[PATCH 5.10 234/406] iommu/qcom: Disable and reset context bank before programming

Greg Kroah-Hartman
2023-09-17T19:33:47Z

From: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>

[ Upstream commit 9f3fef23d9b5a858a6e6d5f478bb1b6b76265e76 ]

Writing the new TTBRs, TCRs and MAIRs on a previously enabled
context bank may trigger a context fault, resulting in firmware
driven AP resets: change the domain initialization programming
sequence to disable the context bank(s) and to also clear the
related fault address (CB_FAR) and fault status (CB_FSR)
registers before writing new values to TTBR0/1, TCR/TCR2, MAIR0/1.

Fixes: 0ae349a0f33f ("iommu/qcom: Add qcom_iommu")
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Link: https://lore.kernel.org/r/20230622092742.74819-4-angelogioacchino.delregno@collabora.com
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/iommu/arm/arm-smmu/qcom_iommu.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/drivers/iommu/arm/arm-smmu/qcom_iommu.c b/drivers/iommu/arm/arm-smmu/qcom_iommu.c
index a24390c548a91..37c8f75a35801 100644
--- a/drivers/iommu/arm/arm-smmu/qcom_iommu.c
+++ b/drivers/iommu/arm/arm-smmu/qcom_iommu.c
@@ -283,6 +283,13 @@ static int qcom_iommu_init_domain(struct iommu_domain *domain,
ctx->secure_init = true;
}

+ /* Disable context bank before programming */
+ iommu_writel(ctx, ARM_SMMU_CB_SCTLR, 0);
+
+ /* Clear context bank fault address fault status registers */
+ iommu_writel(ctx, ARM_SMMU_CB_FAR, 0);
+ iommu_writel(ctx, ARM_SMMU_CB_FSR, ARM_SMMU_FSR_FAULT);
+
/* TTBRs */
iommu_writeq(ctx, ARM_SMMU_CB_TTBR0,
pgtbl_cfg.arm_lpae_s1_cfg.ttbr |
--
2.40.1