drivers/watchdog/airoha_wdt.c

Source file repositories/reference/linux-study-clean/drivers/watchdog/airoha_wdt.c

File Facts

System
Linux kernel
Corpus path
drivers/watchdog/airoha_wdt.c
Extension
.c
Size
5773 bytes
Lines
217
Domain
Driver Families
Bucket
drivers/watchdog
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

struct airoha_wdt_desc {
	struct watchdog_device wdog_dev;
	unsigned int wdt_freq;
	void __iomem *base;
};

#define WDT_HEARTBEAT			24
static int heartbeat = WDT_HEARTBEAT;
module_param(heartbeat, int, 0);
MODULE_PARM_DESC(heartbeat, "Watchdog heartbeats in seconds. (default="
		 __MODULE_STRING(WDT_HEARTBEAT) ")");

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 int airoha_wdt_start(struct watchdog_device *wdog_dev)
{
	struct airoha_wdt_desc *airoha_wdt = watchdog_get_drvdata(wdog_dev);
	u32 val;

	val = readl(airoha_wdt->base + TIMER_CTRL);
	val |= (WDT_TIMER_ENABLE | WDT_ENABLE | WDT_TIMER_INTERRUPT);
	writel(val, airoha_wdt->base + TIMER_CTRL);
	val = wdog_dev->timeout * airoha_wdt->wdt_freq;
	writel(val, airoha_wdt->base + WDT_TIMER_LOAD_VALUE);

	return 0;
}

static int airoha_wdt_stop(struct watchdog_device *wdog_dev)
{
	struct airoha_wdt_desc *airoha_wdt = watchdog_get_drvdata(wdog_dev);
	u32 val;

	val = readl(airoha_wdt->base + TIMER_CTRL);
	val &= (~WDT_ENABLE & ~WDT_TIMER_ENABLE);
	writel(val, airoha_wdt->base + TIMER_CTRL);

	return 0;
}

static int airoha_wdt_ping(struct watchdog_device *wdog_dev)
{
	struct airoha_wdt_desc *airoha_wdt = watchdog_get_drvdata(wdog_dev);
	u32 val;

	val = readl(airoha_wdt->base + WDT_RELOAD);
	val |= WDT_RLD;
	writel(val, airoha_wdt->base + WDT_RELOAD);

	return 0;
}

static int airoha_wdt_set_timeout(struct watchdog_device *wdog_dev, unsigned int timeout)
{
	wdog_dev->timeout = timeout;

	if (watchdog_active(wdog_dev)) {
		airoha_wdt_stop(wdog_dev);
		return airoha_wdt_start(wdog_dev);
	}

	return 0;
}

static unsigned int airoha_wdt_get_timeleft(struct watchdog_device *wdog_dev)
{
	struct airoha_wdt_desc *airoha_wdt = watchdog_get_drvdata(wdog_dev);
	u32 val;

	val = readl(airoha_wdt->base + WDT_TIMER_CUR_VALUE);
	return DIV_ROUND_UP(val, airoha_wdt->wdt_freq);
}

static const struct watchdog_info airoha_wdt_info = {
	.options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
	.identity = "Airoha Watchdog",
};

static const struct watchdog_ops airoha_wdt_ops = {
	.owner = THIS_MODULE,
	.start = airoha_wdt_start,
	.stop = airoha_wdt_stop,
	.ping = airoha_wdt_ping,
	.set_timeout = airoha_wdt_set_timeout,
	.get_timeleft = airoha_wdt_get_timeleft,
};

Annotation

Implementation Notes