[PATCH 23/25] OMAP4: PM: Add CPUidle support
santosh.shilimkar at ti.com
Sun Sep 18 04:47:05 EDT 2011
On Friday 16 September 2011 11:15 PM, Kevin Hilman wrote:
> Hi Santosh,
> Santosh Shilimkar <santosh.shilimkar at ti.com> writes:
>> Add OMAP4 CPUIDLE support. CPU1 is left with defualt idle and
>> the low power state for it is managed via cpu-hotplug.
>> This patch adds MPUSS low power states in cpuidle.
>> C1 - CPU0 ON + CPU1 ON + MPU ON
>> C2 - CPU0 OFF + CPU1 OFF + MPU CSWR
>> C3 - CPU0 OFF + CPU1 OFF + MPU OSWR
>> OMAP4460 onwards, MPUSS power domain doesn't support OFF state any more
>> anymore just like CORE power domain. The deepest state supported is OSWr.
>> Ofcourse when MPUSS and CORE PD transitions to OSWR along with device
>> off mode, even the memory contemts are lost which is as good as
>> the PD off state.
>> On OMAP4 because of hardware constraints, no low power states are
>> targeted when both CPUs are online and in SMP mode. The low power
>> states are attempted only when secondary CPU gets offline to OFF
>> through hotplug infrastructure.
>> Thanks to Nicole Chalhoub <n-chalhoub at ti.com> for doing exhaustive
>> C-state latency profiling.
>> Signed-off-by: Rajendra Nayak <rnayak at ti.com>
>> Signed-off-by: Santosh Shilimkar <santosh.shilimkar at ti.com>
>> Cc: Kevin Hilman <khilman at ti.com>
> A handful of minor comments below...
Will take care of them.
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