static dma_addr_t sba_map_page()

in hp/common/sba_iommu.c [911:996]

• 61 lines of code
• 5 McCabe index (conditional complexity)

static dma_addr_t sba_map_page(struct device *dev, struct page *page,
			       unsigned long poff, size_t size,
			       enum dma_data_direction dir,
			       unsigned long attrs)
{
	struct ioc *ioc;
	void *addr = page_address(page) + poff;
	dma_addr_t iovp;
	dma_addr_t offset;
	u64 *pdir_start;
	int pide;
#ifdef ASSERT_PDIR_SANITY
	unsigned long flags;
#endif
#ifdef ALLOW_IOV_BYPASS
	unsigned long pci_addr = virt_to_phys(addr);
#endif

#ifdef ALLOW_IOV_BYPASS
	ASSERT(to_pci_dev(dev)->dma_mask);
	/*
 	** Check if the PCI device can DMA to ptr... if so, just return ptr
 	*/
	if (likely((pci_addr & ~to_pci_dev(dev)->dma_mask) == 0)) {
		/*
 		** Device is bit capable of DMA'ing to the buffer...
		** just return the PCI address of ptr
 		*/
		DBG_BYPASS("sba_map_page() bypass mask/addr: "
			   "0x%lx/0x%lx\n",
		           to_pci_dev(dev)->dma_mask, pci_addr);
		return pci_addr;
	}
#endif
	ioc = GET_IOC(dev);
	ASSERT(ioc);

	prefetch(ioc->res_hint);

	ASSERT(size > 0);
	ASSERT(size <= DMA_CHUNK_SIZE);

	/* save offset bits */
	offset = ((dma_addr_t) (long) addr) & ~iovp_mask;

	/* round up to nearest iovp_size */
	size = (size + offset + ~iovp_mask) & iovp_mask;

#ifdef ASSERT_PDIR_SANITY
	spin_lock_irqsave(&ioc->res_lock, flags);
	if (sba_check_pdir(ioc,"Check before sba_map_page()"))
		panic("Sanity check failed");
	spin_unlock_irqrestore(&ioc->res_lock, flags);
#endif

	pide = sba_alloc_range(ioc, dev, size);
	if (pide < 0)
		return DMA_MAPPING_ERROR;

	iovp = (dma_addr_t) pide << iovp_shift;

	DBG_RUN("%s() 0x%p -> 0x%lx\n", __func__, addr, (long) iovp | offset);

	pdir_start = &(ioc->pdir_base[pide]);

	while (size > 0) {
		ASSERT(((u8 *)pdir_start)[7] == 0); /* verify availability */
		sba_io_pdir_entry(pdir_start, (unsigned long) addr);

		DBG_RUN("     pdir 0x%p %lx\n", pdir_start, *pdir_start);

		addr += iovp_size;
		size -= iovp_size;
		pdir_start++;
	}
	/* force pdir update */
	wmb();

	/* form complete address */
#ifdef ASSERT_PDIR_SANITY
	spin_lock_irqsave(&ioc->res_lock, flags);
	sba_check_pdir(ioc,"Check after sba_map_page()");
	spin_unlock_irqrestore(&ioc->res_lock, flags);
#endif
	return SBA_IOVA(ioc, iovp, offset);
}