• Jon Hunter's avatar
    irqchip/gic: Add platform driver for non-root GICs that require RPM · 9c8edddf
    Jon Hunter authored
    Add a platform driver to support non-root GICs that require runtime
    power-management. Currently, only non-root GICs are supported because
    the functions, smp_cross_call() and set_handle_irq(), that need to
    be called for a root controller are located in the __init section and
    so cannot be called by the platform driver.
    
    The GIC platform driver re-uses many functions from the existing GIC
    driver including some functions to save and restore the GIC context
    during power transitions. The functions for saving and restoring the
    GIC context are currently only defined if CONFIG_CPU_PM is enabled and
    to ensure that these functions are always defined when the platform
    driver is enabled, a dependency on CONFIG_ARM_GIC_PM (which selects the
    platform driver) has been added.
    
    In order to re-use the private GIC initialisation code, a new public
    function, gic_of_init_child(), has been added which calls various
    private functions to initialise the GIC. This is different from the
    existing gic_of_init() because it only supports non-root GICs (ie. does
    not call smp_cross_call() is set_handle_irq()) and is not located in
    the __init section (so can be used by platform drivers). Furthermore,
    gic_of_init_child() dynamically allocates memory for the GIC chip data
    which is also different from gic_of_init().
    
    There is no specific suspend handling for GICs registered as platform
    devices. Non-wakeup interrupts will be disabled by the kernel during
    late suspend, however, this alone will not power down the GIC if
    interrupts have been requested and not freed. Therefore, requestors of
    non-wakeup interrupts will need to free them on entering suspend in
    order to power-down the GIC.
    Signed-off-by: default avatarJon Hunter <jonathanh@nvidia.com>
    Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
    9c8edddf