From: Gautham R Shenoy <ego@linux.vnet.ibm.com> To: Abhishek Goel <huntbag@linux.vnet.ibm.com> Cc: linuxppc-dev@ozlabs.org, linux-kernel@vger.kernel.org, npiggin@gmail.com, ego@linux.vnet.ibm.com, svaidy@linux.ibm.com, mpe@ellerman.id.au, oohall@gmail.com, mikey@neuling.org, psampat@linux.ibm.com Subject: Re: [RFC 3/3] powernv/cpuidle : Introduce capability for firmware-enabled-stop Date: Mon, 27 Apr 2020 19:18:40 +0530 [thread overview] Message-ID: <20200427134840.GE29708@in.ibm.com> (raw) In-Reply-To: <20200427021027.114582-3-huntbag@linux.vnet.ibm.com> On Sun, Apr 26, 2020 at 09:10:27PM -0500, Abhishek Goel wrote: > This patch introduces the capability for firmware to handle the stop > states instead. A bit is set based on the discovery of the feature > and correspondingly also the responsibility to handle the stop states. > > If Kernel does not know about stop version, it can fallback to opal for > idle stop support if firmware-stop-supported property is present. > > Earlier this patch was posted as part of this series : > https://lkml.org/lkml/2020/3/4/589 > > Signed-off-by: Pratik Rajesh Sampat <psampat@linux.ibm.com> > Signed-off-by: Abhishek Goel <huntbag@linux.vnet.ibm.com> > --- > > v1->v2: This patch is newly added in this series. > > arch/powerpc/include/asm/processor.h | 1 + > arch/powerpc/kernel/dt_cpu_ftrs.c | 8 ++++++++ > arch/powerpc/platforms/powernv/idle.c | 27 ++++++++++++++++----------- > 3 files changed, 25 insertions(+), 11 deletions(-) > > diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h > index 66fa20476d0e..d5c6532b11ef 100644 > --- a/arch/powerpc/include/asm/processor.h > +++ b/arch/powerpc/include/asm/processor.h > @@ -430,6 +430,7 @@ extern unsigned long cpuidle_disable; > enum idle_boot_override {IDLE_NO_OVERRIDE = 0, IDLE_POWERSAVE_OFF}; > > #define STOP_ENABLE 0x00000001 > +#define FIRMWARE_STOP_ENABLE 0x00000010 > > #define STOP_VERSION_P9 0x1 > > diff --git a/arch/powerpc/kernel/dt_cpu_ftrs.c b/arch/powerpc/kernel/dt_cpu_ftrs.c > index db1a525e090d..ff4a87b79702 100644 > --- a/arch/powerpc/kernel/dt_cpu_ftrs.c > +++ b/arch/powerpc/kernel/dt_cpu_ftrs.c > @@ -298,6 +298,13 @@ static int __init feat_enable_idle_stop(struct dt_cpu_feature *f) > return 1; > } > > +static int __init feat_enable_firmware_stop(struct dt_cpu_feature *f) > +{ > + stop_dep.cpuidle_prop |= FIRMWARE_STOP_ENABLE; > + > + return 1; > +} > + > static int __init feat_enable_mmu_hash(struct dt_cpu_feature *f) > { > u64 lpcr; > @@ -592,6 +599,7 @@ static struct dt_cpu_feature_match __initdata > {"idle-nap", feat_enable_idle_nap, 0}, > {"alignment-interrupt-dsisr", feat_enable_align_dsisr, 0}, > {"idle-stop", feat_enable_idle_stop, 0}, > + {"firmware-stop-supported", feat_enable_firmware_stop, 0}, > {"machine-check-power8", feat_enable_mce_power8, 0}, > {"performance-monitor-power8", feat_enable_pmu_power8, 0}, > {"data-stream-control-register", feat_enable_dscr, CPU_FTR_DSCR}, > diff --git a/arch/powerpc/platforms/powernv/idle.c b/arch/powerpc/platforms/powernv/idle.c > index 538f0842ac3f..0de5de81902e 100644 > --- a/arch/powerpc/platforms/powernv/idle.c > +++ b/arch/powerpc/platforms/powernv/idle.c > @@ -633,16 +633,6 @@ static unsigned long power9_idle_stop(unsigned long psscr, bool mmu_on) > unsigned long mmcr0 = 0; > struct p9_sprs sprs = {}; /* avoid false used-uninitialised */ > bool sprs_saved = false; > - int rc = 0; > - > - /* > - * Kernel takes decision whether to make OPAL call or not. This logic > - * will be combined with the logic for BE opal to take decision. > - */ > - if (firmware_stop_supported) { > - rc = opal_cpu_idle(cpu_to_be64(__pa(&srr1)), (uint64_t) psscr); > - goto out; > - } > > if (!(psscr & (PSSCR_EC|PSSCR_ESL))) { > /* EC=ESL=0 case */ > @@ -835,6 +825,19 @@ static unsigned long power9_idle_stop(unsigned long psscr, bool mmu_on) > return srr1; > } > > +static unsigned long power9_firmware_idle_stop(unsigned long psscr, bool mmu_on) > +{ > + unsigned long srr1; > + int rc; > + > + rc = opal_cpu_idle(cpu_to_be64(__pa(&srr1)), (uint64_t) psscr); > + > + if (mmu_on) > + mtmsr(MSR_KERNEL); > + return srr1; > + > +} > + > #ifdef CONFIG_HOTPLUG_CPU > static unsigned long power9_offline_stop(unsigned long psscr) > { > @@ -1394,9 +1397,11 @@ static int __init pnv_init_idle_states(void) > !(stop_dep.cpuidle_prop & STOP_ENABLE)) > goto out; > > - /* Check for supported version in kernel */ > + /* Check for supported version in kernel or fallback to kernel*/ > if (stop_dep.stop_version & STOP_VERSION_P9) { > stop_dep.idle_stop = power9_idle_stop; > + } else if (stop_dep.cpuidle_prop & FIRMWARE_STOP_ENABLE) { > + stop_dep.idle_stop = power9_firmware_idle_stop; Ok, so in this patch you first check if the "idle-stop" feature is available. Only otherwise you fallback to the OPAL based cpuidle driver. This looks ok to me. > } else { > stop_dep.idle_stop = NULL; > goto out; > -- > 2.17.1 > -- Thanks and Regards gautham.
WARNING: multiple messages have this Message-ID (diff)
From: Gautham R Shenoy <ego@linux.vnet.ibm.com> To: Abhishek Goel <huntbag@linux.vnet.ibm.com> Cc: ego@linux.vnet.ibm.com, mikey@neuling.org, linux-kernel@vger.kernel.org, npiggin@gmail.com, linuxppc-dev@ozlabs.org, oohall@gmail.com, psampat@linux.ibm.com Subject: Re: [RFC 3/3] powernv/cpuidle : Introduce capability for firmware-enabled-stop Date: Mon, 27 Apr 2020 19:18:40 +0530 [thread overview] Message-ID: <20200427134840.GE29708@in.ibm.com> (raw) In-Reply-To: <20200427021027.114582-3-huntbag@linux.vnet.ibm.com> On Sun, Apr 26, 2020 at 09:10:27PM -0500, Abhishek Goel wrote: > This patch introduces the capability for firmware to handle the stop > states instead. A bit is set based on the discovery of the feature > and correspondingly also the responsibility to handle the stop states. > > If Kernel does not know about stop version, it can fallback to opal for > idle stop support if firmware-stop-supported property is present. > > Earlier this patch was posted as part of this series : > https://lkml.org/lkml/2020/3/4/589 > > Signed-off-by: Pratik Rajesh Sampat <psampat@linux.ibm.com> > Signed-off-by: Abhishek Goel <huntbag@linux.vnet.ibm.com> > --- > > v1->v2: This patch is newly added in this series. > > arch/powerpc/include/asm/processor.h | 1 + > arch/powerpc/kernel/dt_cpu_ftrs.c | 8 ++++++++ > arch/powerpc/platforms/powernv/idle.c | 27 ++++++++++++++++----------- > 3 files changed, 25 insertions(+), 11 deletions(-) > > diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h > index 66fa20476d0e..d5c6532b11ef 100644 > --- a/arch/powerpc/include/asm/processor.h > +++ b/arch/powerpc/include/asm/processor.h > @@ -430,6 +430,7 @@ extern unsigned long cpuidle_disable; > enum idle_boot_override {IDLE_NO_OVERRIDE = 0, IDLE_POWERSAVE_OFF}; > > #define STOP_ENABLE 0x00000001 > +#define FIRMWARE_STOP_ENABLE 0x00000010 > > #define STOP_VERSION_P9 0x1 > > diff --git a/arch/powerpc/kernel/dt_cpu_ftrs.c b/arch/powerpc/kernel/dt_cpu_ftrs.c > index db1a525e090d..ff4a87b79702 100644 > --- a/arch/powerpc/kernel/dt_cpu_ftrs.c > +++ b/arch/powerpc/kernel/dt_cpu_ftrs.c > @@ -298,6 +298,13 @@ static int __init feat_enable_idle_stop(struct dt_cpu_feature *f) > return 1; > } > > +static int __init feat_enable_firmware_stop(struct dt_cpu_feature *f) > +{ > + stop_dep.cpuidle_prop |= FIRMWARE_STOP_ENABLE; > + > + return 1; > +} > + > static int __init feat_enable_mmu_hash(struct dt_cpu_feature *f) > { > u64 lpcr; > @@ -592,6 +599,7 @@ static struct dt_cpu_feature_match __initdata > {"idle-nap", feat_enable_idle_nap, 0}, > {"alignment-interrupt-dsisr", feat_enable_align_dsisr, 0}, > {"idle-stop", feat_enable_idle_stop, 0}, > + {"firmware-stop-supported", feat_enable_firmware_stop, 0}, > {"machine-check-power8", feat_enable_mce_power8, 0}, > {"performance-monitor-power8", feat_enable_pmu_power8, 0}, > {"data-stream-control-register", feat_enable_dscr, CPU_FTR_DSCR}, > diff --git a/arch/powerpc/platforms/powernv/idle.c b/arch/powerpc/platforms/powernv/idle.c > index 538f0842ac3f..0de5de81902e 100644 > --- a/arch/powerpc/platforms/powernv/idle.c > +++ b/arch/powerpc/platforms/powernv/idle.c > @@ -633,16 +633,6 @@ static unsigned long power9_idle_stop(unsigned long psscr, bool mmu_on) > unsigned long mmcr0 = 0; > struct p9_sprs sprs = {}; /* avoid false used-uninitialised */ > bool sprs_saved = false; > - int rc = 0; > - > - /* > - * Kernel takes decision whether to make OPAL call or not. This logic > - * will be combined with the logic for BE opal to take decision. > - */ > - if (firmware_stop_supported) { > - rc = opal_cpu_idle(cpu_to_be64(__pa(&srr1)), (uint64_t) psscr); > - goto out; > - } > > if (!(psscr & (PSSCR_EC|PSSCR_ESL))) { > /* EC=ESL=0 case */ > @@ -835,6 +825,19 @@ static unsigned long power9_idle_stop(unsigned long psscr, bool mmu_on) > return srr1; > } > > +static unsigned long power9_firmware_idle_stop(unsigned long psscr, bool mmu_on) > +{ > + unsigned long srr1; > + int rc; > + > + rc = opal_cpu_idle(cpu_to_be64(__pa(&srr1)), (uint64_t) psscr); > + > + if (mmu_on) > + mtmsr(MSR_KERNEL); > + return srr1; > + > +} > + > #ifdef CONFIG_HOTPLUG_CPU > static unsigned long power9_offline_stop(unsigned long psscr) > { > @@ -1394,9 +1397,11 @@ static int __init pnv_init_idle_states(void) > !(stop_dep.cpuidle_prop & STOP_ENABLE)) > goto out; > > - /* Check for supported version in kernel */ > + /* Check for supported version in kernel or fallback to kernel*/ > if (stop_dep.stop_version & STOP_VERSION_P9) { > stop_dep.idle_stop = power9_idle_stop; > + } else if (stop_dep.cpuidle_prop & FIRMWARE_STOP_ENABLE) { > + stop_dep.idle_stop = power9_firmware_idle_stop; Ok, so in this patch you first check if the "idle-stop" feature is available. Only otherwise you fallback to the OPAL based cpuidle driver. This looks ok to me. > } else { > stop_dep.idle_stop = NULL; > goto out; > -- > 2.17.1 > -- Thanks and Regards gautham.
next prev parent reply other threads:[~2020-04-27 13:48 UTC|newest] Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-04-27 2:10 [RFC 1/3] powernv/cpuidle : Support for pre-entry and post exit of stop state in firmware Abhishek Goel 2020-04-27 2:10 ` Abhishek Goel 2020-04-27 2:10 ` [RFC 2/3] powernv/cpuidle : Interface for an idle-stop dependency structure Abhishek Goel 2020-04-27 2:10 ` Abhishek Goel 2020-04-27 13:47 ` Gautham R Shenoy 2020-04-27 13:47 ` Gautham R Shenoy 2020-05-05 6:57 ` kbuild test robot 2020-04-27 2:10 ` [RFC 3/3] powernv/cpuidle : Introduce capability for firmware-enabled-stop Abhishek Goel 2020-04-27 2:10 ` Abhishek Goel 2020-04-27 13:48 ` Gautham R Shenoy [this message] 2020-04-27 13:48 ` Gautham R Shenoy 2020-04-27 10:26 ` [RFC 1/3] powernv/cpuidle : Support for pre-entry and post exit of stop state in firmware Gautham R Shenoy 2020-04-27 10:26 ` Gautham R Shenoy 2020-04-28 1:08 ` Nicholas Piggin 2020-04-28 1:08 ` Nicholas Piggin 2020-04-30 5:52 ` Abhishek 2020-04-30 5:52 ` Abhishek 2020-05-02 11:40 ` Nicholas Piggin 2020-05-02 11:40 ` Nicholas Piggin
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