Commit 1aa55ca9 authored Aug 24, 2018 by Marc Zyngier Committed by Olof Johansson Aug 24, 2018

iommu/rockchip: Move irq request past pm_runtime_enable



Enabling the interrupt early, before power has been applied to the
device, can result in an interrupt being delivered too early if:

- the IOMMU shares an interrupt with a VOP
- the VOP has a pending interrupt (after a kexec, for example)

In these conditions, we end-up taking the interrupt without
the IOMMU being ready to handle the interrupt (not powered on).

Moving the interrupt request past the pm_runtime_enable() call
makes sure we can at least access the IOMMU registers. Note that
this is only a partial fix, and that the VOP interrupt will still
be screaming until the VOP driver kicks in, which advocates for
a more synchronized interrupt enabling/disabling approach.

Fixes: 0f181d3c ("iommu/rockchip: Add runtime PM support")
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Olof Johansson <olof@lixom.net>

parent 3fc7c5c0

drivers/iommu/rockchip-iommu.c

+13 −11

Original line number	Diff line number	Diff line
		@@ -1161,17 +1161,6 @@ static int rk_iommu_probe(struct platform_device *pdev)
		if (iommu->num_mmu == 0)
		return PTR_ERR(iommu->bases[0]);

		i = 0;
		while ((irq = platform_get_irq(pdev, i++)) != -ENXIO) {
		if (irq < 0)
		return irq;

		err = devm_request_irq(iommu->dev, irq, rk_iommu_irq,
		IRQF_SHARED, dev_name(dev), iommu);
		if (err)
		return err;
		}

		iommu->reset_disabled = device_property_read_bool(dev,
		"rockchip,disable-mmu-reset");

		@@ -1228,6 +1217,19 @@ static int rk_iommu_probe(struct platform_device *pdev)

		pm_runtime_enable(dev);

		i = 0;
		while ((irq = platform_get_irq(pdev, i++)) != -ENXIO) {
		if (irq < 0)
		return irq;

		err = devm_request_irq(iommu->dev, irq, rk_iommu_irq,
		IRQF_SHARED, dev_name(dev), iommu);
		if (err) {
		pm_runtime_disable(dev);
		goto err_remove_sysfs;
		}
		}

		return 0;
		err_remove_sysfs:
		iommu_device_sysfs_remove(&iommu->iommu);