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>

5 files changed, 160 insertions, 0 deletions

diff --git a/arch/arm/mach-tegra/Kconfig b/arch/arm/mach-tegra/Kconfig
index bf5f4dd04862..7306df5d3672 100644
--- a/arch/arm/mach-tegra/Kconfig
+++ b/arch/arm/mach-tegra/Kconfig
@@ -448,5 +448,12 @@ config TEGRA_PLLM_RESTRICTED
 	  capable of dividing maximum PLLM frequency at minimum voltage. When
 	  disabled, PLLM is used as a clock source with no restrictions (which
 	  may effectively increase lower limit for core voltage).
+
+config TEGRA_WDT_RECOVERY
+	bool "Enable suspend/resume watchdog recovery mechanism"
+	default n
+	help
+	  Enables watchdog recovery mechanism to protect against
+	  suspend/resume hangs.
 endif
 
diff --git a/arch/arm/mach-tegra/Makefile b/arch/arm/mach-tegra/Makefile
index 45860e27a3e0..a4d1b217c163 100644
--- a/arch/arm/mach-tegra/Makefile
+++ b/arch/arm/mach-tegra/Makefile
@@ -22,6 +22,7 @@ obj-y                                   += devices.o
 obj-y                                   += delay.o
 obj-y                                   += powergate.o
 obj-y                                   += pm.o
+obj-$(CONFIG_TEGRA_WDT_RECOVERY)        += wdt-recovery.o
 obj-$(CONFIG_PM_SLEEP)                  += pm-irq.o
 obj-y                                   += gic.o
 obj-y                                   += sleep.o
diff --git a/arch/arm/mach-tegra/board-cardhu.c b/arch/arm/mach-tegra/board-cardhu.c
index b571e799749a..81129d1a2762 100644
--- a/arch/arm/mach-tegra/board-cardhu.c
+++ b/arch/arm/mach-tegra/board-cardhu.c
@@ -64,6 +64,7 @@
 #include "fuse.h"
 #include "pm.h"
 #include "baseband-xmm-power.h"
+#include "wdt-recovery.h"
 
 /* All units are in millicelsius */
 static struct tegra_thermal_data thermal_data = {
@@ -997,6 +998,9 @@ static void __init tegra_cardhu_init(void)
 	tegra_release_bootloader_fb();
 	cardhu_nfc_init();
 	cardhu_pci_init();
+#ifdef CONFIG_TEGRA_WDT_RECOVERY
+	tegra_wdt_recovery_init();
+#endif
 }
 
 static void __init cardhu_ramconsole_reserve(unsigned long size)
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);
+}
diff --git a/arch/arm/mach-tegra/wdt-recovery.h b/arch/arm/mach-tegra/wdt-recovery.h
new file mode 100644
index 000000000000..e26c1d038574
--- /dev/null
+++ b/arch/arm/mach-tegra/wdt-recovery.h
@@ -0,0 +1,17 @@
+/*
+ * arch/arm/mach-tegra/wdt-recovery.h
+ *
+ * Copyright (C) 2011 NVIDIA Corporation.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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.
+ *
+ */
+
+void __init tegra_wdt_recovery_init(void);