Re: [PATCH 3/9] dma-mapping: move the remap helpers to a separate file
From: Robin Murphy
Date: Fri Nov 30 2018 - 14:05:12 EST
On 05/11/2018 12:19, Christoph Hellwig wrote:
The dma remap code only really makes sense for not cache coherent
architectures,
And coherent ones with highmem, presumably? That can at least be the
case on 32-bit Arm, where coherent LPAE systems do exist (e.g. Calxeda
Midway).
and currently is only used by arm, arm64 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.
Ignoring the further super-nitpick that the comments got subtle grammar
fixes in some places but not others,
Reviewed-by: Robin Murphy <robin.murphy@xxxxxxx>
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Acked-by: Laura Abbott <labbott@xxxxxxxxxx>
---
arch/arm/Kconfig | 1 +
arch/arm64/Kconfig | 1 +
arch/csky/Kconfig | 1 +
arch/xtensa/Kconfig | 1 +
kernel/dma/Kconfig | 4 ++
kernel/dma/Makefile | 2 +-
kernel/dma/mapping.c | 84 ------------------------------------------
kernel/dma/remap.c | 88 ++++++++++++++++++++++++++++++++++++++++++++
8 files changed, 97 insertions(+), 85 deletions(-)
create mode 100644 kernel/dma/remap.c
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 91be74d8df65..3b2852df6eb3 100644
--- 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 787d7850e064..5d065acb6d10 100644
--- 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 cb64f8dacd08..8a30e006a845 100644
--- 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 d29b7365da8d..239bfb16c58b 100644
--- 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 645c7a2ecde8..c92e08173ed8 100644
--- 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 7d581e4eea4a..f4feeceb8020 100644
--- 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 58dec7a92b7b..dfbc3deb95cd 100644
--- 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
index 000000000000..456f7cc3414d
--- /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);
+}