[PATCH] serial: DCC(JTAG) serial and console emulation support

[Tony Lindgren]

* Tony Lindgren <tony at atomide.com> [101008 13:24]:
> * Nicolas Pitre <nico at fluxnic.net> [101007 18:16]:
> > On Thu, 7 Oct 2010, Tony Lindgren wrote:
> > > 
> > > Can you please pass the read and write functions to the driver
> > > in platform_data? We are already booting kernels with both
> > > ARMv6 and 7 compiled in.
> > 
> > No.  This has nothing to do with platform as this can be determined 
> > within the driver itself.  Would be much better to simply determine 
> > which flavor to use at driver init time and assign two function pointers.
> 
> In the long run some platform init code is needed for powering
> up the JTAG interface and take care of pin multiplexing etc.
> 
> Also, isn't DCC (Debug Communications Channel) a JTAG standard? At least
> the following does not say anything about DCC being ARM specific:
> 
> http://en.wikipedia.org/wiki/Joint_Test_Action_Group
> 
> BTW, we already have ETM (Embedded Trace Module) in arch/arm/kernel/etm.c.
> That is set up as amba driver.

Hmm, then again it says this about the scan chains:

  "SCAN_N ... ARM instruction to select the numbered scan chain used
  with EXTEST or INTEST. There are six scan chains"

Which seems like these scan chains are ARM specific.

Regards,

Tony