1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 *  PowerPC version derived from arch/arm/mm/consistent.c
4 *    Copyright (C) 2001 Dan Malek (dmalek@jlc.net)
5 *
6 *  Copyright (C) 2000 Russell King
7 */
8
9#include <linux/kernel.h>
10#include <linux/errno.h>
11#include <linux/types.h>
12#include <linux/highmem.h>
13#include <linux/dma-direct.h>
14#include <linux/dma-map-ops.h>
15
16#include <asm/tlbflush.h>
17#include <asm/dma.h>
18
19/*
20 * make an area consistent.
21 */
22static void __dma_sync(void *vaddr, size_t size, int direction)
23{
24	unsigned long start = (unsigned long)vaddr;
25	unsigned long end   = start + size;
26
27	switch (direction) {
28	case DMA_NONE:
29		BUG();
30	case DMA_FROM_DEVICE:
31		/*
32		 * invalidate only when cache-line aligned otherwise there is
33		 * the potential for discarding uncommitted data from the cache
34		 */
35		if ((start | end) & (L1_CACHE_BYTES - 1))
36			flush_dcache_range(start, end);
37		else
38			invalidate_dcache_range(start, end);
39		break;
40	case DMA_TO_DEVICE:		/* writeback only */
41		clean_dcache_range(start, end);
42		break;
43	case DMA_BIDIRECTIONAL:	/* writeback and invalidate */
44		flush_dcache_range(start, end);
45		break;
46	}
47}
48
49#ifdef CONFIG_HIGHMEM
50/*
51 * __dma_sync_page() implementation for systems using highmem.
52 * In this case, each page of a buffer must be kmapped/kunmapped
53 * in order to have a virtual address for __dma_sync(). This must
54 * not sleep so kmap_atomic()/kunmap_atomic() are used.
55 *
56 * Note: yes, it is possible and correct to have a buffer extend
57 * beyond the first page.
58 */
59static inline void __dma_sync_page_highmem(struct page *page,
60		unsigned long offset, size_t size, int direction)
61{
62	size_t seg_size = min((size_t)(PAGE_SIZE - offset), size);
63	size_t cur_size = seg_size;
64	unsigned long flags, start, seg_offset = offset;
65	int nr_segs = 1 + ((size - seg_size) + PAGE_SIZE - 1)/PAGE_SIZE;
66	int seg_nr = 0;
67
68	local_irq_save(flags);
69
70	do {
71		start = (unsigned long)kmap_atomic(page + seg_nr) + seg_offset;
72
73		/* Sync this buffer segment */
74		__dma_sync((void *)start, seg_size, direction);
75		kunmap_atomic((void *)start);
76		seg_nr++;
77
78		/* Calculate next buffer segment size */
79		seg_size = min((size_t)PAGE_SIZE, size - cur_size);
80
81		/* Add the segment size to our running total */
82		cur_size += seg_size;
83		seg_offset = 0;
84	} while (seg_nr < nr_segs);
85
86	local_irq_restore(flags);
87}
88#endif /* CONFIG_HIGHMEM */
89
90/*
91 * __dma_sync_page makes memory consistent. identical to __dma_sync, but
92 * takes a struct page instead of a virtual address
93 */
94static void __dma_sync_page(phys_addr_t paddr, size_t size, int dir)
95{
96	struct page *page = pfn_to_page(paddr >> PAGE_SHIFT);
97	unsigned offset = paddr & ~PAGE_MASK;
98
99#ifdef CONFIG_HIGHMEM
100	__dma_sync_page_highmem(page, offset, size, dir);
101#else
102	unsigned long start = (unsigned long)page_address(page) + offset;
103	__dma_sync((void *)start, size, dir);
104#endif
105}
106
107void arch_sync_dma_for_device(phys_addr_t paddr, size_t size,
108		enum dma_data_direction dir)
109{
110	__dma_sync_page(paddr, size, dir);
111}
112
113void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size,
114		enum dma_data_direction dir)
115{
116	__dma_sync_page(paddr, size, dir);
117}
118
119void arch_dma_prep_coherent(struct page *page, size_t size)
120{
121	unsigned long kaddr = (unsigned long)page_address(page);
122
123	flush_dcache_range(kaddr, kaddr + size);
124}
125