[BSP][Nuclei] Add Nuclei RISC-V Processor support

* Nuclei RISC-V Processor support is added both RV32 and RV64
* Nuclei RVSTAR BSP is added, UART driver is added
* MSH works well in RVSTAR board

---------------------------

Squashed commit of the following:

commit b7368bc
Author: Huaqi Fang <[email protected]>
Date:   Fri Apr 17 14:38:54 2020 +0800

    [BSP][Nuclei] Pretty source code

    Signed-off-by: Huaqi Fang <[email protected]>

commit 2c42a99
Author: Huaqi Fang <[email protected]>
Date:   Thu Apr 16 15:51:03 2020 +0800

    [libcpu] Remove ARCH_NUCLEI in libcpu kconfig

    Signed-off-by: Huaqi Fang <[email protected]>

commit 915ad4c
Author: Huaqi Fang <[email protected]>
Date:   Thu Apr 16 15:50:00 2020 +0800

    [BSP][Nuclei] Remove ARCH_NUCLEI in bsp KConfig

    Signed-off-by: Huaqi Fang <[email protected]>

commit fe43869
Author: Huaqi Fang <[email protected]>
Date:   Wed Apr 15 12:43:20 2020 +0800

    [BSP][NUCLEI] Simply application main.c

    Remove previous complicated application of gd32vf103_rvstar

    Signed-off-by: Huaqi Fang <[email protected]>

commit 8fd3172
Author: Huaqi Fang <[email protected]>
Date:   Wed Apr 15 12:38:04 2020 +0800

    [BSP][NUCLEI] Format application and board source code

    Signed-off-by: Huaqi Fang <[email protected]>

commit b432308
Author: Huaqi Fang <[email protected]>
Date:   Wed Apr 15 11:58:28 2020 +0800

    [BSP][Nuclei] Format source code of drivers of gd32vf103

    Signed-off-by: Huaqi Fang <[email protected]>

commit 7366173
Author: Huaqi Fang <[email protected]>
Date:   Wed Apr 15 11:54:02 2020 +0800

    [LIBCPU][NUCLEI] Optimize nuclei cpu portable code

    Signed-off-by: Huaqi Fang <[email protected]>

commit 8c2cd47
Author: Huaqi Fang <[email protected]>
Date:   Tue Apr 14 15:45:42 2020 +0800

    nuclei: Update README.md

    Signed-off-by: Huaqi Fang <[email protected]>

commit fa8a2f2
Author: Huaqi Fang <[email protected]>
Date:   Tue Apr 14 14:06:54 2020 +0800

    nuclei: Add gpio driver not tested

    Signed-off-by: Huaqi Fang <[email protected]>

commit 1be40bc
Author: Huaqi Fang <[email protected]>
Date:   Thu Apr 9 14:55:22 2020 +0800

    Nuclei: Update README.md

    Signed-off-by: Huaqi Fang <[email protected]>

commit 4c8beb2
Author: Huaqi Fang <[email protected]>
Date:   Thu Apr 9 10:20:25 2020 +0800

    Nuclei: Change idle stack size from 256 to 396 bytes

    If changed to 396 bytes, then debug optimization level changed
    from O2 to O0, and the application can run successfully without
    stack overflow issue of tidle0 task
    warning: tidle0 stack is close to end of stack address.

    Signed-off-by: Huaqi Fang <[email protected]>

commit da2bcf5
Author: Huaqi Fang <[email protected]>
Date:   Thu Apr 9 10:11:40 2020 +0800

    nuclei: Remove unused kconfig

    Signed-off-by: Huaqi Fang <[email protected]>

commit 0b932c6
Author: Huaqi Fang <[email protected]>
Date:   Thu Apr 9 09:32:22 2020 +0800

    nuclei: optimize drivers support

    Signed-off-by: Huaqi Fang <[email protected]>

commit 0431f6f
Author: Huaqi Fang <[email protected]>
Date:   Wed Apr 8 19:28:02 2020 +0800

    tools: Update mkdist.py for nuclei bsp

    Signed-off-by: Huaqi Fang <[email protected]>

commit 0e1f502
Author: Huaqi Fang <[email protected]>
Date:   Wed Apr 8 18:46:58 2020 +0800

    nuclei: optimize rvstar support directory

    Signed-off-by: Huaqi Fang <[email protected]>

commit 1131f6e
Author: Huaqi Fang <[email protected]>
Date:   Wed Apr 8 18:37:24 2020 +0800

    nuclei: update kconfig

    Signed-off-by: Huaqi Fang <[email protected]>

commit ad81c1d
Author: Huaqi Fang <[email protected]>
Date:   Wed Apr 8 15:43:00 2020 +0800

    nuclei: Rename board name

    Signed-off-by: Huaqi Fang <[email protected]>

commit d780138
Author: Huaqi Fang <[email protected]>
Date:   Tue Apr 7 09:36:19 2020 +0800

    libcpu: Add Nuclei arch option in KConfig

    Signed-off-by: Huaqi Fang <[email protected]>

commit 60320d3
Author: Huaqi Fang <[email protected]>
Date:   Fri Apr 3 16:51:01 2020 +0800

    nuclei: Update nuclei sdk of rt-thread support

    Signed-off-by: Huaqi Fang <[email protected]>

commit a042b80
Author: Huaqi Fang <[email protected]>
Date:   Fri Apr 3 11:34:09 2020 +0800

    nuclei: modify application for not print anything

    Signed-off-by: Huaqi Fang <[email protected]>

commit 2a9603a
Author: Huaqi Fang <[email protected]>
Date:   Fri Apr 3 11:31:01 2020 +0800

    nuclei: Add .gitignore for nuclei bsp

    Signed-off-by: Huaqi Fang <[email protected]>

commit 34aaf6a
Author: Huaqi Fang <[email protected]>
Date:   Fri Apr 3 11:28:06 2020 +0800

    nuclei_sdk: update link script of rvstar to contain rt-thread needed sections

            /* section information for finsh shell */
            . = ALIGN(4);
            __fsymtab_start = .;
            KEEP(*(FSymTab))
            __fsymtab_end = .;

            . = ALIGN(4);
            __vsymtab_start = .;
            KEEP(*(VSymTab))
            __vsymtab_end = .;

            /* section information for initial. */
            . = ALIGN(4);
            __rt_init_start = .;
            KEEP(*(SORT(.rti_fn*)))
            __rt_init_end = .;

    The above code placed in rodata section

    Signed-off-by: Huaqi Fang <[email protected]>

commit 3451466
Author: Huaqi Fang <[email protected]>
Date:   Fri Apr 3 10:04:42 2020 +0800

    bsp: Add initial commit of nuclei rvstar board bsp

    Signed-off-by: Huaqi Fang <[email protected]>

Signed-off-by: Huaqi Fang <[email protected]>

Author: fanghuaqi

bsp/nuclei/.gitignore

@@ -0,0 +1,26 @@
+*.i
+*.o
+*.d
+*.elf
+*.diss
+*.map
+*.bin
+*.log
+.vscode
+
+*.dump
+*.verilog
+
+*.swp
+*.swo
+
+prebuilt_tools/
+setup_config.sh
+setup_config.bat
+
+tags
+TAGS
+TAG
+CTAGS
+Makefile.local
+Makefile.global