Add support to permit mapping memory with protection infoHEADmaster

The standard galcore user memory mapping function fails when asked to
map read-only memory, such as X shmem buffers.  The reason these fail
is because get_user_pages() is always attempted with "write" mode
enabled, which is not permissible with read-only mappings.

To allow this to work (so that Xv can be implemented efficiently) we
must be able to map read-only buffers.  This adds an extension to
etnaviv, found in my Dove galcore driver and Jon Nettleton's iMX6
kernels which permit this without changing the existing galcore APIs.

Signed-off-by: Russell King <rmk@arm.linux.org.uk>

1 files changed, 5 insertions, 0 deletions

diff --git a/src/etnaviv/viv.h b/src/etnaviv/viv.h
index ec044f5..4496840 100644
--- a/src/etnaviv/viv.h
+++ b/src/etnaviv/viv.h
@@ -268,6 +268,11 @@ int viv_free_contiguous(struct viv_conn *conn, size_t bytes, viv_addr_t physical
  */
 int viv_map_dmabuf(struct viv_conn *conn, int fd, viv_usermem_t *info, viv_addr_t *address, int prot);
 
+/** Map user memory to GPU memory, allowing for read/write protections.
+ * Note: GPU is not protected against reads/writes.
+ */
+int viv_map_user_memory_prot(struct viv_conn *conn, void *memory, size_t size, int prot, viv_usermem_t *info, viv_addr_t *address);
+
 /** Map user memory to GPU memory.
  */
 int viv_map_user_memory(struct viv_conn *conn, void *memory, size_t size, viv_usermem_t *info, viv_addr_t *address);