1 files changed, 299 insertions, 0 deletions
diff --git a/drivers/watchdog/max63xx_wdt.c b/drivers/watchdog/max63xx_wdt.c
new file mode 100644
index 0000000000..21935f9620
--- /dev/null
+++ b/drivers/watchdog/max63xx_wdt.c
@@ -0,0 +1,299 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * drivers/char/watchdog/max63xx_wdt.c
+ *
+ * Driver for max63{69,70,71,72,73,74} watchdog timers
+ *
+ * Copyright (C) 2009 Marc Zyngier <maz@misterjones.org>
+ *
+ * This driver assumes the watchdog pins are memory mapped (as it is
+ * the case for the Arcom Zeus). Should it be connected over GPIOs or
+ * another interface, some abstraction will have to be introduced.
+ */
+
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/mod_devicetable.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/watchdog.h>
+#include <linux/bitops.h>
+#include <linux/platform_device.h>
+#include <linux/spinlock.h>
+#include <linux/io.h>
+#include <linux/slab.h>
+#include <linux/property.h>
+
+#define DEFAULT_HEARTBEAT 60
+#define MAX_HEARTBEAT     60
+
+static unsigned int heartbeat = DEFAULT_HEARTBEAT;
+static bool nowayout  = WATCHDOG_NOWAYOUT;
+
+/*
+ * Memory mapping: a single byte, 3 first lower bits to select bit 3
+ * to ping the watchdog.
+ */
+#define MAX6369_WDSET	(7 << 0)
+#define MAX6369_WDI	(1 << 3)
+
+#define MAX6369_WDSET_DISABLED	3
+
+static int nodelay;
+
+struct max63xx_wdt {
+	struct watchdog_device wdd;
+	const struct max63xx_timeout *timeout;
+
+	/* memory mapping */
+	void __iomem *base;
+	spinlock_t lock;
+
+	/* WDI and WSET bits write access routines */
+	void (*ping)(struct max63xx_wdt *wdt);
+	void (*set)(struct max63xx_wdt *wdt, u8 set);
+};
+
+/*
+ * The timeout values used are actually the absolute minimum the chip
+ * offers. Typical values on my board are slightly over twice as long
+ * (10s setting ends up with a 25s timeout), and can be up to 3 times
+ * the nominal setting (according to the datasheet). So please take
+ * these values with a grain of salt. Same goes for the initial delay
+ * "feature". Only max6373/74 have a few settings without this initial
+ * delay (selected with the "nodelay" parameter).
+ *
+ * I also decided to remove from the tables any timeout smaller than a
+ * second, as it looked completly overkill...
+ */
+
+/* Timeouts in second */
+struct max63xx_timeout {
+	const u8 wdset;
+	const u8 tdelay;
+	const u8 twd;
+};
+
+static const struct max63xx_timeout max6369_table[] = {
+	{ 5,  1,  1 },
+	{ 6, 10, 10 },
+	{ 7, 60, 60 },
+	{ },
+};
+
+static const struct max63xx_timeout max6371_table[] = {
+	{ 6, 60,  3 },
+	{ 7, 60, 60 },
+	{ },
+};
+
+static const struct max63xx_timeout max6373_table[] = {
+	{ 2, 60,  1 },
+	{ 5,  0,  1 },
+	{ 1,  3,  3 },
+	{ 7, 60, 10 },
+	{ 6,  0, 10 },
+	{ },
+};
+
+static const struct max63xx_timeout *
+max63xx_select_timeout(const struct max63xx_timeout *table, int value)
+{
+	while (table->twd) {
+		if (value <= table->twd) {
+			if (nodelay && table->tdelay == 0)
+				return table;
+
+			if (!nodelay)
+				return table;
+		}
+
+		table++;
+	}
+
+	return NULL;
+}
+
+static int max63xx_wdt_ping(struct watchdog_device *wdd)
+{
+	struct max63xx_wdt *wdt = watchdog_get_drvdata(wdd);
+
+	wdt->ping(wdt);
+	return 0;
+}
+
+static int max63xx_wdt_start(struct watchdog_device *wdd)
+{
+	struct max63xx_wdt *wdt = watchdog_get_drvdata(wdd);
+
+	wdt->set(wdt, wdt->timeout->wdset);
+
+	/* check for a edge triggered startup */
+	if (wdt->timeout->tdelay == 0)
+		wdt->ping(wdt);
+	return 0;
+}
+
+static int max63xx_wdt_stop(struct watchdog_device *wdd)
+{
+	struct max63xx_wdt *wdt = watchdog_get_drvdata(wdd);
+
+	wdt->set(wdt, MAX6369_WDSET_DISABLED);
+	return 0;
+}
+
+static const struct watchdog_ops max63xx_wdt_ops = {
+	.owner = THIS_MODULE,
+	.start = max63xx_wdt_start,
+	.stop = max63xx_wdt_stop,
+	.ping = max63xx_wdt_ping,
+};
+
+static const struct watchdog_info max63xx_wdt_info = {
+	.options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
+	.identity = "max63xx Watchdog",
+};
+
+static void max63xx_mmap_ping(struct max63xx_wdt *wdt)
+{
+	u8 val;
+
+	spin_lock(&wdt->lock);
+
+	val = __raw_readb(wdt->base);
+
+	__raw_writeb(val | MAX6369_WDI, wdt->base);
+	__raw_writeb(val & ~MAX6369_WDI, wdt->base);
+
+	spin_unlock(&wdt->lock);
+}
+
+static void max63xx_mmap_set(struct max63xx_wdt *wdt, u8 set)
+{
+	u8 val;
+
+	spin_lock(&wdt->lock);
+
+	val = __raw_readb(wdt->base);
+	val &= ~MAX6369_WDSET;
+	val |= set & MAX6369_WDSET;
+	__raw_writeb(val, wdt->base);
+
+	spin_unlock(&wdt->lock);
+}
+
+static int max63xx_mmap_init(struct platform_device *p, struct max63xx_wdt *wdt)
+{
+	wdt->base = devm_platform_ioremap_resource(p, 0);
+	if (IS_ERR(wdt->base))
+		return PTR_ERR(wdt->base);
+
+	spin_lock_init(&wdt->lock);
+
+	wdt->ping = max63xx_mmap_ping;
+	wdt->set = max63xx_mmap_set;
+	return 0;
+}
+
+static int max63xx_wdt_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct max63xx_wdt *wdt;
+	const struct max63xx_timeout *table;
+	int err;
+
+	wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
+	if (!wdt)
+		return -ENOMEM;
+
+	/* Attempt to use fwnode first */
+	table = device_get_match_data(dev);
+	if (!table)
+		table = (struct max63xx_timeout *)pdev->id_entry->driver_data;
+
+	if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT)
+		heartbeat = DEFAULT_HEARTBEAT;
+
+	wdt->timeout = max63xx_select_timeout(table, heartbeat);
+	if (!wdt->timeout) {
+		dev_err(dev, "unable to satisfy %ds heartbeat request\n",
+			heartbeat);
+		return -EINVAL;
+	}
+
+	err = max63xx_mmap_init(pdev, wdt);
+	if (err)
+		return err;
+
+	platform_set_drvdata(pdev, &wdt->wdd);
+	watchdog_set_drvdata(&wdt->wdd, wdt);
+
+	wdt->wdd.parent = dev;
+	wdt->wdd.timeout = wdt->timeout->twd;
+	wdt->wdd.info = &max63xx_wdt_info;
+	wdt->wdd.ops = &max63xx_wdt_ops;
+
+	watchdog_set_nowayout(&wdt->wdd, nowayout);
+
+	err = devm_watchdog_register_device(dev, &wdt->wdd);
+	if (err)
+		return err;
+
+	dev_info(dev, "using %ds heartbeat with %ds initial delay\n",
+		 wdt->timeout->twd, wdt->timeout->tdelay);
+	return 0;
+}
+
+static const struct platform_device_id max63xx_id_table[] = {
+	{ "max6369_wdt", (kernel_ulong_t)max6369_table, },
+	{ "max6370_wdt", (kernel_ulong_t)max6369_table, },
+	{ "max6371_wdt", (kernel_ulong_t)max6371_table, },
+	{ "max6372_wdt", (kernel_ulong_t)max6371_table, },
+	{ "max6373_wdt", (kernel_ulong_t)max6373_table, },
+	{ "max6374_wdt", (kernel_ulong_t)max6373_table, },
+	{ },
+};
+MODULE_DEVICE_TABLE(platform, max63xx_id_table);
+
+static const struct of_device_id max63xx_dt_id_table[] = {
+	{ .compatible = "maxim,max6369", .data = max6369_table, },
+	{ .compatible = "maxim,max6370", .data = max6369_table, },
+	{ .compatible = "maxim,max6371", .data = max6371_table, },
+	{ .compatible = "maxim,max6372", .data = max6371_table, },
+	{ .compatible = "maxim,max6373", .data = max6373_table, },
+	{ .compatible = "maxim,max6374", .data = max6373_table, },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, max63xx_dt_id_table);
+
+static struct platform_driver max63xx_wdt_driver = {
+	.probe		= max63xx_wdt_probe,
+	.id_table	= max63xx_id_table,
+	.driver		= {
+		.name	= "max63xx_wdt",
+		.of_match_table = max63xx_dt_id_table,
+	},
+};
+
+module_platform_driver(max63xx_wdt_driver);
+
+MODULE_AUTHOR("Marc Zyngier <maz@misterjones.org>");
+MODULE_DESCRIPTION("max63xx Watchdog Driver");
+
+module_param(heartbeat, int, 0);
+MODULE_PARM_DESC(heartbeat,
+		 "Watchdog heartbeat period in seconds from 1 to "
+		 __MODULE_STRING(MAX_HEARTBEAT) ", default "
+		 __MODULE_STRING(DEFAULT_HEARTBEAT));
+
+module_param(nowayout, bool, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
+		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+module_param(nodelay, int, 0);
+MODULE_PARM_DESC(nodelay,
+		 "Force selection of a timeout setting without initial delay "
+		 "(max6373/74 only, default=0)");
+
+MODULE_LICENSE("GPL v2");