[PATCH 3/3] iommu/arm-smmu: Error out only if not enough context interrupts
From: Will Deacon <hidden>
Date: 2018-07-24 08:36:38
Also in:
linux-arm-msm, linux-devicetree, linux-iommu, lkml
Subsystem:
iommu subsystem, the rest · Maintainers:
Joerg Roedel, Will Deacon, Linus Torvalds
On Thu, Jul 19, 2018 at 11:23:56PM +0530, Vivek Gautam wrote:
quoted hunk ↗ jump to hunk
Currently we check if the number of context banks is not equal to num_context_interrupts. However, there are booloaders such as, one on sdm845 that reserves few context banks and thus kernel views less than the total available context banks. So, although the hardware definition in device tree would mention the correct number of context interrupts, this number can be greater than the number of context banks visible to smmu in kernel. We should therefore error out only when the number of context banks is greater than the available number of context interrupts. Signed-off-by: Vivek Gautam <redacted> Suggested-by: Tomasz Figa <tfiga@chromium.org> Cc: Robin Murphy <robin.murphy@arm.com> Cc: Will Deacon <redacted> --- drivers/iommu/arm-smmu.c | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-)diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c index 7c69736a30f8..4cb53bf4f423 100644 --- a/drivers/iommu/arm-smmu.c +++ b/drivers/iommu/arm-smmu.c@@ -2229,12 +2229,19 @@ static int arm_smmu_device_probe(struct platform_device *pdev) if (err) return err; - if (smmu->version == ARM_SMMU_V2 && - smmu->num_context_banks != smmu->num_context_irqs) { - dev_err(dev, - "found only %d context interrupt(s) but %d required\n", - smmu->num_context_irqs, smmu->num_context_banks); - return -ENODEV; + if (smmu->version == ARM_SMMU_V2) { + if (smmu->num_context_banks > smmu->num_context_irqs) { + dev_err(dev, + "found only %d context irq(s) but %d required\n", + smmu->num_context_irqs, smmu->num_context_banks); + return -ENODEV; + } else if (smmu->num_context_banks < smmu->num_context_irqs) { + /* loose extra context interrupts */ + dev_notice(dev, + "found %d context irq(s) but only %d required\n", + smmu->num_context_irqs, smmu->num_context_banks); + smmu->num_context_irqs = smmu->num_context_banks; + }
I don't see the utility in the new message. Can you simplify with the patch below on top? It's a bit weird that we only decide to ignore the extra irqs after calling platform_get_irq() on them, but that seems to be harmless. Will --->8
diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index aa46c1ed5bf9..5349e22b5c78 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c@@ -2109,13 +2109,10 @@ static int arm_smmu_device_probe(struct platform_device *pdev) "found only %d context irq(s) but %d required\n", smmu->num_context_irqs, smmu->num_context_banks); return -ENODEV; - } else if (smmu->num_context_banks < smmu->num_context_irqs) { - /* loose extra context interrupts */ - dev_notice(dev, - "found %d context irq(s) but only %d required\n", - smmu->num_context_irqs, smmu->num_context_banks); - smmu->num_context_irqs = smmu->num_context_banks; } + + /* Ignore superfluous interrupts */ + smmu->num_context_irqs = smmu->num_context_banks; } for (i = 0; i < smmu->num_global_irqs; ++i) {