39 lines
1.7 KiB
Plaintext
39 lines
1.7 KiB
Plaintext
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DT compatible string versioning for SiFive open-source IP blocks
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This document describes the version specification for DT "compatible"
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strings for open-source SiFive IP blocks. HDL for these IP blocks
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can be found in this public repository:
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https://github.com/sifive/sifive-blocks
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IP block-specific DT compatible strings are contained within the HDL,
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in the form "sifive,<ip-block-name><integer version number>".
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An example is "sifive,uart0" from:
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https://github.com/sifive/sifive-blocks/blob/v1.0/src/main/scala/devices/uart/UART.scala#L43
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Until these IP blocks (or IP integration) support version
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auto-discovery, the maintainers of these IP blocks intend to increment
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the suffixed number in the compatible string whenever the software
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interface to these IP blocks changes, or when the functionality of the
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underlying IP blocks changes in a way that software should be aware of.
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Driver developers can use compatible string "match" values such as
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"sifive,uart0" to indicate that their driver is compatible with the
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register interface and functionality associated with the relevant
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upstream sifive-blocks commits. It is expected that most drivers will
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match on these IP block-specific compatible strings.
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DT data authors, when writing data for a particular SoC, should
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continue to specify an SoC-specific compatible string value, such as
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"sifive,fu540-c000-uart". This way, if SoC-specific
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integration-specific bug fixes or workarounds are needed, the kernel
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or other system software can match on this string to apply them. The
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IP block-specific compatible string (such as "sifive,uart0") should
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then be specified as a subsequent value.
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An example of this style:
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compatible = "sifive,fu540-c000-uart", "sifive,uart0";
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