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Qualcomm SoCs based on the RPM architecture have a MSM Power Manager (MPM) in always-on domain. In addition to managing resources during sleep, the hardware also has an interrupt controller that monitors the interrupts when the system is asleep, wakes up the APSS when one of these interrupts occur and replays it to GIC after it becomes operational. It adds an irqchip driver for this interrupt controller, and here are some notes about it. - For given SoC, a fixed number of MPM pins are supported, e.g. 96 pins on QCM2290. Each of these MPM pins can be either a MPM_GIC pin or a MPM_GPIO pin. The mapping between MPM_GIC pin and GIC interrupt is defined by SoC, as well as the mapping between MPM_GPIO pin and GPIO number. The former mapping is retrieved from device tree, while the latter is defined in TLMM pinctrl driver. - The power domain (PD) .power_off hook is used to notify RPM that APSS is about to power collapse. This requires MPM PD be the parent PD of CPU cluster. - When SoC gets awake from sleep mode, the driver will receive an interrupt from RPM, so that it can replay interrupt for particular polarity. Signed-off-by: Shawn Guo <shawn.guo@linaro.org> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220308080534.3384532-3-shawn.guo@linaro.org
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.