[PATCH] drivers: char: hvc: add arm JTAG DCC console support

Mike Frysinger vapier at gentoo.org
Fri Apr 8 04:57:51 EST 2011

On Thu, Apr 7, 2011 at 14:39, RONETIX - Asen Dimov wrote:
> On 11/30/2010 09:25 PM, Daniel Walker wrote:
>> This driver adds a basic console that uses the arm JTAG
>> DCC to transfer data back and forth. It has support for
>> ARMv6 and ARMv7.
>> This console is created under the HVC driver, and should be named
>> /dev/hvcX (or /dev/hvc0 for example).
>>  drivers/char/Kconfig   |    9 +++
>>  drivers/char/Makefile  |    1 +
>>  drivers/char/hvc_dcc.c |  133
>> ++++++++++++++++++++++++++++++++++++++++++++++++
> ...
> this DCC driver implements "one channel", but what about implementing
> "multiple channels". For example reserve few(3) bits for channel number,
> and two bits for carried data, then fill the rest bytes with with some data
> and send the word(32 bits) over DCC. On the Linux side writing on /dev/hvcX
> puts the number X as channel number, and on the other side the CPU
> emulator gets the data and redistribute it to TCP/IP socket.
> I have started write some code implementing this. Are there any one
> interested
> in this multiple channels, and are there any one started to work on it?

this sort of multiplexing of the data stream sounds like the job for
userspace ?  or maybe a line discipline ?  inserting structured data
into the kernel driver doesnt sound right to me ...

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