Messages in this thread | | | Subject | Re: [RFC] Support stop state version quirk and firmware enabled stop | From | Pratik Sampat <> | Date | Sun, 12 Apr 2020 17:36:37 +0530 |
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Hello Gautham,
On 08/04/20 3:20 pm, Gautham R Shenoy wrote: > Hi Pratik, > > On Wed, Mar 04, 2020 at 09:26:48PM +0530, Pratik Rajesh Sampat wrote: >> A concept patch in Skiboot to illustrate the case wherein handling of >> stop states for different DD versions of a CPU can be achieved by a >> simple modification in the list of cpu_features. >> As an example idle-stop1 is defined which uses P9_CPU_DD1 to define the >> cpu feature. >> >> Along with that, an implementation is being worked upon the LE OPAL >> series which helps OPAL handle the stop state entry and exit. >> >> This patch advertises this capability of the firmware which can be >> availed if the quirk-version-setting is not cognizable. >> >> The firmware-enabled stop is being worked by Abhishek Goel >> <huntbag@linux.vnet.ibm.com> building upon the LE OPAL series. >> >> Signed-off-by: Pratik Rajesh Sampat <psampat@linux.ibm.com> >> --- >> core/cpufeatures.c | 22 ++++++++++++++++++++++ >> 1 file changed, 22 insertions(+) >> >> diff --git a/core/cpufeatures.c b/core/cpufeatures.c >> index ec30c975..b9875e7b 100644 >> --- a/core/cpufeatures.c >> +++ b/core/cpufeatures.c >> @@ -510,6 +510,25 @@ static const struct cpu_feature cpu_features_table[] = { >> -1, -1, -1, >> NULL, }, >> >> + /* >> + * QUIRK for ISAv3.0B stop idle instructions and registers >> + * Helps us determine if there are any quirks >> + * XXX: Same of idle-stop >> + */ >> + { "idle-stop-v1", >> + CPU_P9_DD1, >> + ISA_V3_0B, USABLE_HV|USABLE_OS, >> + HV_CUSTOM, OS_CUSTOM, >> + -1, -1, -1, >> + NULL, }, > > So, at this point, we don't need any such quirk for any of the DD > version right ? This is to demonstrate that if say P9_DD1 had a quirk > w.r.t stop-state handling, then this is how we would advertise it to > the kernel.
Absolutely, A dummy property has been added to show how quirk handling with stop-states.
>> + >> + { "firmware-stop-supported", >> + CPU_P9, >> + ISA_V3_0B, USABLE_HV|USABLE_OS, >> + HV_CUSTOM, OS_CUSTOM, >> + -1, -1, -1, >> + NULL, }, >> + > > I suppose this is for the opal-cpuidle driver support posted here: > https://lists.ozlabs.org/pipermail/skiboot/2020-April/016726.html
Right, this complements in usage of the opal-cpuidle driver
>> /* >> * ISAv3.0B Hypervisor Virtualization Interrupt >> * Also associated system registers, LPCR EE, HEIC, HVICE, >> @@ -883,6 +902,9 @@ static void add_cpufeatures(struct dt_node *cpus, >> const struct cpu_feature *f = &cpu_features_table[i]; >> >> if (f->cpus_supported & cpu_feature_cpu) { >> + if (!strcmp(f->name, "firmware-stop-supported") && >> + HAVE_BIG_ENDIAN) >> + continue; > In OPAL do we have an macro defining BIG_ENDIAN ? If yes, you could > wrap the "firmware-stop-supported" in cpu_features_table[] within > #ifndef BIG_ENDIAN. That way you won't need a special case here. > HAVE_BIG_ENDIAN is actually a macro. Its a good idea to wrap it in the declaration itself.
> >> DBG(" '%s'\n", f->name); >> add_cpu_feature_nodeps(features, f); >> } >> -- >> 2.24.1 >> > -- > Thanks and Regards > gautham.
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