On 22/04/16 10:57, Marc Zyngier wrote: > On 20/04/16 12:03, Jon Hunter wrote: >> Add a driver for the Tegra-AGIC interrupt controller which is compatible >> with the ARM GIC-400 interrupt controller. >> >> The Tegra AGIC (Audio GIC) is part of the Audio Processing Engine (APE) on >> Tegra210 and can route interrupts to either the GIC for the CPU subsystem >> or the Audio DSP (ADSP) within the APE. The AGIC uses CPU interface 0 to >> route interrupts to the CPU GIC and CPU interface 1 to route interrupts to >> the ADSP. >> >> The APE is located within its own power domain on the chip and so the >> AGIC needs to manage both the power domain and its clocks. Commit >> afbbd2338176 ("irqchip/gic: Document optional Clock and Power Domain >> properties") has already added clock and power-domain properties to the >> GIC binding and so we can make use of these for the AGIC. >> >> With the AGIC being located in a different power domain to the main CPU >> cluster this means that: >> 1. The interrupt controller cannot be registered via IRQCHIP_DECLARE() >> because it needs to be registered as a platform device so that the >> generic PM domain core will ensure that the power domain is available >> before probing. >> 2. The interrupt controller cannot be suspended/restored based upon >> changes in the CPU power state and needs to use runtime-pm instead. >> >> The GIC platform driver has been implemented by making the following >> changes to the core GIC driver: >> 1. Remove the dependency on CONFIG_CPU_PM from PM specific variables and >> functions so that they can be used by the platform driver even when >> CONFIG_CPU_PM is not selected. >> 2. Move the code that maps the GIC registers and parses the device-tree >> blob into a new function called gic_of_setup() that can be used by >> both the platform driver as well as the existing driver. >> 3. Add and register platform driver for the GIC. The platform driver >> uses the PM_CLK framework for managing the clocks used by the GIC >> and so select CONFIG_PM_CLK. >> >> Finally, a couple other notes on the implementation are: >> 1. Currently the GIC platform driver only supports non-root GICs and >> assumes that the GIC has a parent interrupt. It is assumed that >> root interrupt controllers need to be initialised early. >> 2. 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: Jon Hunter <jonathanh@xxxxxxxxxx> >> --- >> >> Please note that so far I have not added all the clock names for the >> various GIC versions (as described by the DT documentation). I thought >> we could add these as they are needed. > > So while the code looks OK, I'd like to stop adding more code to this > poor GIC driver, because it is starting to look like a huge mess. Agree. > What is preventing us to move this to a separate irq-gic-pm.c file? Absolutely nothing. Once we sort out the clocking, I will do that. Cheers Jon -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html