static int uio_pdrv_genirq_probe()

in uio_pdrv_genirq.c [110:253]

• 99 lines of code
• 24 McCabe index (conditional complexity)

static int uio_pdrv_genirq_probe(struct platform_device *pdev)
{
	struct uio_info *uioinfo = dev_get_platdata(&pdev->dev);
	struct device_node *node = pdev->dev.of_node;
	struct uio_pdrv_genirq_platdata *priv;
	struct uio_mem *uiomem;
	int ret = -EINVAL;
	int i;

	if (node) {
		const char *name;

		/* alloc uioinfo for one device */
		uioinfo = devm_kzalloc(&pdev->dev, sizeof(*uioinfo),
				       GFP_KERNEL);
		if (!uioinfo) {
			dev_err(&pdev->dev, "unable to kmalloc\n");
			return -ENOMEM;
		}

		if (!of_property_read_string(node, "linux,uio-name", &name))
			uioinfo->name = devm_kstrdup(&pdev->dev, name, GFP_KERNEL);
		else
			uioinfo->name = devm_kasprintf(&pdev->dev, GFP_KERNEL,
						       "%pOFn", node);

		uioinfo->version = "devicetree";
		/* Multiple IRQs are not supported */
	}

	if (!uioinfo || !uioinfo->name || !uioinfo->version) {
		dev_err(&pdev->dev, "missing platform_data\n");
		return ret;
	}

	if (uioinfo->handler || uioinfo->irqcontrol ||
	    uioinfo->irq_flags & IRQF_SHARED) {
		dev_err(&pdev->dev, "interrupt configuration error\n");
		return ret;
	}

	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
	if (!priv) {
		dev_err(&pdev->dev, "unable to kmalloc\n");
		return -ENOMEM;
	}

	priv->uioinfo = uioinfo;
	spin_lock_init(&priv->lock);
	priv->flags = 0; /* interrupt is enabled to begin with */
	priv->pdev = pdev;

	if (!uioinfo->irq) {
		ret = platform_get_irq_optional(pdev, 0);
		uioinfo->irq = ret;
		if (ret == -ENXIO)
			uioinfo->irq = UIO_IRQ_NONE;
		else if (ret == -EPROBE_DEFER)
			return ret;
		else if (ret < 0) {
			dev_err(&pdev->dev, "failed to get IRQ\n");
			return ret;
		}
	}

	if (uioinfo->irq) {
		struct irq_data *irq_data = irq_get_irq_data(uioinfo->irq);

		/*
		 * If a level interrupt, dont do lazy disable. Otherwise the
		 * irq will fire again since clearing of the actual cause, on
		 * device level, is done in userspace
		 * irqd_is_level_type() isn't used since isn't valid until
		 * irq is configured.
		 */
		if (irq_data &&
		    irqd_get_trigger_type(irq_data) & IRQ_TYPE_LEVEL_MASK) {
			dev_dbg(&pdev->dev, "disable lazy unmask\n");
			irq_set_status_flags(uioinfo->irq, IRQ_DISABLE_UNLAZY);
		}
	}

	uiomem = &uioinfo->mem[0];

	for (i = 0; i < pdev->num_resources; ++i) {
		struct resource *r = &pdev->resource[i];

		if (r->flags != IORESOURCE_MEM)
			continue;

		if (uiomem >= &uioinfo->mem[MAX_UIO_MAPS]) {
			dev_warn(&pdev->dev, "device has more than "
					__stringify(MAX_UIO_MAPS)
					" I/O memory resources.\n");
			break;
		}

		uiomem->memtype = UIO_MEM_PHYS;
		uiomem->addr = r->start & PAGE_MASK;
		uiomem->offs = r->start & ~PAGE_MASK;
		uiomem->size = (uiomem->offs + resource_size(r)
				+ PAGE_SIZE - 1) & PAGE_MASK;
		uiomem->name = r->name;
		++uiomem;
	}

	while (uiomem < &uioinfo->mem[MAX_UIO_MAPS]) {
		uiomem->size = 0;
		++uiomem;
	}

	/* This driver requires no hardware specific kernel code to handle
	 * interrupts. Instead, the interrupt handler simply disables the
	 * interrupt in the interrupt controller. User space is responsible
	 * for performing hardware specific acknowledge and re-enabling of
	 * the interrupt in the interrupt controller.
	 *
	 * Interrupt sharing is not supported.
	 */

	uioinfo->handler = uio_pdrv_genirq_handler;
	uioinfo->irqcontrol = uio_pdrv_genirq_irqcontrol;
	uioinfo->open = uio_pdrv_genirq_open;
	uioinfo->release = uio_pdrv_genirq_release;
	uioinfo->priv = priv;

	/* Enable Runtime PM for this device:
	 * The device starts in suspended state to allow the hardware to be
	 * turned off by default. The Runtime PM bus code should power on the
	 * hardware and enable clocks at open().
	 */
	pm_runtime_enable(&pdev->dev);

	ret = devm_add_action_or_reset(&pdev->dev, uio_pdrv_genirq_cleanup,
				       &pdev->dev);
	if (ret)
		return ret;

	ret = devm_uio_register_device(&pdev->dev, priv->uioinfo);
	if (ret)
		dev_err(&pdev->dev, "unable to register uio device\n");

	return ret;
}