Re: [Linaro-mm-sig] [PATCHv9 10/10] ARM: dma-mapping: add support for IOMMU mapper

[Abhinav Kochhar <kochhar.abhinav@gmail.com>]

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Hi Marek,

dma_addr_t dma_addr is an unused argument passed to the function
arm_iommu_mmap_attrs

+static int arm_iommu_mmap_attrs(struct device *dev, struct vm_area_struct
*vma,
+                   void *cpu_addr, dma_addr_t dma_addr, size_t size,
+                   struct dma_attrs *attrs)
+{
+       struct arm_vmregion *c;
+
+       vma->vm_page_prot = __get_dma_pgprot(attrs, vma->vm_page_prot);
+       c = arm_vmregion_find(&consistent_
head, (unsigned long)cpu_addr);
+
+       if (c) {
+               struct page **pages = c->priv;
+
+               unsigned long uaddr = vma->vm_start;
+               unsigned long usize = vma->vm_end - vma->vm_start;
+               int i = 0;
+
+               do {
+                       int ret;
+
+                       ret = vm_insert_page(vma, uaddr, pages[i++]);
+                       if (ret) {
+                               pr_err("Remapping memory, error: %d\n",
ret);
+                               return ret;
+                       }
+
+                       uaddr += PAGE_SIZE;
+                       usize -= PAGE_SIZE;
+               } while (usize > 0);
+       }
+       return 0;
+}


On Wed, Apr 18, 2012 at 10:44 PM, Marek Szyprowski <m.szyprowski@samsung.com
> wrote:

> This patch add a complete implementation of DMA-mapping API for
> devices which have IOMMU support.
>
> This implementation tries to optimize dma address space usage by remapping
> all possible physical memory chunks into a single dma address space chunk.
>
> DMA address space is managed on top of the bitmap stored in the
> dma_iommu_mapping structure stored in device->archdata. Platform setup
> code has to initialize parameters of the dma address space (base address,
> size, allocation precision order) with arm_iommu_create_mapping() function.
> To reduce the size of the bitmap, all allocations are aligned to the
> specified order of base 4 KiB pages.
>
> dma_alloc_* functions allocate physical memory in chunks, each with
> alloc_pages() function to avoid failing if the physical memory gets
> fragmented. In worst case the allocated buffer is composed of 4 KiB page
> chunks.
>
> dma_map_sg() function minimizes the total number of dma address space
> chunks by merging of physical memory chunks into one larger dma address
> space chunk. If requested chunk (scatter list entry) boundaries
> match physical page boundaries, most calls to dma_map_sg() requests will
> result in creating only one chunk in dma address space.
>
> dma_map_page() simply creates a mapping for the given page(s) in the dma
> address space.
>
> All dma functions also perform required cache operation like their
> counterparts from the arm linear physical memory mapping version.
>
> This patch contains code and fixes kindly provided by:
> - Krishna Reddy <vdumpa@nvidia.com>,
> - Andrzej Pietrasiewicz <andrzej.p@samsung.com>,
> - Hiroshi DOYU <hdoyu@nvidia.com>
>
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> Tested-By: Subash Patel <subash.ramaswamy@linaro.org>
> ---
>  arch/arm/Kconfig                 |    8 +
>  arch/arm/include/asm/device.h    |    3 +
>  arch/arm/include/asm/dma-iommu.h |   34 ++
>  arch/arm/mm/dma-mapping.c        |  727
> +++++++++++++++++++++++++++++++++++++-
>  arch/arm/mm/vmregion.h           |    2 +-
>  5 files changed, 759 insertions(+), 15 deletions(-)
>  create mode 100644 arch/arm/include/asm/dma-iommu.h
>
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index 0fd27d4..874e519 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -46,6 +46,14 @@ config ARM
>  config ARM_HAS_SG_CHAIN
>        bool
>
> +config NEED_SG_DMA_LENGTH
> +       bool
> +
> +config ARM_DMA_USE_IOMMU
> +       select NEED_SG_DMA_LENGTH
> +       select ARM_HAS_SG_CHAIN
> +       bool
> +
>  config HAVE_PWM
>        bool
>
> diff --git a/arch/arm/include/asm/device.h b/arch/arm/include/asm/device.h
> index 6e2cb0e..b69c0d3 100644
> --- a/arch/arm/include/asm/device.h
> +++ b/arch/arm/include/asm/device.h
> @@ -14,6 +14,9 @@ struct dev_archdata {
>  #ifdef CONFIG_IOMMU_API
>        void *iommu; /* private IOMMU data */
>  #endif
> +#ifdef CONFIG_ARM_DMA_USE_IOMMU
> +       struct dma_iommu_mapping        *mapping;
> +#endif
>  };
>
>  struct omap_device;
> diff --git a/arch/arm/include/asm/dma-iommu.h
> b/arch/arm/include/asm/dma-iommu.h
> new file mode 100644
> index 0000000..799b094
> --- /dev/null
> +++ b/arch/arm/include/asm/dma-iommu.h
> @@ -0,0 +1,34 @@
> +#ifndef ASMARM_DMA_IOMMU_H
> +#define ASMARM_DMA_IOMMU_H
> +
> +#ifdef __KERNEL__
> +
> +#include <linux/mm_types.h>
> +#include <linux/scatterlist.h>
> +#include <linux/dma-debug.h>
> +#include <linux/kmemcheck.h>
> +
> +struct dma_iommu_mapping {
> +       /* iommu specific data */
> +       struct iommu_domain     *domain;
> +
> +       void                    *bitmap;
> +       size_t                  bits;
> +       unsigned int            order;
> +       dma_addr_t              base;
> +
> +       spinlock_t              lock;
> +       struct kref             kref;
> +};
> +
> +struct dma_iommu_mapping *
> +arm_iommu_create_mapping(struct bus_type *bus, dma_addr_t base, size_t
> size,
> +                        int order);
> +
> +void arm_iommu_release_mapping(struct dma_iommu_mapping *mapping);
> +
> +int arm_iommu_attach_device(struct device *dev,
> +                                       struct dma_iommu_mapping *mapping);
> +
> +#endif /* __KERNEL__ */
> +#endif
> diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
> index d4aad65..2d11aa0 100644
> --- a/arch/arm/mm/dma-mapping.c
> +++ b/arch/arm/mm/dma-mapping.c
> @@ -19,6 +19,8 @@
>  #include <linux/dma-mapping.h>
>  #include <linux/highmem.h>
>  #include <linux/slab.h>
> +#include <linux/iommu.h>
> +#include <linux/vmalloc.h>
>
>  #include <asm/memory.h>
>  #include <asm/highmem.h>
> @@ -26,6 +28,7 @@
>  #include <asm/tlbflush.h>
>  #include <asm/sizes.h>
>  #include <asm/mach/arch.h>
> +#include <asm/dma-iommu.h>
>
>  #include "mm.h"
>
> @@ -155,6 +158,21 @@ static u64 get_coherent_dma_mask(struct device *dev)
>        return mask;
>  }
>
> +static void __dma_clear_buffer(struct page *page, size_t size)
> +{
> +       void *ptr;
> +       /*
> +        * Ensure that the allocated pages are zeroed, and that any data
> +        * lurking in the kernel direct-mapped region is invalidated.
> +        */
> +       ptr = page_address(page);
> +       if (ptr) {
> +               memset(ptr, 0, size);
> +               dmac_flush_range(ptr, ptr + size);
> +               outer_flush_range(__pa(ptr), __pa(ptr) + size);
> +       }
> +}
> +
>  /*
>  * Allocate a DMA buffer for 'dev' of size 'size' using the
>  * specified gfp mask.  Note that 'size' must be page aligned.
> @@ -163,7 +181,6 @@ static struct page *__dma_alloc_buffer(struct device
> *dev, size_t size, gfp_t gf
>  {
>        unsigned long order = get_order(size);
>        struct page *page, *p, *e;
> -       void *ptr;
>        u64 mask = get_coherent_dma_mask(dev);
>
>  #ifdef CONFIG_DMA_API_DEBUG
> @@ -192,14 +209,7 @@ static struct page *__dma_alloc_buffer(struct device
> *dev, size_t size, gfp_t gf
>        for (p = page + (size >> PAGE_SHIFT), e = page + (1 << order); p <
> e; p++)
>                __free_page(p);
>
> -       /*
> -        * Ensure that the allocated pages are zeroed, and that any data
> -        * lurking in the kernel direct-mapped region is invalidated.
> -        */
> -       ptr = page_address(page);
> -       memset(ptr, 0, size);
> -       dmac_flush_range(ptr, ptr + size);
> -       outer_flush_range(__pa(ptr), __pa(ptr) + size);
> +       __dma_clear_buffer(page, size);
>
>        return page;
>  }
> @@ -348,7 +358,7 @@ __dma_alloc_remap(struct page *page, size_t size,
> gfp_t gfp, pgprot_t prot,
>                u32 off = CONSISTENT_OFFSET(c->vm_start) & (PTRS_PER_PTE-1);
>
>                pte = consistent_pte[idx] + off;
> -               c->vm_pages = page;
> +               c->priv = page;
>
>                do {
>                        BUG_ON(!pte_none(*pte));
> @@ -461,6 +471,14 @@ __dma_alloc(struct device *dev, size_t size,
> dma_addr_t *handle, gfp_t gfp,
>        return addr;
>  }
>
> +static inline pgprot_t __get_dma_pgprot(struct dma_attrs *attrs, pgprot_t
> prot)
> +{
> +       prot = dma_get_attr(DMA_ATTR_WRITE_COMBINE, attrs) ?
> +                           pgprot_writecombine(prot) :
> +                           pgprot_dmacoherent(prot);
> +       return prot;
> +}
> +
>  /*
>  * Allocate DMA-coherent memory space and return both the kernel remapped
>  * virtual and bus address for that space.
> @@ -468,9 +486,7 @@ __dma_alloc(struct device *dev, size_t size,
> dma_addr_t *handle, gfp_t gfp,
>  void *arm_dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,
>                    gfp_t gfp, struct dma_attrs *attrs)
>  {
> -       pgprot_t prot = dma_get_attr(DMA_ATTR_WRITE_COMBINE, attrs) ?
> -                       pgprot_writecombine(pgprot_kernel) :
> -                       pgprot_dmacoherent(pgprot_kernel);
> +       pgprot_t prot = __get_dma_pgprot(attrs, pgprot_kernel);
>        void *memory;
>
>        if (dma_alloc_from_coherent(dev, size, handle, &memory))
> @@ -497,16 +513,20 @@ int arm_dma_mmap(struct device *dev, struct
> vm_area_struct *vma,
>                            pgprot_writecombine(vma->vm_page_prot) :
>                            pgprot_dmacoherent(vma->vm_page_prot);
>
> +       if (dma_mmap_from_coherent(dev, vma, cpu_addr, size, &ret))
> +               return ret;
> +
>        c = arm_vmregion_find(&consistent_head, (unsigned long)cpu_addr);
>        if (c) {
>                unsigned long off = vma->vm_pgoff;
> +               struct page *pages = c->priv;
>
>                kern_size = (c->vm_end - c->vm_start) >> PAGE_SHIFT;
>
>                if (off < kern_size &&
>                    user_size <= (kern_size - off)) {
>                        ret = remap_pfn_range(vma, vma->vm_start,
> -                                             page_to_pfn(c->vm_pages) +
> off,
> +                                             page_to_pfn(pages) + off,
>                                              user_size << PAGE_SHIFT,
>                                              vma->vm_page_prot);
>                }
> @@ -645,6 +665,9 @@ int arm_dma_map_sg(struct device *dev, struct
> scatterlist *sg, int nents,
>        int i, j;
>
>        for_each_sg(sg, s, nents, i) {
> +#ifdef CONFIG_NEED_SG_DMA_LENGTH
> +               s->dma_length = s->length;
> +#endif
>                s->dma_address = ops->map_page(dev, sg_page(s), s->offset,
>                                                s->length, dir, attrs);
>                if (dma_mapping_error(dev, s->dma_address))
> @@ -753,3 +776,679 @@ static int __init dma_debug_do_init(void)
>        return 0;
>  }
>  fs_initcall(dma_debug_do_init);
> +
> +#ifdef CONFIG_ARM_DMA_USE_IOMMU
> +
> +/* IOMMU */
> +
> +static inline dma_addr_t __alloc_iova(struct dma_iommu_mapping *mapping,
> +                                     size_t size)
> +{
> +       unsigned int order = get_order(size);
> +       unsigned int align = 0;
> +       unsigned int count, start;
> +       unsigned long flags;
> +
> +       count = ((PAGE_ALIGN(size) >> PAGE_SHIFT) +
> +                (1 << mapping->order) - 1) >> mapping->order;
> +
> +       if (order > mapping->order)
> +               align = (1 << (order - mapping->order)) - 1;
> +
> +       spin_lock_irqsave(&mapping->lock, flags);
> +       start = bitmap_find_next_zero_area(mapping->bitmap, mapping->bits,
> 0,
> +                                          count, align);
> +       if (start > mapping->bits) {
> +               spin_unlock_irqrestore(&mapping->lock, flags);
> +               return DMA_ERROR_CODE;
> +       }
> +
> +       bitmap_set(mapping->bitmap, start, count);
> +       spin_unlock_irqrestore(&mapping->lock, flags);
> +
> +       return mapping->base + (start << (mapping->order + PAGE_SHIFT));
> +}
> +
> +static inline void __free_iova(struct dma_iommu_mapping *mapping,
> +                              dma_addr_t addr, size_t size)
> +{
> +       unsigned int start = (addr - mapping->base) >>
> +                            (mapping->order + PAGE_SHIFT);
> +       unsigned int count = ((size >> PAGE_SHIFT) +
> +                             (1 << mapping->order) - 1) >> mapping->order;
> +       unsigned long flags;
> +
> +       spin_lock_irqsave(&mapping->lock, flags);
> +       bitmap_clear(mapping->bitmap, start, count);
> +       spin_unlock_irqrestore(&mapping->lock, flags);
> +}
> +
> +static struct page **__iommu_alloc_buffer(struct device *dev, size_t
> size, gfp_t gfp)
> +{
> +       struct page **pages;
> +       int count = size >> PAGE_SHIFT;
> +       int array_size = count * sizeof(struct page *);
> +       int i = 0;
> +
> +       if (array_size <= PAGE_SIZE)
> +               pages = kzalloc(array_size, gfp);
> +       else
> +               pages = vzalloc(array_size);
> +       if (!pages)
> +               return NULL;
> +
> +       while (count) {
> +               int j, order = __ffs(count);
> +
> +               pages[i] = alloc_pages(gfp | __GFP_NOWARN, order);
> +               while (!pages[i] && order)
> +                       pages[i] = alloc_pages(gfp | __GFP_NOWARN,
> --order);
> +               if (!pages[i])
> +                       goto error;
> +
> +               if (order)
> +                       split_page(pages[i], order);
> +               j = 1 << order;
> +               while (--j)
> +                       pages[i + j] = pages[i] + j;
> +
> +               __dma_clear_buffer(pages[i], PAGE_SIZE << order);
> +               i += 1 << order;
> +               count -= 1 << order;
> +       }
> +
> +       return pages;
> +error:
> +       while (--i)
> +               if (pages[i])
> +                       __free_pages(pages[i], 0);
> +       if (array_size < PAGE_SIZE)
> +               kfree(pages);
> +       else
> +               vfree(pages);
> +       return NULL;
> +}
> +
> +static int __iommu_free_buffer(struct device *dev, struct page **pages,
> size_t size)
> +{
> +       int count = size >> PAGE_SHIFT;
> +       int array_size = count * sizeof(struct page *);
> +       int i;
> +       for (i = 0; i < count; i++)
> +               if (pages[i])
> +                       __free_pages(pages[i], 0);
> +       if (array_size < PAGE_SIZE)
> +               kfree(pages);
> +       else
> +               vfree(pages);
> +       return 0;
> +}
> +
> +/*
> + * Create a CPU mapping for a specified pages
> + */
> +static void *
> +__iommu_alloc_remap(struct page **pages, size_t size, gfp_t gfp, pgprot_t
> prot)
> +{
> +       struct arm_vmregion *c;
> +       size_t align;
> +       size_t count = size >> PAGE_SHIFT;
> +       int bit;
> +
> +       if (!consistent_pte[0]) {
> +               pr_err("%s: not initialised\n", __func__);
> +               dump_stack();
> +               return NULL;
> +       }
> +
> +       /*
> +        * Align the virtual region allocation - maximum alignment is
> +        * a section size, minimum is a page size.  This helps reduce
> +        * fragmentation of the DMA space, and also prevents allocations
> +        * smaller than a section from crossing a section boundary.
> +        */
> +       bit = fls(size - 1);
> +       if (bit > SECTION_SHIFT)
> +               bit = SECTION_SHIFT;
> +       align = 1 << bit;
> +
> +       /*
> +        * Allocate a virtual address in the consistent mapping region.
> +        */
> +       c = arm_vmregion_alloc(&consistent_head, align, size,
> +                           gfp & ~(__GFP_DMA | __GFP_HIGHMEM), NULL);
> +       if (c) {
> +               pte_t *pte;
> +               int idx = CONSISTENT_PTE_INDEX(c->vm_start);
> +               int i = 0;
> +               u32 off = CONSISTENT_OFFSET(c->vm_start) &
> (PTRS_PER_PTE-1);
> +
> +               pte = consistent_pte[idx] + off;
> +               c->priv = pages;
> +
> +               do {
> +                       BUG_ON(!pte_none(*pte));
> +
> +                       set_pte_ext(pte, mk_pte(pages[i], prot), 0);
> +                       pte++;
> +                       off++;
> +                       i++;
> +                       if (off >= PTRS_PER_PTE) {
> +                               off = 0;
> +                               pte = consistent_pte[++idx];
> +                       }
> +               } while (i < count);
> +
> +               dsb();
> +
> +               return (void *)c->vm_start;
> +       }
> +       return NULL;
> +}
> +
> +/*
> + * Create a mapping in device IO address space for specified pages
> + */
> +static dma_addr_t
> +__iommu_create_mapping(struct device *dev, struct page **pages, size_t
> size)
> +{
> +       struct dma_iommu_mapping *mapping = dev->archdata.mapping;
> +       unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
> +       dma_addr_t dma_addr, iova;
> +       int i, ret = DMA_ERROR_CODE;
> +
> +       dma_addr = __alloc_iova(mapping, size);
> +       if (dma_addr == DMA_ERROR_CODE)
> +               return dma_addr;
> +
> +       iova = dma_addr;
> +       for (i = 0; i < count; ) {
> +               unsigned int next_pfn = page_to_pfn(pages[i]) + 1;
> +               phys_addr_t phys = page_to_phys(pages[i]);
> +               unsigned int len, j;
> +
> +               for (j = i + 1; j < count; j++, next_pfn++)
> +                       if (page_to_pfn(pages[j]) != next_pfn)
> +                               break;
> +
> +               len = (j - i) << PAGE_SHIFT;
> +               ret = iommu_map(mapping->domain, iova, phys, len, 0);
> +               if (ret < 0)
> +                       goto fail;
> +               iova += len;
> +               i = j;
> +       }
> +       return dma_addr;
> +fail:
> +       iommu_unmap(mapping->domain, dma_addr, iova-dma_addr);
> +       __free_iova(mapping, dma_addr, size);
> +       return DMA_ERROR_CODE;
> +}
> +
> +static int __iommu_remove_mapping(struct device *dev, dma_addr_t iova,
> size_t size)
> +{
> +       struct dma_iommu_mapping *mapping = dev->archdata.mapping;
> +
> +       /*
> +        * add optional in-page offset from iova to size and align
> +        * result to page size
> +        */
> +       size = PAGE_ALIGN((iova & ~PAGE_MASK) + size);
> +       iova &= PAGE_MASK;
> +
> +       iommu_unmap(mapping->domain, iova, size);
> +       __free_iova(mapping, iova, size);
> +       return 0;
> +}
> +
> +static void *arm_iommu_alloc_attrs(struct device *dev, size_t size,
> +           dma_addr_t *handle, gfp_t gfp, struct dma_attrs *attrs)
> +{
> +       pgprot_t prot = __get_dma_pgprot(attrs, pgprot_kernel);
> +       struct page **pages;
> +       void *addr = NULL;
> +
> +       *handle = DMA_ERROR_CODE;
> +       size = PAGE_ALIGN(size);
> +
> +       pages = __iommu_alloc_buffer(dev, size, gfp);
> +       if (!pages)
> +               return NULL;
> +
> +       *handle = __iommu_create_mapping(dev, pages, size);
> +       if (*handle == DMA_ERROR_CODE)
> +               goto err_buffer;
> +
> +       addr = __iommu_alloc_remap(pages, size, gfp, prot);
> +       if (!addr)
> +               goto err_mapping;
> +
> +       return addr;
> +
> +err_mapping:
> +       __iommu_remove_mapping(dev, *handle, size);
> +err_buffer:
> +       __iommu_free_buffer(dev, pages, size);
> +       return NULL;
> +}
> +
> +static int arm_iommu_mmap_attrs(struct device *dev, struct vm_area_struct
> *vma,
> +                   void *cpu_addr, dma_addr_t dma_addr, size_t size,
> +                   struct dma_attrs *attrs)
> +{
> +       struct arm_vmregion *c;
> +
> +       vma->vm_page_prot = __get_dma_pgprot(attrs, vma->vm_page_prot);
> +       c = arm_vmregion_find(&consistent_head, (unsigned long)cpu_addr);
> +
> +       if (c) {
> +               struct page **pages = c->priv;
> +
> +               unsigned long uaddr = vma->vm_start;
> +               unsigned long usize = vma->vm_end - vma->vm_start;
> +               int i = 0;
> +
> +               do {
> +                       int ret;
> +
> +                       ret = vm_insert_page(vma, uaddr, pages[i++]);
> +                       if (ret) {
> +                               pr_err("Remapping memory, error: %d\n",
> ret);
> +                               return ret;
> +                       }
> +
> +                       uaddr += PAGE_SIZE;
> +                       usize -= PAGE_SIZE;
> +               } while (usize > 0);
> +       }
> +       return 0;
> +}
> +
> +/*
> + * free a page as defined by the above mapping.
> + * Must not be called with IRQs disabled.
> + */
> +void arm_iommu_free_attrs(struct device *dev, size_t size, void *cpu_addr,
> +                         dma_addr_t handle, struct dma_attrs *attrs)
> +{
> +       struct arm_vmregion *c;
> +       size = PAGE_ALIGN(size);
> +
> +       c = arm_vmregion_find(&consistent_head, (unsigned long)cpu_addr);
> +       if (c) {
> +               struct page **pages = c->priv;
> +               __dma_free_remap(cpu_addr, size);
> +               __iommu_remove_mapping(dev, handle, size);
> +               __iommu_free_buffer(dev, pages, size);
> +       }
> +}
> +
> +/*
> + * Map a part of the scatter-gather list into contiguous io address space
> + */
> +static int __map_sg_chunk(struct device *dev, struct scatterlist *sg,
> +                         size_t size, dma_addr_t *handle,
> +                         enum dma_data_direction dir)
> +{
> +       struct dma_iommu_mapping *mapping = dev->archdata.mapping;
> +       dma_addr_t iova, iova_base;
> +       int ret = 0;
> +       unsigned int count;
> +       struct scatterlist *s;
> +
> +       size = PAGE_ALIGN(size);
> +       *handle = DMA_ERROR_CODE;
> +
> +       iova_base = iova = __alloc_iova(mapping, size);
> +       if (iova == DMA_ERROR_CODE)
> +               return -ENOMEM;
> +
> +       for (count = 0, s = sg; count < (size >> PAGE_SHIFT); s =
> sg_next(s)) {
> +               phys_addr_t phys = page_to_phys(sg_page(s));
> +               unsigned int len = PAGE_ALIGN(s->offset + s->length);
> +
> +               if (!arch_is_coherent())
> +                       __dma_page_cpu_to_dev(sg_page(s), s->offset,
> s->length, dir);
> +
> +               ret = iommu_map(mapping->domain, iova, phys, len, 0);
> +               if (ret < 0)
> +                       goto fail;
> +               count += len >> PAGE_SHIFT;
> +               iova += len;
> +       }
> +       *handle = iova_base;
> +
> +       return 0;
> +fail:
> +       iommu_unmap(mapping->domain, iova_base, count * PAGE_SIZE);
> +       __free_iova(mapping, iova_base, size);
> +       return ret;
> +}
> +
> +/**
> + * arm_iommu_map_sg - map a set of SG buffers for streaming mode DMA
> + * @dev: valid struct device pointer
> + * @sg: list of buffers
> + * @nents: number of buffers to map
> + * @dir: DMA transfer direction
> + *
> + * Map a set of buffers described by scatterlist in streaming mode for
> DMA.
> + * The scatter gather list elements are merged together (if possible) and
> + * tagged with the appropriate dma address and length. They are obtained
> via
> + * sg_dma_{address,length}.
> + */
> +int arm_iommu_map_sg(struct device *dev, struct scatterlist *sg, int
> nents,
> +                    enum dma_data_direction dir, struct dma_attrs *attrs)
> +{
> +       struct scatterlist *s = sg, *dma = sg, *start = sg;
> +       int i, count = 0;
> +       unsigned int offset = s->offset;
> +       unsigned int size = s->offset + s->length;
> +       unsigned int max = dma_get_max_seg_size(dev);
> +
> +       for (i = 1; i < nents; i++) {
> +               s = sg_next(s);
> +
> +               s->dma_address = DMA_ERROR_CODE;
> +               s->dma_length = 0;
> +
> +               if (s->offset || (size & ~PAGE_MASK) || size + s->length >
> max) {
> +                       if (__map_sg_chunk(dev, start, size,
> &dma->dma_address,
> +                           dir) < 0)
> +                               goto bad_mapping;
> +
> +                       dma->dma_address += offset;
> +                       dma->dma_length = size - offset;
> +
> +                       size = offset = s->offset;
> +                       start = s;
> +                       dma = sg_next(dma);
> +                       count += 1;
> +               }
> +               size += s->length;
> +       }
> +       if (__map_sg_chunk(dev, start, size, &dma->dma_address, dir) < 0)
> +               goto bad_mapping;
> +
> +       dma->dma_address += offset;
> +       dma->dma_length = size - offset;
> +
> +       return count+1;
> +
> +bad_mapping:
> +       for_each_sg(sg, s, count, i)
> +               __iommu_remove_mapping(dev, sg_dma_address(s),
> sg_dma_len(s));
> +       return 0;
> +}
> +
> +/**
> + * arm_iommu_unmap_sg - unmap a set of SG buffers mapped by dma_map_sg
> + * @dev: valid struct device pointer
> + * @sg: list of buffers
> + * @nents: number of buffers to unmap (same as was passed to dma_map_sg)
> + * @dir: DMA transfer direction (same as was passed to dma_map_sg)
> + *
> + * Unmap a set of streaming mode DMA translations.  Again, CPU access
> + * rules concerning calls here are the same as for dma_unmap_single().
> + */
> +void arm_iommu_unmap_sg(struct device *dev, struct scatterlist *sg, int
> nents,
> +                       enum dma_data_direction dir, struct dma_attrs
> *attrs)
> +{
> +       struct scatterlist *s;
> +       int i;
> +
> +       for_each_sg(sg, s, nents, i) {
> +               if (sg_dma_len(s))
> +                       __iommu_remove_mapping(dev, sg_dma_address(s),
> +                                              sg_dma_len(s));
> +               if (!arch_is_coherent())
> +                       __dma_page_dev_to_cpu(sg_page(s), s->offset,
> +                                             s->length, dir);
> +       }
> +}
> +
> +/**
> + * arm_iommu_sync_sg_for_cpu
> + * @dev: valid struct device pointer
> + * @sg: list of buffers
> + * @nents: number of buffers to map (returned from dma_map_sg)
> + * @dir: DMA transfer direction (same as was passed to dma_map_sg)
> + */
> +void arm_iommu_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
> +                       int nents, enum dma_data_direction dir)
> +{
> +       struct scatterlist *s;
> +       int i;
> +
> +       for_each_sg(sg, s, nents, i)
> +               if (!arch_is_coherent())
> +                       __dma_page_dev_to_cpu(sg_page(s), s->offset,
> s->length, dir);
> +
> +}
> +
> +/**
> + * arm_iommu_sync_sg_for_device
> + * @dev: valid struct device pointer
> + * @sg: list of buffers
> + * @nents: number of buffers to map (returned from dma_map_sg)
> + * @dir: DMA transfer direction (same as was passed to dma_map_sg)
> + */
> +void arm_iommu_sync_sg_for_device(struct device *dev, struct scatterlist
> *sg,
> +                       int nents, enum dma_data_direction dir)
> +{
> +       struct scatterlist *s;
> +       int i;
> +
> +       for_each_sg(sg, s, nents, i)
> +               if (!arch_is_coherent())
> +                       __dma_page_cpu_to_dev(sg_page(s), s->offset,
> s->length, dir);
> +}
> +
> +
> +/**
> + * arm_iommu_map_page
> + * @dev: valid struct device pointer
> + * @page: page that buffer resides in
> + * @offset: offset into page for start of buffer
> + * @size: size of buffer to map
> + * @dir: DMA transfer direction
> + *
> + * IOMMU aware version of arm_dma_map_page()
> + */
> +static dma_addr_t arm_iommu_map_page(struct device *dev, struct page
> *page,
> +            unsigned long offset, size_t size, enum dma_data_direction
> dir,
> +            struct dma_attrs *attrs)
> +{
> +       struct dma_iommu_mapping *mapping = dev->archdata.mapping;
> +       dma_addr_t dma_addr;
> +       int ret, len = PAGE_ALIGN(size + offset);
> +
> +       if (!arch_is_coherent())
> +               __dma_page_cpu_to_dev(page, offset, size, dir);
> +
> +       dma_addr = __alloc_iova(mapping, len);
> +       if (dma_addr == DMA_ERROR_CODE)
> +               return dma_addr;
> +
> +       ret = iommu_map(mapping->domain, dma_addr, page_to_phys(page),
> len, 0);
> +       if (ret < 0)
> +               goto fail;
> +
> +       return dma_addr + offset;
> +fail:
> +       __free_iova(mapping, dma_addr, len);
> +       return DMA_ERROR_CODE;
> +}
> +
> +/**
> + * arm_iommu_unmap_page
> + * @dev: valid struct device pointer
> + * @handle: DMA address of buffer
> + * @size: size of buffer (same as passed to dma_map_page)
> + * @dir: DMA transfer direction (same as passed to dma_map_page)
> + *
> + * IOMMU aware version of arm_dma_unmap_page()
> + */
> +static void arm_iommu_unmap_page(struct device *dev, dma_addr_t handle,
> +               size_t size, enum dma_data_direction dir,
> +               struct dma_attrs *attrs)
> +{
> +       struct dma_iommu_mapping *mapping = dev->archdata.mapping;
> +       dma_addr_t iova = handle & PAGE_MASK;
> +       struct page *page =
> phys_to_page(iommu_iova_to_phys(mapping->domain, iova));
> +       int offset = handle & ~PAGE_MASK;
> +       int len = PAGE_ALIGN(size + offset);
> +
> +       if (!iova)
> +               return;
> +
> +       if (!arch_is_coherent())
> +               __dma_page_dev_to_cpu(page, offset, size, dir);
> +
> +       iommu_unmap(mapping->domain, iova, len);
> +       __free_iova(mapping, iova, len);
> +}
> +
> +static void arm_iommu_sync_single_for_cpu(struct device *dev,
> +               dma_addr_t handle, size_t size, enum dma_data_direction
> dir)
> +{
> +       struct dma_iommu_mapping *mapping = dev->archdata.mapping;
> +       dma_addr_t iova = handle & PAGE_MASK;
> +       struct page *page =
> phys_to_page(iommu_iova_to_phys(mapping->domain, iova));
> +       unsigned int offset = handle & ~PAGE_MASK;
> +
> +       if (!iova)
> +               return;
> +
> +       if (!arch_is_coherent())
> +               __dma_page_dev_to_cpu(page, offset, size, dir);
> +}
> +
> +static void arm_iommu_sync_single_for_device(struct device *dev,
> +               dma_addr_t handle, size_t size, enum dma_data_direction
> dir)
> +{
> +       struct dma_iommu_mapping *mapping = dev->archdata.mapping;
> +       dma_addr_t iova = handle & PAGE_MASK;
> +       struct page *page =
> phys_to_page(iommu_iova_to_phys(mapping->domain, iova));
> +       unsigned int offset = handle & ~PAGE_MASK;
> +
> +       if (!iova)
> +               return;
> +
> +       __dma_page_cpu_to_dev(page, offset, size, dir);
> +}
> +
> +struct dma_map_ops iommu_ops = {
> +       .alloc          = arm_iommu_alloc_attrs,
> +       .free           = arm_iommu_free_attrs,
> +       .mmap           = arm_iommu_mmap_attrs,
> +
> +       .map_page               = arm_iommu_map_page,
> +       .unmap_page             = arm_iommu_unmap_page,
> +       .sync_single_for_cpu    = arm_iommu_sync_single_for_cpu,
> +       .sync_single_for_device = arm_iommu_sync_single_for_device,
> +
> +       .map_sg                 = arm_iommu_map_sg,
> +       .unmap_sg               = arm_iommu_unmap_sg,
> +       .sync_sg_for_cpu        = arm_iommu_sync_sg_for_cpu,
> +       .sync_sg_for_device     = arm_iommu_sync_sg_for_device,
> +};
> +
> +/**
> + * arm_iommu_create_mapping
> + * @bus: pointer to the bus holding the client device (for IOMMU calls)
> + * @base: start address of the valid IO address space
> + * @size: size of the valid IO address space
> + * @order: accuracy of the IO addresses allocations
> + *
> + * Creates a mapping structure which holds information about used/unused
> + * IO address ranges, which is required to perform memory allocation and
> + * mapping with IOMMU aware functions.
> + *
> + * The client device need to be attached to the mapping with
> + * arm_iommu_attach_device function.
> + */
> +struct dma_iommu_mapping *
> +arm_iommu_create_mapping(struct bus_type *bus, dma_addr_t base, size_t
> size,
> +                        int order)
> +{
> +       unsigned int count = size >> (PAGE_SHIFT + order);
> +       unsigned int bitmap_size = BITS_TO_LONGS(count) * sizeof(long);
> +       struct dma_iommu_mapping *mapping;
> +       int err = -ENOMEM;
> +
> +       if (!count)
> +               return ERR_PTR(-EINVAL);
> +
> +       mapping = kzalloc(sizeof(struct dma_iommu_mapping), GFP_KERNEL);
> +       if (!mapping)
> +               goto err;
> +
> +       mapping->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
> +       if (!mapping->bitmap)
> +               goto err2;
> +
> +       mapping->base = base;
> +       mapping->bits = BITS_PER_BYTE * bitmap_size;
> +       mapping->order = order;
> +       spin_lock_init(&mapping->lock);
> +
> +       mapping->domain = iommu_domain_alloc(bus);
> +       if (!mapping->domain)
> +               goto err3;
> +
> +       kref_init(&mapping->kref);
> +       return mapping;
> +err3:
> +       kfree(mapping->bitmap);
> +err2:
> +       kfree(mapping);
> +err:
> +       return ERR_PTR(err);
> +}
> +
> +static void release_iommu_mapping(struct kref *kref)
> +{
> +       struct dma_iommu_mapping *mapping =
> +               container_of(kref, struct dma_iommu_mapping, kref);
> +
> +       iommu_domain_free(mapping->domain);
> +       kfree(mapping->bitmap);
> +       kfree(mapping);
> +}
> +
> +void arm_iommu_release_mapping(struct dma_iommu_mapping *mapping)
> +{
> +       if (mapping)
> +               kref_put(&mapping->kref, release_iommu_mapping);
> +}
> +
> +/**
> + * arm_iommu_attach_device
> + * @dev: valid struct device pointer
> + * @mapping: io address space mapping structure (returned from
> + *     arm_iommu_create_mapping)
> + *
> + * Attaches specified io address space mapping to the provided device,
> + * this replaces the dma operations (dma_map_ops pointer) with the
> + * IOMMU aware version. More than one client might be attached to
> + * the same io address space mapping.
> + */
> +int arm_iommu_attach_device(struct device *dev,
> +                           struct dma_iommu_mapping *mapping)
> +{
> +       int err;
> +
> +       err = iommu_attach_device(mapping->domain, dev);
> +       if (err)
> +               return err;
> +
> +       kref_get(&mapping->kref);
> +       dev->archdata.mapping = mapping;
> +       set_dma_ops(dev, &iommu_ops);
> +
> +       pr_info("Attached IOMMU controller to %s device.\n",
> dev_name(dev));
> +       return 0;
> +}
> +
> +#endif
> diff --git a/arch/arm/mm/vmregion.h b/arch/arm/mm/vmregion.h
> index 162be66..bf312c3 100644
> --- a/arch/arm/mm/vmregion.h
> +++ b/arch/arm/mm/vmregion.h
> @@ -17,7 +17,7 @@ struct arm_vmregion {
>        struct list_head        vm_list;
>        unsigned long           vm_start;
>        unsigned long           vm_end;
> -       struct page             *vm_pages;
> +       void                    *priv;
>        int                     vm_active;
>        const void              *caller;
>  };
> --
> 1.7.1.569.g6f426
>
>
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> Linaro-mm-sig@lists.linaro.org
> http://lists.linaro.org/mailman/listinfo/linaro-mm-sig
>

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