Alex Frid efcd608f80 gpu: nvgpu: Change GM20B post-divider in flight ...

Restored changing GM20B GPCPLL post-divider in flight with the
following limitation: post divider transition is glitch-less only if
there is common "1" in binary representation of old and new settings.

Transitions that may create glitch are implemented in glitch-less steps
with minimum possible interim divider value (for example, 1 <=> 2
transition has interim value 3: 1 <=> 3 <=> 2).

Steps allowed for glitch-less transitions may not always have frequency
jump at/below VCO min/2 (in the example above 1st step jumps 2/3 of
VCOmin). Enabled external linear divider at 1:2 during such steps.

Used extra write of the same data when changing GM20b linear divider.

Bug 1552225

Change-Id: Ie8fba2fbe44afd34ca68f5f355bd302b7426a632
Signed-off-by: Alex Frid <afrid@nvidia.com>
Reviewed-on: http://git-master/r/496319
(cherry picked from commit bdd21e0003032fe664bd20f163dbab9942fd1d1d)
Reviewed-on: http://git-master/r/499193
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit
Reviewed-by: Yu-Huan Hsu <yhsu@nvidia.com>

2015-03-18 12:11:16 -07:00

..

nvgpu

gpu: nvgpu: Change GM20B post-divider in flight

2015-03-18 12:11:16 -07:00