[RFC PATCH 4/5] arm64: add IOMMU dma_ops
Robin Murphy
robin.murphy at arm.com
Mon Jan 12 12:48:56 PST 2015
Taking some inspiration from the arch/arm code, implement the
arch-specific side of the DMA mapping ops using the new IOMMU-DMA layer.
Signed-off-by: Robin Murphy <robin.murphy at arm.com>
---
arch/arm64/include/asm/device.h | 3 +
arch/arm64/include/asm/dma-mapping.h | 12 ++
arch/arm64/mm/dma-mapping.c | 297 +++++++++++++++++++++++++++++++++++
3 files changed, 312 insertions(+)
diff --git a/arch/arm64/include/asm/device.h b/arch/arm64/include/asm/device.h
index 243ef25..c17f100 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_mapping *mapping;
+#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..82082c4 100644
--- a/arch/arm64/include/asm/dma-mapping.h
+++ b/arch/arm64/include/asm/dma-mapping.h
@@ -64,11 +64,23 @@ static inline bool is_device_dma_coherent(struct device *dev)
static inline dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
{
+#ifdef CONFIG_IOMMU_DMA
+ /* We don't have an easy way of dealing with this... */
+ BUG_ON(dev->archdata.mapping);
+#endif
return (dma_addr_t)paddr;
}
+#ifdef CONFIG_IOMMU_DMA
+phys_addr_t iova_to_phys(struct device *dev, dma_addr_t dev_addr);
+#endif
+
static inline phys_addr_t dma_to_phys(struct device *dev, dma_addr_t dev_addr)
{
+#ifdef CONFIG_IOMMU_DMA
+ if (dev->archdata.mapping)
+ return iova_to_phys(dev, dev_addr);
+#endif
return (phys_addr_t)dev_addr;
}
diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
index 0a24b9b..8e449a7 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 +427,9 @@ static int __init arm64_dma_init(void)
ret |= swiotlb_late_init();
ret |= atomic_pool_init();
+#ifdef CONFIG_IOMMU_DMA
+ ret |= iommu_dma_init();
+#endif
return ret;
}
@@ -439,3 +443,296 @@ 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);
+}
+
+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);
+ /*
+ * 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);
+
+ pages = iommu_dma_alloc_buffer(dev, size, gfp, attrs,
+ __dma_clear_buffer);
+ if (!pages)
+ return NULL;
+
+ *handle = iommu_dma_create_iova_mapping(dev, pages, size, coherent);
+ if (*handle == DMA_ERROR_CODE)
+ goto err_mapping;
+
+ addr = dma_common_pages_remap(pages, size, VM_USERMAP,
+ __get_dma_pgprot(attrs, prot, coherent),
+ __builtin_return_address(0));
+ if (addr)
+ return addr;
+
+ iommu_dma_release_iova_mapping(dev, *handle, size);
+err_mapping:
+ iommu_dma_free_buffer(dev, pages, size, attrs);
+ return NULL;
+}
+
+static void __iommu_free_attrs(struct device *dev, size_t size, void *cpu_addr,
+ dma_addr_t handle, struct dma_attrs *attrs)
+{
+ struct page **pages;
+
+ size = PAGE_ALIGN(size);
+ if (__in_atomic_pool(cpu_addr, size)) {
+ __iommu_free_atomic(dev, cpu_addr, handle, size);
+ return;
+ }
+
+ pages = __iommu_get_pages(cpu_addr, attrs);
+ if (!pages) {
+ WARN(1, "trying to free invalid coherent area: %p\n", cpu_addr);
+ return;
+ }
+
+ dma_common_free_remap(cpu_addr, size, VM_USERMAP);
+
+ iommu_dma_release_iova_mapping(dev, handle, size);
+ iommu_dma_free_buffer(dev, pages, size, attrs);
+}
+
+static inline void *iova_to_virt(struct device *dev, dma_addr_t dev_addr)
+{
+ if (dev_addr == DMA_ERROR_CODE)
+ return NULL;
+ return phys_to_virt(iova_to_phys(dev, dev_addr));
+}
+
+static void __iommu_sync_single_for_cpu(struct device *dev,
+ dma_addr_t dev_addr, size_t size,
+ enum dma_data_direction dir)
+{
+ if (!is_device_dma_coherent(dev))
+ __dma_unmap_area(iova_to_virt(dev, dev_addr), 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)
+{
+ if (!is_device_dma_coherent(dev))
+ __dma_map_area(iova_to_virt(dev, dev_addr), 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,
+ struct dma_attrs *attrs)
+{
+ dma_addr_t dev_addr;
+
+ if (is_device_dma_coherent(dev))
+ return iommu_dma_coherent_map_page(dev, page, offset, size,
+ dir, attrs);
+
+ dev_addr = iommu_dma_map_page(dev, page, offset, size, dir, attrs);
+ if (!dma_get_attr(DMA_ATTR_SKIP_CPU_SYNC, attrs))
+ __iommu_sync_single_for_device(dev, dev_addr, 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,
+ struct dma_attrs *attrs)
+{
+ if (!dma_get_attr(DMA_ATTR_SKIP_CPU_SYNC, attrs))
+ __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 (is_device_dma_coherent(dev))
+ return;
+
+ for_each_sg(sgl, sg, nelems, i) {
+ unsigned int len = sg_dma_len(sg);
+ void *virt = iova_to_virt(dev, sg_dma_address(sg));
+
+ if (virt && len)
+ __dma_unmap_area(virt, len, 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 (is_device_dma_coherent(dev))
+ return;
+
+ for_each_sg(sgl, sg, nelems, i) {
+ unsigned int len = sg_dma_len(sg);
+ void *virt = iova_to_virt(dev, sg_dma_address(sg));
+
+ if (virt && len)
+ __dma_map_area(virt, len, dir);
+ }
+}
+
+static int __iommu_map_sg_attrs(struct device *dev, struct scatterlist *sgl,
+ int nelems, enum dma_data_direction dir,
+ struct dma_attrs *attrs)
+{
+ int count;
+
+ if (is_device_dma_coherent(dev))
+ return iommu_dma_coherent_map_sg(dev, sgl, nelems, dir, attrs);
+
+ count = iommu_dma_map_sg(dev, sgl, nelems, dir, attrs);
+ if (!dma_get_attr(DMA_ATTR_SKIP_CPU_SYNC, attrs))
+ __iommu_sync_sg_for_device(dev, sgl, count, dir);
+
+ return count;
+}
+
+static void __iommu_unmap_sg_attrs(struct device *dev,
+ struct scatterlist *sgl, int nelems,
+ enum dma_data_direction dir,
+ struct dma_attrs *attrs)
+{
+ if (!dma_get_attr(DMA_ATTR_SKIP_CPU_SYNC, attrs))
+ __iommu_sync_sg_for_cpu(dev, sgl, nelems, dir);
+
+ iommu_dma_unmap_sg(dev, sgl, nelems, dir, attrs);
+}
+
+static struct dma_map_ops iommu_dma_ops = {
+ .alloc = __iommu_alloc_attrs,
+ .free = __iommu_free_attrs,
+ .mmap = __swiotlb_mmap,
+ .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,
+ .dma_supported = iommu_dma_supported,
+ .mapping_error = iommu_dma_mapping_error,
+};
+
+static void __iommu_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
+ struct iommu_ops *ops)
+{
+ struct iommu_dma_mapping *mapping;
+
+ if (!ops)
+ return;
+
+ mapping = iommu_dma_create_mapping(ops, dma_base, size);
+ if (!mapping) {
+ pr_warn("Failed to create %llu-byte IOMMU mapping for device %s\n",
+ size, dev_name(dev));
+ return;
+ }
+
+ if (iommu_dma_attach_device(dev, mapping))
+ pr_warn("Failed to attach device %s to IOMMU mapping\n",
+ dev_name(dev));
+ else
+ dev->archdata.dma_ops = &iommu_dma_ops;
+
+ /* drop the initial mapping refcount */
+ iommu_dma_release_mapping(mapping);
+}
+
+#else
+
+static void __iommu_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
+ struct iommu_ops *iommu)
+{ }
+
+#endif /* CONFIG_IOMMU_DMA */
--
1.9.1
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