[Intel-gfx] [PATCH 1/4] 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)

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>
---
 drivers/gpu/drm/i915/i915_perf.c | 8 ++++++++
 drivers/gpu/drm/i915/i915_reg.h  | 2 ++
 2 files changed, 10 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c
index c6f6370283cf..88610d52f30b 100644
--- a/drivers/gpu/drm/i915/i915_perf.c
+++ b/drivers/gpu/drm/i915/i915_perf.c
@@ -2493,6 +2493,14 @@ 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_write(uncore, GEN12_SQCNT1,
+			   intel_uncore_read(uncore, GEN12_SQCNT1) |
+			   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
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index b9607ac3620d..1638f1282541 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -696,6 +696,8 @@ 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 (1 << 30)
 
 /* Gen12 OAR unit */
 #define GEN12_OAR_OACONTROL _MMIO(0x2960)
-- 
2.20.1