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linux-next/include/linux/dma-iommu.h
Krzysztof Kozlowski 00085f1efa dma-mapping: use unsigned long for dma_attrs
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>
2016-08-04 08:50:07 -04:00

86 lines
2.7 KiB
C

/*
* Copyright (C) 2014-2015 ARM Ltd.
*
* 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef __DMA_IOMMU_H
#define __DMA_IOMMU_H
#ifdef __KERNEL__
#include <asm/errno.h>
#ifdef CONFIG_IOMMU_DMA
#include <linux/iommu.h>
int iommu_dma_init(void);
/* Domain management interface for IOMMU drivers */
int iommu_get_dma_cookie(struct iommu_domain *domain);
void iommu_put_dma_cookie(struct iommu_domain *domain);
/* Setup call for arch DMA mapping code */
int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base, u64 size);
/* General helpers for DMA-API <-> IOMMU-API interaction */
int dma_direction_to_prot(enum dma_data_direction dir, bool coherent);
/*
* These implement the bulk of the relevant DMA mapping callbacks, but require
* the arch code to take care of attributes and cache maintenance
*/
struct page **iommu_dma_alloc(struct device *dev, size_t size, gfp_t gfp,
unsigned long attrs, int prot, dma_addr_t *handle,
void (*flush_page)(struct device *, const void *, phys_addr_t));
void iommu_dma_free(struct device *dev, struct page **pages, size_t size,
dma_addr_t *handle);
int iommu_dma_mmap(struct page **pages, size_t size, struct vm_area_struct *vma);
dma_addr_t iommu_dma_map_page(struct device *dev, struct page *page,
unsigned long offset, size_t size, int prot);
int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg,
int nents, int prot);
/*
* Arch code with no special attribute handling may use these
* directly as DMA mapping callbacks for simplicity
*/
void iommu_dma_unmap_page(struct device *dev, dma_addr_t handle, size_t size,
enum dma_data_direction dir, unsigned long attrs);
void iommu_dma_unmap_sg(struct device *dev, struct scatterlist *sg, int nents,
enum dma_data_direction dir, unsigned long attrs);
int iommu_dma_supported(struct device *dev, u64 mask);
int iommu_dma_mapping_error(struct device *dev, dma_addr_t dma_addr);
#else
struct iommu_domain;
static inline int iommu_dma_init(void)
{
return 0;
}
static inline int iommu_get_dma_cookie(struct iommu_domain *domain)
{
return -ENODEV;
}
static inline void iommu_put_dma_cookie(struct iommu_domain *domain)
{
}
#endif /* CONFIG_IOMMU_DMA */
#endif /* __KERNEL__ */
#endif /* __DMA_IOMMU_H */