gpu: nvgpu: move submit path to linux

Nvgpu submit path has a lot of dependency on Linux framework
e.g. use of copy_from_user, use of structures defined in uapi/nvgpu headers,
dma_buf_* calls for trace support etc

Hence to keep common code independent of Linux code, move submit path to
Linux directory

Move below APIs to common/linux/channel.c
trace_write_pushbuffer()
trace_write_pushbuffer_range()
gk20a_submit_prepare_syncs()
gk20a_submit_append_priv_cmdbuf()
gk20a_submit_append_gpfifo()
gk20a_submit_channel_gpfifo()

Move below APIs to common/linux/ce2.c
gk20a_ce_execute_ops()

Define gk20a_ce_execute_ops() in common/linux/ce2.c, and declare it in
gk20a/ce2_gk20a.h since it is needed in common/mm code too
Each OS needs to implement this API separately

gk20a_channel_alloc_gpfifo() use sizeof(nvgpu_gpfifo) to get size of one gpfifo
entry, but structure nvgpu_gpfifo is linux specific
Define new nvgpu_get_gpfifo_entry_size() in linux specific code and use it
in gk20a_channel_alloc_gpfifo() to get gpfifo entry size
Each OS needs to implement this API separately

Export some APIs from gk20a/ce2_gk20a.h and gk20a/channel_gk20a.h that are
needed in linux code

Jira NVGPU-259
Jira NVGPU-313

Change-Id: I360c6cb8ce4494b1e50c66af334a2a379f0d2dc4
Signed-off-by: Deepak Nibade <dnibade@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/1586277
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

drivers/gpu/nvgpu/common/linux/ioctl_channel.c

@@ -36,6 +36,7 @@
 #include "gk20a/platform_gk20a.h"
 
 #include "ioctl_channel.h"
+#include "channel.h"
 #include "os_linux.h"
 #include "ctxsw_trace.h"