sched/hrtimer: add a high resolution timer module in sched and tricore porting to support hard real time cases

[wangchdo]

Add a high resolution timer module in sched to support hard real time cases

Note: Please adhere to Contributing Guidelines.

Summary

Nuttx only provide wdog for delayed function execution, wdog is mainly used for OS-internal timeouts (e.g., task scheduling, time slicing) and periodic callbacks. Resolution depends on system tick.

This PR introduces hrtimer to Nuttx acting as a high-resolution timer, it can deliver deliver precise timing events (nanosecond or microsecond accuracy).

hrtimer VS wdog:

Purpose: hrtimer: High-resolution timer for precise event scheduling.
wdog: Lightweight software timer for delayed callbacks and OS timeouts. Resolution: hrtimer: Nanosecond / microsecond accuracy, independent of system tick.
wdog: tick-based (ms level) Accuracy: hrtimer: Very high, suitable for hard real-time and multimedia workloads.
wdog: Limited by system tick; not sufficient for hard real-time control. Implementation: hrtimer: rb tree for timers, sorted by expiration,
wdog: Linked list of timers, sorted by expiration, integrated into scheduler. Usage Pattern hrtimer: Create with hrtimer_int(), start with hrtimer_start(), cancel with hrtimer_cancel().
wdog:Allocate wdog_t, start with wd_start(), cancel with wd_cancel(). Callback Context: hrtimer: Runs in interrupt context
wdog: Runs in interrupt context(scheduler tick or hrtimer). Use Cases hrtimer: Precise scheduling, hard RT tasks, multimedia, networking, low-latency wake-ups
wdog: Task time slicing,timeout handling, simple periodic events. Complexity hrtimer: A little Complex using rb-tree, but optimized for embedded RTOS,
wdog: Simple and lightweight; Footprint : hrtimer: Larger memory and CPU overhead.
wdog: Minimal memory and CPU usage.

Impact

A new module added in sched,

if CONFIG_HRTIMER is enabled:

1. new functions will be introduced, hrtimer_init(), hrtimer_start(), hrtimer_cancel()
2. wdog will be driven by hrtimer as a timer

if CONFIG_HRTIMER is not enabled: nothing happen

Testing

enable hrtimer in a2g-tc397-5v-tft:

ostest passed

[simbit18]

Hi @wangchdo, has it also been tested with Make?

[wangchdo]

Hi @wangchdo, has it also been tested with Make?

Not, yet,I will upload a Makefile update soon

[wangchdo]

Hi @wangchdo, has it also been tested with Make?

I uploaded the Makefile update, and the test also passed with Make

[acassis]

@wangchdo I'm ok with this PR, but please answer @GUIDINGLI questions/suggestions.