static int alpha_pci_supported()

in kernel/pci_iommu.c [792:820]

• 20 lines of code
• 11 McCabe index (conditional complexity)

static int alpha_pci_supported(struct device *dev, u64 mask)
{
	struct pci_dev *pdev = alpha_gendev_to_pci(dev);
	struct pci_controller *hose;
	struct pci_iommu_arena *arena;

	/* If there exists a direct map, and the mask fits either
	   the entire direct mapped space or the total system memory as
	   shifted by the map base */
	if (__direct_map_size != 0
	    && (__direct_map_base + __direct_map_size - 1 <= mask ||
		__direct_map_base + (max_low_pfn << PAGE_SHIFT) - 1 <= mask))
		return 1;

	/* Check that we have a scatter-gather arena that fits.  */
	hose = pdev ? pdev->sysdata : pci_isa_hose;
	arena = hose->sg_isa;
	if (arena && arena->dma_base + arena->size - 1 <= mask)
		return 1;
	arena = hose->sg_pci;
	if (arena && arena->dma_base + arena->size - 1 <= mask)
		return 1;

	/* As last resort try ZONE_DMA.  */
	if (!__direct_map_base && MAX_DMA_ADDRESS - IDENT_ADDR - 1 <= mask)
		return 1;

	return 0;
}