watchdog: Implement generic watchdog_reset() version

This patch tries to implement a generic watchdog_reset() function that
can be used by all boards that want to service the watchdog device in
U-Boot. This watchdog servicing is enabled via CONFIG_WATCHDOG.

Without this approach, new boards or platforms needed to implement a
board specific version of this functionality, mostly copy'ing the same
code over and over again into their board or platforms code base.

With this new generic function, the scattered other functions are now
removed to be replaced by the generic one. The new version also enables
the configuration of the watchdog timeout via the DT "timeout-sec"
property (if enabled via CONFIG_OF_CONTROL).

This patch also adds a new flag to the GD flags, to flag that the
watchdog is ready to use and adds the pointer to the watchdog device
to the GD. This enables us to remove the global "watchdog_dev"
variable, which was prone to cause problems because of its potentially
very early use in watchdog_reset(), even before the BSS is cleared.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Heiko Schocher <hs@denx.de>
Cc: Tom Rini <trini@konsulko.com>
Cc: Michal Simek <michal.simek@xilinx.com>
Cc: "Marek Behún" <marek.behun@nic.cz>
Cc: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
Cc: Maxim Sloyko <maxims@google.com>
Cc: Erik van Luijk <evanluijk@interact.nl>
Cc: Ryder Lee <ryder.lee@mediatek.com>
Cc: Weijie Gao <weijie.gao@mediatek.com>
Cc: Simon Glass <sjg@chromium.org>
Cc: "Álvaro Fernández Rojas" <noltari@gmail.com>
Cc: Philippe Reynes <philippe.reynes@softathome.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Michal Simek <michal.simek@xilinx.com>
Tested-by: Michal Simek <michal.simek@xilinx.com> (on zcu100)

3 files changed, 45 insertions, 5 deletions

diff --git a/include/asm-generic/global_data.h b/include/asm-generic/global_data.h
index 65ee3e5d5a..02a3ed6838 100644
--- a/include/asm-generic/global_data.h
+++ b/include/asm-generic/global_data.h
@@ -137,6 +137,9 @@ typedef struct global_data {
 #if defined(CONFIG_TRANSLATION_OFFSET)
 	fdt_addr_t translation_offset;	/* optional translation offset */
 #endif
+#if defined(CONFIG_WDT)
+	struct udevice *watchdog_dev;
+#endif
 } gd_t;
 #endif
 
@@ -165,5 +168,6 @@ typedef struct global_data {
 #define GD_FLG_ENV_DEFAULT	0x02000 /* Default variable flag	   */
 #define GD_FLG_SPL_EARLY_INIT	0x04000 /* Early SPL init is done	   */
 #define GD_FLG_LOG_READY	0x08000 /* Log system is ready for use	   */
+#define GD_FLG_WDT_READY	0x10000 /* Watchdog is ready for use	   */
 
 #endif /* __ASM_GENERIC_GBL_DATA_H */
diff --git a/include/configs/turris_omnia.h b/include/configs/turris_omnia.h
index c7805cf36b..0e65a12345 100644
--- a/include/configs/turris_omnia.h
+++ b/include/configs/turris_omnia.h
@@ -29,11 +29,6 @@
 #define CONFIG_SPL_I2C_MUX
 #define CONFIG_SYS_I2C_MVTWSI
 
-/* Watchdog support */
-#if !defined(CONFIG_SPL_BUILD) && defined(CONFIG_WDT_ORION)
-# define CONFIG_WATCHDOG
-#endif
-
 /*
  * SDIO/MMC Card Configuration
  */
diff --git a/include/wdt.h b/include/wdt.h
index e9a7c5355a..aa77d3e9b4 100644
--- a/include/wdt.h
+++ b/include/wdt.h
@@ -6,6 +6,9 @@
 #ifndef _WDT_H_
 #define _WDT_H_
 
+#include <dm.h>
+#include <dm/read.h>
+
 /*
  * Implement a simple watchdog uclass. Watchdog is basically a timer that
  * is used to detect or recover from malfunction. During normal operation
@@ -103,4 +106,42 @@ struct wdt_ops {
 	int (*expire_now)(struct udevice *dev, ulong flags);
 };
 
+#if defined(CONFIG_WDT)
+#ifndef CONFIG_WATCHDOG_TIMEOUT_MSECS
+#define CONFIG_WATCHDOG_TIMEOUT_MSECS	(60 * 1000)
+#endif
+#define WATCHDOG_TIMEOUT_SECS	(CONFIG_WATCHDOG_TIMEOUT_MSECS / 1000)
+
+static inline int initr_watchdog(void)
+{
+	u32 timeout = WATCHDOG_TIMEOUT_SECS;
+
+	/*
+	 * Init watchdog: This will call the probe function of the
+	 * watchdog driver, enabling the use of the device
+	 */
+	if (uclass_get_device_by_seq(UCLASS_WDT, 0,
+				     (struct udevice **)&gd->watchdog_dev)) {
+		debug("WDT:   Not found by seq!\n");
+		if (uclass_get_device(UCLASS_WDT, 0,
+				      (struct udevice **)&gd->watchdog_dev)) {
+			printf("WDT:   Not found!\n");
+			return 0;
+		}
+	}
+
+	if (CONFIG_IS_ENABLED(OF_CONTROL)) {
+		timeout = dev_read_u32_default(gd->watchdog_dev, "timeout-sec",
+					       WATCHDOG_TIMEOUT_SECS);
+	}
+
+	wdt_start(gd->watchdog_dev, timeout * 1000, 0);
+	gd->flags |= GD_FLG_WDT_READY;
+	printf("WDT:   Started with%s servicing (%ds timeout)\n",
+	       IS_ENABLED(CONFIG_WATCHDOG) ? "" : "out", timeout);
+
+	return 0;
+}
+#endif
+
 #endif  /* _WDT_H_ */