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From: Jakub Kicinski <kuba@kernel.org>
To: "Köry Maincent" <kory.maincent@bootlin.com>
Cc: "Russell King (Oracle)" <linux@armlinux.org.uk>,
	Richard Cochran <richardcochran@gmail.com>,
	andrew@lunn.ch, davem@davemloft.net, f.fainelli@gmail.com,
	hkallweit1@gmail.com, netdev@vger.kernel.org,
	Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
	Maxime Chevallier <maxime.chevallier@bootlin.com>
Subject: Re: [PATCH RFC net-next] net: phy: add Marvell PHY PTP support [multicast/DSA issues]
Date: Fri, 3 Mar 2023 15:28:55 -0800	[thread overview]
Message-ID: <20230303152855.23588b39@kernel.org> (raw)
In-Reply-To: <20230303141247.4acd6863@kmaincent-XPS-13-7390>

On Fri, 3 Mar 2023 14:12:47 +0100 Köry Maincent wrote:
> > Do you happen to have a datasheet for MACB? The time stamping
> > capability is suspiciously saved in a variable called hw_dma_cap
> > which may indicate it's a DMA time stamp not a true PTP stamp.
> > 
> > Quite a few NICs/MACs support DMA time stamps because it's far 
> > easier to take the stamp where the descriptor writing logic is
> > (DMA block) than take it at the end of the MAC and haul it all 
> > the way thru the pipeline back to the DMA block.  
> 
> I don't have the datasheet but indeed you seem to have right. From the support
> commit message: 
> > Time stamps are obtained from the dma buffer descriptors  

That's just saying that the time stamp is communicated via 
a descriptor rather than a register, so not a strong proof 
of where it's taken.

> I suppose it is less precise as using true PTP stamp as it is an hardware block
> further. Is that right?

  reply	other threads:[~2023-03-03 23:29 UTC|newest]

Thread overview: 74+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-14 16:26 [PATCH RFC net-next] net: phy: add Marvell PHY PTP support Russell King
2020-07-15 18:38 ` Andrew Lunn
2020-07-15 18:56   ` Russell King - ARM Linux admin
2020-07-16 11:33     ` Russell King - ARM Linux admin
2020-07-16 20:53       ` Richard Cochran
2020-07-16 20:48 ` Richard Cochran
2020-07-17  7:54   ` Kurt Kanzenbach
2020-07-18  2:24     ` Richard Cochran
2020-07-20 14:21       ` Richard Cochran
2020-07-20 14:37         ` Kurt Kanzenbach
2020-07-26 23:48 ` Russell King - ARM Linux admin
2020-07-29 10:58 ` Russell King - ARM Linux admin
2020-07-29 13:19   ` Richard Cochran
2020-07-29 13:28     ` Russell King - ARM Linux admin
2020-07-29 22:07       ` Russell King - ARM Linux admin
2020-07-29 22:53         ` Vladimir Oltean
2020-07-30 15:53         ` Richard Cochran
2020-07-30 18:38           ` Russell King - ARM Linux admin
2020-07-30 19:32             ` Richard Cochran
2020-07-30 19:44               ` Russell King - ARM Linux admin
2020-07-30 11:06     ` [PATCH RFC net-next] net: phy: add Marvell PHY PTP support [multicast/DSA issues] Russell King - ARM Linux admin
2020-07-30 11:54       ` Russell King - ARM Linux admin
2020-07-30 12:47         ` Russell King - ARM Linux admin
2023-02-27 14:40           ` Köry Maincent
2023-02-27 15:20             ` Russell King (Oracle)
2023-02-27 17:30               ` Köry Maincent
2023-02-27 17:42                 ` Russell King (Oracle)
2023-02-27 19:45               ` Richard Cochran
2023-02-27 20:09                 ` Russell King (Oracle)
2023-02-27 20:19                   ` Richard Cochran
2023-02-28 12:07                     ` Russell King (Oracle)
2023-02-28 13:16                       ` Köry Maincent
2023-02-28 13:36                         ` Russell King (Oracle)
2023-02-28 14:50                           ` Köry Maincent
2023-02-28 15:16                         ` Richard Cochran
2023-02-28 15:33                           ` Andrew Lunn
2023-02-28 21:13                             ` Richard Cochran
2023-02-28 16:27                           ` Russell King (Oracle)
2023-02-28 16:44                             ` Michael Walle
2023-02-28 16:58                               ` Russell King (Oracle)
2023-02-28 20:13                                 ` Michael Walle
2023-02-28 21:11                                   ` Richard Cochran
2023-02-28 21:24                             ` Richard Cochran
2023-02-28 22:26                             ` Jakub Kicinski
2023-02-28 22:40                               ` Russell King (Oracle)
2023-02-28 22:59                                 ` Jakub Kicinski
2023-03-01 16:04                                   ` Köry Maincent
2023-03-02  4:36                                     ` Richard Cochran
2023-03-02 11:49                                       ` Russell King (Oracle)
2023-03-02 16:49                                         ` Jakub Kicinski
2023-03-02 17:06                                           ` Köry Maincent
2023-03-02 17:23                                             ` Jakub Kicinski
2023-03-03 13:12                                               ` Köry Maincent
2023-03-03 23:28                                                 ` Jakub Kicinski [this message]
2023-03-02 17:26                                           ` Russell King (Oracle)
2023-03-03 10:20                                             ` Michael Walle
2023-03-03 13:20                                               ` Andrew Lunn
2023-03-03 13:34                                                 ` Köry Maincent
2023-03-03 13:59                                                   ` Andrew Lunn
2023-03-03 14:03                                                 ` Russell King (Oracle)
2023-03-03 16:34                                                   ` Andrew Lunn
2023-03-03 17:32                                                     ` Richard Cochran
2023-03-03 17:35                                                       ` Richard Cochran
2023-03-03 23:40                                                   ` Jakub Kicinski
2023-03-02 21:28                                           ` Richard Cochran
2023-03-02 21:19                                         ` Richard Cochran
2023-04-27 15:13               ` Köry Maincent
2023-04-27 16:50                 ` Andrew Lunn
2023-04-28  8:51                   ` Köry Maincent
2020-07-30 15:50         ` Richard Cochran
2020-07-31 14:41         ` Andrew Lunn
2023-03-02 10:37   ` [PATCH RFC net-next] net: phy: add Marvell PHY PTP support Köry Maincent
2023-03-02 17:38     ` Russell King (Oracle)
2023-03-02 21:35     ` Richard Cochran

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