Intel® Agilex™ Hard Processor System Technical Reference Manual

ID 683567
Date 11/11/2022
Public

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7.3.5.4. FPGA-to-HPS CCU to Peripherals (Device Non-Bufferable)

If your logic issues a Device Non-Buffereable transaction, write responses and read data are obtained from the final destination. Reads are not prefetched and writes are not merged. All transactions are non-modifiable, which means each transaction does not split into multiple transactions or merged with other transactions. All transactions from the same ID remains ordered.

Reads

  • Read data returned directly from peripheral. Cache is not looked up.
Table 75.  Read Data Attribute List
ATTRIBUTE VALUE NOTE
ARDOMAIN[1:0] ’b01 Inner Sharable
ARBAR[1:0] ‘b00 Normal access, respecting barriers
ARSNOOP[3:0] ‘b0000 ReadOnce
ARCACHE[3:0] ‘b0000 Device Non-bufferable
AxUSER[7:0] ‘b00000100 0x04 = CCU
AxPROT[2:0] ‘b001 Data access. Secure access. Privileged access.
AxLEN[7:0]
The burst length for:
  • WRAP burst type must be 1, 2, 4, 8 or 16 transfers.
  • INCR burst type is 1 to 256 transfers.
AxSIZE[2:0] The number of bytes in a transfer must be equal to the data bus width
AxBURST[1:0] ‘b01 or ‘b10 Must be INCR(‘b01) or WRAP(‘b10)
AxLOCK[1:0] ‘b00 Must be normal access
AxQOS Do not care

Writes

  • Write data is stored directly to peripheral. Cache is not looked up.
Table 76.  Write Data Attribute List
ATTRIBUTE VALUE NOTE
AWDOMAIN[1:0] ’b01 Inner Sharable
AWBAR[1:0] ‘b00 Normal access, respecting barriers
AWSNOOP[2:0] ‘b000 WriteUnique (could be ‘b001 for WriteLineUnique)
AWCACHE[3:0] ‘b0000 Device Non-Bufferable
AxUSER[7:0] ‘b00000100 0x04 = CCU
AxPROT[2:0] ‘b001 Data access. Secure access. Privileged access.
AxLEN[7:0]
The burst length for:
  • WRAP burst type must be 1, 2, 4, 8 or 16 transfers.
  • INCR burst type is 1 to 256 transfers.
AxSIZE[2:0] The number of bytes in a transfer must be equal to the data bus width
AxBURST[1:0] ‘b01 or ‘b10 Must be INCR(‘b01) or WRAP(‘b10)
AxLOCK[1:0] ‘b00 Must be normal access
AxQOS Do not care