gpu: nvgpu: Add elcg/blcg/slcg enabled checks

-Power features should be enabled only if s/w flags xxcg_enabled
 are set for corresponding features. These flags control whether
 feature should be kept disabled in the hardware or not. For disable
 case, register programming will happen for CG registers
 and they will be set to disabled. For ELPG, init command will be
 sent to PMU, but “ELPG_ALLOW” will not be sent to PMU.
 Also these flags can be modified using sysfs. These flags
 are noop if corresponding can_xxxg flags are set to flase.
 S/w flags can_xxxg tell the ability of platform to support
 a power feature and cannot be modified by syfs. Setting these
 flags to false will avoid any HW register write or init sequence
 for the power feature from executing. For ELPG, no commands will
 be sent to PMU.

-g->elcg_enabled flag should not be modified here.
 It should be modified only by sysfs. This will be cleaned up in
 follow up implementation where debug session will have some kind
 of lock where it will keep power features disabled as long as it
 wants to. Debugger cannot rely on this flag to keep power
 management disabled as these flags can be changed from sysfs.
 Due to this issue someone can easily break debugging session
 by accidentally changing something in sysfs.
 Proper fix for this is being tracked in NVGPU-320

Bug 1982434

Change-Id: I660ef02491f4df9910bf4dea3561ac8a0838e1b1
Signed-off-by: Deepak Goyal <dgoyal@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/1587205
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

0 files changed, 0 insertions, 0 deletions