1 files changed, 417 insertions, 0 deletions

diff --git a/drivers/watchdog/at91sam9_wdt.c b/drivers/watchdog/at91sam9_wdt.c
new file mode 100644
index 000000000..fed7be246
--- /dev/null
+++ b/drivers/watchdog/at91sam9_wdt.c
@@ -0,0 +1,417 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Watchdog driver for Atmel AT91SAM9x processors.
+ *
+ * Copyright (C) 2008 Renaud CERRATO r.cerrato@til-technologies.fr
+ *
+ */
+
+/*
+ * The Watchdog Timer Mode Register can be only written to once. If the
+ * timeout need to be set from Linux, be sure that the bootstrap or the
+ * bootloader doesn't write to this register.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/clk.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/platform_device.h>
+#include <linux/reboot.h>
+#include <linux/types.h>
+#include <linux/watchdog.h>
+#include <linux/jiffies.h>
+#include <linux/timer.h>
+#include <linux/bitops.h>
+#include <linux/uaccess.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+
+#include "at91sam9_wdt.h"
+
+#define DRV_NAME "AT91SAM9 Watchdog"
+
+#define wdt_read(wdt, field) \
+	readl_relaxed((wdt)->base + (field))
+#define wdt_write(wtd, field, val) \
+	writel_relaxed((val), (wdt)->base + (field))
+
+/* AT91SAM9 watchdog runs a 12bit counter @ 256Hz,
+ * use this to convert a watchdog
+ * value from/to milliseconds.
+ */
+#define ticks_to_hz_rounddown(t)	((((t) + 1) * HZ) >> 8)
+#define ticks_to_hz_roundup(t)		(((((t) + 1) * HZ) + 255) >> 8)
+#define ticks_to_secs(t)		(((t) + 1) >> 8)
+#define secs_to_ticks(s)		((s) ? (((s) << 8) - 1) : 0)
+
+#define WDT_MR_RESET	0x3FFF2FFF
+
+/* Watchdog max counter value in ticks */
+#define WDT_COUNTER_MAX_TICKS	0xFFF
+
+/* Watchdog max delta/value in secs */
+#define WDT_COUNTER_MAX_SECS	ticks_to_secs(WDT_COUNTER_MAX_TICKS)
+
+/* Hardware timeout in seconds */
+#define WDT_HW_TIMEOUT 2
+
+/* Timer heartbeat (500ms) */
+#define WDT_TIMEOUT	(HZ/2)
+
+/* User land timeout */
+#define WDT_HEARTBEAT 15
+static int heartbeat;
+module_param(heartbeat, int, 0);
+MODULE_PARM_DESC(heartbeat, "Watchdog heartbeats in seconds. "
+	"(default = " __MODULE_STRING(WDT_HEARTBEAT) ")");
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, bool, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
+	"(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+#define to_wdt(wdd) container_of(wdd, struct at91wdt, wdd)
+struct at91wdt {
+	struct watchdog_device wdd;
+	void __iomem *base;
+	unsigned long next_heartbeat;	/* the next_heartbeat for the timer */
+	struct timer_list timer;	/* The timer that pings the watchdog */
+	u32 mr;
+	u32 mr_mask;
+	unsigned long heartbeat;	/* WDT heartbeat in jiffies */
+	bool nowayout;
+	unsigned int irq;
+	struct clk *sclk;
+};
+
+/* ......................................................................... */
+
+static irqreturn_t wdt_interrupt(int irq, void *dev_id)
+{
+	struct at91wdt *wdt = (struct at91wdt *)dev_id;
+
+	if (wdt_read(wdt, AT91_WDT_SR)) {
+		pr_crit("at91sam9 WDT software reset\n");
+		emergency_restart();
+		pr_crit("Reboot didn't ?????\n");
+	}
+
+	return IRQ_HANDLED;
+}
+
+/*
+ * Reload the watchdog timer.  (ie, pat the watchdog)
+ */
+static inline void at91_wdt_reset(struct at91wdt *wdt)
+{
+	wdt_write(wdt, AT91_WDT_CR, AT91_WDT_KEY | AT91_WDT_WDRSTT);
+}
+
+/*
+ * Timer tick
+ */
+static void at91_ping(struct timer_list *t)
+{
+	struct at91wdt *wdt = from_timer(wdt, t, timer);
+	if (time_before(jiffies, wdt->next_heartbeat) ||
+	    !watchdog_active(&wdt->wdd)) {
+		at91_wdt_reset(wdt);
+		mod_timer(&wdt->timer, jiffies + wdt->heartbeat);
+	} else {
+		pr_crit("I will reset your machine !\n");
+	}
+}
+
+static int at91_wdt_start(struct watchdog_device *wdd)
+{
+	struct at91wdt *wdt = to_wdt(wdd);
+	/* calculate when the next userspace timeout will be */
+	wdt->next_heartbeat = jiffies + wdd->timeout * HZ;
+	return 0;
+}
+
+static int at91_wdt_stop(struct watchdog_device *wdd)
+{
+	/* The watchdog timer hardware can not be stopped... */
+	return 0;
+}
+
+static int at91_wdt_set_timeout(struct watchdog_device *wdd, unsigned int new_timeout)
+{
+	wdd->timeout = new_timeout;
+	return at91_wdt_start(wdd);
+}
+
+static int at91_wdt_init(struct platform_device *pdev, struct at91wdt *wdt)
+{
+	u32 tmp;
+	u32 delta;
+	u32 value;
+	int err;
+	u32 mask = wdt->mr_mask;
+	unsigned long min_heartbeat = 1;
+	unsigned long max_heartbeat;
+	struct device *dev = &pdev->dev;
+
+	tmp = wdt_read(wdt, AT91_WDT_MR);
+	if ((tmp & mask) != (wdt->mr & mask)) {
+		if (tmp == WDT_MR_RESET) {
+			wdt_write(wdt, AT91_WDT_MR, wdt->mr);
+			tmp = wdt_read(wdt, AT91_WDT_MR);
+		}
+	}
+
+	if (tmp & AT91_WDT_WDDIS) {
+		if (wdt->mr & AT91_WDT_WDDIS)
+			return 0;
+		dev_err(dev, "watchdog is disabled\n");
+		return -EINVAL;
+	}
+
+	value = tmp & AT91_WDT_WDV;
+	delta = (tmp & AT91_WDT_WDD) >> 16;
+
+	if (delta < value)
+		min_heartbeat = ticks_to_hz_roundup(value - delta);
+
+	max_heartbeat = ticks_to_hz_rounddown(value);
+	if (!max_heartbeat) {
+		dev_err(dev,
+			"heartbeat is too small for the system to handle it correctly\n");
+		return -EINVAL;
+	}
+
+	/*
+	 * Try to reset the watchdog counter 4 or 2 times more often than
+	 * actually requested, to avoid spurious watchdog reset.
+	 * If this is not possible because of the min_heartbeat value, reset
+	 * it at the min_heartbeat period.
+	 */
+	if ((max_heartbeat / 4) >= min_heartbeat)
+		wdt->heartbeat = max_heartbeat / 4;
+	else if ((max_heartbeat / 2) >= min_heartbeat)
+		wdt->heartbeat = max_heartbeat / 2;
+	else
+		wdt->heartbeat = min_heartbeat;
+
+	if (max_heartbeat < min_heartbeat + 4)
+		dev_warn(dev,
+			 "min heartbeat and max heartbeat might be too close for the system to handle it correctly\n");
+
+	if ((tmp & AT91_WDT_WDFIEN) && wdt->irq) {
+		err = devm_request_irq(dev, wdt->irq, wdt_interrupt,
+				       IRQF_SHARED | IRQF_IRQPOLL | IRQF_NO_SUSPEND,
+				       pdev->name, wdt);
+		if (err)
+			return err;
+	}
+
+	if ((tmp & wdt->mr_mask) != (wdt->mr & wdt->mr_mask))
+		dev_warn(dev,
+			 "watchdog already configured differently (mr = %x expecting %x)\n",
+			 tmp & wdt->mr_mask, wdt->mr & wdt->mr_mask);
+
+	timer_setup(&wdt->timer, at91_ping, 0);
+
+	/*
+	 * Use min_heartbeat the first time to avoid spurious watchdog reset:
+	 * we don't know for how long the watchdog counter is running, and
+	 *  - resetting it right now might trigger a watchdog fault reset
+	 *  - waiting for heartbeat time might lead to a watchdog timeout
+	 *    reset
+	 */
+	mod_timer(&wdt->timer, jiffies + min_heartbeat);
+
+	/* Try to set timeout from device tree first */
+	if (watchdog_init_timeout(&wdt->wdd, 0, dev))
+		watchdog_init_timeout(&wdt->wdd, heartbeat, dev);
+	watchdog_set_nowayout(&wdt->wdd, wdt->nowayout);
+	err = watchdog_register_device(&wdt->wdd);
+	if (err)
+		goto out_stop_timer;
+
+	wdt->next_heartbeat = jiffies + wdt->wdd.timeout * HZ;
+
+	return 0;
+
+out_stop_timer:
+	del_timer(&wdt->timer);
+	return err;
+}
+
+/* ......................................................................... */
+
+static const struct watchdog_info at91_wdt_info = {
+	.identity	= DRV_NAME,
+	.options	= WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
+						WDIOF_MAGICCLOSE,
+};
+
+static const struct watchdog_ops at91_wdt_ops = {
+	.owner =	THIS_MODULE,
+	.start =	at91_wdt_start,
+	.stop =		at91_wdt_stop,
+	.set_timeout =	at91_wdt_set_timeout,
+};
+
+#if defined(CONFIG_OF)
+static int of_at91wdt_init(struct device_node *np, struct at91wdt *wdt)
+{
+	u32 min = 0;
+	u32 max = WDT_COUNTER_MAX_SECS;
+	const char *tmp;
+
+	/* Get the interrupts property */
+	wdt->irq = irq_of_parse_and_map(np, 0);
+	if (!wdt->irq)
+		dev_warn(wdt->wdd.parent, "failed to get IRQ from DT\n");
+
+	if (!of_property_read_u32_index(np, "atmel,max-heartbeat-sec", 0,
+					&max)) {
+		if (!max || max > WDT_COUNTER_MAX_SECS)
+			max = WDT_COUNTER_MAX_SECS;
+
+		if (!of_property_read_u32_index(np, "atmel,min-heartbeat-sec",
+						0, &min)) {
+			if (min >= max)
+				min = max - 1;
+		}
+	}
+
+	min = secs_to_ticks(min);
+	max = secs_to_ticks(max);
+
+	wdt->mr_mask = 0x3FFFFFFF;
+	wdt->mr = 0;
+	if (!of_property_read_string(np, "atmel,watchdog-type", &tmp) &&
+	    !strcmp(tmp, "software")) {
+		wdt->mr |= AT91_WDT_WDFIEN;
+		wdt->mr_mask &= ~AT91_WDT_WDRPROC;
+	} else {
+		wdt->mr |= AT91_WDT_WDRSTEN;
+	}
+
+	if (!of_property_read_string(np, "atmel,reset-type", &tmp) &&
+	    !strcmp(tmp, "proc"))
+		wdt->mr |= AT91_WDT_WDRPROC;
+
+	if (of_property_read_bool(np, "atmel,disable")) {
+		wdt->mr |= AT91_WDT_WDDIS;
+		wdt->mr_mask &= AT91_WDT_WDDIS;
+	}
+
+	if (of_property_read_bool(np, "atmel,idle-halt"))
+		wdt->mr |= AT91_WDT_WDIDLEHLT;
+
+	if (of_property_read_bool(np, "atmel,dbg-halt"))
+		wdt->mr |= AT91_WDT_WDDBGHLT;
+
+	wdt->mr |= max | ((max - min) << 16);
+
+	return 0;
+}
+#else
+static inline int of_at91wdt_init(struct device_node *np, struct at91wdt *wdt)
+{
+	return 0;
+}
+#endif
+
+static int __init at91wdt_probe(struct platform_device *pdev)
+{
+	int err;
+	struct at91wdt *wdt;
+
+	wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
+	if (!wdt)
+		return -ENOMEM;
+
+	wdt->mr = (WDT_HW_TIMEOUT * 256) | AT91_WDT_WDRSTEN | AT91_WDT_WDD |
+		  AT91_WDT_WDDBGHLT | AT91_WDT_WDIDLEHLT;
+	wdt->mr_mask = 0x3FFFFFFF;
+	wdt->nowayout = nowayout;
+	wdt->wdd.parent = &pdev->dev;
+	wdt->wdd.info = &at91_wdt_info;
+	wdt->wdd.ops = &at91_wdt_ops;
+	wdt->wdd.timeout = WDT_HEARTBEAT;
+	wdt->wdd.min_timeout = 1;
+	wdt->wdd.max_timeout = 0xFFFF;
+
+	wdt->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(wdt->base))
+		return PTR_ERR(wdt->base);
+
+	wdt->sclk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(wdt->sclk))
+		return PTR_ERR(wdt->sclk);
+
+	err = clk_prepare_enable(wdt->sclk);
+	if (err) {
+		dev_err(&pdev->dev, "Could not enable slow clock\n");
+		return err;
+	}
+
+	if (pdev->dev.of_node) {
+		err = of_at91wdt_init(pdev->dev.of_node, wdt);
+		if (err)
+			goto err_clk;
+	}
+
+	err = at91_wdt_init(pdev, wdt);
+	if (err)
+		goto err_clk;
+
+	platform_set_drvdata(pdev, wdt);
+
+	pr_info("enabled (heartbeat=%d sec, nowayout=%d)\n",
+		wdt->wdd.timeout, wdt->nowayout);
+
+	return 0;
+
+err_clk:
+	clk_disable_unprepare(wdt->sclk);
+
+	return err;
+}
+
+static int __exit at91wdt_remove(struct platform_device *pdev)
+{
+	struct at91wdt *wdt = platform_get_drvdata(pdev);
+	watchdog_unregister_device(&wdt->wdd);
+
+	pr_warn("I quit now, hardware will probably reboot!\n");
+	del_timer(&wdt->timer);
+	clk_disable_unprepare(wdt->sclk);
+
+	return 0;
+}
+
+#if defined(CONFIG_OF)
+static const struct of_device_id at91_wdt_dt_ids[] = {
+	{ .compatible = "atmel,at91sam9260-wdt" },
+	{ /* sentinel */ }
+};
+
+MODULE_DEVICE_TABLE(of, at91_wdt_dt_ids);
+#endif
+
+static struct platform_driver at91wdt_driver = {
+	.remove		= __exit_p(at91wdt_remove),
+	.driver		= {
+		.name	= "at91_wdt",
+		.of_match_table = of_match_ptr(at91_wdt_dt_ids),
+	},
+};
+
+module_platform_driver_probe(at91wdt_driver, at91wdt_probe);
+
+MODULE_AUTHOR("Renaud CERRATO <r.cerrato@til-technologies.fr>");
+MODULE_DESCRIPTION("Watchdog driver for Atmel AT91SAM9x processors");
+MODULE_LICENSE("GPL");