[PATCH v11 09/16] iommu/arm-smmu-v3: Restore MSI config on resume
WARM2d
REVIEWED: 2 (1M)
From: Pranjal Shrivastava <praan@google.com>
Date: 2026-09-29 03:45:42
Also in:
driver-core, linux-iommu, linux-pci, lkml
Subsystem:
arm smmu drivers, iommu subsystem, the rest · Maintainers:
Will Deacon, Joerg Roedel, Linus Torvalds
Revision v11 of 5 in this series; 2 review trailers.
Revisions (5)
The SMMU's MSI configuration registers (*_IRQ_CFGn) containing target address, data and memory attributes lose their state when the SMMU is powered down. Introduce arm_smmu_resume_msis() to zero the *_IRQ_CFG0 registers (which reset to unknown values) and restore the cached MSI messages across the device's MSI domain via msi_device_domain_restore_msi_msgs(). In addition, clear ARM_SMMU_FEAT_MSI if MSI setup fails and the driver falls back to wired IRQs, preventing spurious MSI resume attempts. Reviewed-by: Nicolin Chen <redacted> Reviewed-by: Mostafa Saleh <smostafa@google.com> Signed-off-by: Pranjal Shrivastava <praan@google.com> --- drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 13 +++++++++++++ 1 file changed, 13 insertions(+)
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index dc2fc02b5163..7347d3ecdae8 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c@@ -4779,6 +4779,19 @@ static void arm_smmu_write_msi_msg(struct msi_desc *desc, struct msi_msg *msg) writel_relaxed(ARM_SMMU_MEMATTR_DEVICE_nGnRE, smmu->base + cfg[2]); } +static void __maybe_unused arm_smmu_resume_msis(struct arm_smmu_device *smmu) +{ + /* Clear the MSI address regs as they reset to unknown value */ + writeq_relaxed(0, smmu->base + ARM_SMMU_GERROR_IRQ_CFG0); + writeq_relaxed(0, smmu->base + ARM_SMMU_EVTQ_IRQ_CFG0); + + if (smmu->features & ARM_SMMU_FEAT_PRI) + writeq_relaxed(0, smmu->base + ARM_SMMU_PRIQ_IRQ_CFG0); + + /* No-op if no MSI device domain was instantiated (e.g. wired IRQs) */ + msi_device_domain_restore_msi_msgs(smmu->dev, MSI_DEFAULT_DOMAIN); +} + static void arm_smmu_setup_msis(struct arm_smmu_device *smmu) { int ret, nvec = ARM_SMMU_MAX_MSIS;
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2.56.0.rc1.315.gc6ed9934b7-goog