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From: Andrzej Kaczmarek <andrzej.kaczmarek@codecoup.pl>
Date: Thu, 22 Feb 2018 13:20:08 +0100
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Subject: Re: [PATCH BlueZ 0/3] Receiving monitor data stream over RTT
To: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Cc: "linux-bluetooth@vger.kernel.org" <linux-bluetooth@vger.kernel.org>
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Hi Luiz,

On Thu, Feb 22, 2018 at 12:14 PM, Luiz Augusto von Dentz
<luiz.dentz@gmail.com> wrote:
> Hi Andrzej,
>
> On Thu, Feb 22, 2018 at 11:20 AM, Andrzej Kaczmarek
> <andrzej.kaczmarek@codecoup.pl> wrote:
>> Hi,
>>
>> Here's patch series which adds support for receiving monitor data stream over
>> Segger RTT channel. This allows to stream data from embedded device without
>> need to spare a UART for monitor data and is also much faster. It is now
>> supported by Apache Mynewt (NimBLE stack), but I believe it can be also added
>> to other RTOS-es like Zephyr Project.
>>
>> RTT is handled natively by talking to J-Link via libjlinkarm.so. Since there
>> is no public documentation for this library, interface was done mostly by
>> trial and error so it may be lacking something - I tried it with few Cortex-M
>> devices and it works smoothly.
>>
>> Both J-Link and RTT needs few configuration parameters to work so I combined
>> them into two command line options:
>>   -J --jlink <device>,<interface>,<speed>,<serialno>
>>   -R --rtt <address>,<area>,<buffer>
>>
>> <device> - one of devices supported by J-Link (no default)
>> <interface> - only 'swd' supported for now (default: swd)
>> <speed> - interface speed (default: 1000)
>> <serialno> - emu serial number or 0 if not used (detault: 0)
>> <address> - RTT control block address (default: 0)
>> <area> - RTT control block search area length (default: 0)
>> <buffer> - RTT buffer name with monitor data stream (default: monitor)
>
> Given that the device has no default I suppose it is not able to
> auto-detect it, wouldn't it be possible to add support for that? At
> least the tools for flashing, etc, do seems to be able to detect when
> using a j-tag.

I'm not sure if it is any different over JTAG, but I don't think
J-Link can autodetect device over SWD (which I only implemented now) -
you need to specify at least core in order to be able to connect to
target.

>>
>> Andrzej Kaczmarek (3):
>>   monitor: Extract TTY data processing to separate function
>>   monitor: Add interface for J-Link library
>>   monitor: Add support for reading over J-Link RTT
>>
>>  Makefile.tools    |   3 +-
>>  monitor/control.c |  87 +++++++++++++----
>>  monitor/control.h |   1 +
>>  monitor/jlink.c   | 282 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
>>  monitor/jlink.h   |  27 ++++++
>>  monitor/main.c    |  30 +++++-
>>  6 files changed, 409 insertions(+), 21 deletions(-)
>>  create mode 100644 monitor/jlink.c
>>  create mode 100644 monitor/jlink.h
>>
>> --
>> 2.16.2
>>
>> --
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>
>
>
> --
> Luiz Augusto von Dentz

Best regards,
Andrzej