gpu: nvgpu: Add __nvgpu_mem_create_from_pages()

Add a function to create a nvgpu_mem from a list of arbitrary pages.
This API is useful for pages not necessarily allocated by the Linux
page allocator. It is useful for making nvgpu_mems that represent
carveouts or other things like that.

JIRA NVGPU-12
JIRA NVGPU-30

Change-Id: Ibcb6432f077a6b0ecf9d183248e47a1f9ecb3ddd
Signed-off-by: Alex Waterman <alexw@nvidia.com>
Reviewed-on: http://git-master/r/1464080
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>
Reviewed-by: svccoveritychecker <svccoveritychecker@nvidia.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/drivers/gpu/nvgpu/include/nvgpu/nvgpu_mem.h b/drivers/gpu/nvgpu/include/nvgpu/nvgpu_mem.h
index b01fbec5..66d04ab8 100644
--- a/drivers/gpu/nvgpu/include/nvgpu/nvgpu_mem.h
+++ b/drivers/gpu/nvgpu/include/nvgpu/nvgpu_mem.h
@@ -68,6 +68,16 @@ struct nvgpu_mem {
          * therefor zeroed (to prevent leaking information in VIDMEM buffers).
          */
 #define NVGPU_MEM_FLAG_USER_MEM                  (1 << 2)
+
+        /*
+         * Internal flag that specifies this struct has not been made with DMA
+         * memory and as a result should not try to use the DMA routines for
+         * freeing the backing memory.
+         *
+         * However, this will not stop the DMA API from freeing other parts of
+         * nvgpu_mem in a system specific way.
+         */
+#define __NVGPU_MEM_FLAG_NO_DMA                  (1 << 3)
         unsigned long                            mem_flags;
 
         /*