disable FB

hc

2024-01-04 1543e317f1da31b75942316931e8f491a8920811

 kernel/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
..
..
@@ -199,13 +199,27 @@
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 static int qcom_smmu_cfg_probe(struct arm_smmu_device *smmu)
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 {
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-	unsigned int last_s2cr = ARM_SMMU_GR0_S2CR(smmu->num_mapping_groups - 1);
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 	struct qcom_smmu *qsmmu = to_qcom_smmu(smmu);
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+	unsigned int last_s2cr;
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 	u32 reg;
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 	u32 smr;
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 	int i;
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 	/*
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+	 * Some platforms support more than the Arm SMMU architected maximum of
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+	 * 128 stream matching groups. For unknown reasons, the additional
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+	 * groups don't exhibit the same behavior as the architected registers,
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+	 * so limit the groups to 128 until the behavior is fixed for the other
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+	 * groups.
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+	 */
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+	if (smmu->num_mapping_groups > 128) {
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+		dev_notice(smmu->dev, "\tLimiting the stream matching groups to 128\n");
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+		smmu->num_mapping_groups = 128;
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+	}
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+
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+	last_s2cr = ARM_SMMU_GR0_S2CR(smmu->num_mapping_groups - 1);
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+
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+	/*
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 	 * With some firmware versions writes to S2CR of type FAULT are
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 	 * ignored, and writing BYPASS will end up written as FAULT in the
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 	 * register. Perform a write to S2CR to detect if this is the case and