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SubjectRe: [PATCH 02/11] x86: introduce arch-specific dma-mapping interface
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On Mon, 1 Jun 2009 16:32:54 +0100
Ian Campbell <ian.campbell@citrix.com> wrote:

> dma_map_range is intended to replace usage of both
> swiotlb_arch_range_needs_mapping and
> swiotlb_arch_address_needs_mapping as __weak functions as well as
> replacing is_buffer_dma_capable.
>
> phys_to_dma and dma_to_phys are intended to replace
> swiotlb_phys_to_bus and swiotlb_bus_to_phys. I choose to use dma
> rather than bus since a) it matches the parameters and b) avoids
> confusion on x86 with the existing (but deprecated) virt_to_bus
> function which relates to ISA device DMA.
>
> Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
> Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
> Cc: Jeremy Fitzhardinge <jeremy@goop.org>
> Cc: Olaf Kirch <okir@suse.de>
> Cc: Greg KH <gregkh@suse.de>
> Cc: x86@kernel.org
> ---
> arch/x86/include/asm/dma-mapping.h | 7 +++++++
> arch/x86/kernel/pci-dma.c | 26 ++++++++++++++++++++++++++
> 2 files changed, 33 insertions(+), 0 deletions(-)
>
> diff --git a/arch/x86/include/asm/dma-mapping.h b/arch/x86/include/asm/dma-mapping.h
> index 916cbb6..be8cb22 100644
> --- a/arch/x86/include/asm/dma-mapping.h
> +++ b/arch/x86/include/asm/dma-mapping.h
> @@ -47,6 +47,9 @@ static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
> #define dma_free_noncoherent(d, s, v, h) dma_free_coherent(d, s, v, h)
> #define dma_is_consistent(d, h) (1)
>
> +extern dma_addr_t phys_to_dma(struct device *hwdev, phys_addr_t paddr);
> +extern phys_addr_t dma_to_phys(struct device *hwdev, dma_addr_t daddr);
> +
> extern int dma_supported(struct device *hwdev, u64 mask);
> extern int dma_set_mask(struct device *dev, u64 mask);
>
> @@ -309,4 +312,8 @@ static inline void dma_free_coherent(struct device *dev, size_t size,
> ops->free_coherent(dev, size, vaddr, bus);
> }
>
> +extern bool dma_map_range(struct device *dev, u64 mask,
> + phys_addr_t addr, size_t size,
> + dma_addr_t *dma_addr_p);
> +
> #endif
> diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
> index 745579b..f4c1b03 100644
> --- a/arch/x86/kernel/pci-dma.c
> +++ b/arch/x86/kernel/pci-dma.c
> @@ -59,6 +59,32 @@ int dma_set_mask(struct device *dev, u64 mask)
> }
> EXPORT_SYMBOL(dma_set_mask);
>
> +dma_addr_t phys_to_dma(struct device *hwdev, phys_addr_t paddr)
> +{
> + return paddr;
> +}
> +EXPORT_SYMBOL_GPL(phys_to_dma);
> +
> +phys_addr_t dma_to_phys(struct device *hwdev, dma_addr_t daddr)
> +{
> + return daddr;
> +}
> +EXPORT_SYMBOL_GPL(dma_to_phys);
> +
> +bool dma_map_range(struct device *dev, u64 mask,
> + phys_addr_t addr, size_t size,
> + dma_addr_t *dma_addr_p)
> +{
> + dma_addr_t dma_addr = phys_to_dma(dev, addr);
> +
> + if (dma_addr + size > mask)
> + return false;
> +
> + *dma_addr_p = dma_addr;
> + return true;
> +}
> +EXPORT_SYMBOL_GPL(dma_map_range);
> +

Why can't the above functions live in arch/include/asm/dma-mapping.h,
where they should live?


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