From: Marc Kleine-Budde <mkl@pengutronix.de>
To: Markus Schneider-Pargmann <msp@baylibre.com>
Cc: Chandrasekar Ramakrishnan <rcsekar@samsung.com>,
Wolfgang Grandegger <wg@grandegger.com>,
linux-can@vger.kernel.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 04/15] can: m_can: Use transmit event FIFO watermark level interrupt
Date: Tue, 13 Dec 2022 20:18:07 +0100 [thread overview]
Message-ID: <20221213191807.kdpfhh2eo5ujtqgq@pengutronix.de> (raw)
In-Reply-To: <20221213171946.ejrb2glgo77jueff@blmsp>
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On 13.12.2022 18:19:46, Markus Schneider-Pargmann wrote:
> Hi Marc,
>
> On Thu, Dec 01, 2022 at 05:59:53PM +0100, Markus Schneider-Pargmann wrote:
> > On Thu, Dec 01, 2022 at 12:00:33PM +0100, Marc Kleine-Budde wrote:
> > > On 01.12.2022 11:12:20, Markus Schneider-Pargmann wrote:
> > > > > > For the upcoming receive side patch I already added a hrtimer. I may try
> > > > > > to use the same timer for both directions as it is going to do the exact
> > > > > > same thing in both cases (call the interrupt routine). Of course that
> > > > > > depends on the details of the coalescing support. Any objections on
> > > > > > that?
> > > > >
> > > > > For the mcp251xfd I implemented the RX and TX coalescing independent of
> > > > > each other and made it configurable via ethtool's IRQ coalescing
> > > > > options.
> > > > >
> > > > > The hardware doesn't support any timeouts and only FIFO not empty, FIFO
> > > > > half full and FIFO full IRQs and the on chip RAM for mailboxes is rather
> > > > > limited. I think the mcan core has the same limitations.
> > > >
> > > > Yes and no, the mcan core provides watermark levels so it has more
> > > > options, but there is no hardware timer as well (at least I didn't see
> > > > anything usable).
> > >
> > > Are there any limitations to the water mark level?
> >
> > Anything specific? I can't really see any limitation. You can set the
> > watermark between 1 and 32. I guess we could also always use it instead
> > of the new-element interrupt, but I haven't tried that yet. That may
> > simplify the code.
>
> Just a quick comment here after trying this, I decided against it.
> - I can't modify the watermark levels once the chip is active.
> - Using interrupt (un)masking I can change the behavior for tx and rx
> with a single register write instead of two to the two fifo
> configuration registers.
Makes sense.
> You will see this in the second part of the series then.
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 |
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next prev parent reply other threads:[~2022-12-13 19:18 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-16 20:52 [PATCH 00/15] can: m_can: Optimizations for tcan and peripheral chips Markus Schneider-Pargmann
2022-11-16 20:52 ` [PATCH 01/15] can: m_can: Eliminate double read of TXFQS in tx_handler Markus Schneider-Pargmann
2022-11-16 20:52 ` [PATCH 02/15] can: m_can: Wakeup net queue once tx was issued Markus Schneider-Pargmann
2022-11-30 17:21 ` Marc Kleine-Budde
2022-12-01 8:43 ` Markus Schneider-Pargmann
2022-12-01 9:16 ` Marc Kleine-Budde
2022-12-01 16:49 ` Markus Schneider-Pargmann
2022-12-02 9:16 ` Marc Kleine-Budde
2022-12-14 9:14 ` Markus Schneider-Pargmann
2022-12-14 9:18 ` Marc Kleine-Budde
2022-12-14 9:22 ` Marc Kleine-Budde
2022-12-14 10:15 ` Vincent MAILHOL
2022-12-14 10:35 ` Markus Schneider-Pargmann
2022-12-15 9:31 ` Markus Schneider-Pargmann
2022-12-16 4:40 ` Vincent MAILHOL
2022-12-14 10:18 ` Markus Schneider-Pargmann
2022-12-02 13:53 ` Marc Kleine-Budde
2022-11-16 20:52 ` [PATCH 03/15] can: m_can: Cache tx putidx and transmits in flight Markus Schneider-Pargmann
2022-12-01 11:14 ` Marc Kleine-Budde
2022-12-02 8:37 ` Markus Schneider-Pargmann
2022-12-02 14:46 ` Marc Kleine-Budde
2022-12-13 17:13 ` Markus Schneider-Pargmann
2022-12-13 19:17 ` Marc Kleine-Budde
2022-12-14 8:32 ` Markus Schneider-Pargmann
2022-11-16 20:52 ` [PATCH 04/15] can: m_can: Use transmit event FIFO watermark level interrupt Markus Schneider-Pargmann
2022-11-30 17:17 ` Marc Kleine-Budde
2022-12-01 8:25 ` Markus Schneider-Pargmann
2022-12-01 9:05 ` Marc Kleine-Budde
2022-12-01 10:12 ` Markus Schneider-Pargmann
2022-12-01 11:00 ` Marc Kleine-Budde
2022-12-01 16:59 ` Markus Schneider-Pargmann
2022-12-02 9:23 ` Marc Kleine-Budde
2022-12-02 9:43 ` Markus Schneider-Pargmann
2022-12-02 14:03 ` Marc Kleine-Budde
2022-12-13 17:19 ` Markus Schneider-Pargmann
2022-12-13 19:18 ` Marc Kleine-Budde [this message]
2022-11-16 20:52 ` [PATCH 05/15] can: m_can: Disable unused interrupts Markus Schneider-Pargmann
2022-11-16 20:52 ` [PATCH 06/15] can: m_can: Avoid reading irqstatus twice Markus Schneider-Pargmann
2022-11-16 20:53 ` [PATCH 07/15] can: m_can: Read register PSR only on error Markus Schneider-Pargmann
2022-11-16 20:53 ` [PATCH 08/15] can: m_can: Count TXE FIFO getidx in the driver Markus Schneider-Pargmann
2022-11-16 20:53 ` [PATCH 09/15] can: m_can: Count read getindex " Markus Schneider-Pargmann
2022-11-16 20:53 ` [PATCH 10/15] can: m_can: Batch acknowledge rx fifo Markus Schneider-Pargmann
2022-11-16 20:53 ` [PATCH 11/15] can: m_can: Batch acknowledge transmit events Markus Schneider-Pargmann
2022-11-16 20:53 ` [PATCH 12/15] can: tcan4x5x: Remove invalid write in clear_interrupts Markus Schneider-Pargmann
2022-12-02 14:17 ` Marc Kleine-Budde
2022-11-16 20:53 ` [PATCH 13/15] can: tcan4x5x: Fix use of register error status mask Markus Schneider-Pargmann
2022-12-02 14:19 ` Marc Kleine-Budde
2022-11-16 20:53 ` [PATCH 14/15] can: tcan4x5x: Fix register range of first block Markus Schneider-Pargmann
2022-12-02 14:28 ` Marc Kleine-Budde
2022-12-05 9:30 ` Markus Schneider-Pargmann
2022-12-05 9:44 ` Marc Kleine-Budde
2022-12-05 9:55 ` Markus Schneider-Pargmann
2022-11-16 20:53 ` [PATCH 15/15] can: tcan4x5x: Specify separate read/write ranges Markus Schneider-Pargmann
2022-12-02 14:03 ` [PATCH 00/15] can: m_can: Optimizations for tcan and peripheral chips Marc Kleine-Budde
2022-12-05 9:09 ` Markus Schneider-Pargmann
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