Visible to Intel only — GUID: der1676414039672
Ixiasoft
Visible to Intel only — GUID: der1676414039672
Ixiasoft
11.8.3.4. FPGA-to-HPS CCU to Peripherals (Device Non-Bufferable)
If your logic issues a device non-bufferable 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 merge with other transactions. All transactions from the same ID remain ordered.
For reads, cache is not looked up. Read data is returned directly from peripheral. The following table shows the 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:
|
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 |
For writes, cache is not looked up. Write data is stored directly to peripheral. The following table shows the 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:
|
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 |