[Skiboot] [RFC 2/2] opal : Introducing capability for firmware-stop-support

[Abhishek Goel]

This patch introduces support for firmware-stop-support. If Kernel does
not know about stop version, it can fallback to opal for idle stop
support if firmware-stop-supported property is present.

Just like "idle-stop", "idle-stop-quirk" can be defined in features if
there is some quirk that needs to be handled and if kernel identifies
the corresponding version it can use that or fallback to opal for idle
stop support.

The complete idea was previosuly posted in this patch:
https://patchwork.ozlabs.org/project/skiboot/list/?series=162400

Signed-off-by: Pratik Rajesh Sampat <psampat at linux.ibm.com>
Signed-off-by: Abhishek Goel <huntbag at linux.vnet.ibm.com>
---

 v1->v2 : This patch has been newly added in this series.

 core/cpufeatures.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/core/cpufeatures.c b/core/cpufeatures.c
index c6754abb..1f516028 100644
--- a/core/cpufeatures.c
+++ b/core/cpufeatures.c
@@ -510,6 +510,19 @@ static const struct cpu_feature cpu_features_table[] = {
 	-1, -1, -1,
 	NULL, },
 
+	/*
+	 * ISAv3.0B firmware-stop-support
+	 * Opal fallback for shallow stop states
+	 */
+#ifdef HAVE_BIG_ENDIAN
+	{ "firmware-stop-supported",
+	CPU_P9,
+	ISA_V3_0B, USABLE_HV|USABLE_OS,
+	HV_CUSTOM, OS_CUSTOM,
+	-1, -1, -1,
+	NULL, },
+#endif
+
 	/*
 	 * ISAv3.0B Hypervisor Virtualization Interrupt
 	 * Also associated system registers, LPCR EE, HEIC, HVICE,
-- 
2.17.1