Re: [PATCH v3 14/14] can: peak_usb: advertise timestamping capabilities and add ioctl support - Marc Kleine-Budde

From: Marc Kleine-Budde <mkl@pengutronix.de>
To: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Cc: linux-can@vger.kernel.org,
	Stephane Grosjean <s.grosjean@peak-system.com>,
	Jimmy Assarsson <extja@kvaser.com>,
	Oliver Hartkopp <socketcan@hartkopp.net>,
	Dario Binacchi <dario.binacchi@amarulasolutions.com>,
	Max Staudt <max@enpas.org>
Subject: Re: [PATCH v3 14/14] can: peak_usb: advertise timestamping capabilities and add ioctl support
Date: Wed, 27 Jul 2022 10:06:34 +0200	[thread overview]
Message-ID: <20220727080634.l6uttnbrmwbabh3o@pengutronix.de> (raw)
In-Reply-To: <20220726102454.95096-15-mailhol.vincent@wanadoo.fr>

[-- Attachment #1: Type: text/plain, Size: 2294 bytes --]

On 26.07.2022 19:24:54, Vincent Mailhol wrote:
> Currently, userland has no method to query which timestamping features
> are supported by the peak_usb driver (aside maybe of getting RX
> messages and obseverse whever or not hardware timestamps stay at
> zero).
> 
> The canonical way for a network driver to advertise what kind of
> timestamping it supports is to implement
> ethtool_ops::get_ts_info(). Here, we use the CAN specific
> can_ethtool_op_get_ts_info_hwts() function to achieve this.
> 
> In addition, the driver currently does not support the hardware
> timestamps ioctls. According to [1], SIOCSHWTSTAMP is "must" and
> SIOCGHWTSTAMP is "should". This patch fills up that gap by
> implementing net_device_ops::ndo_eth_ioctl() using the CAN specific
> function can_eth_ioctl_hwts().
> 
> [1] kernel doc Timestamping, section 3.1: "Hardware Timestamping
> Implementation: Device Drivers"
> Link: https://docs.kernel.org/networking/timestamping.html#hardware-timestamping-implementation-device-drivers
> 
> CC: Stephane Grosjean <s.grosjean@peak-system.com>
> Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
> ---
> 
> Hi Stéphane, as far as I understand, the pcan_usb and the pacn_usb_pro
                                                            ^^^^
                                                            pcan

> support hardware timestamps but the pcan_usb_fd doesn't. If not the
> case, let me know.
> 
> This is not tested. If you find any issue or if you want to modify,
> feel free to pick up that patch and resend it.

I have a:

| Bus 002 Device 009: ID 0c72:0012 PEAK System PCAN-USB FD

It supports hardware RX timestamps (Debian kernel 5.18.0-2-amd64) only:

|  (1970-01-01 01:00:00.000000)  peakfd0  TX - -  002   [1]  01
|  (1970-01-01 02:17:09.473817)  peakfd0  RX - -  002   [1]  3C
|  (1970-01-01 01:00:00.000000)  peakfd0  TX - -  002   [1]  02
|  (1970-01-01 02:17:09.673980)  peakfd0  RX - -  002   [1]  3D

regards,
Marc

-- 
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 |

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 488 bytes --]