drm/amdgpu: fix SI failure due to doorbells allocation

SI hardware does not have doorbells at all, however currently the code
will try to do the allocation and thus fail, makes SI AMDGPU not usable.

Fix this failure by skipping doorbells allocation when doorbells count
is zero.

Fixes: 54c30d2a8def ("drm/amdgpu: create kernel doorbell pages")
Reviewed-by: Shashank Sharma <shashank.sharma@amd.com>
Signed-off-by: Icenowy Zheng <uwu@icenowy.me>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drm/amdkfd: get doorbell's absolute offset based on the db_size

Here, Adding db_size in byte to find the doorbell's
absolute offset for both 32-bit and 64-bit doorbell sizes.
So that doorbell offset will be aligned based on the doorbell
size.

v2:
- Addressed the review comment from Felix.
v3:
- Adding doorbell_size as parameter to get db absolute offset.
v4:
Squash the two patches into one.

Cc: Christian Koenig <christian.koenig@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Shashank Sharma <shashank.sharma@amd.com>
Signed-off-by: Arvind Yadav <Arvind.Yadav@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drm/amd/amdgpu/amdgpu_doorbell_mgr: Correct misdocumented param 'doorbell_index'

Fixes the following W=1 kernel build warning(s):

drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell_mgr.c:123: warning: Function parameter or member 'doorbell_index' not described in 'amdgpu_doorbell_index_on_bar'
drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell_mgr.c:123: warning: Excess function parameter 'db_index' description in 'amdgpu_doorbell_index_on_bar'

Reviewed-by: Shashank Sharma <shashank.sharma@amd.com>
Signed-off-by: Lee Jones <lee@kernel.org>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drm/amdgpu: fix SI failure due to doorbells allocation

SI hardware does not have doorbells at all, however currently the code
will try to do the allocation and thus fail, makes SI AMDGPU not usable.

Fix this failure by skipping doorbells allocation when doorbells count
is zero.

Fixes: 54c30d2a8def ("drm/amdgpu: create kernel doorbell pages")
Reviewed-by: Shashank Sharma <shashank.sharma@amd.com>
Signed-off-by: Icenowy Zheng <uwu@icenowy.me>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drm/amdgpu: use doorbell mgr for MES kernel doorbells

This patch:
- Removes the existing doorbell management code, and its variables
from the doorbell_init function, it will be done in doorbell
manager now.
- uses the doorbell page created for MES kernel level needs (doorbells
for MES self tests)
- current MES code was allocating MES doorbells in MES process context,
but those were getting written using kernel doorbell calls. This patch
instead allocates a MES kernel doorbell for this (in add_hw_queue).

V2: Create an extra page of doorbells for MES during kernel doorbell
creation (Alex)
V4: Move MES doorbell size and page offset objects in this patch from
patch 6.

Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Christian Koenig <christian.koenig@amd.com>
Reviewed-by: Christian Koenig <christian.koenig@amd.com>
Signed-off-by: Shashank Sharma <shashank.sharma@amd.com>
Signed-off-by: Arvind Yadav <arvind.yadav@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drm/amdgpu: get absolute offset from doorbell index

This patch adds a helper function which converts a doorbell's
relative index in a BO to an absolute doorbell offset in the
doorbell BAR.

V2: No space between the variable name doc (Luben)

Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Christian Koenig <christian.koenig@amd.com>
Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Shashank Sharma <shashank.sharma@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drm/amdgpu: create kernel doorbell pages

This patch:
- creates a doorbell page for graphics driver usages.
- adds a few new varlables in adev->doorbell structure to
keep track of kernel's doorbell-bo.
- removes the adev->doorbell.ptr variable, replaces it with
kernel-doorbell-bo's cpu address.

V2: - Create doorbell BO directly, no wrappe functions (Alex)
- no additional doorbell structure (Alex, Christian)
- Use doorbell_cpu_ptr, remove ioremap (Christian, Alex)
- Allocate one extra page of doorbells for MES (Alex)

V4: Move MES doorbell base init into MES related patch (Christian)

Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Christian Koenig <christian.koenig@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Shashank Sharma <shashank.sharma@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drm/amdgpu: don't modify num_doorbells for mes

This patch removes the check and change in num_kernel_doorbells
for MES, which is not being used anywhere by MES code.

V2: Fixed checkpatch warnings.

Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Christian Koenig <christian.koenig@amd.com>
Reviewed-by: Christian Koenig <christian.koenig@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Shashank Sharma <shashank.sharma@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drm/amdgpu: create a new file for doorbell manager

This patch:
- creates a new file for doorbell management.
- moves doorbell code from amdgpu_device.c to this file.

V2:
- remove doc from function declaration (Christian)
- remove 'device' from function names to make it consistent (Alex)
- add SPDX license identifier (Luben)

V3:
- change license to MIT license(Christian)

Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Christian Koenig <christian.koenig@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Shashank Sharma <shashank.sharma@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>