From: Marc Kleine-Budde <mkl@pengutronix.de>
To: Ramesh Shanmugasundaram <ramesh.shanmugasundaram@bp.renesas.com>,
Oliver Hartkopp <socketcan@hartkopp.net>,
"wg@grandegger.com" <wg@grandegger.com>,
"robh+dt@kernel.org" <robh+dt@kernel.org>,
"pawel.moll@arm.com" <pawel.moll@arm.com>,
"mark.rutland@arm.com" <mark.rutland@arm.com>,
"ijc+devicetree@hellion.org.uk" <ijc+devicetree@hellion.org.uk>,
"galak@codeaurora.org" <galak@codeaurora.org>,
"corbet@lwn.net" <corbet@lwn.net>
Cc: "linux-renesas-soc@vger.kernel.org"
<linux-renesas-soc@vger.kernel.org>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
"linux-can@vger.kernel.org" <linux-can@vger.kernel.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>,
"geert+renesas@glider.be" <geert+renesas@glider.be>,
Chris Paterson <Chris.Paterson2@renesas.com>
Subject: Re: [PATCH v2] can: rcar_canfd: Add Renesas R-Car CAN FD driver
Date: Mon, 7 Mar 2016 09:08:21 +0100 [thread overview]
Message-ID: <56DD36F5.2000308@pengutronix.de> (raw)
In-Reply-To: <SG2PR06MB10386D712BC8C345DF726523C3B10@SG2PR06MB1038.apcprd06.prod.outlook.com>
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On 03/07/2016 09:02 AM, Ramesh Shanmugasundaram wrote:
> Hi Oliver,
>
> Thanks for the review comments.
>
>> On 03/03/2016 04:38 PM, Ramesh Shanmugasundaram wrote:
>>
>>> Changes since v1:
>>> * Removed testmodes & debugfs code (suggested by Oliver H)
>>> * Fixed tx path race issue by introducing lock (suggested by Marc K)
>>> * Removed __maybe_unused attribute of rcar_canfd_of_table
>>>
>>
>>
>>> obj-$(CONFIG_CAN_M_CAN) += m_can/
>>> obj-$(CONFIG_CAN_RCAR) += rcar_can.o
>>> +obj-$(CONFIG_CANFD_RCAR) += rcar_canfd.o
>>
>> Just for the sake of an ordered directory structure:
>>
>> Would it make sense to create a rcar directory where rcar_can.c and
>> rcar_canfd.c are placed?
>>
> Yes. I'll place them in rcar dir.
>
>> Additionally (besides of one accident with the obsolete PCH_CAN) all CAN
>> drivers start with CONFIG_CAN_...
>>
>> Following that scheme the config option should be named
>>
>> CONFIG_CAN_RCAR_CANFD
>>
>> as we had in CONFIG_CAN_IFI_CANFD.
>
> Agreed.
>
>>
>>> obj-$(CONFIG_CAN_SJA1000) += sja1000/
>>> obj-$(CONFIG_CAN_SUN4I) += sun4i_can.o
>>> obj-$(CONFIG_CAN_TI_HECC) += ti_hecc.o
>>> diff --git a/drivers/net/can/rcar_canfd.c
>>> b/drivers/net/can/rcar_canfd.c
>>
>> (..)
>>
>>> +/* Channel priv data */
>>> +struct rcar_canfd_channel {
>>> + struct can_priv can; /* Must be the first member */
>>> + struct net_device *ndev;
>>> + struct rcar_canfd_global *gpriv; /* Controller reference */
>>> + void __iomem *base; /* Register base address */
>>> +#ifdef CONFIG_DEBUG_FS
>>> + struct dentry *dev_root;
>>> +#endif /* CONFIG_DEBUG_FS */
>>
>> Some missed stuff from debugfs removal?
>
> :-(. Sorry. Will clean up.
>
>>
>>> + struct napi_struct napi;
>>> + u8 tx_len[RCANFD_FIFO_DEPTH]; /* For net stats */
>>> + u32 tx_head; /* Incremented on xmit */
>>> + u32 tx_tail; /* Incremented on xmit done */
>>> + u32 channel; /* Channel number */
>>> + spinlock_t tx_lock; /* To protect tx path */
>>> +};
>>
>> (..)
>>
>>> +static int rcar_canfd_start(struct net_device *ndev) {
>>> + struct rcar_canfd_channel *priv = netdev_priv(ndev);
>>> + int err = -EOPNOTSUPP;
>>> + u32 sts, ch = priv->channel;
>>> + u32 ridx = ch + RCANFD_RFFIFO_IDX;
>>> +
>>> + /* Ensure channel starts in FD mode */
>>> + if (!(priv->can.ctrlmode & CAN_CTRLMODE_FD)) {
>>> + netdev_err(ndev, "enable can fd mode for channel %d\n", ch);
>>> + goto fail_mode;
>>> + }
>>
>> What's the reason behind this check?
>>
>> A CAN FD capable CAN controller can be either configured to run as CAN 2.0
>> (Classic CAN) or as CAN FD controller.
>>
>> So why are to throwing an error here and produce an initialization
>> failure?
>
> When this controller is configured in FD mode and used only with CAN 2.0 nodes, it still expects a DTSEG (data bitrate) configuration same as NTSEG (nominal bitrate). This check, specifically in ndo_open, ensures both are configured and will work fine with CAN 2.0 nodes (e.g.)
>
> "ip link set can0 up type can bitrate 1000000 dbitrate 1000000 fd on"
>
> If I don't have this check, a configuration like this
>
> "ip link set can0 up type can bitrate 1000000"
>
> will bring up the controller without DTSEG configured.
That should bring up the controller in CAN 2.0 mode.
Marc
--
Pengutronix e.K. | Marc Kleine-Budde |
Industrial Linux Solutions | Phone: +49-231-2826-924 |
Vertretung West/Dortmund | Fax: +49-5121-206917-5555 |
Amtsgericht Hildesheim, HRA 2686 | http://www.pengutronix.de |
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next prev parent reply other threads:[~2016-03-07 8:08 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-01 9:34 [PATCH] can: rcar_canfd: Add Renesas R-Car CAN FD driver Ramesh Shanmugasundaram
[not found] ` <1456824849-7987-1-git-send-email-ramesh.shanmugasundaram-kTT6dE0pTRh9uiUsa/gSgQ@public.gmane.org>
2016-03-01 20:41 ` Marc Kleine-Budde
2016-03-02 8:41 ` Ramesh Shanmugasundaram
2016-03-02 9:20 ` Marc Kleine-Budde
2016-03-02 10:08 ` Ramesh Shanmugasundaram
2016-03-02 10:21 ` Marc Kleine-Budde
2016-03-03 13:48 ` Ramesh Shanmugasundaram
2016-03-01 21:07 ` Oliver Hartkopp
2016-03-02 8:45 ` Ramesh Shanmugasundaram
2016-03-03 15:38 ` [PATCH v2] " Ramesh Shanmugasundaram
2016-03-05 4:30 ` Rob Herring
2016-03-07 9:33 ` Ramesh Shanmugasundaram
2016-03-06 11:32 ` Oliver Hartkopp
2016-03-07 8:02 ` Ramesh Shanmugasundaram
2016-03-07 8:08 ` Marc Kleine-Budde [this message]
2016-03-07 8:32 ` Ramesh Shanmugasundaram
2016-03-08 7:46 ` Oliver Hartkopp
2016-03-08 8:57 ` Ramesh Shanmugasundaram
2016-03-08 12:25 ` Oliver Hartkopp
2016-03-08 12:48 ` Ramesh Shanmugasundaram
2016-03-08 17:16 ` Oliver Hartkopp
2016-03-11 7:14 ` Ramesh Shanmugasundaram
2016-03-12 18:49 ` Oliver Hartkopp
2016-03-15 9:48 ` [PATCH v3] " Ramesh Shanmugasundaram
2016-03-15 12:51 ` Marc Kleine-Budde
2016-03-15 14:26 ` Ramesh Shanmugasundaram
2016-03-18 21:07 ` Rob Herring
2016-03-21 16:45 ` [PATCH v4 0/2] Add CAN FD driver support to r8a7795 SoC Ramesh Shanmugasundaram
2016-03-21 16:45 ` [PATCH 1/2] can: rcar_canfd: Add Renesas R-Car CAN FD driver Ramesh Shanmugasundaram
2016-03-21 16:45 ` [PATCH 2/2] can: rcar_can: Move Renesas CAN driver to rcar dir Ramesh Shanmugasundaram
2016-03-31 20:51 ` [PATCH v2] can: rcar_canfd: Add Renesas R-Car CAN FD driver Marc Kleine-Budde
2016-04-01 12:48 ` Ramesh Shanmugasundaram
2016-04-13 6:25 ` Ramesh Shanmugasundaram
2016-04-28 6:27 ` Oliver Hartkopp
2016-04-28 12:31 ` Ramesh Shanmugasundaram
2016-04-28 12:23 ` [PATCH v5 0/2] Add CAN FD driver support to r8a7795 SoC Ramesh Shanmugasundaram
2016-04-28 12:23 ` [PATCH v5 1/2] can: rcar_canfd: Add Renesas R-Car CAN FD driver Ramesh Shanmugasundaram
2016-05-03 16:47 ` Rob Herring
2016-05-04 6:23 ` Ramesh Shanmugasundaram
2016-04-28 12:23 ` [PATCH v5 2/2] can: rcar_can: Move Renesas CAN driver to rcar dir Ramesh Shanmugasundaram
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