diff options
Diffstat (limited to 'drivers/watchdog/atlas7_wdt.c')
| -rw-r--r-- | drivers/watchdog/atlas7_wdt.c | 247 |
1 files changed, 247 insertions, 0 deletions
diff --git a/drivers/watchdog/atlas7_wdt.c b/drivers/watchdog/atlas7_wdt.c new file mode 100644 index 000000000..4abdcabd8 --- /dev/null +++ b/drivers/watchdog/atlas7_wdt.c @@ -0,0 +1,247 @@ +/* + * Watchdog driver for CSR Atlas7 + * + * Copyright (c) 2015 Cambridge Silicon Radio Limited, a CSR plc group company. + * + * Licensed under GPLv2. + */ + +#include <linux/clk.h> +#include <linux/io.h> +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/watchdog.h> + +#define ATLAS7_TIMER_WDT_INDEX 5 +#define ATLAS7_WDT_DEFAULT_TIMEOUT 20 + +#define ATLAS7_WDT_CNT_CTRL (0 + 4 * ATLAS7_TIMER_WDT_INDEX) +#define ATLAS7_WDT_CNT_MATCH (0x18 + 4 * ATLAS7_TIMER_WDT_INDEX) +#define ATLAS7_WDT_CNT (0x48 + 4 * ATLAS7_TIMER_WDT_INDEX) +#define ATLAS7_WDT_CNT_EN (BIT(0) | BIT(1)) +#define ATLAS7_WDT_EN 0x64 + +static unsigned int timeout = ATLAS7_WDT_DEFAULT_TIMEOUT; +static bool nowayout = WATCHDOG_NOWAYOUT; + +module_param(timeout, uint, 0); +module_param(nowayout, bool, 0); + +MODULE_PARM_DESC(timeout, "Default watchdog timeout (in seconds)"); +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" + __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); + +struct atlas7_wdog { + struct device *dev; + void __iomem *base; + unsigned long tick_rate; + struct clk *clk; +}; + +static unsigned int atlas7_wdt_gettimeleft(struct watchdog_device *wdd) +{ + struct atlas7_wdog *wdt = watchdog_get_drvdata(wdd); + u32 counter, match, delta; + + counter = readl(wdt->base + ATLAS7_WDT_CNT); + match = readl(wdt->base + ATLAS7_WDT_CNT_MATCH); + delta = match - counter; + + return delta / wdt->tick_rate; +} + +static int atlas7_wdt_ping(struct watchdog_device *wdd) +{ + struct atlas7_wdog *wdt = watchdog_get_drvdata(wdd); + u32 counter, match, delta; + + counter = readl(wdt->base + ATLAS7_WDT_CNT); + delta = wdd->timeout * wdt->tick_rate; + match = counter + delta; + + writel(match, wdt->base + ATLAS7_WDT_CNT_MATCH); + + return 0; +} + +static int atlas7_wdt_enable(struct watchdog_device *wdd) +{ + struct atlas7_wdog *wdt = watchdog_get_drvdata(wdd); + + atlas7_wdt_ping(wdd); + + writel(readl(wdt->base + ATLAS7_WDT_CNT_CTRL) | ATLAS7_WDT_CNT_EN, + wdt->base + ATLAS7_WDT_CNT_CTRL); + writel(1, wdt->base + ATLAS7_WDT_EN); + + return 0; +} + +static int atlas7_wdt_disable(struct watchdog_device *wdd) +{ + struct atlas7_wdog *wdt = watchdog_get_drvdata(wdd); + + writel(0, wdt->base + ATLAS7_WDT_EN); + writel(readl(wdt->base + ATLAS7_WDT_CNT_CTRL) & ~ATLAS7_WDT_CNT_EN, + wdt->base + ATLAS7_WDT_CNT_CTRL); + + return 0; +} + +static int atlas7_wdt_settimeout(struct watchdog_device *wdd, unsigned int to) +{ + wdd->timeout = to; + + return 0; +} + +#define OPTIONS (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE) + +static const struct watchdog_info atlas7_wdt_ident = { + .options = OPTIONS, + .firmware_version = 0, + .identity = "atlas7 Watchdog", +}; + +static const struct watchdog_ops atlas7_wdt_ops = { + .owner = THIS_MODULE, + .start = atlas7_wdt_enable, + .stop = atlas7_wdt_disable, + .get_timeleft = atlas7_wdt_gettimeleft, + .ping = atlas7_wdt_ping, + .set_timeout = atlas7_wdt_settimeout, +}; + +static struct watchdog_device atlas7_wdd = { + .info = &atlas7_wdt_ident, + .ops = &atlas7_wdt_ops, + .timeout = ATLAS7_WDT_DEFAULT_TIMEOUT, +}; + +static const struct of_device_id atlas7_wdt_ids[] = { + { .compatible = "sirf,atlas7-tick"}, + {} +}; + +static int atlas7_wdt_probe(struct platform_device *pdev) +{ + struct device_node *np = pdev->dev.of_node; + struct atlas7_wdog *wdt; + struct resource *res; + struct clk *clk; + int ret; + + wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL); + if (!wdt) + return -ENOMEM; + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + wdt->base = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(wdt->base)) + return PTR_ERR(wdt->base); + + clk = of_clk_get(np, 0); + if (IS_ERR(clk)) + return PTR_ERR(clk); + ret = clk_prepare_enable(clk); + if (ret) { + dev_err(&pdev->dev, "clk enable failed\n"); + goto err; + } + + /* disable watchdog hardware */ + writel(0, wdt->base + ATLAS7_WDT_CNT_CTRL); + + wdt->tick_rate = clk_get_rate(clk); + if (!wdt->tick_rate) { + ret = -EINVAL; + goto err1; + } + + wdt->clk = clk; + atlas7_wdd.min_timeout = 1; + atlas7_wdd.max_timeout = UINT_MAX / wdt->tick_rate; + + watchdog_init_timeout(&atlas7_wdd, 0, &pdev->dev); + watchdog_set_nowayout(&atlas7_wdd, nowayout); + + watchdog_set_drvdata(&atlas7_wdd, wdt); + platform_set_drvdata(pdev, &atlas7_wdd); + + ret = watchdog_register_device(&atlas7_wdd); + if (ret) + goto err1; + + return 0; + +err1: + clk_disable_unprepare(clk); +err: + clk_put(clk); + return ret; +} + +static void atlas7_wdt_shutdown(struct platform_device *pdev) +{ + struct watchdog_device *wdd = platform_get_drvdata(pdev); + struct atlas7_wdog *wdt = watchdog_get_drvdata(wdd); + + atlas7_wdt_disable(wdd); + clk_disable_unprepare(wdt->clk); +} + +static int atlas7_wdt_remove(struct platform_device *pdev) +{ + struct watchdog_device *wdd = platform_get_drvdata(pdev); + struct atlas7_wdog *wdt = watchdog_get_drvdata(wdd); + + atlas7_wdt_shutdown(pdev); + clk_put(wdt->clk); + return 0; +} + +static int __maybe_unused atlas7_wdt_suspend(struct device *dev) +{ + /* + * NOTE:timer controller registers settings are saved + * and restored back by the timer-atlas7.c + */ + return 0; +} + +static int __maybe_unused atlas7_wdt_resume(struct device *dev) +{ + struct watchdog_device *wdd = dev_get_drvdata(dev); + + /* + * NOTE: Since timer controller registers settings are saved + * and restored back by the timer-atlas7.c, so we need not + * update WD settings except refreshing timeout. + */ + atlas7_wdt_ping(wdd); + + return 0; +} + +static SIMPLE_DEV_PM_OPS(atlas7_wdt_pm_ops, + atlas7_wdt_suspend, atlas7_wdt_resume); + +MODULE_DEVICE_TABLE(of, atlas7_wdt_ids); + +static struct platform_driver atlas7_wdt_driver = { + .driver = { + .name = "atlas7-wdt", + .pm = &atlas7_wdt_pm_ops, + .of_match_table = atlas7_wdt_ids, + }, + .probe = atlas7_wdt_probe, + .remove = atlas7_wdt_remove, + .shutdown = atlas7_wdt_shutdown, +}; +module_platform_driver(atlas7_wdt_driver); + +MODULE_DESCRIPTION("CSRatlas7 watchdog driver"); +MODULE_AUTHOR("Guo Zeng <Guo.Zeng@csr.com>"); +MODULE_LICENSE("GPL v2"); +MODULE_ALIAS("platform:atlas7-wdt"); |