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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
commit57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch)
tree5e910f0e82173f4ef4f51111366a3f1299037a7b /drivers/watchdog/imx2_wdt.c
Initial import
Diffstat (limited to 'drivers/watchdog/imx2_wdt.c')
-rw-r--r--drivers/watchdog/imx2_wdt.c418
1 files changed, 418 insertions, 0 deletions
diff --git a/drivers/watchdog/imx2_wdt.c b/drivers/watchdog/imx2_wdt.c
new file mode 100644
index 000000000..5e6d808d3
--- /dev/null
+++ b/drivers/watchdog/imx2_wdt.c
@@ -0,0 +1,418 @@
+/*
+ * 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.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ * 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/io.h>
+#include <linux/jiffies.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/notifier.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/reboot.h>
+#include <linux/regmap.h>
+#include <linux/timer.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_WRE (1 << 3) /* -> WDOG Reset Enable */
+#define IMX2_WDT_WCR_WDE (1 << 2) /* -> Watchdog Enable */
+#define IMX2_WDT_WCR_WDZST (1 << 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 (1 << 1) /* -> Reset due to Timeout */
+
+#define IMX2_WDT_WMCR 0x08 /* Misc Register */
+
+#define IMX2_WDT_MAX_TIME 128
+#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 timer_list timer; /* Pings the watchdog when closed */
+ struct watchdog_device wdog;
+ struct notifier_block restart_handler;
+};
+
+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 = IMX2_WDT_DEFAULT_TIME;
+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 int imx2_restart_handler(struct notifier_block *this, unsigned long mode,
+ void *cmd)
+{
+ unsigned int wcr_enable = IMX2_WDT_WCR_WDE;
+ struct imx2_wdt_device *wdev = container_of(this,
+ struct imx2_wdt_device,
+ restart_handler);
+ /* Assert SRS signal */
+ regmap_write(wdev->regmap, 0, 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, 0, wcr_enable);
+ regmap_write(wdev->regmap, 0, wcr_enable);
+
+ /* wait for reset to assert... */
+ mdelay(500);
+
+ return NOTIFY_DONE;
+}
+
+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 reset if WDOG times out */
+ 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_timer_ping(unsigned long arg)
+{
+ struct watchdog_device *wdog = (struct watchdog_device *)arg;
+ struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
+
+ /* ping it every wdog->timeout / 2 seconds to prevent reboot */
+ imx2_wdt_ping(wdog);
+ mod_timer(&wdev->timer, jiffies + wdog->timeout * HZ / 2);
+}
+
+static int 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));
+ return 0;
+}
+
+static int imx2_wdt_start(struct watchdog_device *wdog)
+{
+ struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
+
+ if (imx2_wdt_is_running(wdev)) {
+ /* delete the timer that pings the watchdog after close */
+ del_timer_sync(&wdev->timer);
+ imx2_wdt_set_timeout(wdog, wdog->timeout);
+ } else
+ imx2_wdt_setup(wdog);
+
+ return imx2_wdt_ping(wdog);
+}
+
+static int imx2_wdt_stop(struct watchdog_device *wdog)
+{
+ /*
+ * We don't need a clk_disable, it cannot be disabled once started.
+ * We use a timer to ping the watchdog while /dev/watchdog is closed
+ */
+ imx2_wdt_timer_ping((unsigned long)wdog);
+ return 0;
+}
+
+static inline void imx2_wdt_ping_if_active(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);
+ imx2_wdt_timer_ping((unsigned long)wdog);
+ }
+}
+
+static const struct watchdog_ops imx2_wdt_ops = {
+ .owner = THIS_MODULE,
+ .start = imx2_wdt_start,
+ .stop = imx2_wdt_stop,
+ .ping = imx2_wdt_ping,
+ .set_timeout = imx2_wdt_set_timeout,
+};
+
+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->max_timeout = IMX2_WDT_MAX_TIME;
+
+ clk_prepare_enable(wdev->clk);
+
+ regmap_read(wdev->regmap, IMX2_WDT_WRSR, &val);
+ wdog->bootstatus = val & IMX2_WDT_WRSR_TOUT ? WDIOF_CARDRESET : 0;
+
+ wdog->timeout = clamp_t(unsigned, timeout, 1, IMX2_WDT_MAX_TIME);
+ if (wdog->timeout != timeout)
+ dev_warn(&pdev->dev, "Initial timeout out of range! Clamped from %u to %u\n",
+ timeout, wdog->timeout);
+
+ platform_set_drvdata(pdev, wdog);
+ watchdog_set_drvdata(wdog, wdev);
+ watchdog_set_nowayout(wdog, nowayout);
+ watchdog_init_timeout(wdog, timeout, &pdev->dev);
+
+ setup_timer(&wdev->timer, imx2_wdt_timer_ping, (unsigned long)wdog);
+
+ imx2_wdt_ping_if_active(wdog);
+
+ /*
+ * 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");
+ return ret;
+ }
+
+ wdev->restart_handler.notifier_call = imx2_restart_handler;
+ wdev->restart_handler.priority = 128;
+ ret = register_restart_handler(&wdev->restart_handler);
+ if (ret)
+ dev_err(&pdev->dev, "cannot register restart handler\n");
+
+ dev_info(&pdev->dev, "timeout %d sec (nowayout=%d)\n",
+ wdog->timeout, nowayout);
+
+ return 0;
+}
+
+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);
+
+ unregister_restart_handler(&wdev->restart_handler);
+
+ watchdog_unregister_device(wdog);
+
+ if (imx2_wdt_is_running(wdev)) {
+ del_timer_sync(&wdev->timer);
+ 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, we need to delete the timer but will
+ * give max timeout before reboot will take place
+ */
+ del_timer_sync(&wdev->timer);
+ 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)) {
+ imx2_wdt_set_timeout(wdog, IMX2_WDT_MAX_TIME);
+ imx2_wdt_ping(wdog);
+
+ /* The watchdog is not active */
+ if (!watchdog_active(wdog))
+ del_timer_sync(&wdev->timer);
+ }
+
+ 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);
+
+ clk_prepare_enable(wdev->clk);
+
+ 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);
+ imx2_wdt_set_timeout(wdog, wdog->timeout);
+ imx2_wdt_ping(wdog);
+ } else if (imx2_wdt_is_running(wdev)) {
+ /* Resuming from non-deep sleep state. */
+ imx2_wdt_set_timeout(wdog, wdog->timeout);
+ imx2_wdt_ping(wdog);
+ /*
+ * But the watchdog is not active, then start
+ * the timer again.
+ */
+ if (!watchdog_active(wdog))
+ mod_timer(&wdev->timer,
+ jiffies + wdog->timeout * HZ / 2);
+ }
+
+ 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);