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6#include <linux/dma-direct.h>
7#include <linux/dma-noncoherent.h>
8#include <linux/dma-contiguous.h>
9#include <linux/init.h>
10#include <linux/genalloc.h>
11#include <linux/slab.h>
12#include <linux/vmalloc.h>
13
14struct page **dma_common_find_pages(void *cpu_addr)
15{
16 struct vm_struct *area = find_vm_area(cpu_addr);
17
18 if (!area || area->flags != VM_DMA_COHERENT)
19 return NULL;
20 return area->pages;
21}
22
23static struct vm_struct *__dma_common_pages_remap(struct page **pages,
24 size_t size, pgprot_t prot, const void *caller)
25{
26 struct vm_struct *area;
27
28 area = get_vm_area_caller(size, VM_DMA_COHERENT, caller);
29 if (!area)
30 return NULL;
31
32 if (map_vm_area(area, prot, pages)) {
33 vunmap(area->addr);
34 return NULL;
35 }
36
37 return area;
38}
39
40
41
42
43
44void *dma_common_pages_remap(struct page **pages, size_t size,
45 pgprot_t prot, const void *caller)
46{
47 struct vm_struct *area;
48
49 area = __dma_common_pages_remap(pages, size, prot, caller);
50 if (!area)
51 return NULL;
52
53 area->pages = pages;
54
55 return area->addr;
56}
57
58
59
60
61
62void *dma_common_contiguous_remap(struct page *page, size_t size,
63 pgprot_t prot, const void *caller)
64{
65 int i;
66 struct page **pages;
67 struct vm_struct *area;
68
69 pages = kmalloc(sizeof(struct page *) << get_order(size), GFP_KERNEL);
70 if (!pages)
71 return NULL;
72
73 for (i = 0; i < (size >> PAGE_SHIFT); i++)
74 pages[i] = nth_page(page, i);
75
76 area = __dma_common_pages_remap(pages, size, prot, caller);
77
78 kfree(pages);
79
80 if (!area)
81 return NULL;
82 return area->addr;
83}
84
85
86
87
88void dma_common_free_remap(void *cpu_addr, size_t size)
89{
90 struct vm_struct *area = find_vm_area(cpu_addr);
91
92 if (!area || area->flags != VM_DMA_COHERENT) {
93 WARN(1, "trying to free invalid coherent area: %p\n", cpu_addr);
94 return;
95 }
96
97 unmap_kernel_range((unsigned long)cpu_addr, PAGE_ALIGN(size));
98 vunmap(cpu_addr);
99}
100
101#ifdef CONFIG_DMA_DIRECT_REMAP
102static struct gen_pool *atomic_pool __ro_after_init;
103
104#define DEFAULT_DMA_COHERENT_POOL_SIZE SZ_256K
105static size_t atomic_pool_size __initdata = DEFAULT_DMA_COHERENT_POOL_SIZE;
106
107static int __init early_coherent_pool(char *p)
108{
109 atomic_pool_size = memparse(p, &p);
110 return 0;
111}
112early_param("coherent_pool", early_coherent_pool);
113
114static gfp_t dma_atomic_pool_gfp(void)
115{
116 if (IS_ENABLED(CONFIG_ZONE_DMA))
117 return GFP_DMA;
118 if (IS_ENABLED(CONFIG_ZONE_DMA32))
119 return GFP_DMA32;
120 return GFP_KERNEL;
121}
122
123static int __init dma_atomic_pool_init(void)
124{
125 unsigned int pool_size_order = get_order(atomic_pool_size);
126 unsigned long nr_pages = atomic_pool_size >> PAGE_SHIFT;
127 struct page *page;
128 void *addr;
129 int ret;
130
131 if (dev_get_cma_area(NULL))
132 page = dma_alloc_from_contiguous(NULL, nr_pages,
133 pool_size_order, false);
134 else
135 page = alloc_pages(dma_atomic_pool_gfp(), pool_size_order);
136 if (!page)
137 goto out;
138
139 arch_dma_prep_coherent(page, atomic_pool_size);
140
141 atomic_pool = gen_pool_create(PAGE_SHIFT, -1);
142 if (!atomic_pool)
143 goto free_page;
144
145 addr = dma_common_contiguous_remap(page, atomic_pool_size,
146 pgprot_dmacoherent(PAGE_KERNEL),
147 __builtin_return_address(0));
148 if (!addr)
149 goto destroy_genpool;
150
151 ret = gen_pool_add_virt(atomic_pool, (unsigned long)addr,
152 page_to_phys(page), atomic_pool_size, -1);
153 if (ret)
154 goto remove_mapping;
155 gen_pool_set_algo(atomic_pool, gen_pool_first_fit_order_align, NULL);
156
157 pr_info("DMA: preallocated %zu KiB pool for atomic allocations\n",
158 atomic_pool_size / 1024);
159 return 0;
160
161remove_mapping:
162 dma_common_free_remap(addr, atomic_pool_size);
163destroy_genpool:
164 gen_pool_destroy(atomic_pool);
165 atomic_pool = NULL;
166free_page:
167 if (!dma_release_from_contiguous(NULL, page, nr_pages))
168 __free_pages(page, pool_size_order);
169out:
170 pr_err("DMA: failed to allocate %zu KiB pool for atomic coherent allocation\n",
171 atomic_pool_size / 1024);
172 return -ENOMEM;
173}
174postcore_initcall(dma_atomic_pool_init);
175
176bool dma_in_atomic_pool(void *start, size_t size)
177{
178 if (unlikely(!atomic_pool))
179 return false;
180
181 return gen_pool_has_addr(atomic_pool, (unsigned long)start, size);
182}
183
184void *dma_alloc_from_pool(size_t size, struct page **ret_page, gfp_t flags)
185{
186 unsigned long val;
187 void *ptr = NULL;
188
189 if (!atomic_pool) {
190 WARN(1, "coherent pool not initialised!\n");
191 return NULL;
192 }
193
194 val = gen_pool_alloc(atomic_pool, size);
195 if (val) {
196 phys_addr_t phys = gen_pool_virt_to_phys(atomic_pool, val);
197
198 *ret_page = pfn_to_page(__phys_to_pfn(phys));
199 ptr = (void *)val;
200 memset(ptr, 0, size);
201 }
202
203 return ptr;
204}
205
206bool dma_free_from_pool(void *start, size_t size)
207{
208 if (!dma_in_atomic_pool(start, size))
209 return false;
210 gen_pool_free(atomic_pool, (unsigned long)start, size);
211 return true;
212}
213#endif
214
