From 8d8d3752c0a4f7fb072352837cbdbf57c02df239 Mon Sep 17 00:00:00 2001 From: Xu Lu Date: Fri, 3 Jan 2025 17:32:19 +0800 Subject: [PATCH] iommu/riscv: Empty iommu queue before enabling it Changing cqen/fqen/pqen from 0 to 1 sets the cqh/fqt/pqt registers to 0. But the cqt/fqh/pqh registers are left unmodified. This commit resets cqt/fqh/pqh registers to ensure corresponding queues are empty before being enabled during initialization. Signed-off-by: Xu Lu Link: https://lore.kernel.org/r/20250103093220.38106-2-luxu.kernel@bytedance.com Signed-off-by: Joerg Roedel --- drivers/iommu/riscv/iommu.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/iommu/riscv/iommu.c b/drivers/iommu/riscv/iommu.c index 8a05def774bd..84806724f568 100644 --- a/drivers/iommu/riscv/iommu.c +++ b/drivers/iommu/riscv/iommu.c @@ -240,6 +240,12 @@ static int riscv_iommu_queue_enable(struct riscv_iommu_device *iommu, return rc; } + /* Empty queue before enabling it */ + if (queue->qid == RISCV_IOMMU_INTR_CQ) + riscv_iommu_writel(queue->iommu, Q_TAIL(queue), 0); + else + riscv_iommu_writel(queue->iommu, Q_HEAD(queue), 0); + /* * Enable queue with interrupts, clear any memory fault if any. * Wait for the hardware to acknowledge request and activate queue -- 2.50.1