drm/amd: Introduce additional IPS debug flags

[Why]

Idle power states (IPS) describe levels of power-gating within DCN. DM
and DC is responsible for ensuring that we are out of IPS before any DCN
programming happens. Any DCN programming while we're in IPS leads to
undefined behavior (mostly hangs).

Because IPS intersects with all display features, the ability to disable
IPS by default while ironing out the known issues is desired. However,
disabing it completely will cause important features such as s0ix entry
to fail.

Therefore, more granular IPS debug flags are desired.

[How]

Extend the dc debug mask bits to include the available list of IPS
debug flags.

All the flags should work as documented, with the exception of
IPS_DISABLE_DYNAMIC. It requires dm changes which will be done in
later changes.

v2: enable docs and fix docstring format

Signed-off-by: Leo Li <[e-mail]>
Reviewed-by: Aurabindo Pillai <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

Documentation/gpu/amdgpu/driver-core.rst

···
    :doc: IP Blocks
 
 .. kernel-doc:: drivers/gpu/drm/amd/include/amd_shared.h
-   :identifiers: amd_ip_block_type amd_ip_funcs
+   :identifiers: amd_ip_block_type amd_ip_funcs DC_DEBUG_MASK

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

···
 
 	if (amdgpu_dc_debug_mask & DC_DISABLE_IPS)
 		init_data.flags.disable_ips = DMUB_IPS_DISABLE_ALL;
+	else if (amdgpu_dc_debug_mask & DC_DISABLE_IPS_DYNAMIC)
+		init_data.flags.disable_ips = DMUB_IPS_DISABLE_DYNAMIC;
+	else if (amdgpu_dc_debug_mask & DC_DISABLE_IPS2_DYNAMIC)
+		init_data.flags.disable_ips = DMUB_IPS_RCG_IN_ACTIVE_IPS2_IN_OFF;
+	else if (amdgpu_dc_debug_mask & DC_FORCE_IPS_ENABLE)
+		init_data.flags.disable_ips = DMUB_IPS_ENABLE;
 	else
 		init_data.flags.disable_ips = DMUB_IPS_ENABLE;
 

drivers/gpu/drm/amd/include/amd_shared.h

···
 * acquires the list of IP blocks for the GPU in use on initialization.
 * It can then operate on this list to perform standard driver operations
 * such as: init, fini, suspend, resume, etc.
-* 
+*
 *
 * IP block implementations are named using the following convention:
 * <functionality>_v<version> (E.g.: gfx_v6_0).
···
 	DC_REPLAY_MASK = (1 << 9), //0x200, disabled by default for dcn < 3.1.4
 };
 
+/**
+ * enum DC_DEBUG_MASK - Bits that are useful for debugging the Display Core IP
+ */
 enum DC_DEBUG_MASK {
+	/**
+	 * @DC_DISABLE_PIPE_SPLIT: If set, disable pipe-splitting
+	 */
 	DC_DISABLE_PIPE_SPLIT = 0x1,
+
+	/**
+	 * @DC_DISABLE_STUTTER: If set, disable memory stutter mode
+	 */
 	DC_DISABLE_STUTTER = 0x2,
+
+	/**
+	 * @DC_DISABLE_DSC: If set, disable display stream compression
+	 */
 	DC_DISABLE_DSC = 0x4,
+
+	/**
+	 * @DC_DISABLE_CLOCK_GATING: If set, disable clock gating optimizations
+	 */
 	DC_DISABLE_CLOCK_GATING = 0x8,
+
+	/**
+	 * @DC_DISABLE_PSR: If set, disable Panel self refresh v1 and PSR-SU
+	 */
 	DC_DISABLE_PSR = 0x10,
+
+	/**
+	 * @DC_FORCE_SUBVP_MCLK_SWITCH: If set, force mclk switch in subvp, even
+	 * if mclk switch in vblank is possible
+	 */
 	DC_FORCE_SUBVP_MCLK_SWITCH = 0x20,
+
+	/**
+	 * @DC_DISABLE_MPO: If set, disable multi-plane offloading
+	 */
 	DC_DISABLE_MPO = 0x40,
+
+	/**
+	 * @DC_ENABLE_DPIA_TRACE: If set, enable trace logging for DPIA
+	 */
 	DC_ENABLE_DPIA_TRACE = 0x80,
+
+	/**
+	 * @DC_ENABLE_DML2: If set, force usage of DML2, even if the DCN version
+	 * does not default to it.
+	 */
 	DC_ENABLE_DML2 = 0x100,
+
+	/**
+	 * @DC_DISABLE_PSR_SU: If set, disable PSR SU
+	 */
 	DC_DISABLE_PSR_SU = 0x200,
+
+	/**
+	 * @DC_DISABLE_REPLAY: If set, disable Panel Replay
+	 */
 	DC_DISABLE_REPLAY = 0x400,
+
+	/**
+	 * @DC_DISABLE_IPS: If set, disable all Idle Power States, all the time.
+	 * If more than one IPS debug bit is set, the lowest bit takes
+	 * precedence. For example, if DC_FORCE_IPS_ENABLE and
+	 * DC_DISABLE_IPS_DYNAMIC are set, then DC_DISABLE_IPS_DYNAMIC takes
+	 * precedence.
+	 */
 	DC_DISABLE_IPS = 0x800,
+
+	/**
+	 * @DC_DISABLE_IPS_DYNAMIC: If set, disable all IPS, all the time,
+	 * *except* when driver goes into suspend.
+	 */
+	DC_DISABLE_IPS_DYNAMIC = 0x1000,
+
+	/**
+	 * @DC_DISABLE_IPS2_DYNAMIC: If set, disable IPS2 (IPS1 allowed) if
+	 * there is an enabled display. Otherwise, enable all IPS.
+	 */
+	DC_DISABLE_IPS2_DYNAMIC = 0x2000,
+
+	/**
+	 * @DC_FORCE_IPS_ENABLE: If set, force enable all IPS, all the time.
+	 */
+	DC_FORCE_IPS_ENABLE = 0x4000,
 };
 
 enum amd_dpm_forced_level;