On some SoCs like MSM8956, MSM8976 and others, secure contexts are
also secured: these get programmed by the bootloader or TZ (as usual)
but their "interesting" registers are locked out by the hypervisor,
disallowing direct register writes from Linux and, in many cases,
completely disallowing the reprogramming of TTBR, TCR, MAIR and other
registers including, but not limited to, resetting contexts.
This is referred downstream as a "v2" IOMMU but this is effectively
a "v2 firmware configuration" instead.
Luckily, the described behavior of version 2 is effective only on
secure contexts and not on non-secure ones: add support for that,
finally getting a completely working IOMMU on at least MSM8956/76.
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>
---
drivers/iommu/arm/arm-smmu/qcom_iommu.c | 21 ++++++++++++++++++---
1 file changed, 18 insertions(+), 3 deletions(-)
diff --git a/drivers/iommu/arm/arm-smmu/qcom_iommu.c b/drivers/iommu/arm/arm-smmu/qcom_iommu.c
index 1fcee74154f0..bba5274bf8d4 100644
--- a/drivers/iommu/arm/arm-smmu/qcom_iommu.c
+++ b/drivers/iommu/arm/arm-smmu/qcom_iommu.c
@@ -59,6 +59,7 @@ struct qcom_iommu_ctx {
struct device *dev;
void __iomem *base;
bool secure_init;
+ bool secured_ctx;
u8 asid; /* asid and ctx bank # are 1:1 */
struct iommu_domain *domain;
};
@@ -287,6 +288,12 @@ static int qcom_iommu_init_domain(struct iommu_domain *domain,
ctx->secure_init = true;
}
+ /* Secured QSMMU-500/QSMMU-v2 contexts cannot be programmed */
+ if (ctx->secured_ctx) {
+ ctx->domain = domain;
+ continue;
+ }
+
qcom_iommu_reset_ctx(ctx);
/* TTBRs */
@@ -418,7 +425,8 @@ static void qcom_iommu_detach_dev(struct iommu_domain *domain, struct device *de
struct qcom_iommu_ctx *ctx = to_ctx(qcom_domain, fwspec->ids[i]);
/* Disable and reset the context bank */
- qcom_iommu_reset_ctx(ctx);
+ if (!ctx->secured_ctx)
+ qcom_iommu_reset_ctx(ctx);
ctx->domain = NULL;
}
@@ -699,10 +707,14 @@ static int qcom_iommu_ctx_probe(struct platform_device *pdev)
if (irq < 0)
return -ENODEV;
+ if (of_device_is_compatible(dev->of_node, "qcom,msm-iommu-v2-sec"))
+ ctx->secured_ctx = true;
+
/* clear IRQs before registering fault handler, just in case the
* boot-loader left us a surprise:
*/
- iommu_writel(ctx, ARM_SMMU_CB_FSR, iommu_readl(ctx, ARM_SMMU_CB_FSR));
+ if (!ctx->secured_ctx)
+ iommu_writel(ctx, ARM_SMMU_CB_FSR, iommu_readl(ctx, ARM_SMMU_CB_FSR));
ret = devm_request_irq(dev, irq,
qcom_iommu_fault,
@@ -744,6 +756,8 @@ static int qcom_iommu_ctx_remove(struct platform_device *pdev)
static const struct of_device_id ctx_of_match[] = {
{ .compatible = "qcom,msm-iommu-v1-ns" },
{ .compatible = "qcom,msm-iommu-v1-sec" },
+ { .compatible = "qcom,msm-iommu-v2-ns" },
+ { .compatible = "qcom,msm-iommu-v2-sec" },
{ /* sentinel */ }
};
@@ -761,7 +775,8 @@ static bool qcom_iommu_has_secure_context(struct qcom_iommu_dev *qcom_iommu)
struct device_node *child;
for_each_child_of_node(qcom_iommu->dev->of_node, child) {
- if (of_device_is_compatible(child, "qcom,msm-iommu-v1-sec")) {
+ if (of_device_is_compatible(child, "qcom,msm-iommu-v1-sec") ||
+ of_device_is_compatible(child, "qcom,msm-iommu-v2-sec")) {
of_node_put(child);
return true;
}
--
2.38.1
