int vp_legacy_probe()

in virtio_pci_legacy_dev.c [16:62]

• 33 lines of code
• 7 McCabe index (conditional complexity)

int vp_legacy_probe(struct virtio_pci_legacy_device *ldev)
{
	struct pci_dev *pci_dev = ldev->pci_dev;
	int rc;

	/* We only own devices >= 0x1000 and <= 0x103f: leave the rest. */
	if (pci_dev->device < 0x1000 || pci_dev->device > 0x103f)
		return -ENODEV;

	if (pci_dev->revision != VIRTIO_PCI_ABI_VERSION)
		return -ENODEV;

	rc = dma_set_mask(&pci_dev->dev, DMA_BIT_MASK(64));
	if (rc) {
		rc = dma_set_mask_and_coherent(&pci_dev->dev, DMA_BIT_MASK(32));
	} else {
		/*
		 * The virtio ring base address is expressed as a 32-bit PFN,
		 * with a page size of 1 << VIRTIO_PCI_QUEUE_ADDR_SHIFT.
		 */
		dma_set_coherent_mask(&pci_dev->dev,
				DMA_BIT_MASK(32 + VIRTIO_PCI_QUEUE_ADDR_SHIFT));
	}

	if (rc)
		dev_warn(&pci_dev->dev, "Failed to enable 64-bit or 32-bit DMA.  Trying to continue, but this might not work.\n");

	rc = pci_request_region(pci_dev, 0, "virtio-pci-legacy");
	if (rc)
		return rc;

	ldev->ioaddr = pci_iomap(pci_dev, 0, 0);
	if (!ldev->ioaddr) {
		rc = -EIO;
		goto err_iomap;
	}

	ldev->isr = ldev->ioaddr + VIRTIO_PCI_ISR;

	ldev->id.vendor = pci_dev->subsystem_vendor;
	ldev->id.device = pci_dev->subsystem_device;

	return 0;
err_iomap:
	pci_release_region(pci_dev, 0);
	return rc;
}