--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Starfive Watchdog driver
+ *
+ * Copyright (C) 2022 StarFive Technology Co., Ltd.
+ */
+
+#include <clk.h>
+#include <dm.h>
+#include <reset.h>
+#include <wdt.h>
+#include <linux/iopoll.h>
+
+/* JH7110 Watchdog register define */
+#define STARFIVE_WDT_JH7110_LOAD 0x000
+#define STARFIVE_WDT_JH7110_VALUE 0x004
+#define STARFIVE_WDT_JH7110_CONTROL 0x008 /*
+ * [0]: reset enable;
+ * [1]: interrupt enable && watchdog enable
+ * [31:2]: reserved.
+ */
+#define STARFIVE_WDT_JH7110_INTCLR 0x00c /* clear intterupt and reload the counter */
+#define STARFIVE_WDT_JH7110_IMS 0x014
+#define STARFIVE_WDT_JH7110_LOCK 0xc00 /* write 0x1ACCE551 to unlock */
+
+/* WDOGCONTROL */
+#define STARFIVE_WDT_ENABLE 0x1
+#define STARFIVE_WDT_EN_SHIFT 0
+#define STARFIVE_WDT_RESET_EN 0x1
+#define STARFIVE_WDT_JH7110_RST_EN_SHIFT 1
+
+/* WDOGLOCK */
+#define STARFIVE_WDT_JH7110_UNLOCK_KEY 0x1acce551
+
+/* WDOGINTCLR */
+#define STARFIVE_WDT_INTCLR 0x1
+#define STARFIVE_WDT_JH7100_INTCLR_AVA_SHIFT 1 /* Watchdog can clear interrupt when 0 */
+
+#define STARFIVE_WDT_MAXCNT 0xffffffff
+#define STARFIVE_WDT_DEFAULT_TIME (15)
+#define STARFIVE_WDT_DELAY_US 0
+#define STARFIVE_WDT_TIMEOUT_US 10000
+
+/* module parameter */
+#define STARFIVE_WDT_EARLY_ENA 0
+
+struct starfive_wdt_variant {
+ unsigned int control; /* Watchdog Control Resgister for reset enable */
+ unsigned int load; /* Watchdog Load register */
+ unsigned int reload; /* Watchdog Reload Control register */
+ unsigned int enable; /* Watchdog Enable Register */
+ unsigned int value; /* Watchdog Counter Value Register */
+ unsigned int int_clr; /* Watchdog Interrupt Clear Register */
+ unsigned int unlock; /* Watchdog Lock Register */
+ unsigned int int_status; /* Watchdog Interrupt Status Register */
+
+ u32 unlock_key;
+ char enrst_shift;
+ char en_shift;
+ bool intclr_check; /* whether need to check it before clearing interrupt */
+ char intclr_ava_shift;
+ bool double_timeout; /* The watchdog need twice timeout to reboot */
+};
+
+struct starfive_wdt_priv {
+ void __iomem *base;
+ struct clk *core_clk;
+ struct clk *apb_clk;
+ struct reset_ctl_bulk *rst;
+ const struct starfive_wdt_variant *variant;
+ unsigned long freq;
+ u32 count; /* count of timeout */
+ u32 reload; /* restore the count */
+};
+
+/* Register layout and configuration for the JH7110 */
+static const struct starfive_wdt_variant starfive_wdt_jh7110_variant = {
+ .control = STARFIVE_WDT_JH7110_CONTROL,
+ .load = STARFIVE_WDT_JH7110_LOAD,
+ .enable = STARFIVE_WDT_JH7110_CONTROL,
+ .value = STARFIVE_WDT_JH7110_VALUE,
+ .int_clr = STARFIVE_WDT_JH7110_INTCLR,
+ .unlock = STARFIVE_WDT_JH7110_LOCK,
+ .unlock_key = STARFIVE_WDT_JH7110_UNLOCK_KEY,
+ .int_status = STARFIVE_WDT_JH7110_IMS,
+ .enrst_shift = STARFIVE_WDT_JH7110_RST_EN_SHIFT,
+ .en_shift = STARFIVE_WDT_EN_SHIFT,
+ .intclr_check = false,
+ .double_timeout = true,
+};
+
+static int starfive_wdt_enable_clock(struct starfive_wdt_priv *wdt)
+{
+ int ret;
+
+ ret = clk_enable(wdt->apb_clk);
+ if (ret)
+ return ret;
+
+ ret = clk_enable(wdt->core_clk);
+ if (ret) {
+ clk_disable(wdt->apb_clk);
+ return ret;
+ }
+
+ return 0;
+}
+
+static void starfive_wdt_disable_clock(struct starfive_wdt_priv *wdt)
+{
+ clk_disable(wdt->core_clk);
+ clk_disable(wdt->apb_clk);
+}
+
+/* Write unlock-key to unlock. Write other value to lock. */
+static void starfive_wdt_unlock(struct starfive_wdt_priv *wdt)
+{
+ writel(wdt->variant->unlock_key, wdt->base + wdt->variant->unlock);
+}
+
+static void starfive_wdt_lock(struct starfive_wdt_priv *wdt)
+{
+ writel(~wdt->variant->unlock_key, wdt->base + wdt->variant->unlock);
+}
+
+/* enable watchdog interrupt to reset/reboot */
+static void starfive_wdt_enable_reset(struct starfive_wdt_priv *wdt)
+{
+ u32 val;
+
+ val = readl(wdt->base + wdt->variant->control);
+ val |= STARFIVE_WDT_RESET_EN << wdt->variant->enrst_shift;
+ writel(val, wdt->base + wdt->variant->control);
+}
+
+/* waiting interrupt can be free to clear */
+static int starfive_wdt_wait_int_free(struct starfive_wdt_priv *wdt)
+{
+ u32 value;
+
+ return readl_poll_timeout(wdt->base + wdt->variant->int_clr, value,
+ !(value & BIT(wdt->variant->intclr_ava_shift)),
+ STARFIVE_WDT_TIMEOUT_US);
+}
+
+/* clear interrupt signal before initialization or reload */
+static int starfive_wdt_int_clr(struct starfive_wdt_priv *wdt)
+{
+ int ret;
+
+ if (wdt->variant->intclr_check) {
+ ret = starfive_wdt_wait_int_free(wdt);
+ if (ret)
+ return ret;
+ }
+ writel(STARFIVE_WDT_INTCLR, wdt->base + wdt->variant->int_clr);
+
+ return 0;
+}
+
+static inline void starfive_wdt_set_count(struct starfive_wdt_priv *wdt,
+ u32 val)
+{
+ writel(val, wdt->base + wdt->variant->load);
+}
+
+/* enable watchdog */
+static inline void starfive_wdt_enable(struct starfive_wdt_priv *wdt)
+{
+ u32 val;
+
+ val = readl(wdt->base + wdt->variant->enable);
+ val |= STARFIVE_WDT_ENABLE << wdt->variant->en_shift;
+ writel(val, wdt->base + wdt->variant->enable);
+}
+
+/* disable watchdog */
+static inline void starfive_wdt_disable(struct starfive_wdt_priv *wdt)
+{
+ u32 val;
+
+ val = readl(wdt->base + wdt->variant->enable);
+ val &= ~(STARFIVE_WDT_ENABLE << wdt->variant->en_shift);
+ writel(val, wdt->base + wdt->variant->enable);
+}
+
+static inline void starfive_wdt_set_reload_count(struct starfive_wdt_priv *wdt,
+ u32 count)
+{
+ starfive_wdt_set_count(wdt, count);
+
+ /* 7100 need set any value to reload register and could reload value to counter */
+ if (wdt->variant->reload)
+ writel(0x1, wdt->base + wdt->variant->reload);
+}
+
+static int starfive_wdt_start(struct udevice *dev, u64 timeout_ms, ulong flags)
+{
+ int ret;
+ struct starfive_wdt_priv *wdt = dev_get_priv(dev);
+
+ starfive_wdt_unlock(wdt);
+ /* disable watchdog, to be safe */
+ starfive_wdt_disable(wdt);
+
+ starfive_wdt_enable_reset(wdt);
+ ret = starfive_wdt_int_clr(wdt);
+ if (ret)
+ goto exit;
+
+ wdt->count = (timeout_ms / 1000) * wdt->freq;
+ if (wdt->variant->double_timeout)
+ wdt->count /= 2;
+
+ starfive_wdt_set_count(wdt, wdt->count);
+ starfive_wdt_enable(wdt);
+
+exit:
+ starfive_wdt_lock(wdt);
+ return ret;
+}
+
+static int starfive_wdt_stop(struct udevice *dev)
+{
+ struct starfive_wdt_priv *wdt = dev_get_priv(dev);
+
+ starfive_wdt_unlock(wdt);
+ starfive_wdt_disable(wdt);
+ starfive_wdt_lock(wdt);
+
+ return 0;
+}
+
+static int starfive_wdt_reset(struct udevice *dev)
+{
+ int ret;
+ struct starfive_wdt_priv *wdt = dev_get_priv(dev);
+
+ starfive_wdt_unlock(wdt);
+ ret = starfive_wdt_int_clr(wdt);
+ if (ret)
+ goto exit;
+
+ starfive_wdt_set_reload_count(wdt, wdt->count);
+
+exit:
+ starfive_wdt_lock(wdt);
+
+ return ret;
+}
+
+static const struct wdt_ops starfive_wdt_ops = {
+ .start = starfive_wdt_start,
+ .stop = starfive_wdt_stop,
+ .reset = starfive_wdt_reset,
+};
+
+static int starfive_wdt_probe(struct udevice *dev)
+{
+ struct starfive_wdt_priv *wdt = dev_get_priv(dev);
+ int ret;
+
+ ret = starfive_wdt_enable_clock(wdt);
+ if (ret)
+ return ret;
+
+ ret = reset_deassert_bulk(wdt->rst);
+ if (ret)
+ goto err_reset;
+
+ wdt->variant = (const struct starfive_wdt_variant *)dev_get_driver_data(dev);
+
+ wdt->freq = clk_get_rate(wdt->core_clk);
+ if (!wdt->freq) {
+ ret = -EINVAL;
+ goto err_get_freq;
+ }
+
+ return 0;
+
+err_get_freq:
+ reset_assert_bulk(wdt->rst);
+err_reset:
+ starfive_wdt_disable_clock(wdt);
+
+ return ret;
+}
+
+static int starfive_wdt_of_to_plat(struct udevice *dev)
+{
+ struct starfive_wdt_priv *wdt = dev_get_priv(dev);
+
+ wdt->base = (void *)dev_read_addr(dev);
+ if (!wdt->base)
+ return -ENODEV;
+
+ wdt->apb_clk = devm_clk_get(dev, "apb");
+ if (IS_ERR(wdt->apb_clk))
+ return -ENODEV;
+
+ wdt->core_clk = devm_clk_get(dev, "core");
+ if (IS_ERR(wdt->core_clk))
+ return -ENODEV;
+
+ wdt->rst = devm_reset_bulk_get(dev);
+ if (IS_ERR(wdt->rst))
+ return -ENODEV;
+
+ return 0;
+}
+
+static const struct udevice_id starfive_wdt_ids[] = {
+ {
+ .compatible = "starfive,jh7110-wdt",
+ .data = (ulong)&starfive_wdt_jh7110_variant
+ }, {
+ /* sentinel */
+ }
+};
+
+U_BOOT_DRIVER(starfive_wdt) = {
+ .name = "starfive_wdt",
+ .id = UCLASS_WDT,
+ .of_match = starfive_wdt_ids,
+ .priv_auto = sizeof(struct starfive_wdt_priv),
+ .probe = starfive_wdt_probe,
+ .of_to_plat = starfive_wdt_of_to_plat,
+ .ops = &starfive_wdt_ops,
+};
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