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Subject[PATCH 10/10] arm64: use the generic swiotlb_dma_ops
Date
Now that the generic swiotlb code supports non-coherent DMA we can switch
to it for arm64. For that we need to refactor the existing
alloc/free/mmap/pgprot helpers to be used as the architecture hooks,
and implement the standard arch_sync_dma_for_{device,cpu} hooks for
cache maintaincance in the streaming dma hooks, which also implies
using the generic dma_coherent flag in struct device.

Note that we need to keep the old is_device_dma_coherent function around
for now, so that the shared arm/arm64 Xen code keeps working.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
arch/arm64/Kconfig | 4 +
arch/arm64/include/asm/device.h | 1 -
arch/arm64/include/asm/dma-mapping.h | 7 +-
arch/arm64/mm/dma-mapping.c | 257 +++++----------------------
4 files changed, 56 insertions(+), 213 deletions(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 1b1a0e95c751..c4db5131d837 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -11,6 +11,8 @@ config ARM64
select ARCH_CLOCKSOURCE_DATA
select ARCH_HAS_DEBUG_VIRTUAL
select ARCH_HAS_DEVMEM_IS_ALLOWED
+ select ARCH_HAS_DMA_COHERENT_TO_PFN
+ select ARCH_HAS_DMA_MMAP_PGPROT
select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
select ARCH_HAS_ELF_RANDOMIZE
select ARCH_HAS_FAST_MULTIPLIER
@@ -24,6 +26,8 @@ config ARM64
select ARCH_HAS_SG_CHAIN
select ARCH_HAS_STRICT_KERNEL_RWX
select ARCH_HAS_STRICT_MODULE_RWX
+ select ARCH_HAS_SYNC_DMA_FOR_DEVICE
+ select ARCH_HAS_SYNC_DMA_FOR_CPU
select ARCH_HAS_SYSCALL_WRAPPER
select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
select ARCH_HAVE_NMI_SAFE_CMPXCHG
diff --git a/arch/arm64/include/asm/device.h b/arch/arm64/include/asm/device.h
index 5a5fa47a6b18..3dd3d664c5c5 100644
--- a/arch/arm64/include/asm/device.h
+++ b/arch/arm64/include/asm/device.h
@@ -23,7 +23,6 @@ struct dev_archdata {
#ifdef CONFIG_XEN
const struct dma_map_ops *dev_dma_ops;
#endif
- bool dma_coherent;
};

struct pdev_archdata {
diff --git a/arch/arm64/include/asm/dma-mapping.h b/arch/arm64/include/asm/dma-mapping.h
index b7847eb8a7bb..c41f3fb1446c 100644
--- a/arch/arm64/include/asm/dma-mapping.h
+++ b/arch/arm64/include/asm/dma-mapping.h
@@ -44,10 +44,13 @@ void arch_teardown_dma_ops(struct device *dev);
#define arch_teardown_dma_ops arch_teardown_dma_ops
#endif

-/* do not use this function in a driver */
+/*
+ * Do not use this function in a driver, it is only provided for
+ * arch/arm/mm/xen.c, which is used by arm64 as well.
+ */
static inline bool is_device_dma_coherent(struct device *dev)
{
- return dev->archdata.dma_coherent;
+ return dev->dma_coherent;
}

#endif /* __KERNEL__ */
diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
index eee6cfcfde9e..3c75d69b54e7 100644
--- a/arch/arm64/mm/dma-mapping.c
+++ b/arch/arm64/mm/dma-mapping.c
@@ -25,6 +25,7 @@
#include <linux/slab.h>
#include <linux/genalloc.h>
#include <linux/dma-direct.h>
+#include <linux/dma-noncoherent.h>
#include <linux/dma-contiguous.h>
#include <linux/vmalloc.h>
#include <linux/swiotlb.h>
@@ -32,16 +33,6 @@

#include <asm/cacheflush.h>

-static int swiotlb __ro_after_init;
-
-static pgprot_t __get_dma_pgprot(unsigned long attrs, pgprot_t prot,
- bool coherent)
-{
- if (!coherent || (attrs & DMA_ATTR_WRITE_COMBINE))
- return pgprot_writecombine(prot);
- return prot;
-}
-
static struct gen_pool *atomic_pool __ro_after_init;

#define DEFAULT_DMA_COHERENT_POOL_SIZE SZ_256K
@@ -91,18 +82,16 @@ static int __free_from_pool(void *start, size_t size)
return 1;
}

-static void *__dma_alloc(struct device *dev, size_t size,
- dma_addr_t *dma_handle, gfp_t flags,
- unsigned long attrs)
+void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
+ gfp_t flags, unsigned long attrs)
{
struct page *page;
void *ptr, *coherent_ptr;
- bool coherent = is_device_dma_coherent(dev);
- pgprot_t prot = __get_dma_pgprot(attrs, PAGE_KERNEL, false);
+ pgprot_t prot = pgprot_writecombine(PAGE_KERNEL);

size = PAGE_ALIGN(size);

- if (!coherent && !gfpflags_allow_blocking(flags)) {
+ if (!gfpflags_allow_blocking(flags)) {
struct page *page = NULL;
void *addr = __alloc_from_pool(size, &page, flags);

@@ -116,10 +105,6 @@ static void *__dma_alloc(struct device *dev, size_t size,
if (!ptr)
goto no_mem;

- /* no need for non-cacheable mapping if coherent */
- if (coherent)
- return ptr;
-
/* remove any dirty cache lines on the kernel alias */
__dma_flush_area(ptr, size);

@@ -138,125 +123,50 @@ static void *__dma_alloc(struct device *dev, size_t size,
return NULL;
}

-static void __dma_free(struct device *dev, size_t size,
- void *vaddr, dma_addr_t dma_handle,
- unsigned long attrs)
-{
- void *swiotlb_addr = phys_to_virt(dma_to_phys(dev, dma_handle));
-
- size = PAGE_ALIGN(size);
-
- if (!is_device_dma_coherent(dev)) {
- if (__free_from_pool(vaddr, size))
- return;
- vunmap(vaddr);
- }
- dma_direct_free_pages(dev, size, swiotlb_addr, dma_handle, attrs);
-}
-
-static dma_addr_t __swiotlb_map_page(struct device *dev, struct page *page,
- unsigned long offset, size_t size,
- enum dma_data_direction dir,
- unsigned long attrs)
-{
- dma_addr_t dev_addr;
-
- dev_addr = swiotlb_map_page(dev, page, offset, size, dir, attrs);
- if (!is_device_dma_coherent(dev) &&
- (attrs & DMA_ATTR_SKIP_CPU_SYNC) == 0)
- __dma_map_area(phys_to_virt(dma_to_phys(dev, dev_addr)), size, dir);
-
- return dev_addr;
-}
-
-
-static void __swiotlb_unmap_page(struct device *dev, dma_addr_t dev_addr,
- size_t size, enum dma_data_direction dir,
- unsigned long attrs)
+void arch_dma_free(struct device *dev, size_t size, void *vaddr,
+ dma_addr_t dma_handle, unsigned long attrs)
{
- if (!is_device_dma_coherent(dev) &&
- (attrs & DMA_ATTR_SKIP_CPU_SYNC) == 0)
- __dma_unmap_area(phys_to_virt(dma_to_phys(dev, dev_addr)), size, dir);
- swiotlb_unmap_page(dev, dev_addr, size, dir, attrs);
+ if (__free_from_pool(vaddr, PAGE_ALIGN(size)))
+ return;
+ vunmap(vaddr);
+ dma_direct_free_pages(dev, size, vaddr, dma_handle, attrs);
}

-static int __swiotlb_map_sg_attrs(struct device *dev, struct scatterlist *sgl,
- int nelems, enum dma_data_direction dir,
- unsigned long attrs)
+long arch_dma_coherent_to_pfn(struct device *dev, void *cpu_addr,
+ dma_addr_t dma_addr)
{
- struct scatterlist *sg;
- int i, ret;
-
- ret = swiotlb_map_sg_attrs(dev, sgl, nelems, dir, attrs);
- if (!is_device_dma_coherent(dev) &&
- (attrs & DMA_ATTR_SKIP_CPU_SYNC) == 0)
- for_each_sg(sgl, sg, ret, i)
- __dma_map_area(phys_to_virt(dma_to_phys(dev, sg->dma_address)),
- sg->length, dir);
-
- return ret;
+ return __phys_to_pfn(dma_to_phys(dev, dma_addr));
}

-static void __swiotlb_unmap_sg_attrs(struct device *dev,
- struct scatterlist *sgl, int nelems,
- enum dma_data_direction dir,
- unsigned long attrs)
+pgprot_t arch_dma_mmap_pgprot(struct device *dev, pgprot_t prot,
+ unsigned long attrs)
{
- struct scatterlist *sg;
- int i;
-
- if (!is_device_dma_coherent(dev) &&
- (attrs & DMA_ATTR_SKIP_CPU_SYNC) == 0)
- for_each_sg(sgl, sg, nelems, i)
- __dma_unmap_area(phys_to_virt(dma_to_phys(dev, sg->dma_address)),
- sg->length, dir);
- swiotlb_unmap_sg_attrs(dev, sgl, nelems, dir, attrs);
+ if (!dev_is_dma_coherent(dev) || (attrs & DMA_ATTR_WRITE_COMBINE))
+ return pgprot_writecombine(prot);
+ return prot;
}

-static void __swiotlb_sync_single_for_cpu(struct device *dev,
- dma_addr_t dev_addr, size_t size,
- enum dma_data_direction dir)
+void arch_sync_dma_for_device(struct device *dev, phys_addr_t paddr,
+ size_t size, enum dma_data_direction dir)
{
- if (!is_device_dma_coherent(dev))
- __dma_unmap_area(phys_to_virt(dma_to_phys(dev, dev_addr)), size, dir);
- swiotlb_sync_single_for_cpu(dev, dev_addr, size, dir);
+ __dma_map_area(phys_to_virt(paddr), size, dir);
}

-static void __swiotlb_sync_single_for_device(struct device *dev,
- dma_addr_t dev_addr, size_t size,
- enum dma_data_direction dir)
+void arch_sync_dma_for_cpu(struct device *dev, phys_addr_t paddr,
+ size_t size, enum dma_data_direction dir)
{
- swiotlb_sync_single_for_device(dev, dev_addr, size, dir);
- if (!is_device_dma_coherent(dev))
- __dma_map_area(phys_to_virt(dma_to_phys(dev, dev_addr)), size, dir);
+ __dma_unmap_area(phys_to_virt(paddr), size, dir);
}

-static void __swiotlb_sync_sg_for_cpu(struct device *dev,
- struct scatterlist *sgl, int nelems,
- enum dma_data_direction dir)
+static int __swiotlb_get_sgtable_page(struct sg_table *sgt,
+ struct page *page, size_t size)
{
- struct scatterlist *sg;
- int i;
-
- if (!is_device_dma_coherent(dev))
- for_each_sg(sgl, sg, nelems, i)
- __dma_unmap_area(phys_to_virt(dma_to_phys(dev, sg->dma_address)),
- sg->length, dir);
- swiotlb_sync_sg_for_cpu(dev, sgl, nelems, dir);
-}
+ int ret = sg_alloc_table(sgt, 1, GFP_KERNEL);

-static void __swiotlb_sync_sg_for_device(struct device *dev,
- struct scatterlist *sgl, int nelems,
- enum dma_data_direction dir)
-{
- struct scatterlist *sg;
- int i;
+ if (!ret)
+ sg_set_page(sgt->sgl, page, PAGE_ALIGN(size), 0);

- swiotlb_sync_sg_for_device(dev, sgl, nelems, dir);
- if (!is_device_dma_coherent(dev))
- for_each_sg(sgl, sg, nelems, i)
- __dma_map_area(phys_to_virt(dma_to_phys(dev, sg->dma_address)),
- sg->length, dir);
+ return ret;
}

static int __swiotlb_mmap_pfn(struct vm_area_struct *vma,
@@ -277,74 +187,6 @@ static int __swiotlb_mmap_pfn(struct vm_area_struct *vma,
return ret;
}

-static int __swiotlb_mmap(struct device *dev,
- struct vm_area_struct *vma,
- void *cpu_addr, dma_addr_t dma_addr, size_t size,
- unsigned long attrs)
-{
- int ret;
- unsigned long pfn = dma_to_phys(dev, dma_addr) >> PAGE_SHIFT;
-
- vma->vm_page_prot = __get_dma_pgprot(attrs, vma->vm_page_prot,
- is_device_dma_coherent(dev));
-
- if (dma_mmap_from_dev_coherent(dev, vma, cpu_addr, size, &ret))
- return ret;
-
- return __swiotlb_mmap_pfn(vma, pfn, size);
-}
-
-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_get_sgtable(struct device *dev, struct sg_table *sgt,
- void *cpu_addr, dma_addr_t handle, size_t size,
- unsigned long attrs)
-{
- struct page *page = phys_to_page(dma_to_phys(dev, handle));
-
- return __swiotlb_get_sgtable_page(sgt, page, size);
-}
-
-static int __swiotlb_dma_supported(struct device *hwdev, u64 mask)
-{
- if (swiotlb)
- return swiotlb_dma_supported(hwdev, mask);
- return 1;
-}
-
-static int __swiotlb_dma_mapping_error(struct device *hwdev, dma_addr_t addr)
-{
- if (swiotlb)
- return dma_direct_mapping_error(hwdev, addr);
- return 0;
-}
-
-static const struct dma_map_ops arm64_swiotlb_dma_ops = {
- .alloc = __dma_alloc,
- .free = __dma_free,
- .mmap = __swiotlb_mmap,
- .get_sgtable = __swiotlb_get_sgtable,
- .map_page = __swiotlb_map_page,
- .unmap_page = __swiotlb_unmap_page,
- .map_sg = __swiotlb_map_sg_attrs,
- .unmap_sg = __swiotlb_unmap_sg_attrs,
- .sync_single_for_cpu = __swiotlb_sync_single_for_cpu,
- .sync_single_for_device = __swiotlb_sync_single_for_device,
- .sync_sg_for_cpu = __swiotlb_sync_sg_for_cpu,
- .sync_sg_for_device = __swiotlb_sync_sg_for_device,
- .dma_supported = __swiotlb_dma_supported,
- .mapping_error = __swiotlb_dma_mapping_error,
-};
-
static int __init atomic_pool_init(void)
{
pgprot_t prot = __pgprot(PROT_NORMAL_NC);
@@ -500,10 +342,6 @@ EXPORT_SYMBOL(dummy_dma_ops);

static int __init arm64_dma_init(void)
{
- if (swiotlb_force == SWIOTLB_FORCE ||
- max_pfn > (arm64_dma_phys_limit >> PAGE_SHIFT))
- swiotlb = 1;
-
WARN_TAINT(ARCH_DMA_MINALIGN < cache_line_size(),
TAINT_CPU_OUT_OF_SPEC,
"ARCH_DMA_MINALIGN smaller than CTR_EL0.CWG (%d < %d)",
@@ -528,7 +366,7 @@ static void *__iommu_alloc_attrs(struct device *dev, size_t size,
dma_addr_t *handle, gfp_t gfp,
unsigned long attrs)
{
- bool coherent = is_device_dma_coherent(dev);
+ bool coherent = dev_is_dma_coherent(dev);
int ioprot = dma_info_to_prot(DMA_BIDIRECTIONAL, coherent, attrs);
size_t iosize = size;
void *addr;
@@ -569,7 +407,7 @@ static void *__iommu_alloc_attrs(struct device *dev, size_t size,
addr = NULL;
}
} else if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {
- pgprot_t prot = __get_dma_pgprot(attrs, PAGE_KERNEL, coherent);
+ pgprot_t prot = arch_dma_mmap_pgprot(dev, PAGE_KERNEL, attrs);
struct page *page;

page = dma_alloc_from_contiguous(dev, size >> PAGE_SHIFT,
@@ -596,7 +434,7 @@ static void *__iommu_alloc_attrs(struct device *dev, size_t size,
size >> PAGE_SHIFT);
}
} else {
- pgprot_t prot = __get_dma_pgprot(attrs, PAGE_KERNEL, coherent);
+ pgprot_t prot = arch_dma_mmap_pgprot(dev, PAGE_KERNEL, attrs);
struct page **pages;

pages = iommu_dma_alloc(dev, iosize, gfp, attrs, ioprot,
@@ -658,8 +496,7 @@ static int __iommu_mmap_attrs(struct device *dev, struct vm_area_struct *vma,
struct vm_struct *area;
int ret;

- vma->vm_page_prot = __get_dma_pgprot(attrs, vma->vm_page_prot,
- is_device_dma_coherent(dev));
+ 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;
@@ -709,11 +546,11 @@ static void __iommu_sync_single_for_cpu(struct device *dev,
{
phys_addr_t phys;

- if (is_device_dma_coherent(dev))
+ if (dev_is_dma_coherent(dev))
return;

phys = iommu_iova_to_phys(iommu_get_domain_for_dev(dev), dev_addr);
- __dma_unmap_area(phys_to_virt(phys), size, dir);
+ arch_sync_dma_for_cpu(dev, phys, size, dir);
}

static void __iommu_sync_single_for_device(struct device *dev,
@@ -722,11 +559,11 @@ static void __iommu_sync_single_for_device(struct device *dev,
{
phys_addr_t phys;

- if (is_device_dma_coherent(dev))
+ if (dev_is_dma_coherent(dev))
return;

phys = iommu_iova_to_phys(iommu_get_domain_for_dev(dev), dev_addr);
- __dma_map_area(phys_to_virt(phys), size, dir);
+ arch_sync_dma_for_device(dev, phys, size, dir);
}

static dma_addr_t __iommu_map_page(struct device *dev, struct page *page,
@@ -734,7 +571,7 @@ static dma_addr_t __iommu_map_page(struct device *dev, struct page *page,
enum dma_data_direction dir,
unsigned long attrs)
{
- bool coherent = is_device_dma_coherent(dev);
+ 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);

@@ -762,11 +599,11 @@ static void __iommu_sync_sg_for_cpu(struct device *dev,
struct scatterlist *sg;
int i;

- if (is_device_dma_coherent(dev))
+ if (dev_is_dma_coherent(dev))
return;

for_each_sg(sgl, sg, nelems, i)
- __dma_unmap_area(sg_virt(sg), sg->length, dir);
+ arch_sync_dma_for_cpu(dev, sg_phys(sg), sg->length, dir);
}

static void __iommu_sync_sg_for_device(struct device *dev,
@@ -776,18 +613,18 @@ static void __iommu_sync_sg_for_device(struct device *dev,
struct scatterlist *sg;
int i;

- if (is_device_dma_coherent(dev))
+ if (dev_is_dma_coherent(dev))
return;

for_each_sg(sgl, sg, nelems, i)
- __dma_map_area(sg_virt(sg), sg->length, dir);
+ 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 = is_device_dma_coherent(dev);
+ bool coherent = dev_is_dma_coherent(dev);

if ((attrs & DMA_ATTR_SKIP_CPU_SYNC) == 0)
__iommu_sync_sg_for_device(dev, sgl, nelems, dir);
@@ -879,9 +716,9 @@ void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
const struct iommu_ops *iommu, bool coherent)
{
if (!dev->dma_ops)
- dev->dma_ops = &arm64_swiotlb_dma_ops;
+ dev->dma_ops = &swiotlb_dma_ops;

- dev->archdata.dma_coherent = coherent;
+ dev->dma_coherent = coherent;
__iommu_setup_dma_ops(dev, dma_base, size, iommu);

#ifdef CONFIG_XEN
--
2.19.0
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