2014-01-13 13:53:15

by Thierry Reding

Subject: [RFC] dma-mapping: Provide write-combine allocations

Provide an implementation for dma_{alloc,free}_writecombine() when the
architecture supports DMA attributes.

Signed-off-by: Thierry Reding <[email protected]>
---
arch/arm/include/asm/dma-mapping.h | 16 ----------------
include/linux/dma-mapping.h | 16 ++++++++++++++++
2 files changed, 16 insertions(+), 16 deletions(-)

diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h
index e701a4d9aa59..96b7634a7edc 100644
--- a/arch/arm/include/asm/dma-mapping.h
+++ b/arch/arm/include/asm/dma-mapping.h
@@ -242,22 +242,6 @@ 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/linux/dma-mapping.h b/include/linux/dma-mapping.h
index fd4aee29ad10..8475e02b4bd1 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -249,6 +249,22 @@ 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);
+}
#endif /* CONFIG_HAVE_DMA_ATTRS */

#ifdef CONFIG_NEED_DMA_MAP_STATE
--
1.8.4.2

2014-01-14 09:15:27

by Marek Szyprowski

Subject: Re: [RFC] dma-mapping: Provide write-combine allocations

Hello,

On 2014-01-13 14:53, Thierry Reding wrote:
> Provide an implementation for dma_{alloc,free}_writecombine() when the
> architecture supports DMA attributes.
>
> Signed-off-by: Thierry Reding <[email protected]>
> ---
> arch/arm/include/asm/dma-mapping.h | 16 ----------------
> include/linux/dma-mapping.h | 16 ++++++++++++++++
> 2 files changed, 16 insertions(+), 16 deletions(-)
>
> diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h
> index e701a4d9aa59..96b7634a7edc 100644
> --- a/arch/arm/include/asm/dma-mapping.h
> +++ b/arch/arm/include/asm/dma-mapping.h
> @@ -242,22 +242,6 @@ 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/linux/dma-mapping.h b/include/linux/dma-mapping.h
> index fd4aee29ad10..8475e02b4bd1 100644
> --- a/include/linux/dma-mapping.h
> +++ b/include/linux/dma-mapping.h
> @@ -249,6 +249,22 @@ 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);
> +}
> #endif /* CONFIG_HAVE_DMA_ATTRS */
>
> #ifdef CONFIG_NEED_DMA_MAP_STATE

I would also add dma_mmap_writecombine() to the above functions.

Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland