DaVinci: update CPU detection so compiler can optimize away

Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>

arch/arm/mach-davinci/id.c

@@ -17,6 +17,8 @@
 
 #define JTAG_ID_BASE		0x01c40028
 
+static unsigned int davinci_revision;
+
 struct davinci_id {
 	u8	variant;	/* JTAG ID bits 31:28 */
 	u16	part_no;	/* JTAG ID bits 27:12 */
@@ -77,6 +79,11 @@ static u8 __init davinci_get_variant(void)
 	return variant;
 }
 
+unsigned int davinci_rev(void)
+{
+	return davinci_revision >> 16;
+}
+
 void __init davinci_check_revision(void)
 {
 	int i;
@@ -89,7 +96,7 @@ void __init davinci_check_revision(void)
 	/* First check only the major version in a safe way */
 	for (i = 0; i < ARRAY_SIZE(davinci_ids); i++) {
 		if (part_no == (davinci_ids[i].part_no)) {
-			system_rev = davinci_ids[i].type;
+			davinci_revision = davinci_ids[i].type;
 			break;
 		}
 	}
@@ -98,10 +105,11 @@ void __init davinci_check_revision(void)
 	for (i = 0; i < ARRAY_SIZE(davinci_ids); i++) {
 		if (part_no == davinci_ids[i].part_no &&
 		    variant == davinci_ids[i].variant) {
-			system_rev = davinci_ids[i].type;
+			davinci_revision = davinci_ids[i].type;
 			break;
 		}
 	}
 
-	printk("DaVinci DM%04x variant 0x%x\n", system_rev >> 16, variant);
+	printk(KERN_INFO "DaVinci DM%04x variant 0x%x\n",
+	       davinci_rev(), variant);
 }

arch/arm/mach-davinci/include/mach/cpu.h

 /*
- * linux/include/asm-arm/arch-davinci/cpu.h
+ * DaVinci CPU type detection
  *
- * Davinci cpu type detection
+ * Author: Kevin Hilman, Deep Root Systems, LLC
  *
- * Author: Steve Chen <schen@mvista.com>
+ * Defines the cpu_is_*() macros for runtime detection of DaVinci
+ * device type.  In addtion, if support for a given device is not
+ * compiled in to the kernel, the macros return 0 so that
+ * resulting code can be optimized out.
  *
- * 2007 (c) MontaVista Software, Inc. This file is licensed under
+ * 2007 (c) Deep Root Systems, LLC. This file is licensed under
  * the terms of the GNU General Public License version 2. This program
  * is licensed "as is" without any warranty of any kind, whether express
  * or implied.
  */
-
 #ifndef _ASM_ARCH_CPU_H
 #define _ASM_ARCH_CPU_H
 
-extern unsigned int system_rev;
-
-#define GET_DAVINCI_CPU_TYPE	((system_rev >> 16) & 0xffff)
+extern unsigned int davinci_rev(void);
 
 #define IS_DAVINCI_CPU(type, id)			\
-static inline int cpu_is_davinci_dm ##type (void)	\
+static inline int is_davinci_dm ##type(void)	        \
 {							\
-        return (GET_DAVINCI_CPU_TYPE == (id)) ? 1 : 0;	\
+	return (davinci_rev() == (id)) ? 1 : 0;	        \
 }
 
-/* following generates the cpu_is_davinci_dmxxx */
-IS_DAVINCI_CPU(644x, 0x6446)	/* cpu_is_davinci_dm644x() */
-IS_DAVINCI_CPU(646x, 0x6467)	/* cpu_is_davinci_dm646x() */
-IS_DAVINCI_CPU(355, 0x355)	/* cpu_is_davinci_dm355() */
+IS_DAVINCI_CPU(644x, 0x6446)
+IS_DAVINCI_CPU(646x, 0x6467)
+IS_DAVINCI_CPU(355, 0x355)
+
+#ifdef CONFIG_ARCH_DAVINCI_DM644x
+#define cpu_is_davinci_dm644x() is_davinci_dm644x()
+#else
+#define cpu_is_davinci_dm644x() 0
+#endif
+
+#ifdef CONFIG_ARCH_DAVINCI_DM646x
+#define cpu_is_davinci_dm646x() is_davinci_dm646x()
+#else
+#define cpu_is_davinci_dm646x() 0
+#endif
+
+#ifdef CONFIG_ARCH_DAVINCI_DM355
+#define cpu_is_davinci_dm355() is_davinci_dm355()
+#else
+#define cpu_is_davinci_dm355() 0
+#endif
 
 #endif