[PATCH 2/2] watchdog: new driver for Armada XP

[Uwe Kleine-König]

This SoC uses a variant of the IP that is also used on most other
Marvell SoCs. For now it only supports Armada XP but the naming is
already chosen such that adding support for further SoCs doesn't result
in much renaming.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig at pengutronix.de>
---
 drivers/watchdog/Kconfig     |   6 +++
 drivers/watchdog/Makefile    |   1 +
 drivers/watchdog/orion_wdt.c | 123 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 130 insertions(+)
 create mode 100644 drivers/watchdog/orion_wdt.c

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 63fb1a8c5701..83b6528a5f5f 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -46,4 +46,10 @@ config WATCHDOG_OMAP
 	help
 	  Add support for watchdog on the TI OMAP SoC.
 
+config WATCHDOG_ORION
+	bool "Watchdog for Armada XP"
+	depends on ARCH_ARMADA_XP
+	help
+	  Add support for watchdog on the Marvall Armada XP
+
 endif
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 5fca4c368c40..a3b26675ce96 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -5,3 +5,4 @@ obj-$(CONFIG_WATCHDOG_MXS28) += im28wd.o
 obj-$(CONFIG_WATCHDOG_DW) += dw_wdt.o
 obj-$(CONFIG_WATCHDOG_JZ4740) += jz4740.o
 obj-$(CONFIG_WATCHDOG_IMX_RESET_SOURCE) += imxwd.o
+obj-$(CONFIG_WATCHDOG_ORION) += orion_wdt.o
diff --git a/drivers/watchdog/orion_wdt.c b/drivers/watchdog/orion_wdt.c
new file mode 100644
index 000000000000..fcdfcd56f9a9
--- /dev/null
+++ b/drivers/watchdog/orion_wdt.c
@@ -0,0 +1,123 @@
+/*
+ * Watchdog driver for Marvell Armada XP.
+ *
+ * Copyright (C) 2017 Pengutronix, Fridolin Tux <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
+ * version 2, as published by the Free Software Foundation.
+ *
+ * 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.
+ */
+
+#include <common.h>
+#include <errno.h>
+#include <init.h>
+#include <io.h>
+#include <malloc.h>
+#include <of.h>
+#include <watchdog.h>
+
+#define CLKRATE 25000000
+
+/* registers relative to timer_base (i.e. first reg property) */
+#define TIMER_CTRL	0x00
+#define TIMER_CTRL_WD_TIMER_25MHZ_EN	BIT(10)
+#define TIMER_CTRL_WD_TIMER_EN		BIT(8)
+
+#define TIMER_STATUS	0x04
+#define TIMER_STATUS_WD_EXPIRED		BIT(31)
+
+#define TIMER_WD_TIMER	0x34
+
+/* registers relative to rstout_base (i.e. second reg property) */
+#define WD_RSTOUTn_MASK	0x00
+#define WD_RSTOUTn_MASK_GLOBAL_WD	BIT(8)
+
+struct orion_wdt_ddata {
+	struct watchdog wd;
+	void __iomem *timer_base;
+	void __iomem *rstout_base;
+};
+
+static int armada_xp_set_timeout(struct watchdog *wd, unsigned timeout)
+{
+	struct orion_wdt_ddata *ddata =
+		container_of(wd, struct orion_wdt_ddata, wd);
+	u32 ctrl;
+
+	if (0xffffffff / CLKRATE < timeout)
+		return -EINVAL;
+
+	ctrl = readl(ddata->timer_base + TIMER_CTRL);
+
+	if (timeout == 0) {
+		/* disable timer */
+		ctrl &= ~TIMER_CTRL_WD_TIMER_EN;
+		writel(ctrl, ddata->timer_base + TIMER_CTRL);
+
+		return 0;
+	}
+
+	/* setup duration */
+	writel(CLKRATE * timeout, ddata->timer_base + TIMER_WD_TIMER);
+
+	/* clear expiration status */
+	writel(readl(ddata->timer_base + TIMER_STATUS) & ~TIMER_STATUS_WD_EXPIRED,
+	       ddata->timer_base + TIMER_STATUS);
+
+	/* assert reset on expiration */
+	writel(WD_RSTOUTn_MASK_GLOBAL_WD, ddata->rstout_base + WD_RSTOUTn_MASK);
+
+	/* enable */
+	ctrl |= TIMER_CTRL_WD_TIMER_25MHZ_EN | TIMER_CTRL_WD_TIMER_EN;
+	writel(ctrl, ddata->timer_base + TIMER_CTRL);
+
+	return 0;
+}
+
+static int orion_wdt_probe(struct device_d *dev)
+{
+	struct orion_wdt_ddata* ddata;
+	struct resource *res_timer, *res_rstout;
+
+	ddata = xzalloc(sizeof(*ddata));
+
+	ddata->wd.set_timeout = armada_xp_set_timeout;
+	ddata->wd.name = "orion_wdt";
+	ddata->wd.dev = dev;
+
+	res_timer = dev_request_mem_resource(dev, 0);
+	if (IS_ERR(res_timer)) {
+		dev_err(dev, "could not get timer memory region\n");
+		return PTR_ERR(res_timer);
+	}
+	ddata->timer_base = IOMEM(res_timer->start);
+
+	res_rstout = dev_request_mem_resource(dev, 1);
+	if (IS_ERR(res_rstout)) {
+		dev_err(dev, "could not get rstout memory region\n");
+		release_region(res_timer);
+
+		return PTR_ERR(res_rstout);
+	}
+	ddata->rstout_base = IOMEM(res_rstout->start);
+
+	return watchdog_register(&ddata->wd);
+}
+
+static const struct of_device_id orion_wdt_of_match[] = {
+	{
+		.compatible = "marvell,armada-xp-wdt",
+	}, { /* sentinel */ }
+};
+
+static struct driver_d orion_wdt_driver = {
+	.probe = orion_wdt_probe,
+	.name = "orion_wdt",
+	.of_compatible = DRV_OF_COMPAT(orion_wdt_of_match),
+};
+device_platform_driver(orion_wdt_driver);
-- 
2.11.0