diff options
Diffstat (limited to 'drivers/watchdog/tangox_wdt.c')
| -rw-r--r-- | drivers/watchdog/tangox_wdt.c | 209 |
1 files changed, 209 insertions, 0 deletions
diff --git a/drivers/watchdog/tangox_wdt.c b/drivers/watchdog/tangox_wdt.c new file mode 100644 index 000000000..1afb0e9d8 --- /dev/null +++ b/drivers/watchdog/tangox_wdt.c @@ -0,0 +1,209 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Copyright (C) 2015 Mans Rullgard <mans@mansr.com> + * SMP86xx/SMP87xx Watchdog driver + */ + +#include <linux/bitops.h> +#include <linux/clk.h> +#include <linux/delay.h> +#include <linux/io.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/mod_devicetable.h> +#include <linux/platform_device.h> +#include <linux/watchdog.h> + +#define DEFAULT_TIMEOUT 30 + +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 int timeout; +module_param(timeout, int, 0); +MODULE_PARM_DESC(timeout, "Watchdog timeout"); + +/* + * Counter counts down from programmed value. Reset asserts when + * the counter reaches 1. + */ +#define WD_COUNTER 0 + +#define WD_CONFIG 4 +#define WD_CONFIG_XTAL_IN BIT(0) +#define WD_CONFIG_DISABLE BIT(31) + +struct tangox_wdt_device { + struct watchdog_device wdt; + void __iomem *base; + unsigned long clk_rate; + struct clk *clk; +}; + +static int tangox_wdt_set_timeout(struct watchdog_device *wdt, + unsigned int new_timeout) +{ + wdt->timeout = new_timeout; + + return 0; +} + +static int tangox_wdt_start(struct watchdog_device *wdt) +{ + struct tangox_wdt_device *dev = watchdog_get_drvdata(wdt); + u32 ticks; + + ticks = 1 + wdt->timeout * dev->clk_rate; + writel(ticks, dev->base + WD_COUNTER); + + return 0; +} + +static int tangox_wdt_stop(struct watchdog_device *wdt) +{ + struct tangox_wdt_device *dev = watchdog_get_drvdata(wdt); + + writel(0, dev->base + WD_COUNTER); + + return 0; +} + +static unsigned int tangox_wdt_get_timeleft(struct watchdog_device *wdt) +{ + struct tangox_wdt_device *dev = watchdog_get_drvdata(wdt); + u32 count; + + count = readl(dev->base + WD_COUNTER); + + if (!count) + return 0; + + return (count - 1) / dev->clk_rate; +} + +static const struct watchdog_info tangox_wdt_info = { + .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, + .identity = "tangox watchdog", +}; + +static int tangox_wdt_restart(struct watchdog_device *wdt, + unsigned long action, void *data) +{ + struct tangox_wdt_device *dev = watchdog_get_drvdata(wdt); + + writel(1, dev->base + WD_COUNTER); + + return 0; +} + +static const struct watchdog_ops tangox_wdt_ops = { + .start = tangox_wdt_start, + .stop = tangox_wdt_stop, + .set_timeout = tangox_wdt_set_timeout, + .get_timeleft = tangox_wdt_get_timeleft, + .restart = tangox_wdt_restart, +}; + +static void tangox_clk_disable_unprepare(void *data) +{ + clk_disable_unprepare(data); +} + +static int tangox_wdt_probe(struct platform_device *pdev) +{ + struct tangox_wdt_device *dev; + u32 config; + int err; + + dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL); + if (!dev) + return -ENOMEM; + + dev->base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(dev->base)) + return PTR_ERR(dev->base); + + dev->clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(dev->clk)) + return PTR_ERR(dev->clk); + + err = clk_prepare_enable(dev->clk); + if (err) + return err; + err = devm_add_action_or_reset(&pdev->dev, + tangox_clk_disable_unprepare, dev->clk); + if (err) + return err; + + dev->clk_rate = clk_get_rate(dev->clk); + if (!dev->clk_rate) + return -EINVAL; + + dev->wdt.parent = &pdev->dev; + dev->wdt.info = &tangox_wdt_info; + dev->wdt.ops = &tangox_wdt_ops; + dev->wdt.timeout = DEFAULT_TIMEOUT; + dev->wdt.min_timeout = 1; + dev->wdt.max_hw_heartbeat_ms = (U32_MAX - 1) / dev->clk_rate; + + watchdog_init_timeout(&dev->wdt, timeout, &pdev->dev); + watchdog_set_nowayout(&dev->wdt, nowayout); + watchdog_set_drvdata(&dev->wdt, dev); + + /* + * Deactivate counter if disable bit is set to avoid + * accidental reset. + */ + config = readl(dev->base + WD_CONFIG); + if (config & WD_CONFIG_DISABLE) + writel(0, dev->base + WD_COUNTER); + + writel(WD_CONFIG_XTAL_IN, dev->base + WD_CONFIG); + + /* + * Mark as active and restart with configured timeout if + * already running. + */ + if (readl(dev->base + WD_COUNTER)) { + set_bit(WDOG_HW_RUNNING, &dev->wdt.status); + tangox_wdt_start(&dev->wdt); + } + + watchdog_set_restart_priority(&dev->wdt, 128); + + watchdog_stop_on_unregister(&dev->wdt); + err = devm_watchdog_register_device(&pdev->dev, &dev->wdt); + if (err) + return err; + + platform_set_drvdata(pdev, dev); + + dev_info(&pdev->dev, "SMP86xx/SMP87xx watchdog registered\n"); + + return 0; +} + +static const struct of_device_id tangox_wdt_dt_ids[] = { + { .compatible = "sigma,smp8642-wdt" }, + { .compatible = "sigma,smp8759-wdt" }, + { } +}; +MODULE_DEVICE_TABLE(of, tangox_wdt_dt_ids); + +static struct platform_driver tangox_wdt_driver = { + .probe = tangox_wdt_probe, + .driver = { + .name = "tangox-wdt", + .of_match_table = tangox_wdt_dt_ids, + }, +}; + +module_platform_driver(tangox_wdt_driver); + +MODULE_AUTHOR("Mans Rullgard <mans@mansr.com>"); +MODULE_DESCRIPTION("SMP86xx/SMP87xx Watchdog driver"); +MODULE_LICENSE("GPL"); |