From: Mark Brown <broonie@kernel.org>
To: Baolin Wang <baolin.wang@linaro.org>
Cc: robh+dt@kernel.org, mark.rutland@arm.com, orsonzhai@gmail.com,
zhang.lyra@gmail.com, lanqing.liu@unisoc.com,
linux-spi@vger.kernel.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/4] spi: sprd: Add the SPI irq function for the SPI DMA mode
Date: Tue, 15 Jan 2019 14:24:52 +0000 [thread overview]
Message-ID: <20190115142452.GA5522@sirena.org.uk> (raw)
In-Reply-To: <ec1741f29c44c436c1086877ff5b208e6b8af45d.1547559542.git.baolin.wang@linaro.org>
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On Tue, Jan 15, 2019 at 09:46:51PM +0800, Baolin Wang wrote:
This looks good, just one small issue and a thing to check:
> +static irqreturn_t sprd_spi_handle_irq(int irq, void *data)
> +{
> + struct sprd_spi *ss = (struct sprd_spi *)data;
> + u32 val = readl_relaxed(ss->base + SPRD_SPI_INT_MASK_STS);
> +
> + if (val & SPRD_SPI_MASK_TX_END) {
> + writel_relaxed(SPRD_SPI_TX_END_CLR, ss->base + SPRD_SPI_INT_CLR);
> + if (!(ss->trans_mode & SPRD_SPI_RX_MODE))
> + complete(&ss->xfer_completion);
> + return IRQ_HANDLED;
> + }
> +
> + if (val & SPRD_SPI_MASK_RX_END) {
> + writel_relaxed(SPRD_SPI_RX_END_CLR, ss->base + SPRD_SPI_INT_CLR);
> + complete(&ss->xfer_completion);
> + }
> +
> + return IRQ_HANDLED;
> +}
This will return IRQ_HANDLED no matter if there was an interrupt
actually handled. That means that if something goes wrong due to some
bug or a hardware change (eg, a new version of the IP) and there's
another interrupt fired we won't clear it and the interrupt core won't
be able to detect that it's a spurious interrupt and use its own error
handling. It's better to return IRQ_NONE in that case.
> + ret = devm_request_irq(&pdev->dev, ss->irq, sprd_spi_handle_irq,
> + 0, pdev->name, ss);
> + if (ret)
> + dev_err(&pdev->dev, "failed to request spi irq %d, ret = %d\n",
> + ss->irq, ret);
Are you sure it's safe to use devm_request_irq(), especially when
unloading the driver? Using it means that we will only disable the
interrupt after the driver's remove function has finished so there's a
danger of an interrupt firing when some of the resources the hander has
used are still in use. I didn't spot any issues, just something to
check especially with the later patches building on top of this.
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next prev parent reply other threads:[~2019-01-15 14:25 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-15 13:46 [PATCH 1/4] spi: sprd: Fix the error data length in SPI read-only mode Baolin Wang
2019-01-15 13:46 ` [PATCH 2/4] spi: sprd: Add the SPI irq function for the SPI DMA mode Baolin Wang
2019-01-15 14:24 ` Mark Brown [this message]
2019-01-16 2:21 ` Baolin Wang
2019-01-15 13:46 ` [PATCH 3/4] dt-bindings: spi: Add the DMA properties for the SPI dma mode Baolin Wang
2019-01-21 13:52 ` Rob Herring
2019-01-22 2:22 ` Baolin Wang
2019-01-22 8:11 ` Geert Uytterhoeven
2019-01-22 8:43 ` Baolin Wang
2019-01-15 13:46 ` [PATCH 4/4] spi: sprd: Add DMA mode support Baolin Wang
2019-01-15 14:30 ` Mark Brown
2019-01-16 2:34 ` Baolin Wang
2019-01-15 19:08 ` Applied "spi: sprd: Fix the error data length in SPI read-only mode" to the spi tree Mark Brown
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