[PATCH] powerpc: enable NAP only on cpus who support it to avoid memory corruption

This patch fixes incorrect setting of powersave_nap to 1 on all
PowerMacs, potentially causing memory corruption on some models. This
bug was introuced by me during the 32/64 bits merge.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/platforms/powermac/feature.c

@@ -2491,9 +2491,7 @@ static int __init probe_motherboard(void)
 			pmac_mb.model_id = PMAC_TYPE_COMET;
 		iounmap(mach_id_ptr);
 	}
-#endif /* CONFIG_POWER4 */
 
-#ifdef CONFIG_6xx
 	/* Set default value of powersave_nap on machines that support it.
 	 * It appears that uninorth rev 3 has a problem with it, we don't
 	 * enable it on those. In theory, the flush-on-lock property is
@@ -2522,10 +2520,11 @@ static int __init probe_motherboard(void)
 	 * NAP mode
 	 */
 	powersave_lowspeed = 1;
-#endif /* CONFIG_6xx */
-#ifdef CONFIG_POWER4
+
+#else /* CONFIG_POWER4 */
 	powersave_nap = 1;
-#endif
+#endif  /* CONFIG_POWER4 */
+
 	/* Check for "mobile" machine */
 	if (model && (strncmp(model, "PowerBook", 9) == 0
 		   || strncmp(model, "iBook", 5) == 0))

arch/powerpc/platforms/powermac/setup.c

@@ -621,10 +621,6 @@ static void __init pmac_init_early(void)
 	/* Probe motherboard chipset */
 	pmac_feature_init();
 
-	/* We can NAP */
-	powersave_nap = 1;
-	printk(KERN_INFO "Using native/NAP idle loop\n");
-
 	/* Initialize debug stuff */
 	udbg_scc_init(!!strstr(cmd_line, "sccdbg"));
 	udbg_adb_init(!!strstr(cmd_line, "btextdbg"));