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authorShreyas B. Prabhu <shreyas@linux.vnet.ibm.com>2014-12-09 21:56:51 +0300
committerMichael Ellerman <mpe@ellerman.id.au>2014-12-15 02:46:40 +0300
commit8eb8ac89a364305d05ad16be983b7890eb462cc3 (patch)
tree4661793e77c8b83bc5c805f3502a8fb5a037aa32 /arch/powerpc/platforms
parent8117ac6a6c2fa0f847ff6a21a1f32c8d2c8501d0 (diff)
downloadlinux-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')
-rw-r--r--arch/powerpc/platforms/powernv/powernv.h2
-rw-r--r--arch/powerpc/platforms/powernv/setup.c49
-rw-r--r--arch/powerpc/platforms/powernv/smp.c7
3 files changed, 57 insertions, 1 deletions
diff --git a/arch/powerpc/platforms/powernv/powernv.h b/arch/powerpc/platforms/powernv/powernv.h
index 6c8e2d188cd0..604c48e7879a 100644
--- a/arch/powerpc/platforms/powernv/powernv.h
+++ b/arch/powerpc/platforms/powernv/powernv.h
@@ -29,6 +29,8 @@ static inline u64 pnv_pci_dma_get_required_mask(struct pci_dev *pdev)
}
#endif
+extern u32 pnv_get_supported_cpuidle_states(void);
+
extern void pnv_lpc_init(void);
bool cpu_core_split_required(void);
diff --git a/arch/powerpc/platforms/powernv/setup.c b/arch/powerpc/platforms/powernv/setup.c
index 30b1c3e298a6..88e579e62a73 100644
--- a/arch/powerpc/platforms/powernv/setup.c
+++ b/arch/powerpc/platforms/powernv/setup.c
@@ -288,6 +288,55 @@ static void __init pnv_setup_machdep_rtas(void)
}
#endif /* CONFIG_PPC_POWERNV_RTAS */
+static u32 supported_cpuidle_states;
+
+u32 pnv_get_supported_cpuidle_states(void)
+{
+ return supported_cpuidle_states;
+}
+
+static int __init pnv_init_idle_states(void)
+{
+ struct device_node *power_mgt;
+ int dt_idle_states;
+ const __be32 *idle_state_flags;
+ u32 len_flags, flags;
+ int i;
+
+ supported_cpuidle_states = 0;
+
+ if (cpuidle_disable != IDLE_NO_OVERRIDE)
+ return 0;
+
+ if (!firmware_has_feature(FW_FEATURE_OPALv3))
+ return 0;
+
+ power_mgt = of_find_node_by_path("/ibm,opal/power-mgt");
+ if (!power_mgt) {
+ pr_warn("opal: PowerMgmt Node not found\n");
+ return 0;
+ }
+
+ idle_state_flags = of_get_property(power_mgt,
+ "ibm,cpu-idle-state-flags", &len_flags);
+ if (!idle_state_flags) {
+ pr_warn("DT-PowerMgmt: missing ibm,cpu-idle-state-flags\n");
+ return 0;
+ }
+
+ dt_idle_states = len_flags / sizeof(u32);
+
+ for (i = 0; i < dt_idle_states; i++) {
+ flags = be32_to_cpu(idle_state_flags[i]);
+ supported_cpuidle_states |= flags;
+ }
+
+ return 0;
+}
+
+subsys_initcall(pnv_init_idle_states);
+
+
static int __init pnv_probe(void)
{
unsigned long root = of_get_flat_dt_root();
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();
/*