soc: qcom: watchdog_v2: Add support to trigger watchdog bite on panic

In certain cases during a kernel panic,the interrupts on non-panicking
CPUs are disabled. Since CPU context cannot be collected by sending IPI
to those CPUs, we're limited to debug the problem. Forcing a watchdog
bite during kernel panic will ensure us getting the proper CPU context.
Hence adding support for the same.

Change-Id: Id06030d9bc46d94209da7f0ef8c47bfd3477baf6
Signed-off-by: Subbaraman Narayanamurthy <subbaram@codeaurora.org>
[abhimany: resolve trivial merge conflicts]
Signed-off-by: Abhimanyu Kapur <abhimany@codeaurora.org>

4 files changed, 44 insertions, 12 deletions

diff --git a/drivers/power/reset/msm-poweroff.c b/drivers/power/reset/msm-poweroff.c
index c7d8dd305312..2bcfb6c4e39a 100644
--- a/drivers/power/reset/msm-poweroff.c
+++ b/drivers/power/reset/msm-poweroff.c
@@ -31,6 +31,7 @@
 
 #include <soc/qcom/scm.h>
 #include <soc/qcom/restart.h>
+#include <soc/qcom/watchdog.h>
 
 #define EMERGENCY_DLOAD_MAGIC1    0x322A4F99
 #define EMERGENCY_DLOAD_MAGIC2    0xC67E4350
@@ -267,6 +268,14 @@ static void do_msm_restart(enum reboot_mode reboot_mode, const char *cmd)
 
 	msm_restart_prepare(cmd);
 
+	/*
+	 * Trigger a watchdog bite here and if this fails,
+	 * device will take the usual restart path.
+	 */
+
+	if (WDOG_BITE_ON_PANIC && in_panic)
+		msm_trigger_wdog_bite();
+
 	/* Needed to bypass debug image on some chips */
 	if (!is_scm_armv8())
 		ret = scm_call_atomic2(SCM_SVC_BOOT,
diff --git a/drivers/soc/qcom/Kconfig b/drivers/soc/qcom/Kconfig
index 12ce797383e7..e25a37e7ecd5 100644
--- a/drivers/soc/qcom/Kconfig
+++ b/drivers/soc/qcom/Kconfig
@@ -230,3 +230,11 @@ config TRACER_PKT
 	  Tracer Packet helps in profiling the performance of inter-
 	  processor communication protocols. The profiling information
 	  can be logged into the tracer packet itself.
+
+config QCOM_FORCE_WDOG_BITE_ON_PANIC
+	bool "QCOM force watchdog bite"
+	depends on QCOM_WATCHDOG_V2
+	help
+	  This forces a watchdog bite when the device restarts due to a
+	  kernel panic. On certain MSM SoCs, this provides us
+	  additional debugging information.
diff --git a/drivers/soc/qcom/watchdog_v2.c b/drivers/soc/qcom/watchdog_v2.c
index 6bef39edc003..6ea51140da28 100644
--- a/drivers/soc/qcom/watchdog_v2.c
+++ b/drivers/soc/qcom/watchdog_v2.c
@@ -28,6 +28,7 @@
 #include <linux/platform_device.h>
 #include <soc/qcom/scm.h>
 #include <soc/qcom/memory_dump.h>
+#include <soc/qcom/watchdog.h>
 
 #define MODULE_NAME "msm_watchdog"
 #define WDT0_ACCSCSSNBARK_INT 0
@@ -406,18 +407,7 @@ static irqreturn_t wdog_bark_handler(int irq, void *dev_id)
 		wdog_dd->last_pet, nanosec_rem / 1000);
 	if (wdog_dd->do_ipi_ping)
 		dump_cpu_alive_mask(wdog_dd);
-	printk(KERN_INFO "Causing a watchdog bite!");
-	__raw_writel(1, wdog_dd->base + WDT0_BITE_TIME);
-	mb();
-	__raw_writel(1, wdog_dd->base + WDT0_RST);
-	mb();
-	/* Delay to make sure bite occurs */
-	mdelay(1);
-	pr_err("Wdog - STS: 0x%x, CTL: 0x%x, BARK TIME: 0x%x, BITE TIME: 0x%x",
-		__raw_readl(wdog_dd->base + WDT0_STS),
-		__raw_readl(wdog_dd->base + WDT0_EN),
-		__raw_readl(wdog_dd->base + WDT0_BARK_TIME),
-		__raw_readl(wdog_dd->base + WDT0_BITE_TIME));
+	msm_trigger_wdog_bite();
 	panic("Failed to cause a watchdog bite! - Falling back to kernel panic!");
 	return IRQ_HANDLED;
 }
diff --git a/include/soc/qcom/watchdog.h b/include/soc/qcom/watchdog.h
new file mode 100644
index 000000000000..d82858f30a55
--- /dev/null
+++ b/include/soc/qcom/watchdog.h
@@ -0,0 +1,25 @@
+/* Copyright (c) 2014, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * 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.
+ *
+ */
+
+#ifndef _ASM_ARCH_MSM_WATCHDOG_H_
+#define _ASM_ARCH_MSM_WATCHDOG_H_
+
+#ifdef CONFIG_QCOM_FORCE_WDOG_BITE_ON_PANIC
+#define WDOG_BITE_ON_PANIC 1
+#else
+#define WDOG_BITE_ON_PANIC 0
+#endif
+
+void msm_trigger_wdog_bite(void);
+
+#endif