profile/signal-missing

Remedy ¶

Add the missing signal to the design, or drop the interface requirement if this board genuinely does not implement it.

What it means ¶

An interface profile lists the signals that a bus must have. This fires when the interface is in use, meaning its anchor signal (e.g. SPI-NOR’s chip-select) and at least one other signal are present, but a required signal net is absent. Signals are matched by net name, usually by suffix, though a profile may also match by prefix, glob or regex. On a design that declares a host, host-incomplete reports instead and this rule stands down.

The shipped eMMC profile has an instance key, and a profile with that key asks this of each bus on its own. A bus is the nets named from one anchor net’s stem, so SD2_CMD’s bus is SD2_CLK, SD2_DATA0 and so on, and a signal on another bus does not count. A bus that carries one of the profile’s excludes lines is a different interface, and the rule does not check it. A removable SD card’s slot has a card detect line, so the eMMC check leaves the slot out.

Why engineers want it ¶

The most common bus-wiring slip is a forgotten line, with five of six SPI-NOR signals wired and one missed. Each “verify signal X connected” review item is really this one check applied per signal. The profile encodes the required set once, and the rule flags whichever member is missing.

Why it anchors on a present signal (and what it does not catch) ¶

A datalog rule fires on rows; an absent net is not a row. So “IO2 is missing” is reported against the interface’s anchor net (which is present), one finding per missing signal. When the anchor itself is absent, on a wholly-missing interface, there is nothing to anchor on and the rule is silent, by design. To detect a required interface that is entirely absent, you need a declared host or a design-intent modules declaration (intent/module-missing), not a name convention.

For software readers ¶

The profile is an interface/protocol definition, and this rule checks that an implementation provides every member that the interface declares. “Anchored on a present signal” is like validating a partially-filled config, where you can flag the missing keys only once you can tell the config is meant to be there at all.