orion_wdt: Support for the Orion Watchdog

The Orion watchdog can be found on some Marvell Armada chips.

This driver is based on the code by Tomas Hlavacek in the CZ.NIC
turris-omnia-uboot repository, which can be found at
https://gitlab.labs.nic.cz/turris/turris-omnia-uboot, and that
one is based on code by Sylver Bruneau. His code is already in
mainline Linux kernel.

The code uses the new driver model API.

Signed-off-by: Tomas Hlavacek <tomas.hlavacek@nic.cz>
Signed-off-by: Marek Behun <marek.behun@nic.cz>

 create mode 100644 drivers/watchdog/orion_wdt.c
Signed-off-by: Stefan Roese <sr@denx.de>

drivers/watchdog/Kconfig

@@ -62,4 +62,11 @@ config WDT_BCM6345
 	  The watchdog timer is stopped when initialized.
 	  It performs full SoC reset.
 
+config WDT_ORION
+	bool "Orion watchdog timer support"
+	depends on WDT
+	help
+	   Select this to enable Orion watchdog timer, which can be found on some
+	   Marvell Armada chips.
+
 endmenu

drivers/watchdog/Makefile

@@ -20,3 +20,4 @@ obj-$(CONFIG_WDT_SANDBOX) += sandbox_wdt.o
 obj-$(CONFIG_WDT_ASPEED) += ast_wdt.o
 obj-$(CONFIG_WDT_BCM6345) += bcm6345_wdt.o
 obj-$(CONFIG_BCM2835_WDT)       += bcm2835_wdt.o
+obj-$(CONFIG_WDT_ORION) += orion_wdt.o

drivers/watchdog/orion_wdt.c

@@ -0,0 +1,177 @@
+/*
+ * drivers/watchdog/orion_wdt.c
+ *
+ * Watchdog driver for Orion/Kirkwood processors
+ *
+ * Authors:	Tomas Hlavacek <tmshlvck@gmail.com>
+ * 		Sylver Bruneau <sylver.bruneau@googlemail.com>
+ * 		Marek Behun <marek.behun@nic.cz>
+ *
+ * This file is licensed under  the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <wdt.h>
+#include <asm/io.h>
+#include <asm/arch/cpu.h>
+#include <asm/arch/soc.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+struct orion_wdt_priv {
+	void __iomem *reg;
+	int wdt_counter_offset;
+	void __iomem *rstout;
+	void __iomem *rstout_mask;
+	u32 timeout;
+};
+
+#define RSTOUT_ENABLE_BIT		BIT(8)
+#define RSTOUT_MASK_BIT			BIT(10)
+#define WDT_ENABLE_BIT			BIT(8)
+
+#define TIMER_CTRL			0x0000
+#define TIMER_A370_STATUS		0x04
+
+#define WDT_AXP_FIXED_ENABLE_BIT	BIT(10)
+#define WDT_A370_EXPIRED		BIT(31)
+
+static int orion_wdt_reset(struct udevice *dev)
+{
+	struct orion_wdt_priv *priv = dev_get_priv(dev);
+
+	/* Reload watchdog duration */
+	writel(priv->timeout, priv->reg + priv->wdt_counter_offset);
+
+	return 0;
+}
+
+static int orion_wdt_start(struct udevice *dev, u64 timeout, ulong flags)
+{
+	struct orion_wdt_priv *priv = dev_get_priv(dev);
+	u32 reg;
+
+	priv->timeout = (u32) timeout;
+
+	/* Enable the fixed watchdog clock input */
+	reg = readl(priv->reg + TIMER_CTRL);
+	reg |= WDT_AXP_FIXED_ENABLE_BIT;
+	writel(reg, priv->reg + TIMER_CTRL);
+
+	/* Set watchdog duration */
+	writel(priv->timeout, priv->reg + priv->wdt_counter_offset);
+
+	/* Clear the watchdog expiration bit */
+	reg = readl(priv->reg + TIMER_A370_STATUS);
+	reg &= ~WDT_A370_EXPIRED;
+	writel(reg, priv->reg + TIMER_A370_STATUS);
+
+	/* Enable watchdog timer */
+	reg = readl(priv->reg + TIMER_CTRL);
+	reg |= WDT_ENABLE_BIT;
+	writel(reg, priv->reg + TIMER_CTRL);
+
+	/* Enable reset on watchdog */
+	reg = readl(priv->rstout);
+	reg |= RSTOUT_ENABLE_BIT;
+	writel(reg, priv->rstout);
+
+	reg = readl(priv->rstout_mask);
+	reg &= ~RSTOUT_MASK_BIT;
+	writel(reg, priv->rstout_mask);
+
+	return 0;
+}
+
+static int orion_wdt_stop(struct udevice *dev)
+{
+	struct orion_wdt_priv *priv = dev_get_priv(dev);
+	u32 reg;
+
+	/* Disable reset on watchdog */
+	reg = readl(priv->rstout_mask);
+	reg |= RSTOUT_MASK_BIT;
+	writel(reg, priv->rstout_mask);
+
+	reg = readl(priv->rstout);
+	reg &= ~RSTOUT_ENABLE_BIT;
+	writel(reg, priv->rstout);
+
+	/* Disable watchdog timer */
+	reg = readl(priv->reg + TIMER_CTRL);
+	reg &= ~WDT_ENABLE_BIT;
+	writel(reg, priv->reg + TIMER_CTRL);
+
+	return 0;
+}
+
+static inline bool save_reg_from_ofdata(struct udevice *dev, int index,
+					void __iomem **reg, int *offset)
+{
+	fdt_addr_t addr;
+	fdt_size_t off;
+
+	addr = fdtdec_get_addr_size_auto_noparent(
+		gd->fdt_blob, dev_of_offset(dev), "reg", index, &off, true);
+
+	if (addr == FDT_ADDR_T_NONE)
+		return false;
+
+	*reg = (void __iomem *) addr;
+	if (offset)
+		*offset = off;
+
+	return true;
+}
+
+static int orion_wdt_ofdata_to_platdata(struct udevice *dev)
+{
+	struct orion_wdt_priv *priv = dev_get_priv(dev);
+
+	if (!save_reg_from_ofdata(dev, 0, &priv->reg,
+				  &priv->wdt_counter_offset))
+		goto err;
+
+	if (!save_reg_from_ofdata(dev, 1, &priv->rstout, NULL))
+		goto err;
+
+	if (!save_reg_from_ofdata(dev, 2, &priv->rstout_mask, NULL))
+		goto err;
+
+	return 0;
+err:
+	debug("%s: Could not determine Orion wdt IO addresses\n", __func__);
+	return -ENXIO;
+}
+
+static int orion_wdt_probe(struct udevice *dev)
+{
+	debug("%s: Probing wdt%u\n", __func__, dev->seq);
+	orion_wdt_stop(dev);
+
+	return 0;
+}
+
+static const struct wdt_ops orion_wdt_ops = {
+	.start = orion_wdt_start,
+	.reset = orion_wdt_reset,
+	.stop = orion_wdt_stop,
+};
+
+static const struct udevice_id orion_wdt_ids[] = {
+	{ .compatible = "marvell,armada-380-wdt" },
+	{}
+};
+
+U_BOOT_DRIVER(orion_wdt) = {
+	.name = "orion_wdt",
+	.id = UCLASS_WDT,
+	.of_match = orion_wdt_ids,
+	.probe = orion_wdt_probe,
+	.priv_auto_alloc_size = sizeof(struct orion_wdt_priv),
+	.ofdata_to_platdata = orion_wdt_ofdata_to_platdata,
+	.ops = &orion_wdt_ops,
+};