watchdog: sirf: add watchdog driver of CSR SiRFprimaII and SiRFatlasVI

On CSR SiRFprimaII and SiRFatlasVI, the 6th timer can act as a watchdog
timer when the Watchdog mode is enabled.

watchdog occur when TIMER watchdog counter matches the value software
pre-set, when this event occurs, the effect is the same as the system
software reset.

Signed-off-by: Xianglong Du <Xianglong.Du@csr.com>
Signed-off-by: Barry Song <Baohua.Song@csr.com>
Cc: Romain Izard <romain.izard.pro@gmail.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

3 files changed, 234 insertions, 0 deletions

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 4327b48a35a3..74f29a2fc51c 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -402,6 +402,15 @@ config MOXART_WDT
           To compile this driver as a module, choose M here: the
           module will be called moxart_wdt.
 
+config SIRFSOC_WATCHDOG
+        tristate "SiRFSOC watchdog"
+        depends on ARCH_SIRF
+        select WATCHDOG_CORE
+        default y
+        help
+          Support for CSR SiRFprimaII and SiRFatlasVI watchdog. When
+          the watchdog triggers the system will be reset.
+
 # AVR32 Architecture
 
 config AT32AP700X_WDT
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 89fd3288cd7b..91bd95a64baf 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -56,6 +56,7 @@ obj-$(CONFIG_UX500_WATCHDOG) += ux500_wdt.o
 obj-$(CONFIG_RETU_WATCHDOG) += retu_wdt.o
 obj-$(CONFIG_BCM2835_WDT) += bcm2835_wdt.o
 obj-$(CONFIG_MOXART_WDT) += moxart_wdt.o
+obj-$(CONFIG_SIRFSOC_WATCHDOG) += sirfsoc_wdt.o
 
 # AVR32 Architecture
 obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o
diff --git a/drivers/watchdog/sirfsoc_wdt.c b/drivers/watchdog/sirfsoc_wdt.c
new file mode 100644
index 000000000000..3b8d7397e001
--- /dev/null
+++ b/drivers/watchdog/sirfsoc_wdt.c
@@ -0,0 +1,224 @@
+/*
+ * Watchdog driver for CSR SiRFprimaII and SiRFatlasVI
+ *
+ * Copyright (c) 2013 Cambridge Silicon Radio Limited, a CSR plc group company.
+ *
+ * Licensed under GPLv2 or later.
+ */
+
+#include <linux/module.h>
+#include <linux/watchdog.h>
+#include <linux/platform_device.h>
+#include <linux/moduleparam.h>
+#include <linux/of.h>
+#include <linux/io.h>
+#include <linux/uaccess.h>
+
+#define SIRFSOC_TIMER_COUNTER_LO        0x0000
+#define SIRFSOC_TIMER_MATCH_0           0x0008
+#define SIRFSOC_TIMER_INT_EN            0x0024
+#define SIRFSOC_TIMER_WATCHDOG_EN       0x0028
+#define SIRFSOC_TIMER_LATCH             0x0030
+#define SIRFSOC_TIMER_LATCHED_LO        0x0034
+
+#define SIRFSOC_TIMER_WDT_INDEX         5
+
+#define SIRFSOC_WDT_MIN_TIMEOUT         30              /* 30 secs */
+#define SIRFSOC_WDT_MAX_TIMEOUT         (10 * 60)       /* 10 mins */
+#define SIRFSOC_WDT_DEFAULT_TIMEOUT     30              /* 30 secs */
+
+static unsigned int timeout = SIRFSOC_WDT_DEFAULT_TIMEOUT;
+static bool nowayout = WATCHDOG_NOWAYOUT;
+
+module_param(timeout, uint, 0);
+module_param(nowayout, bool, 0);
+
+MODULE_PARM_DESC(timeout, "Default watchdog timeout (in seconds)");
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
+                        __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+static unsigned int sirfsoc_wdt_gettimeleft(struct watchdog_device *wdd)
+{
+        u32 counter, match;
+        void __iomem *wdt_base;
+        int time_left;
+
+        wdt_base = watchdog_get_drvdata(wdd);
+        counter = readl(wdt_base + SIRFSOC_TIMER_COUNTER_LO);
+        match = readl(wdt_base +
+                SIRFSOC_TIMER_MATCH_0 + (SIRFSOC_TIMER_WDT_INDEX << 2));
+
+        time_left = match - counter;
+
+        return time_left / CLOCK_TICK_RATE;
+}
+
+static int sirfsoc_wdt_updatetimeout(struct watchdog_device *wdd)
+{
+        u32 counter, timeout_ticks;
+        void __iomem *wdt_base;
+
+        timeout_ticks = wdd->timeout * CLOCK_TICK_RATE;
+        wdt_base = watchdog_get_drvdata(wdd);
+
+        /* Enable the latch before reading the LATCH_LO register */
+        writel(1, wdt_base + SIRFSOC_TIMER_LATCH);
+
+        /* Set the TO value */
+        counter = readl(wdt_base + SIRFSOC_TIMER_LATCHED_LO);
+
+        counter += timeout_ticks;
+
+        writel(counter, wdt_base +
+                SIRFSOC_TIMER_MATCH_0 + (SIRFSOC_TIMER_WDT_INDEX << 2));
+
+        return 0;
+}
+
+static int sirfsoc_wdt_enable(struct watchdog_device *wdd)
+{
+        void __iomem *wdt_base = watchdog_get_drvdata(wdd);
+        sirfsoc_wdt_updatetimeout(wdd);
+
+        /*
+         * NOTE: If interrupt is not enabled
+         * then WD-Reset doesn't get generated at all.
+         */
+        writel(readl(wdt_base + SIRFSOC_TIMER_INT_EN)
+                | (1 << SIRFSOC_TIMER_WDT_INDEX),
+                wdt_base + SIRFSOC_TIMER_INT_EN);
+        writel(1, wdt_base + SIRFSOC_TIMER_WATCHDOG_EN);
+
+        return 0;
+}
+
+static int sirfsoc_wdt_disable(struct watchdog_device *wdd)
+{
+        void __iomem *wdt_base = watchdog_get_drvdata(wdd);
+
+        writel(0, wdt_base + SIRFSOC_TIMER_WATCHDOG_EN);
+        writel(readl(wdt_base + SIRFSOC_TIMER_INT_EN)
+                & (~(1 << SIRFSOC_TIMER_WDT_INDEX)),
+                wdt_base + SIRFSOC_TIMER_INT_EN);
+
+        return 0;
+}
+
+static int sirfsoc_wdt_settimeout(struct watchdog_device *wdd, unsigned int to)
+{
+        wdd->timeout = to;
+        sirfsoc_wdt_updatetimeout(wdd);
+
+        return 0;
+}
+
+#define OPTIONS (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE)
+
+static const struct watchdog_info sirfsoc_wdt_ident = {
+        .options          =     OPTIONS,
+        .firmware_version =     0,
+        .identity         =     "SiRFSOC Watchdog",
+};
+
+static struct watchdog_ops sirfsoc_wdt_ops = {
+        .owner = THIS_MODULE,
+        .start = sirfsoc_wdt_enable,
+        .stop = sirfsoc_wdt_disable,
+        .get_timeleft = sirfsoc_wdt_gettimeleft,
+        .ping = sirfsoc_wdt_updatetimeout,
+        .set_timeout = sirfsoc_wdt_settimeout,
+};
+
+static struct watchdog_device sirfsoc_wdd = {
+        .info = &sirfsoc_wdt_ident,
+        .ops = &sirfsoc_wdt_ops,
+        .timeout = SIRFSOC_WDT_DEFAULT_TIMEOUT,
+        .min_timeout = SIRFSOC_WDT_MIN_TIMEOUT,
+        .max_timeout = SIRFSOC_WDT_MAX_TIMEOUT,
+};
+
+static int sirfsoc_wdt_probe(struct platform_device *pdev)
+{
+        struct resource *res;
+        int ret;
+        void __iomem *base;
+
+        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        base = devm_ioremap_resource(&pdev->dev, res);
+        if (IS_ERR(base))
+                return PTR_ERR(base);
+
+        watchdog_set_drvdata(&sirfsoc_wdd, base);
+
+        watchdog_init_timeout(&sirfsoc_wdd, timeout, &pdev->dev);
+        watchdog_set_nowayout(&sirfsoc_wdd, nowayout);
+
+        ret = watchdog_register_device(&sirfsoc_wdd);
+        if (ret)
+                return ret;
+
+        platform_set_drvdata(pdev, &sirfsoc_wdd);
+
+        return 0;
+}
+
+static void sirfsoc_wdt_shutdown(struct platform_device *pdev)
+{
+        struct watchdog_device *wdd = platform_get_drvdata(pdev);
+
+        sirfsoc_wdt_disable(wdd);
+}
+
+static int sirfsoc_wdt_remove(struct platform_device *pdev)
+{
+        sirfsoc_wdt_shutdown(pdev);
+        return 0;
+}
+
+#ifdef  CONFIG_PM_SLEEP
+static int sirfsoc_wdt_suspend(struct device *dev)
+{
+        return 0;
+}
+
+static int sirfsoc_wdt_resume(struct device *dev)
+{
+        struct watchdog_device *wdd = dev_get_drvdata(dev);
+
+        /*
+         * NOTE: Since timer controller registers settings are saved
+         * and restored back by the timer-prima2.c, so we need not
+         * update WD settings except refreshing timeout.
+         */
+        sirfsoc_wdt_updatetimeout(wdd);
+
+        return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(sirfsoc_wdt_pm_ops,
+                sirfsoc_wdt_suspend, sirfsoc_wdt_resume);
+
+static const struct of_device_id sirfsoc_wdt_of_match[] = {
+        { .compatible = "sirf,prima2-tick"},
+        {},
+};
+MODULE_DEVICE_TABLE(of, sirfsoc_wdt_of_match);
+
+static struct platform_driver sirfsoc_wdt_driver = {
+        .driver = {
+                .name = "sirfsoc-wdt",
+                .owner = THIS_MODULE,
+                .pm = &sirfsoc_wdt_pm_ops,
+                .of_match_table = of_match_ptr(sirfsoc_wdt_of_match),
+        },
+        .probe = sirfsoc_wdt_probe,
+        .remove = sirfsoc_wdt_remove,
+        .shutdown = sirfsoc_wdt_shutdown,
+};
+module_platform_driver(sirfsoc_wdt_driver);
+
+MODULE_DESCRIPTION("SiRF SoC watchdog driver");
+MODULE_AUTHOR("Xianglong Du <Xianglong.Du@csr.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:sirfsoc-wdt");