@@ -0,0 +1,268 @@
+/*
+ * Watchdog driver for the UniPhier watchdog timer
+ *
+ * (c) Copyright 2014 Panasonic Corporation
+ * (c) Copyright 2016 Socionext Inc.
+ * All rights reserved.
+ *
+ * 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.
+ *
+ * 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 <linux/bitops.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/watchdog.h>
+
+/* WDT timer setting register */
+#define WDTTIMSET 0x3004
+#define WDTTIMSET_PERIOD_MASK (0xf << 0)
+#define WDTTIMSET_PERIOD_1_SEC (0x3 << 0)
+
+/* WDT reset selection register */
+#define WDTRSTSEL 0x3008
+#define WDTRSTSEL_RSTSEL_MASK (0x3 << 0)
+#define WDTRSTSEL_RSTSEL_BOTH (0x0 << 0)
+#define WDTRSTSEL_RSTSEL_IRQ_ONLY (0x2 << 0)
+
+/* WDT control register */
+#define WDTCTRL 0x300c
+#define WDTCTRL_STATUS BIT(8)
+#define WDTCTRL_CLEAR BIT(1)
+#define WDTCTRL_ENABLE BIT(0)
+
+#define SEC_TO_WDTTIMSET_PRD(sec) \
+ (ilog2(sec) + WDTTIMSET_PERIOD_1_SEC)
+
+#define WDTST_TIMEOUT 1000 /* usec */
+
+#define WDT_DEFAULT_TIMEOUT 64 /* Default is 64 seconds */
+#define WDT_PERIOD_MIN 1
+#define WDT_PERIOD_MAX 128
+
+static unsigned int timeout = 0;
+static bool nowayout = WATCHDOG_NOWAYOUT;
+
+struct uniphier_wdt_dev {
+ struct watchdog_device wdt_dev;
+ struct regmap *regmap;
+};
+
+/*
+ * UniPhier Watchdog operations
+ */
+static int uniphier_watchdog_ping(struct watchdog_device *w)
+{
+ struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w);
+ unsigned int val;
+ int ret;
+
+ /* Clear counter */
+ ret = regmap_write_bits(wdev->regmap, WDTCTRL,
+ WDTCTRL_CLEAR, WDTCTRL_CLEAR);
+ if (!ret)
+ /*
+ * As SoC specification, after clear counter,
+ * it needs to wait until counter status is 1.
+ */
+ ret = regmap_read_poll_timeout(wdev->regmap, WDTCTRL, val,
+ (val & WDTCTRL_STATUS),
+ 0, WDTST_TIMEOUT);
+
+ return ret;
+}
+
+static int __uniphier_watchdog_start(struct regmap *regmap, unsigned int sec)
+{
+ unsigned int val;
+ int ret;
+
+ ret = regmap_read_poll_timeout(regmap, WDTCTRL, val,
+ !(val & WDTCTRL_STATUS),
+ 0, WDTST_TIMEOUT);
+ if (ret)
+ return ret;
+
+ /* Setup period */
+ ret = regmap_write(regmap, WDTTIMSET,
+ SEC_TO_WDTTIMSET_PRD(sec));
+ if (ret)
+ return ret;
+
+ /* Enable and clear watchdog */
+ ret = regmap_write(regmap, WDTCTRL, WDTCTRL_ENABLE | WDTCTRL_CLEAR);
+ if (!ret)
+ /*
+ * As SoC specification, after clear counter,
+ * it needs to wait until counter status is 1.
+ */
+ ret = regmap_read_poll_timeout(regmap, WDTCTRL, val,
+ (val & WDTCTRL_STATUS),
+ 0, WDTST_TIMEOUT);
+
+ return ret;
+}
+
+static int __uniphier_watchdog_stop(struct regmap *regmap)
+{
+ /* Disable and stop watchdog */
+ return regmap_write_bits(regmap, WDTCTRL, WDTCTRL_ENABLE, 0);
+}
+
+static int __uniphier_watchdog_restart(struct regmap *regmap, unsigned int sec)
+{
+ int ret;
+
+ ret = __uniphier_watchdog_stop(regmap);
+ if (ret)
+ return ret;
+
+ return __uniphier_watchdog_start(regmap, sec);
+}
+
+static int uniphier_watchdog_start(struct watchdog_device *w)
+{
+ struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w);
+ unsigned int tmp_timeout;
+
+ tmp_timeout = roundup_pow_of_two(w->timeout);
+
+ return __uniphier_watchdog_start(wdev->regmap, tmp_timeout);
+}
+
+static int uniphier_watchdog_stop(struct watchdog_device *w)
+{
+ struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w);
+
+ return __uniphier_watchdog_stop(wdev->regmap);
+}
+
+static int uniphier_watchdog_set_timeout(struct watchdog_device *w,
+ unsigned int t)
+{
+ struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w);
+ unsigned int tmp_timeout;
+ int ret;
+
+ tmp_timeout = roundup_pow_of_two(t);
+ if (tmp_timeout == w->timeout)
+ return 0;
+
+ if (watchdog_active(w)) {
+ ret = __uniphier_watchdog_restart(wdev->regmap, tmp_timeout);
+ if (ret)
+ return ret;
+ }
+
+ w->timeout = tmp_timeout;
+
+ return 0;
+}
+
+/*
+ * Kernel Interfaces
+ */
+static const struct watchdog_info uniphier_wdt_info = {
+ .identity = "uniphier-wdt",
+ .options = WDIOF_SETTIMEOUT |
+ WDIOF_KEEPALIVEPING |
+ WDIOF_MAGICCLOSE |
+ WDIOF_OVERHEAT,
+};
+
+static const struct watchdog_ops uniphier_wdt_ops = {
+ .owner = THIS_MODULE,
+ .start = uniphier_watchdog_start,
+ .stop = uniphier_watchdog_stop,
+ .ping = uniphier_watchdog_ping,
+ .set_timeout = uniphier_watchdog_set_timeout,
+};
+
+static int uniphier_wdt_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct uniphier_wdt_dev *wdev;
+ struct regmap *regmap;
+ struct device_node *parent;
+ int ret;
+
+ wdev = devm_kzalloc(dev, sizeof(*wdev), GFP_KERNEL);
+ if (!wdev)
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, wdev);
+
+ parent = of_get_parent(dev->of_node); /* parent should be syscon node */
+ regmap = syscon_node_to_regmap(parent);
+ of_node_put(parent);
+ if (IS_ERR(regmap))
+ return PTR_ERR(regmap);
+
+ wdev->regmap = regmap;
+ wdev->wdt_dev.info = &uniphier_wdt_info;
+ wdev->wdt_dev.ops = &uniphier_wdt_ops;
+ wdev->wdt_dev.max_timeout = WDT_PERIOD_MAX;
+ wdev->wdt_dev.min_timeout = WDT_PERIOD_MIN;
+ wdev->wdt_dev.parent = dev;
+
+ if (watchdog_init_timeout(&wdev->wdt_dev, timeout, dev) < 0) {
+ wdev->wdt_dev.timeout = WDT_DEFAULT_TIMEOUT;
+ }
+ watchdog_set_nowayout(&wdev->wdt_dev, nowayout);
+ watchdog_stop_on_reboot(&wdev->wdt_dev);
+
+ watchdog_set_drvdata(&wdev->wdt_dev, wdev);
+
+ uniphier_watchdog_stop(&wdev->wdt_dev);
+ ret = regmap_write(wdev->regmap, WDTRSTSEL, WDTRSTSEL_RSTSEL_BOTH);
+ if (ret)
+ return ret;
+
+ ret = devm_watchdog_register_device(dev, &wdev->wdt_dev);
+ if (ret)
+ return ret;
+
+ dev_info(dev, "watchdog driver (timeout=%d sec, nowayout=%d)\n",
+ wdev->wdt_dev.timeout, nowayout);
+
+ return 0;
+}
+
+static const struct of_device_id uniphier_wdt_dt_ids[] = {
+ { .compatible = "socionext,uniphier-wdt" },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, uniphier_wdt_dt_ids);
+
+static struct platform_driver uniphier_wdt_driver = {
+ .probe = uniphier_wdt_probe,
+ .driver = {
+ .name = "uniphier-wdt",
+ .of_match_table = uniphier_wdt_dt_ids,
+ },
+};
+
+module_platform_driver(uniphier_wdt_driver);
+
+module_param(timeout, uint, 0000);
+MODULE_PARM_DESC(timeout,
+ "Watchdog timeout seconds in power of 2. (0 < timeout < 128, default="
+ __MODULE_STRING(WDT_DEFAULT_TIMEOUT) ")");
+
+module_param(nowayout, bool, 0000);
+MODULE_PARM_DESC(nowayout,
+ "Watchdog cannot be stopped once started (default="
+ __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+MODULE_AUTHOR("Keiji Hayashibara <hayashibara.keiji@socionext.com>");
+MODULE_DESCRIPTION("UniPhier Watchdog Device Driver");
+MODULE_LICENSE("GPL v2");