timing: add support for x86

Add initial support for X86 and get timestamps from tsc.

Authored-by: Daniel Leung <[email protected]>
Signed-off-by: Anas Nashif <[email protected]>

Author: nashif

arch/x86/CMakeLists.txt

@@ -54,3 +54,9 @@ if (CONFIG_MMU)
 
   add_bin_file_to_the_next_link(pagetables_bin_target pagetables)
 endif()
+
+if(CONFIG_ARCH_HAS_TIMING_FUNCTIONS AND
+    NOT CONFIG_SOC_HAS_TIMING_FUNCTIONS AND
+    NOT CONFIG_BOARD_HAS_TIMING_FUNCTIONS)
+zephyr_library_sources_ifdef(CONFIG_TIMING_FUNCTIONS timing.c)
+endif()

arch/x86/timing.c

@@ -0,0 +1,85 @@
+/*
+ * Copyright (c) 2020 Intel Corporation.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <arch/x86/arch.h>
+#include <kernel.h>
+#include <sys_clock.h>
+#include <timing/timing.h>
+
+static uint64_t tsc_freq;
+
+void timing_x86_init(void)
+{
+	uint32_t cyc_start = k_cycle_get_32();
+	uint64_t tsc_start = z_tsc_read();
+
+	k_busy_wait(10 * USEC_PER_MSEC);
+
+	uint32_t cyc_end = k_cycle_get_32();
+	uint64_t tsc_end = z_tsc_read();
+
+	uint64_t cyc_freq = sys_clock_hw_cycles_per_sec();
+
+	/*
+	 * cycles are in 32-bit, and delta must be
+	 * calculated in 32-bit percision. Or it would
+	 * wrapping around in 64-bit.
+	 */
+	uint64_t dcyc = (uint32_t)cyc_end - (uint32_t)cyc_start;
+
+	uint64_t dtsc = tsc_end - tsc_start;
+
+	tsc_freq = (cyc_freq * dtsc) / dcyc;
+}
+
+uint64_t timing_x86_freq_get(void)
+{
+	return tsc_freq;
+}
+
+void timing_init(void)
+{
+	timing_x86_init();
+}
+void timing_start(void)
+{
+}
+
+void timing_stop(void)
+{
+}
+
+timing_t timing_counter_get(void)
+{
+	return k_cycle_get_32();
+}
+
+uint64_t timing_cycles_get(volatile timing_t *const start,
+				  volatile timing_t *const end)
+{
+	return (*end - *start);
+}
+
+
+uint64_t timing_freq_get(void)
+{
+	return timing_x86_freq_get();
+}
+
+uint64_t timing_cycles_to_ns(uint64_t cycles)
+{
+	return k_cyc_to_ns_floor64(cycles);
+}
+
+uint64_t timing_cycles_to_ns_avg(uint64_t cycles, uint32_t count)
+{
+	return timing_cycles_to_ns(cycles) / count;
+}
+
+uint32_t timing_freq_get_mhz(void)
+{
+	return (uint32_t)(timing_freq_get() / 1000000);
+}