hv/mod_timer: split tsc handling code from timer.

Generalize and split basic cpu cycle/tick routines from x86/timer:
- Instead of rdstc(), use cpu_ticks() in generic code.
- Instead of get_tsc_khz(), use cpu_tickrate() in generic code.
- Include "common/ticks.h" instead of "x86/timer.h" in generic code.
- CYCLES_PER_MS is renamed to TICKS_PER_MS.

The x86 specific API rdstc() and get_tsc_khz(), as well as TSC_PER_MS
are still available in arch/x86/tsc.h but only for x86 specific usage.

Tracked-On: #5920
Signed-off-by: Rong Liu <rong2.liu@intel.com>
Signed-off-by: Yi Liang <yi.liang@intel.com>

hypervisor/include/common/ticks.h

@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) 2021 Intel Corporation.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef COMMON_TICKS_H
+#define COMMON_TICKS_H
+
+#include <types.h>
+
+#define TICKS_PER_MS	us_to_ticks(1000U)
+
+/**
+ * @brief Read current CPU tick count.
+ *
+ * @return CPU ticks
+ */
+uint64_t cpu_ticks(void);
+
+/**
+ * @brief  Get CPU tick frequency in KHz.
+ *
+ * @return CPU frequency (KHz)
+ */
+uint32_t cpu_tickrate(void);
+
+/**
+ * @brief Convert micro seconds to CPU ticks.
+ *
+ * @param[in] us micro seconds to convert
+ * @return CPU ticks
+ */
+uint64_t us_to_ticks(uint32_t us);
+
+/**
+ * @brief Convert CPU cycles to micro seconds.
+ *
+ * @param[in] ticks CPU ticks to convert
+ * @return microsecond
+ */
+uint64_t ticks_to_us(uint64_t ticks);
+
+/**
+ * @brief Convert CPU cycles to milli seconds.
+ *
+ * @param[in] ticks CPU ticks to convert
+ * @return millisecond
+ */
+uint64_t ticks_to_ms(uint64_t ticks);
+
+#endif	/* COMMON_TICKS_H */
+