diff mbox

[v8,01/17] arm: make SWIOTLB available

Message ID 1381351710-1876-1-git-send-email-stefano.stabellini@eu.citrix.com (mailing list archive)
State New, archived
Headers show

Commit Message

Stefano Stabellini Oct. 9, 2013, 8:48 p.m. UTC 
IOMMU_HELPER is needed because SWIOTLB calls iommu_is_span_boundary,
provided by lib/iommu_helper.c.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
CC: will.deacon@arm.com
CC: linux@arm.linux.org.uk

Changes in v7:
- dma_mark_clean: empty implementation;
- in dma_capable use coherent_dma_mask if dma_mask hasn't been
  allocated.

Changes in v6:
- check for dev->dma_mask being NULL in dma_capable.

Changes in v5:
- implement dma_mark_clean using dmac_flush_range.

Changes in v3:
- dma_capable: do not treat dma_mask as a limit;
- remove SWIOTLB dependency on NEED_SG_DMA_LENGTH.
---
 arch/arm/Kconfig                   |    6 +++++
 arch/arm/include/asm/dma-mapping.h |   37 ++++++++++++++++++++++++++++++++++++
 2 files changed, 43 insertions(+), 0 deletions(-)

Comments

Will Deacon Oct. 10, 2013, 9:43 a.m. UTC | #1 
On Wed, Oct 09, 2013 at 09:48:14PM +0100, Stefano Stabellini wrote:
> IOMMU_HELPER is needed because SWIOTLB calls iommu_is_span_boundary,
> provided by lib/iommu_helper.c.
> 
> Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> CC: will.deacon@arm.com
> CC: linux@arm.linux.org.uk

[...]

> diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h
> index 5b579b9..9aa5384 100644
> --- a/arch/arm/include/asm/dma-mapping.h
> +++ b/arch/arm/include/asm/dma-mapping.h
> @@ -10,6 +10,7 @@
>  
>  #include <asm-generic/dma-coherent.h>
>  #include <asm/memory.h>
> +#include <asm/cacheflush.h>
>  
>  #define DMA_ERROR_CODE	(~0)
>  extern struct dma_map_ops arm_dma_ops;
> @@ -86,6 +87,42 @@ static inline dma_addr_t virt_to_dma(struct device *dev, void *addr)
>  }
>  #endif
>  
> +static inline dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
> +{
> +	unsigned int offset = paddr & ~PAGE_MASK;
> +	return pfn_to_dma(dev, paddr >> PAGE_SHIFT) + offset;

__phys_to_pfn instead of the explicit shift?

> +}
> +
> +static inline phys_addr_t dma_to_phys(struct device *dev, dma_addr_t dev_addr)
> +{
> +	unsigned int offset = dev_addr & ~PAGE_MASK;
> +	return (dma_to_pfn(dev, dev_addr) << PAGE_SHIFT) + offset;i

then __pfn_to_phys here.

> +}
> +
> +static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size)
> +{
> +	u64 limit, mask;
> +	
> +	if (dev->dma_mask)
> +		mask = *dev->dma_mask;
> +	else 
> +		mask = dev->coherent_dma_mask;
> +
> +	if (mask == 0)
> +		return 0;
> +
> +	limit = (mask + 1) & ~mask;

This looks like homebrew alignment to me. Can you use __ALIGN_KERNEL_MASK or
one of thoese guys from kernel.h?

Will
Stefano Stabellini Oct. 15, 2013, 3:45 p.m. UTC | #2 
On Thu, 10 Oct 2013, Will Deacon wrote:
> On Wed, Oct 09, 2013 at 09:48:14PM +0100, Stefano Stabellini wrote:
> > IOMMU_HELPER is needed because SWIOTLB calls iommu_is_span_boundary,
> > provided by lib/iommu_helper.c.
> > 
> > Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> > Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> > CC: will.deacon@arm.com
> > CC: linux@arm.linux.org.uk
> 
> [...]
> 
> > diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h
> > index 5b579b9..9aa5384 100644
> > --- a/arch/arm/include/asm/dma-mapping.h
> > +++ b/arch/arm/include/asm/dma-mapping.h
> > @@ -10,6 +10,7 @@
> >  
> >  #include <asm-generic/dma-coherent.h>
> >  #include <asm/memory.h>
> > +#include <asm/cacheflush.h>
> >  
> >  #define DMA_ERROR_CODE	(~0)
> >  extern struct dma_map_ops arm_dma_ops;
> > @@ -86,6 +87,42 @@ static inline dma_addr_t virt_to_dma(struct device *dev, void *addr)
> >  }
> >  #endif
> >  
> > +static inline dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
> > +{
> > +	unsigned int offset = paddr & ~PAGE_MASK;
> > +	return pfn_to_dma(dev, paddr >> PAGE_SHIFT) + offset;
> 
> __phys_to_pfn instead of the explicit shift?
> 
> > +}
> > +
> > +static inline phys_addr_t dma_to_phys(struct device *dev, dma_addr_t dev_addr)
> > +{
> > +	unsigned int offset = dev_addr & ~PAGE_MASK;
> > +	return (dma_to_pfn(dev, dev_addr) << PAGE_SHIFT) + offset;i
> 
> then __pfn_to_phys here.

good point

> > +}
> > +
> > +static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size)
> > +{
> > +	u64 limit, mask;
> > +	
> > +	if (dev->dma_mask)
> > +		mask = *dev->dma_mask;
> > +	else 
> > +		mask = dev->coherent_dma_mask;
> > +
> > +	if (mask == 0)
> > +		return 0;
> > +
> > +	limit = (mask + 1) & ~mask;
> 
> This looks like homebrew alignment to me. Can you use __ALIGN_KERNEL_MASK or
> one of thoese guys from kernel.h?

It was suggested by Russell here:

http://marc.info/?l=linux-arm-kernel&m=137535542901235&w=2

I don't think that __ALIGN_KERNEL_MASK would be useful in this case.
I could add a comment to explain the purpose of the check though.
diff mbox

Patch

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index ba412e0..c0bfb33 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1832,6 +1832,12 @@  config CC_STACKPROTECTOR
 	  neutralized via a kernel panic.
 	  This feature requires gcc version 4.2 or above.
 
+config SWIOTLB
+	def_bool y
+
+config IOMMU_HELPER
+	def_bool SWIOTLB
+
 config XEN_DOM0
 	def_bool y
 	depends on XEN
diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h
index 5b579b9..9aa5384 100644
--- a/arch/arm/include/asm/dma-mapping.h
+++ b/arch/arm/include/asm/dma-mapping.h
@@ -10,6 +10,7 @@ 
 
 #include <asm-generic/dma-coherent.h>
 #include <asm/memory.h>
+#include <asm/cacheflush.h>
 
 #define DMA_ERROR_CODE	(~0)
 extern struct dma_map_ops arm_dma_ops;
@@ -86,6 +87,42 @@  static inline dma_addr_t virt_to_dma(struct device *dev, void *addr)
 }
 #endif
 
+static inline dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
+{
+	unsigned int offset = paddr & ~PAGE_MASK;
+	return pfn_to_dma(dev, paddr >> PAGE_SHIFT) + offset;
+}
+
+static inline phys_addr_t dma_to_phys(struct device *dev, dma_addr_t dev_addr)
+{
+	unsigned int offset = dev_addr & ~PAGE_MASK;
+	return (dma_to_pfn(dev, dev_addr) << PAGE_SHIFT) + offset;
+}
+
+static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size)
+{
+	u64 limit, mask;
+	
+	if (dev->dma_mask)
+		mask = *dev->dma_mask;
+	else 
+		mask = dev->coherent_dma_mask;
+
+	if (mask == 0)
+		return 0;
+
+	limit = (mask + 1) & ~mask;
+	if (limit && size > limit)
+		return 0;
+
+	if ((addr | (addr + size - 1)) & ~mask)
+		return 0;
+
+	return 1;
+}
+
+static inline void dma_mark_clean(void *addr, size_t size) { }
+
 /*
  * DMA errors are defined by all-bits-set in the DMA address.
  */