Idle states on most ARM platforms can be characterized by a set of parameters that are platform agnostic and describe the HW idle states features. So far, CPU idle drivers for ARM platforms required the definition of parameters through static tables, duplicating control data for different platforms. Moreover, the lack of standardization on firmware interfaces hampered any standardization effort, resulting in CPU idle drivers for ARM platforms containing duplicated code and platform specific power down routines. The introduction of the PSCI firmware interface, and more in general, well defined suspend back-ends, allows the definition of generic idle states and the respective kernel infrastructure to support them. Building on top of DT idle states bindings[1], that standardize idle states parameters and corresponding suspend back-ends, this patchset provides code that parses DT idle states nodes and builds at run-time the control data infrastructure required by the generic ARM64 CPU idle driver, that just becomes a container for idle states storage. Idle states define an entry method (eg PSCI), that requires the respective kernel back-end to be invoked to initialize idle states parameters, so that when the idle driver executes the back-end specific entry method a table look-up can be carried out to retrieve the corresponding idle state parameter. The idle states bindings can be extended with new back-ends; the idle states parser must be updated accordingly so that the corresponding back end initializer can be invoked at boot time for parameters initialization. Patchset has been tested on AEM v8 models, on top of the bootwrapper PSCI CPU SUSPEND implementation which provides simulated core power gating. [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2014-February/233478.html Lorenzo Pieralisi (4): arm64: kernel: implement DT based idle states infrastructure arm64: add PSCI CPU_SUSPEND based cpu_suspend support drivers: cpuidle: CPU idle ARM64 driver arm64: boot: dts: update rtsm aemv8 dts with PSCI and idle states arch/arm64/Kconfig | 4 + arch/arm64/boot/dts/rtsm_ve-aemv8a.dts | 50 ++++- arch/arm64/include/asm/idle_states.h | 20 ++ arch/arm64/include/asm/psci.h | 6 + arch/arm64/kernel/Makefile | 1 + arch/arm64/kernel/idle_states.c | 398 +++++++++++++++++++++++++++++++++ arch/arm64/kernel/psci.c | 84 +++++++ drivers/cpuidle/Kconfig | 5 + drivers/cpuidle/Kconfig.arm64 | 13 ++ drivers/cpuidle/Makefile | 4 + drivers/cpuidle/cpuidle-arm64.c | 41 ++++ 11 files changed, 618 insertions(+), 8 deletions(-) create mode 100644 arch/arm64/include/asm/idle_states.h create mode 100644 arch/arm64/kernel/idle_states.c create mode 100644 drivers/cpuidle/Kconfig.arm64 create mode 100644 drivers/cpuidle/cpuidle-arm64.c -- 1.8.4 -- 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
