Commit 8d8d3752 authored by Xu Lu's avatar Xu Lu Committed by Joerg Roedel
Browse files

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: default avatarXu Lu <luxu.kernel@bytedance.com>
Link: https://lore.kernel.org/r/20250103093220.38106-2-luxu.kernel@bytedance.com


Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
parent d5f88acd

drivers/iommu/riscv/iommu.c

+6 −0
Original line number Diff line number Diff line
@@ -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