gpu: nvgpu: API to access fb memory

Add IOCTL API NVGPU_DBG_GPU_IOCTL_ACCESS_FB_MEMORY
to read/write fb/vidmem memory

Interface will accept dmabuf_fd of the buffer in vidmem,
offset into the buffer to access, temporary buffer
to copy data across API, size of read/write and
command indicating either read or write operation

API will first parse all the inputs, and then call
gk20a_vidbuf_access_memory() to complete fb access

gk20a_vidbuf_access_memory() will then just use
gk20a_mem_rd_n() or gk20a_mem_wr_n() depending
on the command issued

Bug 1804714
Jira DNVGPU-192

Change-Id: Iba3c42410abe12c2884d3b603fa33d27782e4c56
Signed-off-by: Deepak Nibade <dnibade@nvidia.com>
Reviewed-on: http://git-master/r/1255556
(cherry picked from commit 2c49a8a79d93fc526adbf6f808484fa9a3fa2498)
Reviewed-on: http://git-master/r/1260471
GVS: Gerrit_Virtual_Submit
Reviewed-by: Bharat Nihalani <bnihalani@nvidia.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/mm_gk20a.h b/drivers/gpu/nvgpu/gk20a/mm_gk20a.h
index 512d32e9..36ba6248 100644
--- a/drivers/gpu/nvgpu/gk20a/mm_gk20a.h
+++ b/drivers/gpu/nvgpu/gk20a/mm_gk20a.h
@@ -762,6 +762,8 @@ void gk20a_vm_mapping_batch_finish_locked(
 
 int gk20a_vidmem_buf_alloc(struct gk20a *g, size_t bytes);
 int gk20a_vidmem_get_space(struct gk20a *g, u64 *space);
+int gk20a_vidbuf_access_memory(struct gk20a *g, struct dma_buf *dmabuf,
+                void *buffer, u64 offset, u64 size, u32 cmd);
 
 /* Note: batch may be NULL if map op is not part of a batch */
 int gk20a_vm_map_buffer(struct vm_gk20a *vm,