| Message ID | 20180807085406.3863-3-marc.zyngier@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | iommu/rockchip: Runtime PM fixes | expand |
Am Dienstag, 7. August 2018, 10:54:06 CEST schrieb Marc Zyngier: > 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: 0f181d3cf7d98 ("iommu/rockchip: Add runtime PM support") > Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Heiko Stuebner <heiko@sntech.de>
diff --git a/drivers/iommu/rockchip-iommu.c b/drivers/iommu/rockchip-iommu.c index 4e0f9b61cd7f..2b1724e8d307 100644 --- a/drivers/iommu/rockchip-iommu.c +++ b/drivers/iommu/rockchip-iommu.c @@ -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);
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: 0f181d3cf7d98 ("iommu/rockchip: Add runtime PM support") Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> --- drivers/iommu/rockchip-iommu.c | 24 +++++++++++++----------- 1 file changed, 13 insertions(+), 11 deletions(-)