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| author | Joseph Lo <josephl@nvidia.com> | 2013-01-16 17:33:55 +0000 |
|---|---|---|
| committer | Stephen Warren <swarren@nvidia.com> | 2013-01-28 11:20:38 -0700 |
| commit | 1d328606c66b9bb1c0552f585943d596f37ae3b9 (patch) | |
| tree | ebb8a6e60de7b5b96100ffbcda57445116a906ef /arch/arm/mach-tegra/Kconfig | |
| parent | afec581c4b53e03a97d9ef1b7a746a67967573cf (diff) | |
| download | blackbird-op-linux-1d328606c66b9bb1c0552f585943d596f37ae3b9.tar.gz blackbird-op-linux-1d328606c66b9bb1c0552f585943d596f37ae3b9.zip | |
ARM: tegra20: cpuidle: apply coupled cpuidle for powered-down mode
The "powered-down" cpuidle mode of Tegra20 needs the CPU0 be the last one
core to go into this mode before other core. The coupled cpuidle framework
can help to sync the MPCore to coupled state then go into "powered-down"
idle mode together. The driver can just assume the MPCore come into
"powered-down" mode at the same time. No need to take care if the CPU_0
goes into this mode along and only can put it into safe idle mode (WFI).
The powered-down state of Tegra20 requires power gating both CPU cores.
When the secondary CPU requests to enter powered-down state, it saves
its own contexts and then enters WFI for waiting CPU0 in the same state.
When the CPU0 requests powered-down state, it attempts to put the secondary
CPU into reset to prevent it from waking up. Then power down both CPUs
together and power off the cpu rail.
Be aware of that, you may see the legacy power state "LP2" in the code
which is exactly the same meaning of "CPU power down".
Based on the work by:
Colin Cross <ccross@android.com>
Gary King <gking@nvidia.com>
Signed-off-by: Joseph Lo <josephl@nvidia.com>
Acked-by: Colin Cross <ccross@android.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Diffstat (limited to 'arch/arm/mach-tegra/Kconfig')
| -rw-r--r-- | arch/arm/mach-tegra/Kconfig | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/arm/mach-tegra/Kconfig b/arch/arm/mach-tegra/Kconfig index 1ec7f80e2af5..abc688fd4807 100644 --- a/arch/arm/mach-tegra/Kconfig +++ b/arch/arm/mach-tegra/Kconfig @@ -4,6 +4,7 @@ comment "NVIDIA Tegra options" config ARCH_TEGRA_2x_SOC bool "Enable support for Tegra20 family" + select ARCH_NEEDS_CPU_IDLE_COUPLED if SMP select ARCH_REQUIRE_GPIOLIB select ARM_ERRATA_720789 select ARM_ERRATA_742230 if SMP |
