xtensa: drop platform_heartbeat

platform_heartbeat is called from the timer interrupt handler, but
there may be no periodic timer interrupts on xtensa, so the frequency of
platform_heartbeat calls may be unrelated to HZ. Drop the callback and
reimplement its only user with a timer.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

arch/xtensa/include/asm/platform.h

@@ -47,11 +47,6 @@ extern void platform_power_off (void);
  */
 extern void platform_idle (void);
 
-/*
- * platform_heartbeat is called every HZ
- */
-extern void platform_heartbeat (void);
-
 /*
  * platform_calibrate_ccount calibrates cpu clock freq (CONFIG_XTENSA_CALIBRATE)
  */

arch/xtensa/kernel/platform.c

@@ -32,7 +32,6 @@ _F(void, restart, (void), { while(1); });
 _F(void, halt, (void), { while(1); });
 _F(void, power_off, (void), { while(1); });
 _F(void, idle, (void), { __asm__ __volatile__ ("waiti 0" ::: "memory"); });
-_F(void, heartbeat, (void), { });
 
 #ifdef CONFIG_XTENSA_CALIBRATE_CCOUNT
 _F(void, calibrate_ccount, (void),

arch/xtensa/kernel/time.c

@@ -121,10 +121,6 @@ static irqreturn_t timer_interrupt(int irq, void *dev_id)
 
 	set_linux_timer(get_linux_timer());
 	evt->event_handler(evt);
-
-	/* Allow platform to do something useful (Wdog). */
-	platform_heartbeat();
-
 	return IRQ_HANDLED;
 }
 

arch/xtensa/platforms/xt2000/setup.c

@@ -23,6 +23,7 @@
 #include <linux/platform_device.h>
 #include <linux/serial.h>
 #include <linux/serial_8250.h>
+#include <linux/timer.h>
 
 #include <asm/processor.h>
 #include <asm/platform.h>
@@ -70,16 +71,17 @@ void __init platform_setup(char** cmdline)
 
 /* Heartbeat. Let the LED blink. */
 
-void platform_heartbeat(void)
+static void xt2000_heartbeat(struct timer_list *unused);
+
+static DEFINE_TIMER(heartbeat_timer, xt2000_heartbeat);
+
+static void xt2000_heartbeat(struct timer_list *unused)
 {
-	static int i, t;
+	static int i;
 
-	if (--t < 0)
-	{
-		t = 59;
-		led_print(7, i ? ".": " ");
-		i ^= 1;
-	}
+	led_print(7, i ? "." : " ");
+	i ^= 1;
+	mod_timer(&heartbeat_timer, jiffies + HZ / 2);
 }
 
 //#define RS_TABLE_SIZE 2
@@ -137,7 +139,7 @@ static int __init xt2000_setup_devinit(void)
 {
 	platform_device_register(&xt2000_serial8250_device);
 	platform_device_register(&xt2000_sonic_device);
-
+	mod_timer(&heartbeat_timer, jiffies + HZ / 2);
 	return 0;
 }