MIPI D-PHY IP User Guide: Agilex™ 5 FPGAs

ID 817561
Date 4/01/2024
Public

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6.1.6. AXI-Lite CSR Access

The D-PHY IP has a single AXI-Lite bus that allows the protocol agent in the fabric to access the CSR of the D-PHY.

Multiple links are accessed from the same AXI-Lite interface using the memory map described below. Aside from allowing access to the D-PHY internal IP registers, the AXI-Lite bus is designed to allow access to external registers which are used for accessing the PPI TG.

Table 27.  D-PHY IP Register Map
Start End Link Number Register Space
0x000 0x07F 0 D-PHY IP registers for Link 0
0x080 0x0FF D-PHY IP shared (mirrored)
0x100 0x17F External Shared (mirrored)
0x180 0x1FF External registers for Link 0
0x200 0x27F 1 D-PHY IP registers for Link 1
0x280 0x2FF D-PHY IP shared (mirrored)
0x300 0x37F External Shared (mirrored)
0x380 0x3FF External registers for Link 1
0x400 0x47F 2 D-PHY IP registers for Link 2
0x480 0x4FF D-PHY IP shared (mirrored)
0x500 0x57F External Shared (mirrored)
0x580 0x5FF External registers for Link 2
0x600 0x67F 3 D-PHY IP registers for Link 3
0x680 0x6FF D-PHY IP shared (mirrored)
0x700 0x77F External Shared (mirrored)
0x780 0x7FF External registers for Link 3
0x800 0x87F 4 D-PHY IP registers for Link 4
0x880 0x8FF D-PHY IP shared (mirrored)
0x900 0x97F External Shared (mirrored)
0x980 0x9FF External registers for Link 4
0xA00 0xA7F 5 D-PHY IP registers for Link 5
0xA80 0xAFF D-PHY IP shared (mirrored)
0xB00 0xB7F External Shared (mirrored)
0xB80 0xBFF External registers for Link 5
0xC00 0xC7F 6 D-PHY IP registers for Link 6
0xC80 0xCFF D-PHY IP shared (mirrored)
0xD00 0xD7F External Shared (mirrored)
0xD80 0xDFF External registers for Link 6

Each link has its own register space, with additional space reserved for connecting to an external agent. Those registers in the mirrored addresses are shared by all links. For an example of these mirrored registers, refer to the topic. For the D-PHY IP design example, the reserved space is used for TG registers as shown below:

Table 28.  D-PHY IP Register Map for Design Example
Start End Link Number Register Space
0x000 0x07F 0 D-PHY IP registers for Link 0
0x080 0x0FF D-PHY IP shared (mirrored)
0x100 0x17F TG top level registers mirrored across all links (mirrored)
0x180 0x1FF TG registers for Link 0
0x200 0x27F 1 D-PHY IP registers for Link 1
0x280 0x2FF D-PHY IP shared (mirrored)
0x300 0x37F TG top level registers mirrored across all links (mirrored)
0x380 0x3FF TG registers for Link 1
0x400 0x47F 2 D-PHY IP registers for Link 2
0x480 0x4FF D-PHY IP shared (mirrored)
0x500 0x57F TG top level registers mirrored across all links (mirrored)
0x580 0x5FF TG registers for Link 2
0x600 0x67F 3 D-PHY IP registers for Link 3
0x680 0x6FF D-PHY IP shared (mirrored)
0x700 0x77F TG top level registers mirrored across all links (mirrored)
0x780 0x7FF TG registers for Link 3
0x800 0x87F 4 D-PHY IP registers for Link 4
0x880 0x88F D-PHY IP shared (mirrored)
0x900 0x97F TG top level registers mirrored across all links (mirrored)
0x980 0x9FF TG registers for Link 4
0xA00 0xA7F 5 D-PHY IP registers for Link 5
0xA80 0xAFF D-PHY IP shared (mirrored)
0xB00 0xB7F TG top level registers mirrored across all links (mirrored)
0xB80 0xBFF TG registers for Link 5
0xC00 0xC7F 6 D-PHY IP registers for Link 6
0xC80 0xCFF D-PHY IP shared (mirrored)
0xD00 0xD7F TG top level registers mirrored across all links (mirrored)
0xD80 0xDFF TG registers for Link 6

The external register space is accessed using a simple register bus as shown below:

Figure 26. Core Register Bus Diagram

The AXI-Lite client on the D-PHY IP does sub-decode by looking at bit[8] of the AXI-Lite address. The register bus address bits are mapped as shown below:

Figure 27. AXI-Lite Bus Address to Register Bus Address

The waveform diagram below shows AXI-Lite write and read to external registers:

Figure 28. AXI-Lite Write to External Register Waveform
Figure 29. AXI-Lite Read from External Register Waveform