On most common ARM systems, the low-power states a CPU can be put into are
not discoverable in HW and require device tree bindings to describe
power down suspend operations and idle states parameters.

In order to enable DT based idle states and configure idle drivers, this
patch implements the bulk infrastructure required to parse the device tree
idle states bindings and initialize the corresponding CPUidle driver states
data.

Code that initializes idle states checks the CPU idle driver cpumask so
that multiple CPU idle drivers can be initialized through it in the
kernel. The CPU idle driver cpumask defines which idle states should be
considered valid for the driver, ie idle states that are valid on a set
of cpus the idle driver manages.

Signed-off-by: Lorenzo Pieralisi <redacted>
---
 drivers/cpuidle/Kconfig          |   9 ++
 drivers/cpuidle/Makefile         |   1 +
 drivers/cpuidle/of_idle_states.c | 282 +++++++++++++++++++++++++++++++++++++++
 drivers/cpuidle/of_idle_states.h |   8 ++
 4 files changed, 300 insertions(+)
 create mode 100644 drivers/cpuidle/of_idle_states.c
 create mode 100644 drivers/cpuidle/of_idle_states.h

diff --git a/drivers/cpuidle/Kconfig b/drivers/cpuidle/Kconfig
index 1b96fb9..760ce20 100644
--- a/drivers/cpuidle/Kconfig
+++ b/drivers/cpuidle/Kconfig

@@ -30,6 +30,15 @@ config CPU_IDLE_GOV_MENU
        bool "Menu governor (for tickless system)"
        default y

+config OF_IDLE_STATES