From d5112700d2f5673d9151338f4861c50b019552ef Mon Sep 17 00:00:00 2001
From: Michalis Spyrou <michalis.spyrou@arm.com>
Date: Wed, 27 Jan 2021 14:52:46 +0000
Subject: Add WallClockTimer support for bare metal.

Change-Id: I8f92a71fc6f5190ca3bb664208244f8bff1270af
Signed-off-by: Michalis Spyrou <michalis.spyrou@arm.com>
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/5066
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Giorgio Arena <giorgio.arena@arm.com>
Reviewed-by: Georgios Pinitas <georgios.pinitas@arm.com>
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
---
 tests/framework/instruments/WallClockTimer.cpp | 44 ++++++++++++++++++++++++--
 tests/framework/instruments/WallClockTimer.h   | 11 +++++--
 2 files changed, 50 insertions(+), 5 deletions(-)

diff --git a/tests/framework/instruments/WallClockTimer.cpp b/tests/framework/instruments/WallClockTimer.cpp
index 9063da0613..763fb9ab27 100644
--- a/tests/framework/instruments/WallClockTimer.cpp
+++ b/tests/framework/instruments/WallClockTimer.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017-2019 Arm Limited.
+ * Copyright (c) 2017-2021 Arm Limited.
  *
  * SPDX-License-Identifier: MIT
  *
@@ -48,13 +48,44 @@ std::string    WallClock<output_timestamps>::id() const
 template <bool output_timestamps>
 void           WallClock<output_timestamps>::start()
 {
+#if defined(BARE_METAL)
+    uint64_t tmp;
+    uint64_t retval;
+
+    __asm __volatile(
+        "mrs    %[tmp], pmcr_el0\n"
+        "orr    %[tmp], %[tmp], #1\n"
+        "msr    pmcr_el0, %[tmp]\n"
+        "mrs    %[tmp], pmcntenset_el0\n"
+        "orr    %[tmp], %[tmp], #1<<31\n"
+        "msr    pmcntenset_el0, %[tmp]\n"
+        "mrs    %[retval], pmccntr_el0\n"
+        : [tmp] "=r"(tmp), [retval] "=r"(retval));
+
+    _start = retval;
+#else  // !defined(BARE_METAL)
     _start = std::chrono::system_clock::now();
+#endif // defined(BARE_METAL)
 }
 
 template <bool output_timestamps>
 void           WallClock<output_timestamps>::stop()
 {
+#if defined(BARE_METAL)
+    uint64_t tmp;
+    uint64_t retval;
+
+    __asm __volatile(
+        "mrs    %[retval], pmccntr_el0\n"
+        "mov   %[tmp], #0x3f\n"
+        "orr   %[tmp], %[tmp], #1<<31\n"
+        "msr    pmcntenclr_el0, %[tmp]\n"
+        : [tmp] "=r"(tmp), [retval] "=r"(retval));
+
+    _stop = retval;
+#else  // !defined(BARE_METAL)
     _stop = std::chrono::system_clock::now();
+#endif // defined(BARE_METAL)
 }
 
 template <bool              output_timestamps>
@@ -63,14 +94,23 @@ Instrument::MeasurementsMap WallClock<output_timestamps>::measurements() const
     MeasurementsMap measurements;
     if(output_timestamps)
     {
-        // _start / _stop are in ns, so divide by an extra 1000:
+#if defined(BARE_METAL)
+        measurements.emplace("[start]Wall clock time", Measurement(_start / static_cast<uint64_t>(_scale_factor), _unit));
+        measurements.emplace("[end]Wall clock time", Measurement(_stop / static_cast<uint64_t>(_scale_factor), _unit));
+#else  // !defined(BARE_METAL)
         measurements.emplace("[start]Wall clock time", Measurement(_start.time_since_epoch().count() / static_cast<uint64_t>(1000 * _scale_factor), _unit));
         measurements.emplace("[end]Wall clock time", Measurement(_stop.time_since_epoch().count() / static_cast<uint64_t>(1000 * _scale_factor), _unit));
+#endif // defined(BARE_METAL)
     }
     else
     {
+#if defined(BARE_METAL)
+        const double delta = _stop - _start;
+        measurements.emplace("Wall clock time", Measurement(delta / static_cast<double>(1000 * _scale_factor), _unit));
+#else  // !defined(BARE_METAL)
         const auto delta = std::chrono::duration_cast<std::chrono::microseconds>(_stop - _start);
         measurements.emplace("Wall clock time", Measurement(delta.count() / _scale_factor, _unit));
+#endif // defined(BARE_METAL)
     }
     return measurements;
 }
diff --git a/tests/framework/instruments/WallClockTimer.h b/tests/framework/instruments/WallClockTimer.h
index 1ca4fe2c36..b1d7531f4e 100644
--- a/tests/framework/instruments/WallClockTimer.h
+++ b/tests/framework/instruments/WallClockTimer.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017-2019 Arm Limited.
+ * Copyright (c) 2017-2021 Arm Limited.
  *
  * SPDX-License-Identifier: MIT
  *
@@ -70,9 +70,14 @@ public:
     MeasurementsMap measurements() const override;
 
 private:
-    std::chrono::system_clock::time_point _start{};
+#if defined(BARE_METAL)
+    uint64_t _start {};
+    uint64_t _stop{};
+#else  // !defined(BARE_METAL)
+    std::chrono::system_clock::time_point _start {};
     std::chrono::system_clock::time_point _stop{};
-    float                                 _scale_factor{};
+#endif // defined(BARE_METAL)
+    float _scale_factor {};
 };
 
 using WallClockTimer      = WallClock<false>;
-- 
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