[U-Boot-Users] s3c2440 -- serial_init

[Harald Welte]

On Fri, Mar 28, 2008 at 04:58:37PM +0530, Tiju wrote:
> Hi all
> 
> I am trying to port u-boot to a s3c2440 samsung processor. 
> 
> I applied the smdk2440 boards patch (almost similar architecture) and
> trying to modify it for our board's requirement. But during the
> serial_init it goes to the _serial_putc and then after certain loops
> it goes to the hang function and hangs there.

this sounds like a flow control issue.  The s3c24xx boards support
hardware flow control handling, i.e. their TX FIFO will not transmit any
more characters unless the RTS/CTS handshake allows it to.

Since the u-boot serial code does an endless loop waiting for the next
character, it will busy-wait there.

Please note that this is true even for UARTs that don't even have
RTS/CTS.  Don't use hw flow control on them.

Another possible cause could be lack of proper GPIO configuration for
the RTS/CTS pins, missing connection on the board, broken serial cable.

Basically anthing that affects RTS/CTS from within the s3c24xx and the
PC on the other side.

-- 
- Harald Welte <laforge at gnumonks.org>           http://laforge.gnumonks.org/
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