From: Felipe Balbi <balbi@ti.com>
To: Mark Brown <broonie@kernel.org>
Cc: Sourav Poddar <sourav.poddar@ti.com>,
<spi-devel-general@lists.sourceforge.net>,
<grant.likely@linaro.org>, <balbi@ti.com>, <rnayak@ti.com>,
<linux-omap@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCHv4 2/3] drivers: spi: Add qspi flash controller
Date: Thu, 18 Jul 2013 16:31:58 +0300 [thread overview]
Message-ID: <20130718133158.GA1628@arwen.pp.htv.fi> (raw)
In-Reply-To: <20130718131822.GN22506@sirena.org.uk>
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Hi,
On Thu, Jul 18, 2013 at 02:18:22PM +0100, Mark Brown wrote:
> > >>+static irqreturn_t ti_qspi_isr(int irq, void *dev_id)
> > >>+{
> > >>+ struct ti_qspi *qspi = dev_id;
> > >>+ u16 mask, stat;
> > >>+
> > >>+ irqreturn_t ret = IRQ_HANDLED;
> > >>+
> > >>+ spin_lock(&qspi->lock);
> > >>+
> > >>+ stat = ti_qspi_readl(qspi, QSPI_SPI_STATUS_REG);
> > >>+ mask = ti_qspi_readl(qspi, QSPI_INTR_ENABLE_SET_REG);
> > >>+
> > >>+ if (stat&& mask)
> > >>+ ret = IRQ_WAKE_THREAD;
> > >>+
> > >>+ spin_unlock(&qspi->lock);
> > >>+
> > >>+ return ret;
>
> > >According to the above code we might interrupt for masked events...
> > >that's a bit worrying isn't it?
>
> > Yes, there is WC interrupt enable bit which enables the interrupt.
> > This interrupt
> > gets disabled by writing to the CLEAR reg in the threaded irq.
>
> So why do we report that we handled the interrupt then? Shouldn't we at
> least warn if we're getting spurious IRQs?
not spurious. OMAP has two sets of IRQ status registers. One is call
IRQSTATUS$n (n = 0, 1, ...) and IRQSTATUS_RAW$n.
IRQSTATUS$n will only enable the bits which fired IRQs and aren't
masked while IRQSTATUS_RAW$n will also enable the bits which are masked.
I could never come up with a use case where we would need to handle IRQs
which we decided to mask, but perhaps there might be some cases, I don't
know.
Based on that, I believe Sourav is reading IRQSTATUS_RAW$n, then he need
to clear the masked bits.
--
balbi
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next prev parent reply other threads:[~2013-07-18 13:32 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-18 10:01 [PATCH 0/3] spi changes and ti quad spi controller Sourav Poddar
2013-07-18 10:01 ` [RFC/PATCHv2 1/3] driver: spi: Modify core to compute the message length Sourav Poddar
2013-07-18 15:22 ` Mark Brown
2013-07-18 10:01 ` [PATCHv4 2/3] drivers: spi: Add qspi flash controller Sourav Poddar
2013-07-18 10:24 ` Felipe Balbi
2013-07-18 11:18 ` Sourav Poddar
2013-07-18 11:24 ` Felipe Balbi
2013-07-18 12:24 ` Sourav Poddar
2013-07-19 11:48 ` Sourav Poddar
2013-07-19 12:20 ` Felipe Balbi
2013-07-18 10:42 ` Mark Brown
2013-07-18 11:45 ` Sourav Poddar
2013-07-18 11:56 ` Felipe Balbi
2013-07-18 13:18 ` Mark Brown
2013-07-18 13:31 ` Felipe Balbi [this message]
2013-07-18 14:42 ` Mark Brown
2013-07-18 14:55 ` Sourav Poddar
2013-07-18 15:28 ` Mark Brown
2013-07-19 11:55 ` Sourav Poddar
2013-07-18 19:08 ` Trent Piepho
2013-07-18 20:39 ` Mark Brown
2013-07-18 20:59 ` Nishanth Menon
2013-07-19 5:02 ` Sourav Poddar
2013-07-18 10:01 ` [RFC/PATCHv2 3/3] driver: spi: Add quad spi read support Sourav Poddar
2013-07-18 10:44 ` Mark Brown
2013-07-18 11:52 ` Sourav Poddar
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