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drivers/watchdog/sama5d4_wdt.c
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81f7e3824 Initial Release, ... |
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/* * Driver for Atmel SAMA5D4 Watchdog Timer * * Copyright (C) 2015 Atmel Corporation * * Licensed under GPLv2. */ #include <linux/delay.h> #include <linux/interrupt.h> #include <linux/io.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/of.h> #include <linux/of_irq.h> #include <linux/platform_device.h> #include <linux/reboot.h> #include <linux/watchdog.h> #include "at91sam9_wdt.h" /* minimum and maximum watchdog timeout, in seconds */ #define MIN_WDT_TIMEOUT 1 #define MAX_WDT_TIMEOUT 16 #define WDT_DEFAULT_TIMEOUT MAX_WDT_TIMEOUT #define WDT_SEC2TICKS(s) ((s) ? (((s) << 8) - 1) : 0) struct sama5d4_wdt { struct watchdog_device wdd; void __iomem *reg_base; u32 mr; unsigned long last_ping; }; static int wdt_timeout = WDT_DEFAULT_TIMEOUT; static bool nowayout = WATCHDOG_NOWAYOUT; module_param(wdt_timeout, int, 0); MODULE_PARM_DESC(wdt_timeout, "Watchdog timeout in seconds. (default = " __MODULE_STRING(WDT_DEFAULT_TIMEOUT) ")"); module_param(nowayout, bool, 0); MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); #define wdt_enabled (!(wdt->mr & AT91_WDT_WDDIS)) #define wdt_read(wdt, field) \ readl_relaxed((wdt)->reg_base + (field)) /* 4 slow clock periods is 4/32768 = 122.07µs*/ #define WDT_DELAY usecs_to_jiffies(123) static void wdt_write(struct sama5d4_wdt *wdt, u32 field, u32 val) { /* * WDT_CR and WDT_MR must not be modified within three slow clock * periods following a restart of the watchdog performed by a write * access in WDT_CR. */ while (time_before(jiffies, wdt->last_ping + WDT_DELAY)) usleep_range(30, 125); writel_relaxed(val, wdt->reg_base + field); wdt->last_ping = jiffies; } static void wdt_write_nosleep(struct sama5d4_wdt *wdt, u32 field, u32 val) { if (time_before(jiffies, wdt->last_ping + WDT_DELAY)) udelay(123); writel_relaxed(val, wdt->reg_base + field); wdt->last_ping = jiffies; } static int sama5d4_wdt_start(struct watchdog_device *wdd) { struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd); wdt->mr &= ~AT91_WDT_WDDIS; wdt_write(wdt, AT91_WDT_MR, wdt->mr); return 0; } static int sama5d4_wdt_stop(struct watchdog_device *wdd) { struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd); wdt->mr |= AT91_WDT_WDDIS; wdt_write(wdt, AT91_WDT_MR, wdt->mr); return 0; } static int sama5d4_wdt_ping(struct watchdog_device *wdd) { struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd); wdt_write(wdt, AT91_WDT_CR, AT91_WDT_KEY | AT91_WDT_WDRSTT); return 0; } static int sama5d4_wdt_set_timeout(struct watchdog_device *wdd, unsigned int timeout) { struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd); u32 value = WDT_SEC2TICKS(timeout); wdt->mr &= ~AT91_WDT_WDV; wdt->mr &= ~AT91_WDT_WDD; wdt->mr |= AT91_WDT_SET_WDV(value); wdt->mr |= AT91_WDT_SET_WDD(value); /* * WDDIS has to be 0 when updating WDD/WDV. The datasheet states: When * setting the WDDIS bit, and while it is set, the fields WDV and WDD * must not be modified. * If the watchdog is enabled, then the timeout can be updated. Else, * wait that the user enables it. */ if (wdt_enabled) wdt_write(wdt, AT91_WDT_MR, wdt->mr & ~AT91_WDT_WDDIS); wdd->timeout = timeout; return 0; } static const struct watchdog_info sama5d4_wdt_info = { .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING, .identity = "Atmel SAMA5D4 Watchdog", }; static const struct watchdog_ops sama5d4_wdt_ops = { .owner = THIS_MODULE, .start = sama5d4_wdt_start, .stop = sama5d4_wdt_stop, .ping = sama5d4_wdt_ping, .set_timeout = sama5d4_wdt_set_timeout, }; static irqreturn_t sama5d4_wdt_irq_handler(int irq, void *dev_id) { struct sama5d4_wdt *wdt = platform_get_drvdata(dev_id); if (wdt_read(wdt, AT91_WDT_SR)) { pr_crit("Atmel Watchdog Software Reset "); emergency_restart(); pr_crit("Reboot didn't succeed "); } return IRQ_HANDLED; } static int of_sama5d4_wdt_init(struct device_node *np, struct sama5d4_wdt *wdt) { const char *tmp; wdt->mr = AT91_WDT_WDDIS; if (!of_property_read_string(np, "atmel,watchdog-type", &tmp) && !strcmp(tmp, "software")) wdt->mr |= AT91_WDT_WDFIEN; else wdt->mr |= AT91_WDT_WDRSTEN; if (of_property_read_bool(np, "atmel,idle-halt")) wdt->mr |= AT91_WDT_WDIDLEHLT; if (of_property_read_bool(np, "atmel,dbg-halt")) wdt->mr |= AT91_WDT_WDDBGHLT; return 0; } static int sama5d4_wdt_init(struct sama5d4_wdt *wdt) { u32 reg; /* * When booting and resuming, the bootloader may have changed the * watchdog configuration. * If the watchdog is already running, we can safely update it. * Else, we have to disable it properly. */ if (wdt_enabled) { wdt_write_nosleep(wdt, AT91_WDT_MR, wdt->mr); } else { reg = wdt_read(wdt, AT91_WDT_MR); if (!(reg & AT91_WDT_WDDIS)) wdt_write_nosleep(wdt, AT91_WDT_MR, reg | AT91_WDT_WDDIS); } return 0; } static int sama5d4_wdt_probe(struct platform_device *pdev) { struct watchdog_device *wdd; struct sama5d4_wdt *wdt; struct resource *res; void __iomem *regs; u32 irq = 0; u32 timeout; int ret; wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL); if (!wdt) return -ENOMEM; wdd = &wdt->wdd; wdd->timeout = wdt_timeout; wdd->info = &sama5d4_wdt_info; wdd->ops = &sama5d4_wdt_ops; wdd->min_timeout = MIN_WDT_TIMEOUT; wdd->max_timeout = MAX_WDT_TIMEOUT; wdt->last_ping = jiffies; watchdog_set_drvdata(wdd, wdt); res = platform_get_resource(pdev, IORESOURCE_MEM, 0); regs = devm_ioremap_resource(&pdev->dev, res); if (IS_ERR(regs)) return PTR_ERR(regs); wdt->reg_base = regs; irq = irq_of_parse_and_map(pdev->dev.of_node, 0); if (!irq) dev_warn(&pdev->dev, "failed to get IRQ from DT "); ret = of_sama5d4_wdt_init(pdev->dev.of_node, wdt); if (ret) return ret; if ((wdt->mr & AT91_WDT_WDFIEN) && irq) { ret = devm_request_irq(&pdev->dev, irq, sama5d4_wdt_irq_handler, IRQF_SHARED | IRQF_IRQPOLL | IRQF_NO_SUSPEND, pdev->name, pdev); if (ret) { dev_err(&pdev->dev, "cannot register interrupt handler "); return ret; } } ret = watchdog_init_timeout(wdd, wdt_timeout, &pdev->dev); if (ret) { dev_err(&pdev->dev, "unable to set timeout value "); return ret; } timeout = WDT_SEC2TICKS(wdd->timeout); wdt->mr |= AT91_WDT_SET_WDD(timeout); wdt->mr |= AT91_WDT_SET_WDV(timeout); ret = sama5d4_wdt_init(wdt); if (ret) return ret; watchdog_set_nowayout(wdd, nowayout); ret = watchdog_register_device(wdd); if (ret) { dev_err(&pdev->dev, "failed to register watchdog device "); return ret; } platform_set_drvdata(pdev, wdt); dev_info(&pdev->dev, "initialized (timeout = %d sec, nowayout = %d) ", wdt_timeout, nowayout); return 0; } static int sama5d4_wdt_remove(struct platform_device *pdev) { struct sama5d4_wdt *wdt = platform_get_drvdata(pdev); sama5d4_wdt_stop(&wdt->wdd); watchdog_unregister_device(&wdt->wdd); return 0; } static const struct of_device_id sama5d4_wdt_of_match[] = { { .compatible = "atmel,sama5d4-wdt", }, { } }; MODULE_DEVICE_TABLE(of, sama5d4_wdt_of_match); #ifdef CONFIG_PM_SLEEP static int sama5d4_wdt_resume(struct device *dev) { struct sama5d4_wdt *wdt = dev_get_drvdata(dev); /* * FIXME: writing MR also pings the watchdog which may not be desired. * This should only be done when the registers are lost on suspend but * there is no way to get this information right now. */ sama5d4_wdt_init(wdt); return 0; } #endif static SIMPLE_DEV_PM_OPS(sama5d4_wdt_pm_ops, NULL, sama5d4_wdt_resume); static struct platform_driver sama5d4_wdt_driver = { .probe = sama5d4_wdt_probe, .remove = sama5d4_wdt_remove, .driver = { .name = "sama5d4_wdt", .pm = &sama5d4_wdt_pm_ops, .of_match_table = sama5d4_wdt_of_match, } }; module_platform_driver(sama5d4_wdt_driver); MODULE_AUTHOR("Atmel Corporation"); MODULE_DESCRIPTION("Atmel SAMA5D4 Watchdog Timer driver"); MODULE_LICENSE("GPL v2"); |