x86: GEODE: MFGPT: Use "just-in-time" detection for the MFGPT timers

There isn't much value to always detecting the MFGPT timers on
Geode platforms; detection is only needed when something wants
to use the timers.  Move the detection code so that it gets
called the first time a timer is allocated.
Signed-off-by: Jordan Crouse <jordan.crouse@amd.com>
Signed-off-by: Andres Salomon <dilinger@debian.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/kernel/geode_32.c

@@ -163,14 +163,11 @@ EXPORT_SYMBOL_GPL(geode_gpio_setup_event);
 
 static int __init geode_southbridge_init(void)
 {
-	int timers;
-
 	if (!is_geode())
 		return -ENODEV;
 
 	init_lbars();
-	timers = geode_mfgpt_detect();
-	printk(KERN_INFO "geode:  %d MFGPT timers available.\n", timers);
+	(void) mfgpt_timer_setup();
 	return 0;
 }
 

arch/x86/kernel/mfgpt_32.c

@@ -74,28 +74,37 @@ __setup("mfgptfix", mfgpt_fix);
  * In other cases (such as with VSAless OpenFirmware), the system firmware
  * leaves timers available for us to use.
  */
-int __init geode_mfgpt_detect(void)
+
+
+static int timers = -1;
+
+static void geode_mfgpt_detect(void)
 {
-	int count = 0, i;
+	int i;
 	u16 val;
 
+	timers = 0;
+
 	if (disable) {
-		printk(KERN_INFO "geode-mfgpt:  Skipping MFGPT setup\n");
-		return 0;
+		printk(KERN_INFO "geode-mfgpt:  MFGPT support is disabled\n");
+		goto done;
+	}
+
+	if (!geode_get_dev_base(GEODE_DEV_MFGPT)) {
+		printk(KERN_INFO "geode-mfgpt:  MFGPT LBAR is not set up\n");
+		goto done;
 	}
 
 	for (i = 0; i < MFGPT_MAX_TIMERS; i++) {
 		val = geode_mfgpt_read(i, MFGPT_REG_SETUP);
 		if (!(val & MFGPT_SETUP_SETUP)) {
 			mfgpt_timers[i].avail = 1;
-			count++;
+			timers++;
 		}
 	}
 
-	/* set up clock event device, if desired */
-	i = mfgpt_timer_setup();
-
-	return count;
+done:
+	printk(KERN_INFO "geode-mfgpt:  %d MFGPT timers available.\n", timers);
 }
 
 int geode_mfgpt_toggle_event(int timer, int cmp, int event, int enable)
@@ -183,10 +192,16 @@ int geode_mfgpt_alloc_timer(int timer, int domain)
 {
 	int i;
 
-	if (!geode_get_dev_base(GEODE_DEV_MFGPT))
-		return -ENODEV;
+	if (timers == -1) {
+		/* timers haven't been detected yet */
+		geode_mfgpt_detect();
+	}
+
+	if (!timers)
+		return -1;
+
 	if (timer >= MFGPT_MAX_TIMERS)
-		return -EIO;
+		return -1;
 
 	if (timer < 0) {
 		/* Try to find an available timer */

include/asm-x86/geode.h

@@ -206,7 +206,6 @@ static inline u16 geode_mfgpt_read(int timer, u16 reg)
 	return inw(base + reg + (timer * 8));
 }
 
-extern int __init geode_mfgpt_detect(void);
 extern int geode_mfgpt_toggle_event(int timer, int cmp, int event, int enable);
 extern int geode_mfgpt_set_irq(int timer, int cmp, int irq, int enable);
 extern int geode_mfgpt_alloc_timer(int timer, int domain);