+void * __weak __init swiotlb_alloc_boot(size_t size, unsigned long nslabs)
+{
+ return alloc_bootmem_low_pages(size);
+}
+
+void * __weak swiotlb_alloc(unsigned order, unsigned long nslabs)
+{
+ return (void *)__get_free_pages(GFP_DMA | __GFP_NOWARN, order);
+}
+
+dma_addr_t __weak swiotlb_phys_to_bus(phys_addr_t paddr)
+{
+ return paddr;
+}
+
+phys_addr_t __weak swiotlb_bus_to_phys(dma_addr_t baddr)
+{
+ return baddr;
+}
+
+static dma_addr_t swiotlb_virt_to_bus(volatile void *address)
+{
+ return swiotlb_phys_to_bus(virt_to_phys(address));
+}
+
+static void *swiotlb_bus_to_virt(dma_addr_t address)
+{
+ return phys_to_virt(swiotlb_bus_to_phys(address));
+}
+
+int __weak swiotlb_arch_range_needs_mapping(void *ptr, size_t size)
+{
+ return 0;
+}
+
+static dma_addr_t swiotlb_sg_to_bus(struct scatterlist *sg)
+{
+ return swiotlb_phys_to_bus(page_to_phys(sg_page(sg)) + sg->offset);
+}
+
+static void swiotlb_print_info(unsigned long bytes)
+{
+ phys_addr_t pstart, pend;
+ dma_addr_t bstart, bend;
+
+ pstart = virt_to_phys(io_tlb_start);
+ pend = virt_to_phys(io_tlb_end);
+
+ bstart = swiotlb_phys_to_bus(pstart);
+ bend = swiotlb_phys_to_bus(pend);
+
+ printk(KERN_INFO "Placing %luMB software IO TLB between %p - %p\n",
+ bytes >> 20, io_tlb_start, io_tlb_end);
+ if (pstart != bstart || pend != bend)
+ printk(KERN_INFO "software IO TLB at phys %#llx - %#llx"
+ " bus %#llx - %#llx\n",
+ (unsigned long long)pstart,
+ (unsigned long long)pend,
+ (unsigned long long)bstart,
+ (unsigned long long)bend);
+ else
+ printk(KERN_INFO "software IO TLB at phys %#llx - %#llx\n",
+ (unsigned long long)pstart,
+ (unsigned long long)pend);
+}
+