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linux/drivers/base
Rafael J. Wysocki cbc9ef0287 PM / Domains: Add preliminary support for cpuidle, v2
On some systems there are CPU cores located in the same power
domains as I/O devices.  Then, power can only be removed from the
domain if all I/O devices in it are not in use and the CPU core
is idle.  Add preliminary support for that to the generic PM domains
framework.

First, the platform is expected to provide a cpuidle driver with one
extra state designated for use with the generic PM domains code.
This state should be initially disabled and its exit_latency value
should be set to whatever time is needed to bring up the CPU core
itself after restoring power to it, not including the domain's
power on latency.  Its .enter() callback should point to a procedure
that will remove power from the domain containing the CPU core at
the end of the CPU power transition.

The remaining characteristics of the extra cpuidle state, referred to
as the "domain" cpuidle state below, (e.g. power usage, target
residency) should be populated in accordance with the properties of
the hardware.

Next, the platform should execute genpd_attach_cpuidle() on the PM
domain containing the CPU core.  That will cause the generic PM
domains framework to treat that domain in a special way such that:

 * When all devices in the domain have been suspended and it is about
   to be turned off, the states of the devices will be saved, but
   power will not be removed from the domain.  Instead, the "domain"
   cpuidle state will be enabled so that power can be removed from
   the domain when the CPU core is idle and the state has been chosen
   as the target by the cpuidle governor.

 * When the first I/O device in the domain is resumed and
   __pm_genpd_poweron(() is called for the first time after
   power has been removed from the domain, the "domain" cpuidle
   state will be disabled to avoid subsequent surprise power removals
   via cpuidle.

The effective exit_latency value of the "domain" cpuidle state
depends on the time needed to bring up the CPU core itself after
restoring power to it as well as on the power on latency of the
domain containing the CPU core.  Thus the "domain" cpuidle state's
exit_latency has to be recomputed every time the domain's power on
latency is updated, which may happen every time power is restored
to the domain, if the measured power on latency is greater than
the latency stored in the corresponding generic_pm_domain structure.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Reviewed-by: Kevin Hilman <khilman@ti.com>
2012-07-03 19:07:42 +02:00
..
power PM / Domains: Add preliminary support for cpuidle, v2 2012-07-03 19:07:42 +02:00
regmap regmap: Export regmap_reinit_cache() 2012-06-08 05:57:21 +08:00
attribute_container.c
base.h driver core: move the deferred probe pointer into the private area 2012-03-08 12:17:22 -08:00
bus.c Revert "driver core: check start node in klist_iter_init_node" 2012-04-19 19:17:30 -07:00
class.c Revert "driver core: check start node in klist_iter_init_node" 2012-04-19 19:17:30 -07:00
core.c driver-core: extend dev_printk() to pass structured data 2012-05-07 17:12:03 -07:00
cpu.c sched: Remove stale power aware scheduling remnants and dysfunctional knobs 2012-05-17 13:48:56 +02:00
dd.c driver core: fixup reversed deferred probe order 2012-06-13 13:42:39 -07:00
devres.c devres: Add devres_release() 2012-05-04 16:33:16 -07:00
devtmpfs.c devtmpfs: fix 'the the' typo 2012-04-18 15:37:35 -07:00
dma-buf.c dma-buf updates for 3.5 2012-05-25 09:37:26 -07:00
dma-coherent.c common: add dma_mmap_from_coherent() function 2012-05-21 15:06:09 +02:00
dma-contiguous.c drivers: add Contiguous Memory Allocator 2012-05-21 15:09:37 +02:00
dma-mapping.c drivers/base: Add export.h for EXPORT_SYMBOL/THIS_MODULE as required. 2011-10-31 19:31:38 -04:00
driver.c Driver Core: don't oops with unregistered driver in driver_find_device() 2012-05-14 08:46:01 -07:00
firmware_class.c firmware_class: Move request_firmware_nowait() to workqueues 2012-03-28 23:31:00 +02:00
firmware.c
hypervisor.c drivers/base: Add export.h for EXPORT_SYMBOL/THIS_MODULE as required. 2011-10-31 19:31:38 -04:00
init.c driver-core: implement 'sysdev' functionality for regular devices and buses 2011-12-14 14:29:38 -08:00
isa.c
Kconfig drivers: add Contiguous Memory Allocator 2012-05-21 15:09:37 +02:00
Makefile drivers: add Contiguous Memory Allocator 2012-05-21 15:09:37 +02:00
map.c
memory.c Linux 3.3-rc7 2012-03-14 07:44:11 +01:00
module.c
node.c mm: fix off-by-one bug in print_nodes_state() 2012-05-29 16:22:19 -07:00
platform.c drivercore: Output common devicetree information in uevent 2012-02-01 14:26:30 -07:00
soc.c mode_t whack-a-mole: ->is_visible() returns umode_t... 2012-05-29 23:28:42 -04:00
syscore.c PM: Reintroduce dropped call to check_wakeup_irqs 2011-07-11 10:51:49 +02:00
topology.c cpu: convert 'cpu' and 'machinecheck' sysdev_class to a regular subsystem 2011-12-21 14:29:42 -08:00
transport_class.c drivers/base: transport_class explicitly requires EXPORT_SYMBOL 2011-10-31 19:31:15 -04:00