[PATCH 3/6] ARM: SAMSUNG: Add watchdog reset driver

Tomasz Figa
2013-05-18T22:37:04Z

This patch adds a watchdog reset driver that can be used on Samsung SoCs
that do not provide dedicated reset method. It replaces the legacy
helper function that relies on static IO mapping.

Signed-off-by: Tomasz Figa <tomasz.figa@gmail.com>
---
arch/arm/plat-samsung/Kconfig | 6 ++
arch/arm/plat-samsung/Makefile | 1 +
.../arm/plat-samsung/include/plat/watchdog-reset.h | 9 ++
arch/arm/plat-samsung/watchdog-reset.c | 97 ++++++++++++++++++++++
4 files changed, 113 insertions(+)
create mode 100644 arch/arm/plat-samsung/watchdog-reset.c

diff --git a/arch/arm/plat-samsung/Kconfig b/arch/arm/plat-samsung/Kconfig
index f8ed2de..ec68155 100644
--- a/arch/arm/plat-samsung/Kconfig
+++ b/arch/arm/plat-samsung/Kconfig
@@ -475,6 +475,12 @@ config SAMSUNG_WAKEMASK
and above. This code allows a set of interrupt to wakeup-mask
mappings. See <plat/wakeup-mask.h>

+config SAMSUNG_WDT_RESET
+ bool
+ help
+ Compile support for system restart by triggering watchdog reset.
+ Used on SoCs that do not provide dedicated reset control.
+
config S5P_PM
bool
help
diff --git a/arch/arm/plat-samsung/Makefile b/arch/arm/plat-samsung/Makefile
index a23c460..03cea14 100644
--- a/arch/arm/plat-samsung/Makefile
+++ b/arch/arm/plat-samsung/Makefile
@@ -56,6 +56,7 @@ obj-$(CONFIG_PM) += pm-gpio.o
obj-$(CONFIG_SAMSUNG_PM_CHECK) += pm-check.o

obj-$(CONFIG_SAMSUNG_WAKEMASK) += wakeup-mask.o
+obj-$(CONFIG_SAMSUNG_WDT_RESET) += watchdog-reset.o

obj-$(CONFIG_S5P_PM) += s5p-pm.o s5p-irq-pm.o
obj-$(CONFIG_S5P_SLEEP) += s5p-sleep.o
diff --git a/arch/arm/plat-samsung/include/plat/watchdog-reset.h b/arch/arm/plat-samsung/include/plat/watchdog-reset.h
index bc4db9b..4def1b2 100644
--- a/arch/arm/plat-samsung/include/plat/watchdog-reset.h
+++ b/arch/arm/plat-samsung/include/plat/watchdog-reset.h
@@ -10,6 +10,9 @@
* published by the Free Software Foundation.
*/

+#ifndef __PLAT_WATCHDOG_RESET_H
+#define __PLAT_WATCHDOG_RESET_H
+
#include <plat/clock.h>
#include <plat/regs-watchdog.h>
#include <mach/map.h>
@@ -44,3 +47,9 @@ static inline void arch_wdt_reset(void)
/* delay to allow the serial port to show the message */
mdelay(50);
}
+
+extern void samsung_wdt_reset(void);
+extern void samsung_wdt_reset_of_init(void);
+extern void samsung_wdt_reset_init(void __iomem *base);
+
+#endif /* __PLAT_WATCHDOG_RESET_H */
diff --git a/arch/arm/plat-samsung/watchdog-reset.c b/arch/arm/plat-samsung/watchdog-reset.c
new file mode 100644
index 0000000..2ecb50be
--- /dev/null
+++ b/arch/arm/plat-samsung/watchdog-reset.c
@@ -0,0 +1,97 @@
+/* arch/arm/plat-samsung/watchdog-reset.c
+ *
+ * Copyright (c) 2008 Simtec Electronics
+ * Ben Dooks <ben@simtec.co.uk>
+ *
+ * Coyright (c) 2013 Tomasz Figa <tomasz.figa@gmail.com>
+ *
+ * Watchdog reset support for Samsung SoCs.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+*/
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/delay.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+
+#define S3C2410_WTCON 0x00
+#define S3C2410_WTDAT 0x04
+#define S3C2410_WTCNT 0x08
+
+#define S3C2410_WTCON_ENABLE (1 << 5)
+#define S3C2410_WTCON_DIV16 (0 << 3)
+#define S3C2410_WTCON_RSTEN (1 << 0)
+#define S3C2410_WTCON_PRESCALE(x) ((x) << 8)
+
+static void __iomem *wdt_base;
+static struct clk *wdt_clock;
+
+void samsung_wdt_reset(void)
+{
+ if (!wdt_base) {
+ pr_err("%s: wdt reset not initialized\n", __func__);
+ /* delay to allow the serial port to show the message */
+ mdelay(50);
+ return;
+ }
+
+ if (!IS_ERR(wdt_clock))
+ clk_prepare_enable(wdt_clock);
+
+ /* disable watchdog, to be safe */
+ __raw_writel(0, wdt_base + S3C2410_WTCON);
+
+ /* put initial values into count and data */
+ __raw_writel(0x80, wdt_base + S3C2410_WTCNT);
+ __raw_writel(0x80, wdt_base + S3C2410_WTDAT);
+
+ /* set the watchdog to go and reset... */
+ __raw_writel(S3C2410_WTCON_ENABLE | S3C2410_WTCON_DIV16 |
+ S3C2410_WTCON_RSTEN | S3C2410_WTCON_PRESCALE(0x20),
+ wdt_base + S3C2410_WTCON);
+
+ /* wait for reset to assert... */
+ mdelay(500);
+
+ pr_err("Watchdog reset failed to assert reset\n");
+
+ /* delay to allow the serial port to show the message */
+ mdelay(50);
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id s3c2410_wdt_match[] = {
+ { .compatible = "samsung,s3c2410-wdt" },
+ {},
+};
+
+void __init samsung_wdt_reset_of_init(void)
+{
+ struct device_node *np;
+
+ np = of_find_matching_node(NULL, s3c2410_wdt_match);
+ if (!np) {
+ pr_err("%s: failed to find watchdog node\n", __func__);
+ return;
+ }
+
+ wdt_base = of_iomap(np, 0);
+ if (!wdt_base) {
+ pr_err("%s: failed to map watchdog registers\n", __func__);
+ return;
+ }
+
+ wdt_clock = of_clk_get(np, 0);
+}
+#endif
+
+void __init samsung_wdt_reset_init(void __iomem *base)
+{
+ wdt_base = base;
+ wdt_clock = clk_get(NULL, "watchdog");
+}
--
1.8.2.1