There is nothing really arm64 specific in the iommu_dma_ops
implementation, so move it to dma-iommu.c and keep a lot of symbols
self-contained.  Note the implementation does depend on the
DMA_DIRECT_REMAP infrastructure for now, so we'll have to make the
DMA_IOMMU support depend on it, but this will be relaxed soon.

Signed-off-by: Christoph Hellwig <h...@lst.de>
---
 arch/arm64/mm/dma-mapping.c | 389 +-----------------------------------
 drivers/iommu/Kconfig       |   1 +
 drivers/iommu/dma-iommu.c   | 383 ++++++++++++++++++++++++++++++++---
 include/linux/dma-iommu.h   |  44 +---
 4 files changed, 365 insertions(+), 452 deletions(-)

diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
index 54787a3d4ad9..bf49e982c978 100644
--- a/arch/arm64/mm/dma-mapping.c
+++ b/arch/arm64/mm/dma-mapping.c
@@ -27,6 +27,7 @@
 #include <linux/dma-direct.h>
 #include <linux/dma-noncoherent.h>
 #include <linux/dma-contiguous.h>
+#include <linux/dma-iommu.h>
 #include <linux/vmalloc.h>
 #include <linux/swiotlb.h>
 #include <linux/pci.h>
@@ -58,27 +59,6 @@ void arch_dma_prep_coherent(struct page *page, size_t size)
        __dma_flush_area(page_address(page), size);
 }
 
-#ifdef CONFIG_IOMMU_DMA
-static int __swiotlb_get_sgtable_page(struct sg_table *sgt,
-                                     struct page *page, size_t size)
-{
-       int ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
-
-       if (!ret)
-               sg_set_page(sgt->sgl, page, PAGE_ALIGN(size), 0);
-
-       return ret;
-}
-
-static int __swiotlb_mmap_pfn(struct vm_area_struct *vma,
-                             unsigned long pfn, size_t size)
-{
-       return remap_pfn_range(vma, vma->vm_start, pfn + vma->vm_pgoff,
-                             vma->vm_end - vma->vm_start,
-                             vma->vm_page_prot);
-}
-#endif /* CONFIG_IOMMU_DMA */
-
 static int __init arm64_dma_init(void)
 {
        WARN_TAINT(ARCH_DMA_MINALIGN < cache_line_size(),
@@ -90,379 +70,18 @@ static int __init arm64_dma_init(void)
 arch_initcall(arm64_dma_init);
 
 #ifdef CONFIG_IOMMU_DMA
-#include <linux/dma-iommu.h>
-#include <linux/platform_device.h>
-#include <linux/amba/bus.h>
-
-static void *__iommu_alloc_attrs(struct device *dev, size_t size,
-                                dma_addr_t *handle, gfp_t gfp,
-                                unsigned long attrs)
-{
-       bool coherent = dev_is_dma_coherent(dev);
-       int ioprot = dma_info_to_prot(DMA_BIDIRECTIONAL, coherent, attrs);
-       size_t iosize = size;
-       void *addr;
-
-       if (WARN(!dev, "cannot create IOMMU mapping for unknown device\n"))
-               return NULL;
-
-       size = PAGE_ALIGN(size);
-
-       /*
-        * Some drivers rely on this, and we probably don't want the
-        * possibility of stale kernel data being read by devices anyway.
-        */
-       gfp |= __GFP_ZERO;
-
-       if (!gfpflags_allow_blocking(gfp)) {
-               struct page *page;
-               /*
-                * In atomic context we can't remap anything, so we'll only
-                * get the virtually contiguous buffer we need by way of a
-                * physically contiguous allocation.
-                */
-               if (coherent) {
-                       page = alloc_pages(gfp, get_order(size));
-                       addr = page ? page_address(page) : NULL;
-               } else {
-                       addr = dma_alloc_from_pool(size, &page, gfp);
-               }
-               if (!addr)
-                       return NULL;
-
-               *handle = iommu_dma_map_page(dev, page, 0, iosize, ioprot);
-               if (*handle == DMA_MAPPING_ERROR) {
-                       if (coherent)
-                               __free_pages(page, get_order(size));
-                       else
-                               dma_free_from_pool(addr, size);
-                       addr = NULL;
-               }
-       } else if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {
-               pgprot_t prot = arch_dma_mmap_pgprot(dev, PAGE_KERNEL, attrs);
-               struct page *page;
-
-               page = dma_alloc_from_contiguous(dev, size >> PAGE_SHIFT,
-                                       get_order(size), gfp & __GFP_NOWARN);
-               if (!page)
-                       return NULL;
-
-               *handle = iommu_dma_map_page(dev, page, 0, iosize, ioprot);
-               if (*handle == DMA_MAPPING_ERROR) {
-                       dma_release_from_contiguous(dev, page,
-                                                   size >> PAGE_SHIFT);
-                       return NULL;
-               }
-               addr = dma_common_contiguous_remap(page, size, VM_USERMAP,
-                                                  prot,
-                                                  __builtin_return_address(0));
-               if (addr) {
-                       if (!coherent)
-                               __dma_flush_area(page_to_virt(page), iosize);
-                       memset(addr, 0, size);
-               } else {
-                       iommu_dma_unmap_page(dev, *handle, iosize, 0, attrs);
-                       dma_release_from_contiguous(dev, page,
-                                                   size >> PAGE_SHIFT);
-               }
-       } else {
-               pgprot_t prot = arch_dma_mmap_pgprot(dev, PAGE_KERNEL, attrs);
-               struct page **pages;
-
-               pages = iommu_dma_alloc(dev, iosize, gfp, attrs, ioprot,
-                                       handle);
-               if (!pages)
-                       return NULL;
-
-               addr = dma_common_pages_remap(pages, size, VM_USERMAP, prot,
-                                             __builtin_return_address(0));
-               if (!addr)
-                       iommu_dma_free(dev, pages, iosize, handle);
-       }
-       return addr;
-}
-
-static void __iommu_free_attrs(struct device *dev, size_t size, void *cpu_addr,
-                              dma_addr_t handle, unsigned long attrs)
-{
-       size_t iosize = size;
-
-       size = PAGE_ALIGN(size);
-       /*
-        * @cpu_addr will be one of 4 things depending on how it was allocated:
-        * - A remapped array of pages for contiguous allocations.
-        * - A remapped array of pages from iommu_dma_alloc(), for all
-        *   non-atomic allocations.
-        * - A non-cacheable alias from the atomic pool, for atomic
-        *   allocations by non-coherent devices.
-        * - A normal lowmem address, for atomic allocations by
-        *   coherent devices.
-        * Hence how dodgy the below logic looks...
-        */
-       if (dma_in_atomic_pool(cpu_addr, size)) {
-               iommu_dma_unmap_page(dev, handle, iosize, 0, 0);
-               dma_free_from_pool(cpu_addr, size);
-       } else if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {
-               struct page *page = vmalloc_to_page(cpu_addr);
-
-               iommu_dma_unmap_page(dev, handle, iosize, 0, attrs);
-               dma_release_from_contiguous(dev, page, size >> PAGE_SHIFT);
-               dma_common_free_remap(cpu_addr, size, VM_USERMAP);
-       } else if (is_vmalloc_addr(cpu_addr)){
-               struct vm_struct *area = find_vm_area(cpu_addr);
-
-               if (WARN_ON(!area || !area->pages))
-                       return;
-               iommu_dma_free(dev, area->pages, iosize, &handle);
-               dma_common_free_remap(cpu_addr, size, VM_USERMAP);
-       } else {
-               iommu_dma_unmap_page(dev, handle, iosize, 0, 0);
-               __free_pages(virt_to_page(cpu_addr), get_order(size));
-       }
-}
-
-static int __iommu_mmap_attrs(struct device *dev, struct vm_area_struct *vma,
-                             void *cpu_addr, dma_addr_t dma_addr, size_t size,
-                             unsigned long attrs)
-{
-       unsigned long nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
-       unsigned long off = vma->vm_pgoff;
-       struct vm_struct *area;
-       int ret;
-
-       vma->vm_page_prot = arch_dma_mmap_pgprot(dev, vma->vm_page_prot, attrs);
-
-       if (dma_mmap_from_dev_coherent(dev, vma, cpu_addr, size, &ret))
-               return ret;
-
-       if (off >= nr_pages || vma_pages(vma) > nr_pages - off)
-               return -ENXIO;
-
-       if (!is_vmalloc_addr(cpu_addr)) {
-               unsigned long pfn = page_to_pfn(virt_to_page(cpu_addr));
-               return __swiotlb_mmap_pfn(vma, pfn, size);
-       }
-
-       if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {
-               /*
-                * DMA_ATTR_FORCE_CONTIGUOUS allocations are always remapped,
-                * hence in the vmalloc space.
-                */
-               unsigned long pfn = vmalloc_to_pfn(cpu_addr);
-               return __swiotlb_mmap_pfn(vma, pfn, size);
-       }
-
-       area = find_vm_area(cpu_addr);
-       if (WARN_ON(!area || !area->pages))
-               return -ENXIO;
-
-       return iommu_dma_mmap(area->pages, size, vma);
-}
-
-static int __iommu_get_sgtable(struct device *dev, struct sg_table *sgt,
-                              void *cpu_addr, dma_addr_t dma_addr,
-                              size_t size, unsigned long attrs)
-{
-       unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
-       struct vm_struct *area = find_vm_area(cpu_addr);
-
-       if (!is_vmalloc_addr(cpu_addr)) {
-               struct page *page = virt_to_page(cpu_addr);
-               return __swiotlb_get_sgtable_page(sgt, page, size);
-       }
-
-       if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {
-               /*
-                * DMA_ATTR_FORCE_CONTIGUOUS allocations are always remapped,
-                *  hence in the vmalloc space.
-                */
-               struct page *page = vmalloc_to_page(cpu_addr);
-               return __swiotlb_get_sgtable_page(sgt, page, size);
-       }
-
-       if (WARN_ON(!area || !area->pages))
-               return -ENXIO;
-
-       return sg_alloc_table_from_pages(sgt, area->pages, count, 0, size,
-                                        GFP_KERNEL);
-}
-
-static void __iommu_sync_single_for_cpu(struct device *dev,
-                                       dma_addr_t dev_addr, size_t size,
-                                       enum dma_data_direction dir)
-{
-       phys_addr_t phys;
-
-       if (dev_is_dma_coherent(dev))
-               return;
-
-       phys = iommu_iova_to_phys(iommu_get_dma_domain(dev), dev_addr);
-       arch_sync_dma_for_cpu(dev, phys, size, dir);
-}
-
-static void __iommu_sync_single_for_device(struct device *dev,
-                                          dma_addr_t dev_addr, size_t size,
-                                          enum dma_data_direction dir)
-{
-       phys_addr_t phys;
-
-       if (dev_is_dma_coherent(dev))
-               return;
-
-       phys = iommu_iova_to_phys(iommu_get_dma_domain(dev), dev_addr);
-       arch_sync_dma_for_device(dev, phys, size, dir);
-}
-
-static dma_addr_t __iommu_map_page(struct device *dev, struct page *page,
-                                  unsigned long offset, size_t size,
-                                  enum dma_data_direction dir,
-                                  unsigned long attrs)
-{
-       bool coherent = dev_is_dma_coherent(dev);
-       int prot = dma_info_to_prot(dir, coherent, attrs);
-       dma_addr_t dev_addr = iommu_dma_map_page(dev, page, offset, size, prot);
-
-       if (!coherent && !(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
-           dev_addr != DMA_MAPPING_ERROR)
-               __dma_map_area(page_address(page) + offset, size, dir);
-
-       return dev_addr;
-}
-
-static void __iommu_unmap_page(struct device *dev, dma_addr_t dev_addr,
-                              size_t size, enum dma_data_direction dir,
-                              unsigned long attrs)
-{
-       if ((attrs & DMA_ATTR_SKIP_CPU_SYNC) == 0)
-               __iommu_sync_single_for_cpu(dev, dev_addr, size, dir);
-
-       iommu_dma_unmap_page(dev, dev_addr, size, dir, attrs);
-}
-
-static void __iommu_sync_sg_for_cpu(struct device *dev,
-                                   struct scatterlist *sgl, int nelems,
-                                   enum dma_data_direction dir)
-{
-       struct scatterlist *sg;
-       int i;
-
-       if (dev_is_dma_coherent(dev))
-               return;
-
-       for_each_sg(sgl, sg, nelems, i)
-               arch_sync_dma_for_cpu(dev, sg_phys(sg), sg->length, dir);
-}
-
-static void __iommu_sync_sg_for_device(struct device *dev,
-                                      struct scatterlist *sgl, int nelems,
-                                      enum dma_data_direction dir)
-{
-       struct scatterlist *sg;
-       int i;
-
-       if (dev_is_dma_coherent(dev))
-               return;
-
-       for_each_sg(sgl, sg, nelems, i)
-               arch_sync_dma_for_device(dev, sg_phys(sg), sg->length, dir);
-}
-
-static int __iommu_map_sg_attrs(struct device *dev, struct scatterlist *sgl,
-                               int nelems, enum dma_data_direction dir,
-                               unsigned long attrs)
-{
-       bool coherent = dev_is_dma_coherent(dev);
-
-       if ((attrs & DMA_ATTR_SKIP_CPU_SYNC) == 0)
-               __iommu_sync_sg_for_device(dev, sgl, nelems, dir);
-
-       return iommu_dma_map_sg(dev, sgl, nelems,
-                               dma_info_to_prot(dir, coherent, attrs));
-}
-
-static void __iommu_unmap_sg_attrs(struct device *dev,
-                                  struct scatterlist *sgl, int nelems,
-                                  enum dma_data_direction dir,
-                                  unsigned long attrs)
-{
-       if ((attrs & DMA_ATTR_SKIP_CPU_SYNC) == 0)
-               __iommu_sync_sg_for_cpu(dev, sgl, nelems, dir);
-
-       iommu_dma_unmap_sg(dev, sgl, nelems, dir, attrs);
-}
-
-static const struct dma_map_ops iommu_dma_ops = {
-       .alloc = __iommu_alloc_attrs,
-       .free = __iommu_free_attrs,
-       .mmap = __iommu_mmap_attrs,
-       .get_sgtable = __iommu_get_sgtable,
-       .map_page = __iommu_map_page,
-       .unmap_page = __iommu_unmap_page,
-       .map_sg = __iommu_map_sg_attrs,
-       .unmap_sg = __iommu_unmap_sg_attrs,
-       .sync_single_for_cpu = __iommu_sync_single_for_cpu,
-       .sync_single_for_device = __iommu_sync_single_for_device,
-       .sync_sg_for_cpu = __iommu_sync_sg_for_cpu,
-       .sync_sg_for_device = __iommu_sync_sg_for_device,
-       .map_resource = iommu_dma_map_resource,
-       .unmap_resource = iommu_dma_unmap_resource,
-};
-
-static int __init __iommu_dma_init(void)
-{
-       return iommu_dma_init();
-}
-arch_initcall(__iommu_dma_init);
-
-static void __iommu_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
-                                 const struct iommu_ops *ops)
-{
-       struct iommu_domain *domain;
-
-       if (!ops)
-               return;
-
-       /*
-        * The IOMMU core code allocates the default DMA domain, which the
-        * underlying IOMMU driver needs to support via the dma-iommu layer.
-        */
-       domain = iommu_get_domain_for_dev(dev);
-
-       if (!domain)
-               goto out_err;
-
-       if (domain->type == IOMMU_DOMAIN_DMA) {
-               if (iommu_dma_init_domain(domain, dma_base, size, dev))
-                       goto out_err;
-
-               dev->dma_ops = &iommu_dma_ops;
-       }
-
-       return;
-
-out_err:
-        pr_warn("Failed to set up IOMMU for device %s; retaining platform DMA 
ops\n",
-                dev_name(dev));
-}
-
 void arch_teardown_dma_ops(struct device *dev)
 {
        dev->dma_ops = NULL;
 }
-
-#else
-
-static void __iommu_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
-                                 const struct iommu_ops *iommu)
-{ }
-
-#endif  /* CONFIG_IOMMU_DMA */
+#endif
 
 void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
                        const struct iommu_ops *iommu, bool coherent)
 {
        dev->dma_coherent = coherent;
-       __iommu_setup_dma_ops(dev, dma_base, size, iommu);
+       if (iommu)
+               iommu_setup_dma_ops(dev, dma_base, size, iommu);
 
 #ifdef CONFIG_XEN
        if (xen_initial_domain())
diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index 6f07f3b21816..bdc14baf2ee5 100644
--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig
@@ -95,6 +95,7 @@ config IOMMU_DMA
        select IOMMU_API
        select IOMMU_IOVA
        select NEED_SG_DMA_LENGTH
+       depends on DMA_DIRECT_REMAP
 
 config FSL_PAMU
        bool "Freescale IOMMU support"
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index f915cb7c46e6..d14fe9f8c692 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -21,6 +21,7 @@
 
 #include <linux/acpi_iort.h>
 #include <linux/device.h>
+#include <linux/dma-contiguous.h>
 #include <linux/dma-iommu.h>
 #include <linux/dma-noncoherent.h>
 #include <linux/gfp.h>
@@ -79,11 +80,6 @@ static struct iommu_dma_cookie *cookie_alloc(enum 
iommu_dma_cookie_type type)
        return cookie;
 }
 
-int iommu_dma_init(void)
-{
-       return iova_cache_get();
-}
-
 /**
  * iommu_get_dma_cookie - Acquire DMA-API resources for a domain
  * @domain: IOMMU domain to prepare for DMA-API usage
@@ -285,7 +281,7 @@ static void iommu_dma_flush_iotlb_all(struct iova_domain 
*iovad)
  * to ensure it is an invalid IOVA. It is safe to reinitialise a domain, but
  * any change which could make prior IOVAs invalid will fail.
  */
-int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base,
+static int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base,
                u64 size, struct device *dev)
 {
        struct iommu_dma_cookie *cookie = domain->iova_cookie;
@@ -336,7 +332,6 @@ int iommu_dma_init_domain(struct iommu_domain *domain, 
dma_addr_t base,
 
        return iova_reserve_iommu_regions(dev, domain);
 }
-EXPORT_SYMBOL(iommu_dma_init_domain);
 
 /**
  * dma_info_to_prot - Translate DMA API directions and attributes to IOMMU API
@@ -347,7 +342,7 @@ EXPORT_SYMBOL(iommu_dma_init_domain);
  *
  * Return: corresponding IOMMU API page protection flags
  */
-int dma_info_to_prot(enum dma_data_direction dir, bool coherent,
+static int dma_info_to_prot(enum dma_data_direction dir, bool coherent,
                     unsigned long attrs)
 {
        int prot = coherent ? IOMMU_CACHE : 0;
@@ -506,17 +501,17 @@ static struct page **__iommu_dma_alloc_pages(struct 
device *dev,
 }
 
 /**
- * iommu_dma_free - Free a buffer allocated by iommu_dma_alloc()
+ * iommu_dma_free - Free a buffer allocated by __iommu_dma_alloc()
  * @dev: Device which owns this buffer
- * @pages: Array of buffer pages as returned by iommu_dma_alloc()
+ * @pages: Array of buffer pages as returned by __iommu_dma_alloc()
  * @size: Size of buffer in bytes
  * @handle: DMA address of buffer
  *
  * Frees both the pages associated with the buffer, and the array
  * describing them
  */
-void iommu_dma_free(struct device *dev, struct page **pages, size_t size,
-               dma_addr_t *handle)
+static void __iommu_dma_free(struct device *dev, struct page **pages,
+               size_t size, dma_addr_t *handle)
 {
        __iommu_dma_unmap(iommu_get_dma_domain(dev), *handle, size);
        __iommu_dma_free_pages(pages, PAGE_ALIGN(size) >> PAGE_SHIFT);
@@ -524,7 +519,7 @@ void iommu_dma_free(struct device *dev, struct page 
**pages, size_t size,
 }
 
 /**
- * iommu_dma_alloc - Allocate and map a buffer contiguous in IOVA space
+ * __iommu_dma_alloc - Allocate and map a buffer contiguous in IOVA space
  * @dev: Device to allocate memory for. Must be a real device
  *      attached to an iommu_dma_domain
  * @size: Size of buffer in bytes
@@ -539,8 +534,8 @@ void iommu_dma_free(struct device *dev, struct page 
**pages, size_t size,
  * Return: Array of struct page pointers describing the buffer,
  *        or NULL on failure.
  */
-struct page **iommu_dma_alloc(struct device *dev, size_t size, gfp_t gfp,
-               unsigned long attrs, int prot, dma_addr_t *handle)
+static struct page **__iommu_dma_alloc(struct device *dev, size_t size,
+               gfp_t gfp, unsigned long attrs, int prot, dma_addr_t *handle)
 {
        struct iommu_domain *domain = iommu_get_dma_domain(dev);
        struct iommu_dma_cookie *cookie = domain->iova_cookie;
@@ -602,16 +597,16 @@ struct page **iommu_dma_alloc(struct device *dev, size_t 
size, gfp_t gfp,
 }
 
 /**
- * iommu_dma_mmap - Map a buffer into provided user VMA
- * @pages: Array representing buffer from iommu_dma_alloc()
+ * __iommu_dma_mmap - Map a buffer into provided user VMA
+ * @pages: Array representing buffer from __iommu_dma_alloc()
  * @size: Size of buffer in bytes
  * @vma: VMA describing requested userspace mapping
  *
  * Maps the pages of the buffer in @pages into @vma. The caller is responsible
  * for verifying the correct size and protection of @vma beforehand.
  */
-
-int iommu_dma_mmap(struct page **pages, size_t size, struct vm_area_struct 
*vma)
+static int __iommu_dma_mmap(struct page **pages, size_t size,
+               struct vm_area_struct *vma)
 {
        unsigned long uaddr = vma->vm_start;
        unsigned int i, count = PAGE_ALIGN(size) >> PAGE_SHIFT;
@@ -626,6 +621,58 @@ int iommu_dma_mmap(struct page **pages, size_t size, 
struct vm_area_struct *vma)
        return ret;
 }
 
+static void iommu_dma_sync_single_for_cpu(struct device *dev,
+               dma_addr_t dma_handle, size_t size, enum dma_data_direction dir)
+{
+       phys_addr_t phys;
+
+       if (dev_is_dma_coherent(dev))
+               return;
+
+       phys = iommu_iova_to_phys(iommu_get_dma_domain(dev), dma_handle);
+       arch_sync_dma_for_cpu(dev, phys, size, dir);
+}
+
+static void iommu_dma_sync_single_for_device(struct device *dev,
+               dma_addr_t dma_handle, size_t size, enum dma_data_direction dir)
+{
+       phys_addr_t phys;
+
+       if (dev_is_dma_coherent(dev))
+               return;
+
+       phys = iommu_iova_to_phys(iommu_get_dma_domain(dev), dma_handle);
+       arch_sync_dma_for_device(dev, phys, size, dir);
+}
+
+static void iommu_dma_sync_sg_for_cpu(struct device *dev,
+               struct scatterlist *sgl, int nelems,
+               enum dma_data_direction dir)
+{
+       struct scatterlist *sg;
+       int i;
+
+       if (dev_is_dma_coherent(dev))
+               return;
+
+       for_each_sg(sgl, sg, nelems, i)
+               arch_sync_dma_for_cpu(dev, sg_phys(sg), sg->length, dir);
+}
+
+static void iommu_dma_sync_sg_for_device(struct device *dev,
+               struct scatterlist *sgl, int nelems,
+               enum dma_data_direction dir)
+{
+       struct scatterlist *sg;
+       int i;
+
+       if (dev_is_dma_coherent(dev))
+               return;
+
+       for_each_sg(sgl, sg, nelems, i)
+               arch_sync_dma_for_device(dev, sg_phys(sg), sg->length, dir);
+}
+
 static dma_addr_t __iommu_dma_map(struct device *dev, phys_addr_t phys,
                size_t size, int prot, struct iommu_domain *domain)
 {
@@ -649,19 +696,44 @@ static dma_addr_t __iommu_dma_map(struct device *dev, 
phys_addr_t phys,
        return iova + iova_off;
 }
 
-dma_addr_t iommu_dma_map_page(struct device *dev, struct page *page,
+static dma_addr_t __iommu_dma_map_page(struct device *dev, struct page *page,
                unsigned long offset, size_t size, int prot)
 {
        return __iommu_dma_map(dev, page_to_phys(page) + offset, size, prot,
                        iommu_get_dma_domain(dev));
 }
 
-void iommu_dma_unmap_page(struct device *dev, dma_addr_t handle, size_t size,
-               enum dma_data_direction dir, unsigned long attrs)
+static void __iommu_dma_unmap_page(struct device *dev, dma_addr_t handle,
+               size_t size, enum dma_data_direction dir, unsigned long attrs)
 {
        __iommu_dma_unmap(iommu_get_dma_domain(dev), handle, size);
 }
 
+static dma_addr_t iommu_dma_map_page(struct device *dev, struct page *page,
+               unsigned long offset, size_t size, enum dma_data_direction dir,
+               unsigned long attrs)
+{
+       phys_addr_t phys = page_to_phys(page) + offset;
+       bool coherent = dev_is_dma_coherent(dev);
+       dma_addr_t dma_handle;
+
+       dma_handle =__iommu_dma_map(dev, phys, size,
+                       dma_info_to_prot(dir, coherent, attrs),
+                       iommu_get_dma_domain(dev));
+       if (!coherent && !(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
+           dma_handle != DMA_MAPPING_ERROR)
+               arch_sync_dma_for_device(dev, phys, size, dir);
+       return dma_handle;
+}
+
+static void iommu_dma_unmap_page(struct device *dev, dma_addr_t dma_handle,
+               size_t size, enum dma_data_direction dir, unsigned long attrs)
+{
+       if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+               iommu_dma_sync_single_for_cpu(dev, dma_handle, size, dir);
+       __iommu_dma_unmap(iommu_get_domain_for_dev(dev), dma_handle, size);
+}
+
 /*
  * Prepare a successfully-mapped scatterlist to give back to the caller.
  *
@@ -744,18 +816,22 @@ static void __invalidate_sg(struct scatterlist *sg, int 
nents)
  * impedance-matching, to be able to hand off a suitably-aligned list,
  * but still preserve the original offsets and sizes for the caller.
  */
-int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg,
-               int nents, int prot)
+static int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg,
+               int nents, enum dma_data_direction dir, unsigned long attrs)
 {
        struct iommu_domain *domain = iommu_get_dma_domain(dev);
        struct iommu_dma_cookie *cookie = domain->iova_cookie;
        struct iova_domain *iovad = &cookie->iovad;
        struct scatterlist *s, *prev = NULL;
+       int prot = dma_info_to_prot(dir, dev_is_dma_coherent(dev), attrs);
        dma_addr_t iova;
        size_t iova_len = 0;
        unsigned long mask = dma_get_seg_boundary(dev);
        int i;
 
+       if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+               iommu_dma_sync_sg_for_device(dev, sg, nents, dir);
+
        /*
         * Work out how much IOVA space we need, and align the segments to
         * IOVA granules for the IOMMU driver to handle. With some clever
@@ -815,12 +891,16 @@ int iommu_dma_map_sg(struct device *dev, struct 
scatterlist *sg,
        return 0;
 }
 
-void iommu_dma_unmap_sg(struct device *dev, struct scatterlist *sg, int nents,
-               enum dma_data_direction dir, unsigned long attrs)
+static void iommu_dma_unmap_sg(struct device *dev, struct scatterlist *sg,
+               int nents, enum dma_data_direction dir, unsigned long attrs)
 {
        dma_addr_t start, end;
        struct scatterlist *tmp;
        int i;
+
+       if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) == 0)
+               iommu_dma_sync_sg_for_cpu(dev, sg, nents, dir);
+
        /*
         * The scatterlist segments are mapped into a single
         * contiguous IOVA allocation, so this is incredibly easy.
@@ -835,7 +915,7 @@ void iommu_dma_unmap_sg(struct device *dev, struct 
scatterlist *sg, int nents,
        __iommu_dma_unmap(iommu_get_dma_domain(dev), start, end - start);
 }
 
-dma_addr_t iommu_dma_map_resource(struct device *dev, phys_addr_t phys,
+static dma_addr_t iommu_dma_map_resource(struct device *dev, phys_addr_t phys,
                size_t size, enum dma_data_direction dir, unsigned long attrs)
 {
        return __iommu_dma_map(dev, phys, size,
@@ -843,12 +923,257 @@ dma_addr_t iommu_dma_map_resource(struct device *dev, 
phys_addr_t phys,
                        iommu_get_dma_domain(dev));
 }
 
-void iommu_dma_unmap_resource(struct device *dev, dma_addr_t handle,
+static void iommu_dma_unmap_resource(struct device *dev, dma_addr_t handle,
                size_t size, enum dma_data_direction dir, unsigned long attrs)
 {
        __iommu_dma_unmap(iommu_get_dma_domain(dev), handle, size);
 }
 
+static void *iommu_dma_alloc(struct device *dev, size_t size,
+               dma_addr_t *handle, gfp_t gfp, unsigned long attrs)
+{
+       bool coherent = dev_is_dma_coherent(dev);
+       int ioprot = dma_info_to_prot(DMA_BIDIRECTIONAL, coherent, attrs);
+       size_t iosize = size;
+       void *addr;
+
+       size = PAGE_ALIGN(size);
+
+       /*
+        * Some drivers rely on this, and we probably don't want the
+        * possibility of stale kernel data being read by devices anyway.
+        */
+       gfp |= __GFP_ZERO;
+
+       if (!gfpflags_allow_blocking(gfp)) {
+               struct page *page;
+               /*
+                * In atomic context we can't remap anything, so we'll only
+                * get the virtually contiguous buffer we need by way of a
+                * physically contiguous allocation.
+                */
+               if (coherent) {
+                       page = alloc_pages(gfp, get_order(size));
+                       addr = page ? page_address(page) : NULL;
+               } else {
+                       addr = dma_alloc_from_pool(size, &page, gfp);
+               }
+               if (!addr)
+                       return NULL;
+
+               *handle = __iommu_dma_map_page(dev, page, 0, iosize, ioprot);
+               if (*handle == DMA_MAPPING_ERROR) {
+                       if (coherent)
+                               __free_pages(page, get_order(size));
+                       else
+                               dma_free_from_pool(addr, size);
+                       addr = NULL;
+               }
+       } else if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {
+               pgprot_t prot = arch_dma_mmap_pgprot(dev, PAGE_KERNEL, attrs);
+               struct page *page;
+
+               page = dma_alloc_from_contiguous(dev, size >> PAGE_SHIFT,
+                                       get_order(size), gfp & __GFP_NOWARN);
+               if (!page)
+                       return NULL;
+
+               *handle = __iommu_dma_map_page(dev, page, 0, iosize, ioprot);
+               if (*handle == DMA_MAPPING_ERROR) {
+                       dma_release_from_contiguous(dev, page,
+                                                   size >> PAGE_SHIFT);
+                       return NULL;
+               }
+               addr = dma_common_contiguous_remap(page, size, VM_USERMAP,
+                                                  prot,
+                                                  __builtin_return_address(0));
+               if (addr) {
+                       if (!coherent)
+                               arch_dma_prep_coherent(page, iosize);
+                       memset(addr, 0, size);
+               } else {
+                       __iommu_dma_unmap_page(dev, *handle, iosize, 0, attrs);
+                       dma_release_from_contiguous(dev, page,
+                                                   size >> PAGE_SHIFT);
+               }
+       } else {
+               pgprot_t prot = arch_dma_mmap_pgprot(dev, PAGE_KERNEL, attrs);
+               struct page **pages;
+
+               pages = __iommu_dma_alloc(dev, iosize, gfp, attrs, ioprot,
+                                       handle);
+               if (!pages)
+                       return NULL;
+
+               addr = dma_common_pages_remap(pages, size, VM_USERMAP, prot,
+                                             __builtin_return_address(0));
+               if (!addr)
+                       __iommu_dma_free(dev, pages, iosize, handle);
+       }
+       return addr;
+}
+
+static void iommu_dma_free(struct device *dev, size_t size, void *cpu_addr,
+               dma_addr_t handle, unsigned long attrs)
+{
+       size_t iosize = size;
+
+       size = PAGE_ALIGN(size);
+       /*
+        * @cpu_addr will be one of 4 things depending on how it was allocated:
+        * - A remapped array of pages for contiguous allocations.
+        * - A remapped array of pages from __iommu_dma_alloc(), for all
+        *   non-atomic allocations.
+        * - A non-cacheable alias from the atomic pool, for atomic
+        *   allocations by non-coherent devices.
+        * - A normal lowmem address, for atomic allocations by
+        *   coherent devices.
+        * Hence how dodgy the below logic looks...
+        */
+       if (dma_in_atomic_pool(cpu_addr, size)) {
+               __iommu_dma_unmap_page(dev, handle, iosize, 0, 0);
+               dma_free_from_pool(cpu_addr, size);
+       } else if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {
+               struct page *page = vmalloc_to_page(cpu_addr);
+
+               __iommu_dma_unmap_page(dev, handle, iosize, 0, attrs);
+               dma_release_from_contiguous(dev, page, size >> PAGE_SHIFT);
+               dma_common_free_remap(cpu_addr, size, VM_USERMAP);
+       } else if (is_vmalloc_addr(cpu_addr)){
+               struct vm_struct *area = find_vm_area(cpu_addr);
+
+               if (WARN_ON(!area || !area->pages))
+                       return;
+               __iommu_dma_free(dev, area->pages, iosize, &handle);
+               dma_common_free_remap(cpu_addr, size, VM_USERMAP);
+       } else {
+               __iommu_dma_unmap_page(dev, handle, iosize, 0, 0);
+               __free_pages(virt_to_page(cpu_addr), get_order(size));
+       }
+}
+
+static int __iommu_dma_mmap_pfn(struct vm_area_struct *vma,
+                             unsigned long pfn, size_t size)
+{
+       return remap_pfn_range(vma, vma->vm_start, pfn + vma->vm_pgoff,
+                              vma->vm_end - vma->vm_start,
+                              vma->vm_page_prot);
+}
+
+static int iommu_dma_mmap(struct device *dev, struct vm_area_struct *vma,
+               void *cpu_addr, dma_addr_t dma_addr, size_t size,
+               unsigned long attrs)
+{
+       unsigned long nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
+       unsigned long off = vma->vm_pgoff;
+       struct vm_struct *area;
+       int ret;
+
+       vma->vm_page_prot = arch_dma_mmap_pgprot(dev, vma->vm_page_prot, attrs);
+
+       if (dma_mmap_from_dev_coherent(dev, vma, cpu_addr, size, &ret))
+               return ret;
+
+       if (off >= nr_pages || vma_pages(vma) > nr_pages - off)
+               return -ENXIO;
+
+       if (!is_vmalloc_addr(cpu_addr)) {
+               unsigned long pfn = page_to_pfn(virt_to_page(cpu_addr));
+               return __iommu_dma_mmap_pfn(vma, pfn, size);
+       }
+
+       if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {
+               /*
+                * DMA_ATTR_FORCE_CONTIGUOUS allocations are always remapped,
+                * hence in the vmalloc space.
+                */
+               unsigned long pfn = vmalloc_to_pfn(cpu_addr);
+               return __iommu_dma_mmap_pfn(vma, pfn, size);
+       }
+
+       area = find_vm_area(cpu_addr);
+       if (WARN_ON(!area || !area->pages))
+               return -ENXIO;
+
+       return __iommu_dma_mmap(area->pages, size, vma);
+}
+
+static int __iommu_dma_get_sgtable_page(struct sg_table *sgt, struct page 
*page,
+               size_t size)
+{
+       int ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
+
+       if (!ret)
+               sg_set_page(sgt->sgl, page, PAGE_ALIGN(size), 0);
+       return ret;
+}
+
+static int iommu_dma_get_sgtable(struct device *dev, struct sg_table *sgt,
+               void *cpu_addr, dma_addr_t dma_addr, size_t size,
+               unsigned long attrs)
+{
+       unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
+       struct vm_struct *area = find_vm_area(cpu_addr);
+
+       if (!is_vmalloc_addr(cpu_addr)) {
+               struct page *page = virt_to_page(cpu_addr);
+               return __iommu_dma_get_sgtable_page(sgt, page, size);
+       }
+
+       if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {
+               /*
+                * DMA_ATTR_FORCE_CONTIGUOUS allocations are always remapped,
+                * hence in the vmalloc space.
+                */
+               struct page *page = vmalloc_to_page(cpu_addr);
+               return __iommu_dma_get_sgtable_page(sgt, page, size);
+       }
+
+       if (WARN_ON(!area || !area->pages))
+               return -ENXIO;
+
+       return sg_alloc_table_from_pages(sgt, area->pages, count, 0, size,
+                                        GFP_KERNEL);
+}
+
+static const struct dma_map_ops iommu_dma_ops = {
+       .alloc                  = iommu_dma_alloc,
+       .free                   = iommu_dma_free,
+       .mmap                   = iommu_dma_mmap,
+       .get_sgtable            = iommu_dma_get_sgtable,
+       .map_page               = iommu_dma_map_page,
+       .unmap_page             = iommu_dma_unmap_page,
+       .map_sg                 = iommu_dma_map_sg,
+       .unmap_sg               = iommu_dma_unmap_sg,
+       .sync_single_for_cpu    = iommu_dma_sync_single_for_cpu,
+       .sync_single_for_device = iommu_dma_sync_single_for_device,
+       .sync_sg_for_cpu        = iommu_dma_sync_sg_for_cpu,
+       .sync_sg_for_device     = iommu_dma_sync_sg_for_device,
+       .map_resource           = iommu_dma_map_resource,
+       .unmap_resource         = iommu_dma_unmap_resource,
+};
+
+/*
+ * The IOMMU core code allocates the default DMA domain, which the underlying
+ * IOMMU driver needs to support via the dma-iommu layer.
+ */
+void iommu_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
+               const struct iommu_ops *ops)
+{
+       struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
+
+       if (!domain || domain->type != IOMMU_DOMAIN_DMA)
+               goto out_err;
+       if (iommu_dma_init_domain(domain, dma_base, size, dev))
+               goto out_err;
+
+       dev->dma_ops = &iommu_dma_ops;
+       return;
+out_err:
+        pr_warn("Failed to set up IOMMU for device %s; retaining platform DMA 
ops\n",
+                dev_name(dev));
+}
+
 static struct iommu_dma_msi_page *iommu_dma_get_msi_page(struct device *dev,
                phys_addr_t msi_addr, struct iommu_domain *domain)
 {
@@ -921,3 +1246,5 @@ void iommu_dma_map_msi_msg(int irq, struct msi_msg *msg)
                msg->address_lo += lower_32_bits(msi_page->iova);
        }
 }
+
+arch_initcall(iova_cache_get);
diff --git a/include/linux/dma-iommu.h b/include/linux/dma-iommu.h
index 10ef708a605c..1d1a3b58d574 100644
--- a/include/linux/dma-iommu.h
+++ b/include/linux/dma-iommu.h
@@ -25,49 +25,14 @@
 #include <linux/msi.h>
 #include <linux/types.h>
 
-int iommu_dma_init(void);
-
 /* Domain management interface for IOMMU drivers */
 int iommu_get_dma_cookie(struct iommu_domain *domain);
 int iommu_get_msi_cookie(struct iommu_domain *domain, dma_addr_t base);
 void iommu_put_dma_cookie(struct iommu_domain *domain);
 
 /* Setup call for arch DMA mapping code */
-int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base,
-               u64 size, struct device *dev);
-
-/* General helpers for DMA-API <-> IOMMU-API interaction */
-int dma_info_to_prot(enum dma_data_direction dir, bool coherent,
-                    unsigned long attrs);
-
-/*
- * These implement the bulk of the relevant DMA mapping callbacks, but require
- * the arch code to take care of attributes and cache maintenance
- */
-struct page **iommu_dma_alloc(struct device *dev, size_t size, gfp_t gfp,
-               unsigned long attrs, int prot, dma_addr_t *handle);
-void iommu_dma_free(struct device *dev, struct page **pages, size_t size,
-               dma_addr_t *handle);
-
-int iommu_dma_mmap(struct page **pages, size_t size, struct vm_area_struct 
*vma);
-
-dma_addr_t iommu_dma_map_page(struct device *dev, struct page *page,
-               unsigned long offset, size_t size, int prot);
-int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg,
-               int nents, int prot);
-
-/*
- * Arch code with no special attribute handling may use these
- * directly as DMA mapping callbacks for simplicity
- */
-void iommu_dma_unmap_page(struct device *dev, dma_addr_t handle, size_t size,
-               enum dma_data_direction dir, unsigned long attrs);
-void iommu_dma_unmap_sg(struct device *dev, struct scatterlist *sg, int nents,
-               enum dma_data_direction dir, unsigned long attrs);
-dma_addr_t iommu_dma_map_resource(struct device *dev, phys_addr_t phys,
-               size_t size, enum dma_data_direction dir, unsigned long attrs);
-void iommu_dma_unmap_resource(struct device *dev, dma_addr_t handle,
-               size_t size, enum dma_data_direction dir, unsigned long attrs);
+void iommu_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
+               const struct iommu_ops *ops);
 
 /* The DMA API isn't _quite_ the whole story, though... */
 void iommu_dma_map_msi_msg(int irq, struct msi_msg *msg);
@@ -76,12 +41,13 @@ void iommu_dma_get_resv_regions(struct device *dev, struct 
list_head *list);
 #else /* CONFIG_IOMMU_DMA */
 
 struct iommu_domain;
+struct iommu_ops;
 struct msi_msg;
 struct device;
 
-static inline int iommu_dma_init(void)
+static inline void iommu_setup_dma_ops(struct device *dev, u64 dma_base,
+               u64 size, const struct iommu_ops *ops)
 {
-       return 0;
 }
 
 static inline int iommu_get_dma_cookie(struct iommu_domain *domain)
-- 
2.20.1

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