[Intel-gfx] [PATCH 1/7] drm/i915/perf: Ensure observation logic is not clock gated

[Umesh Nerlige Ramappa]

From: Piotr Maciejewski <piotr.maciejewski at intel.com>

A clock gating switch can control if the performance monitoring and
observation logic is enaled or not. Ensure that we enable the clocks.

v2: Separate code from other patches (Lionel)
v3: Reset PMON enable when disabling perf to save power (Lionel)
v4: Use intel_uncore_rmw and REG_BIT (Chris)

Fixes: 00a7f0d7155c ("drm/i915/tgl: Add perf support on TGL")
Signed-off-by: Piotr Maciejewski <piotr.maciejewski at intel.com>
Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa at intel.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
---
 drivers/gpu/drm/i915/i915_perf.c | 9 +++++++++
 drivers/gpu/drm/i915/i915_reg.h  | 2 ++
 2 files changed, 11 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c
index e94976976571..df5166d89d82 100644
--- a/drivers/gpu/drm/i915/i915_perf.c
+++ b/drivers/gpu/drm/i915/i915_perf.c
@@ -2520,6 +2520,12 @@ gen12_enable_metric_set(struct i915_perf_stream *stream,
 			    (period_exponent << GEN12_OAG_OAGLBCTXCTRL_TIMER_PERIOD_SHIFT))
 			    : 0);
 
+	/*
+	 * Initialize Super Queue Internal Cnt Register
+	 * Set PMON Enable in order to collect valid metrics.
+	 */
+	intel_uncore_rmw(uncore, GEN12_SQCNT1, 0, GEN12_SQCNT1_PMON_ENABLE);
+
 	/*
 	 * Update all contexts prior writing the mux configurations as we need
 	 * to make sure all slices/subslices are ON before writing to NOA
@@ -2579,6 +2585,9 @@ static void gen12_disable_metric_set(struct i915_perf_stream *stream)
 
 	/* Make sure we disable noa to save power. */
 	intel_uncore_rmw(uncore, RPM_CONFIG1, GEN10_GT_NOA_ENABLE, 0);
+
+	/* Reset PMON Enable to save power. */
+	intel_uncore_rmw(uncore, GEN12_SQCNT1, GEN12_SQCNT1_PMON_ENABLE, 0);
 }
 
 static void gen7_oa_enable(struct i915_perf_stream *stream)
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 7ea70b7ffcc6..4137ca9d3315 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -699,6 +699,8 @@ static inline bool i915_mmio_reg_valid(i915_reg_t reg)
 #define OABUFFER_SIZE_16M   (7 << 3)
 
 #define GEN12_OA_TLB_INV_CR _MMIO(0xceec)
+#define GEN12_SQCNT1 _MMIO(0x8718)
+#define  GEN12_SQCNT1_PMON_ENABLE REG_BIT(30)
 
 /* Gen12 OAR unit */
 #define GEN12_OAR_OACONTROL _MMIO(0x2960)
-- 
2.20.1