建立工程，成功创建两个虚拟串口

source/rt_thread/libcpu/risc-v/k210/tick.c

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+/*
+ * Copyright (c) 2006-2021, RT-Thread Development Team
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Change Logs:
+ * Date           Author       Notes
+ * 2018/10/28     Bernard      The unify RISC-V porting code.
+ */
+
+#include <rthw.h>
+#include <rtthread.h>
+
+#include <encoding.h>
+#include <clint.h>
+#include <sysctl.h>
+
+static volatile unsigned long tick_cycles = 0;
+int tick_isr(void)
+{
+    uint64_t core_id = current_coreid();
+
+    clint->mtimecmp[core_id] += tick_cycles;
+    rt_tick_increase();
+
+    return 0;
+}
+
+/* Sets and enable the timer interrupt */
+int rt_hw_tick_init(void)
+{
+    /* Read core id */
+    unsigned long core_id = current_coreid();
+    unsigned long interval = 1000/RT_TICK_PER_SECOND;
+
+    /* Clear the Machine-Timer bit in MIE */
+    clear_csr(mie, MIP_MTIP);
+
+    /* calculate the tick cycles */
+    tick_cycles = interval * sysctl_clock_get_freq(SYSCTL_CLOCK_CPU) / CLINT_CLOCK_DIV / 1000ULL - 1;
+    /* Set mtimecmp by core id */
+    clint->mtimecmp[core_id] = clint->mtime + tick_cycles;
+
+    /* Enable the Machine-Timer bit in MIE */
+    set_csr(mie, MIP_MTIP);
+
+    return 0;
+}