arch/csky/mm/dma-mapping.c

Source file repositories/reference/linux-study-clean/arch/csky/mm/dma-mapping.c

File Facts

System
Linux kernel
Corpus path
arch/csky/mm/dma-mapping.c
Extension
.c
Size
1900 bytes
Lines
88
Domain
Architecture Layer
Bucket
arch/csky
Inferred role
Architecture Layer: implementation source
Status
source implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

if (PageHighMem(page)) {
			start = kmap_atomic(page);

			fn((unsigned long)start + offset,
					(unsigned long)start + offset + len);

			kunmap_atomic(start);
		} else {
			fn((unsigned long)start + offset,
					(unsigned long)start + offset + len);
		}
		offset = 0;

		page++;
		start += PAGE_SIZE;
		left -= len;
	} while (left);
}

static void dma_wbinv_set_zero_range(unsigned long start, unsigned long end)
{
	memset((void *)start, 0, end - start);
	dma_wbinv_range(start, end);
}

void arch_dma_prep_coherent(struct page *page, size_t size)
{
	cache_op(page_to_phys(page), size, dma_wbinv_set_zero_range);
}

void arch_sync_dma_for_device(phys_addr_t paddr, size_t size,
		enum dma_data_direction dir)
{
	switch (dir) {
	case DMA_TO_DEVICE:
		cache_op(paddr, size, dma_wb_range);
		break;
	case DMA_FROM_DEVICE:
	case DMA_BIDIRECTIONAL:
		cache_op(paddr, size, dma_wbinv_range);
		break;
	default:
		BUG();
	}
}

void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size,
		enum dma_data_direction dir)
{
	switch (dir) {
	case DMA_TO_DEVICE:
		return;
	case DMA_FROM_DEVICE:
	case DMA_BIDIRECTIONAL:
		cache_op(paddr, size, dma_inv_range);
		break;
	default:
		BUG();
	}
}

Annotation

Implementation Notes