1 files changed, 132 insertions, 0 deletions
diff --git a/drivers/watchdog/bcm2835_wdt.c b/drivers/watchdog/bcm2835_wdt.c
new file mode 100644
index 0000000000..3c1ead3dda
--- /dev/null
+++ b/drivers/watchdog/bcm2835_wdt.c
@@ -0,0 +1,132 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2013 Lubomir Rintel <lkundrak@v3.sk>
+ * Copyright (C) 2023 Etienne Dublé (CNRS) <etienne.duble@imag.fr>
+ *
+ * This code is mostly derived from the linux driver.
+ */
+
+#include <dm.h>
+#include <wdt.h>
+#include <asm/io.h>
+#include <linux/delay.h>
+
+#define PM_RSTC					0x1c
+#define PM_WDOG					0x24
+
+#define PM_PASSWORD				0x5a000000
+
+/* The hardware supports a maximum timeout value of 0xfffff ticks
+ * (just below 16 seconds).
+ */
+#define PM_WDOG_MAX_TICKS			0x000fffff
+#define PM_RSTC_WRCFG_CLR			0xffffffcf
+#define PM_RSTC_WRCFG_FULL_RESET		0x00000020
+#define PM_RSTC_RESET				0x00000102
+
+#define MS_TO_WDOG_TICKS(x) (((x) << 16) / 1000)
+
+struct bcm2835_wdt_priv {
+	void __iomem *base;
+	u64 timeout_ticks;
+};
+
+static int bcm2835_wdt_start_ticks(struct udevice *dev,
+				   u64 timeout_ticks, ulong flags)
+{
+	struct bcm2835_wdt_priv *priv = dev_get_priv(dev);
+	void __iomem *base = priv->base;
+	u32 cur;
+
+	writel(PM_PASSWORD | timeout_ticks, base + PM_WDOG);
+	cur = readl(base + PM_RSTC);
+	writel(PM_PASSWORD | (cur & PM_RSTC_WRCFG_CLR) | PM_RSTC_WRCFG_FULL_RESET,
+	       base + PM_RSTC);
+
+	return 0;
+}
+
+static int bcm2835_wdt_start(struct udevice *dev, u64 timeout_ms, ulong flags)
+{
+	struct bcm2835_wdt_priv *priv = dev_get_priv(dev);
+
+	priv->timeout_ticks = MS_TO_WDOG_TICKS(timeout_ms);
+
+	if (priv->timeout_ticks > PM_WDOG_MAX_TICKS) {
+		printf("bcm2835_wdt: the timeout value is too high, using ~16s instead.\n");
+		priv->timeout_ticks = PM_WDOG_MAX_TICKS;
+	}
+
+	return bcm2835_wdt_start_ticks(dev, priv->timeout_ticks, flags);
+}
+
+static int bcm2835_wdt_reset(struct udevice *dev)
+{
+	struct bcm2835_wdt_priv *priv = dev_get_priv(dev);
+
+	/* restart the timer with the value of priv->timeout_ticks
+	 * saved from the last bcm2835_wdt_start() call.
+	 */
+	return bcm2835_wdt_start_ticks(dev, priv->timeout_ticks, 0);
+}
+
+static int bcm2835_wdt_stop(struct udevice *dev)
+{
+	struct bcm2835_wdt_priv *priv = dev_get_priv(dev);
+	void __iomem *base = priv->base;
+
+	writel(PM_PASSWORD | PM_RSTC_RESET, base + PM_RSTC);
+
+	return 0;
+}
+
+static int bcm2835_wdt_expire_now(struct udevice *dev, ulong flags)
+{
+	int ret;
+
+	/* use a timeout of 10 ticks (~150us) */
+	ret = bcm2835_wdt_start_ticks(dev, 10, flags);
+	if (ret)
+		return ret;
+
+	mdelay(500);
+
+	return 0;
+}
+
+static const struct wdt_ops bcm2835_wdt_ops = {
+	.reset		= bcm2835_wdt_reset,
+	.start		= bcm2835_wdt_start,
+	.stop		= bcm2835_wdt_stop,
+	.expire_now	= bcm2835_wdt_expire_now,
+};
+
+static const struct udevice_id bcm2835_wdt_ids[] = {
+	{ .compatible = "brcm,bcm2835-pm" },
+	{ .compatible = "brcm,bcm2835-pm-wdt" },
+	{ /* sentinel */ }
+};
+
+static int bcm2835_wdt_probe(struct udevice *dev)
+{
+	struct bcm2835_wdt_priv *priv = dev_get_priv(dev);
+
+	priv->base = dev_remap_addr(dev);
+	if (!priv->base)
+		return -EINVAL;
+
+	priv->timeout_ticks = PM_WDOG_MAX_TICKS;
+
+	bcm2835_wdt_stop(dev);
+
+	return 0;
+}
+
+U_BOOT_DRIVER(bcm2835_wdt) = {
+	.name		= "bcm2835_wdt",
+	.id		= UCLASS_WDT,
+	.of_match	= bcm2835_wdt_ids,
+	.probe		= bcm2835_wdt_probe,
+	.priv_auto	= sizeof(struct bcm2835_wdt_priv),
+	.ops		= &bcm2835_wdt_ops,
+};