[RFC] ARM/serial: add a DCC based console driver

[Juergen Beisert]

Myself wrote:
> [...]
> 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).
> [...]

Forget about that. The dcc_serial_putc() is broken in this patch. My ARMv5 
*always* signals a DCC_OUTPUT_BUSY. If I ignore this bit and just wait about 
750 µs between the chars it works as expected. Still have to find out, why it 
always signals a DCC_OUTPUT_BUSY...

jbe

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