![Krzysztof Kozlowski](/assets/img/avatar_default.png)
The dma-mapping core and the implementations do not change the DMA attributes passed by pointer. Thus the pointer can point to const data. However the attributes do not have to be a bitfield. Instead unsigned long will do fine: 1. This is just simpler. Both in terms of reading the code and setting attributes. Instead of initializing local attributes on the stack and passing pointer to it to dma_set_attr(), just set the bits. 2. It brings safeness and checking for const correctness because the attributes are passed by value. Semantic patches for this change (at least most of them): virtual patch virtual context @r@ identifier f, attrs; @@ f(..., - struct dma_attrs *attrs + unsigned long attrs , ...) { ... } @@ identifier r.f; @@ f(..., - NULL + 0 ) and // Options: --all-includes virtual patch virtual context @r@ identifier f, attrs; type t; @@ t f(..., struct dma_attrs *attrs); @@ identifier r.f; @@ f(..., - NULL + 0 ) Link: http://lkml.kernel.org/r/1468399300-5399-2-git-send-email-k.kozlowski@samsung.com Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> Acked-by: Vineet Gupta <vgupta@synopsys.com> Acked-by: Robin Murphy <robin.murphy@arm.com> Acked-by: Hans-Christian Noren Egtvedt <egtvedt@samfundet.no> Acked-by: Mark Salter <msalter@redhat.com> [c6x] Acked-by: Jesper Nilsson <jesper.nilsson@axis.com> [cris] Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> [drm] Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com> Acked-by: Joerg Roedel <jroedel@suse.de> [iommu] Acked-by: Fabien Dessenne <fabien.dessenne@st.com> [bdisp] Reviewed-by: Marek Szyprowski <m.szyprowski@samsung.com> [vb2-core] Acked-by: David Vrabel <david.vrabel@citrix.com> [xen] Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> [xen swiotlb] Acked-by: Joerg Roedel <jroedel@suse.de> [iommu] Acked-by: Richard Kuo <rkuo@codeaurora.org> [hexagon] Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> [m68k] Acked-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> [s390] Acked-by: Bjorn Andersson <bjorn.andersson@linaro.org> Acked-by: Hans-Christian Noren Egtvedt <egtvedt@samfundet.no> [avr32] Acked-by: Vineet Gupta <vgupta@synopsys.com> [arc] Acked-by: Robin Murphy <robin.murphy@arm.com> [arm64 and dma-iommu] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
120 lines
3.5 KiB
C
120 lines
3.5 KiB
C
/*
|
|
* Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corporation
|
|
*
|
|
* Provide default implementations of the DMA mapping callbacks for
|
|
* busses using the iommu infrastructure
|
|
*/
|
|
|
|
#include <linux/export.h>
|
|
#include <asm/iommu.h>
|
|
|
|
/*
|
|
* Generic iommu implementation
|
|
*/
|
|
|
|
/* 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,
|
|
unsigned long attrs)
|
|
{
|
|
return iommu_alloc_coherent(dev, get_iommu_table_base(dev), size,
|
|
dma_handle, dev->coherent_dma_mask, flag,
|
|
dev_to_node(dev));
|
|
}
|
|
|
|
static void dma_iommu_free_coherent(struct device *dev, size_t size,
|
|
void *vaddr, dma_addr_t dma_handle,
|
|
unsigned long attrs)
|
|
{
|
|
iommu_free_coherent(get_iommu_table_base(dev), size, vaddr, dma_handle);
|
|
}
|
|
|
|
/* Creates TCEs for a user provided buffer. The user buffer must be
|
|
* contiguous real kernel storage (not vmalloc). The address passed here
|
|
* comprises a page address and offset into that page. The dma_addr_t
|
|
* returned will point to the same byte within the page as was passed in.
|
|
*/
|
|
static dma_addr_t dma_iommu_map_page(struct device *dev, struct page *page,
|
|
unsigned long offset, size_t size,
|
|
enum dma_data_direction direction,
|
|
unsigned long attrs)
|
|
{
|
|
return iommu_map_page(dev, get_iommu_table_base(dev), page, offset,
|
|
size, device_to_mask(dev), direction, attrs);
|
|
}
|
|
|
|
|
|
static void dma_iommu_unmap_page(struct device *dev, dma_addr_t dma_handle,
|
|
size_t size, enum dma_data_direction direction,
|
|
unsigned long attrs)
|
|
{
|
|
iommu_unmap_page(get_iommu_table_base(dev), dma_handle, size, direction,
|
|
attrs);
|
|
}
|
|
|
|
|
|
static int dma_iommu_map_sg(struct device *dev, struct scatterlist *sglist,
|
|
int nelems, enum dma_data_direction direction,
|
|
unsigned long attrs)
|
|
{
|
|
return ppc_iommu_map_sg(dev, get_iommu_table_base(dev), sglist, nelems,
|
|
device_to_mask(dev), direction, attrs);
|
|
}
|
|
|
|
static void dma_iommu_unmap_sg(struct device *dev, struct scatterlist *sglist,
|
|
int nelems, enum dma_data_direction direction,
|
|
unsigned long attrs)
|
|
{
|
|
ppc_iommu_unmap_sg(get_iommu_table_base(dev), sglist, nelems,
|
|
direction, attrs);
|
|
}
|
|
|
|
/* We support DMA to/from any memory page via the iommu */
|
|
int dma_iommu_dma_supported(struct device *dev, u64 mask)
|
|
{
|
|
struct iommu_table *tbl = get_iommu_table_base(dev);
|
|
|
|
if (!tbl) {
|
|
dev_info(dev, "Warning: IOMMU dma not supported: mask 0x%08llx"
|
|
", table unavailable\n", mask);
|
|
return 0;
|
|
}
|
|
|
|
if (tbl->it_offset > (mask >> tbl->it_page_shift)) {
|
|
dev_info(dev, "Warning: IOMMU offset too big for device mask\n");
|
|
dev_info(dev, "mask: 0x%08llx, table offset: 0x%08lx\n",
|
|
mask, tbl->it_offset << tbl->it_page_shift);
|
|
return 0;
|
|
} else
|
|
return 1;
|
|
}
|
|
|
|
static u64 dma_iommu_get_required_mask(struct device *dev)
|
|
{
|
|
struct iommu_table *tbl = get_iommu_table_base(dev);
|
|
u64 mask;
|
|
if (!tbl)
|
|
return 0;
|
|
|
|
mask = 1ULL < (fls_long(tbl->it_offset + tbl->it_size) - 1);
|
|
mask += mask - 1;
|
|
|
|
return mask;
|
|
}
|
|
|
|
struct dma_map_ops dma_iommu_ops = {
|
|
.alloc = dma_iommu_alloc_coherent,
|
|
.free = dma_iommu_free_coherent,
|
|
.mmap = dma_direct_mmap_coherent,
|
|
.map_sg = dma_iommu_map_sg,
|
|
.unmap_sg = dma_iommu_unmap_sg,
|
|
.dma_supported = dma_iommu_dma_supported,
|
|
.map_page = dma_iommu_map_page,
|
|
.unmap_page = dma_iommu_unmap_page,
|
|
.get_required_mask = dma_iommu_get_required_mask,
|
|
};
|
|
EXPORT_SYMBOL(dma_iommu_ops);
|