static int qcom_wdt_probe()

in qcom-wdt.c [193:310]

• 79 lines of code
• 18 McCabe index (conditional complexity)

static int qcom_wdt_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct qcom_wdt *wdt;
	struct resource *res;
	struct device_node *np = dev->of_node;
	const struct qcom_wdt_match_data *data;
	u32 percpu_offset;
	int irq, ret;
	struct clk *clk;

	data = of_device_get_match_data(dev);
	if (!data) {
		dev_err(dev, "Unsupported QCOM WDT module\n");
		return -ENODEV;
	}

	wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
	if (!wdt)
		return -ENOMEM;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res)
		return -ENOMEM;

	/* We use CPU0's DGT for the watchdog */
	if (of_property_read_u32(np, "cpu-offset", &percpu_offset))
		percpu_offset = 0;

	res->start += percpu_offset;
	res->end += percpu_offset;

	wdt->base = devm_ioremap_resource(dev, res);
	if (IS_ERR(wdt->base))
		return PTR_ERR(wdt->base);

	clk = devm_clk_get(dev, NULL);
	if (IS_ERR(clk)) {
		dev_err(dev, "failed to get input clock\n");
		return PTR_ERR(clk);
	}

	ret = clk_prepare_enable(clk);
	if (ret) {
		dev_err(dev, "failed to setup clock\n");
		return ret;
	}
	ret = devm_add_action_or_reset(dev, qcom_clk_disable_unprepare, clk);
	if (ret)
		return ret;

	/*
	 * We use the clock rate to calculate the max timeout, so ensure it's
	 * not zero to avoid a divide-by-zero exception.
	 *
	 * WATCHDOG_CORE assumes units of seconds, if the WDT is clocked such
	 * that it would bite before a second elapses it's usefulness is
	 * limited.  Bail if this is the case.
	 */
	wdt->rate = clk_get_rate(clk);
	if (wdt->rate == 0 ||
	    wdt->rate > 0x10000000U) {
		dev_err(dev, "invalid clock rate\n");
		return -EINVAL;
	}

	/* check if there is pretimeout support */
	irq = platform_get_irq_optional(pdev, 0);
	if (data->pretimeout && irq > 0) {
		ret = devm_request_irq(dev, irq, qcom_wdt_isr, 0,
				       "wdt_bark", &wdt->wdd);
		if (ret)
			return ret;

		wdt->wdd.info = &qcom_wdt_pt_info;
		wdt->wdd.pretimeout = 1;
	} else {
		if (irq == -EPROBE_DEFER)
			return -EPROBE_DEFER;

		wdt->wdd.info = &qcom_wdt_info;
	}

	wdt->wdd.ops = &qcom_wdt_ops;
	wdt->wdd.min_timeout = 1;
	wdt->wdd.max_timeout = 0x10000000U / wdt->rate;
	wdt->wdd.parent = dev;
	wdt->layout = data->offset;

	if (readl(wdt_addr(wdt, WDT_STS)) & 1)
		wdt->wdd.bootstatus = WDIOF_CARDRESET;

	/*
	 * If 'timeout-sec' unspecified in devicetree, assume a 30 second
	 * default, unless the max timeout is less than 30 seconds, then use
	 * the max instead.
	 */
	wdt->wdd.timeout = min(wdt->wdd.max_timeout, 30U);
	watchdog_init_timeout(&wdt->wdd, 0, dev);

	/*
	 * If WDT is already running, call WDT start which
	 * will stop the WDT, set timeouts as bootloader
	 * might use different ones and set running bit
	 * to inform the WDT subsystem to ping the WDT
	 */
	if (qcom_wdt_is_running(&wdt->wdd)) {
		qcom_wdt_start(&wdt->wdd);
		set_bit(WDOG_HW_RUNNING, &wdt->wdd.status);
	}

	ret = devm_watchdog_register_device(dev, &wdt->wdd);
	if (ret)
		return ret;

	platform_set_drvdata(pdev, wdt);
	return 0;
}