System will crash when the romfs is erased. Add checks before using them
to avoid it.

sync

Move PNG_NO_WRITE_SUPPORTED outside of RT_USING_NEWLIB. #197

Frequent 'C' on the handshake will confuse some sender(lrzsz for
example).

Make fast path fast and slow path slow.

2. Fix data transfer size calculate error issue;

add some comments of lwip porting

The ptr is set in the following code. So remove the first one.

The digit in octal numbers should with in 0~7. Check on it in
token_proc_number. This issue is found by Clang.

Clang complains about "Null pointer argument in call to string
comparison function". So assert on it.

log_session_lvl is suitable for performance critical places where in
most cases, the log is turned off by level. If the session is const and
the level is greater than session->lvl, the whole function will be
optimized out.

Compiler may do more optimization when the parameter is const.

[USB]fix rt_usbd_set_config() BUG which set the USB device to configurat...

When MSH enabled, the prompt will change at the two shells. So we should
use dynamic prompt when FINSH_USING_MSH defined.

[msh] don't complain on empty command

Just branch out and no complain on command length == 0;

When DFS_USING_WORKDIR is enabled, msh will try to chdir if the command
is not found. For example, if there is folder named "SD", and there is
no `SD` command and `SD.mo` module, typing "SD" in msh will cd to the
folder.

In more detail, the execution order right now is:

1. built-in command
2. module
3. cd to path

If you have a folder named "ps", you have to run `cd ps` to change the
working dir.

Msh can execute module directly. So try to auto-complete the path when
user press TAB. There is a chance that the path is a module.

2.adjust some viable and micro name
3.some other small fix

This reverts commit 5aeedc4f3a, reversing
changes made to 3d80e414ff.

This merge breaks every uart driver in all BSPs. @bright-pan , is there
any way to get this done without breaking existing code?

Add hardware flow support.
Use new struct serial_ringbuffer.

Pass USB CV test verification;
Code cleanup;

This issue causes fstat & lseek not correct.

update CMSIS version to 3.20

fix msh_exec(char* cmd, rt_size_t length) bug

I have to mention that this bug is introduced by myself, in the last
commit <fd07f30f511335f506ae6557e300093d4dde421e> to dfs_nfs.c

fix dfs_unmount bug

more infomation:
http://www.rt-thread.org/phpBB3/topic2965.html

fix #211

empty is confused in dfs_filesystem_lookup.

clean code with pointer rather than index

decrease indentation to make cleaner code
fix mkfs bug when there is no mkfs implementation

1. rt_console_get_device should be call to set shell device only when it is null, or it will make finsh_set_device useless.
2. RT_USING_CONSOLE can be disabled in bsp/rtconfig.h

On Windows platform, please set `autocrlf = true` and on Linux, please
set `autocrlf = input`.

Signed-off-by: armink <armink.ztl@gmail.com>

Signed-off-by: armink <armink.ztl@gmail.com>

This reverts commit 07bd09fc0f.
The validation of the context is done with in `rt_set_errno`. So it's
safe to call it here.

The errno is associated with threads. It will crash the thread if we set
it in interrupt context.

Return early if the size is 0 as there is nothing to do.

Finsh ex

We split the history handling form the key handling. So we could handle
the direction key even if the history is disabled. As a "side effect", I
also remove the unnecessary "use_history" bit.

UART DMA tx_complete() with buffer information

_TIME_T_DEFINED was pre-defined in order to build jffs2 with VC.
While it may cause many side effects.

DFS: add dfs_file_flush prototype in dfs_file.h

The first parameter of memmove is the dst, not src. Besides, fix the
wrong move size.

components/utilities: add ymodem

Real-YModem implemented a flexible YModem support. It use callback-based
structure to let the user application to deal with the data. It contains
3 examples:

    1. echo.c: write the data recieved on YModem to an other device
    2. null.c: discard the YModem data
    3. tofile.c: write the data to the file system

Currently, it does not support batch file transmission.

found by haitao5198
clear mount parition device talbe when jffs2 mount falied

found by haitao52198
URL:http://www.rt-thread.org/phpBB3/viewtopic.php?f=3&t=3112&p=17153#p17153

*buffer) with buffer pointer

logtrace only use odd number of log levels. So the use could set some
custom level amount them.