[U-Boot-Users] How console redirection is done

Joey Oravec
2007-07-13T12:14:40Z

"Ori Idan" <ori@helicontech.co.il> wrote in message
news:65487840707122317ve675e94x222e48968a8a730b at mail.gmail.com...
>I am sorry, I can not understand the question.
> U-boot always outputs to serial port.
> If you would like to change to another serial port look at the
> configuration file corresponding to your board under include/configs.

That's not exactly true. After the initial console (bootup) you can use more
than serial.

There are a few functions like drv_lcd_init in lcd.c that create a device_t
structure -- in my version they're all called within devices_init in
common/devices.c during boot. This defines a putc, puts, getc, and tstc to
handle I/O character by character. Once you call device_register() it will
available to the system. Using the environment variables stdin, stdout, and
stderr you can choose which device is active, and console.c calls the
appropriate function pointer. Set the variable and you can be printing on
the LCD instead.

Of course all this can be changed with a million CONFIG_ parameters, and it
is a little strange if you have several consoles available and no default.

-joey