diff mbox

[01/16] dma-mapping: make the generic coherent dma mmap implementation optional

Message ID 1447093041-21832-2-git-send-email-hch@lst.de (mailing list archive)
State Awaiting Upstream
Headers show

Commit Message

Christoph Hellwig Nov. 9, 2015, 6:17 p.m. UTC 
We have a couple architectures that do not want to support this code,
so add another Kconfig symbol that disables the code similar to what we
do for the nommu case.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 arch/Kconfig               | 3 +++
 drivers/base/dma-mapping.c | 4 ++--
 2 files changed, 5 insertions(+), 2 deletions(-)
diff mbox

Patch

diff --git a/arch/Kconfig b/arch/Kconfig
index 4e949e5..e47995f 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -564,4 +564,7 @@  config OLD_SIGACTION
 config COMPAT_OLD_SIGACTION
 	bool
 
+config ARCH_NO_COHERENT_DMA_MMAP
+	bool
+
 source "kernel/gcov/Kconfig"
diff --git a/drivers/base/dma-mapping.c b/drivers/base/dma-mapping.c
index d95c597..381e39d 100644
--- a/drivers/base/dma-mapping.c
+++ b/drivers/base/dma-mapping.c
@@ -247,7 +247,7 @@  int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
 		    void *cpu_addr, dma_addr_t dma_addr, size_t size)
 {
 	int ret = -ENXIO;
-#ifdef CONFIG_MMU
+#if defined(CONFIG_MMU) && !defined(CONFIG_ARCH_NO_COHERENT_DMA_MMAP)
 	unsigned long user_count = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
 	unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
 	unsigned long pfn = page_to_pfn(virt_to_page(cpu_addr));
@@ -264,7 +264,7 @@  int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
 				      user_count << PAGE_SHIFT,
 				      vma->vm_page_prot);
 	}
-#endif	/* CONFIG_MMU */
+#endif	/* CONFIG_MMU && !CONFIG_ARCH_NO_COHERENT_DMA_MMAP */
 
 	return ret;
 }