static int acpi_pci_link_set()

in pci_link.c [277:386]

• 84 lines of code
• 13 McCabe index (conditional complexity)

static int acpi_pci_link_set(struct acpi_pci_link *link, int irq)
{
	struct {
		struct acpi_resource res;
		struct acpi_resource end;
	} *resource;
	struct acpi_buffer buffer = { 0, NULL };
	acpi_handle handle = link->device->handle;
	acpi_status status;
	int result;

	if (!irq)
		return -EINVAL;

	resource = kzalloc(sizeof(*resource) + 1, irqs_disabled() ? GFP_ATOMIC: GFP_KERNEL);
	if (!resource)
		return -ENOMEM;

	buffer.length = sizeof(*resource) + 1;
	buffer.pointer = resource;

	switch (link->irq.resource_type) {
	case ACPI_RESOURCE_TYPE_IRQ:
		resource->res.type = ACPI_RESOURCE_TYPE_IRQ;
		resource->res.length = sizeof(struct acpi_resource);
		resource->res.data.irq.triggering = link->irq.triggering;
		resource->res.data.irq.polarity =
		    link->irq.polarity;
		if (link->irq.triggering == ACPI_EDGE_SENSITIVE)
			resource->res.data.irq.shareable =
			    ACPI_EXCLUSIVE;
		else
			resource->res.data.irq.shareable = ACPI_SHARED;
		resource->res.data.irq.interrupt_count = 1;
		resource->res.data.irq.interrupts[0] = irq;
		break;

	case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
		resource->res.type = ACPI_RESOURCE_TYPE_EXTENDED_IRQ;
		resource->res.length = sizeof(struct acpi_resource);
		resource->res.data.extended_irq.producer_consumer =
		    ACPI_CONSUMER;
		resource->res.data.extended_irq.triggering =
		    link->irq.triggering;
		resource->res.data.extended_irq.polarity =
		    link->irq.polarity;
		if (link->irq.triggering == ACPI_EDGE_SENSITIVE)
			resource->res.data.extended_irq.shareable =
			    ACPI_EXCLUSIVE;
		else
			resource->res.data.extended_irq.shareable = ACPI_SHARED;
		resource->res.data.extended_irq.interrupt_count = 1;
		resource->res.data.extended_irq.interrupts[0] = irq;
		/* ignore resource_source, it's optional */
		break;
	default:
		acpi_handle_err(handle, "Invalid resource type %d\n",
				link->irq.resource_type);
		result = -EINVAL;
		goto end;

	}
	resource->end.type = ACPI_RESOURCE_TYPE_END_TAG;
	resource->end.length = sizeof(struct acpi_resource);

	/* Attempt to set the resource */
	status = acpi_set_current_resources(link->device->handle, &buffer);

	/* check for total failure */
	if (ACPI_FAILURE(status)) {
		acpi_evaluation_failure_warn(handle, "_SRS", status);
		result = -ENODEV;
		goto end;
	}

	/* Query _STA, set device->status */
	result = acpi_bus_get_status(link->device);
	if (result) {
		acpi_handle_err(handle, "Unable to read status\n");
		goto end;
	}
	if (!link->device->status.enabled)
		acpi_handle_warn(handle, "Disabled and referenced, BIOS bug\n");

	/* Query _CRS, set link->irq.active */
	result = acpi_pci_link_get_current(link);
	if (result) {
		goto end;
	}

	/*
	 * Is current setting not what we set?
	 * set link->irq.active
	 */
	if (link->irq.active != irq) {
		/*
		 * policy: when _CRS doesn't return what we just _SRS
		 * assume _SRS worked and override _CRS value.
		 */
		acpi_handle_warn(handle, "BIOS reported IRQ %d, using IRQ %d\n",
				 link->irq.active, irq);
		link->irq.active = irq;
	}

	acpi_handle_debug(handle, "Set IRQ %d\n", link->irq.active);

      end:
	kfree(resource);
	return result;
}