1DT compatible string versioning for SiFive open-source IP blocks 2 3This document describes the version specification for DT "compatible" 4strings for open-source SiFive IP blocks. HDL for these IP blocks 5can be found in this public repository: 6 7https://github.com/sifive/sifive-blocks 8 9IP block-specific DT compatible strings are contained within the HDL, 10in the form "sifive,<ip-block-name><integer version number>". 11 12An example is "sifive,uart0" from: 13 14https://github.com/sifive/sifive-blocks/blob/v1.0/src/main/scala/devices/uart/UART.scala#L43 15 16Until these IP blocks (or IP integration) support version 17auto-discovery, the maintainers of these IP blocks intend to increment 18the suffixed number in the compatible string whenever the software 19interface to these IP blocks changes, or when the functionality of the 20underlying IP blocks changes in a way that software should be aware of. 21 22Driver developers can use compatible string "match" values such as 23"sifive,uart0" to indicate that their driver is compatible with the 24register interface and functionality associated with the relevant 25upstream sifive-blocks commits. It is expected that most drivers will 26match on these IP block-specific compatible strings. 27 28DT data authors, when writing data for a particular SoC, should 29continue to specify an SoC-specific compatible string value, such as 30"sifive,fu540-c000-uart". This way, if SoC-specific 31integration-specific bug fixes or workarounds are needed, the kernel 32or other system software can match on this string to apply them. The 33IP block-specific compatible string (such as "sifive,uart0") should 34then be specified as a subsequent value. 35 36An example of this style: 37 38 compatible = "sifive,fu540-c000-uart", "sifive,uart0"; 39