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| author | Shreyas B. Prabhu <shreyas@linux.vnet.ibm.com> | 2014-12-10 00:26:51 +0530 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2014-12-15 10:46:40 +1100 |
| commit | 8eb8ac89a364305d05ad16be983b7890eb462cc3 (patch) | |
| tree | 4661793e77c8b83bc5c805f3502a8fb5a037aa32 /arch/powerpc/platforms/powernv/smp.c | |
| parent | 8117ac6a6c2fa0f847ff6a21a1f32c8d2c8501d0 (diff) | |
| download | linux-8eb8ac89a364305d05ad16be983b7890eb462cc3.tar.gz linux-8eb8ac89a364305d05ad16be983b7890eb462cc3.tar.xz | |
powerpc/powernv: Enable Offline CPUs to enter deep idle states
The secondary threads should enter deep idle states so as to gain maximum
powersavings when the entire core is offline. To do so the offline path
must be made aware of the available deepest idle state. Hence probe the
device tree for the possible idle states in powernv core code and
expose the deepest idle state through flags.
Since the device tree is probed by the cpuidle driver as well, move
the parameters required to discover the idle states into an appropriate
common place to both the driver and the powernv core code.
Another point is that fastsleep idle state may require workarounds in
the kernel to function properly. This workaround is introduced in the
subsequent patches. However neither the cpuidle driver or the hotplug
path need be bothered about this workaround.
They will be taken care of by the core powernv code.
Originally-by: Srivatsa S. Bhat <srivatsa@mit.edu>
Signed-off-by: Preeti U. Murthy <preeti@linux.vnet.ibm.com>
Signed-off-by: Shreyas B. Prabhu <shreyas@linux.vnet.ibm.com>
Reviewed-by: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: linux-pm@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/platforms/powernv/smp.c')
| -rw-r--r-- | arch/powerpc/platforms/powernv/smp.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/arch/powerpc/platforms/powernv/smp.c b/arch/powerpc/platforms/powernv/smp.c index b716f666e48a..83299ef2dc3d 100644 --- a/arch/powerpc/platforms/powernv/smp.c +++ b/arch/powerpc/platforms/powernv/smp.c @@ -150,6 +150,7 @@ static void pnv_smp_cpu_kill_self(void) { unsigned int cpu; unsigned long srr1; + u32 idle_states; /* Standard hot unplug procedure */ local_irq_disable(); @@ -160,13 +161,17 @@ static void pnv_smp_cpu_kill_self(void) generic_set_cpu_dead(cpu); smp_wmb(); + idle_states = pnv_get_supported_cpuidle_states(); /* We don't want to take decrementer interrupts while we are offline, * so clear LPCR:PECE1. We keep PECE2 enabled. */ mtspr(SPRN_LPCR, mfspr(SPRN_LPCR) & ~(u64)LPCR_PECE1); while (!generic_check_cpu_restart(cpu)) { ppc64_runlatch_off(); - srr1 = power7_nap(1); + if (idle_states & OPAL_PM_SLEEP_ENABLED) + srr1 = power7_sleep(); + else + srr1 = power7_nap(1); ppc64_runlatch_on(); /* |