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/arch/xtensa/kernel/pci-dma.c

http://github.com/mirrors/linux
C | 99 lines | 70 code | 12 blank | 17 comment | 5 complexity | ed2f5dfdf7573e67b26ebe784a930b58 MD5 | raw file
 1// SPDX-License-Identifier: GPL-2.0-or-later
 2/*
 3 * DMA coherent memory allocation.
 4 *
 5 * Copyright (C) 2002 - 2005 Tensilica Inc.
 6 * Copyright (C) 2015 Cadence Design Systems Inc.
 7 *
 8 * Based on version for i386.
 9 *
10 * Chris Zankel <chris@zankel.net>
11 * Joe Taylor <joe@tensilica.com, joetylr@yahoo.com>
12 */
13
14#include <linux/dma-contiguous.h>
15#include <linux/dma-noncoherent.h>
16#include <linux/dma-direct.h>
17#include <linux/gfp.h>
18#include <linux/highmem.h>
19#include <linux/mm.h>
20#include <linux/types.h>
21#include <asm/cacheflush.h>
22#include <asm/io.h>
23#include <asm/platform.h>
24
25static void do_cache_op(phys_addr_t paddr, size_t size,
26			void (*fn)(unsigned long, unsigned long))
27{
28	unsigned long off = paddr & (PAGE_SIZE - 1);
29	unsigned long pfn = PFN_DOWN(paddr);
30	struct page *page = pfn_to_page(pfn);
31
32	if (!PageHighMem(page))
33		fn((unsigned long)phys_to_virt(paddr), size);
34	else
35		while (size > 0) {
36			size_t sz = min_t(size_t, size, PAGE_SIZE - off);
37			void *vaddr = kmap_atomic(page);
38
39			fn((unsigned long)vaddr + off, sz);
40			kunmap_atomic(vaddr);
41			off = 0;
42			++page;
43			size -= sz;
44		}
45}
46
47void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size,
48		enum dma_data_direction dir)
49{
50	switch (dir) {
51	case DMA_BIDIRECTIONAL:
52	case DMA_FROM_DEVICE:
53		do_cache_op(paddr, size, __invalidate_dcache_range);
54		break;
55
56	case DMA_NONE:
57		BUG();
58		break;
59
60	default:
61		break;
62	}
63}
64
65void arch_sync_dma_for_device(phys_addr_t paddr, size_t size,
66		enum dma_data_direction dir)
67{
68	switch (dir) {
69	case DMA_BIDIRECTIONAL:
70	case DMA_TO_DEVICE:
71		if (XCHAL_DCACHE_IS_WRITEBACK)
72			do_cache_op(paddr, size, __flush_dcache_range);
73		break;
74
75	case DMA_NONE:
76		BUG();
77		break;
78
79	default:
80		break;
81	}
82}
83
84void arch_dma_prep_coherent(struct page *page, size_t size)
85{
86	__invalidate_dcache_range((unsigned long)page_address(page), size);
87}
88
89/*
90 * Memory caching is platform-dependent in noMMU xtensa configurations.
91 * This function should be implemented in platform code in order to enable
92 * coherent DMA memory operations when CONFIG_MMU is not enabled.
93 */
94#ifdef CONFIG_MMU
95void *arch_dma_set_uncached(void *p, size_t size)
96{
97	return p + XCHAL_KSEG_BYPASS_VADDR - XCHAL_KSEG_CACHED_VADDR;
98}
99#endif /* CONFIG_MMU */