diff --git a/bsp/qemu-vexpress-a9/drivers/board.c b/bsp/qemu-vexpress-a9/drivers/board.c
index e236c68b80..84af3c1ccd 100644
--- a/bsp/qemu-vexpress-a9/drivers/board.c
+++ b/bsp/qemu-vexpress-a9/drivers/board.c
@@ -55,3 +55,8 @@ void rt_hw_board_init(void)
     rt_hw_ipi_handler_install(RT_SCHEDULE_IPI, rt_scheduler_ipi_handler);
 #endif
 }
+
+void rt_hw_us_delay(rt_uint32_t us)
+{
+
+}
diff --git a/bsp/qemu-vexpress-a9/drivers/drv_smc911x.c b/bsp/qemu-vexpress-a9/drivers/drv_smc911x.c
index 2b2253328d..9d52b258af 100644
--- a/bsp/qemu-vexpress-a9/drivers/drv_smc911x.c
+++ b/bsp/qemu-vexpress-a9/drivers/drv_smc911x.c
@@ -33,16 +33,6 @@ struct eth_device_smc911x
 };
 static struct eth_device_smc911x _emac;
 
-int udelay(int value)
-{
-    return 0;
-}
-
-int mdelay(int value)
-{
-    return 0;
-}
-
 #if defined (CONFIG_SMC911X_32_BIT)
 rt_inline uint32_t smc911x_reg_read(struct eth_device_smc911x *dev, uint32_t offset)
 {
diff --git a/components/libc/compilers/common/SConscript b/components/libc/compilers/common/SConscript
index 2ebfc36c4e..b1982aa329 100644
--- a/components/libc/compilers/common/SConscript
+++ b/components/libc/compilers/common/SConscript
@@ -10,7 +10,7 @@ CPPPATH = [cwd]
 if GetDepend('RT_USING_LIBC'):
     src += Glob('*.c')
     if GetDepend('RT_USING_POSIX') == False:
-        SrcRemove(src, ['unistd.c'])
+        SrcRemove(src, ['unistd.c', 'delay.c'])
 elif GetDepend('RT_LIBC_USING_TIME'):
     src += ['time.c']
 
diff --git a/components/libc/compilers/common/delay.c b/components/libc/compilers/common/delay.c
new file mode 100644
index 0000000000..4666258d3b
--- /dev/null
+++ b/components/libc/compilers/common/delay.c
@@ -0,0 +1,41 @@
+/*
+ * Copyright (c) 2006-2021, RT-Thread Development Team
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Change Logs:
+ * Date           Author       Notes
+ * 2021-05-07     Meco Man     first Version
+ */
+#include <rtthread.h>
+#include <rthw.h>
+
+void msleep(unsigned int msecs)
+{
+    rt_thread_mdelay(msecs);
+}
+RTM_EXPORT(msleep);
+
+void ssleep(unsigned int seconds)
+{
+    msleep(seconds * 1000);
+}
+RTM_EXPORT(ssleep);
+
+void mdelay(unsigned long msecs)
+{
+    rt_hw_us_delay(msecs * 1000);
+}
+RTM_EXPORT(mdelay);
+
+void udelay(unsigned long usecs)
+{
+    rt_hw_us_delay(usecs);
+}
+RTM_EXPORT(udelay);
+
+void ndelay(unsigned long nsecs)
+{
+    rt_hw_us_delay(1);
+}
+RTM_EXPORT(ndelay);
diff --git a/components/libc/compilers/common/delay.h b/components/libc/compilers/common/delay.h
new file mode 100644
index 0000000000..f32708af55
--- /dev/null
+++ b/components/libc/compilers/common/delay.h
@@ -0,0 +1,19 @@
+/*
+ * Copyright (c) 2006-2021, RT-Thread Development Team
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Change Logs:
+ * Date           Author       Notes
+ * 2021-05-07     Meco Man     first Version
+ */
+#ifndef __DELAY_H__
+#define __DELAY_H__
+
+void msleep(unsigned int msecs);
+void ssleep(unsigned int seconds);
+void mdelay(unsigned long msecs);
+void udelay(unsigned long usecs);
+void ndelay(unsigned long nsecs);
+
+#endif