| Message ID | 1409327670-3495-3-git-send-email-will.deacon@arm.com |
|---|---|
| State | New |
| Headers | show |
On Friday 29 August 2014 16:54:25 Will Deacon wrote: > set_arch_dma_coherent_ops is called from of_dma_configure in order to > swizzle the architectural dma-mapping functions over to a cache-coherent > implementation. This is currently implemented only for ARM. > > In anticipation of re-using this mechanism for IOMMU-backed dma-mapping > ops too, this patch replaces the function with a broader > arch_setup_dma_ops callback which is also responsible for setting the > DMA mask and offset as well as selecting the correct mapping functions. > > A further advantage of this split is that it nicely isolates the > of-specific code from the dma-mapping code, allowing potential reuse by > other buses (e.g. PCI) in the future. > > Signed-off-by: Will Deacon <will.deacon@arm.com> Looks good, just one tiny comment > --- > arch/arm/include/asm/dma-mapping.h | 20 ++++++++++++++---- > drivers/of/platform.c | 42 ++++++++++---------------------------- > include/linux/dma-mapping.h | 8 +++----- > 3 files changed, 30 insertions(+), 40 deletions(-) > > diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h > index c45b61a4b4a5..936125ef3f3f 100644 > --- a/arch/arm/include/asm/dma-mapping.h > +++ b/arch/arm/include/asm/dma-mapping.h > @@ -121,12 +121,24 @@ static inline unsigned long dma_max_pfn(struct device *dev) > } > #define dma_max_pfn(dev) dma_max_pfn(dev) > > -static inline int set_arch_dma_coherent_ops(struct device *dev) > +static inline void arch_setup_dma_ops(struct device *dev, u64 mask, > + unsigned long offset, bool coherent) > { > - set_dma_ops(dev, &arm_coherent_dma_ops); > - return 0; > + dev->coherent_dma_mask = mask; > + > + /* > + * Set dma_mask to coherent_dma_mask by default if the architecture > + * code has not set it. > + */ > + if (!dev->dma_mask) > + dev->dma_mask = &dev->coherent_dma_mask; > + We are in architecture specific code here, and we know that this architecture has not set up the dev->dma_mask pointer, so we can remove the 'if (!dev->dma_mask)' Arnd
On Mon, Sep 01, 2014 at 03:27:30PM +0100, Arnd Bergmann wrote: > On Friday 29 August 2014 16:54:25 Will Deacon wrote: > > set_arch_dma_coherent_ops is called from of_dma_configure in order to > > swizzle the architectural dma-mapping functions over to a cache-coherent > > implementation. This is currently implemented only for ARM. > > > > In anticipation of re-using this mechanism for IOMMU-backed dma-mapping > > ops too, this patch replaces the function with a broader > > arch_setup_dma_ops callback which is also responsible for setting the > > DMA mask and offset as well as selecting the correct mapping functions. > > > > A further advantage of this split is that it nicely isolates the > > of-specific code from the dma-mapping code, allowing potential reuse by > > other buses (e.g. PCI) in the future. > > > > Signed-off-by: Will Deacon <will.deacon@arm.com> > > Looks good, just one tiny comment > > > --- > > arch/arm/include/asm/dma-mapping.h | 20 ++++++++++++++---- > > drivers/of/platform.c | 42 ++++++++++---------------------------- > > include/linux/dma-mapping.h | 8 +++----- > > 3 files changed, 30 insertions(+), 40 deletions(-) > > > > diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h > > index c45b61a4b4a5..936125ef3f3f 100644 > > --- a/arch/arm/include/asm/dma-mapping.h > > +++ b/arch/arm/include/asm/dma-mapping.h > > @@ -121,12 +121,24 @@ static inline unsigned long dma_max_pfn(struct device *dev) > > } > > #define dma_max_pfn(dev) dma_max_pfn(dev) > > > > -static inline int set_arch_dma_coherent_ops(struct device *dev) > > +static inline void arch_setup_dma_ops(struct device *dev, u64 mask, > > + unsigned long offset, bool coherent) > > { > > - set_dma_ops(dev, &arm_coherent_dma_ops); > > - return 0; > > + dev->coherent_dma_mask = mask; > > + > > + /* > > + * Set dma_mask to coherent_dma_mask by default if the architecture > > + * code has not set it. > > + */ > > + if (!dev->dma_mask) > > + dev->dma_mask = &dev->coherent_dma_mask; > > + > > We are in architecture specific code here, and we know that this > architecture has not set up the dev->dma_mask pointer, so we can > remove the 'if (!dev->dma_mask)' Good point; I'll fix it. Thanks, Will
diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h index c45b61a4b4a5..936125ef3f3f 100644 --- a/arch/arm/include/asm/dma-mapping.h +++ b/arch/arm/include/asm/dma-mapping.h @@ -121,12 +121,24 @@ static inline unsigned long dma_max_pfn(struct device *dev) } #define dma_max_pfn(dev) dma_max_pfn(dev) -static inline int set_arch_dma_coherent_ops(struct device *dev) +static inline void arch_setup_dma_ops(struct device *dev, u64 mask, + unsigned long offset, bool coherent) { - set_dma_ops(dev, &arm_coherent_dma_ops); - return 0; + dev->coherent_dma_mask = mask; + + /* + * Set dma_mask to coherent_dma_mask by default if the architecture + * code has not set it. + */ + if (!dev->dma_mask) + dev->dma_mask = &dev->coherent_dma_mask; + + dev->dma_pfn_offset = offset; + + if (coherent) + set_dma_ops(dev, &arm_coherent_dma_ops); } -#define set_arch_dma_coherent_ops(dev) set_arch_dma_coherent_ops(dev) +#define arch_setup_dma_ops arch_setup_dma_ops static inline dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr) { diff --git a/drivers/of/platform.c b/drivers/of/platform.c index 0197725e033a..484c558c63a6 100644 --- a/drivers/of/platform.c +++ b/drivers/of/platform.c @@ -164,43 +164,23 @@ static void of_dma_configure(struct platform_device *pdev) { u64 dma_addr, paddr, size; int ret; + bool coherent; + unsigned long offset; struct device *dev = &pdev->dev; - /* - * Set default dma-mask to 32 bit. Drivers are expected to setup - * the correct supported dma_mask. - */ - dev->coherent_dma_mask = DMA_BIT_MASK(32); - - /* - * Set it to coherent_dma_mask by default if the architecture - * code has not set it. - */ - if (!dev->dma_mask) - dev->dma_mask = &dev->coherent_dma_mask; + ret = of_dma_get_range(dev->of_node, &dma_addr, &paddr, &size); + offset = ret < 0 ? 0 : PFN_DOWN(paddr - dma_addr); + dev_dbg(dev, "dma_pfn_offset(%#08lx)\n", dev->dma_pfn_offset); - /* - * if dma-coherent property exist, call arch hook to setup - * dma coherent operations. - */ - if (of_dma_is_coherent(dev->of_node)) { - set_arch_dma_coherent_ops(dev); - dev_dbg(dev, "device is dma coherent\n"); - } + coherent = of_dma_is_coherent(dev->of_node); + dev_dbg(dev, "device is%sdma coherent\n", + coherent ? " " : " not "); /* - * if dma-ranges property doesn't exist - just return else - * setup the dma offset + * Set default dma-mask to 32 bit. Drivers are expected to setup + * the correct supported dma_mask. */ - ret = of_dma_get_range(dev->of_node, &dma_addr, &paddr, &size); - if (ret < 0) { - dev_dbg(dev, "no dma range information to setup\n"); - return; - } - - /* DMA ranges found. Calculate and set dma_pfn_offset */ - dev->dma_pfn_offset = PFN_DOWN(paddr - dma_addr); - dev_dbg(dev, "dma_pfn_offset(%#08lx)\n", dev->dma_pfn_offset); + arch_setup_dma_ops(dev, DMA_BIT_MASK(32), offset, coherent); } /** diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h index 931b70986272..0f7f7b68b0db 100644 --- a/include/linux/dma-mapping.h +++ b/include/linux/dma-mapping.h @@ -129,11 +129,9 @@ static inline int dma_coerce_mask_and_coherent(struct device *dev, u64 mask) extern u64 dma_get_required_mask(struct device *dev); -#ifndef set_arch_dma_coherent_ops -static inline int set_arch_dma_coherent_ops(struct device *dev) -{ - return 0; -} +#ifndef arch_setup_dma_ops +static inline void arch_setup_dma_ops(struct device *dev, u64 mask, + unsigned long offset, bool coherent) { } #endif static inline unsigned int dma_get_max_seg_size(struct device *dev)
set_arch_dma_coherent_ops is called from of_dma_configure in order to swizzle the architectural dma-mapping functions over to a cache-coherent implementation. This is currently implemented only for ARM. In anticipation of re-using this mechanism for IOMMU-backed dma-mapping ops too, this patch replaces the function with a broader arch_setup_dma_ops callback which is also responsible for setting the DMA mask and offset as well as selecting the correct mapping functions. A further advantage of this split is that it nicely isolates the of-specific code from the dma-mapping code, allowing potential reuse by other buses (e.g. PCI) in the future. Signed-off-by: Will Deacon <will.deacon@arm.com> --- arch/arm/include/asm/dma-mapping.h | 20 ++++++++++++++---- drivers/of/platform.c | 42 ++++++++++---------------------------- include/linux/dma-mapping.h | 8 +++----- 3 files changed, 30 insertions(+), 40 deletions(-)