Beaglebone Serial Ports

Ian Lepore ian at FreeBSD.org
Sat Feb 2 15:13:34 UTC 2013


On Sat, 2013-02-02 at 10:22 +0000, Iain Young wrote:
> Hi Folks,
> 
> Just a quick question with regards to some clarification serial ports
> on the Beaglbone and FreeBSD. Am I correct in deducing that FreeBSD
> lacks support for UARTS1 thru 5 at the moment ?
> 
> I can see what I believe to be UART0 (which is attached to the USB) as
> /dev/cuau0, but not the others. A few finds and greps through the
> kernel source didn't show up anything obvious either.
> 
> Is any one working on them ? Or is there a kernel module or option
> that I need to enable for them to build ?
> 

According to the datasheet all the onboard uarts should be supported by
our standard uart driver (but only uart1 has all the modem-control lines
wired).  Two things need to be done to enable them: add entries to
the .dts file (easy), and configure the multipurpose pins for them at
runtime.  I have no idea how we handle the latter in the FDT world.  In
the pre-FDT world it was pretty much ad-hoc and board-support routines
that ran at startup configured pins for that board.

-- Ian




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