serial port communication is broken with SG2002 cpu native uart

[nikitos1550]

Hi!

Before I made patch, that add serial port communications and it was worked well. But I tested it with usb serial adapter. Recently I used sg2002 based system with native hw uart and faced that serial communication is broken with ch573f. read() request returns less data then expected.

Now I made local patch

diff --git a/isp55e0.c b/isp55e0.c
index 3811166..70de7e0 100644
--- a/isp55e0.c
+++ b/isp55e0.c
@@ -137,7 +137,7 @@ static void open_serial_device(struct device *dev, char *port)
        /* Disable any special handling of received bytes */
        options.c_iflag &= ~(IGNBRK | BRKINT | PARMRK | ISTRIP | INLCR | IGNCR | ICRNL);

-       options.c_cc [VMIN]  = 0;
+       options.c_cc [VMIN]  = 64;
        options.c_cc [VTIME] = SERIAL_TIMEOUT;

        ret = tcsetattr(dev->fd, TCSANOW, &options) ;

I am posting this here now as a memo, after I will complete all tests, I think I will have a time to put full PR.

[nikitos1550]

MYSERIAL:~# isp55e0 -p /dev/ttyS1 -f /lib/firmware/blepowermanager-ch57xf-test-uart1-echo.bin 
Found device CH573
Bootloader version 2.9.0
Unique chip ID dd-cf-57-7b-54-50-88-9b
Code flashing successful
Firmware is good

Seems patch is ok.