ARM SMMU versions 1 and 2: Difference between revisions
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=== Number of supported Contexts === |
=== Number of supported Contexts === |
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The max number of supported contexts is implied by the max number of |
The max number of supported contexts is implied by the max number of SMMU_CBARn registers (Section 2.3.4: "The number of SMMU_CBARn regs matches the number of entries in the translation context bank table, and is IMPLEMENTATION DEFINED. SMMU_IDR1.NUMCB specifies the number of implemented SMMU_CBARn regs."). That said, NUMCB is an 8-bit field, and section 2.6.1 says: "The SMMU architecture provides space for up to 128 translation context banks". |
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* Multiple SMMU_SMRn regs may cause multiple StreamIDs to map to the same Context when Stream Matching is used. |
* Multiple SMMU_SMRn regs may cause multiple StreamIDs to map to the same Context when Stream Matching is used. |
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The SMMU is allowed to prefetch the translation tables pointed to by a context bank if that context bank is pointed to by an entry in the Stream Mapping table. This is permitted even if there is no client transaction which is using/ has used that translation (section 2.5.1). |
The SMMU is allowed to prefetch the translation tables pointed to by a context bank if that context bank is pointed to by an entry in the Stream Mapping table. This is permitted even if there is no client transaction which is using/ has used that translation (section 2.5.1). |
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== Context banks == |
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Each context bank is one page large, where "one page" is defined as PAGESIZE which may be either 4KiB or 64KiB. The intention is that a hypervisor can |
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