[PATCH v9 04/12] iommu/tegra241-cmdqv: Restore PROD and CONS after resume

[Pranjal Shrivastava]

From: Ashish Mhetre <amhetre at nvidia.com>

PROD and CONS indices for vcmdqs are getting set to 0 after resume.
Because of this the vcmdq is not consuming commands after resume.
Fix this by restoring PROD and CONS indices after resume from
saved pointers.

Reviewed-by: Nicolin Chen <nicolinc at nvidia.com>
Signed-off-by: Ashish Mhetre <amhetre at nvidia.com>
Signed-off-by: Pranjal Shrivastava <praan at google.com>
---
 drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c b/drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c
index f62e9bdabf8a..8ecd2052b6dd 100644
--- a/drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c
+++ b/drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c
@@ -553,6 +553,13 @@ static int tegra241_vcmdq_hw_init(struct tegra241_vcmdq *vcmdq)
 	/* Configure and enable VCMDQ */
 	writeq_relaxed(vcmdq->cmdq.q.q_base, REG_VCMDQ_PAGE1(vcmdq, BASE));
 
+	/*
+	 * HW Registers reset to 0 when power-cycled. Restore them from their
+	 * SW copies to prevent executing stale/ghost commands after resume.
+	 */
+	writel_relaxed(vcmdq->cmdq.q.llq.prod, REG_VCMDQ_PAGE0(vcmdq, PROD));
+	writel_relaxed(vcmdq->cmdq.q.llq.cons, REG_VCMDQ_PAGE0(vcmdq, CONS));
+
 	ret = vcmdq_write_config(vcmdq, VCMDQ_EN);
 	if (ret) {
 		dev_err(vcmdq->cmdqv->dev,
-- 
2.55.0.487.gaf234c4eb3-goog