[PATCH 2/7] watchdog: add at91sam9 watchdog support
Jean-Christophe PLAGNIOL-VILLARD
plagnioj at jcrosoft.com
Fri Nov 16 12:55:40 EST 2012
with keep alive support
Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj at jcrosoft.com>
---
drivers/watchdog/Kconfig | 7 +++
drivers/watchdog/Makefile | 1 +
drivers/watchdog/at91sam9_wdt.c | 131 +++++++++++++++++++++++++++++++++++++++
drivers/watchdog/at91sam9_wdt.h | 38 ++++++++++++
4 files changed, 177 insertions(+)
create mode 100644 drivers/watchdog/at91sam9_wdt.c
create mode 100644 drivers/watchdog/at91sam9_wdt.h
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 21480a1..5bd1083 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -7,6 +7,13 @@ menuconfig WATCHDOG
if WATCHDOG
+config WATCHDOG_AT91SAM9X
+ tristate "AT91SAM9X / AT91CAP9 watchdog"
+ depends on ARCH_AT91
+ help
+ Watchdog timer embedded into AT91SAM9X and AT91CAP9 chips. This will
+ reboot your system when the timeout is reached.
+
config WATCHDOG_MXS28
bool "i.MX28"
depends on ARCH_IMX28
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index b29103b..4e863a5 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -1,2 +1,3 @@
obj-$(CONFIG_WATCHDOG) += wd_core.o
+obj-$(CONFIG_WATCHDOG_AT91SAM9X) += at91sam9_wdt.o
obj-$(CONFIG_WATCHDOG_MXS28) += im28wd.o
diff --git a/drivers/watchdog/at91sam9_wdt.c b/drivers/watchdog/at91sam9_wdt.c
new file mode 100644
index 0000000..203d83a
--- /dev/null
+++ b/drivers/watchdog/at91sam9_wdt.c
@@ -0,0 +1,131 @@
+/*
+ * (c) 2012 Juergen Beisert <kernel at pengutronix.de>
+ *
+ * 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; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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.
+ *
+ * Note: this driver works for the i.MX28 SoC. It might work for the
+ * i.MX23 Soc as well, but is not tested yet.
+ */
+
+#include <common.h>
+#include <init.h>
+#include <io.h>
+#include <errno.h>
+#include <malloc.h>
+#include <watchdog.h>
+
+#include "at91sam9_wdt.h"
+
+struct at91sam9_wdt {
+ struct watchdog wdt;
+ void __iomem *base;
+};
+
+#define to_at91sam9_wdt(h) container_of(h, struct at91sam9_wdt, wdt)
+
+#define wdt_read(at91wdt, field) \
+ __raw_readl(at91wdt->base + field)
+#define wdt_write(at91wdt, field, val) \
+ __raw_writel((val), at91wdt->base + field)
+
+static void at91sam9_wdt_keep_alive(struct watchdog *wdt)
+{
+ struct at91sam9_wdt *at91wdt = to_at91sam9_wdt(wdt);
+
+ wdt_write(at91wdt, AT91_WDT_CR, AT91_WDT_KEY | AT91_WDT_WDRSTT);
+}
+
+static int at91sam9_wdt_settimeout(struct watchdog *wdt, unsigned int timeout)
+{
+ struct at91sam9_wdt *at91wdt = to_at91sam9_wdt(wdt);
+ unsigned int reg;
+ unsigned int mr;
+
+ /* Check if disabled */
+ mr = wdt_read(at91wdt, AT91_WDT_MR);
+ if (mr & AT91_WDT_WDDIS) {
+ pr_err("sorry, watchdog is disabled\n");
+ return -EIO;
+ }
+
+ if (!timeout) {
+ wdt_write(at91wdt, AT91_WDT_MR, AT91_WDT_WDDIS);
+ return 0;
+ }
+
+ /*
+ * All counting occurs at SLOW_CLOCK / 128 = 256 Hz
+ *
+ * Since WDV is a 12-bit counter, the maximum period is
+ * 4096 / 256 = 16 seconds.
+ */
+ reg = AT91_WDT_WDRSTEN /* causes watchdog reset */
+ /* | AT91_WDT_WDRPROC causes processor reset only */
+ | AT91_WDT_WDDBGHLT /* disabled in debug mode */
+ | AT91_WDT_WDD /* restart at any time */
+ | (timeout & AT91_WDT_WDV); /* timer value */
+ wdt_write(at91wdt, AT91_WDT_MR, reg);
+
+ return 0;
+}
+
+static int at91sam9_wdt_probe(struct device_d *dev)
+{
+ struct at91sam9_wdt *priv;
+ struct watchdog *wdt;
+ int ret;
+ unsigned int mr;
+
+ priv = xzalloc(sizeof(struct at91sam9_wdt));
+ priv->base = dev_request_mem_region(dev, 0);
+ wdt = &priv->wdt;
+
+ wdt->set_timeout = at91sam9_wdt_settimeout;
+ wdt->keep_alive = at91sam9_wdt_keep_alive;
+
+ /* Check if disabled */
+ mr = wdt_read(priv, AT91_WDT_MR);
+ if (mr & AT91_WDT_WDDIS) {
+ dev_err(dev, "sorry, watchdog is disabled\n");
+ ret = -EIO;
+ goto err;
+ }
+
+ ret = watchdog_register(wdt);
+ if (ret != 0)
+ goto err;
+
+ dev->priv = priv;
+ return 0;
+
+err:
+ free(priv);
+ return ret;
+}
+
+static void at91sam9_wdt_remove(struct device_d *dev)
+{
+ struct at91sam9_wdt *priv= dev->priv;
+ watchdog_deregister(&priv->wdt);
+ free(priv);
+}
+
+static struct driver_d at91sam9_wdt_driver = {
+ .name = "at91sam9_wdt",
+ .probe = at91sam9_wdt_probe,
+ .remove = at91sam9_wdt_remove,
+};
+
+static int at91sam9_wdt_init(void)
+{
+ return platform_driver_register(&at91sam9_wdt_driver);
+}
+coredevice_initcall(at91sam9_wdt_init);
diff --git a/drivers/watchdog/at91sam9_wdt.h b/drivers/watchdog/at91sam9_wdt.h
new file mode 100644
index 0000000..2b68c1a
--- /dev/null
+++ b/drivers/watchdog/at91sam9_wdt.h
@@ -0,0 +1,38 @@
+/*
+ * drivers/watchdog/at91sam9_wdt.h
+ *
+ * Copyright (C) 2007 Andrew Victor
+ * Copyright (C) 2007 Atmel Corporation.
+ *
+ * Watchdog Timer (WDT) - System peripherals regsters.
+ * Based on AT91SAM9261 datasheet revision D.
+ *
+ * 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; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#ifndef AT91_WDT_H
+#define AT91_WDT_H
+
+#define AT91_WDT_CR 0x00 /* Watchdog Control Register */
+#define AT91_WDT_WDRSTT (1 << 0) /* Restart */
+#define AT91_WDT_KEY (0xa5 << 24) /* KEY Password */
+
+#define AT91_WDT_MR 0x04 /* Watchdog Mode Register */
+#define AT91_WDT_WDV (0xfff << 0) /* Counter Value */
+#define AT91_WDT_WDFIEN (1 << 12) /* Fault Interrupt Enable */
+#define AT91_WDT_WDRSTEN (1 << 13) /* Reset Processor */
+#define AT91_WDT_WDRPROC (1 << 14) /* Timer Restart */
+#define AT91_WDT_WDDIS (1 << 15) /* Watchdog Disable */
+#define AT91_WDT_WDD (0xfff << 16) /* Delta Value */
+#define AT91_WDT_WDDBGHLT (1 << 28) /* Debug Halt */
+#define AT91_WDT_WDIDLEHLT (1 << 29) /* Idle Halt */
+
+#define AT91_WDT_SR 0x08 /* Watchdog Status Register */
+#define AT91_WDT_WDUNF (1 << 0) /* Watchdog Underflow */
+#define AT91_WDT_WDERR (1 << 1) /* Watchdog Error */
+
+
+#endif
--
1.7.10.4
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