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SubjectRe: [RFC PATCH 02/11] ppc: allow direct and iommu to coexist
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On Fri, 2010-10-08 at 10:33 -0700, Nishanth Aravamudan wrote:
> Replace the union with just the multiple fields, ifdef on CONFIG_PPC64.
>
> Future pseries boxes will allow a 64 bit dma mapping covering all
> memory, coexisting with a smaller iommu window in 32 bit pci space.
>
> The cell fixed mapping would also like both to coexist.
>
> Signed-off-by: Milton Miller <miltonm@bga.com>
> Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>
> ---
> I used the ifdef guard of CONFIG_PPC64 according to the current makefile
> for iommu.c. One set is burried in the middle of iommu.h.

I dislike the ifdef's ...

Also, why remove the union ? IE. Do we really them to co-exist for a
given device ? I'm doing something similar for another (not released
yet) processor where I'm flicking between direct and iommu at
set_dma_mask time, it's easy enough to change the union content.

Cheers,
Ben.

> ---
> arch/powerpc/include/asm/device.h | 14 ++++++--------
> arch/powerpc/include/asm/dma-mapping.h | 4 ++--
> arch/powerpc/include/asm/iommu.h | 6 ++++--
> 3 files changed, 12 insertions(+), 12 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/device.h b/arch/powerpc/include/asm/device.h
> index 16d25c0..ed883ea 100644
> --- a/arch/powerpc/include/asm/device.h
> +++ b/arch/powerpc/include/asm/device.h
> @@ -19,14 +19,12 @@ struct dev_archdata {
> /* DMA operations on that device */
> struct dma_map_ops *dma_ops;
>
> - /*
> - * When an iommu is in use, dma_data is used as a ptr to the base of the
> - * iommu_table. Otherwise, it is a simple numerical offset.
> - */
> - union {
> - dma_addr_t dma_offset;
> - void *iommu_table_base;
> - } dma_data;
> + /* dma_offset is used by swiotlb and direct dma ops, but no iommu */
> + dma_addr_t dma_offset;
> +
> +#ifdef CONFIG_PPC64
> + void *iommu_table_base;
> +#endif
>
> #ifdef CONFIG_SWIOTLB
> dma_addr_t max_direct_dma_addr;
> diff --git a/arch/powerpc/include/asm/dma-mapping.h b/arch/powerpc/include/asm/dma-mapping.h
> index 8c9c6ad..644103a 100644
> --- a/arch/powerpc/include/asm/dma-mapping.h
> +++ b/arch/powerpc/include/asm/dma-mapping.h
> @@ -100,7 +100,7 @@ static inline void set_dma_ops(struct device *dev, struct dma_map_ops *ops)
> static inline dma_addr_t get_dma_offset(struct device *dev)
> {
> if (dev)
> - return dev->archdata.dma_data.dma_offset;
> + return dev->archdata.dma_offset;
>
> return PCI_DRAM_OFFSET;
> }
> @@ -108,7 +108,7 @@ static inline dma_addr_t get_dma_offset(struct device *dev)
> static inline void set_dma_offset(struct device *dev, dma_addr_t off)
> {
> if (dev)
> - dev->archdata.dma_data.dma_offset = off;
> + dev->archdata.dma_offset = off;
> }
>
> /* this will be removed soon */
> diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/asm/iommu.h
> index edfc980..0f605a4 100644
> --- a/arch/powerpc/include/asm/iommu.h
> +++ b/arch/powerpc/include/asm/iommu.h
> @@ -70,15 +70,17 @@ struct iommu_table {
>
> struct scatterlist;
>
> +#ifdef CONFIG_PPC64
> static inline void set_iommu_table_base(struct device *dev, void *base)
> {
> - dev->archdata.dma_data.iommu_table_base = base;
> + dev->archdata.iommu_table_base = base;
> }
>
> static inline void *get_iommu_table_base(struct device *dev)
> {
> - return dev->archdata.dma_data.iommu_table_base;
> + return dev->archdata.iommu_table_base;
> }
> +#endif
>
> /* Frees table for an individual device node */
> extern void iommu_free_table(struct iommu_table *tbl, const char *node_name);




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