| Message ID | 1412149560-2953-2-git-send-email-shreyas@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Benjamin Herrenschmidt |
| Headers | show |
On Wed, 2014-10-01 at 13:15 +0530, Shreyas B. Prabhu wrote: > From: "Srivatsa S. Bhat" <srivatsa@mit.edu> > > The offline cpus Arguably "cpus" here should be "secondary threads" to make the commit message a bit more comprehensible. A few more nits below... > 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. > > 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: Srivatsa S. Bhat <srivatsa@mit.edu> > Signed-off-by: Shreyas B. Prabhu <shreyas@linux.vnet.ibm.com> > [ Changelog modified by preeti@linux.vnet.ibm.com ] > Signed-off-by: Preeti U. Murthy <preeti@linux.vnet.ibm.com> > --- > arch/powerpc/include/asm/opal.h | 4 +++ > arch/powerpc/platforms/powernv/powernv.h | 7 +++++ > arch/powerpc/platforms/powernv/setup.c | 51 ++++++++++++++++++++++++++++++++ > arch/powerpc/platforms/powernv/smp.c | 11 ++++++- > drivers/cpuidle/cpuidle-powernv.c | 7 ++--- > 5 files changed, 75 insertions(+), 5 deletions(-) > > diff --git a/arch/powerpc/include/asm/opal.h b/arch/powerpc/include/asm/opal.h > index 86055e5..28b8342 100644 > --- a/arch/powerpc/include/asm/opal.h > +++ b/arch/powerpc/include/asm/opal.h > @@ -772,6 +772,10 @@ extern struct kobject *opal_kobj; > /* /ibm,opal */ > extern struct device_node *opal_node; > > +/* Flags used for idle state discovery from the device tree */ > +#define IDLE_INST_NAP 0x00010000 /* nap instruction can be used */ > +#define IDLE_INST_SLEEP 0x00020000 /* sleep instruction can be used */ Please provide a better explanation if what this is about, maybe a commend describing the device-tree property. Also those macros have names too likely to collide or be confused with other uses. Use something a bit less ambiguous such as OPAL_PM_NAP_AVAILABLE, OPAL_PM_SLEEP_ENABLED,... Also put that in the part of opal.h that isn't the linux internal implementation, but instead the "API" part. This will help when we finally split the file. > /* API functions */ > int64_t opal_invalid_call(void); > int64_t opal_console_write(int64_t term_number, __be64 *length, > diff --git a/arch/powerpc/platforms/powernv/powernv.h b/arch/powerpc/platforms/powernv/powernv.h > index 75501bf..31ece13 100644 > --- a/arch/powerpc/platforms/powernv/powernv.h > +++ b/arch/powerpc/platforms/powernv/powernv.h > @@ -23,6 +23,13 @@ static inline int pnv_pci_dma_set_mask(struct pci_dev *pdev, u64 dma_mask) > } > #endif > > +/* Flags to indicate which of the CPU idle states are available for use */ > + > +#define IDLE_USE_NAP (1UL << 0) > +#define IDLE_USE_SLEEP (1UL << 1) This somewhat duplicates the opal.h definitions, can't we just re-use them ? > +extern unsigned int 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 5a0e2dc..2dca1d8 100644 > --- a/arch/powerpc/platforms/powernv/setup.c > +++ b/arch/powerpc/platforms/powernv/setup.c > @@ -282,6 +282,57 @@ static void __init pnv_setup_machdep_rtas(void) > } > #endif /* CONFIG_PPC_POWERNV_RTAS */ > > +static unsigned int supported_cpuidle_states; > + > +unsigned int pnv_get_supported_cpuidle_states(void) > +{ > + return supported_cpuidle_states; > +} Will this be used by a module ? Doesn't it need to be exported ? Also keep the prefix pnv on the variable, I don't like globals with such a confusing name. > +static int __init pnv_probe_idle_states(void) > +{ > + struct device_node *power_mgt; > + struct property *prop; > + int dt_idle_states; > + u32 *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; > + } > + > + prop = of_find_property(power_mgt, "ibm,cpu-idle-state-flags", NULL); > + if (!prop) { > + pr_warn("DT-PowerMgmt: missing ibm,cpu-idle-state-flags\n"); > + return 0; > + } > + > + dt_idle_states = prop->length / sizeof(u32); > + flags = (u32 *) prop->value; > + > + for (i = 0; i < dt_idle_states; i++) { > + if (flags[i] & IDLE_INST_NAP) > + supported_cpuidle_states |= IDLE_USE_NAP; > + > + if (flags[i] & IDLE_INST_SLEEP) > + supported_cpuidle_states |= IDLE_USE_SLEEP; > + } > + > + return 0; > +} > + > +subsys_initcall(pnv_probe_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 5fcfcf4..3ad31d2 100644 > --- a/arch/powerpc/platforms/powernv/smp.c > +++ b/arch/powerpc/platforms/powernv/smp.c > @@ -149,6 +149,7 @@ static int pnv_smp_cpu_disable(void) > static void pnv_smp_cpu_kill_self(void) > { > unsigned int cpu; > + unsigned long idle_states; > > /* Standard hot unplug procedure */ > local_irq_disable(); > @@ -159,13 +160,21 @@ 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(); > - power7_nap(1); > + > + /* If sleep is supported, go to sleep, instead of nap */ > + if (idle_states & IDLE_USE_SLEEP) > + power7_sleep(); > + else > + power7_nap(1); > + > ppc64_runlatch_on(); > > /* Reenable IRQs briefly to clear the IPI that woke us */ > diff --git a/drivers/cpuidle/cpuidle-powernv.c b/drivers/cpuidle/cpuidle-powernv.c > index a64be57..23d2743 100644 > --- a/drivers/cpuidle/cpuidle-powernv.c > +++ b/drivers/cpuidle/cpuidle-powernv.c > @@ -16,13 +16,12 @@ > > #include <asm/machdep.h> > #include <asm/firmware.h> > +#include <asm/opal.h> > #include <asm/runlatch.h> > > /* Flags and constants used in PowerNV platform */ > > #define MAX_POWERNV_IDLE_STATES 8 > -#define IDLE_USE_INST_NAP 0x00010000 /* Use nap instruction */ > -#define IDLE_USE_INST_SLEEP 0x00020000 /* Use sleep instruction */ > > struct cpuidle_driver powernv_idle_driver = { > .name = "powernv_idle", > @@ -185,7 +184,7 @@ static int powernv_add_idle_states(void) > for (i = 0; i < dt_idle_states; i++) { > > flags = be32_to_cpu(idle_state_flags[i]); > - if (flags & IDLE_USE_INST_NAP) { > + if (flags & IDLE_INST_NAP) { > /* Add NAP state */ > strcpy(powernv_states[nr_idle_states].name, "Nap"); > strcpy(powernv_states[nr_idle_states].desc, "Nap"); > @@ -196,7 +195,7 @@ static int powernv_add_idle_states(void) > nr_idle_states++; > } > > - if (flags & IDLE_USE_INST_SLEEP) { > + if (flags & IDLE_INST_SLEEP) { > /* Add FASTSLEEP state */ > strcpy(powernv_states[nr_idle_states].name, "FastSleep"); > strcpy(powernv_states[nr_idle_states].desc, "FastSleep");
diff --git a/arch/powerpc/include/asm/opal.h b/arch/powerpc/include/asm/opal.h index 86055e5..28b8342 100644 --- a/arch/powerpc/include/asm/opal.h +++ b/arch/powerpc/include/asm/opal.h @@ -772,6 +772,10 @@ extern struct kobject *opal_kobj; /* /ibm,opal */ extern struct device_node *opal_node; +/* Flags used for idle state discovery from the device tree */ +#define IDLE_INST_NAP 0x00010000 /* nap instruction can be used */ +#define IDLE_INST_SLEEP 0x00020000 /* sleep instruction can be used */ + /* API functions */ int64_t opal_invalid_call(void); int64_t opal_console_write(int64_t term_number, __be64 *length, diff --git a/arch/powerpc/platforms/powernv/powernv.h b/arch/powerpc/platforms/powernv/powernv.h index 75501bf..31ece13 100644 --- a/arch/powerpc/platforms/powernv/powernv.h +++ b/arch/powerpc/platforms/powernv/powernv.h @@ -23,6 +23,13 @@ static inline int pnv_pci_dma_set_mask(struct pci_dev *pdev, u64 dma_mask) } #endif +/* Flags to indicate which of the CPU idle states are available for use */ + +#define IDLE_USE_NAP (1UL << 0) +#define IDLE_USE_SLEEP (1UL << 1) + +extern unsigned int 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 5a0e2dc..2dca1d8 100644 --- a/arch/powerpc/platforms/powernv/setup.c +++ b/arch/powerpc/platforms/powernv/setup.c @@ -282,6 +282,57 @@ static void __init pnv_setup_machdep_rtas(void) } #endif /* CONFIG_PPC_POWERNV_RTAS */ +static unsigned int supported_cpuidle_states; + +unsigned int pnv_get_supported_cpuidle_states(void) +{ + return supported_cpuidle_states; +} + +static int __init pnv_probe_idle_states(void) +{ + struct device_node *power_mgt; + struct property *prop; + int dt_idle_states; + u32 *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; + } + + prop = of_find_property(power_mgt, "ibm,cpu-idle-state-flags", NULL); + if (!prop) { + pr_warn("DT-PowerMgmt: missing ibm,cpu-idle-state-flags\n"); + return 0; + } + + dt_idle_states = prop->length / sizeof(u32); + flags = (u32 *) prop->value; + + for (i = 0; i < dt_idle_states; i++) { + if (flags[i] & IDLE_INST_NAP) + supported_cpuidle_states |= IDLE_USE_NAP; + + if (flags[i] & IDLE_INST_SLEEP) + supported_cpuidle_states |= IDLE_USE_SLEEP; + } + + return 0; +} + +subsys_initcall(pnv_probe_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 5fcfcf4..3ad31d2 100644 --- a/arch/powerpc/platforms/powernv/smp.c +++ b/arch/powerpc/platforms/powernv/smp.c @@ -149,6 +149,7 @@ static int pnv_smp_cpu_disable(void) static void pnv_smp_cpu_kill_self(void) { unsigned int cpu; + unsigned long idle_states; /* Standard hot unplug procedure */ local_irq_disable(); @@ -159,13 +160,21 @@ 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(); - power7_nap(1); + + /* If sleep is supported, go to sleep, instead of nap */ + if (idle_states & IDLE_USE_SLEEP) + power7_sleep(); + else + power7_nap(1); + ppc64_runlatch_on(); /* Reenable IRQs briefly to clear the IPI that woke us */ diff --git a/drivers/cpuidle/cpuidle-powernv.c b/drivers/cpuidle/cpuidle-powernv.c index a64be57..23d2743 100644 --- a/drivers/cpuidle/cpuidle-powernv.c +++ b/drivers/cpuidle/cpuidle-powernv.c @@ -16,13 +16,12 @@ #include <asm/machdep.h> #include <asm/firmware.h> +#include <asm/opal.h> #include <asm/runlatch.h> /* Flags and constants used in PowerNV platform */ #define MAX_POWERNV_IDLE_STATES 8 -#define IDLE_USE_INST_NAP 0x00010000 /* Use nap instruction */ -#define IDLE_USE_INST_SLEEP 0x00020000 /* Use sleep instruction */ struct cpuidle_driver powernv_idle_driver = { .name = "powernv_idle", @@ -185,7 +184,7 @@ static int powernv_add_idle_states(void) for (i = 0; i < dt_idle_states; i++) { flags = be32_to_cpu(idle_state_flags[i]); - if (flags & IDLE_USE_INST_NAP) { + if (flags & IDLE_INST_NAP) { /* Add NAP state */ strcpy(powernv_states[nr_idle_states].name, "Nap"); strcpy(powernv_states[nr_idle_states].desc, "Nap"); @@ -196,7 +195,7 @@ static int powernv_add_idle_states(void) nr_idle_states++; } - if (flags & IDLE_USE_INST_SLEEP) { + if (flags & IDLE_INST_SLEEP) { /* Add FASTSLEEP state */ strcpy(powernv_states[nr_idle_states].name, "FastSleep"); strcpy(powernv_states[nr_idle_states].desc, "FastSleep");