dma-mapping: move the remap helpers to a separate file

The dma remap code only makes sense for not cache coherent architectures
(or possibly the corner case of highmem CMA allocations) and currently
is only used by arm, arm64, csky and xtensa.  Split it out into a
separate file with a separate Kconfig symbol, which gets the right
copyright notice given that this code was written by Laura Abbott
working for Code Aurora at that point.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Laura Abbott <labbott@redhat.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 91be74d..3b2852d 100644 (file)
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -30,6 +30,7 @@ config ARM
        select CPU_PM if (SUSPEND || CPU_IDLE)
        select DCACHE_WORD_ACCESS if HAVE_EFFICIENT_UNALIGNED_ACCESS
        select DMA_DIRECT_OPS if !MMU
+       select DMA_REMAP if MMU
        select EDAC_SUPPORT
        select EDAC_ATOMIC_SCRUB
        select GENERIC_ALLOCATOR

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 787d785..5d065ac 100644 (file)
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -82,6 +82,7 @@ config ARM64
        select CRC32
        select DCACHE_WORD_ACCESS
        select DMA_DIRECT_OPS
+       select DMA_REMAP
        select EDAC_SUPPORT
        select FRAME_POINTER
        select GENERIC_ALLOCATOR

diff --git a/arch/csky/Kconfig b/arch/csky/Kconfig
index cb64f8d..8a30e00 100644 (file)
--- a/arch/csky/Kconfig
+++ b/arch/csky/Kconfig
@@ -9,6 +9,7 @@ config CSKY
        select CLKSRC_OF
        select DMA_DIRECT_OPS
        select DMA_NONCOHERENT_OPS
+       select DMA_REMAP
        select IRQ_DOMAIN
        select HANDLE_DOMAIN_IRQ
        select DW_APB_TIMER_OF

diff --git a/arch/xtensa/Kconfig b/arch/xtensa/Kconfig
index d29b736..239bfb1 100644 (file)
--- a/arch/xtensa/Kconfig
+++ b/arch/xtensa/Kconfig
@@ -11,6 +11,7 @@ config XTENSA
        select CLONE_BACKWARDS
        select COMMON_CLK
        select DMA_DIRECT_OPS
+       select DMA_REMAP if MMU
        select GENERIC_ATOMIC64
        select GENERIC_CLOCKEVENTS
        select GENERIC_IRQ_SHOW

diff --git a/kernel/dma/Kconfig b/kernel/dma/Kconfig
index 645c7a2..c92e081 100644 (file)
--- a/kernel/dma/Kconfig
+++ b/kernel/dma/Kconfig
@@ -51,3 +51,7 @@ config SWIOTLB
        bool
        select DMA_DIRECT_OPS
        select NEED_DMA_MAP_STATE
+
+config DMA_REMAP
+       depends on MMU
+       bool

diff --git a/kernel/dma/Makefile b/kernel/dma/Makefile
index 7d581e4..f4feece 100644 (file)
--- a/kernel/dma/Makefile
+++ b/kernel/dma/Makefile
@@ -7,4 +7,4 @@ obj-$(CONFIG_DMA_DIRECT_OPS)            += direct.o
 obj-$(CONFIG_DMA_VIRT_OPS)             += virt.o
 obj-$(CONFIG_DMA_API_DEBUG)            += debug.o
 obj-$(CONFIG_SWIOTLB)                  += swiotlb.o
-
+obj-$(CONFIG_DMA_REMAP)                        += remap.o

diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
index 58dec7a..dfbc3de 100644 (file)
--- a/kernel/dma/mapping.c
+++ b/kernel/dma/mapping.c
@@ -262,87 +262,3 @@ int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
 #endif /* !CONFIG_ARCH_NO_COHERENT_DMA_MMAP */
 }
 EXPORT_SYMBOL(dma_common_mmap);
-
-#ifdef CONFIG_MMU
-static struct vm_struct *__dma_common_pages_remap(struct page **pages,
-                       size_t size, unsigned long vm_flags, pgprot_t prot,
-                       const void *caller)
-{
-       struct vm_struct *area;
-
-       area = get_vm_area_caller(size, vm_flags, caller);
-       if (!area)
-               return NULL;
-
-       if (map_vm_area(area, prot, pages)) {
-               vunmap(area->addr);
-               return NULL;
-       }
-
-       return area;
-}
-
-/*
- * remaps an array of PAGE_SIZE pages into another vm_area
- * Cannot be used in non-sleeping contexts
- */
-void *dma_common_pages_remap(struct page **pages, size_t size,
-                       unsigned long vm_flags, pgprot_t prot,
-                       const void *caller)
-{
-       struct vm_struct *area;
-
-       area = __dma_common_pages_remap(pages, size, vm_flags, prot, caller);
-       if (!area)
-               return NULL;
-
-       area->pages = pages;
-
-       return area->addr;
-}
-
-/*
- * remaps an allocated contiguous region into another vm_area.
- * Cannot be used in non-sleeping contexts
- */
-
-void *dma_common_contiguous_remap(struct page *page, size_t size,
-                       unsigned long vm_flags,
-                       pgprot_t prot, const void *caller)
-{
-       int i;
-       struct page **pages;
-       struct vm_struct *area;
-
-       pages = kmalloc(sizeof(struct page *) << get_order(size), GFP_KERNEL);
-       if (!pages)
-               return NULL;
-
-       for (i = 0; i < (size >> PAGE_SHIFT); i++)
-               pages[i] = nth_page(page, i);
-
-       area = __dma_common_pages_remap(pages, size, vm_flags, prot, caller);
-
-       kfree(pages);
-
-       if (!area)
-               return NULL;
-       return area->addr;
-}
-
-/*
- * unmaps a range previously mapped by dma_common_*_remap
- */
-void dma_common_free_remap(void *cpu_addr, size_t size, unsigned long vm_flags)
-{
-       struct vm_struct *area = find_vm_area(cpu_addr);
-
-       if (!area || (area->flags & vm_flags) != vm_flags) {
-               WARN(1, "trying to free invalid coherent area: %p\n", cpu_addr);
-               return;
-       }
-
-       unmap_kernel_range((unsigned long)cpu_addr, PAGE_ALIGN(size));
-       vunmap(cpu_addr);
-}
-#endif

diff --git a/kernel/dma/remap.c b/kernel/dma/remap.c
new file mode 100644 (file)
index 0000000..a15c393
--- /dev/null
+++ b/kernel/dma/remap.c
@@ -0,0 +1,88 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2014 The Linux Foundation
+ */
+#include <linux/dma-mapping.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+
+static struct vm_struct *__dma_common_pages_remap(struct page **pages,
+                       size_t size, unsigned long vm_flags, pgprot_t prot,
+                       const void *caller)
+{
+       struct vm_struct *area;
+
+       area = get_vm_area_caller(size, vm_flags, caller);
+       if (!area)
+               return NULL;
+
+       if (map_vm_area(area, prot, pages)) {
+               vunmap(area->addr);
+               return NULL;
+       }
+
+       return area;
+}
+
+/*
+ * Remaps an array of PAGE_SIZE pages into another vm_area.
+ * Cannot be used in non-sleeping contexts
+ */
+void *dma_common_pages_remap(struct page **pages, size_t size,
+                       unsigned long vm_flags, pgprot_t prot,
+                       const void *caller)
+{
+       struct vm_struct *area;
+
+       area = __dma_common_pages_remap(pages, size, vm_flags, prot, caller);
+       if (!area)
+               return NULL;
+
+       area->pages = pages;
+
+       return area->addr;
+}
+
+/*
+ * Remaps an allocated contiguous region into another vm_area.
+ * Cannot be used in non-sleeping contexts
+ */
+void *dma_common_contiguous_remap(struct page *page, size_t size,
+                       unsigned long vm_flags,
+                       pgprot_t prot, const void *caller)
+{
+       int i;
+       struct page **pages;
+       struct vm_struct *area;
+
+       pages = kmalloc(sizeof(struct page *) << get_order(size), GFP_KERNEL);
+       if (!pages)
+               return NULL;
+
+       for (i = 0; i < (size >> PAGE_SHIFT); i++)
+               pages[i] = nth_page(page, i);
+
+       area = __dma_common_pages_remap(pages, size, vm_flags, prot, caller);
+
+       kfree(pages);
+
+       if (!area)
+               return NULL;
+       return area->addr;
+}
+
+/*
+ * Unmaps a range previously mapped by dma_common_*_remap
+ */
+void dma_common_free_remap(void *cpu_addr, size_t size, unsigned long vm_flags)
+{
+       struct vm_struct *area = find_vm_area(cpu_addr);
+
+       if (!area || (area->flags & vm_flags) != vm_flags) {
+               WARN(1, "trying to free invalid coherent area: %p\n", cpu_addr);
+               return;
+       }
+
+       unmap_kernel_range((unsigned long)cpu_addr, PAGE_ALIGN(size));
+       vunmap(cpu_addr);
+}