[Skiboot] [RFC v2 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: Abhishek Goel <huntbag at linux.vnet.ibm.com>
Signed-off-by: Pratik Rajesh Sampat <psampat at linux.ibm.com>
---
 v1->v2 : No changes in this patch.

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

diff --git a/core/cpufeatures.c b/core/cpufeatures.c
index c6754abb..a8de2baa 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_LITTLE_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