Hi Rob,
<..>
>>>+++ b/Documentation/devicetree/bindings/iommu/qcom,iommu.txt
>>>@@ -0,0 +1,45 @@
>>>+* QCOM IOMMU Implementation
>>>+
>>>+Qualcomm "B" family devices which are not compatible with arm-smmu have
>>>+a similar looking IOMMU but without access to the global register space.
>>>+This is modelled as separate IOMMU devices which have just a single
>>>+master.
>>>+
>>>+** Required properties:
>>>+
>>>+- compatible : Should be one of:
>>>+
>>>+ "qcom,msm8916-iommu-context-bank"
>>>+
>>>+ depending on the particular implementation and/or the
>>>+ version of the architecture implemented.
>>>+
>>>+- reg : Base address and size of the SMMU. And optionally,
>>>+ if present, the "smmu_local_base"
>>>+
>>>+- interrupts : The context fault irq.
>>>+
>>>+- #iommu-cells : Must be 0
>>>+
>>>+- qcom,iommu-ctx-asid : context ASID
>>>+
>>>+- qcom,iommu-secure-id : secure-id
>>>+
>>>+- clocks : The interface clock (iface_clk) and bus clock (bus_clk)
>>>+
>>>+** Examples:
>>>+
>>>+ mdp_iommu: iommu-context-bank@1e24000 {
>>>+ compatible = "qcom,msm8916-iommu-context-bank";
>>>+ reg = <0x1e24000 0x1000
>>>+ 0x1ef0000 0x3000>;
>>>+ reg-names = "iommu_base", "smmu_local_base";
>>>+ interrupts = <GIC_SPI 70 0>;
>>>+ qcom,iommu-ctx-asid = <4>;
>>>+ qcom,iommu-secure-id = <17>;
>>
>> This is not an per context bank property and can be programmed for an
>> given iommu only once. So we call qcom_iommu_sec_init for
>> each context bank once, which does not look correct. Similarly for
>> smmu_local_base as well. So should this be handled using an global
>> once for all contexts ?
>
>yeah, smmu_local_base and secure-id would be duplicate for all context
>banks that are part of the same actual iommu. (But it was Robin's
>suggestion to just model this as separate context-bank devices, since
>we cannot touch the global space).
>
>Did I misunderstand the downstream driver code? It looked like
>qcom_scm_restore_sec_cfg() was called once on first attach per
>context-bank, not globally for the entire iommu, which is what I'm
>doing with this driver. But I haven't yet tried to enable other
>context-banks in the apps iommu yet.
>
The downstream driver seems to be calling the sec_cfg once
for an iommu when a context is attached for the first time and not for
the subsequent's contexts that are attached. So, means programmed
only once and not for every context. I see it that way. Anyways when you
add more than context-banks, we can see if that causes trouble..
Regards,
Sricharan
--
To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
