drm/i915/d12+: Disable DMC firmware flip queue handlers

Based on a bspec update the DMC firmware's flip queue handling events
need to be disabled before enabling DC5/6. i915 doesn't use the flip
queue feature atm, so disable it already after loading the firmware.
This removes some overhead of the event handler which runs at a 1 kHz
frequency.

Bspec: 49193, 72486, 72487

v2:
- Fix the DMC pipe A register offsets for GEN12.
- Disable the events on DG2 only on pipe A..D .
v3: (Lucas)
- Add TODO: to clarify the disabling sequence on all D13+
- s/intel_dmc_has_fw_payload/has_dmc_id_fw/
- s/simple_flipq/flipq/
- s/_GEN12,_GEN13/TGL_,ADLP_/
- s/MAINDMC/DMC/
v4:
- Only disable flip queues on TGL/DG2, as on other platforms the
  corresponding event handlers don't exist.

Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Anusha Srivatsa <anusha.srivatsa@intel.com> # v1
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220521130808.637449-1-imre.deak@intel.com

2 files changed, 133 insertions, 1 deletions

diff --git a/drivers/gpu/drm/i915/display/intel_dmc.c b/drivers/gpu/drm/i915/display/intel_dmc.c
index 34d00f5aff25..fa9ef591b885 100644
--- a/drivers/gpu/drm/i915/display/intel_dmc.c
+++ b/drivers/gpu/drm/i915/display/intel_dmc.c
@@ -248,9 +248,14 @@ struct stepping_info {
 	char substepping;
 };
 
+static bool has_dmc_id_fw(struct drm_i915_private *i915, int dmc_id)
+{
+	return i915->dmc.dmc_info[dmc_id].payload;
+}
+
 bool intel_dmc_has_payload(struct drm_i915_private *i915)
 {
-	return i915->dmc.dmc_info[DMC_FW_MAIN].payload;
+	return has_dmc_id_fw(i915, DMC_FW_MAIN);
 }
 
 static const struct stepping_info *
@@ -272,6 +277,85 @@ 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_flip_queue_event(struct drm_i915_private *i915,
+			 i915_reg_t ctl_reg, i915_reg_t htp_reg)
+{
+	u32 event_ctl;
+	u32 event_htp;
+
+	event_ctl = intel_de_read(i915, ctl_reg);
+	event_htp = intel_de_read(i915, htp_reg);
+	if (event_ctl != (DMC_EVT_CTL_ENABLE |
+			  DMC_EVT_CTL_RECURRING |
+			  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_CLK_MSEC)) ||
+	    !event_htp) {
+		drm_dbg_kms(&i915->drm,
+			    "Unexpected DMC event configuration (control %08x htp %08x)\n",
+			    event_ctl, event_htp);
+		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);
+}
+
+static bool
+get_flip_queue_event_regs(struct drm_i915_private *i915, int dmc_id,
+			  i915_reg_t *ctl_reg, i915_reg_t *htp_reg)
+{
+	switch (dmc_id) {
+	case DMC_FW_MAIN:
+		if (DISPLAY_VER(i915) == 12) {
+			*ctl_reg = DMC_EVT_CTL(i915, dmc_id, 3);
+			*htp_reg = DMC_EVT_HTP(i915, dmc_id, 3);
+
+			return true;
+		}
+		break;
+	case DMC_FW_PIPEA ... DMC_FW_PIPED:
+		if (IS_DG2(i915)) {
+			*ctl_reg = DMC_EVT_CTL(i915, dmc_id, 2);
+			*htp_reg = DMC_EVT_HTP(i915, dmc_id, 2);
+
+			return true;
+		}
+		break;
+	}
+
+	return false;
+}
+
+static void
+disable_all_flip_queue_events(struct drm_i915_private *i915)
+{
+	int dmc_id;
+
+	/* TODO: check if the following applies to all D13+ platforms. */
+	if (!IS_DG2(i915) && !IS_TIGERLAKE(i915))
+		return;
+
+	for (dmc_id = 0; dmc_id < DMC_FW_MAX; dmc_id++) {
+		i915_reg_t ctl_reg;
+		i915_reg_t htp_reg;
+
+		if (!has_dmc_id_fw(i915, dmc_id))
+			continue;
+
+		if (!get_flip_queue_event_regs(i915, dmc_id, &ctl_reg, &htp_reg))
+			continue;
+
+		disable_flip_queue_event(i915, ctl_reg, htp_reg);
+	}
+}
+
 /**
  * intel_dmc_load_program() - write the firmware from memory to register.
  * @dev_priv: i915 drm device.
@@ -312,6 +396,13 @@ void intel_dmc_load_program(struct drm_i915_private *dev_priv)
 	dev_priv->dmc.dc_state = 0;
 
 	gen9_set_dc_state_debugmask(dev_priv);
+
+	/*
+	 * Flip queue events need to be disabled before enabling DC5/6.
+	 * i915 doesn't use the flip queue feature, so disable it already
+	 * here.
+	 */
+	disable_all_flip_queue_events(dev_priv);
 }
 
 void assert_dmc_loaded(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 67e14eb96a7a..238620b55966 100644
--- a/drivers/gpu/drm/i915/display/intel_dmc_regs.h
+++ b/drivers/gpu/drm/i915/display/intel_dmc_regs.h
@@ -10,6 +10,47 @@
 
 #define DMC_PROGRAM(addr, i)	_MMIO((addr) + (i) * 4)
 #define DMC_SSP_BASE_ADDR_GEN9	0x00002FC0
+
+#define _ADLP_PIPEDMC_REG_MMIO_BASE_A	0x5f000
+#define _TGL_PIPEDMC_REG_MMIO_BASE_A	0x92000
+
+#define __PIPEDMC_REG_MMIO_BASE(i915, dmc_id) \
+	((DISPLAY_VER(i915) >= 13 ? _ADLP_PIPEDMC_REG_MMIO_BASE_A : \
+				    _TGL_PIPEDMC_REG_MMIO_BASE_A) + \
+	 0x400 * ((dmc_id) - 1))
+
+#define __DMC_REG_MMIO_BASE		0x8f000
+
+#define _DMC_REG_MMIO_BASE(i915, dmc_id) \
+	((dmc_id) == DMC_FW_MAIN ? __DMC_REG_MMIO_BASE : \
+				   __PIPEDMC_REG_MMIO_BASE(i915, dmc_id))
+
+#define _DMC_REG(i915, dmc_id, reg) \
+	((reg) - __DMC_REG_MMIO_BASE + _DMC_REG_MMIO_BASE(i915, dmc_id))
+
+#define _DMC_EVT_HTP_0			0x8f004
+
+#define DMC_EVT_HTP(i915, dmc_id, handler) \
+	_MMIO(_DMC_REG(i915, dmc_id, _DMC_EVT_HTP_0) + 4 * (handler))
+
+#define _DMC_EVT_CTL_0			0x8f034
+
+#define DMC_EVT_CTL(i915, dmc_id, handler) \
+	_MMIO(_DMC_REG(i915, dmc_id, _DMC_EVT_CTL_0) + 4 * (handler))
+
+#define DMC_EVT_CTL_ENABLE		REG_BIT(31)
+#define DMC_EVT_CTL_RECURRING		REG_BIT(30)
+#define DMC_EVT_CTL_TYPE_MASK		REG_GENMASK(17, 16)
+#define DMC_EVT_CTL_TYPE_LEVEL_0	0
+#define DMC_EVT_CTL_TYPE_LEVEL_1	1
+#define DMC_EVT_CTL_TYPE_EDGE_1_0	2
+#define DMC_EVT_CTL_TYPE_EDGE_0_1	3
+
+#define DMC_EVT_CTL_EVENT_ID_MASK	REG_GENMASK(15, 8)
+#define DMC_EVT_CTL_EVENT_ID_FALSE	0x01
+/* An event handler scheduled to run at a 1 kHz frequency. */
+#define DMC_EVT_CTL_EVENT_ID_CLK_MSEC	0xbf
+
 #define DMC_HTP_ADDR_SKL	0x00500034
 #define DMC_SSP_BASE		_MMIO(0x8F074)
 #define DMC_HTP_SKL		_MMIO(0x8F004)