| Message ID | 20130814115623.5193.36974.stgit@preeti.in.ibm.com (mailing list archive) |
|---|---|
| State | RFC, archived |
| Headers | show |
On Wed, 2013-08-14 at 17:26 +0530, Preeti U Murthy wrote: > This patch hooks into the existing broadcast framework along with the support > that this patchset introduces for ppc, and the cpuidle driver backend > for powernv(posted out by Deepthi Dharwar:https://lkml.org/lkml/2013/7/23/128) > to add sleep state as one of the deep idle states, in which the decrementer > is switched off. > > However in this patch, we only emulate sleep by going into a state which does > a nap with the decrementer interrupts disabled, termed as longnap. This enables > focus on the timer broadcast framework for ppc in this series of patches , > which is required as a first step to enable sleep on ppc. This is only for debug / proof of concept right ? We should use a real sleep here. If we need to know whether the FW supports it (PORE etc...) we shall add a device-tree property from the FW to indicate that fact. Cheers, Ben. > Signed-off-by: Preeti U Murthy <preeti@linux.vnet.ibm.com> > --- > > arch/powerpc/platforms/powernv/processor_idle.c | 48 +++++++++++++++++++++++ > 1 file changed, 47 insertions(+), 1 deletion(-) > > diff --git a/arch/powerpc/platforms/powernv/processor_idle.c b/arch/powerpc/platforms/powernv/processor_idle.c > index f43ad91a..9aca502 100644 > --- a/arch/powerpc/platforms/powernv/processor_idle.c > +++ b/arch/powerpc/platforms/powernv/processor_idle.c > @@ -9,16 +9,18 @@ > #include <linux/cpuidle.h> > #include <linux/cpu.h> > #include <linux/notifier.h> > +#include <linux/clockchips.h> > > #include <asm/machdep.h> > #include <asm/runlatch.h> > +#include <asm/time.h> > > struct cpuidle_driver powernv_idle_driver = { > .name = "powernv_idle", > .owner = THIS_MODULE, > }; > > -#define MAX_IDLE_STATE_COUNT 2 > +#define MAX_IDLE_STATE_COUNT 3 > > static int max_idle_state = MAX_IDLE_STATE_COUNT - 1; > static struct cpuidle_device __percpu *powernv_cpuidle_devices; > @@ -54,6 +56,43 @@ static int nap_loop(struct cpuidle_device *dev, > return index; > } > > +/* Emulate sleep, with long nap. > + * During sleep, the core does not receive decrementer interrupts. > + * Emulate sleep using long nap with decrementers interrupts disabled. > + * This is an initial prototype to test the timer offload framework for ppc. > + * We will eventually introduce the sleep state once the timer offload framework > + * for ppc is stable. > + */ > +static int longnap_loop(struct cpuidle_device *dev, > + struct cpuidle_driver *drv, > + int index) > +{ > + int cpu = dev->cpu; > + > + unsigned long lpcr = mfspr(SPRN_LPCR); > + > + lpcr &= ~(LPCR_MER | LPCR_PECE); /* lpcr[mer] must be 0 */ > + > + /* exit powersave upon external interrupt, but not decrementer > + * interrupt, Emulate sleep. > + */ > + lpcr |= LPCR_PECE0; > + > + if (cpu != bc_cpu) { > + mtspr(SPRN_LPCR, lpcr); > + clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &cpu); > + power7_nap(); > + clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &cpu); > + } else { > + /* Wakeup on a decrementer interrupt, Do a nap */ > + lpcr |= LPCR_PECE1; > + mtspr(SPRN_LPCR, lpcr); > + power7_nap(); > + } > + > + return index; > +} > + > /* > * States for dedicated partition case. > */ > @@ -72,6 +111,13 @@ static struct cpuidle_state powernv_states[MAX_IDLE_STATE_COUNT] = { > .exit_latency = 10, > .target_residency = 100, > .enter = &nap_loop }, > + { /* LongNap */ > + .name = "LongNap", > + .desc = "LongNap", > + .flags = CPUIDLE_FLAG_TIME_VALID, > + .exit_latency = 10, > + .target_residency = 100, > + .enter = &longnap_loop }, > }; > > static int powernv_cpuidle_add_cpu_notifier(struct notifier_block *n, -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi Ben, On 08/22/2013 08:58 AM, Benjamin Herrenschmidt wrote: > On Wed, 2013-08-14 at 17:26 +0530, Preeti U Murthy wrote: >> This patch hooks into the existing broadcast framework along with the support >> that this patchset introduces for ppc, and the cpuidle driver backend >> for powernv(posted out by Deepthi Dharwar:https://lkml.org/lkml/2013/7/23/128) >> to add sleep state as one of the deep idle states, in which the decrementer >> is switched off. >> >> However in this patch, we only emulate sleep by going into a state which does >> a nap with the decrementer interrupts disabled, termed as longnap. This enables >> focus on the timer broadcast framework for ppc in this series of patches , >> which is required as a first step to enable sleep on ppc. > > This is only for debug / proof of concept right ? We should use a real > sleep here. > > If we need to know whether the FW supports it (PORE etc...) we shall add > a device-tree property from the FW to indicate that fact. We also need the sleep support right? The context management, I mean. Yes it is a debug patch, so as to first ensure that we have the hook up to the broadcast framework done right. Regards Preeti U Murthy -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/powerpc/platforms/powernv/processor_idle.c b/arch/powerpc/platforms/powernv/processor_idle.c index f43ad91a..9aca502 100644 --- a/arch/powerpc/platforms/powernv/processor_idle.c +++ b/arch/powerpc/platforms/powernv/processor_idle.c @@ -9,16 +9,18 @@ #include <linux/cpuidle.h> #include <linux/cpu.h> #include <linux/notifier.h> +#include <linux/clockchips.h> #include <asm/machdep.h> #include <asm/runlatch.h> +#include <asm/time.h> struct cpuidle_driver powernv_idle_driver = { .name = "powernv_idle", .owner = THIS_MODULE, }; -#define MAX_IDLE_STATE_COUNT 2 +#define MAX_IDLE_STATE_COUNT 3 static int max_idle_state = MAX_IDLE_STATE_COUNT - 1; static struct cpuidle_device __percpu *powernv_cpuidle_devices; @@ -54,6 +56,43 @@ static int nap_loop(struct cpuidle_device *dev, return index; } +/* Emulate sleep, with long nap. + * During sleep, the core does not receive decrementer interrupts. + * Emulate sleep using long nap with decrementers interrupts disabled. + * This is an initial prototype to test the timer offload framework for ppc. + * We will eventually introduce the sleep state once the timer offload framework + * for ppc is stable. + */ +static int longnap_loop(struct cpuidle_device *dev, + struct cpuidle_driver *drv, + int index) +{ + int cpu = dev->cpu; + + unsigned long lpcr = mfspr(SPRN_LPCR); + + lpcr &= ~(LPCR_MER | LPCR_PECE); /* lpcr[mer] must be 0 */ + + /* exit powersave upon external interrupt, but not decrementer + * interrupt, Emulate sleep. + */ + lpcr |= LPCR_PECE0; + + if (cpu != bc_cpu) { + mtspr(SPRN_LPCR, lpcr); + clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &cpu); + power7_nap(); + clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &cpu); + } else { + /* Wakeup on a decrementer interrupt, Do a nap */ + lpcr |= LPCR_PECE1; + mtspr(SPRN_LPCR, lpcr); + power7_nap(); + } + + return index; +} + /* * States for dedicated partition case. */ @@ -72,6 +111,13 @@ static struct cpuidle_state powernv_states[MAX_IDLE_STATE_COUNT] = { .exit_latency = 10, .target_residency = 100, .enter = &nap_loop }, + { /* LongNap */ + .name = "LongNap", + .desc = "LongNap", + .flags = CPUIDLE_FLAG_TIME_VALID, + .exit_latency = 10, + .target_residency = 100, + .enter = &longnap_loop }, }; static int powernv_cpuidle_add_cpu_notifier(struct notifier_block *n,
This patch hooks into the existing broadcast framework along with the support that this patchset introduces for ppc, and the cpuidle driver backend for powernv(posted out by Deepthi Dharwar:https://lkml.org/lkml/2013/7/23/128) to add sleep state as one of the deep idle states, in which the decrementer is switched off. However in this patch, we only emulate sleep by going into a state which does a nap with the decrementer interrupts disabled, termed as longnap. This enables focus on the timer broadcast framework for ppc in this series of patches , which is required as a first step to enable sleep on ppc. Signed-off-by: Preeti U Murthy <preeti@linux.vnet.ibm.com> --- arch/powerpc/platforms/powernv/processor_idle.c | 48 +++++++++++++++++++++++ 1 file changed, 47 insertions(+), 1 deletion(-) -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html