On Tue, Mar 13, 2012 at 02:16:46PM +0100, Juergen Beisert wrote: > Hi, > > please find attached an DCC based driver for Barebox to be able to get early > boot messages. It acts as a regular serial console and can be used in > conjunction with a JTAG debugger. This is really useful when no serial > console is available (don't ask why...) and the bootloader hangs prior it can > enable a network based console. > > One issue is still present and I need some hints what might be going wrong > here: > > Sending chars via DCC blocks for ever, when I'm using a simple > while loop waiting for the DCC_OUTPUT_BUSY to be cleared. After adding a > timeout loop I receive every other char at the JTAG side. When I write the > char to the DCC even if it timeout, I receive *every* char. Only some chars > are lost when I reduce the timeout value below 750 us. > Any idea? I checked the kernel source, but they doing the same: Waiting for > the DCC_OUTPUT_BUSY to be cleared and timeout after a specific amount of > loops (but without writing the char in this case). > > Comments are welcome. You are probably not aware that we already have such a driver in drivers/serial/arm_dcc.c. Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ barebox mailing list barebox@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/barebox
