arc dma mapping cleanups/fixes and generic noncohernt dma code

arc dma mapping cleanups/fixes and generic noncohernt dma code

[Christoph Hellwig]

Hi all,

this series continues consolidating the dma-mapping code, with a focus
on architectures that do not (always) provide cache coherence for DMA.
Three architectures (arm, mips and powerpc) are still left to be
converted later due to complexity of their dma ops selection.

The dma-noncoherent ops calls the dma-direct ops for the actual
translation of streaming mappins and allow the architecture to provide
any cache flushing required for cpu to device and/or device to cpu
ownership transfers.  The dma coherent allocator is for now still left
entirely to architecture supplied implementations due the amount of
variations.  Hopefully we can do some consolidation for them later on
as well.

Because this series sits on top of two previously submitted series
a git tree might be useful to actually test it.  It is provided here:

    git://git.infradead.org/users/hch/misc.git arc-dma

Gitweb:

    http://git.infradead.org/users/hch/misc.git/shortlog/refs/heads/arc-dma

Changes since previous bigger series:
 - take the offset into account in noncoherent_dma_map_page (Alexey Brodkin)
 - fix dma directions in arc (Alexey Brodkin)
 - split arc changes into smaller patches

arc dma mapping cleanups/fixes and generic noncohernt dma code

[Christoph Hellwig]

Hi all,

this series continues consolidating the dma-mapping code, with a focus
on architectures that do not (always) provide cache coherence for DMA.
Three architectures (arm, mips and powerpc) are still left to be
converted later due to complexity of their dma ops selection.

The dma-noncoherent ops calls the dma-direct ops for the actual
translation of streaming mappins and allow the architecture to provide
any cache flushing required for cpu to device and/or device to cpu
ownership transfers.  The dma coherent allocator is for now still left
entirely to architecture supplied implementations due the amount of
variations.  Hopefully we can do some consolidation for them later on
as well.

Because this series sits on top of two previously submitted series
a git tree might be useful to actually test it.  It is provided here:

    git://git.infradead.org/users/hch/misc.git arc-dma

Gitweb:

    http://git.infradead.org/users/hch/misc.git/shortlog/refs/heads/arc-dma

Changes since previous bigger series:
 - take the offset into account in noncoherent_dma_map_page (Alexey Brodkin)
 - fix dma directions in arc (Alexey Brodkin)
 - split arc changes into smaller patches

[PATCH 1/6] dma-mapping: simplify Kconfig dependencies

[Christoph Hellwig]

ARCH_DMA_ADDR_T_64BIT is always true for 64-bit architectures now, so we
can skip the clause requiring it.  'n' is the default default, so no need
to explicitly state it.

Signed-off-by: Christoph Hellwig <hch at lst.de>
---
 lib/Kconfig | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/lib/Kconfig b/lib/Kconfig
index 1d84e61cccfe..6c4e9d0ce5d1 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -443,13 +443,11 @@ config IOMMU_HELPER
 
 config DMA_DIRECT_OPS
 	bool
-	depends on HAS_DMA && (!64BIT || ARCH_DMA_ADDR_T_64BIT)
-	default n
+	depends on HAS_DMA
 
 config DMA_VIRT_OPS
 	bool
-	depends on HAS_DMA && (!64BIT || ARCH_DMA_ADDR_T_64BIT)
-	default n
+	depends on HAS_DMA
 
 config SWIOTLB
 	bool
-- 
2.17.0

[PATCH 1/6] dma-mapping: simplify Kconfig dependencies

[Christoph Hellwig]

ARCH_DMA_ADDR_T_64BIT is always true for 64-bit architectures now, so we
can skip the clause requiring it.  'n' is the default default, so no need
to explicitly state it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 lib/Kconfig | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/lib/Kconfig b/lib/Kconfig
index 1d84e61cccfe..6c4e9d0ce5d1 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -443,13 +443,11 @@ config IOMMU_HELPER
 
 config DMA_DIRECT_OPS
 	bool
-	depends on HAS_DMA && (!64BIT || ARCH_DMA_ADDR_T_64BIT)
-	default n
+	depends on HAS_DMA
 
 config DMA_VIRT_OPS
 	bool
-	depends on HAS_DMA && (!64BIT || ARCH_DMA_ADDR_T_64BIT)
-	default n
+	depends on HAS_DMA
 
 config SWIOTLB
 	bool
-- 
2.17.0

[PATCH 2/6] dma-mapping: provide a generic dma-noncoherent implementation

[Christoph Hellwig]

Add a new dma_map_ops implementation that uses dma-direct for the
address mapping of streaming mappings, and which requires arch-specific
implemenations of coherent allocate/free.

Architectures have to provide flushing helpers to ownership trasnfers
to the device and/or CPU, and can provide optional implementations of
the coherent mmap functionality, and the cache_flush routines for
non-coherent long term allocations.

Signed-off-by: Christoph Hellwig <hch at lst.de>
---
 MAINTAINERS                       |   2 +
 include/asm-generic/dma-mapping.h |   9 +++
 include/linux/dma-direct.h        |   7 +-
 include/linux/dma-mapping.h       |   1 +
 include/linux/dma-noncoherent.h   |  47 ++++++++++++++
 lib/Kconfig                       |  20 ++++++
 lib/Makefile                      |   1 +
 lib/dma-direct.c                  |   8 +--
 lib/dma-noncoherent.c             | 102 ++++++++++++++++++++++++++++++
 9 files changed, 192 insertions(+), 5 deletions(-)
 create mode 100644 include/linux/dma-noncoherent.h
 create mode 100644 lib/dma-noncoherent.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 79bb02ff812f..08d0d15d4958 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -4334,12 +4334,14 @@ W:	http://git.infradead.org/users/hch/dma-mapping.git
 S:	Supported
 F:	lib/dma-debug.c
 F:	lib/dma-direct.c
+F:	lib/dma-noncoherent.c
 F:	lib/dma-virt.c
 F:	drivers/base/dma-mapping.c
 F:	drivers/base/dma-coherent.c
 F:	include/asm-generic/dma-mapping.h
 F:	include/linux/dma-direct.h
 F:	include/linux/dma-mapping.h
+F:	include/linux/dma-noncoherent.h
 
 DME1737 HARDWARE MONITOR DRIVER
 M:	Juerg Haefliger <juergh at gmail.com>
diff --git a/include/asm-generic/dma-mapping.h b/include/asm-generic/dma-mapping.h
index 880a292d792f..ad2868263867 100644
--- a/include/asm-generic/dma-mapping.h
+++ b/include/asm-generic/dma-mapping.h
@@ -4,7 +4,16 @@
 
 static inline const struct dma_map_ops *get_arch_dma_ops(struct bus_type *bus)
 {
+	/*
+	 * Use the non-coherent ops if available.  If an architecture wants a
+	 * more fine-grained selection of operations it will have to implement
+	 * get_arch_dma_ops itself or use the per-device dma_ops.
+	 */
+#ifdef CONFIG_DMA_NONCOHERENT_OPS
+	return &dma_noncoherent_ops;
+#else
 	return &dma_direct_ops;
+#endif
 }
 
 #endif /* _ASM_GENERIC_DMA_MAPPING_H */
diff --git a/include/linux/dma-direct.h b/include/linux/dma-direct.h
index 53ad6a47f513..8d9f33febde5 100644
--- a/include/linux/dma-direct.h
+++ b/include/linux/dma-direct.h
@@ -59,6 +59,11 @@ void *dma_direct_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
 		gfp_t gfp, unsigned long attrs);
 void dma_direct_free(struct device *dev, size_t size, void *cpu_addr,
 		dma_addr_t dma_addr, unsigned long attrs);
+dma_addr_t dma_direct_map_page(struct device *dev, struct page *page,
+		unsigned long offset, size_t size, enum dma_data_direction dir,
+		unsigned long attrs);
+int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl, int nents,
+		enum dma_data_direction dir, unsigned long attrs);
 int dma_direct_supported(struct device *dev, u64 mask);
-
+int dma_direct_mapping_error(struct device *dev, dma_addr_t dma_addr);
 #endif /* _LINUX_DMA_DIRECT_H */
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index 25a9a2b04f78..4be070df5fc5 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -136,6 +136,7 @@ struct dma_map_ops {
 };
 
 extern const struct dma_map_ops dma_direct_ops;
+extern const struct dma_map_ops dma_noncoherent_ops;
 extern const struct dma_map_ops dma_virt_ops;
 
 #define DMA_BIT_MASK(n)	(((n) == 64) ? ~0ULL : ((1ULL<<(n))-1))
diff --git a/include/linux/dma-noncoherent.h b/include/linux/dma-noncoherent.h
new file mode 100644
index 000000000000..10b2654d549b
--- /dev/null
+++ b/include/linux/dma-noncoherent.h
@@ -0,0 +1,47 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_DMA_NONCOHERENT_H
+#define _LINUX_DMA_NONCOHERENT_H 1
+
+#include <linux/dma-mapping.h>
+
+void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
+		gfp_t gfp, unsigned long attrs);
+void arch_dma_free(struct device *dev, size_t size, void *cpu_addr,
+		dma_addr_t dma_addr, unsigned long attrs);
+
+#ifdef CONFIG_DMA_NONCOHERENT_MMAP
+int arch_dma_mmap(struct device *dev, struct vm_area_struct *vma,
+		void *cpu_addr, dma_addr_t dma_addr, size_t size,
+		unsigned long attrs);
+#else
+#define arch_dma_mmap NULL
+#endif /* CONFIG_DMA_NONCOHERENT_MMAP */
+
+#ifdef CONFIG_DMA_NONCOHERENT_CACHE_SYNC
+void arch_dma_cache_sync(struct device *dev, void *vaddr, size_t size,
+		enum dma_data_direction direction);
+#else
+#define arch_dma_cache_sync NULL
+#endif /* CONFIG_DMA_NONCOHERENT_CACHE_SYNC */
+
+#ifdef CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE
+void arch_sync_dma_for_device(struct device *dev, phys_addr_t paddr,
+		size_t size, enum dma_data_direction dir);
+#else
+static inline void arch_sync_dma_for_device(struct device *dev,
+		phys_addr_t paddr, size_t size, enum dma_data_direction dir)
+{
+}
+#endif /* ARCH_HAS_SYNC_DMA_FOR_DEVICE */
+
+#ifdef CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU
+void arch_sync_dma_for_cpu(struct device *dev, phys_addr_t paddr,
+		size_t size, enum dma_data_direction dir);
+#else
+static inline void arch_sync_dma_for_cpu(struct device *dev,
+		phys_addr_t paddr, size_t size, enum dma_data_direction dir)
+{
+}
+#endif /* ARCH_HAS_SYNC_DMA_FOR_CPU */
+
+#endif /* _LINUX_DMA_NONCOHERENT_H */
diff --git a/lib/Kconfig b/lib/Kconfig
index 6c4e9d0ce5d1..7a913937888b 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -441,10 +441,30 @@ config ARCH_DMA_ADDR_T_64BIT
 config IOMMU_HELPER
 	bool
 
+config ARCH_HAS_SYNC_DMA_FOR_DEVICE
+	bool
+
+config ARCH_HAS_SYNC_DMA_FOR_CPU
+	bool
+	select NEED_DMA_MAP_STATE
+
 config DMA_DIRECT_OPS
 	bool
 	depends on HAS_DMA
 
+config DMA_NONCOHERENT_OPS
+	bool
+	depends on HAS_DMA
+	select DMA_DIRECT_OPS
+
+config DMA_NONCOHERENT_MMAP
+	bool
+	depends on DMA_NONCOHERENT_OPS
+
+config DMA_NONCOHERENT_CACHE_SYNC
+	bool
+	depends on DMA_NONCOHERENT_OPS
+
 config DMA_VIRT_OPS
 	bool
 	depends on HAS_DMA
diff --git a/lib/Makefile b/lib/Makefile
index 94203b5eecd4..9f18c8152281 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -30,6 +30,7 @@ lib-$(CONFIG_PRINTK) += dump_stack.o
 lib-$(CONFIG_MMU) += ioremap.o
 lib-$(CONFIG_SMP) += cpumask.o
 lib-$(CONFIG_DMA_DIRECT_OPS) += dma-direct.o
+lib-$(CONFIG_DMA_NONCOHERENT_OPS) += dma-noncoherent.o
 lib-$(CONFIG_DMA_VIRT_OPS) += dma-virt.o
 
 lib-y	+= kobject.o klist.o
diff --git a/lib/dma-direct.c b/lib/dma-direct.c
index df9e726e0712..b824eb218782 100644
--- a/lib/dma-direct.c
+++ b/lib/dma-direct.c
@@ -128,7 +128,7 @@ void dma_direct_free(struct device *dev, size_t size, void *cpu_addr,
 		free_pages((unsigned long)cpu_addr, page_order);
 }
 
-static dma_addr_t dma_direct_map_page(struct device *dev, struct page *page,
+dma_addr_t dma_direct_map_page(struct device *dev, struct page *page,
 		unsigned long offset, size_t size, enum dma_data_direction dir,
 		unsigned long attrs)
 {
@@ -139,8 +139,8 @@ static dma_addr_t dma_direct_map_page(struct device *dev, struct page *page,
 	return dma_addr;
 }
 
-static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl,
-		int nents, enum dma_data_direction dir, unsigned long attrs)
+int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl, int nents,
+		enum dma_data_direction dir, unsigned long attrs)
 {
 	int i;
 	struct scatterlist *sg;
@@ -175,7 +175,7 @@ int dma_direct_supported(struct device *dev, u64 mask)
 	return 1;
 }
 
-static int dma_direct_mapping_error(struct device *dev, dma_addr_t dma_addr)
+int dma_direct_mapping_error(struct device *dev, dma_addr_t dma_addr)
 {
 	return dma_addr == DIRECT_MAPPING_ERROR;
 }
diff --git a/lib/dma-noncoherent.c b/lib/dma-noncoherent.c
new file mode 100644
index 000000000000..79e9a757387f
--- /dev/null
+++ b/lib/dma-noncoherent.c
@@ -0,0 +1,102 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2018 Christoph Hellwig.
+ *
+ * DMA operations that map physical memory directly without providing cache
+ * coherence.
+ */
+#include <linux/export.h>
+#include <linux/mm.h>
+#include <linux/dma-direct.h>
+#include <linux/dma-noncoherent.h>
+#include <linux/scatterlist.h>
+
+static void dma_noncoherent_sync_single_for_device(struct device *dev,
+		dma_addr_t addr, size_t size, enum dma_data_direction dir)
+{
+	arch_sync_dma_for_device(dev, dma_to_phys(dev, addr), size, dir);
+}
+
+static void dma_noncoherent_sync_sg_for_device(struct device *dev,
+		struct scatterlist *sgl, int nents, enum dma_data_direction dir)
+{
+	struct scatterlist *sg;
+	int i;
+
+	for_each_sg(sgl, sg, nents, i)
+		arch_sync_dma_for_device(dev, sg_phys(sg), sg->length, dir);
+}
+
+static dma_addr_t dma_noncoherent_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 addr;
+
+	addr = dma_direct_map_page(dev, page, offset, size, dir, attrs);
+	if (!dma_mapping_error(dev, addr) && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+		arch_sync_dma_for_device(dev, page_to_phys(page) + offset,
+				size, dir);
+	return addr;
+}
+
+static int dma_noncoherent_map_sg(struct device *dev, struct scatterlist *sgl,
+		int nents, enum dma_data_direction dir, unsigned long attrs)
+{
+	nents = dma_direct_map_sg(dev, sgl, nents, dir, attrs);
+	if (nents > 0 && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+		dma_noncoherent_sync_sg_for_device(dev, sgl, nents, dir);
+	return nents;
+}
+
+#ifdef CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU
+static void dma_noncoherent_sync_single_for_cpu(struct device *dev,
+		dma_addr_t addr, size_t size, enum dma_data_direction dir)
+{
+	arch_sync_dma_for_cpu(dev, dma_to_phys(dev, addr), size, dir);
+}
+
+static void dma_noncoherent_sync_sg_for_cpu(struct device *dev,
+		struct scatterlist *sgl, int nents, enum dma_data_direction dir)
+{
+	struct scatterlist *sg;
+	int i;
+
+	for_each_sg(sgl, sg, nents, i)
+		arch_sync_dma_for_cpu(dev, sg_phys(sg), sg->length, dir);
+}
+
+static void dma_noncoherent_unmap_page(struct device *dev, dma_addr_t addr,
+		size_t size, enum dma_data_direction dir, unsigned long attrs)
+{
+	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+		dma_noncoherent_sync_single_for_cpu(dev, addr, size, dir);
+}
+
+static void dma_noncoherent_unmap_sg(struct device *dev, struct scatterlist *sgl,
+		int nents, enum dma_data_direction dir, unsigned long attrs)
+{
+	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+		dma_noncoherent_sync_sg_for_cpu(dev, sgl, nents, dir);
+}
+#endif
+
+const struct dma_map_ops dma_noncoherent_ops = {
+	.alloc			= arch_dma_alloc,
+	.free			= arch_dma_free,
+	.mmap			= arch_dma_mmap,
+	.sync_single_for_device	= dma_noncoherent_sync_single_for_device,
+	.sync_sg_for_device	= dma_noncoherent_sync_sg_for_device,
+	.map_page		= dma_noncoherent_map_page,
+	.map_sg			= dma_noncoherent_map_sg,
+#ifdef CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU
+	.sync_single_for_cpu	= dma_noncoherent_sync_single_for_cpu,
+	.sync_sg_for_cpu	= dma_noncoherent_sync_sg_for_cpu,
+	.unmap_page		= dma_noncoherent_unmap_page,
+	.unmap_sg		= dma_noncoherent_unmap_sg,
+#endif
+	.dma_supported		= dma_direct_supported,
+	.mapping_error		= dma_direct_mapping_error,
+	.cache_sync		= arch_dma_cache_sync,
+};
+EXPORT_SYMBOL(dma_noncoherent_ops);
-- 
2.17.0

[PATCH 2/6] dma-mapping: provide a generic dma-noncoherent implementation

[Christoph Hellwig]

Add a new dma_map_ops implementation that uses dma-direct for the
address mapping of streaming mappings, and which requires arch-specific
implemenations of coherent allocate/free.

Architectures have to provide flushing helpers to ownership trasnfers
to the device and/or CPU, and can provide optional implementations of
the coherent mmap functionality, and the cache_flush routines for
non-coherent long term allocations.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 MAINTAINERS                       |   2 +
 include/asm-generic/dma-mapping.h |   9 +++
 include/linux/dma-direct.h        |   7 +-
 include/linux/dma-mapping.h       |   1 +
 include/linux/dma-noncoherent.h   |  47 ++++++++++++++
 lib/Kconfig                       |  20 ++++++
 lib/Makefile                      |   1 +
 lib/dma-direct.c                  |   8 +--
 lib/dma-noncoherent.c             | 102 ++++++++++++++++++++++++++++++
 9 files changed, 192 insertions(+), 5 deletions(-)
 create mode 100644 include/linux/dma-noncoherent.h
 create mode 100644 lib/dma-noncoherent.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 79bb02ff812f..08d0d15d4958 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -4334,12 +4334,14 @@ W:	http://git.infradead.org/users/hch/dma-mapping.git
 S:	Supported
 F:	lib/dma-debug.c
 F:	lib/dma-direct.c
+F:	lib/dma-noncoherent.c
 F:	lib/dma-virt.c
 F:	drivers/base/dma-mapping.c
 F:	drivers/base/dma-coherent.c
 F:	include/asm-generic/dma-mapping.h
 F:	include/linux/dma-direct.h
 F:	include/linux/dma-mapping.h
+F:	include/linux/dma-noncoherent.h
 
 DME1737 HARDWARE MONITOR DRIVER
 M:	Juerg Haefliger <juergh@gmail.com>
diff --git a/include/asm-generic/dma-mapping.h b/include/asm-generic/dma-mapping.h
index 880a292d792f..ad2868263867 100644
--- a/include/asm-generic/dma-mapping.h
+++ b/include/asm-generic/dma-mapping.h
@@ -4,7 +4,16 @@
 
 static inline const struct dma_map_ops *get_arch_dma_ops(struct bus_type *bus)
 {
+	/*
+	 * Use the non-coherent ops if available.  If an architecture wants a
+	 * more fine-grained selection of operations it will have to implement
+	 * get_arch_dma_ops itself or use the per-device dma_ops.
+	 */
+#ifdef CONFIG_DMA_NONCOHERENT_OPS
+	return &dma_noncoherent_ops;
+#else
 	return &dma_direct_ops;
+#endif
 }
 
 #endif /* _ASM_GENERIC_DMA_MAPPING_H */
diff --git a/include/linux/dma-direct.h b/include/linux/dma-direct.h
index 53ad6a47f513..8d9f33febde5 100644
--- a/include/linux/dma-direct.h
+++ b/include/linux/dma-direct.h
@@ -59,6 +59,11 @@ void *dma_direct_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
 		gfp_t gfp, unsigned long attrs);
 void dma_direct_free(struct device *dev, size_t size, void *cpu_addr,
 		dma_addr_t dma_addr, unsigned long attrs);
+dma_addr_t dma_direct_map_page(struct device *dev, struct page *page,
+		unsigned long offset, size_t size, enum dma_data_direction dir,
+		unsigned long attrs);
+int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl, int nents,
+		enum dma_data_direction dir, unsigned long attrs);
 int dma_direct_supported(struct device *dev, u64 mask);
-
+int dma_direct_mapping_error(struct device *dev, dma_addr_t dma_addr);
 #endif /* _LINUX_DMA_DIRECT_H */
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index 25a9a2b04f78..4be070df5fc5 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -136,6 +136,7 @@ struct dma_map_ops {
 };
 
 extern const struct dma_map_ops dma_direct_ops;
+extern const struct dma_map_ops dma_noncoherent_ops;
 extern const struct dma_map_ops dma_virt_ops;
 
 #define DMA_BIT_MASK(n)	(((n) == 64) ? ~0ULL : ((1ULL<<(n))-1))
diff --git a/include/linux/dma-noncoherent.h b/include/linux/dma-noncoherent.h
new file mode 100644
index 000000000000..10b2654d549b
--- /dev/null
+++ b/include/linux/dma-noncoherent.h
@@ -0,0 +1,47 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_DMA_NONCOHERENT_H
+#define _LINUX_DMA_NONCOHERENT_H 1
+
+#include <linux/dma-mapping.h>
+
+void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
+		gfp_t gfp, unsigned long attrs);
+void arch_dma_free(struct device *dev, size_t size, void *cpu_addr,
+		dma_addr_t dma_addr, unsigned long attrs);
+
+#ifdef CONFIG_DMA_NONCOHERENT_MMAP
+int arch_dma_mmap(struct device *dev, struct vm_area_struct *vma,
+		void *cpu_addr, dma_addr_t dma_addr, size_t size,
+		unsigned long attrs);
+#else
+#define arch_dma_mmap NULL
+#endif /* CONFIG_DMA_NONCOHERENT_MMAP */
+
+#ifdef CONFIG_DMA_NONCOHERENT_CACHE_SYNC
+void arch_dma_cache_sync(struct device *dev, void *vaddr, size_t size,
+		enum dma_data_direction direction);
+#else
+#define arch_dma_cache_sync NULL
+#endif /* CONFIG_DMA_NONCOHERENT_CACHE_SYNC */
+
+#ifdef CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE
+void arch_sync_dma_for_device(struct device *dev, phys_addr_t paddr,
+		size_t size, enum dma_data_direction dir);
+#else
+static inline void arch_sync_dma_for_device(struct device *dev,
+		phys_addr_t paddr, size_t size, enum dma_data_direction dir)
+{
+}
+#endif /* ARCH_HAS_SYNC_DMA_FOR_DEVICE */
+
+#ifdef CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU
+void arch_sync_dma_for_cpu(struct device *dev, phys_addr_t paddr,
+		size_t size, enum dma_data_direction dir);
+#else
+static inline void arch_sync_dma_for_cpu(struct device *dev,
+		phys_addr_t paddr, size_t size, enum dma_data_direction dir)
+{
+}
+#endif /* ARCH_HAS_SYNC_DMA_FOR_CPU */
+
+#endif /* _LINUX_DMA_NONCOHERENT_H */
diff --git a/lib/Kconfig b/lib/Kconfig
index 6c4e9d0ce5d1..7a913937888b 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -441,10 +441,30 @@ config ARCH_DMA_ADDR_T_64BIT
 config IOMMU_HELPER
 	bool
 
+config ARCH_HAS_SYNC_DMA_FOR_DEVICE
+	bool
+
+config ARCH_HAS_SYNC_DMA_FOR_CPU
+	bool
+	select NEED_DMA_MAP_STATE
+
 config DMA_DIRECT_OPS
 	bool
 	depends on HAS_DMA
 
+config DMA_NONCOHERENT_OPS
+	bool
+	depends on HAS_DMA
+	select DMA_DIRECT_OPS
+
+config DMA_NONCOHERENT_MMAP
+	bool
+	depends on DMA_NONCOHERENT_OPS
+
+config DMA_NONCOHERENT_CACHE_SYNC
+	bool
+	depends on DMA_NONCOHERENT_OPS
+
 config DMA_VIRT_OPS
 	bool
 	depends on HAS_DMA
diff --git a/lib/Makefile b/lib/Makefile
index 94203b5eecd4..9f18c8152281 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -30,6 +30,7 @@ lib-$(CONFIG_PRINTK) += dump_stack.o
 lib-$(CONFIG_MMU) += ioremap.o
 lib-$(CONFIG_SMP) += cpumask.o
 lib-$(CONFIG_DMA_DIRECT_OPS) += dma-direct.o
+lib-$(CONFIG_DMA_NONCOHERENT_OPS) += dma-noncoherent.o
 lib-$(CONFIG_DMA_VIRT_OPS) += dma-virt.o
 
 lib-y	+= kobject.o klist.o
diff --git a/lib/dma-direct.c b/lib/dma-direct.c
index df9e726e0712..b824eb218782 100644
--- a/lib/dma-direct.c
+++ b/lib/dma-direct.c
@@ -128,7 +128,7 @@ void dma_direct_free(struct device *dev, size_t size, void *cpu_addr,
 		free_pages((unsigned long)cpu_addr, page_order);
 }
 
-static dma_addr_t dma_direct_map_page(struct device *dev, struct page *page,
+dma_addr_t dma_direct_map_page(struct device *dev, struct page *page,
 		unsigned long offset, size_t size, enum dma_data_direction dir,
 		unsigned long attrs)
 {
@@ -139,8 +139,8 @@ static dma_addr_t dma_direct_map_page(struct device *dev, struct page *page,
 	return dma_addr;
 }
 
-static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl,
-		int nents, enum dma_data_direction dir, unsigned long attrs)
+int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl, int nents,
+		enum dma_data_direction dir, unsigned long attrs)
 {
 	int i;
 	struct scatterlist *sg;
@@ -175,7 +175,7 @@ int dma_direct_supported(struct device *dev, u64 mask)
 	return 1;
 }
 
-static int dma_direct_mapping_error(struct device *dev, dma_addr_t dma_addr)
+int dma_direct_mapping_error(struct device *dev, dma_addr_t dma_addr)
 {
 	return dma_addr == DIRECT_MAPPING_ERROR;
 }
diff --git a/lib/dma-noncoherent.c b/lib/dma-noncoherent.c
new file mode 100644
index 000000000000..79e9a757387f
--- /dev/null
+++ b/lib/dma-noncoherent.c
@@ -0,0 +1,102 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2018 Christoph Hellwig.
+ *
+ * DMA operations that map physical memory directly without providing cache
+ * coherence.
+ */
+#include <linux/export.h>
+#include <linux/mm.h>
+#include <linux/dma-direct.h>
+#include <linux/dma-noncoherent.h>
+#include <linux/scatterlist.h>
+
+static void dma_noncoherent_sync_single_for_device(struct device *dev,
+		dma_addr_t addr, size_t size, enum dma_data_direction dir)
+{
+	arch_sync_dma_for_device(dev, dma_to_phys(dev, addr), size, dir);
+}
+
+static void dma_noncoherent_sync_sg_for_device(struct device *dev,
+		struct scatterlist *sgl, int nents, enum dma_data_direction dir)
+{
+	struct scatterlist *sg;
+	int i;
+
+	for_each_sg(sgl, sg, nents, i)
+		arch_sync_dma_for_device(dev, sg_phys(sg), sg->length, dir);
+}
+
+static dma_addr_t dma_noncoherent_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 addr;
+
+	addr = dma_direct_map_page(dev, page, offset, size, dir, attrs);
+	if (!dma_mapping_error(dev, addr) && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+		arch_sync_dma_for_device(dev, page_to_phys(page) + offset,
+				size, dir);
+	return addr;
+}
+
+static int dma_noncoherent_map_sg(struct device *dev, struct scatterlist *sgl,
+		int nents, enum dma_data_direction dir, unsigned long attrs)
+{
+	nents = dma_direct_map_sg(dev, sgl, nents, dir, attrs);
+	if (nents > 0 && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+		dma_noncoherent_sync_sg_for_device(dev, sgl, nents, dir);
+	return nents;
+}
+
+#ifdef CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU
+static void dma_noncoherent_sync_single_for_cpu(struct device *dev,
+		dma_addr_t addr, size_t size, enum dma_data_direction dir)
+{
+	arch_sync_dma_for_cpu(dev, dma_to_phys(dev, addr), size, dir);
+}
+
+static void dma_noncoherent_sync_sg_for_cpu(struct device *dev,
+		struct scatterlist *sgl, int nents, enum dma_data_direction dir)
+{
+	struct scatterlist *sg;
+	int i;
+
+	for_each_sg(sgl, sg, nents, i)
+		arch_sync_dma_for_cpu(dev, sg_phys(sg), sg->length, dir);
+}
+
+static void dma_noncoherent_unmap_page(struct device *dev, dma_addr_t addr,
+		size_t size, enum dma_data_direction dir, unsigned long attrs)
+{
+	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+		dma_noncoherent_sync_single_for_cpu(dev, addr, size, dir);
+}
+
+static void dma_noncoherent_unmap_sg(struct device *dev, struct scatterlist *sgl,
+		int nents, enum dma_data_direction dir, unsigned long attrs)
+{
+	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+		dma_noncoherent_sync_sg_for_cpu(dev, sgl, nents, dir);
+}
+#endif
+
+const struct dma_map_ops dma_noncoherent_ops = {
+	.alloc			= arch_dma_alloc,
+	.free			= arch_dma_free,
+	.mmap			= arch_dma_mmap,
+	.sync_single_for_device	= dma_noncoherent_sync_single_for_device,
+	.sync_sg_for_device	= dma_noncoherent_sync_sg_for_device,
+	.map_page		= dma_noncoherent_map_page,
+	.map_sg			= dma_noncoherent_map_sg,
+#ifdef CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU
+	.sync_single_for_cpu	= dma_noncoherent_sync_single_for_cpu,
+	.sync_sg_for_cpu	= dma_noncoherent_sync_sg_for_cpu,
+	.unmap_page		= dma_noncoherent_unmap_page,
+	.unmap_sg		= dma_noncoherent_unmap_sg,
+#endif
+	.dma_supported		= dma_direct_supported,
+	.mapping_error		= dma_direct_mapping_error,
+	.cache_sync		= arch_dma_cache_sync,
+};
+EXPORT_SYMBOL(dma_noncoherent_ops);
-- 
2.17.0

[PATCH 3/6] arc: simplify arc_dma_sync_single_for_{cpu,device}

[Christoph Hellwig]

Remove the indirection through _dma_cache_sync.  Also move the functions
up a bit in the source file as we'll need them in more places soon.

Signed-off-by: Christoph Hellwig <hch at lst.de>
---
 arch/arc/mm/dma.c | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/arch/arc/mm/dma.c b/arch/arc/mm/dma.c
index 1dcc404b5aec..98e21ce526be 100644
--- a/arch/arc/mm/dma.c
+++ b/arch/arc/mm/dma.c
@@ -153,6 +153,18 @@ static void _dma_cache_sync(phys_addr_t paddr, size_t size,
 	}
 }
 
+static void arc_dma_sync_single_for_device(struct device *dev,
+		dma_addr_t dma_handle, size_t size, enum dma_data_direction dir)
+{
+	dma_cache_wback(dma_handle, size);
+}
+
+static void arc_dma_sync_single_for_cpu(struct device *dev,
+		dma_addr_t dma_handle, size_t size, enum dma_data_direction dir)
+{
+	dma_cache_inv(dma_handle, size);
+}
+
 /*
  * arc_dma_map_page - map a portion of a page for streaming DMA
  *
@@ -221,18 +233,6 @@ static void arc_dma_unmap_sg(struct device *dev, struct scatterlist *sg,
 				   attrs);
 }
 
-static void arc_dma_sync_single_for_cpu(struct device *dev,
-		dma_addr_t dma_handle, size_t size, enum dma_data_direction dir)
-{
-	_dma_cache_sync(dma_handle, size, DMA_FROM_DEVICE);
-}
-
-static void arc_dma_sync_single_for_device(struct device *dev,
-		dma_addr_t dma_handle, size_t size, enum dma_data_direction dir)
-{
-	_dma_cache_sync(dma_handle, size, DMA_TO_DEVICE);
-}
-
 static void arc_dma_sync_sg_for_cpu(struct device *dev,
 		struct scatterlist *sglist, int nelems,
 		enum dma_data_direction dir)
-- 
2.17.0

[PATCH 3/6] arc: simplify arc_dma_sync_single_for_{cpu,device}

[Christoph Hellwig]

Remove the indirection through _dma_cache_sync.  Also move the functions
up a bit in the source file as we'll need them in more places soon.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 arch/arc/mm/dma.c | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/arch/arc/mm/dma.c b/arch/arc/mm/dma.c
index 1dcc404b5aec..98e21ce526be 100644
--- a/arch/arc/mm/dma.c
+++ b/arch/arc/mm/dma.c
@@ -153,6 +153,18 @@ static void _dma_cache_sync(phys_addr_t paddr, size_t size,
 	}
 }
 
+static void arc_dma_sync_single_for_device(struct device *dev,
+		dma_addr_t dma_handle, size_t size, enum dma_data_direction dir)
+{
+	dma_cache_wback(dma_handle, size);
+}
+
+static void arc_dma_sync_single_for_cpu(struct device *dev,
+		dma_addr_t dma_handle, size_t size, enum dma_data_direction dir)
+{
+	dma_cache_inv(dma_handle, size);
+}
+
 /*
  * arc_dma_map_page - map a portion of a page for streaming DMA
  *
@@ -221,18 +233,6 @@ static void arc_dma_unmap_sg(struct device *dev, struct scatterlist *sg,
 				   attrs);
 }
 
-static void arc_dma_sync_single_for_cpu(struct device *dev,
-		dma_addr_t dma_handle, size_t size, enum dma_data_direction dir)
-{
-	_dma_cache_sync(dma_handle, size, DMA_FROM_DEVICE);
-}
-
-static void arc_dma_sync_single_for_device(struct device *dev,
-		dma_addr_t dma_handle, size_t size, enum dma_data_direction dir)
-{
-	_dma_cache_sync(dma_handle, size, DMA_TO_DEVICE);
-}
-
 static void arc_dma_sync_sg_for_cpu(struct device *dev,
 		struct scatterlist *sglist, int nelems,
 		enum dma_data_direction dir)
-- 
2.17.0

[PATCH 4/6] arc: fix arc_dma_sync_sg_for_{cpu,device}

[Christoph Hellwig]

These functions should perform the same functionality as calling
arc_dma_sync_single_for_{cpu,device} on each S/G list element.  Ensure
they actually do that by calling arc_dma_sync_single_for_{cpu,device}.
Otherwise we could be passing a different dir argument.

Signed-off-by: Christoph Hellwig <hch at lst.de>
---
 arch/arc/mm/dma.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/arc/mm/dma.c b/arch/arc/mm/dma.c
index 98e21ce526be..eafdbd2ad20a 100644
--- a/arch/arc/mm/dma.c
+++ b/arch/arc/mm/dma.c
@@ -241,7 +241,7 @@ static void arc_dma_sync_sg_for_cpu(struct device *dev,
 	struct scatterlist *sg;
 
 	for_each_sg(sglist, sg, nelems, i)
-		_dma_cache_sync(sg_phys(sg), sg->length, dir);
+		arc_dma_sync_single_for_cpu(dev, sg_phys(sg), sg->length, dir);
 }
 
 static void arc_dma_sync_sg_for_device(struct device *dev,
@@ -252,7 +252,8 @@ static void arc_dma_sync_sg_for_device(struct device *dev,
 	struct scatterlist *sg;
 
 	for_each_sg(sglist, sg, nelems, i)
-		_dma_cache_sync(sg_phys(sg), sg->length, dir);
+		arc_dma_sync_single_for_device(dev, sg_phys(sg), sg->length,
+				dir);
 }
 
 static int arc_dma_supported(struct device *dev, u64 dma_mask)
-- 
2.17.0

[PATCH 4/6] arc: fix arc_dma_sync_sg_for_{cpu,device}

[Christoph Hellwig]

These functions should perform the same functionality as calling
arc_dma_sync_single_for_{cpu,device} on each S/G list element.  Ensure
they actually do that by calling arc_dma_sync_single_for_{cpu,device}.
Otherwise we could be passing a different dir argument.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 arch/arc/mm/dma.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/arc/mm/dma.c b/arch/arc/mm/dma.c
index 98e21ce526be..eafdbd2ad20a 100644
--- a/arch/arc/mm/dma.c
+++ b/arch/arc/mm/dma.c
@@ -241,7 +241,7 @@ static void arc_dma_sync_sg_for_cpu(struct device *dev,
 	struct scatterlist *sg;
 
 	for_each_sg(sglist, sg, nelems, i)
-		_dma_cache_sync(sg_phys(sg), sg->length, dir);
+		arc_dma_sync_single_for_cpu(dev, sg_phys(sg), sg->length, dir);
 }
 
 static void arc_dma_sync_sg_for_device(struct device *dev,
@@ -252,7 +252,8 @@ static void arc_dma_sync_sg_for_device(struct device *dev,
 	struct scatterlist *sg;
 
 	for_each_sg(sglist, sg, nelems, i)
-		_dma_cache_sync(sg_phys(sg), sg->length, dir);
+		arc_dma_sync_single_for_device(dev, sg_phys(sg), sg->length,
+				dir);
 }
 
 static int arc_dma_supported(struct device *dev, u64 dma_mask)
-- 
2.17.0

[PATCH 5/6] arc: fix arc_dma_{map,unmap}_page

[Christoph Hellwig]

These functions should perform the same cache synchronoization as calling
arc_dma_sync_single_for_{cpu,device} in addition to doing any required
address translation or mapping [1].  Ensure they actually do that by calling
arc_dma_sync_single_for_{cpu,device} instead of passing the dir argument
along to _dma_cache_sync.

The now unused _dma_cache_sync function is removed as well.

[1] in fact various drivers rely on that by passing DMA_ATTR_SKIP_CPU_SYNC
to the map/unmap routines and doing the cache synchronization manually.

Signed-off-by: Christoph Hellwig <hch at lst.de>
---
 arch/arc/mm/dma.c | 27 ++-------------------------
 1 file changed, 2 insertions(+), 25 deletions(-)

diff --git a/arch/arc/mm/dma.c b/arch/arc/mm/dma.c
index eafdbd2ad20a..08d91c13ac52 100644
--- a/arch/arc/mm/dma.c
+++ b/arch/arc/mm/dma.c
@@ -130,29 +130,6 @@ static int arc_dma_mmap(struct device *dev, struct vm_area_struct *vma,
 	return ret;
 }
 
-/*
- * streaming DMA Mapping API...
- * CPU accesses page via normal paddr, thus needs to explicitly made
- * consistent before each use
- */
-static void _dma_cache_sync(phys_addr_t paddr, size_t size,
-		enum dma_data_direction dir)
-{
-	switch (dir) {
-	case DMA_FROM_DEVICE:
-		dma_cache_inv(paddr, size);
-		break;
-	case DMA_TO_DEVICE:
-		dma_cache_wback(paddr, size);
-		break;
-	case DMA_BIDIRECTIONAL:
-		dma_cache_wback_inv(paddr, size);
-		break;
-	default:
-		pr_err("Invalid DMA dir [%d] for OP @ %pa[p]\n", dir, &paddr);
-	}
-}
-
 static void arc_dma_sync_single_for_device(struct device *dev,
 		dma_addr_t dma_handle, size_t size, enum dma_data_direction dir)
 {
@@ -185,7 +162,7 @@ static dma_addr_t arc_dma_map_page(struct device *dev, struct page *page,
 	phys_addr_t paddr = page_to_phys(page) + offset;
 
 	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
-		_dma_cache_sync(paddr, size, dir);
+		arc_dma_sync_single_for_device(dev, paddr, size, dir);
 
 	return paddr;
 }
@@ -205,7 +182,7 @@ static void arc_dma_unmap_page(struct device *dev, dma_addr_t handle,
 	phys_addr_t paddr = handle;
 
 	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
-		_dma_cache_sync(paddr, size, dir);
+		arc_dma_sync_single_for_cpu(dev, paddr, size, dir);
 }
 
 static int arc_dma_map_sg(struct device *dev, struct scatterlist *sg,
-- 
2.17.0

[PATCH 5/6] arc: fix arc_dma_{map,unmap}_page

[Christoph Hellwig]

These functions should perform the same cache synchronoization as calling
arc_dma_sync_single_for_{cpu,device} in addition to doing any required
address translation or mapping [1].  Ensure they actually do that by calling
arc_dma_sync_single_for_{cpu,device} instead of passing the dir argument
along to _dma_cache_sync.

The now unused _dma_cache_sync function is removed as well.

[1] in fact various drivers rely on that by passing DMA_ATTR_SKIP_CPU_SYNC
to the map/unmap routines and doing the cache synchronization manually.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 arch/arc/mm/dma.c | 27 ++-------------------------
 1 file changed, 2 insertions(+), 25 deletions(-)

diff --git a/arch/arc/mm/dma.c b/arch/arc/mm/dma.c
index eafdbd2ad20a..08d91c13ac52 100644
--- a/arch/arc/mm/dma.c
+++ b/arch/arc/mm/dma.c
@@ -130,29 +130,6 @@ static int arc_dma_mmap(struct device *dev, struct vm_area_struct *vma,
 	return ret;
 }
 
-/*
- * streaming DMA Mapping API...
- * CPU accesses page via normal paddr, thus needs to explicitly made
- * consistent before each use
- */
-static void _dma_cache_sync(phys_addr_t paddr, size_t size,
-		enum dma_data_direction dir)
-{
-	switch (dir) {
-	case DMA_FROM_DEVICE:
-		dma_cache_inv(paddr, size);
-		break;
-	case DMA_TO_DEVICE:
-		dma_cache_wback(paddr, size);
-		break;
-	case DMA_BIDIRECTIONAL:
-		dma_cache_wback_inv(paddr, size);
-		break;
-	default:
-		pr_err("Invalid DMA dir [%d] for OP @ %pa[p]\n", dir, &paddr);
-	}
-}
-
 static void arc_dma_sync_single_for_device(struct device *dev,
 		dma_addr_t dma_handle, size_t size, enum dma_data_direction dir)
 {
@@ -185,7 +162,7 @@ static dma_addr_t arc_dma_map_page(struct device *dev, struct page *page,
 	phys_addr_t paddr = page_to_phys(page) + offset;
 
 	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
-		_dma_cache_sync(paddr, size, dir);
+		arc_dma_sync_single_for_device(dev, paddr, size, dir);
 
 	return paddr;
 }
@@ -205,7 +182,7 @@ static void arc_dma_unmap_page(struct device *dev, dma_addr_t handle,
 	phys_addr_t paddr = handle;
 
 	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
-		_dma_cache_sync(paddr, size, dir);
+		arc_dma_sync_single_for_cpu(dev, paddr, size, dir);
 }
 
 static int arc_dma_map_sg(struct device *dev, struct scatterlist *sg,
-- 
2.17.0

[PATCH 6/6] arc: use generic dma_noncoherent_ops

[Christoph Hellwig]

Switch to the generic noncoherent direct mapping implementation.

Signed-off-by: Christoph Hellwig <hch at lst.de>
---
 arch/arc/Kconfig                   |   4 +
 arch/arc/include/asm/Kbuild        |   1 +
 arch/arc/include/asm/dma-mapping.h |  21 -----
 arch/arc/mm/dma.c                  | 140 +++--------------------------
 4 files changed, 18 insertions(+), 148 deletions(-)
 delete mode 100644 arch/arc/include/asm/dma-mapping.h

diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig
index 7498aca4b887..89d47eac18b2 100644
--- a/arch/arc/Kconfig
+++ b/arch/arc/Kconfig
@@ -9,11 +9,15 @@
 config ARC
 	def_bool y
 	select ARC_TIMERS
+	select ARCH_HAS_SYNC_DMA_FOR_CPU
+	select ARCH_HAS_SYNC_DMA_FOR_DEVICE
 	select ARCH_HAS_SG_CHAIN
 	select ARCH_SUPPORTS_ATOMIC_RMW if ARC_HAS_LLSC
 	select BUILDTIME_EXTABLE_SORT
 	select CLONE_BACKWARDS
 	select COMMON_CLK
+	select DMA_NONCOHERENT_OPS
+	select DMA_NONCOHERENT_MMAP
 	select GENERIC_ATOMIC64 if !ISA_ARCV2 || !(ARC_HAS_LL64 && ARC_HAS_LLSC)
 	select GENERIC_CLOCKEVENTS
 	select GENERIC_FIND_FIRST_BIT
diff --git a/arch/arc/include/asm/Kbuild b/arch/arc/include/asm/Kbuild
index 4bd5d4369e05..bbdcb955e18f 100644
--- a/arch/arc/include/asm/Kbuild
+++ b/arch/arc/include/asm/Kbuild
@@ -2,6 +2,7 @@
 generic-y += bugs.h
 generic-y += device.h
 generic-y += div64.h
+generic-y += dma-mapping.h
 generic-y += emergency-restart.h
 generic-y += extable.h
 generic-y += fb.h
diff --git a/arch/arc/include/asm/dma-mapping.h b/arch/arc/include/asm/dma-mapping.h
deleted file mode 100644
index 7a16824bfe98..000000000000
--- a/arch/arc/include/asm/dma-mapping.h
+++ /dev/null
@@ -1,21 +0,0 @@
-/*
- * DMA Mapping glue for ARC
- *
- * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- */
-
-#ifndef ASM_ARC_DMA_MAPPING_H
-#define ASM_ARC_DMA_MAPPING_H
-
-extern const struct dma_map_ops arc_dma_ops;
-
-static inline const struct dma_map_ops *get_arch_dma_ops(struct bus_type *bus)
-{
-	return &arc_dma_ops;
-}
-
-#endif
diff --git a/arch/arc/mm/dma.c b/arch/arc/mm/dma.c
index 08d91c13ac52..8c1071840979 100644
--- a/arch/arc/mm/dma.c
+++ b/arch/arc/mm/dma.c
@@ -16,13 +16,12 @@
  * The default DMA address == Phy address which is 0x8000_0000 based.
  */
 
-#include <linux/dma-mapping.h>
+#include <linux/dma-noncoherent.h>
 #include <asm/cache.h>
 #include <asm/cacheflush.h>
 
-
-static void *arc_dma_alloc(struct device *dev, size_t size,
-		dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
+void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
+		gfp_t gfp, unsigned long attrs)
 {
 	unsigned long order = get_order(size);
 	struct page *page;
@@ -89,7 +88,7 @@ static void *arc_dma_alloc(struct device *dev, size_t size,
 	return kvaddr;
 }
 
-static void arc_dma_free(struct device *dev, size_t size, void *vaddr,
+void arch_dma_free(struct device *dev, size_t size, void *vaddr,
 		dma_addr_t dma_handle, unsigned long attrs)
 {
 	phys_addr_t paddr = dma_handle;
@@ -105,9 +104,9 @@ static void arc_dma_free(struct device *dev, size_t size, void *vaddr,
 	__free_pages(page, get_order(size));
 }
 
-static int arc_dma_mmap(struct device *dev, struct vm_area_struct *vma,
-			void *cpu_addr, dma_addr_t dma_addr, size_t size,
-			unsigned long attrs)
+int arch_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 user_count = vma_pages(vma);
 	unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
@@ -130,127 +129,14 @@ static int arc_dma_mmap(struct device *dev, struct vm_area_struct *vma,
 	return ret;
 }
 
-static void arc_dma_sync_single_for_device(struct device *dev,
-		dma_addr_t dma_handle, size_t size, enum dma_data_direction dir)
-{
-	dma_cache_wback(dma_handle, size);
-}
-
-static void arc_dma_sync_single_for_cpu(struct device *dev,
-		dma_addr_t dma_handle, size_t size, enum dma_data_direction dir)
-{
-	dma_cache_inv(dma_handle, size);
-}
-
-/*
- * arc_dma_map_page - map a portion of a page for streaming DMA
- *
- * Ensure that any data held in the cache is appropriately discarded
- * or written back.
- *
- * The device owns this memory once this call has completed.  The CPU
- * can regain ownership by calling dma_unmap_page().
- *
- * Note: while it takes struct page as arg, caller can "abuse" it to pass
- * a region larger than PAGE_SIZE, provided it is physically contiguous
- * and this still works correctly
- */
-static dma_addr_t arc_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 paddr = page_to_phys(page) + offset;
-
-	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
-		arc_dma_sync_single_for_device(dev, paddr, size, dir);
-
-	return paddr;
-}
-
-/*
- * arc_dma_unmap_page - unmap a buffer previously mapped through dma_map_page()
- *
- * After this call, reads by the CPU to the buffer are guaranteed to see
- * whatever the device wrote there.
- *
- * Note: historically this routine was not implemented for ARC
- */
-static void arc_dma_unmap_page(struct device *dev, dma_addr_t handle,
-			       size_t size, enum dma_data_direction dir,
-			       unsigned long attrs)
-{
-	phys_addr_t paddr = handle;
-
-	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
-		arc_dma_sync_single_for_cpu(dev, paddr, size, dir);
-}
-
-static int arc_dma_map_sg(struct device *dev, struct scatterlist *sg,
-	   int nents, enum dma_data_direction dir, unsigned long attrs)
+void arch_sync_dma_for_device(struct device *dev, phys_addr_t paddr,
+		size_t size, enum dma_data_direction dir)
 {
-	struct scatterlist *s;
-	int i;
-
-	for_each_sg(sg, s, nents, i)
-		s->dma_address = dma_map_page(dev, sg_page(s), s->offset,
-					       s->length, dir);
-
-	return nents;
+	dma_cache_wback(paddr, size);
 }
 
-static void arc_dma_unmap_sg(struct device *dev, struct scatterlist *sg,
-			     int nents, enum dma_data_direction dir,
-			     unsigned long attrs)
+void arch_sync_dma_for_cpu(struct device *dev, phys_addr_t paddr,
+		size_t size, enum dma_data_direction dir)
 {
-	struct scatterlist *s;
-	int i;
-
-	for_each_sg(sg, s, nents, i)
-		arc_dma_unmap_page(dev, sg_dma_address(s), sg_dma_len(s), dir,
-				   attrs);
+	dma_cache_inv(paddr, size);
 }
-
-static void arc_dma_sync_sg_for_cpu(struct device *dev,
-		struct scatterlist *sglist, int nelems,
-		enum dma_data_direction dir)
-{
-	int i;
-	struct scatterlist *sg;
-
-	for_each_sg(sglist, sg, nelems, i)
-		arc_dma_sync_single_for_cpu(dev, sg_phys(sg), sg->length, dir);
-}
-
-static void arc_dma_sync_sg_for_device(struct device *dev,
-		struct scatterlist *sglist, int nelems,
-		enum dma_data_direction dir)
-{
-	int i;
-	struct scatterlist *sg;
-
-	for_each_sg(sglist, sg, nelems, i)
-		arc_dma_sync_single_for_device(dev, sg_phys(sg), sg->length,
-				dir);
-}
-
-static int arc_dma_supported(struct device *dev, u64 dma_mask)
-{
-	/* Support 32 bit DMA mask exclusively */
-	return dma_mask == DMA_BIT_MASK(32);
-}
-
-const struct dma_map_ops arc_dma_ops = {
-	.alloc			= arc_dma_alloc,
-	.free			= arc_dma_free,
-	.mmap			= arc_dma_mmap,
-	.map_page		= arc_dma_map_page,
-	.unmap_page		= arc_dma_unmap_page,
-	.map_sg			= arc_dma_map_sg,
-	.unmap_sg		= arc_dma_unmap_sg,
-	.sync_single_for_device	= arc_dma_sync_single_for_device,
-	.sync_single_for_cpu	= arc_dma_sync_single_for_cpu,
-	.sync_sg_for_cpu	= arc_dma_sync_sg_for_cpu,
-	.sync_sg_for_device	= arc_dma_sync_sg_for_device,
-	.dma_supported		= arc_dma_supported,
-};
-EXPORT_SYMBOL(arc_dma_ops);
-- 
2.17.0

[PATCH 6/6] arc: use generic dma_noncoherent_ops

[Christoph Hellwig]

Switch to the generic noncoherent direct mapping implementation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 arch/arc/Kconfig                   |   4 +
 arch/arc/include/asm/Kbuild        |   1 +
 arch/arc/include/asm/dma-mapping.h |  21 -----
 arch/arc/mm/dma.c                  | 140 +++--------------------------
 4 files changed, 18 insertions(+), 148 deletions(-)
 delete mode 100644 arch/arc/include/asm/dma-mapping.h

diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig
index 7498aca4b887..89d47eac18b2 100644
--- a/arch/arc/Kconfig
+++ b/arch/arc/Kconfig
@@ -9,11 +9,15 @@
 config ARC
 	def_bool y
 	select ARC_TIMERS
+	select ARCH_HAS_SYNC_DMA_FOR_CPU
+	select ARCH_HAS_SYNC_DMA_FOR_DEVICE
 	select ARCH_HAS_SG_CHAIN
 	select ARCH_SUPPORTS_ATOMIC_RMW if ARC_HAS_LLSC
 	select BUILDTIME_EXTABLE_SORT
 	select CLONE_BACKWARDS
 	select COMMON_CLK
+	select DMA_NONCOHERENT_OPS
+	select DMA_NONCOHERENT_MMAP
 	select GENERIC_ATOMIC64 if !ISA_ARCV2 || !(ARC_HAS_LL64 && ARC_HAS_LLSC)
 	select GENERIC_CLOCKEVENTS
 	select GENERIC_FIND_FIRST_BIT
diff --git a/arch/arc/include/asm/Kbuild b/arch/arc/include/asm/Kbuild
index 4bd5d4369e05..bbdcb955e18f 100644
--- a/arch/arc/include/asm/Kbuild
+++ b/arch/arc/include/asm/Kbuild
@@ -2,6 +2,7 @@
 generic-y += bugs.h
 generic-y += device.h
 generic-y += div64.h
+generic-y += dma-mapping.h
 generic-y += emergency-restart.h
 generic-y += extable.h
 generic-y += fb.h
diff --git a/arch/arc/include/asm/dma-mapping.h b/arch/arc/include/asm/dma-mapping.h
deleted file mode 100644
index 7a16824bfe98..000000000000
--- a/arch/arc/include/asm/dma-mapping.h
+++ /dev/null
@@ -1,21 +0,0 @@
-/*
- * DMA Mapping glue for ARC
- *
- * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- */
-
-#ifndef ASM_ARC_DMA_MAPPING_H
-#define ASM_ARC_DMA_MAPPING_H
-
-extern const struct dma_map_ops arc_dma_ops;
-
-static inline const struct dma_map_ops *get_arch_dma_ops(struct bus_type *bus)
-{
-	return &arc_dma_ops;
-}
-
-#endif
diff --git a/arch/arc/mm/dma.c b/arch/arc/mm/dma.c
index 08d91c13ac52..8c1071840979 100644
--- a/arch/arc/mm/dma.c
+++ b/arch/arc/mm/dma.c
@@ -16,13 +16,12 @@
  * The default DMA address == Phy address which is 0x8000_0000 based.
  */
 
-#include <linux/dma-mapping.h>
+#include <linux/dma-noncoherent.h>
 #include <asm/cache.h>
 #include <asm/cacheflush.h>
 
-
-static void *arc_dma_alloc(struct device *dev, size_t size,
-		dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
+void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
+		gfp_t gfp, unsigned long attrs)
 {
 	unsigned long order = get_order(size);
 	struct page *page;
@@ -89,7 +88,7 @@ static void *arc_dma_alloc(struct device *dev, size_t size,
 	return kvaddr;
 }
 
-static void arc_dma_free(struct device *dev, size_t size, void *vaddr,
+void arch_dma_free(struct device *dev, size_t size, void *vaddr,
 		dma_addr_t dma_handle, unsigned long attrs)
 {
 	phys_addr_t paddr = dma_handle;
@@ -105,9 +104,9 @@ static void arc_dma_free(struct device *dev, size_t size, void *vaddr,
 	__free_pages(page, get_order(size));
 }
 
-static int arc_dma_mmap(struct device *dev, struct vm_area_struct *vma,
-			void *cpu_addr, dma_addr_t dma_addr, size_t size,
-			unsigned long attrs)
+int arch_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 user_count = vma_pages(vma);
 	unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
@@ -130,127 +129,14 @@ static int arc_dma_mmap(struct device *dev, struct vm_area_struct *vma,
 	return ret;
 }
 
-static void arc_dma_sync_single_for_device(struct device *dev,
-		dma_addr_t dma_handle, size_t size, enum dma_data_direction dir)
-{
-	dma_cache_wback(dma_handle, size);
-}
-
-static void arc_dma_sync_single_for_cpu(struct device *dev,
-		dma_addr_t dma_handle, size_t size, enum dma_data_direction dir)
-{
-	dma_cache_inv(dma_handle, size);
-}
-
-/*
- * arc_dma_map_page - map a portion of a page for streaming DMA
- *
- * Ensure that any data held in the cache is appropriately discarded
- * or written back.
- *
- * The device owns this memory once this call has completed.  The CPU
- * can regain ownership by calling dma_unmap_page().
- *
- * Note: while it takes struct page as arg, caller can "abuse" it to pass
- * a region larger than PAGE_SIZE, provided it is physically contiguous
- * and this still works correctly
- */
-static dma_addr_t arc_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 paddr = page_to_phys(page) + offset;
-
-	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
-		arc_dma_sync_single_for_device(dev, paddr, size, dir);
-
-	return paddr;
-}
-
-/*
- * arc_dma_unmap_page - unmap a buffer previously mapped through dma_map_page()
- *
- * After this call, reads by the CPU to the buffer are guaranteed to see
- * whatever the device wrote there.
- *
- * Note: historically this routine was not implemented for ARC
- */
-static void arc_dma_unmap_page(struct device *dev, dma_addr_t handle,
-			       size_t size, enum dma_data_direction dir,
-			       unsigned long attrs)
-{
-	phys_addr_t paddr = handle;
-
-	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
-		arc_dma_sync_single_for_cpu(dev, paddr, size, dir);
-}
-
-static int arc_dma_map_sg(struct device *dev, struct scatterlist *sg,
-	   int nents, enum dma_data_direction dir, unsigned long attrs)
+void arch_sync_dma_for_device(struct device *dev, phys_addr_t paddr,
+		size_t size, enum dma_data_direction dir)
 {
-	struct scatterlist *s;
-	int i;
-
-	for_each_sg(sg, s, nents, i)
-		s->dma_address = dma_map_page(dev, sg_page(s), s->offset,
-					       s->length, dir);
-
-	return nents;
+	dma_cache_wback(paddr, size);
 }
 
-static void arc_dma_unmap_sg(struct device *dev, struct scatterlist *sg,
-			     int nents, enum dma_data_direction dir,
-			     unsigned long attrs)
+void arch_sync_dma_for_cpu(struct device *dev, phys_addr_t paddr,
+		size_t size, enum dma_data_direction dir)
 {
-	struct scatterlist *s;
-	int i;
-
-	for_each_sg(sg, s, nents, i)
-		arc_dma_unmap_page(dev, sg_dma_address(s), sg_dma_len(s), dir,
-				   attrs);
+	dma_cache_inv(paddr, size);
 }
-
-static void arc_dma_sync_sg_for_cpu(struct device *dev,
-		struct scatterlist *sglist, int nelems,
-		enum dma_data_direction dir)
-{
-	int i;
-	struct scatterlist *sg;
-
-	for_each_sg(sglist, sg, nelems, i)
-		arc_dma_sync_single_for_cpu(dev, sg_phys(sg), sg->length, dir);
-}
-
-static void arc_dma_sync_sg_for_device(struct device *dev,
-		struct scatterlist *sglist, int nelems,
-		enum dma_data_direction dir)
-{
-	int i;
-	struct scatterlist *sg;
-
-	for_each_sg(sglist, sg, nelems, i)
-		arc_dma_sync_single_for_device(dev, sg_phys(sg), sg->length,
-				dir);
-}
-
-static int arc_dma_supported(struct device *dev, u64 dma_mask)
-{
-	/* Support 32 bit DMA mask exclusively */
-	return dma_mask == DMA_BIT_MASK(32);
-}
-
-const struct dma_map_ops arc_dma_ops = {
-	.alloc			= arc_dma_alloc,
-	.free			= arc_dma_free,
-	.mmap			= arc_dma_mmap,
-	.map_page		= arc_dma_map_page,
-	.unmap_page		= arc_dma_unmap_page,
-	.map_sg			= arc_dma_map_sg,
-	.unmap_sg		= arc_dma_unmap_sg,
-	.sync_single_for_device	= arc_dma_sync_single_for_device,
-	.sync_single_for_cpu	= arc_dma_sync_single_for_cpu,
-	.sync_sg_for_cpu	= arc_dma_sync_sg_for_cpu,
-	.sync_sg_for_device	= arc_dma_sync_sg_for_device,
-	.dma_supported		= arc_dma_supported,
-};
-EXPORT_SYMBOL(arc_dma_ops);
-- 
2.17.0

arc dma mapping cleanups/fixes and generic noncohernt dma code

[Alexey Brodkin]

Hi Christoph,

On Fri, 2018-05-18@15:45 +0200, Christoph Hellwig wrote:
> Hi all,
> 
> this series continues consolidating the dma-mapping code, with a focus
> on architectures that do not (always) provide cache coherence for DMA.
> Three architectures (arm, mips and powerpc) are still left to be
> converted later due to complexity of their dma ops selection.
> 
> The dma-noncoherent ops calls the dma-direct ops for the actual
> translation of streaming mappins and allow the architecture to provide
> any cache flushing required for cpu to device and/or device to cpu
> ownership transfers.  The dma coherent allocator is for now still left
> entirely to architecture supplied implementations due the amount of
> variations.  Hopefully we can do some consolidation for them later on
> as well.
> 
> Because this series sits on top of two previously submitted series
> a git tree might be useful to actually test it.  It is provided here:
> 
>     git://git.infradead.org/users/hch/misc.git arc-dma
> 
> Gitweb:
> 
>     https://urldefense.proofpoint.com/v2/url?u=http-3A__git.infradead.org_users_hch_misc.git_shortlog_refs_heads_arc-2Ddma&d=DwIBAg&c=DPL6_X_6JkXFx7
> AXWqB0tg&r=lqdeeSSEes0GFDDl656eViXO7breS55ytWkhpk5R81I&m=QNC0zOG4bRotSxdjQfFXl0dAQJCtnxtF9435wAuJlu0&s=Wad1ptsFpknoSn0ebr3_QMJn9G_D3eIS-LYMwGfOJ-
> I&e=
> 
> Changes since previous bigger series:
>  - take the offset into account in noncoherent_dma_map_page (Alexey Brodkin)
>  - fix dma directions in arc (Alexey Brodkin)
>  - split arc changes into smaller patches

I really like this series especially how it trimmed down arch/arc/mm/dma.c:
---------------------------->8----------------------------
git diff --stat HEAD~4
 arch/arc/Kconfig                   |   4 +++
 arch/arc/include/asm/Kbuild        |   1 +
 arch/arc/include/asm/dma-mapping.h |  21 ---------------
 arch/arc/mm/cache.c                |   2 +-
 arch/arc/mm/dma.c                  | 162 ++++++++++------------------------------------------------------------------------------------------------
---------
---------------------------->8----------------------------

So if we set aside my complaints about direction in arch_sync_dma_for_{device|cpu}()...

Tested-by: Alexey Brodkin <abrodkin at synopsys.com>

Let's still wait for Vineet's ack as he's the chief maintainer for ARC :)

-Alexey 

Re: arc dma mapping cleanups/fixes and generic noncohernt dma code

[Alexey Brodkin]

Hi Christoph,

On Fri, 2018-05-18 at 15:45 +0200, Christoph Hellwig wrote:
> Hi all,
> 
> this series continues consolidating the dma-mapping code, with a focus
> on architectures that do not (always) provide cache coherence for DMA.
> Three architectures (arm, mips and powerpc) are still left to be
> converted later due to complexity of their dma ops selection.
> 
> The dma-noncoherent ops calls the dma-direct ops for the actual
> translation of streaming mappins and allow the architecture to provide
> any cache flushing required for cpu to device and/or device to cpu
> ownership transfers.  The dma coherent allocator is for now still left
> entirely to architecture supplied implementations due the amount of
> variations.  Hopefully we can do some consolidation for them later on
> as well.
> 
> Because this series sits on top of two previously submitted series
> a git tree might be useful to actually test it.  It is provided here:
> 
>     git://git.infradead.org/users/hch/misc.git arc-dma
> 
> Gitweb:
> 
>     https://urldefense.proofpoint.com/v2/url?u=http-3A__git.infradead.org_users_hch_misc.git_shortlog_refs_heads_arc-2Ddma&d=DwIBAg&c=DPL6_X_6JkXFx7
> AXWqB0tg&r=lqdeeSSEes0GFDDl656eViXO7breS55ytWkhpk5R81I&m=QNC0zOG4bRotSxdjQfFXl0dAQJCtnxtF9435wAuJlu0&s=Wad1ptsFpknoSn0ebr3_QMJn9G_D3eIS-LYMwGfOJ-
> I&e=
> 
> Changes since previous bigger series:
>  - take the offset into account in noncoherent_dma_map_page (Alexey Brodkin)
>  - fix dma directions in arc (Alexey Brodkin)
>  - split arc changes into smaller patches

I really like this series especially how it trimmed down arch/arc/mm/dma.c:
---------------------------->8----------------------------
git diff --stat HEAD~4
 arch/arc/Kconfig                   |   4 +++
 arch/arc/include/asm/Kbuild        |   1 +
 arch/arc/include/asm/dma-mapping.h |  21 ---------------
 arch/arc/mm/cache.c                |   2 +-
 arch/arc/mm/dma.c                  | 162 ++++++++++------------------------------------------------------------------------------------------------
---------
---------------------------->8----------------------------

So if we set aside my complaints about direction in arch_sync_dma_for_{device|cpu}()...

Tested-by: Alexey Brodkin <abrodkin-HKixBCOQz3hWk0Htik3J/w@public.gmane.org>

Let's still wait for Vineet's ack as he's the chief maintainer for ARC :)

-Alexey 

arc dma mapping cleanups/fixes and generic noncohernt dma code

[hch]

On Fri, May 18, 2018@02:49:36PM +0000, Alexey Brodkin wrote:
> So if we set aside my complaints about direction in arch_sync_dma_for_{device|cpu}()...

Many other architectures use the argument.  Various of those look bogus,
but for now I want to be able to do straight forward conversions.  If
we end up not needing the argument in the end we can still remove it
eventually.

Re: arc dma mapping cleanups/fixes and generic noncohernt dma code

[hch-jcswGhMUV9g]

On Fri, May 18, 2018 at 02:49:36PM +0000, Alexey Brodkin wrote:
> So if we set aside my complaints about direction in arch_sync_dma_for_{device|cpu}()...

Many other architectures use the argument.  Various of those look bogus,
but for now I want to be able to do straight forward conversions.  If
we end up not needing the argument in the end we can still remove it
eventually.

arc dma mapping cleanups/fixes and generic noncohernt dma code

[Vineet Gupta]

On 05/18/2018 06:45 AM, Christoph Hellwig wrote:
> Hi all,
>
> this series continues consolidating the dma-mapping code, with a focus
> on architectures that do not (always) provide cache coherence for DMA.
> Three architectures (arm, mips and powerpc) are still left to be
> converted later due to complexity of their dma ops selection.
>
> The dma-noncoherent ops calls the dma-direct ops for the actual
> translation of streaming mappins and allow the architecture to provide
> any cache flushing required for cpu to device and/or device to cpu
> ownership transfers.  The dma coherent allocator is for now still left
> entirely to architecture supplied implementations due the amount of
> variations.  Hopefully we can do some consolidation for them later on
> as well.
>
> Because this series sits on top of two previously submitted series
> a git tree might be useful to actually test it.  It is provided here:
>
>      git://git.infradead.org/users/hch/misc.git arc-dma
>
> Gitweb:
>
>      https://urldefense.proofpoint.com/v2/url?u=http-3A__git.infradead.org_users_hch_misc.git_shortlog_refs_heads_arc-2Ddma&d=DwIBAg&c=DPL6_X_6JkXFx7AXWqB0tg&r=7FgpX6o3vAhwMrMhLh-4ZJey5kjdNUwOL2CWsFwR4T8&m=9mEjcnTLzOrHy9MqruvxfxgCZQ1c0Bs4EQ8F7G-F4M8&s=TV7HWlNcSsk79JReNvLa5u1vsIkJxrk_s6RsL5CMNW4&e=
>
> Changes since previous bigger series:
>   - take the offset into account in noncoherent_dma_map_page (Alexey Brodkin)
>   - fix dma directions in arc (Alexey Brodkin)
>   - split arc changes into smaller patches
>

LGTM !

Acked-by: Vineet Gupta <vgupta at synopsys.com>

Thx,
-Vineet

Re: arc dma mapping cleanups/fixes and generic noncohernt dma code

[Vineet Gupta]

On 05/18/2018 06:45 AM, Christoph Hellwig wrote:
> Hi all,
>
> this series continues consolidating the dma-mapping code, with a focus
> on architectures that do not (always) provide cache coherence for DMA.
> Three architectures (arm, mips and powerpc) are still left to be
> converted later due to complexity of their dma ops selection.
>
> The dma-noncoherent ops calls the dma-direct ops for the actual
> translation of streaming mappins and allow the architecture to provide
> any cache flushing required for cpu to device and/or device to cpu
> ownership transfers.  The dma coherent allocator is for now still left
> entirely to architecture supplied implementations due the amount of
> variations.  Hopefully we can do some consolidation for them later on
> as well.
>
> Because this series sits on top of two previously submitted series
> a git tree might be useful to actually test it.  It is provided here:
>
>      git://git.infradead.org/users/hch/misc.git arc-dma
>
> Gitweb:
>
>      https://urldefense.proofpoint.com/v2/url?u=http-3A__git.infradead.org_users_hch_misc.git_shortlog_refs_heads_arc-2Ddma&d=DwIBAg&c=DPL6_X_6JkXFx7AXWqB0tg&r=7FgpX6o3vAhwMrMhLh-4ZJey5kjdNUwOL2CWsFwR4T8&m=9mEjcnTLzOrHy9MqruvxfxgCZQ1c0Bs4EQ8F7G-F4M8&s=TV7HWlNcSsk79JReNvLa5u1vsIkJxrk_s6RsL5CMNW4&e=
>
> Changes since previous bigger series:
>   - take the offset into account in noncoherent_dma_map_page (Alexey Brodkin)
>   - fix dma directions in arc (Alexey Brodkin)
>   - split arc changes into smaller patches
>

LGTM !

Acked-by: Vineet Gupta <vgupta-HKixBCOQz3hWk0Htik3J/w@public.gmane.org>

Thx,
-Vineet