[Intel-gfx] [PATCH v2 1/2] drm/i915/d12+: Disable DMC handlers during loading/disabling the firmware

[Imre Deak]

Disable the DMC event handlers before loading the firmware and after
uninitializing the display, to make sure the firmware is inactive. This
matches the Bspec "Sequences for Display C5 and C6" page for GEN12+.

Add a TODO comment for doing the same on pre-GEN12 platforms.

v2:
- Add a macro for the number of event handlers.
- Disable the event handlers only on GEN12+.
- s/dev_priv/i915/ in docbook comment.

Signed-off-by: Imre Deak <imre.deak at intel.com>
---
 .../drm/i915/display/intel_display_power.c    |  3 +
 drivers/gpu/drm/i915/display/intel_dmc.c      | 56 +++++++++++++++++--
 drivers/gpu/drm/i915/display/intel_dmc.h      |  1 +
 drivers/gpu/drm/i915/display/intel_dmc_regs.h |  2 +
 4 files changed, 56 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_display_power.c b/drivers/gpu/drm/i915/display/intel_display_power.c
index 589af257edebc..22f65a9968c6a 100644
--- a/drivers/gpu/drm/i915/display/intel_display_power.c
+++ b/drivers/gpu/drm/i915/display/intel_display_power.c
@@ -1433,6 +1433,7 @@ static void skl_display_core_uninit(struct drm_i915_private *dev_priv)
 		return;
 
 	gen9_disable_dc_states(dev_priv);
+	/* TODO: disable DMC program */
 
 	gen9_dbuf_disable(dev_priv);
 
@@ -1500,6 +1501,7 @@ static void bxt_display_core_uninit(struct drm_i915_private *dev_priv)
 		return;
 
 	gen9_disable_dc_states(dev_priv);
+	/* TODO: disable DMC program */
 
 	gen9_dbuf_disable(dev_priv);
 
@@ -1675,6 +1677,7 @@ static void icl_display_core_uninit(struct drm_i915_private *dev_priv)
 		return;
 
 	gen9_disable_dc_states(dev_priv);
+	intel_dmc_disable_program(dev_priv);
 
 	/* 1. Disable all display engine functions -> aready done */
 
diff --git a/drivers/gpu/drm/i915/display/intel_dmc.c b/drivers/gpu/drm/i915/display/intel_dmc.c
index fa9ef591b8853..f73205d1f3164 100644
--- a/drivers/gpu/drm/i915/display/intel_dmc.c
+++ b/drivers/gpu/drm/i915/display/intel_dmc.c
@@ -277,6 +277,17 @@ static void gen9_set_dc_state_debugmask(struct drm_i915_private *dev_priv)
 	intel_de_posting_read(dev_priv, DC_STATE_DEBUG);
 }
 
+static void disable_event_handler(struct drm_i915_private *i915,
+				  i915_reg_t ctl_reg, i915_reg_t htp_reg)
+{
+	intel_de_write(i915, ctl_reg,
+		       REG_FIELD_PREP(DMC_EVT_CTL_TYPE_MASK,
+				      DMC_EVT_CTL_TYPE_EDGE_0_1) |
+		       REG_FIELD_PREP(DMC_EVT_CTL_EVENT_ID_MASK,
+				      DMC_EVT_CTL_EVENT_ID_FALSE));
+	intel_de_write(i915, htp_reg, 0);
+}
+
 static void
 disable_flip_queue_event(struct drm_i915_private *i915,
 			 i915_reg_t ctl_reg, i915_reg_t htp_reg)
@@ -299,12 +310,7 @@ disable_flip_queue_event(struct drm_i915_private *i915,
 		return;
 	}
 
-	intel_de_write(i915, ctl_reg,
-		       REG_FIELD_PREP(DMC_EVT_CTL_TYPE_MASK,
-				      DMC_EVT_CTL_TYPE_EDGE_0_1) |
-		       REG_FIELD_PREP(DMC_EVT_CTL_EVENT_ID_MASK,
-				      DMC_EVT_CTL_EVENT_ID_FALSE));
-	intel_de_write(i915, htp_reg, 0);
+	disable_event_handler(i915, ctl_reg, htp_reg);
 }
 
 static bool
@@ -356,6 +362,27 @@ disable_all_flip_queue_events(struct drm_i915_private *i915)
 	}
 }
 
+static void disable_all_event_handlers(struct drm_i915_private *i915)
+{
+	int id;
+
+	/* TODO: disable the event handlers on pre-GEN12 platforms as well */
+	if (DISPLAY_VER(i915) < 12)
+		return;
+
+	for (id = DMC_FW_MAIN; id < DMC_FW_MAX; id++) {
+		int handler;
+
+		if (!has_dmc_id_fw(i915, id))
+			continue;
+
+		for (handler = 0; handler < DMC_EVENT_HANDLER_COUNT_GEN12; handler++)
+			disable_event_handler(i915,
+					      DMC_EVT_CTL(i915, id, handler),
+					      DMC_EVT_HTP(i915, id, handler));
+	}
+}
+
 /**
  * intel_dmc_load_program() - write the firmware from memory to register.
  * @dev_priv: i915 drm device.
@@ -372,6 +399,8 @@ void intel_dmc_load_program(struct drm_i915_private *dev_priv)
 	if (!intel_dmc_has_payload(dev_priv))
 		return;
 
+	disable_all_event_handlers(dev_priv);
+
 	assert_rpm_wakelock_held(&dev_priv->runtime_pm);
 
 	preempt_disable();
@@ -405,6 +434,21 @@ void intel_dmc_load_program(struct drm_i915_private *dev_priv)
 	disable_all_flip_queue_events(dev_priv);
 }
 
+/**
+ * intel_dmc_disable_program() - disable the firmware
+ * @i915: i915 drm device
+ *
+ * Disable all event handlers in the firmware, making sure the firmware is
+ * inactive after the display is uninitialized.
+ */
+void intel_dmc_disable_program(struct drm_i915_private *i915)
+{
+	if (!intel_dmc_has_payload(i915))
+		return;
+
+	disable_all_event_handlers(i915);
+}
+
 void assert_dmc_loaded(struct drm_i915_private *i915)
 {
 	drm_WARN_ONCE(&i915->drm,
diff --git a/drivers/gpu/drm/i915/display/intel_dmc.h b/drivers/gpu/drm/i915/display/intel_dmc.h
index 41091aee3b47b..67e03315ef999 100644
--- a/drivers/gpu/drm/i915/display/intel_dmc.h
+++ b/drivers/gpu/drm/i915/display/intel_dmc.h
@@ -47,6 +47,7 @@ struct intel_dmc {
 
 void intel_dmc_ucode_init(struct drm_i915_private *i915);
 void intel_dmc_load_program(struct drm_i915_private *i915);
+void intel_dmc_disable_program(struct drm_i915_private *i915);
 void intel_dmc_ucode_fini(struct drm_i915_private *i915);
 void intel_dmc_ucode_suspend(struct drm_i915_private *i915);
 void intel_dmc_ucode_resume(struct drm_i915_private *i915);
diff --git a/drivers/gpu/drm/i915/display/intel_dmc_regs.h b/drivers/gpu/drm/i915/display/intel_dmc_regs.h
index 238620b559662..5e5e41644ddfd 100644
--- a/drivers/gpu/drm/i915/display/intel_dmc_regs.h
+++ b/drivers/gpu/drm/i915/display/intel_dmc_regs.h
@@ -28,6 +28,8 @@
 #define _DMC_REG(i915, dmc_id, reg) \
 	((reg) - __DMC_REG_MMIO_BASE + _DMC_REG_MMIO_BASE(i915, dmc_id))
 
+#define DMC_EVENT_HANDLER_COUNT_GEN12	8
+
 #define _DMC_EVT_HTP_0			0x8f004
 
 #define DMC_EVT_HTP(i915, dmc_id, handler) \
-- 
2.34.1