1 files changed, 440 insertions, 0 deletions
diff --git a/drivers/watchdog/imx2_wdt.c b/drivers/watchdog/imx2_wdt.c
new file mode 100644
index 000000000..9f3123b04
--- /dev/null
+++ b/drivers/watchdog/imx2_wdt.c
@@ -0,0 +1,440 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Watchdog driver for IMX2 and later processors
+ *
+ *  Copyright (C) 2010 Wolfram Sang, Pengutronix e.K. <w.sang@pengutronix.de>
+ *  Copyright (C) 2014 Freescale Semiconductor, Inc.
+ *
+ * some parts adapted by similar drivers from Darius Augulis and Vladimir
+ * Zapolskiy, additional improvements by Wim Van Sebroeck.
+ *
+ * NOTE: MX1 has a slightly different Watchdog than MX2 and later:
+ *
+ *			MX1:		MX2+:
+ *			----		-----
+ * Registers:		32-bit		16-bit
+ * Stopable timer:	Yes		No
+ * Need to enable clk:	No		Yes
+ * Halt on suspend:	Manual		Can be automatic
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.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/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/watchdog.h>
+
+#define DRIVER_NAME "imx2-wdt"
+
+#define IMX2_WDT_WCR		0x00		/* Control Register */
+#define IMX2_WDT_WCR_WT		(0xFF << 8)	/* -> Watchdog Timeout Field */
+#define IMX2_WDT_WCR_WDA	BIT(5)		/* -> External Reset WDOG_B */
+#define IMX2_WDT_WCR_SRS	BIT(4)		/* -> Software Reset Signal */
+#define IMX2_WDT_WCR_WRE	BIT(3)		/* -> WDOG Reset Enable */
+#define IMX2_WDT_WCR_WDE	BIT(2)		/* -> Watchdog Enable */
+#define IMX2_WDT_WCR_WDZST	BIT(0)		/* -> Watchdog timer Suspend */
+
+#define IMX2_WDT_WSR		0x02		/* Service Register */
+#define IMX2_WDT_SEQ1		0x5555		/* -> service sequence 1 */
+#define IMX2_WDT_SEQ2		0xAAAA		/* -> service sequence 2 */
+
+#define IMX2_WDT_WRSR		0x04		/* Reset Status Register */
+#define IMX2_WDT_WRSR_TOUT	BIT(1)		/* -> Reset due to Timeout */
+
+#define IMX2_WDT_WICR		0x06		/* Interrupt Control Register */
+#define IMX2_WDT_WICR_WIE	BIT(15)		/* -> Interrupt Enable */
+#define IMX2_WDT_WICR_WTIS	BIT(14)		/* -> Interrupt Status */
+#define IMX2_WDT_WICR_WICT	0xFF		/* -> Interrupt Count Timeout */
+
+#define IMX2_WDT_WMCR		0x08		/* Misc Register */
+
+#define IMX2_WDT_MAX_TIME	128U
+#define IMX2_WDT_DEFAULT_TIME	60		/* in seconds */
+
+#define WDOG_SEC_TO_COUNT(s)	((s * 2 - 1) << 8)
+
+struct imx2_wdt_device {
+	struct clk *clk;
+	struct regmap *regmap;
+	struct watchdog_device wdog;
+	bool ext_reset;
+};
+
+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) ")");
+
+
+static unsigned timeout;
+module_param(timeout, uint, 0);
+MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default="
+				__MODULE_STRING(IMX2_WDT_DEFAULT_TIME) ")");
+
+static const struct watchdog_info imx2_wdt_info = {
+	.identity = "imx2+ watchdog",
+	.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
+};
+
+static const struct watchdog_info imx2_wdt_pretimeout_info = {
+	.identity = "imx2+ watchdog",
+	.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE |
+		   WDIOF_PRETIMEOUT,
+};
+
+static int imx2_wdt_restart(struct watchdog_device *wdog, unsigned long action,
+			    void *data)
+{
+	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
+	unsigned int wcr_enable = IMX2_WDT_WCR_WDE;
+
+	/* Use internal reset or external - not both */
+	if (wdev->ext_reset)
+		wcr_enable |= IMX2_WDT_WCR_SRS; /* do not assert int reset */
+	else
+		wcr_enable |= IMX2_WDT_WCR_WDA; /* do not assert ext-reset */
+
+	/* Assert SRS signal */
+	regmap_write(wdev->regmap, IMX2_WDT_WCR, wcr_enable);
+	/*
+	 * Due to imx6q errata ERR004346 (WDOG: WDOG SRS bit requires to be
+	 * written twice), we add another two writes to ensure there must be at
+	 * least two writes happen in the same one 32kHz clock period.  We save
+	 * the target check here, since the writes shouldn't be a huge burden
+	 * for other platforms.
+	 */
+	regmap_write(wdev->regmap, IMX2_WDT_WCR, wcr_enable);
+	regmap_write(wdev->regmap, IMX2_WDT_WCR, wcr_enable);
+
+	/* wait for reset to assert... */
+	mdelay(500);
+
+	return 0;
+}
+
+static inline void imx2_wdt_setup(struct watchdog_device *wdog)
+{
+	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
+	u32 val;
+
+	regmap_read(wdev->regmap, IMX2_WDT_WCR, &val);
+
+	/* Suspend timer in low power mode, write once-only */
+	val |= IMX2_WDT_WCR_WDZST;
+	/* Strip the old watchdog Time-Out value */
+	val &= ~IMX2_WDT_WCR_WT;
+	/* Generate internal chip-level reset if WDOG times out */
+	if (!wdev->ext_reset)
+		val &= ~IMX2_WDT_WCR_WRE;
+	/* Or if external-reset assert WDOG_B reset only on time-out */
+	else
+		val |= IMX2_WDT_WCR_WRE;
+	/* Keep Watchdog Disabled */
+	val &= ~IMX2_WDT_WCR_WDE;
+	/* Set the watchdog's Time-Out value */
+	val |= WDOG_SEC_TO_COUNT(wdog->timeout);
+
+	regmap_write(wdev->regmap, IMX2_WDT_WCR, val);
+
+	/* enable the watchdog */
+	val |= IMX2_WDT_WCR_WDE;
+	regmap_write(wdev->regmap, IMX2_WDT_WCR, val);
+}
+
+static inline bool imx2_wdt_is_running(struct imx2_wdt_device *wdev)
+{
+	u32 val;
+
+	regmap_read(wdev->regmap, IMX2_WDT_WCR, &val);
+
+	return val & IMX2_WDT_WCR_WDE;
+}
+
+static int imx2_wdt_ping(struct watchdog_device *wdog)
+{
+	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
+
+	regmap_write(wdev->regmap, IMX2_WDT_WSR, IMX2_WDT_SEQ1);
+	regmap_write(wdev->regmap, IMX2_WDT_WSR, IMX2_WDT_SEQ2);
+	return 0;
+}
+
+static void __imx2_wdt_set_timeout(struct watchdog_device *wdog,
+				   unsigned int new_timeout)
+{
+	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
+
+	regmap_update_bits(wdev->regmap, IMX2_WDT_WCR, IMX2_WDT_WCR_WT,
+			   WDOG_SEC_TO_COUNT(new_timeout));
+}
+
+static int imx2_wdt_set_timeout(struct watchdog_device *wdog,
+				unsigned int new_timeout)
+{
+	unsigned int actual;
+
+	actual = min(new_timeout, IMX2_WDT_MAX_TIME);
+	__imx2_wdt_set_timeout(wdog, actual);
+	wdog->timeout = new_timeout;
+	return 0;
+}
+
+static int imx2_wdt_set_pretimeout(struct watchdog_device *wdog,
+				   unsigned int new_pretimeout)
+{
+	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
+
+	if (new_pretimeout >= IMX2_WDT_MAX_TIME)
+		return -EINVAL;
+
+	wdog->pretimeout = new_pretimeout;
+
+	regmap_update_bits(wdev->regmap, IMX2_WDT_WICR,
+			   IMX2_WDT_WICR_WIE | IMX2_WDT_WICR_WICT,
+			   IMX2_WDT_WICR_WIE | (new_pretimeout << 1));
+	return 0;
+}
+
+static irqreturn_t imx2_wdt_isr(int irq, void *wdog_arg)
+{
+	struct watchdog_device *wdog = wdog_arg;
+	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
+
+	regmap_write_bits(wdev->regmap, IMX2_WDT_WICR,
+			  IMX2_WDT_WICR_WTIS, IMX2_WDT_WICR_WTIS);
+
+	watchdog_notify_pretimeout(wdog);
+
+	return IRQ_HANDLED;
+}
+
+static int imx2_wdt_start(struct watchdog_device *wdog)
+{
+	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
+
+	if (imx2_wdt_is_running(wdev))
+		imx2_wdt_set_timeout(wdog, wdog->timeout);
+	else
+		imx2_wdt_setup(wdog);
+
+	set_bit(WDOG_HW_RUNNING, &wdog->status);
+
+	return imx2_wdt_ping(wdog);
+}
+
+static const struct watchdog_ops imx2_wdt_ops = {
+	.owner = THIS_MODULE,
+	.start = imx2_wdt_start,
+	.ping = imx2_wdt_ping,
+	.set_timeout = imx2_wdt_set_timeout,
+	.set_pretimeout = imx2_wdt_set_pretimeout,
+	.restart = imx2_wdt_restart,
+};
+
+static const struct regmap_config imx2_wdt_regmap_config = {
+	.reg_bits = 16,
+	.reg_stride = 2,
+	.val_bits = 16,
+	.max_register = 0x8,
+};
+
+static int __init imx2_wdt_probe(struct platform_device *pdev)
+{
+	struct imx2_wdt_device *wdev;
+	struct watchdog_device *wdog;
+	struct resource *res;
+	void __iomem *base;
+	int ret;
+	u32 val;
+
+	wdev = devm_kzalloc(&pdev->dev, sizeof(*wdev), GFP_KERNEL);
+	if (!wdev)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	wdev->regmap = devm_regmap_init_mmio_clk(&pdev->dev, NULL, base,
+						 &imx2_wdt_regmap_config);
+	if (IS_ERR(wdev->regmap)) {
+		dev_err(&pdev->dev, "regmap init failed\n");
+		return PTR_ERR(wdev->regmap);
+	}
+
+	wdev->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(wdev->clk)) {
+		dev_err(&pdev->dev, "can't get Watchdog clock\n");
+		return PTR_ERR(wdev->clk);
+	}
+
+	wdog			= &wdev->wdog;
+	wdog->info		= &imx2_wdt_info;
+	wdog->ops		= &imx2_wdt_ops;
+	wdog->min_timeout	= 1;
+	wdog->timeout		= IMX2_WDT_DEFAULT_TIME;
+	wdog->max_hw_heartbeat_ms = IMX2_WDT_MAX_TIME * 1000;
+	wdog->parent		= &pdev->dev;
+
+	ret = platform_get_irq(pdev, 0);
+	if (ret > 0)
+		if (!devm_request_irq(&pdev->dev, ret, imx2_wdt_isr, 0,
+				      dev_name(&pdev->dev), wdog))
+			wdog->info = &imx2_wdt_pretimeout_info;
+
+	ret = clk_prepare_enable(wdev->clk);
+	if (ret)
+		return ret;
+
+	regmap_read(wdev->regmap, IMX2_WDT_WRSR, &val);
+	wdog->bootstatus = val & IMX2_WDT_WRSR_TOUT ? WDIOF_CARDRESET : 0;
+
+	wdev->ext_reset = of_property_read_bool(pdev->dev.of_node,
+						"fsl,ext-reset-output");
+	platform_set_drvdata(pdev, wdog);
+	watchdog_set_drvdata(wdog, wdev);
+	watchdog_set_nowayout(wdog, nowayout);
+	watchdog_set_restart_priority(wdog, 128);
+	watchdog_init_timeout(wdog, timeout, &pdev->dev);
+
+	if (imx2_wdt_is_running(wdev)) {
+		imx2_wdt_set_timeout(wdog, wdog->timeout);
+		set_bit(WDOG_HW_RUNNING, &wdog->status);
+	}
+
+	/*
+	 * Disable the watchdog power down counter at boot. Otherwise the power
+	 * down counter will pull down the #WDOG interrupt line for one clock
+	 * cycle.
+	 */
+	regmap_write(wdev->regmap, IMX2_WDT_WMCR, 0);
+
+	ret = watchdog_register_device(wdog);
+	if (ret) {
+		dev_err(&pdev->dev, "cannot register watchdog device\n");
+		goto disable_clk;
+	}
+
+	dev_info(&pdev->dev, "timeout %d sec (nowayout=%d)\n",
+		 wdog->timeout, nowayout);
+
+	return 0;
+
+disable_clk:
+	clk_disable_unprepare(wdev->clk);
+	return ret;
+}
+
+static int __exit imx2_wdt_remove(struct platform_device *pdev)
+{
+	struct watchdog_device *wdog = platform_get_drvdata(pdev);
+	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
+
+	watchdog_unregister_device(wdog);
+
+	if (imx2_wdt_is_running(wdev)) {
+		imx2_wdt_ping(wdog);
+		dev_crit(&pdev->dev, "Device removed: Expect reboot!\n");
+	}
+	return 0;
+}
+
+static void imx2_wdt_shutdown(struct platform_device *pdev)
+{
+	struct watchdog_device *wdog = platform_get_drvdata(pdev);
+	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
+
+	if (imx2_wdt_is_running(wdev)) {
+		/*
+		 * We are running, configure max timeout before reboot
+		 * will take place.
+		 */
+		imx2_wdt_set_timeout(wdog, IMX2_WDT_MAX_TIME);
+		imx2_wdt_ping(wdog);
+		dev_crit(&pdev->dev, "Device shutdown: Expect reboot!\n");
+	}
+}
+
+#ifdef CONFIG_PM_SLEEP
+/* Disable watchdog if it is active or non-active but still running */
+static int imx2_wdt_suspend(struct device *dev)
+{
+	struct watchdog_device *wdog = dev_get_drvdata(dev);
+	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
+
+	/* The watchdog IP block is running */
+	if (imx2_wdt_is_running(wdev)) {
+		/*
+		 * Don't update wdog->timeout, we'll restore the current value
+		 * during resume.
+		 */
+		__imx2_wdt_set_timeout(wdog, IMX2_WDT_MAX_TIME);
+		imx2_wdt_ping(wdog);
+	}
+
+	clk_disable_unprepare(wdev->clk);
+
+	return 0;
+}
+
+/* Enable watchdog and configure it if necessary */
+static int imx2_wdt_resume(struct device *dev)
+{
+	struct watchdog_device *wdog = dev_get_drvdata(dev);
+	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
+	int ret;
+
+	ret = clk_prepare_enable(wdev->clk);
+	if (ret)
+		return ret;
+
+	if (watchdog_active(wdog) && !imx2_wdt_is_running(wdev)) {
+		/*
+		 * If the watchdog is still active and resumes
+		 * from deep sleep state, need to restart the
+		 * watchdog again.
+		 */
+		imx2_wdt_setup(wdog);
+	}
+	if (imx2_wdt_is_running(wdev)) {
+		imx2_wdt_set_timeout(wdog, wdog->timeout);
+		imx2_wdt_ping(wdog);
+	}
+
+	return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(imx2_wdt_pm_ops, imx2_wdt_suspend,
+			 imx2_wdt_resume);
+
+static const struct of_device_id imx2_wdt_dt_ids[] = {
+	{ .compatible = "fsl,imx21-wdt", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, imx2_wdt_dt_ids);
+
+static struct platform_driver imx2_wdt_driver = {
+	.remove		= __exit_p(imx2_wdt_remove),
+	.shutdown	= imx2_wdt_shutdown,
+	.driver		= {
+		.name	= DRIVER_NAME,
+		.pm     = &imx2_wdt_pm_ops,
+		.of_match_table = imx2_wdt_dt_ids,
+	},
+};
+
+module_platform_driver_probe(imx2_wdt_driver, imx2_wdt_probe);
+
+MODULE_AUTHOR("Wolfram Sang");
+MODULE_DESCRIPTION("Watchdog driver for IMX2 and later");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:" DRIVER_NAME);