drivers/watchdog/intel-mid_wdt.c

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

File Facts

System
Linux kernel
Corpus path
drivers/watchdog/intel-mid_wdt.c
Extension
.c
Size
5189 bytes
Lines
211
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 mid_wdt {
	struct watchdog_device wd;
	struct device *dev;
	struct intel_scu_ipc_dev *scu;
};

static inline int
wdt_command(struct mid_wdt *mid, int sub, const void *in, size_t inlen, size_t size)
{
	struct intel_scu_ipc_dev *scu = mid->scu;

	return intel_scu_ipc_dev_command_with_size(scu, IPC_WATCHDOG, sub, in,
						   inlen, size, NULL, 0);
}

static int wdt_start(struct watchdog_device *wd)
{
	struct mid_wdt *mid = watchdog_get_drvdata(wd);
	int ret, in_size;
	int timeout = wd->timeout;
	struct ipc_wd_start {
		u32 pretimeout;
		u32 timeout;
	} ipc_wd_start = { timeout - MID_WDT_PRETIMEOUT, timeout };

	/*
	 * SCU expects the input size for watchdog IPC to be 2 which is the
	 * size of the structure in dwords. SCU IPC normally takes bytes
	 * but this is a special case where we specify size to be different
	 * than inlen.
	 */
	in_size = DIV_ROUND_UP(sizeof(ipc_wd_start), 4);

	ret = wdt_command(mid, SCU_WATCHDOG_START, &ipc_wd_start,
			  sizeof(ipc_wd_start), in_size);
	if (ret)
		dev_crit(mid->dev, "error starting watchdog: %d\n", ret);

	return ret;
}

static int wdt_ping(struct watchdog_device *wd)
{
	struct mid_wdt *mid = watchdog_get_drvdata(wd);
	int ret;

	ret = wdt_command(mid, SCU_WATCHDOG_KEEPALIVE, NULL, 0, 0);
	if (ret)
		dev_crit(mid->dev, "Error executing keepalive: %d\n", ret);

	return ret;
}

static int wdt_stop(struct watchdog_device *wd)
{
	struct mid_wdt *mid = watchdog_get_drvdata(wd);
	int ret;

	ret = wdt_command(mid, SCU_WATCHDOG_STOP, NULL, 0, 0);
	if (ret)
		dev_crit(mid->dev, "Error stopping watchdog: %d\n", ret);

	return ret;
}

static irqreturn_t mid_wdt_irq(int irq, void *dev_id)
{
	panic("Kernel Watchdog");

	/* This code should not be reached */
	return IRQ_HANDLED;
}

static const struct watchdog_info mid_wdt_info = {
	.identity = "Intel MID SCU watchdog",
	.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
};

static const struct watchdog_ops mid_wdt_ops = {
	.owner = THIS_MODULE,
	.start = wdt_start,
	.stop = wdt_stop,
	.ping = wdt_ping,
};

static int mid_wdt_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct watchdog_device *wdt_dev;
	struct intel_mid_wdt_pdata *pdata = dev_get_platdata(dev);

Annotation

Implementation Notes