Home Home > GIT Browse
summaryrefslogtreecommitdiff
blob: 7a723194ecbed71bec2db5265c932c2f84a8b123 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2012 ARM Ltd.
 * Copyright (c) 2014 The Linux Foundation
 */
#include <linux/dma-direct.h>
#include <linux/dma-noncoherent.h>
#include <linux/dma-contiguous.h>
#include <linux/init.h>
#include <linux/genalloc.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>

static struct vm_struct *__dma_common_pages_remap(struct page **pages,
			size_t size, unsigned long vm_flags, pgprot_t prot,
			const void *caller)
{
	struct vm_struct *area;

	area = get_vm_area_caller(size, vm_flags, caller);
	if (!area)
		return NULL;

	if (map_vm_area(area, prot, pages)) {
		vunmap(area->addr);
		return NULL;
	}

	return area;
}

/*
 * Remaps an array of PAGE_SIZE pages into another vm_area.
 * Cannot be used in non-sleeping contexts
 */
void *dma_common_pages_remap(struct page **pages, size_t size,
			unsigned long vm_flags, pgprot_t prot,
			const void *caller)
{
	struct vm_struct *area;

	area = __dma_common_pages_remap(pages, size, vm_flags, prot, caller);
	if (!area)
		return NULL;

	area->pages = pages;

	return area->addr;
}

/*
 * Remaps an allocated contiguous region into another vm_area.
 * Cannot be used in non-sleeping contexts
 */
void *dma_common_contiguous_remap(struct page *page, size_t size,
			unsigned long vm_flags,
			pgprot_t prot, const void *caller)
{
	int i;
	struct page **pages;
	struct vm_struct *area;

	pages = kmalloc(sizeof(struct page *) << get_order(size), GFP_KERNEL);
	if (!pages)
		return NULL;

	for (i = 0; i < (size >> PAGE_SHIFT); i++)
		pages[i] = nth_page(page, i);

	area = __dma_common_pages_remap(pages, size, vm_flags, prot, caller);

	kfree(pages);

	if (!area)
		return NULL;
	return area->addr;
}

/*
 * Unmaps a range previously mapped by dma_common_*_remap
 */
void dma_common_free_remap(void *cpu_addr, size_t size, unsigned long vm_flags)
{
	struct vm_struct *area = find_vm_area(cpu_addr);

	if (!area || (area->flags & vm_flags) != vm_flags) {
		WARN(1, "trying to free invalid coherent area: %p\n", cpu_addr);
		return;
	}

	unmap_kernel_range((unsigned long)cpu_addr, PAGE_ALIGN(size));
	vunmap(cpu_addr);
}

#ifdef CONFIG_DMA_DIRECT_REMAP
static struct gen_pool *atomic_pool __ro_after_init;

#define DEFAULT_DMA_COHERENT_POOL_SIZE  SZ_256K
static size_t atomic_pool_size __initdata = DEFAULT_DMA_COHERENT_POOL_SIZE;

static int __init early_coherent_pool(char *p)
{
	atomic_pool_size = memparse(p, &p);
	return 0;
}
early_param("coherent_pool", early_coherent_pool);

int __init dma_atomic_pool_init(gfp_t gfp, pgprot_t prot)
{
	unsigned int pool_size_order = get_order(atomic_pool_size);
	unsigned long nr_pages = atomic_pool_size >> PAGE_SHIFT;
	struct page *page;
	void *addr;
	int ret;

	if (dev_get_cma_area(NULL))
		page = dma_alloc_from_contiguous(NULL, nr_pages,
						 pool_size_order, false);
	else
		page = alloc_pages(gfp, pool_size_order);
	if (!page)
		goto out;

	arch_dma_prep_coherent(page, atomic_pool_size);

	atomic_pool = gen_pool_create(PAGE_SHIFT, -1);
	if (!atomic_pool)
		goto free_page;

	addr = dma_common_contiguous_remap(page, atomic_pool_size, VM_USERMAP,
					   prot, __builtin_return_address(0));
	if (!addr)
		goto destroy_genpool;

	ret = gen_pool_add_virt(atomic_pool, (unsigned long)addr,
				page_to_phys(page), atomic_pool_size, -1);
	if (ret)
		goto remove_mapping;
	gen_pool_set_algo(atomic_pool, gen_pool_first_fit_order_align, NULL);

	pr_info("DMA: preallocated %zu KiB pool for atomic allocations\n",
		atomic_pool_size / 1024);
	return 0;

remove_mapping:
	dma_common_free_remap(addr, atomic_pool_size, VM_USERMAP);
destroy_genpool:
	gen_pool_destroy(atomic_pool);
	atomic_pool = NULL;
free_page:
	if (!dma_release_from_contiguous(NULL, page, nr_pages))
		__free_pages(page, pool_size_order);
out:
	pr_err("DMA: failed to allocate %zu KiB pool for atomic coherent allocation\n",
		atomic_pool_size / 1024);
	return -ENOMEM;
}

bool dma_in_atomic_pool(void *start, size_t size)
{
	return addr_in_gen_pool(atomic_pool, (unsigned long)start, size);
}

void *dma_alloc_from_pool(size_t size, struct page **ret_page, gfp_t flags)
{
	unsigned long val;
	void *ptr = NULL;

	if (!atomic_pool) {
		WARN(1, "coherent pool not initialised!\n");
		return NULL;
	}

	val = gen_pool_alloc(atomic_pool, size);
	if (val) {
		phys_addr_t phys = gen_pool_virt_to_phys(atomic_pool, val);

		*ret_page = pfn_to_page(__phys_to_pfn(phys));
		ptr = (void *)val;
		memset(ptr, 0, size);
	}

	return ptr;
}

bool dma_free_from_pool(void *start, size_t size)
{
	if (!dma_in_atomic_pool(start, size))
		return false;
	gen_pool_free(atomic_pool, (unsigned long)start, size);
	return true;
}

void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
		gfp_t flags, unsigned long attrs)
{
	struct page *page = NULL;
	void *ret;

	size = PAGE_ALIGN(size);

	if (!gfpflags_allow_blocking(flags) &&
	    !(attrs & DMA_ATTR_NO_KERNEL_MAPPING)) {
		ret = dma_alloc_from_pool(size, &page, flags);
		if (!ret)
			return NULL;
		goto done;
	}

	page = __dma_direct_alloc_pages(dev, size, dma_handle, flags, attrs);
	if (!page)
		return NULL;

	/* remove any dirty cache lines on the kernel alias */
	arch_dma_prep_coherent(page, size);

	if (attrs & DMA_ATTR_NO_KERNEL_MAPPING) {
		ret = page; /* opaque cookie */
		goto done;
	}

	/* create a coherent mapping */
	ret = dma_common_contiguous_remap(page, size, VM_USERMAP,
			arch_dma_mmap_pgprot(dev, PAGE_KERNEL, attrs),
			__builtin_return_address(0));
	if (!ret) {
		__dma_direct_free_pages(dev, size, page);
		return ret;
	}

	memset(ret, 0, size);
done:
	*dma_handle = phys_to_dma(dev, page_to_phys(page));
	return ret;
}

void arch_dma_free(struct device *dev, size_t size, void *vaddr,
		dma_addr_t dma_handle, unsigned long attrs)
{
	if (attrs & DMA_ATTR_NO_KERNEL_MAPPING) {
		/* vaddr is a struct page cookie, not a kernel address */
		__dma_direct_free_pages(dev, size, vaddr);
	} else if (!dma_free_from_pool(vaddr, PAGE_ALIGN(size))) {
		phys_addr_t phys = dma_to_phys(dev, dma_handle);
		struct page *page = pfn_to_page(__phys_to_pfn(phys));

		vunmap(vaddr);
		__dma_direct_free_pages(dev, size, page);
	}
}

long arch_dma_coherent_to_pfn(struct device *dev, void *cpu_addr,
		dma_addr_t dma_addr)
{
	return __phys_to_pfn(dma_to_phys(dev, dma_addr));
}
#endif /* CONFIG_DMA_DIRECT_REMAP */