From: Vladimir Oltean <olteanv@gmail.com>
To: Mark Brown <broonie@kernel.org>
Cc: Marc Kleine-Budde <mkl@pengutronix.de>,
Krzysztof Kozlowski <krzk@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Vladimir Oltean <vladimir.oltean@nxp.com>,
linux-spi <linux-spi@vger.kernel.org>,
lkml <linux-kernel@vger.kernel.org>,
Wolfram Sang <wsa@kernel.org>,
stable@vger.kernel.org,
Pengutronix Kernel Team <kernel@pengutronix.de>
Subject: Re: [PATCH v2 1/3] spi: spi-fsl-dspi: Fix external abort on interrupt in exit paths
Date: Mon, 15 Jun 2020 15:56:01 +0300 [thread overview]
Message-ID: <CA+h21hqC7hAenifvRqbwss=Sr+dAu3H9Dx=UF0TS0WVbkzTj2Q@mail.gmail.com> (raw)
In-Reply-To: <20200615123052.GO4447@sirena.org.uk>
On Mon, 15 Jun 2020 at 15:35, Mark Brown <broonie@kernel.org> wrote:
>
>
> Indeed. The upshot of all this is that the interrupt needs to be freed
> not disabled before the clocks are disabled, or some other mechanism
> needs to be used to ensure that the interrupt handler won't attempt to
> access the hardware when it shouldn't. As Vladimir says there are
> serious issues using devm for interrupt handlers (or anything else that
> might cause code to be run) due to problems like this.
And the down-shot is that whatever is done in dspi_remove (free_irq)
also needs to be done in dspi_suspend, but with extra care in
dspi_resume not only to request the irq again, but also to flush the
module's FIFOs and clear interrupts, because there might have been
nasty stuff uncaught during sleep:
regmap_update_bits(dspi->regmap, SPI_MCR,
SPI_MCR_CLR_TXF | SPI_MCR_CLR_RXF,
SPI_MCR_CLR_TXF | SPI_MCR_CLR_RXF);
regmap_write(dspi->regmap, SPI_SR, SPI_SR_CLEAR);
So it's pretty messy.
-Vladimir
next prev parent reply other threads:[~2020-06-15 12:56 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-15 8:07 [PATCH v2 1/3] spi: spi-fsl-dspi: Fix external abort on interrupt in exit paths Krzysztof Kozlowski
2020-06-15 8:07 ` [PATCH v2 2/3] spi: spi-fsl-dspi: Initialize completion before possible interrupt Krzysztof Kozlowski
2020-06-15 8:07 ` [PATCH v2 3/3] genirq: Do not test disabled IRQs with DEBUG_SHIRQ Krzysztof Kozlowski
2020-06-15 12:08 ` Mark Brown
2020-06-16 10:11 ` Krzysztof Kozlowski
2020-06-16 10:39 ` Mark Brown
2020-06-17 9:30 ` Thomas Gleixner
2020-06-15 8:17 ` [PATCH v2 1/3] spi: spi-fsl-dspi: Fix external abort on interrupt in exit paths Marc Kleine-Budde
2020-06-15 9:23 ` Vladimir Oltean
2020-06-15 13:08 ` Krzysztof Kozlowski
2020-06-15 12:30 ` Mark Brown
2020-06-15 12:56 ` Vladimir Oltean [this message]
2020-06-15 13:10 ` Mark Brown
2020-06-15 13:12 ` Vladimir Oltean
2020-06-15 13:24 ` Mark Brown
2020-06-15 13:29 ` Vladimir Oltean
2020-06-15 13:36 ` Mark Brown
2020-06-15 13:41 ` Krzysztof Kozlowski
2020-06-15 14:23 ` Vladimir Oltean
2020-06-15 14:57 ` Krzysztof Kozlowski
2020-06-15 14:59 ` Vladimir Oltean
2020-06-15 13:10 ` Krzysztof Kozlowski
2020-06-15 13:14 ` Vladimir Oltean
2020-06-15 13:28 ` Krzysztof Kozlowski
2020-06-15 13:33 ` Vladimir Oltean
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