static void swiotlb_bounce(struct device *dev, phys_addr_t tlb_addr, size_t size,
			   enum dma_data_direction dir)
{
	struct io_tlb_mem *mem = dev->dma_io_tlb_mem;
	int index = (tlb_addr - mem->start) >> IO_TLB_SHIFT;
	phys_addr_t orig_addr = mem->slots[index].orig_addr;
	size_t alloc_size = mem->slots[index].alloc_size;
	unsigned long pfn = PFN_DOWN(orig_addr);
	unsigned char *vaddr = mem->vaddr + tlb_addr - mem->start;
	unsigned int tlb_offset, orig_addr_offset;

	if (orig_addr == INVALID_PHYS_ADDR)
		return;

	tlb_offset = tlb_addr & (IO_TLB_SIZE - 1);
	orig_addr_offset = swiotlb_align_offset(dev, orig_addr);
	if (tlb_offset < orig_addr_offset) {
		dev_WARN_ONCE(dev, 1,
			"Access before mapping start detected. orig offset %u, requested offset %u.\n",
			orig_addr_offset, tlb_offset);
		return;
	}

	tlb_offset -= orig_addr_offset;
	if (tlb_offset > alloc_size) {
		dev_WARN_ONCE(dev, 1,
			"Buffer overflow detected. Allocation size: %zu. Mapping size: %zu+%u.\n",
			alloc_size, size, tlb_offset);
		return;
	}

	orig_addr += tlb_offset;
	alloc_size -= tlb_offset;

	if (size > alloc_size) {
		dev_WARN_ONCE(dev, 1,
			"Buffer overflow detected. Allocation size: %zu. Mapping size: %zu.\n",
			alloc_size, size);
		size = alloc_size;
	}

	if (PageHighMem(pfn_to_page(pfn))) {
		/* The buffer does not have a mapping.  Map it in and copy */
		unsigned int offset = orig_addr & ~PAGE_MASK;
		char *buffer;
		unsigned int sz = 0;
		unsigned long flags;

		while (size) {
			sz = min_t(size_t, PAGE_SIZE - offset, size);

			local_irq_save(flags);
			buffer = kmap_atomic(pfn_to_page(pfn));
			if (dir == DMA_TO_DEVICE)
				memcpy(vaddr, buffer + offset, sz);
			else
				memcpy(buffer + offset, vaddr, sz);
			kunmap_atomic(buffer);
			local_irq_restore(flags);

			size -= sz;
			pfn++;
			vaddr += sz;
			offset = 0;
		}
	} else if (dir == DMA_TO_DEVICE) {
		memcpy(vaddr, phys_to_virt(orig_addr), size);
	} else {
		memcpy(phys_to_virt(orig_addr), vaddr, size);
	}
}
static void swiotlb_bounce(struct device *dev, phys_addr_t tlb_addr, size_t size,
			   enum dma_data_direction dir)
{
	struct io_tlb_mem *mem = dev->dma_io_tlb_mem;
	int index = (tlb_addr - mem->start) >> IO_TLB_SHIFT;
	phys_addr_t orig_addr = mem->slots[index].orig_addr;
	size_t alloc_size = mem->slots[index].alloc_size;
	unsigned long pfn = PFN_DOWN(orig_addr);
	unsigned char *vaddr = mem->vaddr + tlb_addr - mem->start;
	unsigned int tlb_offset, orig_addr_offset;

	if (orig_addr == INVALID_PHYS_ADDR)
		return;

	tlb_offset = tlb_addr & (IO_TLB_SIZE - 1);
	orig_addr_offset = swiotlb_align_offset(dev, orig_addr);
	if (tlb_offset < orig_addr_offset) {
		dev_WARN_ONCE(dev, 1,
			"Access before mapping start detected. orig offset %u, requested offset %u.\n",
			orig_addr_offset, tlb_offset);
		return;
	}

	tlb_offset -= orig_addr_offset;
	if (tlb_offset > alloc_size) {
		dev_WARN_ONCE(dev, 1,
			"Buffer overflow detected. Allocation size: %zu. Mapping size: %zu+%u.\n",
			alloc_size, size, tlb_offset);
		return;
	}

	orig_addr += tlb_offset;
	alloc_size -= tlb_offset;

	if (size > alloc_size) {
		dev_WARN_ONCE(dev, 1,
			"Buffer overflow detected. Allocation size: %zu. Mapping size: %zu.\n",
			alloc_size, size);
		size = alloc_size;
	}

	if (PageHighMem(pfn_to_page(pfn))) {
		 
		unsigned int offset = orig_addr & ~PAGE_MASK;
		char *buffer;
		unsigned int sz = 0;
		unsigned long flags;

		while (size) {
			sz = min_t(size_t, PAGE_SIZE - offset, size);

			local_irq_save(flags);
			buffer = kmap_atomic(pfn_to_page(pfn));
			if (dir == DMA_TO_DEVICE)
				memcpy(vaddr, buffer + offset, sz);
			else
				memcpy(buffer + offset, vaddr, sz);
			kunmap_atomic(buffer);
			local_irq_restore(flags);

			size -= sz;
			pfn++;
			vaddr += sz;
			offset = 0;
		}
	} else if (dir == DMA_TO_DEVICE) {
		memcpy(vaddr, phys_to_virt(orig_addr), size);
	} else {
		memcpy(phys_to_virt(orig_addr), vaddr, size);
	}
}