The amdgpu_dm_plane.h functions didn't have names that indicated where
they were declared.

To better filter results in debug tools like ftrace, prefix these
functions with 'amdgpu_dm_plane_'.

Note that we may want to make this same change in other files like
amdgpu_dm_crtc.h.

Signed-off-by: David Tadokoro <davidbtadokoro@usp.br>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

[Why]
We only allowed 1 overlay plane. But now some ASICS can support multiple
overlay planes.

[How]
Use max_slave_planes as the number of overlays we can support.

Also since we cannot draw cursor over a video plane, we need to make
sure that we reject commits where the topmost plane is a video plane
(overlay only).

Reviewed-by: Nicholas Kazlauskas <Nicholas.Kazlauskas@amd.com>
Acked-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

The file amdgpu_dm_plane.c missed the header amdgpu_dm_plane.h, which
resulted on the following warning:

drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm_plane.c:1046:5:
warning: no previous prototype for 'fill_dc_scaling_info'
[-Wmissing-prototypes]
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm_plane.c:1222:6:
warning: no previous prototype for 'handle_cursor_update'
[-Wmissing-prototypes]
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm_plane.c:152:6:
warning: no previous prototype for 'modifier_has_dcc'
[-Wmissing-prototypes]
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm_plane.c:1576:5:
warning: no previous prototype for 'amdgpu_dm_plane_init'
[-Wmissing-prototypes]
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm_plane.c:157:10:
warning: no previous prototype for 'modifier_gfx9_swizzle_mode'
[-Wmissing-prototypes]
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm_plane.c:752:5:
warning: no previous prototype for 'fill_plane_buffer_attributes'
[-Wmissing-prototypes]
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm_plane.c:83:31:
warning: no previous prototype for 'amd_get_format_info'
[-Wmissing-prototypes]
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm_plane.c:88:6:
warning: no previous prototype for 'fill_blending_from_plane_state'
[-Wmissing-prototypes]
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm_plane.c:992:5:
warning: no previous prototype for 'dm_plane_helper_check_state'
[-Wmissing-prototypes]

Therefore, include the missing header on the file and turn global functions
that are not used outside of the file into static functions.

Fixes: 5d945cbcd4b1 ("drm/amd/display: Create a file dedicated to planes")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Maíra Canal <mairacanal@riseup.net>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

[Why]
The amdgpu_dm file contains most of the code that works as an interface
between DRM API and DC. As a result, this file becomes very large since
it comprises multiple abstractions such as plane manipulation.

[How]
This commit extracts the plane code to its specific file named
amdgpu_dm_plane. This change does not change anything inside the
functions; the only exception is converting some static functions to a
global function.

Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Reviewed-by: Harry Wentland <Harry.Wentland@amd.com>
Acked-by: Alan Liu <HaoPing.Liu@amd.com>
Signed-off-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>