--- /dev/null
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c) Siemens AG, 2020
+ *
+ * Authors:
+ * Jan Kiszka <jan.kiszka@siemens.com>
+ *
+ * Derived from linux/drivers/watchdog/rti_wdt.c
+ */
+
+#include <common.h>
+#include <clk.h>
+#include <dm.h>
+#include <power-domain.h>
+#include <wdt.h>
+#include <asm/io.h>
+
+/* Timer register set definition */
+#define RTIDWDCTRL 0x90
+#define RTIDWDPRLD 0x94
+#define RTIWDSTATUS 0x98
+#define RTIWDKEY 0x9c
+#define RTIDWDCNTR 0xa0
+#define RTIWWDRXCTRL 0xa4
+#define RTIWWDSIZECTRL 0xa8
+
+#define RTIWWDRX_NMI 0xa
+
+#define RTIWWDSIZE_50P 0x50
+
+#define WDENABLE_KEY 0xa98559da
+
+#define WDKEY_SEQ0 0xe51a
+#define WDKEY_SEQ1 0xa35c
+
+#define WDT_PRELOAD_SHIFT 13
+
+#define WDT_PRELOAD_MAX 0xfff
+
+struct rti_wdt_priv {
+ phys_addr_t regs;
+ unsigned int clk_khz;
+};
+
+static int rti_wdt_start(struct udevice *dev, u64 timeout_ms, ulong flags)
+{
+ struct rti_wdt_priv *priv = dev_get_priv(dev);
+ u32 timer_margin;
+ int ret;
+
+ if (readl(priv->regs + RTIDWDCTRL) == WDENABLE_KEY)
+ return -EBUSY;
+
+ timer_margin = timeout_ms * priv->clk_khz / 1000;
+ timer_margin >>= WDT_PRELOAD_SHIFT;
+ if (timer_margin > WDT_PRELOAD_MAX)
+ timer_margin = WDT_PRELOAD_MAX;
+
+ writel(timer_margin, priv->regs + RTIDWDPRLD);
+ writel(RTIWWDRX_NMI, priv->regs + RTIWWDRXCTRL);
+ writel(RTIWWDSIZE_50P, priv->regs + RTIWWDSIZECTRL);
+
+ readl(priv->regs + RTIWWDSIZECTRL);
+
+ writel(WDENABLE_KEY, priv->regs + RTIDWDCTRL);
+
+ return 0;
+}
+
+static int rti_wdt_reset(struct udevice *dev)
+{
+ struct rti_wdt_priv *priv = dev_get_priv(dev);
+ u32 prld;
+
+ /* Make sure we do not reset too early */
+ prld = readl(priv->regs + RTIDWDPRLD) << WDT_PRELOAD_SHIFT;
+ if (readl(priv->regs + RTIDWDCNTR) >= prld / 2)
+ return -EPERM;
+
+ writel(WDKEY_SEQ0, priv->regs + RTIWDKEY);
+ writel(WDKEY_SEQ1, priv->regs + RTIWDKEY);
+
+ return 0;
+}
+
+static int rti_wdt_probe(struct udevice *dev)
+{
+ struct rti_wdt_priv *priv = dev_get_priv(dev);
+ struct clk clk;
+ int ret;
+
+ priv->regs = devfdt_get_addr(dev);
+ if (!priv->regs)
+ return -EINVAL;
+
+ ret = clk_get_by_index(dev, 0, &clk);
+ if (ret)
+ return ret;
+
+ priv->clk_khz = clk_get_rate(&clk);
+
+ return 0;
+}
+
+static const struct wdt_ops rti_wdt_ops = {
+ .start = rti_wdt_start,
+ .reset = rti_wdt_reset,
+};
+
+static const struct udevice_id rti_wdt_ids[] = {
+ { .compatible = "ti,j7-rti-wdt" },
+ { }
+};
+
+U_BOOT_DRIVER(rti_wdt) = {
+ .name = "rti_wdt",
+ .id = UCLASS_WDT,
+ .of_match = rti_wdt_ids,
+ .ops = &rti_wdt_ops,
+ .probe = rti_wdt_probe,
+ .priv_auto_alloc_size = sizeof(struct rti_wdt_priv),
+ .flags = DM_FLAG_REMOVE_WITH_PD_ON,
+};