watchdog: implement bcm2835 watchdog

Move out of architecture code and add some real watchdog functionality.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

3 files changed, 148 insertions, 0 deletions

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index a8f9492ac3..3defb9da61 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -58,4 +58,10 @@ config WATCHDOG_ORION
 	help
 	  Add support for watchdog on the Marvall Armada XP
 
+config WATCHDOG_BCM2835
+	bool "Watchdog for BCM283x SoCs"
+	depends on ARCH_BCM283X
+	help
+	  Add support for watchdog on the Broadcom BCM283X SoCs.
+
 endif
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index c607f75090..2376401213 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -7,3 +7,4 @@ obj-$(CONFIG_WATCHDOG_DW) += dw_wdt.o
 obj-$(CONFIG_WATCHDOG_JZ4740) += jz4740.o
 obj-$(CONFIG_WATCHDOG_IMX_RESET_SOURCE) += imxwd.o
 obj-$(CONFIG_WATCHDOG_ORION) += orion_wdt.o
+obj-$(CONFIG_ARCH_BCM283X) += bcm2835_wdt.o
diff --git a/drivers/watchdog/bcm2835_wdt.c b/drivers/watchdog/bcm2835_wdt.c
new file mode 100644
index 0000000000..457d86fc04
--- /dev/null
+++ b/drivers/watchdog/bcm2835_wdt.c
@@ -0,0 +1,141 @@
+/*
+ * Copyright (C) 2017 Pengutronix, Lucas Stach <l.stach@pengutronix.de>
+ *
+ * Based on code from  Carlo Caione <carlo@carlocaione.org>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+#include <common.h>
+#include <init.h>
+#include <io.h>
+#include <restart.h>
+#include <watchdog.h>
+
+#define PM_RSTC		0x1c
+#define PM_RSTS		0x20
+#define PM_WDOG		0x24
+
+#define PM_WDOG_RESET				0000000000
+#define PM_PASSWORD				0x5a000000
+#define PM_WDOG_TIME_SET			0x000fffff
+#define PM_RSTC_WRCFG_CLR			0xffffffcf
+#define PM_RSTC_WRCFG_SET			0x00000030
+#define PM_RSTC_WRCFG_FULL_RESET		0x00000020
+#define PM_RSTC_RESET				0x00000102
+
+#define PM_RSTS_HADPOR_SET			0x00001000
+#define PM_RSTS_HADSRH_SET			0x00000400
+#define PM_RSTS_HADSRF_SET			0x00000200
+#define PM_RSTS_HADSRQ_SET			0x00000100
+#define PM_RSTS_HADWRH_SET			0x00000040
+#define PM_RSTS_HADWRF_SET			0x00000020
+#define PM_RSTS_HADWRQ_SET			0x00000010
+#define PM_RSTS_HADDRH_SET			0x00000004
+#define PM_RSTS_HADDRF_SET			0x00000002
+#define PM_RSTS_HADDRQ_SET			0x00000001
+
+#define SECS_TO_WDOG_TICKS(x) ((x) << 16)
+
+struct bcm2835_wd {
+	struct watchdog wd;
+	void __iomem *base;
+	struct device_d *dev;
+	struct restart_handler restart;
+};
+
+#define RESET_TIMEOUT 10
+
+static void __noreturn bcm2835_restart_soc(struct restart_handler *rst)
+{
+	struct bcm2835_wd *priv = container_of(rst, struct bcm2835_wd, restart);
+	uint32_t rstc;
+
+	rstc = readl(priv->base + PM_RSTC);
+	rstc &= ~PM_RSTC_WRCFG_SET;
+	rstc |= PM_RSTC_WRCFG_FULL_RESET;
+	writel(PM_PASSWORD | RESET_TIMEOUT, priv->base +  PM_WDOG);
+	writel(PM_PASSWORD | rstc, priv->base + PM_RSTC);
+
+	hang();
+}
+
+static int bcm2835_wd_set_timeout(struct watchdog *wd, unsigned timeout)
+{
+	struct bcm2835_wd *priv = container_of(wd, struct bcm2835_wd, wd);
+	u32 val;
+
+	if (!timeout) {
+		writel(PM_PASSWORD | PM_RSTC_RESET, priv->base + PM_RSTC);
+		return 0;
+	}
+
+	writel(PM_PASSWORD | (SECS_TO_WDOG_TICKS(timeout) & PM_WDOG_TIME_SET),
+	       priv->base + PM_WDOG);
+	val = readl(priv->base + PM_RSTC);
+	writel(PM_PASSWORD | (val & PM_RSTC_WRCFG_CLR) |
+	       PM_RSTC_WRCFG_FULL_RESET, priv->base + PM_RSTC);
+
+	return 0;
+}
+
+static int bcm2835_wd_probe(struct device_d *dev)
+{
+	struct resource *iores;
+	struct bcm2835_wd *priv;
+	int ret;
+
+	priv = xzalloc(sizeof(*priv));
+	iores = dev_request_mem_resource(dev, 0);
+	if (IS_ERR(iores)) {
+		dev_err(dev, "could not get memory region\n");
+		return PTR_ERR(iores);
+	}
+	priv->base = IOMEM(iores->start);
+	priv->wd.set_timeout = bcm2835_wd_set_timeout;
+	priv->wd.dev = dev;
+	priv->dev = dev;
+
+	if (IS_ENABLED(CONFIG_WATCHDOG_BCM2835)) {
+		ret = watchdog_register(&priv->wd);
+		if (ret) {
+			free(priv);
+			return ret;
+		}
+	}
+
+	priv->restart.name = "bcm2835_wd";
+	priv->restart.restart = bcm2835_restart_soc;
+
+	restart_handler_register(&priv->restart);
+
+	return 0;
+}
+
+static __maybe_unused struct of_device_id bcm2835_wd_dt_ids[] = {
+	{
+		.compatible = "brcm,bcm2835-pm-wdt",
+	}, {
+		/* sentinel */
+	},
+};
+
+static struct driver_d bcm2835_wd_driver = {
+	.name		= "bcm2835_wd",
+	.of_compatible	= DRV_OF_COMPAT(bcm2835_wd_dt_ids),
+	.probe		= bcm2835_wd_probe,
+};
+
+static int __init bcm2835_wd_init(void)
+{
+	return platform_driver_register(&bcm2835_wd_driver);
+}
+device_initcall(bcm2835_wd_init);