dm: watchdog: add BCM6345 watchdog driver

This driver is a simplified version of linux/drivers/watchdog/bcm63xx_wdt.c

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

drivers/watchdog/Kconfig

@@ -54,4 +54,12 @@ config WDT_ASPEED
 	  It currently does not support Boot Flash Addressing Mode Detection or
 	  Second Boot.
 
+config WDT_BCM6345
+	bool "BCM6345 watchdog timer support"
+	depends on WDT && ARCH_BMIPS
+	help
+	  Select this to enable watchdog timer for BCM6345 SoCs.
+	  The watchdog timer is stopped when initialized.
+	  It performs full SoC reset.
+
 endmenu

drivers/watchdog/Makefile

@@ -18,4 +18,5 @@ obj-$(CONFIG_ULP_WATCHDOG) += ulp_wdog.o
 obj-$(CONFIG_WDT) += wdt-uclass.o
 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

drivers/watchdog/bcm6345_wdt.c

@@ -0,0 +1,110 @@
+/*
+ * Copyright (C) 2017 Álvaro Fernández Rojas <noltari@gmail.com>
+ *
+ * Derived from linux/drivers/watchdog/bcm63xx_wdt.c:
+ *	Copyright (C) 2007 Miguel Gaio <miguel.gaio@efixo.com>
+ *	Copyright (C) 2008 Florian Fainelli <florian@openwrt.org>
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <wdt.h>
+#include <asm/io.h>
+
+/* WDT Value register */
+#define WDT_VAL_REG		0x0
+#define WDT_VAL_MIN		0x00000002
+#define WDT_VAL_MAX		0xfffffffe
+
+/* WDT Control register */
+#define WDT_CTL_REG		0x4
+#define WDT_CTL_START1_MASK	0x0000ff00
+#define WDT_CTL_START2_MASK	0x000000ff
+#define WDT_CTL_STOP1_MASK	0x0000ee00
+#define WDT_CTL_STOP2_MASK	0x000000ee
+
+struct bcm6345_wdt_priv {
+	void __iomem *regs;
+};
+
+static int bcm6345_wdt_reset(struct udevice *dev)
+{
+	struct bcm6345_wdt_priv *priv = dev_get_priv(dev);
+
+	writel_be(WDT_CTL_START1_MASK, priv->regs + WDT_CTL_REG);
+	writel_be(WDT_CTL_START2_MASK, priv->regs + WDT_CTL_REG);
+
+	return 0;
+}
+
+static int bcm6345_wdt_start(struct udevice *dev, u64 timeout, ulong flags)
+{
+	struct bcm6345_wdt_priv *priv = dev_get_priv(dev);
+
+	if (timeout < WDT_VAL_MIN) {
+		debug("watchdog won't fire with less than 2 ticks\n");
+		timeout = WDT_VAL_MIN;
+	} else if (timeout > WDT_VAL_MAX) {
+		debug("maximum watchdog timeout exceeded\n");
+		timeout = WDT_VAL_MAX;
+	}
+
+	writel_be(timeout, priv->regs + WDT_VAL_REG);
+
+	return bcm6345_wdt_reset(dev);
+}
+
+static int bcm6345_wdt_expire_now(struct udevice *dev, ulong flags)
+{
+	return bcm6345_wdt_start(dev, WDT_VAL_MIN, flags);
+}
+
+static int bcm6345_wdt_stop(struct udevice *dev)
+{
+	struct bcm6345_wdt_priv *priv = dev_get_priv(dev);
+
+	writel_be(WDT_CTL_STOP1_MASK, priv->regs + WDT_CTL_REG);
+	writel_be(WDT_CTL_STOP2_MASK, priv->regs + WDT_CTL_REG);
+
+	return 0;
+}
+
+static const struct wdt_ops bcm6345_wdt_ops = {
+	.expire_now = bcm6345_wdt_expire_now,
+	.reset = bcm6345_wdt_reset,
+	.start = bcm6345_wdt_start,
+	.stop = bcm6345_wdt_stop,
+};
+
+static const struct udevice_id bcm6345_wdt_ids[] = {
+	{ .compatible = "brcm,bcm6345-wdt" },
+	{ /* sentinel */ }
+};
+
+static int bcm6345_wdt_probe(struct udevice *dev)
+{
+	struct bcm6345_wdt_priv *priv = dev_get_priv(dev);
+	fdt_addr_t addr;
+	fdt_size_t size;
+
+	addr = dev_get_addr_size_index(dev, 0, &size);
+	if (addr == FDT_ADDR_T_NONE)
+		return -EINVAL;
+
+	priv->regs = ioremap(addr, size);
+
+	bcm6345_wdt_stop(dev);
+
+	return 0;
+}
+
+U_BOOT_DRIVER(wdt_bcm6345) = {
+	.name = "wdt_bcm6345",
+	.id = UCLASS_WDT,
+	.of_match = bcm6345_wdt_ids,
+	.ops = &bcm6345_wdt_ops,
+	.priv_auto_alloc_size = sizeof(struct bcm6345_wdt_priv),
+	.probe = bcm6345_wdt_probe,
+};