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OMAP2PLUS: WDT: Fix: Disable WDT after reset during init

Message ID 1285834270-32766-1-git-send-email-charu@ti.com (mailing list archive)
State Changes Requested, archived
Delegated to: Tony Lindgren
Headers show

Commit Message

charu@ti.com Sept. 30, 2010, 8:11 a.m. UTC
None
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Patch

diff --git a/arch/arm/mach-omap2/devices.c b/arch/arm/mach-omap2/devices.c
index 8e2f0aa..9f44fc6 100644
--- a/arch/arm/mach-omap2/devices.c
+++ b/arch/arm/mach-omap2/devices.c
@@ -916,11 +916,55 @@  static inline void omap_init_vout(void) {}
 
 /*-------------------------------------------------------------------------*/
 
+/*
+ * WDT mdoule is reset during init which enables the watchdog.
+ * Hence it is required to disable the watchdog after the WDT reset
+ * during init. Otherwise the system would reboot as per the default
+ * watchdog timer registers settings.
+ */
+#define OMAP_WDT_WPS	(0x34)
+#define OMAP_WDT_SPR	(0x48)
+
+static int omap2_disable_wdt(struct omap_hwmod *oh, void *user)
+{
+	void __iomem *base;
+
+	if (!oh)
+		pr_err("Could not look up wdtimer_hwmod\n");
+
+	base = oh->_mpu_rt_va;
+
+	/* Enable the clocks before accessing the WDT registers */
+	omap_hwmod_enable(oh);
+
+	/* sequence required to disable watchdog */
+	__raw_writel(0xAAAA, base + OMAP_WDT_SPR);	/* TIMER_MODE */
+	while (__raw_readl(base + OMAP_WDT_WPS) & 0x10)
+		cpu_relax();
+
+	__raw_writel(0x5555, base + OMAP_WDT_SPR);	/* TIMER_MODE */
+	while (__raw_readl(base + OMAP_WDT_WPS) & 0x10)
+		cpu_relax();
+
+	omap_hwmod_idle(oh);
+
+	return 0;
+}
+
+static void __init omap_disable_wdt(void)
+{
+	if (cpu_class_is_omap2())
+		omap_hwmod_for_each_by_class("wd_timer",
+						omap2_disable_wdt, NULL);
+	return;
+}
+
 static int __init omap2_init_devices(void)
 {
 	/* please keep these calls, and their implementations above,
 	 * in alphabetical order so they're easier to sort through.
 	 */
+	omap_disable_wdt();
 	omap_hsmmc_reset();
 	omap_init_camera();
 	omap_init_mbox();