serial port support for GNU/Linux

[nikitos1550]

Hi!
For my project I am using ch582f as companion chip for embedded GNU/Linux SoC. Connection interface between chips is uart.
Now I can upgrade ch582f during main SoC boot. Maybe this feature will be also useful for community.

Actually UART protocol is same as USB one:

WCH chips expose similar protocol via UART (UART0 or UART1).
The only difference is prefix and crc:
0x57 0xAB for request
0x55 0xAA for response
CRC is just 8bit all bytes some except prefix.

Proof of work:

$ ./isp55e0 -p /dev/ttyUSB0 -d 
Dump - request
a1 12 00 00 00 4d 43 55 20 49 53 50 20 26 20 57 
43 48 2e 43 4e 
Dump - response
a1 00 02 00 82 16 
Found device CH582
Dump - request
a7 02 00 1f 00 
Dump - response
a7 00 1a 00 1f 00 ff ff ff ff ff ff ff ff 48 0f 
ff 40 00 02 04 00 c1 4d 85 26 3b 38 81 ac 
Bootloader version 2.4.0
Unique chip ID c1-4d-85-26-3b-38-81-ac

$ ./isp55e0 -p /dev/ttyUSB0 -f ./images/blepowermanager-0.0.1.bin 
Found device CH582
Bootloader version 2.4.0
Unique chip ID c1-4d-85-26-3b-38-81-ac
Code flashing successful
Firmware is good

Notes:

• I added serial port support only for GNU/Linux, have no idea how it works under Win. Code became a bit more ugly because of ifdefs.
• I do not know what code formatter do you use, so I tried format code manually in same style.
• For debug mode dumps are printed without additional uart wrapper bytes, I am not sure does it follow your original debug idea or not.

[nikitos1550]

P.S. Also I forget to update README.md :-(

[frank-zago]

Formatting issue here and elsewhere. Lines start with a tab, not 8 spaces.

[frank-zago]

This code follows the linux coding style (or tries to), if that helps.

[frank-zago]

I'd prefer something less verbose:
c = getopt_long(argc, argv, "c:df:hk:l:m:"
#ifndef WIN32
"p:"
#endif
, long_options .....

[frank-zago]

That looks good. Can you also update the help section in the README? And a line to show which device was tested, around line 30.

[nikitos1550]

@frank-zago here you are

[frank-zago]

Sorry. I didn't see that before merging some code. Can you rebase?

[nikitos1550]

@frank-zago rebased.