powerpc/pseries: Cleanup best_energy_hcall detection

Currently we search for the best_energy hcall using a custom function.  Move
this to using the firmware_feature_table.

Signed-off-by: Michael Neuling <mikey@neuling.org>
cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
cc: Linux PPC dev <linuxppc-dev@ozlabs.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/include/asm/firmware.h

@@ -50,6 +50,7 @@
 #define FW_FEATURE_OPAL		ASM_CONST(0x0000000010000000)
 #define FW_FEATURE_OPALv2	ASM_CONST(0x0000000020000000)
 #define FW_FEATURE_SET_MODE	ASM_CONST(0x0000000040000000)
+#define FW_FEATURE_BEST_ENERGY	ASM_CONST(0x0000000080000000)
 
 #ifndef __ASSEMBLY__
 
@@ -64,7 +65,7 @@ enum {
 		FW_FEATURE_BULK_REMOVE | FW_FEATURE_XDABR |
 		FW_FEATURE_MULTITCE | FW_FEATURE_SPLPAR | FW_FEATURE_LPAR |
 		FW_FEATURE_CMO | FW_FEATURE_VPHN | FW_FEATURE_XCMO |
-		FW_FEATURE_SET_MODE,
+		FW_FEATURE_SET_MODE | FW_FEATURE_BEST_ENERGY,
 	FW_FEATURE_PSERIES_ALWAYS = 0,
 	FW_FEATURE_POWERNV_POSSIBLE = FW_FEATURE_OPAL | FW_FEATURE_OPALv2,
 	FW_FEATURE_POWERNV_ALWAYS = 0,

arch/powerpc/platforms/pseries/firmware.c

@@ -62,6 +62,7 @@ firmware_features_table[FIRMWARE_MAX_FEATURES] = {
 	{FW_FEATURE_SPLPAR,		"hcall-splpar"},
 	{FW_FEATURE_VPHN,		"hcall-vphn"},
 	{FW_FEATURE_SET_MODE,		"hcall-set-mode"},
+	{FW_FEATURE_BEST_ENERGY,	"hcall-best-energy-1*"},
 };
 
 /* Build up the firmware features bitmask using the contents of

arch/powerpc/platforms/pseries/pseries_energy.c

@@ -21,6 +21,7 @@
 #include <asm/cputhreads.h>
 #include <asm/page.h>
 #include <asm/hvcall.h>
+#include <asm/firmware.h>
 
 
 #define MODULE_VERS "1.0"
@@ -32,40 +33,6 @@ static int sysfs_entries;
 
 /* Helper routines */
 
-/*
- * Routine to detect firmware support for hcall
- * return 1 if H_BEST_ENERGY is supported
- * else return 0
- */
-
-static int check_for_h_best_energy(void)
-{
-	struct device_node *rtas = NULL;
-	const char *hypertas, *s;
-	int length;
-	int rc = 0;
-
-	rtas = of_find_node_by_path("/rtas");
-	if (!rtas)
-		return 0;
-
-	hypertas = of_get_property(rtas, "ibm,hypertas-functions", &length);
-	if (!hypertas) {
-		of_node_put(rtas);
-		return 0;
-	}
-
-	/* hypertas will have list of strings with hcall names */
-	for (s = hypertas; s < hypertas + length; s += strlen(s) + 1) {
-		if (!strncmp("hcall-best-energy-1", s, 19)) {
-			rc = 1; /* Found the string */
-			break;
-		}
-	}
-	of_node_put(rtas);
-	return rc;
-}
-
 /* Helper Routines to convert between drc_index to cpu numbers */
 
 static u32 cpu_to_drc_index(int cpu)
@@ -262,7 +229,7 @@ static int __init pseries_energy_init(void)
 	int cpu, err;
 	struct device *cpu_dev;
 
-	if (!check_for_h_best_energy()) {
+	if (!firmware_has_feature(FW_FEATURE_BEST_ENERGY)) {
 		printk(KERN_INFO "Hypercall H_BEST_ENERGY not supported\n");
 		return 0;
 	}