[PATCH 6.12.y 7/8] drm/i915/lobf: Add mutex for alpm update

[Sasha Levin <sashal@kernel.org>]

From: Animesh Manna <animesh.manna@intel.com>

[ Upstream commit acff6d6bded31d98698693827860adc5befdd854 ]

The ALPM_CTL can be updated from different context, so
add mutex to sychonize the update.

Signed-off-by: Animesh Manna <animesh.manna@intel.com>
Reviewed-by: Jouni Högander <jouni.hogander@intel.com>
Link: https://lore.kernel.org/r/20250423092334.2294483-9-animesh.manna@intel.com
Stable-dep-of: eb4a7139e973 ("drm/i915/alpm: ALPM disable fixes")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/i915/display/intel_alpm.c          | 11 ++++++++++-
 drivers/gpu/drm/i915/display/intel_alpm.h          |  2 +-
 drivers/gpu/drm/i915/display/intel_display_types.h |  1 +
 drivers/gpu/drm/i915/display/intel_dp.c            |  2 +-
 4 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_alpm.c b/drivers/gpu/drm/i915/display/intel_alpm.c
index e3004725e044b..d72e10160f1d4 100644
--- a/drivers/gpu/drm/i915/display/intel_alpm.c
+++ b/drivers/gpu/drm/i915/display/intel_alpm.c
@@ -21,7 +21,7 @@ bool intel_alpm_aux_less_wake_supported(struct intel_dp *intel_dp)
 	return intel_dp->alpm_dpcd & DP_ALPM_AUX_LESS_CAP;
 }
 
-void intel_alpm_init_dpcd(struct intel_dp *intel_dp)
+void intel_alpm_init(struct intel_dp *intel_dp)
 {
 	u8 dpcd;
 
@@ -29,6 +29,7 @@ void intel_alpm_init_dpcd(struct intel_dp *intel_dp)
 		return;
 
 	intel_dp->alpm_dpcd = dpcd;
+	mutex_init(&intel_dp->alpm_parameters.lock);
 }
 
 /*
@@ -318,6 +319,7 @@ static void lnl_alpm_configure(struct intel_dp *intel_dp,
 	    (!intel_dp->psr.sel_update_enabled && !intel_dp_is_edp(intel_dp)))
 		return;
 
+	mutex_lock(&intel_dp->alpm_parameters.lock);
 	/*
 	 * Panel Replay on eDP is always using ALPM aux less. I.e. no need to
 	 * check panel support at this point.
@@ -357,6 +359,7 @@ static void lnl_alpm_configure(struct intel_dp *intel_dp,
 	alpm_ctl |= ALPM_CTL_ALPM_ENTRY_CHECK(intel_dp->alpm_parameters.check_entry_lines);
 
 	intel_de_write(display, ALPM_CTL(display, cpu_transcoder), alpm_ctl);
+	mutex_unlock(&intel_dp->alpm_parameters.lock);
 }
 
 void intel_alpm_configure(struct intel_dp *intel_dp,
@@ -396,8 +399,10 @@ void intel_alpm_pre_plane_update(struct intel_atomic_state *state,
 			continue;
 
 		if (old_crtc_state->has_lobf) {
+			mutex_lock(&intel_dp->alpm_parameters.lock);
 			intel_de_write(display, ALPM_CTL(display, cpu_transcoder), 0);
 			drm_dbg_kms(display->drm, "Link off between frames (LOBF) disabled\n");
+			mutex_unlock(&intel_dp->alpm_parameters.lock);
 		}
 	}
 }
@@ -487,6 +492,8 @@ void intel_alpm_disable(struct intel_dp *intel_dp)
 	if (DISPLAY_VER(display) < 20)
 		return;
 
+	mutex_lock(&intel_dp->alpm_parameters.lock);
+
 	intel_de_rmw(display, ALPM_CTL(display, cpu_transcoder),
 		     ALPM_CTL_ALPM_ENABLE | ALPM_CTL_LOBF_ENABLE |
 		     ALPM_CTL_ALPM_AUX_LESS_ENABLE, 0);
@@ -494,4 +501,6 @@ void intel_alpm_disable(struct intel_dp *intel_dp)
 	intel_de_rmw(display,
 		     PORT_ALPM_CTL(cpu_transcoder),
 		     PORT_ALPM_CTL_ALPM_AUX_LESS_ENABLE, 0);
+
+	mutex_unlock(&intel_dp->alpm_parameters.lock);
 }
diff --git a/drivers/gpu/drm/i915/display/intel_alpm.h b/drivers/gpu/drm/i915/display/intel_alpm.h
index 77bae022a0eaf..c043a071f84f3 100644
--- a/drivers/gpu/drm/i915/display/intel_alpm.h
+++ b/drivers/gpu/drm/i915/display/intel_alpm.h
@@ -15,7 +15,7 @@ struct intel_connector;
 struct intel_atomic_state;
 struct intel_crtc;
 
-void intel_alpm_init_dpcd(struct intel_dp *intel_dp);
+void intel_alpm_init(struct intel_dp *intel_dp);
 bool intel_alpm_compute_params(struct intel_dp *intel_dp,
 			       const struct intel_crtc_state *crtc_state);
 void intel_alpm_lobf_compute_config(struct intel_dp *intel_dp,
diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
index b6a388f5a7c8b..cb4b192c9e9bd 100644
--- a/drivers/gpu/drm/i915/display/intel_display_types.h
+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
@@ -1907,6 +1907,7 @@ struct intel_dp {
 		u8 io_wake_lines;
 		u8 fast_wake_lines;
 		enum transcoder transcoder;
+		struct mutex lock;
 
 		/* LNL and beyond */
 		u8 check_entry_lines;
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index eb4952be7bccc..fd9d9649c962d 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -6716,7 +6716,7 @@ static bool intel_edp_init_connector(struct intel_dp *intel_dp,
 	 */
 	intel_hpd_enable_detection(encoder);
 
-	intel_alpm_init_dpcd(intel_dp);
+	intel_alpm_init(intel_dp);
 
 	/* Cache DPCD and EDID for edp. */
 	has_dpcd = intel_edp_init_dpcd(intel_dp, intel_connector);
-- 
2.51.0