uio: introduce UIO_MEM_DMA_COHERENT type

[linux-2.6-block.git] / drivers / uio / uio.c

diff --git a/drivers/uio/uio.c b/drivers/uio/uio.c
index 2d572f6c8ec833023450136e3e2278d46d8937ae..bb77de6fa067efe26280b24b0f62b54ba75bcbca 100644 (file)
--- 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 *)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;
        }