On Fri, Feb 06, 2015 at 02:55:14PM +0000, Robin Murphy wrote:
> Taking some inspiration from the arch/arm code, implement the
> arch-specific side of the DMA mapping ops using the new IOMMU-DMA layer.
Is anybody looking at porting arch/arm/ over to this?
> Signed-off-by: Robin Murphy <robin.mur...@arm.com>
> ---
> arch/arm64/include/asm/device.h | 3 +
> arch/arm64/include/asm/dma-mapping.h | 17 ++
> arch/arm64/mm/dma-mapping.c | 320
> +++++++++++++++++++++++++++++++++++
> 3 files changed, 340 insertions(+)
>
> diff --git a/arch/arm64/include/asm/device.h b/arch/arm64/include/asm/device.h
> index 243ef25..510cee1 100644
> --- a/arch/arm64/include/asm/device.h
> +++ b/arch/arm64/include/asm/device.h
> @@ -20,6 +20,9 @@ struct dev_archdata {
> struct dma_map_ops *dma_ops;
> #ifdef CONFIG_IOMMU_API
> void *iommu; /* private IOMMU data */
> +#ifdef CONFIG_IOMMU_DMA
> + struct iommu_dma_domain *dma_domain;
> +#endif
> #endif
> bool dma_coherent;
> };
> diff --git a/arch/arm64/include/asm/dma-mapping.h
> b/arch/arm64/include/asm/dma-mapping.h
> index 6932bb5..c1b271f 100644
> --- a/arch/arm64/include/asm/dma-mapping.h
> +++ b/arch/arm64/include/asm/dma-mapping.h
> @@ -62,13 +62,30 @@ static inline bool is_device_dma_coherent(struct device
> *dev)
>
> #include <asm-generic/dma-mapping-common.h>
>
> +#ifdef CONFIG_IOMMU_DMA
> +static inline struct iommu_dma_domain *get_dma_domain(struct device *dev)
> +{
> + return dev->archdata.dma_domain;
> +}
You use this function in patch 1, so you probably need to reorder the series
slightly.
> +static inline void set_dma_domain(struct device *dev,
> + struct iommu_dma_domain *dma_domain)
> +{
> + dev->archdata.dma_domain = dma_domain;
> +}
> +#endif
> +
> static inline dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
> {
> + if (WARN_ON(dev && get_dma_domain(dev)))
> + return DMA_ERROR_CODE;
> return (dma_addr_t)paddr;
> }
>
> static inline phys_addr_t dma_to_phys(struct device *dev, dma_addr_t
> dev_addr)
> {
> + if (WARN_ON(dev && get_dma_domain(dev)))
> + return 0;
> return (phys_addr_t)dev_addr;
> }
>
> diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
> index 0a24b9b..28e771c 100644
> --- a/arch/arm64/mm/dma-mapping.c
> +++ b/arch/arm64/mm/dma-mapping.c
> @@ -23,6 +23,7 @@
> #include <linux/genalloc.h>
> #include <linux/dma-mapping.h>
> #include <linux/dma-contiguous.h>
> +#include <linux/dma-iommu.h>
> #include <linux/vmalloc.h>
> #include <linux/swiotlb.h>
>
> @@ -426,6 +427,7 @@ static int __init arm64_dma_init(void)
>
> ret |= swiotlb_late_init();
> ret |= atomic_pool_init();
> + ret |= iommu_dma_init();
>
> return ret;
> }
> @@ -439,3 +441,321 @@ static int __init dma_debug_do_init(void)
> return 0;
> }
> fs_initcall(dma_debug_do_init);
> +
> +
> +#ifdef CONFIG_IOMMU_DMA
> +
> +static struct page **__atomic_get_pages(void *addr)
> +{
> + struct page *page;
> + phys_addr_t phys;
> +
> + phys = gen_pool_virt_to_phys(atomic_pool, (unsigned long)addr);
> + page = phys_to_page(phys);
> +
> + return (struct page **)page;
> +}
> +
> +static struct page **__iommu_get_pages(void *cpu_addr, struct dma_attrs
> *attrs)
> +{
> + struct vm_struct *area;
> +
> + if (__in_atomic_pool(cpu_addr, PAGE_SIZE))
> + return __atomic_get_pages(cpu_addr);
> +
> + area = find_vm_area(cpu_addr);
> + if (!area)
> + return NULL;
> +
> + return area->pages;
> +}
> +
> +static void *__iommu_alloc_atomic(struct device *dev, size_t size,
> + dma_addr_t *handle, bool coherent)
> +{
> + struct page *page;
> + void *addr;
> +
> + addr = __alloc_from_pool(size, &page);
> + if (!addr)
> + return NULL;
> +
> + *handle = iommu_dma_create_iova_mapping(dev, &page, size, coherent);
> + if (*handle == DMA_ERROR_CODE) {
> + __free_from_pool(addr, size);
> + return NULL;
> + }
> + return addr;
> +}
> +
> +static void __iommu_free_atomic(struct device *dev, void *cpu_addr,
> + dma_addr_t handle, size_t size)
> +{
> + iommu_dma_release_iova_mapping(dev, handle, size);
> + __free_from_pool(cpu_addr, size);
> +}
Up until this point, I don't get why things need to be arch-specific. Surely
we should only care about cache and MMU management in the arch code?
> +static void __dma_clear_buffer(struct page *page, size_t size)
> +{
> + void *ptr = page_address(page);
> +
> + memset(ptr, 0, size);
> + __dma_flush_range(ptr, ptr + size);
> +}
> +
> +static void *__iommu_alloc_attrs(struct device *dev, size_t size,
> + dma_addr_t *handle, gfp_t gfp,
> + struct dma_attrs *attrs)
> +{
> + bool coherent = is_device_dma_coherent(dev);
> + pgprot_t prot = coherent ? __pgprot(PROT_NORMAL) :
> + __pgprot(PROT_NORMAL_NC);
> + struct page **pages;
> + void *addr = NULL;
> +
> + *handle = DMA_ERROR_CODE;
> + size = PAGE_ALIGN(size);
> +
> + if (!(gfp & __GFP_WAIT))
> + return __iommu_alloc_atomic(dev, size, handle, coherent);
> + /*
> + * FIXME: This isn't even true any more!
> + *
> + * Following is a work-around (a.k.a. hack) to prevent pages
> + * with __GFP_COMP being passed to split_page() which cannot
> + * handle them. The real problem is that this flag probably
> + * should be 0 on ARM as it is not supported on this
> + * platform; see CONFIG_HUGETLBFS.
> + */
> + gfp &= ~(__GFP_COMP);
We should fix this... is it not just a case of calling split_huge_page
for compond pages?
Will
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