Merge branch 'master' into usbh_construct

30 files changed, 1708 insertions, 155 deletions

diff --git a/components/libc/compilers/common/SConscript b/components/libc/compilers/common/SConscript
index ecdee2637e..b1982aa329 100644
--- a/components/libc/compilers/common/SConscript
+++ b/components/libc/compilers/common/SConscript
@@ -9,19 +9,22 @@ CPPPATH = [cwd]
 
 if GetDepend('RT_USING_LIBC'):
     src += Glob('*.c')
-else:
-    if GetDepend('RT_LIBC_USING_TIME') and not GetDepend('RT_USING_MINILIBC'):
-        src += ['time.c']
-
-if GetDepend('RT_USING_POSIX') == False:
-    SrcRemove(src, ['unistd.c'])
+    if GetDepend('RT_USING_POSIX') == False:
+        SrcRemove(src, ['unistd.c', 'delay.c'])
+elif GetDepend('RT_LIBC_USING_TIME'):
+    src += ['time.c']
 
 if rtconfig.CROSS_TOOL == 'keil':
     CPPDEFINES = ['__CLK_TCK=RT_TICK_PER_SECOND']
 else:
     CPPDEFINES = []
 
-if not GetDepend('RT_USING_MINILIBC') and (GetDepend('RT_USING_LIBC') or GetDepend('RT_LIBC_USING_TIME')):
-    group = DefineGroup('libc', src, depend = [''], CPPPATH = CPPPATH, CPPDEFINES = CPPDEFINES)
+group = DefineGroup('libc', src, depend = [], CPPPATH = CPPPATH, CPPDEFINES = CPPDEFINES)
+
+list = os.listdir(cwd)
+for d in list:
+    path = os.path.join(cwd, d)
+    if os.path.isfile(os.path.join(path, 'SConscript')):
+        group = group + SConscript(os.path.join(d, 'SConscript'))
 
 Return('group')
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
diff --git a/components/libc/compilers/common/dirent.h b/components/libc/compilers/common/dirent.h
new file mode 100644
index 0000000000..a6353fd6f8
--- /dev/null
+++ b/components/libc/compilers/common/dirent.h
@@ -0,0 +1,70 @@
+/*
+ * Copyright (c) 2006-2021, RT-Thread Development Team
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Change Logs:
+ * Date           Author       Notes
+ */
+#ifndef __DIRENT_H__
+#define __DIRENT_H__
+
+#include <rtdef.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*
+* dirent.h - format of directory entries
+ * Ref: http://www.opengroup.org/onlinepubs/009695399/basedefs/dirent.h.html
+ */
+
+/* File types */
+#define FT_REGULAR      0   /* regular file */
+#define FT_SOCKET       1   /* socket file  */
+#define FT_DIRECTORY    2   /* directory    */
+#define FT_USER         3   /* user defined */
+
+#define DT_UNKNOWN      0x00
+#define DT_REG          0x01
+#define DT_DIR          0x02
+
+#ifndef HAVE_DIR_STRUCTURE
+#define HAVE_DIR_STRUCTURE
+typedef struct
+{
+    int fd;                         /* directory file */
+    char buf[512];
+    int num;
+    int cur;
+}DIR;
+#endif
+
+#ifndef HAVE_DIRENT_STRUCTURE
+#define HAVE_DIRENT_STRUCTURE
+
+#define DIRENT_NAME_MAX    256
+
+struct dirent
+{
+    rt_uint8_t  d_type;             /* The type of the file */
+    rt_uint8_t  d_namlen;           /* The length of the not including the terminating null file name */
+    rt_uint16_t d_reclen;           /* length of this record */
+    char d_name[DIRENT_NAME_MAX];   /* The null-terminated file name */
+};
+#endif
+
+int            closedir(DIR *);
+DIR           *opendir(const char *);
+struct dirent *readdir(DIR *);
+int            readdir_r(DIR *, struct dirent *, struct dirent **);
+void           rewinddir(DIR *);
+void           seekdir(DIR *, long int);
+long           telldir(DIR *);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/components/libc/compilers/common/fcntl.h b/components/libc/compilers/common/fcntl.h
new file mode 100644
index 0000000000..3460926708
--- /dev/null
+++ b/components/libc/compilers/common/fcntl.h
@@ -0,0 +1,67 @@
+/*
+ * Copyright (c) 2006-2021, RT-Thread Development Team
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Change Logs:
+ * Date           Author       Notes
+ * 2021-09-02     Meco Man     First version
+ */
+#ifndef __FCNTL_H__
+#define __FCNTL_H__
+
+#include <sys/types.h>
+
+#define O_RDONLY    0x0000      /* open for reading only */
+#define O_WRONLY    0x0001      /* open for writing only */
+#define O_RDWR      0x0002      /* open for reading and writing */
+#define O_ACCMODE   0x0003      /* mask for above modes */
+
+#define O_CREAT        0100
+#define O_EXCL         0200
+#define O_NOCTTY       0400
+#define O_TRUNC       01000
+#define O_APPEND      02000
+#define O_NONBLOCK    04000
+#define O_DSYNC      010000
+#define O_SYNC     04010000
+#define O_RSYNC    04010000
+#define O_BINARY    0100000
+#define O_DIRECTORY 0200000
+#define O_NOFOLLOW  0400000
+#define O_CLOEXEC  02000000
+#define O_ASYNC      020000
+#define O_DIRECT     040000
+#define O_LARGEFILE 0100000
+#define O_NOATIME  01000000
+#define O_PATH    010000000
+#define O_TMPFILE 020200000
+#define O_NDELAY O_NONBLOCK
+#define O_SEARCH  O_PATH
+#define O_EXEC    O_PATH
+
+#define F_DUPFD  0
+#define F_GETFD  1
+#define F_SETFD  2
+#define F_GETFL  3
+#define F_SETFL  4
+
+#define F_SETOWN 8
+#define F_GETOWN 9
+#define F_SETSIG 10
+#define F_GETSIG 11
+
+#define F_GETLK 12
+#define F_SETLK 13
+#define F_SETLKW 14
+
+#define F_SETOWN_EX 15
+#define F_GETOWN_EX 16
+
+#define F_GETOWNER_UIDS 17
+
+int open(const char *file, int flags, ...);
+int fcntl(int fildes, int cmd, ...);
+int creat(const char *, mode_t);
+
+#endif
diff --git a/components/libc/compilers/common/nogcc/SConscript b/components/libc/compilers/common/nogcc/SConscript
new file mode 100644
index 0000000000..c766c8f82d
--- /dev/null
+++ b/components/libc/compilers/common/nogcc/SConscript
@@ -0,0 +1,15 @@
+from building import *
+
+Import('rtconfig')
+
+src   = []
+cwd   = GetCurrentDir()
+CPPPATH = [cwd]
+group = []
+
+if GetDepend('RT_USING_LIBC'):
+    src += Glob('*.c')
+
+if rtconfig.PLATFORM != 'gcc' or rtconfig.ARCH == 'sim':
+    group = DefineGroup('libc', src, depend = [], CPPPATH = CPPPATH)
+Return('group')
diff --git a/components/libc/compilers/common/nogcc/readme.md b/components/libc/compilers/common/nogcc/readme.md
new file mode 100644
index 0000000000..b10940d003
--- /dev/null
+++ b/components/libc/compilers/common/nogcc/readme.md
@@ -0,0 +1,3 @@
+## Attentions
+
+This folder is "common" for toolchains excluding gcc.
\ No newline at end of file
diff --git a/components/libc/compilers/common/nogcc/sys/errno.h b/components/libc/compilers/common/nogcc/sys/errno.h
new file mode 100644
index 0000000000..ff1abca387
--- /dev/null
+++ b/components/libc/compilers/common/nogcc/sys/errno.h
@@ -0,0 +1,197 @@
+/*
+ * Copyright (c) 2006-2021, RT-Thread Development Team
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Change Logs:
+ * Date           Author       Notes
+ * 2021-05-22     Meco Man     The first version.
+ */
+#ifndef __SYS_ERRNO_H__
+#define __SYS_ERRNO_H__
+
+#if defined(__ARMCC_VERSION)
+/*
+defined in armcc/errno.h
+
+#define EDOM    1
+#define ERANGE  2
+#define EILSEQ  4
+#define ESIGNUM 3
+#define EINVAL  5
+#define ENOMEM  6
+*/
+
+#define ERROR_BASE_NO    7
+
+#elif defined(__IAR_SYSTEMS_ICC__)
+/* defined in iar/errno.h
+#define EDOM    33
+#define ERANGE  34
+#define EFPOS   35
+#define EILSEQ  36
+*/
+#define ERROR_BASE_NO    36
+
+#else
+#define ERROR_BASE_NO    0
+#endif
+
+#if defined(__ARMCC_VERSION) || defined(__IAR_SYSTEMS_ICC__)
+#include <errno.h>
+#define EPERM            (ERROR_BASE_NO + 1)
+#define ENOENT           (ERROR_BASE_NO + 2)
+#define ESRCH            (ERROR_BASE_NO + 3)
+#define EINTR            (ERROR_BASE_NO + 4)
+#define EIO              (ERROR_BASE_NO + 5)
+#define ENXIO            (ERROR_BASE_NO + 6)
+#define E2BIG            (ERROR_BASE_NO + 7)
+#define ENOEXEC          (ERROR_BASE_NO + 8)
+#define EBADF            (ERROR_BASE_NO + 9)
+#define ECHILD          (ERROR_BASE_NO + 10)
+#define EAGAIN          (ERROR_BASE_NO + 11)
+
+#ifndef ENOMEM
+#define ENOMEM          (ERROR_BASE_NO + 12)
+#endif
+
+#define EACCES          (ERROR_BASE_NO + 13)
+#define EFAULT          (ERROR_BASE_NO + 14)
+#define ENOTBLK         (ERROR_BASE_NO + 15)
+#define EBUSY           (ERROR_BASE_NO + 16)
+#define EEXIST          (ERROR_BASE_NO + 17)
+#define EXDEV           (ERROR_BASE_NO + 18)
+#define ENODEV          (ERROR_BASE_NO + 19)
+#define ENOTDIR         (ERROR_BASE_NO + 20)
+#define EISDIR          (ERROR_BASE_NO + 21)
+
+#ifndef EINVAL
+#define EINVAL          (ERROR_BASE_NO + 22)
+#endif
+
+#define ENFILE          (ERROR_BASE_NO + 23)
+#define EMFILE          (ERROR_BASE_NO + 24)
+#define ENOTTY          (ERROR_BASE_NO + 25)
+#define ETXTBSY         (ERROR_BASE_NO + 26)
+#define EFBIG           (ERROR_BASE_NO + 27)
+#define ENOSPC          (ERROR_BASE_NO + 28)
+#define ESPIPE          (ERROR_BASE_NO + 29)
+#define EROFS           (ERROR_BASE_NO + 30)
+#define EMLINK          (ERROR_BASE_NO + 31)
+#define EPIPE           (ERROR_BASE_NO + 32)
+
+#ifndef EDOM
+#define EDOM            (ERROR_BASE_NO + 33)
+#endif
+
+#ifndef ERANGE
+#define ERANGE          (ERROR_BASE_NO + 34)
+#endif
+
+#define EDEADLK         (ERROR_BASE_NO + 35)
+#define ENAMETOOLONG    (ERROR_BASE_NO + 36)
+#define ENOLCK          (ERROR_BASE_NO + 37)
+#define ENOSYS          (ERROR_BASE_NO + 38)
+#define ENOTEMPTY       (ERROR_BASE_NO + 39)
+#define ELOOP           (ERROR_BASE_NO + 40)
+#define EWOULDBLOCK     EAGAIN
+#define ENOMSG          (ERROR_BASE_NO + 42)
+#define EIDRM           (ERROR_BASE_NO + 43)
+#define ECHRNG          (ERROR_BASE_NO + 44)
+#define EL2NSYNC        (ERROR_BASE_NO + 45)
+#define EL3HLT          (ERROR_BASE_NO + 46)
+#define EL3RST          (ERROR_BASE_NO + 47)
+#define ELNRNG          (ERROR_BASE_NO + 48)
+#define EUNATCH         (ERROR_BASE_NO + 49)
+#define ENOCSI          (ERROR_BASE_NO + 50)
+#define EL2HLT          (ERROR_BASE_NO + 51)
+#define EBADE           (ERROR_BASE_NO + 52)
+#define EBADR           (ERROR_BASE_NO + 53)
+#define EXFULL          (ERROR_BASE_NO + 54)
+#define ENOANO          (ERROR_BASE_NO + 55)
+#define EBADRQC         (ERROR_BASE_NO + 56)
+#define EBADSLT         (ERROR_BASE_NO + 57)
+#define EDEADLOCK       EDEADLK
+#define EBFONT          (ERROR_BASE_NO + 59)
+#define ENOSTR          (ERROR_BASE_NO + 60)
+#define ENODATA         (ERROR_BASE_NO + 61)
+#define ETIME           (ERROR_BASE_NO + 62)
+#define ENOSR           (ERROR_BASE_NO + 63)
+#define ENONET          (ERROR_BASE_NO + 64)
+#define ENOPKG          (ERROR_BASE_NO + 65)
+#define EREMOTE         (ERROR_BASE_NO + 66)
+#define ENOLINK         (ERROR_BASE_NO + 67)
+#define EADV            (ERROR_BASE_NO + 68)
+#define ESRMNT          (ERROR_BASE_NO + 69)
+#define ECOMM           (ERROR_BASE_NO + 70)
+#define EPROTO          (ERROR_BASE_NO + 71)
+#define EMULTIHOP       (ERROR_BASE_NO + 72)
+#define EDOTDOT         (ERROR_BASE_NO + 73)
+#define EBADMSG         (ERROR_BASE_NO + 74)
+#define EOVERFLOW       (ERROR_BASE_NO + 75)
+#define ENOTUNIQ        (ERROR_BASE_NO + 76)
+#define EBADFD          (ERROR_BASE_NO + 77)
+#define EREMCHG         (ERROR_BASE_NO + 78)
+#define ELIBACC         (ERROR_BASE_NO + 79)
+#define ELIBBAD         (ERROR_BASE_NO + 80)
+#define ELIBSCN         (ERROR_BASE_NO + 81)
+#define ELIBMAX         (ERROR_BASE_NO + 82)
+#define ELIBEXEC        (ERROR_BASE_NO + 83)
+
+#ifndef EILSEQ
+#define EILSEQ          (ERROR_BASE_NO + 84)
+#endif
+
+#define ERESTART        (ERROR_BASE_NO + 85)
+#define ESTRPIPE        (ERROR_BASE_NO + 86)
+#define EUSERS          (ERROR_BASE_NO + 87)
+#define ENOTSOCK        (ERROR_BASE_NO + 88)
+#define EDESTADDRREQ    (ERROR_BASE_NO + 89)
+#define EMSGSIZE        (ERROR_BASE_NO + 90)
+#define EPROTOTYPE      (ERROR_BASE_NO + 91)
+#define ENOPROTOOPT     (ERROR_BASE_NO + 92)
+#define EPROTONOSUPPORT (ERROR_BASE_NO + 93)
+#define ESOCKTNOSUPPORT (ERROR_BASE_NO + 94)
+#define EOPNOTSUPP      (ERROR_BASE_NO + 95)
+#define ENOTSUP         EOPNOTSUPP
+#define EPFNOSUPPORT    (ERROR_BASE_NO + 96)
+#define EAFNOSUPPORT    (ERROR_BASE_NO + 97)
+#define EADDRINUSE      (ERROR_BASE_NO + 98)
+#define EADDRNOTAVAIL   (ERROR_BASE_NO + 99)
+#define ENETDOWN        (ERROR_BASE_NO + 100)
+#define ENETUNREACH     (ERROR_BASE_NO + 101)
+#define ENETRESET       (ERROR_BASE_NO + 102)
+#define ECONNABORTED    (ERROR_BASE_NO + 103)
+#define ECONNRESET      (ERROR_BASE_NO + 104)
+#define ENOBUFS         (ERROR_BASE_NO + 105)
+#define EISCONN         (ERROR_BASE_NO + 106)
+#define ENOTCONN        (ERROR_BASE_NO + 107)
+#define ESHUTDOWN       (ERROR_BASE_NO + 108)
+#define ETOOMANYREFS    (ERROR_BASE_NO + 109)
+#define ETIMEDOUT       (ERROR_BASE_NO + 110)
+#define ECONNREFUSED    (ERROR_BASE_NO + 111)
+#define EHOSTDOWN       (ERROR_BASE_NO + 112)
+#define EHOSTUNREACH    (ERROR_BASE_NO + 113)
+#define EALREADY        (ERROR_BASE_NO + 114)
+#define EINPROGRESS     (ERROR_BASE_NO + 115)
+#define ESTALE          (ERROR_BASE_NO + 116)
+#define EUCLEAN         (ERROR_BASE_NO + 117)
+#define ENOTNAM         (ERROR_BASE_NO + 118)
+#define ENAVAIL         (ERROR_BASE_NO + 119)
+#define EISNAM          (ERROR_BASE_NO + 120)
+#define EREMOTEIO       (ERROR_BASE_NO + 121)
+#define EDQUOT          (ERROR_BASE_NO + 122)
+#define ENOMEDIUM       (ERROR_BASE_NO + 123)
+#define EMEDIUMTYPE     (ERROR_BASE_NO + 124)
+#define ECANCELED       (ERROR_BASE_NO + 125)
+#define ENOKEY          (ERROR_BASE_NO + 126)
+#define EKEYEXPIRED     (ERROR_BASE_NO + 127)
+#define EKEYREVOKED     (ERROR_BASE_NO + 128)
+#define EKEYREJECTED    (ERROR_BASE_NO + 129)
+#define EOWNERDEAD      (ERROR_BASE_NO + 130)
+#define ENOTRECOVERABLE (ERROR_BASE_NO + 131)
+#define ERFKILL         (ERROR_BASE_NO + 132)
+#define EHWPOISON       (ERROR_BASE_NO + 133)
+#endif
+
+#endif
diff --git a/components/libc/compilers/common/nogcc/sys/select.h b/components/libc/compilers/common/nogcc/sys/select.h
new file mode 100644
index 0000000000..575ad3a1b5
--- /dev/null
+++ b/components/libc/compilers/common/nogcc/sys/select.h
@@ -0,0 +1,52 @@
+/*
+ * Copyright (c) 2006-2021, RT-Thread Development Team
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Change Logs:
+ * Date           Author       Notes
+ * 2021-07-21     Meco Man     The first version
+ */
+
+#ifndef __SYS_SELECT_H__
+#define __SYS_SELECT_H__
+
+#include <rtconfig.h>
+#include <sys/types.h>
+#include <sys/time.h>
+
+#ifndef  FD_SETSIZE
+#define  FD_SETSIZE  32
+#endif
+
+#ifdef SAL_USING_POSIX
+#ifdef FD_SETSIZE
+#undef FD_SETSIZE
+#endif
+#define FD_SETSIZE      DFS_FD_MAX
+#endif /* SAL_USING_POSIX */
+
+#define   NBBY    8       /* number of bits in a byte */
+
+typedef long    fd_mask;
+
+#define   NFDBITS (sizeof (fd_mask) * NBBY)   /* bits per mask */
+#ifndef   howmany
+#define   howmany(x,y)    (((x)+((y)-1))/(y))
+#endif
+
+#ifndef _SYS_TYPES_FD_SET /* MIPS */
+typedef struct _types_fd_set {
+    fd_mask fds_bits[howmany(FD_SETSIZE, NFDBITS)];
+} _types_fd_set;
+#define fd_set _types_fd_set
+
+#define FD_SET(n, p)    ((p)->fds_bits[(n)/NFDBITS] |= (1L << ((n) % NFDBITS)))
+#define FD_CLR(n, p)    ((p)->fds_bits[(n)/NFDBITS] &= ~(1L << ((n) % NFDBITS)))
+#define FD_ISSET(n, p)  ((p)->fds_bits[(n)/NFDBITS] & (1L << ((n) % NFDBITS)))
+#define FD_ZERO(p)      memset((void*)(p), 0, sizeof(*(p)))
+#endif /* _SYS_TYPES_FD_SET */
+
+int select(int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, struct timeval *timeout);
+
+#endif /* __SYS_SELECT_H__ */
diff --git a/components/libc/compilers/common/nogcc/sys/stat.h b/components/libc/compilers/common/nogcc/sys/stat.h
new file mode 100644
index 0000000000..107c15decf
--- /dev/null
+++ b/components/libc/compilers/common/nogcc/sys/stat.h
@@ -0,0 +1,83 @@
+/*
+ * Copyright (c) 2006-2021, RT-Thread Development Team
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Change Logs:
+ * Date           Author       Notes
+ * 2021-09-02     Meco Man     First version
+ */
+
+#ifndef __SYS_STAT_H__
+#define __SYS_STAT_H__
+
+#include <sys/types.h>
+#include <sys/time.h>
+
+#define S_IFMT               00170000
+#define S_IFSOCK             0140000
+#define S_IFLNK              0120000
+#define S_IFREG              0100000
+#define S_IFBLK              0060000
+#define S_IFDIR              0040000
+#define S_IFCHR              0020000
+#define S_IFIFO              0010000
+#define S_ISUID              0004000
+#define S_ISGID              0002000
+#define S_ISVTX              0001000
+
+#define S_ISLNK(m)           (((m) & S_IFMT) == S_IFLNK)
+#define S_ISREG(m)           (((m) & S_IFMT) == S_IFREG)
+#define S_ISDIR(m)           (((m) & S_IFMT) == S_IFDIR)
+#define S_ISCHR(m)           (((m) & S_IFMT) == S_IFCHR)
+#define S_ISBLK(m)           (((m) & S_IFMT) == S_IFBLK)
+#define S_ISFIFO(m)          (((m) & S_IFMT) == S_IFIFO)
+#define S_ISSOCK(m)          (((m) & S_IFMT) == S_IFSOCK)
+
+#define S_IRWXU              00700
+#define S_IRUSR              00400
+#define S_IWUSR              00200
+#define S_IXUSR              00100
+
+#define S_IRWXG              00070
+#define S_IRGRP              00040
+#define S_IWGRP              00020
+#define S_IXGRP              00010
+
+#define S_IRWXO              00007
+#define S_IROTH              00004
+#define S_IWOTH              00002
+#define S_IXOTH              00001
+
+struct stat
+{
+    struct rt_device *st_dev;
+    uint16_t  st_ino;
+    uint16_t  st_mode;
+    uint16_t  st_nlink;
+    uint16_t  st_uid;
+    uint16_t  st_gid;
+    struct rt_device *st_rdev;
+    uint32_t  st_size;
+    time_t    st_atime;
+    long      st_spare1;
+    time_t    st_mtime;
+    long      st_spare2;
+    time_t    st_ctime;
+    long      st_spare3;
+    uint32_t  st_blksize;
+    uint32_t  st_blocks;
+    long      st_spare4[2];
+};
+
+int    chmod(const char *, mode_t);
+int    fchmod(int, mode_t);
+int    fstat(int, struct stat *);
+int    lstat(const char *, struct stat *);
+int    mkdir(const char *, mode_t);
+int    mkfifo(const char *, mode_t);
+int    mknod(const char *, mode_t, dev_t);
+int    stat(const char *, struct stat *);
+mode_t umask(mode_t);
+
+#endif
diff --git a/components/libc/compilers/common/nogcc/sys/types.h b/components/libc/compilers/common/nogcc/sys/types.h
new file mode 100644
index 0000000000..5672f54a4d
--- /dev/null
+++ b/components/libc/compilers/common/nogcc/sys/types.h
@@ -0,0 +1,39 @@
+/*
+ * Copyright (c) 2006-2021, RT-Thread Development Team
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Change Logs:
+ * Date           Author       Notes
+ * 2020-09-05     Meco Man     fix bugs
+ * 2020-12-16     Meco Man     add useconds_t
+ */
+#ifndef __SYS_TYPES_H__
+#define __SYS_TYPES_H__
+
+#include <stdint.h>
+#include <stddef.h>
+#include <time.h>
+
+typedef int32_t          clockid_t;
+typedef int32_t          key_t;         /* Used for interprocess communication. */
+typedef int              pid_t;         /* Used for process IDs and process group IDs. */
+typedef unsigned short   uid_t;
+typedef unsigned short   gid_t;
+typedef signed long      off_t;
+typedef int              mode_t;
+#ifndef ARCH_CPU_64BIT
+typedef signed int       ssize_t;       /* Used for a count of bytes or an error indication. */
+#else
+typedef long signed int  ssize_t;       /* Used for a count of bytes or an error indication. */
+#endif
+typedef long             suseconds_t;   /* microseconds. */
+typedef unsigned long    useconds_t;    /* microseconds (unsigned) */
+
+typedef unsigned long    dev_t;
+
+typedef unsigned int     u_int;
+typedef unsigned char    u_char;
+typedef unsigned long    u_long;
+
+#endif
diff --git a/components/libc/compilers/common/nogcc/sys/unistd.h b/components/libc/compilers/common/nogcc/sys/unistd.h
new file mode 100644
index 0000000000..6195c4c2aa
--- /dev/null
+++ b/components/libc/compilers/common/nogcc/sys/unistd.h
@@ -0,0 +1,45 @@
+/*
+ * Copyright (c) 2006-2021, RT-Thread Development Team
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Change Logs:
+ * Date           Author       Notes
+ * 2020-12-16     Meco Man     add usleep
+ * 2021-09-11     Meco Man     move functions from dfs_posix.h to unistd.h
+ */
+#ifndef __SYS_UNISTD_H__
+#define __SYS_UNISTD_H__
+
+#include <stddef.h>
+#include "types.h" /* <sys/types.h> */
+
+#define STDIN_FILENO    0       /* standard input file descriptor */
+#define STDOUT_FILENO   1       /* standard output file descriptor */
+#define STDERR_FILENO   2       /* standard error file descriptor */
+
+ssize_t read(int fd, void *buf, size_t len);
+ssize_t write(int fd, const void *buf, size_t len);
+off_t lseek(int fd, off_t offset, int whence);
+int fsync(int fildes);
+int unlink(const char *pathname);
+int close(int d);
+int ftruncate(int fd, off_t length);
+int rmdir(const char *path);
+int chdir(const char *path);
+char *getcwd(char *buf, size_t size);
+int access(const char *path, int amode);
+int pipe(int fildes[2]);
+int isatty(int fd);
+char *ttyname(int desc);
+unsigned int sleep(unsigned int seconds);
+int usleep(useconds_t usec);
+pid_t gettid(void);
+pid_t getpid(void);
+pid_t getppid(void);
+uid_t getuid(void);
+uid_t geteuid(void);
+gid_t getgid(void);
+gid_t getegid(void);
+
+#endif /* _SYS_UNISTD_H */
diff --git a/components/libc/compilers/common/nogcc/unistd.h b/components/libc/compilers/common/nogcc/unistd.h
new file mode 100644
index 0000000000..cd77a12e3b
--- /dev/null
+++ b/components/libc/compilers/common/nogcc/unistd.h
@@ -0,0 +1,10 @@
+/*
+ * Copyright (c) 2006-2021, RT-Thread Development Team
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Change Logs:
+ * Date           Author       Notes
+ */
+#include "sys/unistd.h"
+
diff --git a/components/libc/compilers/common/partial/SConscript b/components/libc/compilers/common/partial/SConscript
new file mode 100644
index 0000000000..4c815c49b8
--- /dev/null
+++ b/components/libc/compilers/common/partial/SConscript
@@ -0,0 +1,15 @@
+# RT-Thread building script for bridge
+
+import os
+from building import *
+
+cwd = GetCurrentDir()
+objs = []
+list = os.listdir(cwd)
+
+for d in list:
+    path = os.path.join(cwd, d)
+    if os.path.isfile(os.path.join(path, 'SConscript')):
+        objs = objs + SConscript(os.path.join(d, 'SConscript'))
+
+Return('objs')
diff --git a/components/libc/compilers/common/partial/ls/SConscript b/components/libc/compilers/common/partial/ls/SConscript
new file mode 100644
index 0000000000..2665bee078
--- /dev/null
+++ b/components/libc/compilers/common/partial/ls/SConscript
@@ -0,0 +1,23 @@
+from shutil import copy
+from building import *
+
+Import('rtconfig')
+
+src   = []
+cwd   = GetCurrentDir()
+CPPPATH = [cwd]
+group = []
+
+if rtconfig.PLATFORM == 'gcc' and GetDepend('SOC_LS'):
+    try:
+        # There is no 'sys/select.h' in these bsp's gcc toolchain; thus, we need to copy this file from 'nogcc/sys/select.h'
+        copy("../../nogcc/sys/select.h", "./sys/select.h")
+    except:
+        pass
+
+    if GetDepend('RT_USING_LIBC'):
+        src += Glob('*.c')
+
+    group = DefineGroup('libc', src, depend = [], CPPPATH = CPPPATH)
+
+Return('group')
diff --git a/components/libc/compilers/common/partial/ls/readme.md b/components/libc/compilers/common/partial/ls/readme.md
new file mode 100644
index 0000000000..fa68e1e84a
--- /dev/null
+++ b/components/libc/compilers/common/partial/ls/readme.md
@@ -0,0 +1,9 @@
+This folder will be included when compiling the BSPs as follow:
+
+- ls1bdev
+- ls1cdev
+- ls2kdev
+
+These files will be generated by scons automatically , and **DO NOT** change them:
+
+- sys/select.h
\ No newline at end of file
diff --git a/components/libc/compilers/common/partial/ls/sys/select.h b/components/libc/compilers/common/partial/ls/sys/select.h
new file mode 100644
index 0000000000..575ad3a1b5
--- /dev/null
+++ b/components/libc/compilers/common/partial/ls/sys/select.h
@@ -0,0 +1,52 @@
+/*
+ * Copyright (c) 2006-2021, RT-Thread Development Team
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Change Logs:
+ * Date           Author       Notes
+ * 2021-07-21     Meco Man     The first version
+ */
+
+#ifndef __SYS_SELECT_H__
+#define __SYS_SELECT_H__
+
+#include <rtconfig.h>
+#include <sys/types.h>
+#include <sys/time.h>
+
+#ifndef  FD_SETSIZE
+#define  FD_SETSIZE  32
+#endif
+
+#ifdef SAL_USING_POSIX
+#ifdef FD_SETSIZE
+#undef FD_SETSIZE
+#endif
+#define FD_SETSIZE      DFS_FD_MAX
+#endif /* SAL_USING_POSIX */
+
+#define   NBBY    8       /* number of bits in a byte */
+
+typedef long    fd_mask;
+
+#define   NFDBITS (sizeof (fd_mask) * NBBY)   /* bits per mask */
+#ifndef   howmany
+#define   howmany(x,y)    (((x)+((y)-1))/(y))
+#endif
+
+#ifndef _SYS_TYPES_FD_SET /* MIPS */
+typedef struct _types_fd_set {
+    fd_mask fds_bits[howmany(FD_SETSIZE, NFDBITS)];
+} _types_fd_set;
+#define fd_set _types_fd_set
+
+#define FD_SET(n, p)    ((p)->fds_bits[(n)/NFDBITS] |= (1L << ((n) % NFDBITS)))
+#define FD_CLR(n, p)    ((p)->fds_bits[(n)/NFDBITS] &= ~(1L << ((n) % NFDBITS)))
+#define FD_ISSET(n, p)  ((p)->fds_bits[(n)/NFDBITS] & (1L << ((n) % NFDBITS)))
+#define FD_ZERO(p)      memset((void*)(p), 0, sizeof(*(p)))
+#endif /* _SYS_TYPES_FD_SET */
+
+int select(int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, struct timeval *timeout);
+
+#endif /* __SYS_SELECT_H__ */
diff --git a/components/libc/compilers/common/poll.h b/components/libc/compilers/common/poll.h
new file mode 100644
index 0000000000..aea73d6eaf
--- /dev/null
+++ b/components/libc/compilers/common/poll.h
@@ -0,0 +1,49 @@
+/*
+ * Copyright (c) 2006-2021, RT-Thread Development Team
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Change Logs:
+ * Date           Author       Notes
+ * 2021-09-11     Meco Man     First version
+ */
+#ifndef __POLL_H__
+#define __POLL_H__
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#if !defined(POLLIN) && !defined(POLLOUT)
+#define POLLIN          (0x01)
+#define POLLRDNORM      (0x01)
+#define POLLRDBAND      (0x01)
+#define POLLPRI         (0x01)
+
+#define POLLOUT         (0x02)
+#define POLLWRNORM      (0x02)
+#define POLLWRBAND      (0x02)
+
+#define POLLERR         (0x04)
+#define POLLHUP         (0x08)
+#define POLLNVAL        (0x10)
+
+typedef unsigned int nfds_t;
+
+struct pollfd
+{
+    int fd;
+    short events;
+    short revents;
+};
+#endif /* !defined(POLLIN) && !defined(POLLOUT) */
+
+#define POLLMASK_DEFAULT (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM)
+
+int poll(struct pollfd *fds, nfds_t nfds, int timeout);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __POLL_H__ */
diff --git a/components/libc/compilers/common/readme.md b/components/libc/compilers/common/readme.md
index 99797d933c..856ddeb045 100644
--- a/components/libc/compilers/common/readme.md
+++ b/components/libc/compilers/common/readme.md
@@ -1,8 +1,8 @@
 ## Attentions
 
-1. This folder is "common" for armlibc newlibc and dlib. It's not "common" for minilibc.
+1. This folder is "common" for all toolchains.
 
-2. If you want to add new .c files, please do not forget to fix SConscript file too. eg:
+2. If you want to add new `.c` files, please do not forget to fix SConscript file too. eg:
 
 ```python
 if GetDepend('RT_USING_POSIX') == False:
diff --git a/components/libc/compilers/common/stdlib.c b/components/libc/compilers/common/stdlib.c
index 9f801ab966..16a13afb83 100644
--- a/components/libc/compilers/common/stdlib.c
+++ b/components/libc/compilers/common/stdlib.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2006-2018, RT-Thread Development Team
+ * Copyright (c) 2006-2021, RT-Thread Development Team
  *
  * SPDX-License-Identifier: Apache-2.0
  *
@@ -10,27 +10,26 @@
 
 #include <rtthread.h>
 
+#define DBG_TAG    "stdlib"
+#define DBG_LVL    DBG_INFO
+#include <rtdbg.h>
+
 void __rt_libc_exit(int status)
 {
     rt_thread_t self = rt_thread_self();
 
-#ifdef RT_USING_MODULE
-    if (dlmodule_self())
-    {
-        dlmodule_exit(status);
-    }
-#endif
-
     if (self != RT_NULL)
     {
-        rt_kprintf("thread:%s exit:%d!\n", self->name, status);
-        rt_thread_suspend(self);
-        rt_schedule();
+        LOG_E("thread:%s exit:%d!", self->name, status);
+        rt_thread_control(self, RT_THREAD_CTRL_CLOSE, RT_NULL);
     }
 }
 
 int __rt_libc_system(const char *string)
 {
-    /* TODO */
+#ifdef RT_USING_MSH
+    extern int msh_exec(char *cmd, rt_size_t length);
+    msh_exec((char*)string, rt_strlen(string));
+#endif
     return 0;
 }
diff --git a/components/libc/compilers/common/sys/ioctl.h b/components/libc/compilers/common/sys/ioctl.h
new file mode 100644
index 0000000000..b926a71875
--- /dev/null
+++ b/components/libc/compilers/common/sys/ioctl.h
@@ -0,0 +1,240 @@
+/*
+ * Copyright (c) 2006-2021, RT-Thread Development Team
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Change Logs:
+ * Date           Author       Notes
+ * 2020-09-01     Meco Man     First Version
+ */
+#ifndef _SYS_IOCTL_H
+#define _SYS_IOCTL_H
+
+#include <rtconfig.h>
+#ifdef RT_USING_POSIX
+#include <dfs_posix.h>
+#endif
+
+struct winsize {
+    unsigned short ws_row;
+    unsigned short ws_col;
+    unsigned short ws_xpixel;
+    unsigned short ws_ypixel;
+};
+
+#define _IOC(a,b,c,d) ( ((a)<<30) | ((b)<<8) | (c) | ((d)<<16) )
+#define _IOC_NONE  0U
+#define _IOC_WRITE 1U
+#define _IOC_READ  2U
+
+#if !defined (_WIN32) && !defined (__TASKING__)
+#define _IO(a,b)    _IOC(_IOC_NONE,(a),(b),0)
+#define _IOW(a,b,c) _IOC(_IOC_WRITE,(a),(b),sizeof(c))
+#define _IOR(a,b,c) _IOC(_IOC_READ,(a),(b),sizeof(c))
+#define _IOWR(a,b,c) _IOC(_IOC_READ|_IOC_WRITE,(a),(b),sizeof(c))
+
+#define FIONREAD    _IOR('f', 127, int) /* get # bytes to read */
+#define FIONBIO     _IOW('f', 126, int) /* set/clear non-blocking i/o */
+#define FIONWRITE   _IOR('f', 121, int) /* get # bytes outstanding in send queue */
+#endif
+
+#define TCGETS      0x5401
+#define TCSETS      0x5402
+#define TCSETSW     0x5403
+#define TCSETSF     0x5404
+#define TCGETA      0x5405
+#define TCSETA      0x5406
+#define TCSETAW     0x5407
+#define TCSETAF     0x5408
+#define TCSBRK      0x5409
+#define TCXONC      0x540A
+#define TCFLSH      0x540B
+#define TIOCEXCL    0x540C
+#define TIOCNXCL    0x540D
+#define TIOCSCTTY   0x540E
+#define TIOCGPGRP   0x540F
+#define TIOCSPGRP   0x5410
+#define TIOCOUTQ    0x5411
+#define TIOCSTI     0x5412
+#define TIOCGWINSZ  0x5413
+#define TIOCSWINSZ  0x5414
+#define TIOCMGET    0x5415
+#define TIOCMBIS    0x5416
+#define TIOCMBIC    0x5417
+#define TIOCMSET    0x5418
+#define TIOCGSOFTCAR    0x5419
+#define TIOCSSOFTCAR    0x541A
+#ifndef FIONREAD
+#define FIONREAD 0x541B
+#endif
+#define TIOCINQ     FIONREAD
+#define TIOCLINUX   0x541C
+#define TIOCCONS    0x541D
+#define TIOCGSERIAL 0x541E
+#define TIOCSSERIAL 0x541F
+#define TIOCPKT     0x5420
+#ifndef FIONBIO
+#define FIONBIO  0x5421
+#endif
+#define TIOCNOTTY   0x5422
+#define TIOCSETD    0x5423
+#define TIOCGETD    0x5424
+#define TCSBRKP     0x5425
+#define TIOCSBRK    0x5427
+#define TIOCCBRK    0x5428
+#define TIOCGSID    0x5429
+#define TIOCGRS485  0x542E
+#define TIOCSRS485  0x542F
+#define TIOCGPTN    0x80045430
+#define TIOCSPTLCK  0x40045431
+#define TIOCGDEV    0x80045432
+#define TCGETX      0x5432
+#define TCSETX      0x5433
+#define TCSETXF     0x5434
+#define TCSETXW     0x5435
+#define TIOCSIG     0x40045436
+#define TIOCVHANGUP 0x5437
+#define TIOCGPKT    0x80045438
+#define TIOCGPTLCK  0x80045439
+#define TIOCGEXCL   0x80045440
+
+#define FIONCLEX    0x5450
+#define FIOCLEX     0x5451
+
+#ifndef _WIN32
+#define FIOASYNC    0x5452
+#endif
+
+#define TIOCSERCONFIG   0x5453
+#define TIOCSERGWILD    0x5454
+#define TIOCSERSWILD    0x5455
+#define TIOCGLCKTRMIOS  0x5456
+#define TIOCSLCKTRMIOS  0x5457
+#define TIOCSERGSTRUCT  0x5458
+#define TIOCSERGETLSR   0x5459
+#define TIOCSERGETMULTI 0x545A
+#define TIOCSERSETMULTI 0x545B
+
+#define TIOCMIWAIT  0x545C
+#define TIOCGICOUNT 0x545D
+#define FIOQSIZE    0x5460
+
+#define TIOCPKT_DATA         0
+#define TIOCPKT_FLUSHREAD    1
+#define TIOCPKT_FLUSHWRITE   2
+#define TIOCPKT_STOP         4
+#define TIOCPKT_START        8
+#define TIOCPKT_NOSTOP      16
+#define TIOCPKT_DOSTOP      32
+#define TIOCPKT_IOCTL       64
+
+#define TIOCSER_TEMT    0x01
+
+#define TIOCM_LE        0x001
+#define TIOCM_DTR       0x002
+#define TIOCM_RTS       0x004
+#define TIOCM_ST        0x008
+#define TIOCM_SR        0x010
+#define TIOCM_CTS       0x020
+#define TIOCM_CAR       0x040
+#define TIOCM_RNG       0x080
+#define TIOCM_DSR       0x100
+#define TIOCM_CD        TIOCM_CAR
+#define TIOCM_RI        TIOCM_RNG
+#define TIOCM_OUT1      0x2000
+#define TIOCM_OUT2      0x4000
+#define TIOCM_LOOP      0x8000
+
+#define N_TTY           0
+#define N_SLIP          1
+#define N_MOUSE         2
+#define N_PPP           3
+#define N_STRIP         4
+#define N_AX25          5
+#define N_X25           6
+#define N_6PACK         7
+#define N_MASC          8
+#define N_R3964         9
+#define N_PROFIBUS_FDL  10
+#define N_IRDA          11
+#define N_SMSBLOCK      12
+#define N_HDLC          13
+#define N_SYNC_PPP      14
+#define N_HCI           15
+
+#define FIOSETOWN       0x8901
+#define SIOCSPGRP       0x8902
+#define FIOGETOWN       0x8903
+#define SIOCGPGRP       0x8904
+#ifndef SIOCATMARK
+#define SIOCATMARK      0x8905
+#endif
+#define SIOCGSTAMP      0x8906
+#define SIOCGSTAMPNS    0x8907
+
+#define SIOCADDRT       0x890B
+#define SIOCDELRT       0x890C
+#define SIOCRTMSG       0x890D
+
+#define SIOCGIFNAME     0x8910
+#define SIOCSIFLINK     0x8911
+#define SIOCGIFCONF     0x8912
+#define SIOCGIFFLAGS    0x8913
+#define SIOCSIFFLAGS    0x8914
+#define SIOCGIFADDR     0x8915
+#define SIOCSIFADDR     0x8916
+#define SIOCGIFDSTADDR  0x8917
+#define SIOCSIFDSTADDR  0x8918
+#define SIOCGIFBRDADDR  0x8919
+#define SIOCSIFBRDADDR  0x891a
+#define SIOCGIFNETMASK  0x891b
+#define SIOCSIFNETMASK  0x891c
+#define SIOCGIFMETRIC   0x891d
+#define SIOCSIFMETRIC   0x891e
+#define SIOCGIFMEM      0x891f
+#define SIOCSIFMEM      0x8920
+#define SIOCGIFMTU      0x8921
+#define SIOCSIFMTU      0x8922
+#define SIOCSIFNAME     0x8923
+#define SIOCSIFHWADDR   0x8924
+#define SIOCGIFENCAP    0x8925
+#define SIOCSIFENCAP    0x8926
+#define SIOCGIFHWADDR   0x8927
+#define SIOCGIFSLAVE    0x8929
+#define SIOCSIFSLAVE    0x8930
+#define SIOCADDMULTI    0x8931
+#define SIOCDELMULTI    0x8932
+#define SIOCGIFINDEX    0x8933
+#define SIOGIFINDEX     SIOCGIFINDEX
+#define SIOCSIFPFLAGS   0x8934
+#define SIOCGIFPFLAGS   0x8935
+#define SIOCDIFADDR     0x8936
+#define SIOCSIFHWBROADCAST 0x8937
+#define SIOCGIFCOUNT    0x8938
+
+#define SIOCGIFBR       0x8940
+#define SIOCSIFBR       0x8941
+
+#define SIOCGIFTXQLEN   0x8942
+#define SIOCSIFTXQLEN   0x8943
+
+#define SIOCDARP        0x8953
+#define SIOCGARP        0x8954
+#define SIOCSARP        0x8955
+
+#define SIOCDRARP       0x8960
+#define SIOCGRARP       0x8961
+#define SIOCSRARP       0x8962
+
+#define SIOCGIFMAP      0x8970
+#define SIOCSIFMAP      0x8971
+
+#define SIOCADDDLCI     0x8980
+#define SIOCDELDLCI     0x8981
+
+#define SIOCDEVPRIVATE      0x89F0
+#define SIOCPROTOPRIVATE    0x89E0
+
+int ioctl(int fildes, int cmd, ...);
+
+#endif
diff --git a/components/libc/compilers/common/sys/mman.h b/components/libc/compilers/common/sys/mman.h
new file mode 100644
index 0000000000..2da2ddf716
--- /dev/null
+++ b/components/libc/compilers/common/sys/mman.h
@@ -0,0 +1,60 @@
+/*
+ * Copyright (c) 2006-2021, RT-Thread Development Team
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Change Logs:
+ * Date           Author       Notes
+ * 2017/11/30     Bernard      The first version.
+ */
+
+#ifndef _SYS_MMAN_H
+#define _SYS_MMAN_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <sys/types.h>
+
+#define MAP_FAILED     ((void *) -1)
+
+#define MAP_SHARED     0x01
+#define MAP_PRIVATE    0x02
+#define MAP_TYPE       0x0f
+#define MAP_FIXED      0x10
+#define MAP_ANON       0x20
+#define MAP_ANONYMOUS  MAP_ANON
+#define MAP_NORESERVE  0x4000
+#define MAP_GROWSDOWN  0x0100
+#define MAP_DENYWRITE  0x0800
+#define MAP_EXECUTABLE 0x1000
+#define MAP_LOCKED     0x2000
+#define MAP_POPULATE   0x8000
+#define MAP_NONBLOCK   0x10000
+#define MAP_STACK      0x20000
+#define MAP_HUGETLB    0x40000
+#define MAP_FILE       0
+
+#define PROT_NONE      0
+#define PROT_READ      1
+#define PROT_WRITE     2
+#define PROT_EXEC      4
+#define PROT_GROWSDOWN 0x01000000
+#define PROT_GROWSUP   0x02000000
+
+#define MS_ASYNC       1
+#define MS_INVALIDATE  2
+#define MS_SYNC        4
+
+#define MCL_CURRENT    1
+#define MCL_FUTURE     2
+#define MCL_ONFAULT    4
+
+void *mmap (void *start, size_t len, int prot, int flags, int fd, off_t off);
+int munmap (void *start, size_t len);
+
+#ifdef __cplusplus
+}
+#endif
+#endif
diff --git a/components/libc/compilers/common/sys/signal.h b/components/libc/compilers/common/sys/signal.h
new file mode 100644
index 0000000000..9787958a37
--- /dev/null
+++ b/components/libc/compilers/common/sys/signal.h
@@ -0,0 +1,194 @@
+/*
+ * Copyright (c) 2006-2021, RT-Thread Development Team
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Change Logs:
+ * Date           Author       Notes
+ * 2017-09-12     Bernard      The first version
+ * 2021-07-21     Meco Man     move to libc/common
+ */
+
+#ifndef __SYS_SIGNAL_H__
+#define __SYS_SIGNAL_H__
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stdint.h>
+
+/*  Signal Generation and Delivery, P1003.1b-1993, p. 63
+    NOTE: P1003.1c/D10, p. 34 adds sigev_notify_function and
+          sigev_notify_attributes to the sigevent structure.  */
+union sigval
+{
+    int    sival_int;    /* Integer signal value */
+    void  *sival_ptr;    /* Pointer signal value */
+};
+
+struct sigevent
+{
+    int          sigev_notify;               /* Notification type */
+    int          sigev_signo;                /* Signal number */
+    union sigval sigev_value;                /* Signal value */
+    void         (*sigev_notify_function)( union sigval );
+                                             /* Notification function */
+    void         *sigev_notify_attributes;   /* Notification Attributes, really pthread_attr_t */
+};
+
+struct siginfo
+{
+    uint16_t si_signo;
+    uint16_t si_code;
+
+    union sigval si_value;
+};
+typedef struct siginfo siginfo_t;
+
+#define SI_USER     0x01    /* Signal sent by kill(). */
+#define SI_QUEUE    0x02    /* Signal sent by sigqueue(). */
+#define SI_TIMER    0x03    /* Signal generated by expiration of a timer set by timer_settime(). */
+#define SI_ASYNCIO  0x04    /* Signal generated by completion of an asynchronous I/O request. */
+#define SI_MESGQ    0x05    /* Signal generated by arrival of a message on an empty message queue. */
+
+typedef void (*_sig_func_ptr)(int);
+typedef unsigned long sigset_t;
+
+struct sigaction
+{
+    _sig_func_ptr sa_handler;
+    sigset_t sa_mask;
+    int sa_flags;
+};
+
+#define SIG_SETMASK 0   /* set mask with sigprocmask() */
+#define SIG_BLOCK   1   /* set of signals to block */
+#define SIG_UNBLOCK 2   /* set of signals to, well, unblock */
+
+#define sigaddset(what,sig) (*(what) |= (1<<(sig)), 0)
+#define sigdelset(what,sig) (*(what) &= ~(1<<(sig)), 0)
+#define sigemptyset(what)   (*(what) = 0, 0)
+#define sigfillset(what)    (*(what) = ~(0), 0)
+#define sigismember(what,sig) (((*(what)) & (1<<(sig))) != 0)
+
+int sigprocmask (int how, const sigset_t *set, sigset_t *oset);
+int sigaction(int signum, const struct sigaction *act, struct sigaction *oldact);
+
+#ifdef __ARMCC_VERSION
+#define SIGHUP       1
+/* #define SIGINT       2 */
+#define SIGQUIT      3
+/* #define SIGILL       4 */
+#define SIGTRAP      5
+/* #define SIGABRT      6 */
+#define SIGEMT       7
+/* #define SIGFPE       8 */
+#define SIGKILL      9
+#define SIGBUS      10
+/* #define SIGSEGV     11 */
+#define SIGSYS      12
+#define SIGPIPE     13
+#define SIGALRM     14
+/* #define SIGTERM     15 */
+#define SIGURG      16
+#define SIGSTOP     17
+#define SIGTSTP     18
+#define SIGCONT     19
+#define SIGCHLD     20
+#define SIGTTIN     21
+#define SIGTTOU     22
+#define SIGPOLL     23
+#define SIGWINCH    24
+/* #define SIGUSR1     25 */
+/* #define SIGUSR2     26 */
+#define SIGRTMIN    27
+#define SIGRTMAX    31
+#define NSIG        32
+
+#include <signal.h>
+
+#elif defined(__IAR_SYSTEMS_ICC__)
+#define SIGHUP       1
+#define SIGINT       2
+#define SIGQUIT      3
+#define SIGILL       4
+#define SIGTRAP      5
+/* #define SIGABRT      6 */
+#define SIGEMT       7
+#define SIGFPE       8
+#define SIGKILL      9
+#define SIGBUS      10
+#define SIGSEGV     11
+#define SIGSYS      12
+#define SIGPIPE     13
+#define SIGALRM     14
+#define SIGTERM     15
+#define SIGURG      16
+#define SIGSTOP     17
+#define SIGTSTP     18
+#define SIGCONT     19
+#define SIGCHLD     20
+#define SIGTTIN     21
+#define SIGTTOU     22
+#define SIGPOLL     23
+#define SIGWINCH    24
+#define SIGUSR1     25
+#define SIGUSR2     26
+#define SIGRTMIN    27
+#define SIGRTMAX    31
+#define NSIG        32
+
+#include <signal.h>
+
+#elif defined(__GNUC__)
+#define SIGHUP  1   /* hangup */
+#define SIGINT  2   /* interrupt */
+#define SIGQUIT 3   /* quit */
+#define SIGILL  4   /* illegal instruction (not reset when caught) */
+#define SIGTRAP 5   /* trace trap (not reset when caught) */
+#define SIGIOT  6   /* IOT instruction */
+#define SIGABRT 6   /* used by abort, replace SIGIOT in the future */
+#define SIGEMT  7   /* EMT instruction */
+#define SIGFPE  8   /* floating point exception */
+#define SIGKILL 9   /* kill (cannot be caught or ignored) */
+#define SIGBUS  10  /* bus error */
+#define SIGSEGV 11  /* segmentation violation */
+#define SIGSYS  12  /* bad argument to system call */
+#define SIGPIPE 13  /* write on a pipe with no one to read it */
+#define SIGALRM 14  /* alarm clock */
+#define SIGTERM 15  /* software termination signal from kill */
+#define SIGURG  16  /* urgent condition on IO channel */
+#define SIGSTOP 17  /* sendable stop signal not from tty */
+#define SIGTSTP 18  /* stop signal from tty */
+#define SIGCONT 19  /* continue a stopped process */
+#define SIGCHLD 20  /* to parent on child stop or exit */
+#define SIGCLD  20  /* System V name for SIGCHLD */
+#define SIGTTIN 21  /* to readers pgrp upon background tty read */
+#define SIGTTOU 22  /* like TTIN for output if (tp->t_local&LTOSTOP) */
+#define SIGIO   23  /* input/output possible signal */
+#define SIGPOLL SIGIO   /* System V name for SIGIO */
+#define SIGXCPU 24  /* exceeded CPU time limit */
+#define SIGXFSZ 25  /* exceeded file size limit */
+#define SIGVTALRM 26    /* virtual time alarm */
+#define SIGPROF 27  /* profiling time alarm */
+#define SIGWINCH 28 /* window changed */
+#define SIGLOST 29  /* resource lost (eg, record-lock lost) */
+#define SIGUSR1 30  /* user defined signal 1 */
+#define SIGUSR2 31  /* user defined signal 2 */
+#define NSIG    32      /* signal 0 implied */
+
+#ifndef _SIGNAL_H_
+/* Some applications take advantage of the fact that <sys/signal.h>
+ * and <signal.h> are equivalent in glibc.  Allow for that here.  */
+#include <signal.h>
+#endif
+
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
+
diff --git a/components/libc/compilers/common/sys/statfs.h b/components/libc/compilers/common/sys/statfs.h
new file mode 100644
index 0000000000..0c6dc44df3
--- /dev/null
+++ b/components/libc/compilers/common/sys/statfs.h
@@ -0,0 +1,24 @@
+/*
+ * Copyright (c) 2006-2021, RT-Thread Development Team
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Change Logs:
+ * Date           Author       Notes
+ */
+#ifndef __SYS_STATFS_H__
+#define __SYS_STATFS_H__
+
+#include <stddef.h>
+
+struct statfs
+{
+    size_t f_bsize;   /* block size */
+    size_t f_blocks;  /* total data blocks in file system */
+    size_t f_bfree;   /* free blocks in file system */
+};
+
+int statfs(const char *path, struct statfs *buf);
+int fstatfs(int fd, struct statfs *buf);
+
+#endif
diff --git a/components/libc/compilers/common/sys/termios.h b/components/libc/compilers/common/sys/termios.h
new file mode 100644
index 0000000000..c4b42083c4
--- /dev/null
+++ b/components/libc/compilers/common/sys/termios.h
@@ -0,0 +1,8 @@
+/*
+ * Copyright (c) 2006-2021, RT-Thread Development Team
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Change Logs:
+ * Date           Author       Notes
+ */
diff --git a/components/libc/compilers/common/sys/time.h b/components/libc/compilers/common/sys/time.h
index e4d60d2d11..d14905ebfb 100644
--- a/components/libc/compilers/common/sys/time.h
+++ b/components/libc/compilers/common/sys/time.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2006-2018, RT-Thread Development Team
+ * Copyright (c) 2006-2021, RT-Thread Development Team
  *
  * SPDX-License-Identifier: Apache-2.0
  *
@@ -8,56 +8,72 @@
  * 2020-09-07     Meco Man     combine gcc armcc iccarm
  * 2021-02-12     Meco Man     move all definitions located in <clock_time.h> to this file
  */
-#ifndef _SYS_TIME_H_
-#define _SYS_TIME_H_
+#ifndef __SYS_TIME_H__
+#define __SYS_TIME_H__
 
 #include <rtconfig.h>
+#include <sys/types.h>
+#include <stdint.h>
 #include <time.h>
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
-/*
- * Skip define timespec for IAR version over 8.10.1 where __VER__ is 8010001.
- */
-#if defined ( __ICCARM__ ) && (__VER__ >= 8010001)
-#define _TIMESPEC_DEFINED
-#endif
+/* timezone */
+#define DST_NONE    0   /* not on dst */
+#define DST_USA     1   /* USA style dst */
+#define DST_AUST    2   /* Australian style dst */
+#define DST_WET     3   /* Western European dst */
+#define DST_MET     4   /* Middle European dst */
+#define DST_EET     5   /* Eastern European dst */
+#define DST_CAN     6   /* Canada */
+#define DST_GB      7   /* Great Britain and Eire */
+#define DST_RUM     8   /* Rumania */
+#define DST_TUR     9   /* Turkey */
+#define DST_AUSTALT 10  /* Australian style with shift in 1986 */
 
+struct timezone
+{
+    int tz_minuteswest;   /* minutes west of Greenwich */
+    int tz_dsttime;       /* type of dst correction */
+};
 
-#ifndef _TIMEVAL_DEFINED
-#define _TIMEVAL_DEFINED
 /*
  * Structure returned by gettimeofday(2) system call,
  * and used in other calls.
  */
-struct timeval {
-    long    tv_sec;     /* seconds */
-    long    tv_usec;    /* and microseconds */
+#ifndef _TIMEVAL_DEFINED
+#define _TIMEVAL_DEFINED
+#if !defined(_WIN32)
+struct timeval
+{
+    time_t      tv_sec;     /* seconds */
+    suseconds_t tv_usec;    /* and microseconds */
 };
+#endif
 #endif /* _TIMEVAL_DEFINED */
 
-#if !defined __GNUC__ && !defined __ICCARM__
-struct timespec {
+#if !(defined(__GNUC__) && !defined(__ARMCC_VERSION)/*GCC*/) && \
+    !(defined(__ICCARM__) && (__VER__ >= 8010001)) && \
+    !defined(_WIN32)
+struct timespec
+{
     time_t  tv_sec;     /* seconds */
     long    tv_nsec;    /* and nanoseconds */
 };
 #endif
 
-struct timezone {
-  int tz_minuteswest;   /* minutes west of Greenwich */
-  int tz_dsttime;       /* type of dst correction */
-};
-
 int stime(const time_t *t);
 time_t timegm(struct tm * const t);
 int gettimeofday(struct timeval *tv, struct timezone *tz);
 int settimeofday(const struct timeval *tv, const struct timezone *tz);
+#if defined(__ARMCC_VERSION) || defined (__ICCARM__)
+struct tm *gmtime_r(const time_t *timep, struct tm *r);
+#endif
 
 #ifdef RT_USING_POSIX
-#include <sys/types.h>
-/* posix clock and timer */
+/* POSIX clock and timer */
 #define MILLISECOND_PER_SECOND  1000UL
 #define MICROSECOND_PER_SECOND  1000000UL
 #define NANOSECOND_PER_SECOND   1000000000UL
@@ -86,9 +102,13 @@ int settimeofday(const struct timeval *tv, const struct timezone *tz);
 int clock_getres  (clockid_t clockid, struct timespec *res);
 int clock_gettime (clockid_t clockid, struct timespec *tp);
 int clock_settime (clockid_t clockid, const struct timespec *tp);
-int clock_time_to_tick(const struct timespec *time);
+int rt_timespec_to_tick(const struct timespec *time);
 #endif /* RT_USING_POSIX */
 
+void tz_set(int8_t tz);
+int8_t tz_get(void);
+int8_t tz_is_dst(void);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/components/libc/compilers/common/sys/vfs.h b/components/libc/compilers/common/sys/vfs.h
new file mode 100644
index 0000000000..00739ab1c6
--- /dev/null
+++ b/components/libc/compilers/common/sys/vfs.h
@@ -0,0 +1,15 @@
+/*
+ * Copyright (c) 2006-2021, RT-Thread Development Team
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Change Logs:
+ * Date           Author       Notes
+ * 2021-09-11     Meco Man     First version
+ */
+#ifndef __SYS_VFS_H__
+#define __SYS_VFS_H__
+
+#include "statfs.h" /* <sys/statfs.h> */
+
+#endif
diff --git a/components/libc/compilers/common/termios.h b/components/libc/compilers/common/termios.h
index 414d0c0cb3..2960d52c58 100644
--- a/components/libc/compilers/common/termios.h
+++ b/components/libc/compilers/common/termios.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2006-2018, RT-Thread Development Team
+ * Copyright (c) 2006-2021, RT-Thread Development Team
  *
  * SPDX-License-Identifier: Apache-2.0
  *
diff --git a/components/libc/compilers/common/time.c b/components/libc/compilers/common/time.c
index c2fbd6f333..f81844f8e9 100644
--- a/components/libc/compilers/common/time.c
+++ b/components/libc/compilers/common/time.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2006-2018, RT-Thread Development Team
+ * Copyright (c) 2006-2021, RT-Thread Development Team
  *
  * SPDX-License-Identifier: Apache-2.0
  *
@@ -12,19 +12,27 @@
  * 2021-02-08     Meco Man     add settimeofday() stime()
  * 2021-02-10     Meco Man     add ctime_r() and re-implement ctime()
  * 2021-02-11     Meco Man     fix bug #3183 - align days[] and months[] to 4 bytes
- *                             add difftime()
  * 2021-02-12     Meco Man     add errno
  * 2012-12-08     Bernard      <clock_time.c> fix the issue of _timevalue.tv_usec initialization,
  *                             which found by Rob <[email protected]>
  * 2021-02-12     Meco Man     move all of the functions located in <clock_time.c> to this file
+ * 2021-03-15     Meco Man     fixed a bug of leaking memory in asctime()
+ * 2021-05-01     Meco Man     support fixed timezone
+ * 2021-07-21     Meco Man     implement that change/set timezone APIs
  */
 
-#include <sys/time.h>
+#include "sys/time.h"
+#include <sys/errno.h>
 #include <rtthread.h>
+#include <rthw.h>
 #ifdef RT_USING_DEVICE
 #include <rtdevice.h>
 #endif
 
+#define DBG_TAG    "time"
+#define DBG_LVL    DBG_INFO
+#include <rtdbg.h>
+
 /* seconds per day */
 #define SPD 24*60*60
 
@@ -63,6 +71,100 @@ static void num2str(char *c, int i)
     c[1] = i % 10 + '0';
 }
 
+/**
+ * Get time from RTC device (without timezone, UTC+0)
+ * @param tv: struct timeval
+ * @return the operation status, RT_EOK on successful
+ */
+static rt_err_t get_timeval(struct timeval *tv)
+{
+#ifdef RT_USING_RTC
+    static rt_device_t device = RT_NULL;
+    rt_err_t rst = -RT_ERROR;
+
+    if (tv == RT_NULL)
+        return -RT_EINVAL;
+
+    /* default is 0 */
+    tv->tv_sec = 0;
+    tv->tv_usec = 0;
+
+    /* optimization: find rtc device only first */
+    if (device == RT_NULL)
+    {
+        device = rt_device_find("rtc");
+    }
+
+    /* read timestamp from RTC device */
+    if (device != RT_NULL)
+    {
+        if (rt_device_open(device, 0) == RT_EOK)
+        {
+            rst = rt_device_control(device, RT_DEVICE_CTRL_RTC_GET_TIME, &tv->tv_sec);
+            rt_device_control(device, RT_DEVICE_CTRL_RTC_GET_TIME_US, &tv->tv_usec);
+            rt_device_close(device);
+        }
+    }
+    else
+    {
+        /* LOG_W will cause a recursive printing if ulog timestamp function is enabled */
+        rt_kprintf("Cannot find a RTC device to provide time!\r\n");
+        return -RT_ENOSYS;
+    }
+
+    return rst;
+
+#else
+    /* LOG_W will cause a recursive printing if ulog timestamp function is enabled */
+    rt_kprintf("Cannot find a RTC device to provide time!\r\n");
+    return -RT_ENOSYS;
+#endif /* RT_USING_RTC */
+}
+
+/**
+ * Set time to RTC device (without timezone)
+ * @param tv: struct timeval
+ * @return the operation status, RT_EOK on successful
+ */
+static int set_timeval(struct timeval *tv)
+{
+#ifdef RT_USING_RTC
+    static rt_device_t device = RT_NULL;
+    rt_err_t rst = -RT_ERROR;
+
+    if (tv == RT_NULL)
+        return -RT_EINVAL;
+
+    /* optimization: find rtc device only first */
+    if (device == RT_NULL)
+    {
+        device = rt_device_find("rtc");
+    }
+
+    /* read timestamp from RTC device */
+    if (device != RT_NULL)
+    {
+        if (rt_device_open(device, 0) == RT_EOK)
+        {
+            rst = rt_device_control(device, RT_DEVICE_CTRL_RTC_SET_TIME, &tv->tv_sec);
+            rt_device_control(device, RT_DEVICE_CTRL_RTC_SET_TIME_US, &tv->tv_usec);
+            rt_device_close(device);
+        }
+    }
+    else
+    {
+        LOG_W("Cannot find a RTC device to provide time!");
+        return -RT_ENOSYS;
+    }
+
+    return rst;
+
+#else
+    LOG_W("Cannot find a RTC device to provide time!");
+    return -RT_ENOSYS;
+#endif /* RT_USING_RTC */
+}
+
 struct tm *gmtime_r(const time_t *timep, struct tm *r)
 {
     time_t i;
@@ -97,7 +199,7 @@ struct tm *gmtime_r(const time_t *timep, struct tm *r)
     r->tm_mon = i;
     r->tm_mday += work - __spm[i];
 
-    r->tm_isdst = 0;
+    r->tm_isdst = tz_is_dst();
     return r;
 }
 RTM_EXPORT(gmtime_r);
@@ -109,14 +211,11 @@ struct tm* gmtime(const time_t* t)
 }
 RTM_EXPORT(gmtime);
 
-/*TODO: timezone */
 struct tm* localtime_r(const time_t* t, struct tm* r)
 {
     time_t local_tz;
-    int utc_plus;
 
-    utc_plus = 0; /* GTM: UTC+0 */
-    local_tz = *t + utc_plus * 3600;
+    local_tz = *t + tz_get() * 3600;
     return gmtime_r(&local_tz, r);
 }
 RTM_EXPORT(localtime_r);
@@ -128,15 +227,41 @@ struct tm* localtime(const time_t* t)
 }
 RTM_EXPORT(localtime);
 
-/* TODO: timezone */
 time_t mktime(struct tm * const t)
 {
-    return timegm(t);
+    time_t timestamp;
+
+    timestamp = timegm(t);
+    timestamp = timestamp - 3600 * tz_get();
+    return timestamp;
 }
 RTM_EXPORT(mktime);
 
 char* asctime_r(const struct tm *t, char *buf)
 {
+    /* Checking input validity */
+    if (rt_strlen(days) <= (t->tm_wday << 2) || rt_strlen(months) <= (t->tm_mon << 2))
+    {
+        LOG_W("asctime_r: the input parameters exceeded the limit, please check it.");
+        *(int*) buf = *(int*) days;
+        *(int*) (buf + 4) = *(int*) months;
+        num2str(buf + 8, t->tm_mday);
+        if (buf[8] == '0')
+            buf[8] = ' ';
+        buf[10] = ' ';
+        num2str(buf + 11, t->tm_hour);
+        buf[13] = ':';
+        num2str(buf + 14, t->tm_min);
+        buf[16] = ':';
+        num2str(buf + 17, t->tm_sec);
+        buf[19] = ' ';
+        num2str(buf + 20, 2000 / 100);
+        num2str(buf + 22, 2000 % 100);
+        buf[24] = '\n';
+        buf[25] = '\0';
+        return buf;
+    }
+
     /* "Wed Jun 30 21:49:08 1993\n" */
     *(int*) buf = *(int*) (days + (t->tm_wday << 2));
     *(int*) (buf + 4) = *(int*) (months + (t->tm_mon << 2));
@@ -153,81 +278,57 @@ char* asctime_r(const struct tm *t, char *buf)
     num2str(buf + 20, (t->tm_year + 1900) / 100);
     num2str(buf + 22, (t->tm_year + 1900) % 100);
     buf[24] = '\n';
+    buf[25] = '\0';
     return buf;
 }
 RTM_EXPORT(asctime_r);
 
 char* asctime(const struct tm *timeptr)
 {
-    static char buf[25];
+    static char buf[26];
     return asctime_r(timeptr, buf);
 }
 RTM_EXPORT(asctime);
 
-char *ctime_r (const time_t * tim_p, char * result)
+char *ctime_r(const time_t * tim_p, char * result)
 {
     struct tm tm;
-    return asctime_r (localtime_r (tim_p, &tm), result);
+    return asctime_r(localtime_r(tim_p, &tm), result);
 }
 RTM_EXPORT(ctime_r);
 
 char* ctime(const time_t *tim_p)
 {
-    return asctime (localtime (tim_p));
+    return asctime(localtime(tim_p));
 }
 RTM_EXPORT(ctime);
 
-double difftime (time_t tim1, time_t tim2)
-{
-    return (double)(tim1 - tim2);
-}
-RTM_EXPORT(difftime);
-
 /**
  * Returns the current time.
  *
  * @param time_t * t the timestamp pointer, if not used, keep NULL.
  *
- * @return The value ((time_t)-1) is returned if the calendar time is not available. 
+ * @return The value ((time_t)-1) is returned if the calendar time is not available.
  *         If timer is not a NULL pointer, the return value is also stored in timer.
  *
  */
 RT_WEAK time_t time(time_t *t)
 {
-    time_t time_now = ((time_t)-1); /* default is not available */
+    struct timeval now;
 
-#ifdef RT_USING_RTC
-    static rt_device_t device = RT_NULL;
-
-    /* optimization: find rtc device only first */
-    if (device == RT_NULL)
-    {
-        device = rt_device_find("rtc");
-    }
-
-    /* read timestamp from RTC device */
-    if (device != RT_NULL)
+    if(get_timeval(&now) == RT_EOK)
     {
-        if (rt_device_open(device, 0) == RT_EOK)
+        if (t)
         {
-            rt_device_control(device, RT_DEVICE_CTRL_RTC_GET_TIME, &time_now);
-            rt_device_close(device);
+            *t = now.tv_sec;
         }
+        return now.tv_sec;
     }
-#endif /* RT_USING_RTC */
-
-    /* if t is not NULL, write timestamp to *t */
-    if (t != RT_NULL)
-    {
-        *t = time_now;
-    }
-
-    if(time_now == (time_t)-1)
+    else
     {
-        errno = ENOSYS;
+        rt_set_errno(EFAULT);
+        return ((time_t)-1);
     }
-
-    return time_now;
 }
 RTM_EXPORT(time);
 
@@ -239,27 +340,24 @@ RTM_EXPORT(clock);
 
 int stime(const time_t *t)
 {
-#ifdef RT_USING_RTC
-    rt_device_t device;
+    struct timeval tv;
 
-    /* read timestamp from RTC device. */
-    device = rt_device_find("rtc");
-    if (rt_device_open(device, 0) == RT_EOK)
+    if (!t)
     {
-        rt_device_control(device, RT_DEVICE_CTRL_RTC_SET_TIME, (void*)t);
-        rt_device_close(device);
+        rt_set_errno(EFAULT);
+        return -1;
+    }
+
+    tv.tv_sec = *t;
+    if (set_timeval(&tv) == RT_EOK)
+    {
+        return 0;
     }
     else
     {
-        errno = ENOSYS;
+        rt_set_errno(EFAULT);
         return -1;
     }
-    return 0;
-
-#else
-    errno = ENOSYS;
-    return -1;
-#endif /* RT_USING_RTC */
 }
 RTM_EXPORT(stime);
 
@@ -338,68 +436,98 @@ time_t timegm(struct tm * const t)
 }
 RTM_EXPORT(timegm);
 
-/* TODO: timezone */
 int gettimeofday(struct timeval *tv, struct timezone *tz)
 {
-    time_t t = time(RT_NULL);
+    /* The use of the timezone structure is obsolete;
+     * the tz argument should normally be specified as NULL.
+     * The tz_dsttime field has never been used under Linux.
+     * Thus, the following is purely of historic interest.
+     */
+    if(tz != RT_NULL)
+    {
+        tz->tz_dsttime = DST_NONE;
+        tz->tz_minuteswest = -(tz_get() * 60);
+    }
 
-    if (tv != RT_NULL && t != (time_t)-1)
+    if (tv != RT_NULL && get_timeval(tv) == RT_EOK)
     {
-        tv->tv_sec = t;
-        tv->tv_usec = 0;
         return 0;
     }
     else
     {
-        errno = ENOSYS;
+        rt_set_errno(EFAULT);
         return -1;
     }
 }
 RTM_EXPORT(gettimeofday);
 
-/* TODO: timezone */
 int settimeofday(const struct timeval *tv, const struct timezone *tz)
 {
-    if (tv != RT_NULL)
+    /* The use of the timezone structure is obsolete;
+     * the tz argument should normally be specified as NULL.
+     * The tz_dsttime field has never been used under Linux.
+     * Thus, the following is purely of historic interest.
+     */
+    if (tv != RT_NULL
+        && tv->tv_usec >= 0
+        && set_timeval((struct timeval *)tv) == RT_EOK)
     {
-        return stime((const time_t *)&tv->tv_sec);
+        return 0;
     }
     else
     {
-        errno = ENOSYS;
+        rt_set_errno(EINVAL);
         return -1;
     }
 }
 RTM_EXPORT(settimeofday);
 
+/* inherent in the toolchain */
+RTM_EXPORT(difftime);
+RTM_EXPORT(strftime);
+
 #ifdef RT_USING_POSIX
-static struct timeval _timevalue;
-static int clock_time_system_init()
+
+#ifdef RT_USING_RTC
+static volatile struct timeval _timevalue;
+static int _rt_clock_time_system_init()
 {
-    time_t time;
+    register rt_base_t level;
+    time_t time = 0;
     rt_tick_t tick;
     rt_device_t device;
 
-    time = 0;
     device = rt_device_find("rtc");
     if (device != RT_NULL)
     {
         /* get realtime seconds */
-        rt_device_control(device, RT_DEVICE_CTRL_RTC_GET_TIME, &time);
+        if(rt_device_control(device, RT_DEVICE_CTRL_RTC_GET_TIME, &time) == RT_EOK)
+        {
+            level = rt_hw_interrupt_disable();
+            tick = rt_tick_get(); /* get tick */
+            _timevalue.tv_usec = (tick%RT_TICK_PER_SECOND) * MICROSECOND_PER_TICK;
+            _timevalue.tv_sec = time - tick/RT_TICK_PER_SECOND - 1;
+            rt_hw_interrupt_enable(level);
+            return 0;
+        }
     }
 
-    /* get tick */
-    tick = rt_tick_get();
-
-    _timevalue.tv_usec = (tick%RT_TICK_PER_SECOND) * MICROSECOND_PER_TICK;
-    _timevalue.tv_sec = time - tick/RT_TICK_PER_SECOND - 1;
+    level = rt_hw_interrupt_disable();
+    _timevalue.tv_usec = 0;
+    _timevalue.tv_sec = 0;
+    rt_hw_interrupt_enable(level);
 
-    return 0;
+    return -1;
 }
-INIT_COMPONENT_EXPORT(clock_time_system_init);
+INIT_COMPONENT_EXPORT(_rt_clock_time_system_init);
+#endif /* RT_USING_RTC */
 
 int clock_getres(clockid_t clockid, struct timespec *res)
 {
+#ifndef RT_USING_RTC
+    LOG_W("Cannot find a RTC device to save time!");
+    return -1;
+#else
     int ret = 0;
 
     if (res == RT_NULL)
@@ -429,11 +557,16 @@ int clock_getres(clockid_t clockid, struct timespec *res)
     }
 
     return ret;
+#endif /* RT_USING_RTC */
 }
 RTM_EXPORT(clock_getres);
 
 int clock_gettime(clockid_t clockid, struct timespec *tp)
 {
+#ifndef RT_USING_RTC
+    LOG_W("Cannot find a RTC device to save time!");
+    return -1;
+#else
     int ret = 0;
 
     if (tp == RT_NULL)
@@ -446,11 +579,14 @@ int clock_gettime(clockid_t clockid, struct timespec *tp)
     {
     case CLOCK_REALTIME:
         {
-            /* get tick */
-            int tick = rt_tick_get();
+            int tick;
+            register rt_base_t level;
 
+            level = rt_hw_interrupt_disable();
+            tick = rt_tick_get(); /* get tick */
             tp->tv_sec  = _timevalue.tv_sec + tick / RT_TICK_PER_SECOND;
             tp->tv_nsec = (_timevalue.tv_usec + (tick % RT_TICK_PER_SECOND) * MICROSECOND_PER_TICK) * 1000;
+            rt_hw_interrupt_enable(level);
         }
         break;
 
@@ -474,11 +610,17 @@ int clock_gettime(clockid_t clockid, struct timespec *tp)
     }
 
     return ret;
+#endif /* RT_USING_RTC */
 }
 RTM_EXPORT(clock_gettime);
 
 int clock_settime(clockid_t clockid, const struct timespec *tp)
 {
+#ifndef RT_USING_RTC
+    LOG_W("Cannot find a RTC device to save time!");
+    return -1;
+#else
+    register rt_base_t level;
     int second;
     rt_tick_t tick;
     rt_device_t device;
@@ -486,34 +628,36 @@ int clock_settime(clockid_t clockid, const struct timespec *tp)
     if ((clockid != CLOCK_REALTIME) || (tp == RT_NULL))
     {
         rt_set_errno(EINVAL);
-
         return -1;
     }
 
     /* get second */
     second = tp->tv_sec;
-    /* get tick */
-    tick = rt_tick_get();
 
+    level = rt_hw_interrupt_disable();
+    tick = rt_tick_get(); /* get tick */
     /* update timevalue */
     _timevalue.tv_usec = MICROSECOND_PER_SECOND - (tick % RT_TICK_PER_SECOND) * MICROSECOND_PER_TICK;
     _timevalue.tv_sec = second - tick/RT_TICK_PER_SECOND - 1;
+    rt_hw_interrupt_enable(level);
 
     /* update for RTC device */
     device = rt_device_find("rtc");
     if (device != RT_NULL)
     {
         /* set realtime seconds */
-        rt_device_control(device, RT_DEVICE_CTRL_RTC_SET_TIME, &second);
+        if(rt_device_control(device, RT_DEVICE_CTRL_RTC_SET_TIME, &second) == RT_EOK)
+        {
+            return 0;
+        }
     }
-    else
-        return -1;
 
-    return 0;
+    return -1;
+#endif /* RT_USING_RTC */
 }
 RTM_EXPORT(clock_settime);
 
-int clock_time_to_tick(const struct timespec *time)
+int rt_timespec_to_tick(const struct timespec *time)
 {
     int tick;
     int nsecond, second;
@@ -544,6 +688,32 @@ int clock_time_to_tick(const struct timespec *time)
 
     return tick;
 }
-RTM_EXPORT(clock_time_to_tick);
+RTM_EXPORT(rt_timespec_to_tick);
 
 #endif /* RT_USING_POSIX */
+
+
+/* timezone */
+#ifndef RT_LIBC_DEFAULT_TIMEZONE
+#define RT_LIBC_DEFAULT_TIMEZONE    8
+#endif
+
+static volatile int8_t _current_timezone = RT_LIBC_DEFAULT_TIMEZONE;
+
+void tz_set(int8_t tz)
+{
+    register rt_base_t level;
+    level = rt_hw_interrupt_disable();
+    _current_timezone = tz;
+    rt_hw_interrupt_enable(level);
+}
+
+int8_t tz_get(void)
+{
+    return _current_timezone;
+}
+
+int8_t tz_is_dst(void)
+{
+    return 0;
+}
diff --git a/components/libc/compilers/common/unistd.c b/components/libc/compilers/common/unistd.c
index 0966242e55..9a457c4200 100644
--- a/components/libc/compilers/common/unistd.c
+++ b/components/libc/compilers/common/unistd.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2006-2018, RT-Thread Development Team
+ * Copyright (c) 2006-2021, RT-Thread Development Team
  *
  * SPDX-License-Identifier: Apache-2.0
  *
@@ -15,46 +15,77 @@
 
 #ifdef RT_USING_POSIX_TERMIOS
 #include "termios.h"
-
 int isatty(int fd)
 {
     struct termios ts;
-    return(tcgetattr(fd,&ts) != -1);/*true if no error (is a tty)*/
+    return(tcgetattr(fd, &ts) != -1); /*true if no error (is a tty)*/
+}
+#else
+int isatty(int fd)
+{
+    if (fd >=0 && fd < 3)
+    {
+        return 1;
+    }
+    else
+    {
+        return 0;
+    }
 }
-RTM_EXPORT(isatty);
 #endif
+RTM_EXPORT(isatty);
 
 char *ttyname(int fd)
 {
-    return "/dev/tty0"; /*TODO: need to add more specific*/
+    return "/dev/tty"; /* TODO: need to add more specific */
 }
 RTM_EXPORT(ttyname);
 
 unsigned int sleep(unsigned int seconds)
 {
-    rt_tick_t delta_tick;
-
-    delta_tick = rt_tick_get();
-    rt_thread_delay(seconds * RT_TICK_PER_SECOND);
-    delta_tick = rt_tick_get() - delta_tick;
+    if (rt_thread_self() != RT_NULL)
+    {
+        rt_thread_delay(seconds * RT_TICK_PER_SECOND);
+    }
+    else /* scheduler has not run yet */
+    {
+        while(seconds > 0)
+        {
+            rt_hw_us_delay(1000000u);
+            seconds --;
+        }
+    }
 
-    return seconds - delta_tick/RT_TICK_PER_SECOND;
+    return 0;
 }
 RTM_EXPORT(sleep);
 
 int usleep(useconds_t usec)
 {
-    rt_thread_mdelay(usec / 1000u);
+    if (rt_thread_self() != RT_NULL)
+    {
+        rt_thread_mdelay(usec / 1000u);
+    }
+    else  /* scheduler has not run yet */
+    {
+        rt_hw_us_delay(usec / 1000u);
+    }
     rt_hw_us_delay(usec % 1000u);
+
     return 0;
 }
 RTM_EXPORT(usleep);
 
-pid_t getpid(void)
+pid_t gettid(void)
 {
     /*TODO*/
     return 0;
 }
+
+pid_t getpid(void)
+{
+    return gettid();
+}
 RTM_EXPORT(getpid);
 
 pid_t getppid(void)