From: Joakim Tjernlund <Joakim.Tjernlund@infinera.com>
To: "mpe@ellerman.id.au" <mpe@ellerman.id.au>,
"broonie@kernel.org" <broonie@kernel.org>,
"paulus@samba.org" <paulus@samba.org>,
"npiggin@gmail.com" <npiggin@gmail.com>,
"Chris.Packham@alliedtelesis.co.nz"
<Chris.Packham@alliedtelesis.co.nz>,
"benh@kernel.crashing.org" <benh@kernel.crashing.org>,
"hkallweit1@gmail.com" <hkallweit1@gmail.com>
Cc: "linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
"linux-spi@vger.kernel.org" <linux-spi@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: fsl_espi errors on v5.7.15
Date: Mon, 7 Sep 2020 15:38:37 +0000 [thread overview]
Message-ID: <a6bae2a775c3e6b9115a1371157404c4e0f8a73a.camel@infinera.com> (raw)
In-Reply-To: <23d13439e4cc1872c29db2f93e715a61f4843943.camel@infinera.com>
[SNIP]
> >
> > > Would you be able to ftrace the interrupt handler function and see if you
> > > can see a difference in number or timing of interrupts? I'm at a bit of
> > > a loss.
> >
> > I tried ftrace but I really wasn't sure what I was looking for.
> > Capturing a "bad" case was pretty tricky. But I think I've identified a
> > fix (I'll send it as a proper patch shortly). The gist is
> >
> > diff --git a/drivers/spi/spi-fsl-espi.c b/drivers/spi/spi-fsl-espi.c
> > index 7e7c92cafdbb..cb120b68c0e2 100644
> > --- a/drivers/spi/spi-fsl-espi.c
> > +++ b/drivers/spi/spi-fsl-espi.c
> > @@ -574,13 +574,14 @@ static void fsl_espi_cpu_irq(struct fsl_espi
> > *espi, u32 events)
> > static irqreturn_t fsl_espi_irq(s32 irq, void *context_data)
> > {
> > struct fsl_espi *espi = context_data;
> > - u32 events;
> > + u32 events, mask;
> >
> > spin_lock(&espi->lock);
> >
> > /* Get interrupt events(tx/rx) */
> > events = fsl_espi_read_reg(espi, ESPI_SPIE);
> > - if (!events) {
> > + mask = fsl_espi_read_reg(espi, ESPI_SPIM);
> > + if (!(events & mask)) {
> > spin_unlock(&espi->lock);
> > return IRQ_NONE;
> > }
> >
> > The SPIE register contains the TXCNT so events is pretty much always
> > going to have something set. By checking events against what we've
> > actually requested interrupts for we don't see any spurious events.
> >
> > I've tested this on the T2080RDB and on our custom hardware and it seems
> > to resolve the problem.
> >
>
> I looked at the fsl_espi_irq() too and noticed that clearing of the IRQ events
> are after processing TX/RX. That looks a bit odd to me.
I should have been more specific. I think you can loose IRQs as fsl_espi_irq() works now.
Consider this:
1) You get TX IRQ and enter fsl_espi_irq()
2) Enter fsl_espi_fill_tx_fifo() to process any chars until done.
3) Now you get one more TX IRQ
4) fsl_espi_irq() clear events -> IRQ from 3) is lost.
Jocke
next prev parent reply other threads:[~2020-09-07 15:43 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-14 2:48 fsl_espi errors on v5.7.15 Chris Packham
2020-08-14 6:19 ` Heiner Kallweit
2020-08-16 21:09 ` Chris Packham
2020-08-18 22:44 ` Chris Packham
2020-08-19 6:15 ` Heiner Kallweit
2020-08-19 21:08 ` Chris Packham
2020-08-24 22:04 ` Chris Packham
2020-08-25 3:54 ` Chris Packham
2020-08-25 7:22 ` Heiner Kallweit
2020-08-25 22:22 ` Chris Packham
2020-08-26 1:48 ` Chris Packham
2020-08-26 6:07 ` Chris Packham
2020-08-26 6:38 ` Heiner Kallweit
2020-08-26 22:26 ` Chris Packham
2020-08-27 7:12 ` Nicholas Piggin
2020-08-27 22:07 ` Chris Packham
2020-08-30 12:30 ` Nicholas Piggin
2020-08-30 13:55 ` Heiner Kallweit
2020-08-30 21:00 ` Chris Packham
2020-08-30 21:41 ` Heiner Kallweit
2020-08-30 21:59 ` Chris Packham
2020-08-31 12:33 ` Heiner Kallweit
2020-09-01 1:25 ` Chris Packham
2020-09-01 6:14 ` Nicholas Piggin
2020-09-01 23:29 ` Chris Packham
2020-09-01 23:31 ` Chris Packham
2020-09-03 23:58 ` Chris Packham
[not found] ` <CAFSsGVvRMQoEoBN1hpao_4uM1yF2wwuKPbMkAcwFWyE1X8HDbQ@mail.gmail.com>
2020-09-06 21:03 ` Chris Packham
2020-09-07 9:53 ` Joakim Tjernlund
2020-09-07 15:38 ` Joakim Tjernlund [this message]
2020-09-01 2:52 ` Chris Packham
2020-09-01 7:38 ` Heiner Kallweit
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