[PATCH 19/20] watchdog: add StarFive watchdog driver

[Ahmad Fatoum]

Signed-off-by: Ahmad Fatoum <a.fatoum at pengutronix.de>
---
 drivers/watchdog/Kconfig        |  7 +++
 drivers/watchdog/Makefile       |  1 +
 drivers/watchdog/starfive_wdt.c | 97 +++++++++++++++++++++++++++++++++
 3 files changed, 105 insertions(+)
 create mode 100644 drivers/watchdog/starfive_wdt.c

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 542659825045..8aeca0bd6f5f 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -148,4 +148,11 @@ config ITCO_WDT
 	  NO_REBOOT flag which prevents the watchdog from rebooting the
 	  machine.
 
+config STARFIVE_WDT
+	tristate "StarFive Watchdog Timer"
+	depends on SOC_STARFIVE && OFDEVICE
+	help
+	  If you say yes here you get support for the watchdog device
+	  on StarFive SoCs.
+
 endif
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 0b598af40218..4e784b5aaa30 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -18,3 +18,4 @@ obj-$(CONFIG_STPMIC1_WATCHDOG) += stpmic1_wdt.o
 obj-$(CONFIG_F71808E_WDT) += f71808e_wdt.o
 obj-$(CONFIG_GPIO_WATCHDOG) += gpio_wdt.o
 obj-$(CONFIG_ITCO_WDT) += itco_wdt.o
+obj-$(CONFIG_STARFIVE_WDT) += starfive_wdt.o
diff --git a/drivers/watchdog/starfive_wdt.c b/drivers/watchdog/starfive_wdt.c
new file mode 100644
index 000000000000..abe20f7a1a82
--- /dev/null
+++ b/drivers/watchdog/starfive_wdt.c
@@ -0,0 +1,97 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2018 Kalray Inc.
+ */
+
+#include <common.h>
+#include <init.h>
+#include <io.h>
+#include <of.h>
+#include <watchdog.h>
+#include <linux/reset.h>
+
+#include <linux/clk.h>
+#include <linux/err.h>
+
+#define WDT_REG_RESET_EN	0x104
+#define WDT_REG_TIMEOUT		0x108
+#define WDT_REG_CONTROL		0x110
+#define WDT_REG_UNLOCK		0x13c
+
+#define WDT_UNLOCK_KEY	0x378f0765
+
+struct starfive_wdt {
+	uint32_t clk_rate;
+	struct watchdog wdd;
+	void __iomem *base;
+	bool setup;
+};
+
+static int starfive_wdt_set_timeout(struct watchdog *wdd, unsigned int timeout)
+{
+	struct starfive_wdt *wd = container_of(wdd, struct starfive_wdt, wdd);
+
+	writel(0, wd->base + WDT_REG_CONTROL);
+
+	if (timeout > 0) {
+		timeout *= wd->clk_rate;
+		writel(timeout, wd->base + WDT_REG_TIMEOUT);
+		writel(1, wd->base + WDT_REG_CONTROL);
+	}
+
+	return 0;
+}
+
+static int starfive_wdt_drv_probe(struct device_d *dev)
+{
+	struct starfive_wdt *wd;
+	struct resource *iores;
+	struct watchdog *wdd;
+	struct clk *clk;
+	int ret;
+
+	clk = clk_get(dev, NULL);
+	if (IS_ERR(clk))
+		return PTR_ERR(clk);
+
+	iores = dev_request_mem_resource(dev, 0);
+	if (IS_ERR(iores))
+		return PTR_ERR(iores);
+
+	wd = xzalloc(sizeof(*wd));
+	wd->base = IOMEM(iores->start);
+
+	wd->clk_rate = clk_get_rate(clk);
+
+	ret = device_reset_all(dev);
+	if (ret)
+		return ret;
+
+	writel(WDT_UNLOCK_KEY, wd->base + WDT_REG_UNLOCK);
+	wd->base = IOMEM(iores->start);
+	/* reset, not interrupt, on timer expiry */
+	writel(1, wd->base + WDT_REG_RESET_EN);
+
+	wdd = &wd->wdd;
+	wdd->name = "starfive_wdt";
+	wdd->hwdev = dev;
+	wdd->set_timeout = starfive_wdt_set_timeout;
+	wdd->timeout_max = U32_MAX / wd->clk_rate;
+
+	wdd->running = readl(wd->base + WDT_REG_CONTROL) & 1 ?
+		WDOG_HW_RUNNING : WDOG_HW_NOT_RUNNING;
+
+	return watchdog_register(wdd);
+}
+
+static struct of_device_id starfive_wdt_of_match[] = {
+	{ .compatible = "starfive,wdt", },
+	{ /* sentinel */ }
+};
+
+static struct driver_d starfive_wdt_driver = {
+	.name		= "starfive-wdt",
+	.probe		= starfive_wdt_drv_probe,
+	.of_compatible	= starfive_wdt_of_match,
+};
+device_platform_driver(starfive_wdt_driver);
-- 
2.29.2