_map_single,
.unmap_single = dma_direct_unmap_single,
.map_sg = dma_direct_map_sg,
.unmap_sg = dma_direct_unmap_sg,
.dma_supported = dma_direct_dma_supported,
};
EXPORT_SYMBOL(dma_direct_ops);
