[Bug 108920] [AMDGPU][TAHITI XT] linux unable to boot since rc3 rebase

[sylvain.bertrand at gmail.com]

Bisected:

due to many compilation errors, git say any of the following commit could be
the culprit:
663480d4e1460943de83ef14e86b8d2b0776edc6
971dbfb07e6ab4c5113898df25f39815c867a49c
103fcde3210ae17101bc1c64a78d074d61cf5cf7
85d5f3312d67bf8def41110447d19de3a0665754
0bf89d5dd1ee497df340ce932f0726d499cf9316

Seems the new doorbell support code has a broken SI(TAHITI XT) code path:

commit 663480d4e1460943de83ef14e86b8d2b0776edc6
Author: Oak Zeng <ozeng at amd.com>
Date:   Mon Nov 19 09:51:20 2018 -0600

    drm/amdgpu: Doorbell index initialization for ASICs before vega10
    
    Initialize doorbell index for asics vi and cik
    
    v2: Use enum definition instead of hardcoded number
    
    Change-Id: Id64eb98f5b1c24b51eb2fd5a083086fc3515813d
    Signed-off-by: Oak Zeng <ozeng at amd.com>
    Suggested-by: Felix Kuehling <Felix.Kuehling at amd.com>
    Suggested-by: Alex Deucher <alexander.deucher at amd.com>
    Reviewed-by: Alex Deucher <alexander.deucher at amd.com>


commit 971dbfb07e6ab4c5113898df25f39815c867a49c
Author: Oak Zeng <ozeng at amd.com>
Date:   Mon Nov 19 15:59:53 2018 -0600

    drm/amdgpu: Doorbell layout for vega20 and future asic
    
    This introduces new doorbell layout for vega20 and future asics
    
    v2: Use enum definition instead of hardcoded value
    
    Change-Id: I04d22fb717ac50483c0835f160a2e860e344f358
    Signed-off-by: Oak Zeng <ozeng at amd.com>
    Suggested-by: Felix Kuehling <Felix.Kuehling at amd.com>
    Suggested-by: Alex Deucher <alexander.deucher at amd.com>
    Reviewed-by: Alex Deucher <alexander.deucher at amd.com>


commit 103fcde3210ae17101bc1c64a78d074d61cf5cf7
Author: Oak Zeng <ozeng at amd.com>
Date:   Mon Nov 19 09:25:37 2018 -0600

    drm/amdgpu: Vega10 doorbell index initialization
    
    v2: Use enum definition instead of hardcoded value
    v3: Remove unused enum definition
    
    Change-Id: Ib72058337f0aa53adfc6c6aae5341a7cd665111a
    Signed-off-by: Oak Zeng <ozeng at amd.com>
    Suggested-by: Felix Kuehling <Felix.Kuehling at amd.com>
    Suggested-by: Alex Deucher <alexander.deucher at amd.com>
    Reviewed-by: Alex Deucher <alexander.deucher at amd.com>


commit 85d5f3312d67bf8def41110447d19de3a0665754
Author: Oak Zeng <ozeng at amd.com>
Date:   Mon Nov 19 14:36:09 2018 -0600

    drm/amdgpu: Call doorbell index init on device initialization
    
    Also call functioin amdgpu_device_doorbell_init after
    amdgpu_device_ip_early_init because the former depends
    on the later to set up asic-specific init_doorbell_index
    function
    
    Change-Id: I2f004bbbe2565035460686f4fc16e86b77a2a9b5
    Signed-off-by: Oak Zeng <ozeng at amd.com>
    Suggested-by: Felix Kuehling <Felix.Kuehling at amd.com>
    Suggested-by: Alex Deucher <alexander.deucher at amd.com>
    Reviewed-by: Alex Deucher <alexander.deucher at amd.com>


commit 0bf89d5dd1ee497df340ce932f0726d499cf9316
Author: Oak Zeng <ozeng at amd.com>
Date:   Mon Nov 19 15:20:07 2018 -0600

    drm/amdgpu: Use asic specific doorbell index instead of macro definition
    
    ASIC specific doorbell layout is used instead of enum definition
    
    Change-Id: Iffff84475efcfb482c474fccb133010abb5df5f4
    Signed-off-by: Oak Zeng <ozeng at amd.com>
    Suggested-by: Felix Kuehling <Felix.Kuehling at amd.com>
    Suggested-by: Alex Deucher <alexander.deucher at amd.com>
    Reviewed-by: Alex Deucher <alexander.deucher at amd.com>