I have a problem with serial interface (UART) on embedded Monta Vista,
which included in my DVEVM kit (from Texas Innstruments, the DM355
processor). The core of problem is - after booting, embedded MontaVista
have no serial interfaces in /dev. I use NAND Flash boot procedure with
NFS. But, first of all, console works correct - it means that, at least
one serial (ttyS0) is in system. This serial don't see in /dev, but its initialization can be
founded in kernel ring buffer, so as two others serial ports:
# dmesg | grep tty
ttyS0 at MMIO 0x1c20000 (irq = 40) is a 16550A
ttyS1 at MMIO 0x1c20400 (irq = 41) is a 16550A
ttyS2 at MMIO 0x1e06000 (irq = 14) is a 16550A
First question is - why in console input/output by ttyS0 is accessible, but no devices with this name are in /dev.
Second (and main) problem. I want to use ttyS1 for transmission and receiving data from other external device.
I cann't find it in /dev, like previous and did that
# mknod -m 666 /dev/ttyS1 c 4 65
or
# cd /dev
# ./MAKEDEV ttyS1
After that, device appears
# setrerial -bg /dev/ttyS1
/dev/ttyS1 at 0x0000 (irq = 41) is a 16550A
but with zero port address!
I also did
# setserial /dev/ttyS1 port 0x1c20400
address is from request for 'dmesg | grep tty' command.
At last, it looks like normal device
# setserial -bg /dev/ttyS1
/dev/ttyS1 at 0x1c20400 (irq = 41) is a 16550A
So, I tried to open port - successful. But process of transmit/receive data - don't work at all.
Maybe I maked mistakes, or omit some operations for correct port setup?
And my question is - what can i do for correct config UART and how I can work with it?