• Mark Rutland's avatar
    Docs: dt: add generic MSI bindings · 126b16e2
    Mark Rutland authored
    Currently msi-parent is used in a couple of drivers despite being fairly
    underspecified. This patch adds a generic binding for MSIs (including
    the existing msi-parent property) enabling the description of platform
    devices capable of using MSIs.
    While MSIs are primarily distinguished by doorbell and payload, some MSI
    controllers (e.g. the GICv3 ITS) also use side-band information
    accompanying the write to identify the master which originated the MSI,
    to allow for sandboxing. This sideband information is non-probeable and
    needs to be described in the DT. Other MSI controllers may have
    additional configuration details which need to be described per-master.
    This patch adds a generic msi-parent binding document, extending the
    de-facto standard with a new (optional) #msi-cells which can be used to
    express any per-master configuration and/or sideband data. This is
    sufficient to describe non-hotpluggable devices.
    For busses where sideband data may be derived from some bus-specific
    master ID scheme, other properties will be required to describe the
    Signed-off-by: default avatarMark Rutland <mark.rutland@arm.com>
    Acked-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
    Signed-off-by: default avatarRob Herring <robh@kernel.org>
msi.txt 3.76 KB