• Lorenzo Pieralisi's avatar
    ACPI/IORT: Introduce linker section for IORT entries probing · 34ceea27
    Lorenzo Pieralisi authored
    Since commit e647b532 ("ACPI: Add early device probing
    infrastructure") the kernel has gained the infrastructure that allows
    adding linker script section entries to execute ACPI driver callbacks
    (ie probe routines) for all subsystems that register a table entry
    in the respective kernel section (eg clocksource, irqchip).
    
    Since ARM IOMMU devices data is described through IORT tables when
    booting with ACPI, the ARM IOMMU drivers must be made able to hook ACPI
    callback routines that are called to probe IORT entries and initialize
    the respective IOMMU devices.
    
    To avoid adding driver specific hooks into IORT table initialization
    code (breaking therefore code modularity - ie ACPI IORT code must be made
    aware of ARM SMMU drivers ACPI init callbacks), this patch adds code
    that allows ARM SMMU drivers to take advantage of the ACPI early probing
    infrastructure, so that they can add linker script section entries
    containing drivers callback to be executed on IORT tables detection.
    
    Since IORT nodes are differentiated by a type, the callback routines
    can easily parse the IORT table entries, check the IORT nodes and
    carry out some actions whenever the IORT node type associated with
    the driver specific callback is matched.
    Signed-off-by: default avatarLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
    Reviewed-by: default avatarHanjun Guo <hanjun.guo@linaro.org>
    Reviewed-by: default avatarTomasz Nowicki <tn@semihalf.com>
    Tested-by: default avatarHanjun Guo <hanjun.guo@linaro.org>
    Tested-by: default avatarTomasz Nowicki <tn@semihalf.com>
    Cc: Tomasz Nowicki <tn@semihalf.com>
    Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
    Cc: Marc Zyngier <marc.zyngier@arm.com>
    Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
    34ceea27
iort.c 9.32 KB