From fcf226f1f7083cba76af47bf8dd764b68b149cd2 Mon Sep 17 00:00:00 2001 From: AngeloGioacchino Del Regno Date: Thu, 22 Jun 2023 11:27:38 +0200 Subject: [PATCH] iommu/qcom: Use the asid read from device-tree if specified As specified in this driver, the context banks are 0x1000 apart but on some SoCs the context number does not necessarily match this logic, hence we end up using the wrong ASID: keeping in mind that this IOMMU implementation relies heavily on SCM (TZ) calls, it is mandatory that we communicate the right context number. Since this is all about how context banks are mapped in firmware, which may be board dependent (as a different firmware version may eventually change the expected context bank numbers), introduce a new property "qcom,ctx-asid": when found, the ASID will be forced as read from the devicetree. When "qcom,ctx-asid" is not found, this driver retains the previous behavior as to avoid breaking older devicetrees or systems that do not require forcing ASID numbers. Signed-off-by: Marijn Suijten [Marijn: Rebased over next-20221111] Signed-off-by: AngeloGioacchino Del Regno Reviewed-by: Konrad Dybcio Link: https://lore.kernel.org/r/20230622092742.74819-3-angelogioacchino.delregno@collabora.com Signed-off-by: Will Deacon --- drivers/iommu/arm/arm-smmu/qcom_iommu.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) diff --git a/drivers/iommu/arm/arm-smmu/qcom_iommu.c b/drivers/iommu/arm/arm-smmu/qcom_iommu.c index abf7981..8c717bc 100644 --- a/drivers/iommu/arm/arm-smmu/qcom_iommu.c +++ b/drivers/iommu/arm/arm-smmu/qcom_iommu.c @@ -531,7 +531,8 @@ static int qcom_iommu_of_xlate(struct device *dev, struct of_phandle_args *args) * index into qcom_iommu->ctxs: */ if (WARN_ON(asid < 1) || - WARN_ON(asid > qcom_iommu->num_ctxs)) { + WARN_ON(asid > qcom_iommu->num_ctxs) || + WARN_ON(qcom_iommu->ctxs[asid - 1] == NULL)) { put_device(&iommu_pdev->dev); return -EINVAL; } @@ -617,7 +618,8 @@ free_mem: static int get_asid(const struct device_node *np) { - u32 reg; + u32 reg, val; + int asid; /* read the "reg" property directly to get the relative address * of the context bank, and calculate the asid from that: @@ -625,7 +627,17 @@ static int get_asid(const struct device_node *np) if (of_property_read_u32_index(np, "reg", 0, ®)) return -ENODEV; - return reg / 0x1000; /* context banks are 0x1000 apart */ + /* + * Context banks are 0x1000 apart but, in some cases, the ASID + * number doesn't match to this logic and needs to be passed + * from the DT configuration explicitly. + */ + if (!of_property_read_u32(np, "qcom,ctx-asid", &val)) + asid = val; + else + asid = reg / 0x1000; + + return asid; } static int qcom_iommu_ctx_probe(struct platform_device *pdev) -- 2.7.4