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linux/arch/nds32/kernel/dma.c
Christoph Hellwig 9f4df96b87 dma-mapping: merge <linux/dma-noncoherent.h> into <linux/dma-map-ops.h>
Move more nitty gritty DMA implementation details into the common
internal header.

Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-10-06 07:07:06 +02:00

83 lines
1.7 KiB
C

// SPDX-License-Identifier: GPL-2.0
// Copyright (C) 2005-2017 Andes Technology Corporation
#include <linux/types.h>
#include <linux/mm.h>
#include <linux/dma-map-ops.h>
#include <linux/cache.h>
#include <linux/highmem.h>
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
#include <asm/proc-fns.h>
static inline void cache_op(phys_addr_t paddr, size_t size,
void (*fn)(unsigned long start, unsigned long end))
{
struct page *page = pfn_to_page(paddr >> PAGE_SHIFT);
unsigned offset = paddr & ~PAGE_MASK;
size_t left = size;
unsigned long start;
do {
size_t len = left;
if (PageHighMem(page)) {
void *addr;
if (offset + len > PAGE_SIZE) {
if (offset >= PAGE_SIZE) {
page += offset >> PAGE_SHIFT;
offset &= ~PAGE_MASK;
}
len = PAGE_SIZE - offset;
}
addr = kmap_atomic(page);
start = (unsigned long)(addr + offset);
fn(start, start + len);
kunmap_atomic(addr);
} else {
start = (unsigned long)phys_to_virt(paddr);
fn(start, start + size);
}
offset = 0;
page++;
left -= len;
} while (left);
}
void arch_sync_dma_for_device(phys_addr_t paddr, size_t size,
enum dma_data_direction dir)
{
switch (dir) {
case DMA_FROM_DEVICE:
break;
case DMA_TO_DEVICE:
case DMA_BIDIRECTIONAL:
cache_op(paddr, size, cpu_dma_wb_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:
break;
case DMA_FROM_DEVICE:
case DMA_BIDIRECTIONAL:
cache_op(paddr, size, cpu_dma_inval_range);
break;
default:
BUG();
}
}
void arch_dma_prep_coherent(struct page *page, size_t size)
{
cache_op(page_to_phys(page), size, cpu_dma_wbinval_range);
}