diff --git a/arch/arm/src/cxd56xx/cxd56_gnss.c b/arch/arm/src/cxd56xx/cxd56_gnss.c
index a5c809f6d1..dba45bcb4f 100644
--- a/arch/arm/src/cxd56xx/cxd56_gnss.c
+++ b/arch/arm/src/cxd56xx/cxd56_gnss.c
@@ -1,7 +1,7 @@
 /****************************************************************************
  * arch/arm/src/cxd56xx/cxd56_gnss.c
  *
- *   Copyright 2018,2019 Sony Semiconductor Solutions Corporation
+ *   Copyright 2018, 2019 Sony Semiconductor Solutions Corporation
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -48,11 +48,14 @@
 #include <debug.h>
 
 #include <nuttx/kmalloc.h>
-#include <nuttx/fs/fs.h>
 #include <nuttx/board.h>
+#include <nuttx/signal.h>
+#include <nuttx/fs/fs.h>
 #include <nuttx/spi/spi.h>
+
 #include <arch/chip/gnss.h>
 #include <arch/board/board.h>
+
 #include "cxd56_gnss_api.h"
 #include "cxd56_cpu1signal.h"
 #include "cxd56_gnss.h"
@@ -403,7 +406,7 @@ static int cxd56_gnss_start(FAR struct file *filep, unsigned long arg)
     {
       /* GNSS requires stable RTC */
 
-      usleep(100 * 1000);
+      nxsig_usleep(100 * 1000);
     }
 
   ret = cxd56_gnss_cpufifo_api(filep, CXD56_GNSS_GD_GNSS_START,
@@ -1311,7 +1314,7 @@ static int cxd56_gnss_start_test(FAR struct file *filep, unsigned long arg)
         {
           /* GNSS requires stable RTC */
 
-          usleep(100 * 1000);
+          nxsig_usleep(100 * 1000);
         }
 
       /* set parameter */
diff --git a/arch/arm/src/cxd56xx/cxd56_sdhci.c b/arch/arm/src/cxd56xx/cxd56_sdhci.c
index 94949533be..d991b96ce6 100644
--- a/arch/arm/src/cxd56xx/cxd56_sdhci.c
+++ b/arch/arm/src/cxd56xx/cxd56_sdhci.c
@@ -53,12 +53,13 @@
 #include <nuttx/wdog.h>
 #include <nuttx/clock.h>
 #include <nuttx/arch.h>
+#include <nuttx/signal.h>
 #include <nuttx/sdio.h>
 #include <nuttx/wqueue.h>
 #include <nuttx/mmcsd.h>
 #include <nuttx/kmalloc.h>
-
 #include <nuttx/irq.h>
+
 #include <arch/board/board.h>
 
 #include "chip.h"
@@ -4305,10 +4306,12 @@ static int cxd56_sdio_initialize(struct cxd56_sdiodev_s *priv)
             {
               cxd56_sdio_recvshort(&priv->dev, SDIO_CMD5, &response);
             }
-          usleep(4000);
+
+          nxsig_usleep(4000);
         }
       while ((response == 0xffffffff) ||
                 ((response & 0x80000000) == 0));
+
       mcinfo("response = 0x%x, card is ready(MSB=1)\n", response);
       priv->sc.func_num = SDIO_OCR_NUM_FUNCTIONS(response) + 1;
     }
@@ -4642,7 +4645,8 @@ void cxd56_sdhci_mediachange(FAR struct sdio_dev_s *dev)
             {
               break;
             }
-          usleep(100000);
+
+          nxsig_usleep(100000);
           timeout -= 100000;
         }
     }
diff --git a/arch/arm/src/lc823450/lc823450_i2s.c b/arch/arm/src/lc823450/lc823450_i2s.c
index 9607f9ae6a..bfa63d8dde 100644
--- a/arch/arm/src/lc823450/lc823450_i2s.c
+++ b/arch/arm/src/lc823450/lc823450_i2s.c
@@ -1,7 +1,7 @@
 /****************************************************************************
  * arch/arm/src/lc823450/lc823450_i2s.c
  *
- *   Copyright 2017,2018 Sony Video & Sound Products Inc.
+ *   Copyright 2017, 2018 Sony Video & Sound Products Inc.
  *   Author: Masayuki Ishikawa <Masayuki.Ishikawa@jp.sony.com>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -41,21 +41,17 @@
 #include <nuttx/config.h>
 
 #include <semaphore.h>
-#include <nuttx/arch.h>
 #include <errno.h>
 #include <debug.h>
 
 #include <nuttx/sched.h>
 #include <nuttx/arch.h>
+#include <nuttx/signal.h>
 #include <nuttx/kmalloc.h>
 #include <nuttx/semaphore.h>
 #include <nuttx/audio/audio.h>
 #include <nuttx/audio/i2s.h>
 
-#ifdef CONFIG_SMP
-#  include <nuttx/signal.h>
-#endif
-
 #include "up_arch.h"
 #include "lc823450_dma.h"
 #include "lc823450_i2s.h"
@@ -303,7 +299,7 @@ static void _setup_audio_pll(uint32_t freq)
 
   /* TODO: Wait */
 
-  usleep(50 * 1000);
+  nxsig_usleep(50 * 1000);
 
   /* Switch to the PLL */
 
diff --git a/arch/arm/src/lc823450/lc823450_ipl2.c b/arch/arm/src/lc823450/lc823450_ipl2.c
index 79db920c0f..8d528b973c 100644
--- a/arch/arm/src/lc823450/lc823450_ipl2.c
+++ b/arch/arm/src/lc823450/lc823450_ipl2.c
@@ -40,19 +40,6 @@
  ****************************************************************************/
 
 #include <nuttx/config.h>
-#include <nuttx/arch.h>
-
-#ifdef CONFIG_FS_EVFAT
-#  include <nuttx/fs/mkevfatfs.h>
-#endif
-
-#include <nuttx/usb/usbmsc.h>
-#include <nuttx/mtd/mtd.h>
-#include <nuttx/drivers/drivers.h>
-
-#ifdef CONFIG_I2C
-#  include <nuttx/i2c.h>
-#endif
 
 #include <sys/types.h>
 #include <sys/stat.h>
@@ -66,6 +53,21 @@
 #include <unistd.h>
 #include <errno.h>
 
+#include <nuttx/arch.h>
+#include <nuttx/signal.h>
+
+#ifdef CONFIG_FS_EVFAT
+#  include <nuttx/fs/mkevfatfs.h>
+#endif
+
+#include <nuttx/usb/usbmsc.h>
+#include <nuttx/mtd/mtd.h>
+#include <nuttx/drivers/drivers.h>
+
+#ifdef CONFIG_I2C
+#  include <nuttx/i2c.h>
+#endif
+
 #ifdef CONFIG_LASTKMSG
 #  include <nuttx/lastkmsg.h>
 #endif /* CONFIG_LASTKMSG */
@@ -371,7 +373,7 @@ static int check_forceusbboot(void)
   modifyreg32(MCLKCNTAPB, 0, MCLKCNTAPB_ADC_CLKEN);
   modifyreg32(MRSTCNTAPB, 0, MRSTCNTAPB_ADC_RSTB);
 
-  usleep(10000);
+  nxsig_usleep(10000);
 
   /* start ADC0,1 */
 
@@ -430,7 +432,7 @@ static void sysreset(void)
 {
   /* workaround to flush eMMC cache */
 
-  usleep(100000);
+  nxsig_usleep(100000);
 
   up_systemreset();
 }
@@ -534,7 +536,7 @@ static void chg_disable(void)
             }
           else
             {
-              usleep(20);
+              nxsig_usleep(20);
             }
         }
 
@@ -581,7 +583,8 @@ static int msc_enable(int forced)
           usbmsc_uninitialize(handle);
           return 0;
         }
-      usleep(10000);
+
+      nxsig_usleep(10000);
     }
 
 #else
@@ -589,7 +592,7 @@ static int msc_enable(int forced)
 
   while (g_update_flag == 0)
     {
-      usleep(10000);
+      nxsig_usleep(10000);
     }
 #endif
 
@@ -598,7 +601,7 @@ static int msc_enable(int forced)
   /* check recovery kernel update */
 
   mount(CONFIG_MTD_CP_DEVPATH, "/mnt/sd0", "evfat", 0, NULL);
-  usleep(10000);
+  nxsig_usleep(10000);
 
   /* recovery kernel install from UPG.img */
 
@@ -671,7 +674,7 @@ void check_lastkmsg(void)
 
   /* XXX: workaround for logfile size = 0 */
 
-  usleep(100000);
+  nxsig_usleep(100000);
 }
 #endif /* CONFIG_LASTKMSG */
 
@@ -740,7 +743,7 @@ int ipl2_main(int argc, char *argv[])
       /* check recovery kernel update */
 
       mount(CONFIG_MTD_CP_DEVPATH, "/mnt/sd0", "evfat", 0, NULL);
-      usleep(10000);
+      nxsig_usleep(10000);
 
       /* recovery kernel install from UPG.img */
 
diff --git a/arch/arm/src/lpc17xx_40xx/lpc17_40_ethernet.c b/arch/arm/src/lpc17xx_40xx/lpc17_40_ethernet.c
index 003eba909a..ac1e39f303 100644
--- a/arch/arm/src/lpc17xx_40xx/lpc17_40_ethernet.c
+++ b/arch/arm/src/lpc17xx_40xx/lpc17_40_ethernet.c
@@ -54,6 +54,7 @@
 #include <nuttx/irq.h>
 #include <nuttx/arch.h>
 #include <nuttx/wqueue.h>
+#include <nuttx/signal.h>
 #include <nuttx/net/mii.h>
 #include <nuttx/net/netconfig.h>
 #include <nuttx/net/arp.h>
@@ -2741,7 +2742,7 @@ static inline int lpc17_40_phyinit(struct lpc17_40_driver_s *priv)
 
   while ((lpc17_40_phyread(phyaddr, MII_DP83848C_STS) & 0x0001) == 0)
     {
-      usleep(40000);
+      nxsig_usleep(40000);
     }
 #endif
 
diff --git a/arch/arm/src/stm32h7/stm32_sdmmc.c b/arch/arm/src/stm32h7/stm32_sdmmc.c
index 708a0fdc12..824150a3d8 100644
--- a/arch/arm/src/stm32h7/stm32_sdmmc.c
+++ b/arch/arm/src/stm32h7/stm32_sdmmc.c
@@ -55,12 +55,13 @@
 #include <nuttx/sdio.h>
 #include <nuttx/wqueue.h>
 #include <nuttx/semaphore.h>
+#include <nuttx/signal.h>
 #include <nuttx/mmcsd.h>
-
 #include <nuttx/irq.h>
+#include <nuttx/cache.h>
+
 #include <arch/board/board.h>
 
-#include <nuttx/cache.h>
 #include "chip.h"
 #include "up_arch.h"
 
@@ -1779,11 +1780,11 @@ static void stm32_reset(FAR struct sdio_dev_s *dev)
 
   regval = getreg32(regaddress);
   putreg32(regval | restval, regaddress);
-  usleep(2);
+  nxsig_usleep(2);
   putreg32(regval, regaddress);
 
   stm32_setpwrctrl(priv, STM32_SDMMC_POWER_PWRCTRL_CYCLE);
-  usleep(1000);
+  nxsig_usleep(1000);
 
   /* Put SDIO registers in their default, reset state */
 
@@ -1808,7 +1809,7 @@ static void stm32_reset(FAR struct sdio_dev_s *dev)
   /* Configure the SDIO peripheral */
 
   stm32_setpwrctrl(priv, STM32_SDMMC_POWER_PWRCTRL_OFF);
-  usleep(1000);
+  nxsig_usleep(1000);
   stm32_setpwrctrl(priv, STM32_SDMMC_POWER_PWRCTRL_ON);
 
   stm32_setclkcr(priv, STM32_CLCKCR_INIT);