1 files changed, 109 insertions, 0 deletions
diff --git a/drivers/watchdog/at91sam9_wdt.c b/drivers/watchdog/at91sam9_wdt.c
new file mode 100644
index 0000000000..3f554bf47b
--- /dev/null
+++ b/drivers/watchdog/at91sam9_wdt.c
@@ -0,0 +1,109 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 Pengutronix, Ahmad Fatoum <a.fatoum@pengutronix.de>
+ */
+
+#include <common.h>
+#include <init.h>
+#include <io.h>
+#include <watchdog.h>
+#include <linux/clk.h>
+#include <mach/at91_wdt.h>
+
+#define MIN_WDT_TIMEOUT		1
+#define MAX_WDT_TIMEOUT		16
+#define SECS_TO_WDOG_TICKS(s)	((s) ? (((s) << 8) - 1) : 0)
+
+struct at91sam9x_wdt {
+	struct watchdog wdd;
+	void __iomem *base;
+};
+
+static inline void at91sam9x_wdt_ping(struct at91sam9x_wdt *wdt)
+{
+	writel(AT91_WDT_WDRSTT | AT91_WDT_KEY, wdt->base + AT91_WDT_CR);
+}
+
+static int at91sam9x_wdt_set_timeout(struct watchdog *wdd, unsigned timeout)
+{
+	struct at91sam9x_wdt *wdt = container_of(wdd, struct at91sam9x_wdt, wdd);
+	u32 mr_old, mr_new;
+
+	mr_old = readl(wdt->base + AT91_WDT_MR);
+
+	if (!timeout) {
+		mr_new = mr_old | AT91_WDT_WDDIS;
+		writel(mr_new, wdt->base + AT91_WDT_MR);
+		return 0;
+	}
+
+	mr_new = AT91_WDT_WDRSTEN
+		| AT91_WDT_WDDBGHLT | AT91_WDT_WDIDLEHLT
+		| AT91_WDT_WDD
+		| (SECS_TO_WDOG_TICKS(timeout) & AT91_WDT_WDV);
+
+	if (mr_new != mr_old)
+		writel(mr_new, wdt->base + AT91_WDT_MR);
+
+	at91sam9x_wdt_ping(wdt);
+	return 0;
+}
+
+static inline bool at91sam9x_wdt_is_disabled(struct at91sam9x_wdt *wdt)
+{
+	return readl(wdt->base + AT91_WDT_MR) & AT91_WDT_WDDIS;
+}
+
+static int at91sam9x_wdt_probe(struct device_d *dev)
+{
+	struct at91sam9x_wdt *wdt;
+	struct resource *iores;
+	struct clk *clk;
+	int ret;
+
+	wdt = xzalloc(sizeof(*wdt));
+	iores = dev_request_mem_resource(dev, 0);
+	if (IS_ERR(iores)) {
+		dev_err(dev, "could not get watchdog memory region\n");
+		return PTR_ERR(iores);
+	}
+	wdt->base = IOMEM(iores->start);
+	clk = clk_get(dev, NULL);
+	if (WARN_ON(IS_ERR(clk)))
+		return PTR_ERR(clk);
+
+	clk_enable(clk);
+
+	wdt->wdd.set_timeout = at91sam9x_wdt_set_timeout;
+	wdt->wdd.timeout_max = MAX_WDT_TIMEOUT;
+	wdt->wdd.hwdev = dev;
+
+	if (at91sam9x_wdt_is_disabled(wdt))
+		wdt->wdd.running = WDOG_HW_NOT_RUNNING;
+	else
+		wdt->wdd.running = WDOG_HW_RUNNING;
+
+	ret = watchdog_register(&wdt->wdd);
+	if (ret)
+		free(wdt);
+
+	return ret;
+}
+
+static const __maybe_unused struct of_device_id at91sam9x_wdt_dt_ids[] = {
+	{ .compatible = "atmel,at91sam9260-wdt", },
+	{ .compatible = "atmel,sama5d4-wdt", },
+	{ /* sentinel */ },
+};
+
+static struct driver_d at91sam9x_wdt_driver = {
+	.name		= "at91sam9x-wdt",
+	.of_compatible	= DRV_OF_COMPAT(at91sam9x_wdt_dt_ids),
+	.probe		= at91sam9x_wdt_probe,
+};
+
+static int __init at91sam9x_wdt_init(void)
+{
+	return platform_driver_register(&at91sam9x_wdt_driver);
+}
+device_initcall(at91sam9x_wdt_init);