Re: [PATCH v2] dma-mapping: Provide write-combine allocations

Russell King - ARM Linux
2014-08-01T15:19:36Z

On Fri, Aug 01, 2014 at 02:40:59PM +0200, Thierry Reding wrote:
> On Fri, Jun 27, 2014 at 11:56:58AM +0200, Thierry Reding wrote:
> > From: Thierry Reding <treding@nvidia.com>
> >
> > Provide an implementation for dma_{alloc,free,mmap}_writecombine() when
> > the architecture supports DMA attributes.
> >
> > Signed-off-by: Thierry Reding <treding@nvidia.com>
> > ---
> > Changes in v2:
> > - Add a generic dma_mmap_writecombine() function
> >
> > arch/arm/include/asm/dma-mapping.h | 16 ----------------
> > include/asm-generic/dma-mapping-common.h | 8 --------
> > include/linux/dma-mapping.h | 26 ++++++++++++++++++++++++++
> > 3 files changed, 26 insertions(+), 24 deletions(-)
>
> Ping?

I have no problem with this, but I don't think I can say yes to it; that
depends whether other people are happy for this to live in
include/linux/dma-mapping.h.

I guess consent for this change can only come by no one objecting to it
after several postings.

> > diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h
> > index c45b61a4b4a5..85738b200023 100644
> > --- a/arch/arm/include/asm/dma-mapping.h
> > +++ b/arch/arm/include/asm/dma-mapping.h
> > @@ -265,22 +265,6 @@ extern int arm_dma_mmap(struct device *dev, struct vm_area_struct *vma,
> > void *cpu_addr, dma_addr_t dma_addr, size_t size,
> > struct dma_attrs *attrs);
> >
> > -static inline void *dma_alloc_writecombine(struct device *dev, size_t size,
> > - dma_addr_t *dma_handle, gfp_t flag)
> > -{
> > - DEFINE_DMA_ATTRS(attrs);
> > - dma_set_attr(DMA_ATTR_WRITE_COMBINE, &attrs);
> > - return dma_alloc_attrs(dev, size, dma_handle, flag, &attrs);
> > -}
> > -
> > -static inline void dma_free_writecombine(struct device *dev, size_t size,
> > - void *cpu_addr, dma_addr_t dma_handle)
> > -{
> > - DEFINE_DMA_ATTRS(attrs);
> > - dma_set_attr(DMA_ATTR_WRITE_COMBINE, &attrs);
> > - return dma_free_attrs(dev, size, cpu_addr, dma_handle, &attrs);
> > -}
> > -
> > /*
> > * This can be called during early boot to increase the size of the atomic
> > * coherent DMA pool above the default value of 256KiB. It must be called
> > diff --git a/include/asm-generic/dma-mapping-common.h b/include/asm-generic/dma-mapping-common.h
> > index de8bf89940f8..d137431bf26f 100644
> > --- a/include/asm-generic/dma-mapping-common.h
> > +++ b/include/asm-generic/dma-mapping-common.h
> > @@ -205,14 +205,6 @@ dma_mmap_attrs(struct device *dev, struct vm_area_struct *vma, void *cpu_addr,
> >
> > #define dma_mmap_coherent(d, v, c, h, s) dma_mmap_attrs(d, v, c, h, s, NULL)
> >
> > -static inline int dma_mmap_writecombine(struct device *dev, struct vm_area_struct *vma,
> > - void *cpu_addr, dma_addr_t dma_addr, size_t size)
> > -{
> > - DEFINE_DMA_ATTRS(attrs);
> > - dma_set_attr(DMA_ATTR_WRITE_COMBINE, &attrs);
> > - return dma_mmap_attrs(dev, vma, cpu_addr, dma_addr, size, &attrs);
> > -}
> > -
> > int
> > dma_common_get_sgtable(struct device *dev, struct sg_table *sgt,
> > void *cpu_addr, dma_addr_t dma_addr, size_t size);
> > diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
> > index 931b70986272..d5d388160f42 100644
> > --- a/include/linux/dma-mapping.h
> > +++ b/include/linux/dma-mapping.h
> > @@ -263,6 +263,32 @@ struct dma_attrs;
> > #define dma_unmap_sg_attrs(dev, sgl, nents, dir, attrs) \
> > dma_unmap_sg(dev, sgl, nents, dir)
> >
> > +#else
> > +static inline void *dma_alloc_writecombine(struct device *dev, size_t size,
> > + dma_addr_t *dma_addr, gfp_t gfp)
> > +{
> > + DEFINE_DMA_ATTRS(attrs);
> > + dma_set_attr(DMA_ATTR_WRITE_COMBINE, &attrs);
> > + return dma_alloc_attrs(dev, size, dma_addr, gfp, &attrs);
> > +}
> > +
> > +static inline void dma_free_writecombine(struct device *dev, size_t size,
> > + void *cpu_addr, dma_addr_t dma_addr)
> > +{
> > + DEFINE_DMA_ATTRS(attrs);
> > + dma_set_attr(DMA_ATTR_WRITE_COMBINE, &attrs);
> > + return dma_free_attrs(dev, size, cpu_addr, dma_addr, &attrs);
> > +}
> > +
> > +static inline int dma_mmap_writecombine(struct device *dev,
> > + struct vm_area_struct *vma,
> > + void *cpu_addr, dma_addr_t dma_addr,
> > + size_t size)
> > +{
> > + DEFINE_DMA_ATTRS(attrs);
> > + dma_set_attr(DMA_ATTR_WRITE_COMBINE, &attrs);
> > + return dma_mmap_attrs(dev, vma, cpu_addr, dma_addr, size, &attrs);
> > +}
> > #endif /* CONFIG_HAVE_DMA_ATTRS */
> >
> > #ifdef CONFIG_NEED_DMA_MAP_STATE
> > --
> > 2.0.0
> >

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