--- /dev/null
+/*
+ * Copyright (C) 2015 Broadcom Corporation
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * 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/clk.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pm.h>
+#include <linux/watchdog.h>
+
+#define WDT_START_1 0xff00
+#define WDT_START_2 0x00ff
+#define WDT_STOP_1 0xee00
+#define WDT_STOP_2 0x00ee
+
+#define WDT_TIMEOUT_REG 0x0
+#define WDT_CMD_REG 0x4
+
+#define WDT_MIN_TIMEOUT 1 /* seconds */
+#define WDT_DEFAULT_TIMEOUT 30 /* seconds */
+#define WDT_DEFAULT_RATE 27000000
+
+struct bcm7038_watchdog {
+ void __iomem *base;
+ struct watchdog_device wdd;
+ u32 rate;
+ struct clk *clk;
+};
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+
+static void bcm7038_wdt_set_timeout_reg(struct watchdog_device *wdog)
+{
+ struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog);
+ u32 timeout;
+
+ timeout = wdt->rate * wdog->timeout;
+
+ writel(timeout, wdt->base + WDT_TIMEOUT_REG);
+}
+
+static int bcm7038_wdt_ping(struct watchdog_device *wdog)
+{
+ struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog);
+
+ writel(WDT_START_1, wdt->base + WDT_CMD_REG);
+ writel(WDT_START_2, wdt->base + WDT_CMD_REG);
+
+ return 0;
+}
+
+static int bcm7038_wdt_start(struct watchdog_device *wdog)
+{
+ bcm7038_wdt_set_timeout_reg(wdog);
+ bcm7038_wdt_ping(wdog);
+
+ return 0;
+}
+
+static int bcm7038_wdt_stop(struct watchdog_device *wdog)
+{
+ struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog);
+
+ writel(WDT_STOP_1, wdt->base + WDT_CMD_REG);
+ writel(WDT_STOP_2, wdt->base + WDT_CMD_REG);
+
+ return 0;
+}
+
+static int bcm7038_wdt_set_timeout(struct watchdog_device *wdog,
+ unsigned int t)
+{
+ /* Can't modify timeout value if watchdog timer is running */
+ bcm7038_wdt_stop(wdog);
+ wdog->timeout = t;
+ bcm7038_wdt_start(wdog);
+
+ return 0;
+}
+
+static unsigned int bcm7038_wdt_get_timeleft(struct watchdog_device *wdog)
+{
+ struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog);
+ u32 time_left;
+
+ time_left = readl(wdt->base + WDT_CMD_REG);
+
+ return time_left / wdt->rate;
+}
+
+static struct watchdog_info bcm7038_wdt_info = {
+ .identity = "Broadcom BCM7038 Watchdog Timer",
+ .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
+ WDIOF_MAGICCLOSE
+};
+
+static struct watchdog_ops bcm7038_wdt_ops = {
+ .owner = THIS_MODULE,
+ .start = bcm7038_wdt_start,
+ .stop = bcm7038_wdt_stop,
+ .set_timeout = bcm7038_wdt_set_timeout,
+ .get_timeleft = bcm7038_wdt_get_timeleft,
+};
+
+static int bcm7038_wdt_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct bcm7038_watchdog *wdt;
+ struct resource *res;
+ int err;
+
+ wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
+ if (!wdt)
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, wdt);
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ wdt->base = devm_ioremap_resource(dev, res);
+ if (IS_ERR(wdt->base))
+ return PTR_ERR(wdt->base);
+
+ wdt->clk = devm_clk_get(dev, NULL);
+ /* If unable to get clock, use default frequency */
+ if (!IS_ERR(wdt->clk)) {
+ clk_prepare_enable(wdt->clk);
+ wdt->rate = clk_get_rate(wdt->clk);
+ /* Prevent divide-by-zero exception */
+ if (!wdt->rate)
+ wdt->rate = WDT_DEFAULT_RATE;
+ } else {
+ wdt->rate = WDT_DEFAULT_RATE;
+ wdt->clk = NULL;
+ }
+
+ wdt->wdd.info = &bcm7038_wdt_info;
+ wdt->wdd.ops = &bcm7038_wdt_ops;
+ wdt->wdd.min_timeout = WDT_MIN_TIMEOUT;
+ wdt->wdd.timeout = WDT_DEFAULT_TIMEOUT;
+ wdt->wdd.max_timeout = 0xffffffff / wdt->rate;
+ wdt->wdd.parent = dev;
+ watchdog_set_drvdata(&wdt->wdd, wdt);
+
+ err = watchdog_register_device(&wdt->wdd);
+ if (err) {
+ dev_err(dev, "Failed to register watchdog device\n");
+ clk_disable_unprepare(wdt->clk);
+ return err;
+ }
+
+ dev_info(dev, "Registered BCM7038 Watchdog\n");
+
+ return 0;
+}
+
+static int bcm7038_wdt_remove(struct platform_device *pdev)
+{
+ struct bcm7038_watchdog *wdt = platform_get_drvdata(pdev);
+
+ if (!nowayout)
+ bcm7038_wdt_stop(&wdt->wdd);
+
+ watchdog_unregister_device(&wdt->wdd);
+ clk_disable_unprepare(wdt->clk);
+
+ return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int bcm7038_wdt_suspend(struct device *dev)
+{
+ struct bcm7038_watchdog *wdt = dev_get_drvdata(dev);
+
+ if (watchdog_active(&wdt->wdd))
+ return bcm7038_wdt_stop(&wdt->wdd);
+
+ return 0;
+}
+
+static int bcm7038_wdt_resume(struct device *dev)
+{
+ struct bcm7038_watchdog *wdt = dev_get_drvdata(dev);
+
+ if (watchdog_active(&wdt->wdd))
+ return bcm7038_wdt_start(&wdt->wdd);
+
+ return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(bcm7038_wdt_pm_ops, bcm7038_wdt_suspend,
+ bcm7038_wdt_resume);
+
+static void bcm7038_wdt_shutdown(struct platform_device *pdev)
+{
+ struct bcm7038_watchdog *wdt = platform_get_drvdata(pdev);
+
+ if (watchdog_active(&wdt->wdd))
+ bcm7038_wdt_stop(&wdt->wdd);
+}
+
+static const struct of_device_id bcm7038_wdt_match[] = {
+ { .compatible = "brcm,bcm7038-wdt" },
+ {},
+};
+
+static struct platform_driver bcm7038_wdt_driver = {
+ .probe = bcm7038_wdt_probe,
+ .remove = bcm7038_wdt_remove,
+ .shutdown = bcm7038_wdt_shutdown,
+ .driver = {
+ .name = "bcm7038-wdt",
+ .of_match_table = bcm7038_wdt_match,
+ .pm = &bcm7038_wdt_pm_ops,
+ }
+};
+module_platform_driver(bcm7038_wdt_driver);
+
+module_param(nowayout, bool, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
+ __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Driver for Broadcom 7038 SoCs Watchdog");
+MODULE_AUTHOR("Justin Chen");
Code Review / kvmfornfv.git / blobdiff