diff options
Diffstat (limited to 'drivers/watchdog/bcm7038_wdt.c')
| -rw-r--r-- | drivers/watchdog/bcm7038_wdt.c | 216 |
1 files changed, 216 insertions, 0 deletions
diff --git a/drivers/watchdog/bcm7038_wdt.c b/drivers/watchdog/bcm7038_wdt.c new file mode 100644 index 000000000..979caa18d --- /dev/null +++ b/drivers/watchdog/bcm7038_wdt.c @@ -0,0 +1,216 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Copyright (C) 2015 Broadcom Corporation + * + */ + +#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 const struct watchdog_info bcm7038_wdt_info = { + .identity = "Broadcom BCM7038 Watchdog Timer", + .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | + WDIOF_MAGICCLOSE +}; + +static const 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 void bcm7038_clk_disable_unprepare(void *data) +{ + clk_disable_unprepare(data); +} + +static int bcm7038_wdt_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct bcm7038_watchdog *wdt; + int err; + + wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL); + if (!wdt) + return -ENOMEM; + + platform_set_drvdata(pdev, wdt); + + wdt->base = devm_platform_ioremap_resource(pdev, 0); + 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)) { + err = clk_prepare_enable(wdt->clk); + if (err) + return err; + err = devm_add_action_or_reset(dev, + bcm7038_clk_disable_unprepare, + wdt->clk); + if (err) + return err; + 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); + + watchdog_stop_on_reboot(&wdt->wdd); + watchdog_stop_on_unregister(&wdt->wdd); + err = devm_watchdog_register_device(dev, &wdt->wdd); + if (err) + return err; + + dev_info(dev, "Registered BCM7038 Watchdog\n"); + + 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 const struct of_device_id bcm7038_wdt_match[] = { + { .compatible = "brcm,bcm7038-wdt" }, + {}, +}; +MODULE_DEVICE_TABLE(of, bcm7038_wdt_match); + +static struct platform_driver bcm7038_wdt_driver = { + .probe = bcm7038_wdt_probe, + .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"); +MODULE_DESCRIPTION("Driver for Broadcom 7038 SoCs Watchdog"); +MODULE_AUTHOR("Justin Chen"); |