powerpc/pseries: add FW_FEATURE_WATCHDOG flag

PAPR v2.12 specifies a new optional function set, "hcall-watchdog",
for the /rtas/ibm,hypertas-functions property.  The presence of this
function set indicates support for the H_WATCHDOG hypercall.

Check for this function set and, if present, set the new
FW_FEATURE_WATCHDOG flag.
Signed-off-by: Scott Cheloha <cheloha@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220713202335.1217647-3-cheloha@linux.ibm.com

arch/powerpc/include/asm/firmware.h

@@ -55,6 +55,7 @@
 #define FW_FEATURE_RPT_INVALIDATE ASM_CONST(0x0000010000000000)
 #define FW_FEATURE_FORM2_AFFINITY ASM_CONST(0x0000020000000000)
 #define FW_FEATURE_ENERGY_SCALE_INFO ASM_CONST(0x0000040000000000)
+#define FW_FEATURE_WATCHDOG	ASM_CONST(0x0000080000000000)
 
 #ifndef __ASSEMBLY__
 
@@ -76,7 +77,7 @@ enum {
 		FW_FEATURE_DRC_INFO | FW_FEATURE_BLOCK_REMOVE |
 		FW_FEATURE_PAPR_SCM | FW_FEATURE_ULTRAVISOR |
 		FW_FEATURE_RPT_INVALIDATE | FW_FEATURE_FORM2_AFFINITY |
-		FW_FEATURE_ENERGY_SCALE_INFO,
+		FW_FEATURE_ENERGY_SCALE_INFO | FW_FEATURE_WATCHDOG,
 	FW_FEATURE_PSERIES_ALWAYS = 0,
 	FW_FEATURE_POWERNV_POSSIBLE = FW_FEATURE_OPAL | FW_FEATURE_ULTRAVISOR,
 	FW_FEATURE_POWERNV_ALWAYS = 0,

arch/powerpc/platforms/pseries/firmware.c

@@ -67,6 +67,7 @@ hypertas_fw_features_table[] = {
 	{FW_FEATURE_PAPR_SCM,		"hcall-scm"},
 	{FW_FEATURE_RPT_INVALIDATE,	"hcall-rpt-invalidate"},
 	{FW_FEATURE_ENERGY_SCALE_INFO,	"hcall-energy-scale-info"},
+	{FW_FEATURE_WATCHDOG,		"hcall-watchdog"},
 };
 
 /* Build up the firmware features bitmask using the contents of