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Diffstat (limited to 'drivers/uio/uio.c')
-rw-r--r--drivers/uio/uio.c47
1 files changed, 47 insertions, 0 deletions
diff --git a/drivers/uio/uio.c b/drivers/uio/uio.c
index 2d572f6c8e..009158fef2 100644
--- a/drivers/uio/uio.c
+++ b/drivers/uio/uio.c
@@ -24,6 +24,7 @@
#include <linux/kobject.h>
#include <linux/cdev.h>
#include <linux/uio_driver.h>
+#include <linux/dma-mapping.h>
#define UIO_MAX_DEVICES (1U << MINORBITS)
@@ -759,6 +760,49 @@ static int uio_mmap_physical(struct vm_area_struct *vma)
vma->vm_page_prot);
}
+static int uio_mmap_dma_coherent(struct vm_area_struct *vma)
+{
+ struct uio_device *idev = vma->vm_private_data;
+ struct uio_mem *mem;
+ void *addr;
+ int ret = 0;
+ int mi;
+
+ mi = uio_find_mem_index(vma);
+ if (mi < 0)
+ return -EINVAL;
+
+ mem = idev->info->mem + mi;
+
+ if (mem->addr & ~PAGE_MASK)
+ return -ENODEV;
+ if (mem->dma_addr & ~PAGE_MASK)
+ return -ENODEV;
+ if (!mem->dma_device)
+ return -ENODEV;
+ if (vma->vm_end - vma->vm_start > mem->size)
+ return -EINVAL;
+
+ dev_warn(mem->dma_device,
+ "use of UIO_MEM_DMA_COHERENT is highly discouraged");
+
+ /*
+ * UIO uses offset to index into the maps for a device.
+ * We need to clear vm_pgoff for dma_mmap_coherent.
+ */
+ vma->vm_pgoff = 0;
+
+ addr = (void *)(uintptr_t)mem->addr;
+ ret = dma_mmap_coherent(mem->dma_device,
+ vma,
+ addr,
+ mem->dma_addr,
+ vma->vm_end - vma->vm_start);
+ vma->vm_pgoff = mi;
+
+ return ret;
+}
+
static int uio_mmap(struct file *filep, struct vm_area_struct *vma)
{
struct uio_listener *listener = filep->private_data;
@@ -806,6 +850,9 @@ static int uio_mmap(struct file *filep, struct vm_area_struct *vma)
case UIO_MEM_VIRTUAL:
ret = uio_mmap_logical(vma);
break;
+ case UIO_MEM_DMA_COHERENT:
+ ret = uio_mmap_dma_coherent(vma);
+ break;
default:
ret = -EINVAL;
}