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Date:   Wed, 30 Mar 2022 09:54:22 +0200
From:   Marc Kleine-Budde <mkl@pengutronix.de>
To:     Ondrej Ille <ondrej.ille@gmail.com>
Cc:     Pavel Pisa <pisa@cmp.felk.cvut.cz>, linux-can@vger.kernel.org,
        devicetree@vger.kernel.org,
        Oliver Hartkopp <socketcan@hartkopp.net>,
        Wolfgang Grandegger <wg@grandegger.com>,
        David Miller <davem@davemloft.net>,
        Rob Herring <robh+dt@kernel.org>, mark.rutland@arm.com,
        Carsten Emde <c.emde@osadl.org>, armbru@redhat.com,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        Marin Jerabek <martin.jerabek01@gmail.com>,
        Jiri Novak <jnovak@fel.cvut.cz>,
        Jaroslav Beran <jara.beran@gmail.com>,
        Petr Porazil <porazil@pikron.com>, Pavel Machek <pavel@ucw.cz>,
        Drew Fustini <pdp7pdp7@gmail.com>
Subject: Re: [PATCH v8 0/7] CTU CAN FD open-source IP core SocketCAN driver,
 PCI, platform integration and documentation
Message-ID: <20220330075422.4kxnayrdcxz7o5lo@pengutronix.de>
References: <cover.1647904780.git.pisa@cmp.felk.cvut.cz>
 <202203220918.33033.pisa@cmp.felk.cvut.cz>
 <20220322092212.f5eaxm5k45j5khra@pengutronix.de>
 <202203221419.23089.pisa@cmp.felk.cvut.cz>
 <CAA7ZjpZbppBy_C+NyN4LWQF2-a-ktfjYeNELTzwsz4B-fBiTpw@mail.gmail.com>
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On 30.03.2022 09:46:08, Ondrej Ille wrote:
> sorry for the late reply, my work duties are keeping me very busy.

Known problem :)

> Let me just quickly comment on topics discussed in the emails above.
>=20
> *1. Separation of PROP and TSEG1*
>=20
> IMHO there is no real benefit. The reason why CTU CAN FD has this
> split is legacy. First implementation back in 2015 had this split
> since I wanted to follow the standard. In HW, the first thing done in
> bit timing logic (prescaler module), these two numbers are added, and
> all further resynchronization/hard-synchronization is done with TSEG1
> value...

Thanks for the insight. It's not easy to get in touch with the
developers of the proprietary IP cores :)

Never the less, there's another IP core which has different sizes for
the prop and tseg1 register. So an update of the bit timing constant
would help both.

> *2. Number of TXT Buffers and RX Buffer size:*
>=20
> Pavel already replied with TXTB_INFO. The same role has the RX_MEM_INFO
> register, when it comes to RX side.

Thanks for the clarification.

regards,
Marc

--=20
Pengutronix e.K.                 | Marc Kleine-Budde           |
Embedded Linux                   | https://www.pengutronix.de  |
Vertretung West/Dortmund         | Phone: +49-231-2826-924     |
Amtsgericht Hildesheim, HRA 2686 | Fax:   +49-5121-206917-5555 |

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