diff options
Diffstat (limited to 'drivers/watchdog/sama5d4_wdt.c')
| -rw-r--r-- | drivers/watchdog/sama5d4_wdt.c | 280 |
1 files changed, 280 insertions, 0 deletions
diff --git a/drivers/watchdog/sama5d4_wdt.c b/drivers/watchdog/sama5d4_wdt.c new file mode 100644 index 000000000000..a49634cdc1cc --- /dev/null +++ b/drivers/watchdog/sama5d4_wdt.c @@ -0,0 +1,280 @@ +/* + * Driver for Atmel SAMA5D4 Watchdog Timer + * + * Copyright (C) 2015 Atmel Corporation + * + * Licensed under GPLv2. + */ + +#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 config; +}; + +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_read(wdt, field) \ + readl_relaxed((wdt)->reg_base + (field)) + +#define wdt_write(wtd, field, val) \ + writel_relaxed((val), (wdt)->reg_base + (field)) + +static int sama5d4_wdt_start(struct watchdog_device *wdd) +{ + struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd); + u32 reg; + + reg = wdt_read(wdt, AT91_WDT_MR); + reg &= ~AT91_WDT_WDDIS; + wdt_write(wdt, AT91_WDT_MR, reg); + + return 0; +} + +static int sama5d4_wdt_stop(struct watchdog_device *wdd) +{ + struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd); + u32 reg; + + reg = wdt_read(wdt, AT91_WDT_MR); + reg |= AT91_WDT_WDDIS; + wdt_write(wdt, AT91_WDT_MR, reg); + + 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); + u32 reg; + + reg = wdt_read(wdt, AT91_WDT_MR); + reg &= ~AT91_WDT_WDV; + reg &= ~AT91_WDT_WDD; + reg |= AT91_WDT_SET_WDV(value); + reg |= AT91_WDT_SET_WDD(value); + wdt_write(wdt, AT91_WDT_MR, reg); + + 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 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\n"); + emergency_restart(); + pr_crit("Reboot didn't succeed\n"); + } + + return IRQ_HANDLED; +} + +static int of_sama5d4_wdt_init(struct device_node *np, struct sama5d4_wdt *wdt) +{ + const char *tmp; + + wdt->config = AT91_WDT_WDDIS; + + if (!of_property_read_string(np, "atmel,watchdog-type", &tmp) && + !strcmp(tmp, "software")) + wdt->config |= AT91_WDT_WDFIEN; + else + wdt->config |= AT91_WDT_WDRSTEN; + + if (of_property_read_bool(np, "atmel,idle-halt")) + wdt->config |= AT91_WDT_WDIDLEHLT; + + if (of_property_read_bool(np, "atmel,dbg-halt")) + wdt->config |= AT91_WDT_WDDBGHLT; + + return 0; +} + +static int sama5d4_wdt_init(struct sama5d4_wdt *wdt) +{ + struct watchdog_device *wdd = &wdt->wdd; + u32 value = WDT_SEC2TICKS(wdd->timeout); + u32 reg; + + /* + * Because the fields WDV and WDD must not be modified when the WDDIS + * bit is set, so clear the WDDIS bit before writing the WDT_MR. + */ + reg = wdt_read(wdt, AT91_WDT_MR); + reg &= ~AT91_WDT_WDDIS; + wdt_write(wdt, AT91_WDT_MR, reg); + + reg = wdt->config; + reg |= AT91_WDT_SET_WDD(value); + reg |= AT91_WDT_SET_WDV(value); + + wdt_write(wdt, AT91_WDT_MR, reg); + + 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; + 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; + + 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; + + if (pdev->dev.of_node) { + irq = irq_of_parse_and_map(pdev->dev.of_node, 0); + if (!irq) + dev_warn(&pdev->dev, "failed to get IRQ from DT\n"); + + ret = of_sama5d4_wdt_init(pdev->dev.of_node, wdt); + if (ret) + return ret; + } + + if ((wdt->config & 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\n"); + return ret; + } + } + + ret = watchdog_init_timeout(wdd, wdt_timeout, &pdev->dev); + if (ret) { + dev_err(&pdev->dev, "unable to set timeout value\n"); + return ret; + } + + 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\n"); + return ret; + } + + platform_set_drvdata(pdev, wdt); + + dev_info(&pdev->dev, "initialized (timeout = %d sec, nowayout = %d)\n", + 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); + +static struct platform_driver sama5d4_wdt_driver = { + .probe = sama5d4_wdt_probe, + .remove = sama5d4_wdt_remove, + .driver = { + .name = "sama5d4_wdt", + .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"); |