Hi Maurine, On 20 January 2015 at 18:02, Ma, Maurice <[email protected]> wrote: > Hi, Simon, > > Just want to make sure that you are talking about the MinnowBoard > (TunnelCreek + TopCliff), not MinnowBoard Max (Baytrail), right? > > For MinnowBoard Max, I have tested and the early serial port does work > before the FSP API call. > > For MinnowBoard, the serial port is from UART0 on TopCliff(EG20T). In order > to enable early console in coreboot, > you need to initialize the TopCliff UART 0 and then call console_init() in > romstage after FSP TempRamInit() and before FspInit(). > > The standard linux UART driver for EG20T is open, you can refer to : > http://lxr.free-electrons.com/source/drivers/tty/serial/pch_uart.c > > You just need to implement the standard RX and TX function for Coreboot. It > should be straight forward. > Please note, since the EG20T UART is on PCI bus and the PCI bus is not > enumerated yet at early boot stage. So you need to assign temporary bus and > PCI MMIO resource to the bridges and the UART controller before accessing the > UART registers.
Yes i it Minnowboard Max. It sounds like you are saying I should get serial output early in romstage, but I don't. Do I need to enable something? Thanks, Simon > > Thanks > Maurice > > -----Original Message----- > From: Hawley, John > Sent: Tuesday, January 20, 2015 3:07 PM > To: MinnowBoard Development and Community Discussion > Cc: Ma, Maurice > Subject: Re: [MinnowBoard] Early serial output > > Maurice might have an answer on this for you. > > Thanks! > > - John 'Warthog9' Hawley > > On 1/17/2015 7:09 PM, Simon Glass wrote: >> Hi, >> >> I see in coreboot there is code to print UART messages in the >> romstage, but nothing appears until romstage_main_continue() is >> called. This is quite late - both the CAR init and FSP init have >> completed by this point. >> >> Is there any way to get earlier serial output? I don't think the board >> has visible POST codes so serial seems to be the only option. >> >> Regards, >> Simon >> _______________________________________________ >> elinux-MinnowBoard mailing list >> [email protected] >> http://lists.elinux.org/mailman/listinfo/elinux-minnowboard >> > _______________________________________________ > elinux-MinnowBoard mailing list > [email protected] > http://lists.elinux.org/mailman/listinfo/elinux-minnowboard _______________________________________________ elinux-MinnowBoard mailing list [email protected] http://lists.elinux.org/mailman/listinfo/elinux-minnowboard
