3.8.6. TBU QoS registers

The SMMU_TBUQOSx (where x = 0, 1, 2, or 3) registers characteristics are:


Specify the QoS for TBUs.


Available in all MMU-500 configurations.

Usage constraints

The types of registers are as follows:

TBU QoS register 0

Used when the TBUn is in the range 0-7.

TBU QoS register 1

Used when the TBUn is in the range 8-15.

TBU QoS register 2

Used when the TBUn is in the range 16-23.

TBU QoS register 3

Used when the TBUn is in the range 24-31.


Figure 3.15 shows the bit assignments.

Figure 3.15. SMMU_TBUQOSx registers bit assignments

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Table 3.27 shows the bit assignments.

Table 3.27. SMMU_TBUQOSx registers bit assignments

BitsName Reset valueDescription

The QoS for value at index i for TBUn is calculated by the following equation:

  • i = ((4 * p)+3) : (4*p)

    Where p is the number of TBUs. If the value of n is between 0-7, then p=n. Otherwise, p= (n%8).

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