--- /dev/null
+/*
+ * Driver for Atmel SAMA5D4 Watchdog Timer
+ *
+ * Copyright (C) 2015 Atmel Corporation
+ *
+ * Licensed under GPLv2.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/platform_device.h>
+#include <linux/reboot.h>
+#include <linux/watchdog.h>
+
+#include "at91sam9_wdt.h"
+
+/* minimum and maximum watchdog timeout, in seconds */
+#define MIN_WDT_TIMEOUT 1
+#define MAX_WDT_TIMEOUT 16
+#define WDT_DEFAULT_TIMEOUT MAX_WDT_TIMEOUT
+
+#define WDT_SEC2TICKS(s) ((s) ? (((s) << 8) - 1) : 0)
+
+struct sama5d4_wdt {
+ struct watchdog_device wdd;
+ void __iomem *reg_base;
+ u32 config;
+};
+
+static int wdt_timeout = WDT_DEFAULT_TIMEOUT;
+static bool nowayout = WATCHDOG_NOWAYOUT;
+
+module_param(wdt_timeout, int, 0);
+MODULE_PARM_DESC(wdt_timeout,
+ "Watchdog timeout in seconds. (default = "
+ __MODULE_STRING(WDT_DEFAULT_TIMEOUT) ")");
+
+module_param(nowayout, bool, 0);
+MODULE_PARM_DESC(nowayout,
+ "Watchdog cannot be stopped once started (default="
+ __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+#define wdt_read(wdt, field) \
+ readl_relaxed((wdt)->reg_base + (field))
+
+#define wdt_write(wtd, field, val) \
+ writel_relaxed((val), (wdt)->reg_base + (field))
+
+static int sama5d4_wdt_start(struct watchdog_device *wdd)
+{
+ struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd);
+ u32 reg;
+
+ reg = wdt_read(wdt, AT91_WDT_MR);
+ reg &= ~AT91_WDT_WDDIS;
+ wdt_write(wdt, AT91_WDT_MR, reg);
+
+ return 0;
+}
+
+static int sama5d4_wdt_stop(struct watchdog_device *wdd)
+{
+ struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd);
+ u32 reg;
+
+ reg = wdt_read(wdt, AT91_WDT_MR);
+ reg |= AT91_WDT_WDDIS;
+ wdt_write(wdt, AT91_WDT_MR, reg);
+
+ return 0;
+}
+
+static int sama5d4_wdt_ping(struct watchdog_device *wdd)
+{
+ struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd);
+
+ wdt_write(wdt, AT91_WDT_CR, AT91_WDT_KEY | AT91_WDT_WDRSTT);
+
+ return 0;
+}
+
+static int sama5d4_wdt_set_timeout(struct watchdog_device *wdd,
+ unsigned int timeout)
+{
+ struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd);
+ u32 value = WDT_SEC2TICKS(timeout);
+ u32 reg;
+
+ reg = wdt_read(wdt, AT91_WDT_MR);
+ reg &= ~AT91_WDT_WDV;
+ reg &= ~AT91_WDT_WDD;
+ reg |= AT91_WDT_SET_WDV(value);
+ reg |= AT91_WDT_SET_WDD(value);
+ wdt_write(wdt, AT91_WDT_MR, reg);
+
+ wdd->timeout = timeout;
+
+ return 0;
+}
+
+static const struct watchdog_info sama5d4_wdt_info = {
+ .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
+ .identity = "Atmel SAMA5D4 Watchdog",
+};
+
+static struct watchdog_ops sama5d4_wdt_ops = {
+ .owner = THIS_MODULE,
+ .start = sama5d4_wdt_start,
+ .stop = sama5d4_wdt_stop,
+ .ping = sama5d4_wdt_ping,
+ .set_timeout = sama5d4_wdt_set_timeout,
+};
+
+static irqreturn_t sama5d4_wdt_irq_handler(int irq, void *dev_id)
+{
+ struct sama5d4_wdt *wdt = platform_get_drvdata(dev_id);
+
+ if (wdt_read(wdt, AT91_WDT_SR)) {
+ pr_crit("Atmel Watchdog Software Reset\n");
+ emergency_restart();
+ pr_crit("Reboot didn't succeed\n");
+ }
+
+ return IRQ_HANDLED;
+}
+
+static int of_sama5d4_wdt_init(struct device_node *np, struct sama5d4_wdt *wdt)
+{
+ const char *tmp;
+
+ wdt->config = AT91_WDT_WDDIS;
+
+ if (!of_property_read_string(np, "atmel,watchdog-type", &tmp) &&
+ !strcmp(tmp, "software"))
+ wdt->config |= AT91_WDT_WDFIEN;
+ else
+ wdt->config |= AT91_WDT_WDRSTEN;
+
+ if (of_property_read_bool(np, "atmel,idle-halt"))
+ wdt->config |= AT91_WDT_WDIDLEHLT;
+
+ if (of_property_read_bool(np, "atmel,dbg-halt"))
+ wdt->config |= AT91_WDT_WDDBGHLT;
+
+ return 0;
+}
+
+static int sama5d4_wdt_init(struct sama5d4_wdt *wdt)
+{
+ struct watchdog_device *wdd = &wdt->wdd;
+ u32 value = WDT_SEC2TICKS(wdd->timeout);
+ u32 reg;
+
+ /*
+ * Because the fields WDV and WDD must not be modified when the WDDIS
+ * bit is set, so clear the WDDIS bit before writing the WDT_MR.
+ */
+ reg = wdt_read(wdt, AT91_WDT_MR);
+ reg &= ~AT91_WDT_WDDIS;
+ wdt_write(wdt, AT91_WDT_MR, reg);
+
+ reg = wdt->config;
+ reg |= AT91_WDT_SET_WDD(value);
+ reg |= AT91_WDT_SET_WDV(value);
+
+ wdt_write(wdt, AT91_WDT_MR, reg);
+
+ return 0;
+}
+
+static int sama5d4_wdt_probe(struct platform_device *pdev)
+{
+ struct watchdog_device *wdd;
+ struct sama5d4_wdt *wdt;
+ struct resource *res;
+ void __iomem *regs;
+ u32 irq = 0;
+ int ret;
+
+ wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
+ if (!wdt)
+ return -ENOMEM;
+
+ wdd = &wdt->wdd;
+ wdd->timeout = wdt_timeout;
+ wdd->info = &sama5d4_wdt_info;
+ wdd->ops = &sama5d4_wdt_ops;
+ wdd->min_timeout = MIN_WDT_TIMEOUT;
+ wdd->max_timeout = MAX_WDT_TIMEOUT;
+
+ watchdog_set_drvdata(wdd, wdt);
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ regs = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(regs))
+ return PTR_ERR(regs);
+
+ wdt->reg_base = regs;
+
+ if (pdev->dev.of_node) {
+ irq = irq_of_parse_and_map(pdev->dev.of_node, 0);
+ if (!irq)
+ dev_warn(&pdev->dev, "failed to get IRQ from DT\n");
+
+ ret = of_sama5d4_wdt_init(pdev->dev.of_node, wdt);
+ if (ret)
+ return ret;
+ }
+
+ if ((wdt->config & AT91_WDT_WDFIEN) && irq) {
+ ret = devm_request_irq(&pdev->dev, irq, sama5d4_wdt_irq_handler,
+ IRQF_SHARED | IRQF_IRQPOLL |
+ IRQF_NO_SUSPEND, pdev->name, pdev);
+ if (ret) {
+ dev_err(&pdev->dev,
+ "cannot register interrupt handler\n");
+ return ret;
+ }
+ }
+
+ ret = watchdog_init_timeout(wdd, wdt_timeout, &pdev->dev);
+ if (ret) {
+ dev_err(&pdev->dev, "unable to set timeout value\n");
+ return ret;
+ }
+
+ ret = sama5d4_wdt_init(wdt);
+ if (ret)
+ return ret;
+
+ watchdog_set_nowayout(wdd, nowayout);
+
+ ret = watchdog_register_device(wdd);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to register watchdog device\n");
+ return ret;
+ }
+
+ platform_set_drvdata(pdev, wdt);
+
+ dev_info(&pdev->dev, "initialized (timeout = %d sec, nowayout = %d)\n",
+ wdt_timeout, nowayout);
+
+ return 0;
+}
+
+static int sama5d4_wdt_remove(struct platform_device *pdev)
+{
+ struct sama5d4_wdt *wdt = platform_get_drvdata(pdev);
+
+ sama5d4_wdt_stop(&wdt->wdd);
+
+ watchdog_unregister_device(&wdt->wdd);
+
+ return 0;
+}
+
+static const struct of_device_id sama5d4_wdt_of_match[] = {
+ { .compatible = "atmel,sama5d4-wdt", },
+ { }
+};
+MODULE_DEVICE_TABLE(of, sama5d4_wdt_of_match);
+
+static struct platform_driver sama5d4_wdt_driver = {
+ .probe = sama5d4_wdt_probe,
+ .remove = sama5d4_wdt_remove,
+ .driver = {
+ .name = "sama5d4_wdt",
+ .of_match_table = sama5d4_wdt_of_match,
+ }
+};
+module_platform_driver(sama5d4_wdt_driver);
+
+MODULE_AUTHOR("Atmel Corporation");
+MODULE_DESCRIPTION("Atmel SAMA5D4 Watchdog Timer driver");
+MODULE_LICENSE("GPL v2");
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