arm: tegra: power: add watchdog recovery function

Add watchdog recovery mechanism to protect against hangs during
driver suspend/resume sequence

Bug 857748

Change-Id: I03d540b38318a5a953b1a697af123291b48991e9
Signed-off-by: Kamal Kannan Balagopalan <kbalagopalan@nvidia.com>
Reviewed-on: http://git-master/r/65986
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Krishna Reddy <vdumpa@nvidia.com>

1 files changed, 131 insertions, 0 deletions

diff --git a/arch/arm/mach-tegra/wdt-recovery.c b/arch/arm/mach-tegra/wdt-recovery.c
new file mode 100644
index 000000000000..537b1c0db853
--- /dev/null
+++ b/arch/arm/mach-tegra/wdt-recovery.c
@@ -0,0 +1,131 @@
+/*
+ * arch/arm/mach-tegra/wdt-recovery.c
+ *
+ * Copyright (c) 2011, NVIDIA Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+
+#include <linux/kernel.h>
+#include <linux/delay.h>
+#include <linux/suspend.h>
+#include <linux/resource.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/syscore_ops.h>
+#include <linux/io.h>
+
+#include <asm/mach-types.h>
+#include <asm/mach/time.h>
+#include <asm/localtimer.h>
+
+#include <mach/nvmap.h>
+#include <mach/irqs.h>
+#include <mach/iomap.h>
+#include <mach/clk.h>
+#include <mach/io.h>
+
+static int wdt_heartbeat = 30;
+
+#if defined(CONFIG_ARCH_TEGRA_3x_SOC)
+#define TIMER_PTV			0
+ #define TIMER_EN			(1 << 31)
+ #define TIMER_PERIODIC			(1 << 30)
+#define TIMER_PCR			0x4
+ #define TIMER_PCR_INTR			(1 << 30)
+#define WDT_CFG				(0)
+ #define WDT_CFG_TMR_SRC		(7 << 0) /* for TMR7. */
+ #define WDT_CFG_PERIOD			(1 << 4)
+ #define WDT_CFG_INT_EN			(1 << 12)
+ #define WDT_CFG_SYS_RST_EN		(1 << 14)
+ #define WDT_CFG_PMC2CAR_RST_EN		(1 << 15)
+#define WDT_CMD				(8)
+ #define WDT_CMD_START_COUNTER		(1 << 0)
+ #define WDT_CMD_DISABLE_COUNTER	(1 << 1)
+#define WDT_UNLOCK			(0xC)
+ #define WDT_UNLOCK_PATTERN		(0xC45A << 0)
+
+static void __iomem *wdt_timer  = IO_ADDRESS(TEGRA_TMR7_BASE);
+static void __iomem *wdt_source = IO_ADDRESS(TEGRA_WDT0_BASE);
+
+static void tegra_wdt_reset_enable(void)
+{
+	u32 val;
+
+	writel(TIMER_PCR_INTR, wdt_timer + TIMER_PCR);
+	val = (wdt_heartbeat * 1000000ul) / 4;
+	val |= (TIMER_EN | TIMER_PERIODIC);
+	writel(val, wdt_timer + TIMER_PTV);
+
+	val = WDT_CFG_TMR_SRC | WDT_CFG_PERIOD | /*WDT_CFG_INT_EN |*/
+		/*WDT_CFG_SYS_RST_EN |*/ WDT_CFG_PMC2CAR_RST_EN;
+	writel(val, wdt_source + WDT_CFG);
+	writel(WDT_CMD_START_COUNTER, wdt_source + WDT_CMD);
+	pr_info("%s: WDT Recovery Enabled\n", __func__);
+}
+
+static int tegra_wdt_reset_disable(void)
+{
+	writel(TIMER_PCR_INTR, wdt_timer + TIMER_PCR);
+	writel(WDT_UNLOCK_PATTERN, wdt_source + WDT_UNLOCK);
+	writel(WDT_CMD_DISABLE_COUNTER, wdt_source + WDT_CMD);
+
+	writel(0, wdt_timer + TIMER_PTV);
+	pr_info("%s: WDT Recovery Disabled\n", __func__);
+
+	return 0;
+}
+#elif defined(CONFIG_ARCH_TEGRA_2x_SOC)
+
+static void tegra_wdt_reset_enable(void)
+{
+}
+static int tegra_wdt_reset_disable(void)
+{
+	return 0;
+}
+#endif
+
+static int tegra_pm_notify(struct notifier_block *nb,
+			unsigned long event, void *nouse)
+{
+	switch (event) {
+	case PM_SUSPEND_PREPARE:
+		tegra_wdt_reset_enable();
+		break;
+	case PM_POST_SUSPEND:
+		tegra_wdt_reset_disable();
+		break;
+	}
+
+	return NOTIFY_OK;
+}
+
+static struct notifier_block tegra_wdt_notify = {
+	.notifier_call = tegra_pm_notify,
+};
+
+static struct syscore_ops tegra_wdt_syscore_ops = {
+	.suspend =	tegra_wdt_reset_disable,
+	.resume =	tegra_wdt_reset_enable,
+};
+
+void __init tegra_wdt_recovery_init(void)
+{
+#ifdef CONFIG_PM
+	/* Register PM notifier. */
+	register_pm_notifier(&tegra_wdt_notify);
+#endif
+	register_syscore_ops(&tegra_wdt_syscore_ops);
+}