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6#include <linux/io.h>
7#include <linux/slab.h>
8#include <linux/kernel.h>
9#include <linux/module.h>
10#include <linux/dma-mapping.h>
11
12struct dma_coherent_mem {
13 void *virt_base;
14 dma_addr_t device_base;
15 unsigned long pfn_base;
16 int size;
17 unsigned long *bitmap;
18 spinlock_t spinlock;
19 bool use_dev_dma_pfn_offset;
20};
21
22static struct dma_coherent_mem *dma_coherent_default_memory __ro_after_init;
23
24static inline struct dma_coherent_mem *dev_get_coherent_memory(struct device *dev)
25{
26 if (dev && dev->dma_mem)
27 return dev->dma_mem;
28 return NULL;
29}
30
31static inline dma_addr_t dma_get_device_base(struct device *dev,
32 struct dma_coherent_mem * mem)
33{
34 if (mem->use_dev_dma_pfn_offset)
35 return (mem->pfn_base - dev->dma_pfn_offset) << PAGE_SHIFT;
36 else
37 return mem->device_base;
38}
39
40static int dma_init_coherent_memory(phys_addr_t phys_addr,
41 dma_addr_t device_addr, size_t size,
42 struct dma_coherent_mem **mem)
43{
44 struct dma_coherent_mem *dma_mem = NULL;
45 void *mem_base = NULL;
46 int pages = size >> PAGE_SHIFT;
47 int bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);
48 int ret;
49
50 if (!size) {
51 ret = -EINVAL;
52 goto out;
53 }
54
55 mem_base = memremap(phys_addr, size, MEMREMAP_WC);
56 if (!mem_base) {
57 ret = -EINVAL;
58 goto out;
59 }
60 dma_mem = kzalloc(sizeof(struct dma_coherent_mem), GFP_KERNEL);
61 if (!dma_mem) {
62 ret = -ENOMEM;
63 goto out;
64 }
65 dma_mem->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
66 if (!dma_mem->bitmap) {
67 ret = -ENOMEM;
68 goto out;
69 }
70
71 dma_mem->virt_base = mem_base;
72 dma_mem->device_base = device_addr;
73 dma_mem->pfn_base = PFN_DOWN(phys_addr);
74 dma_mem->size = pages;
75 spin_lock_init(&dma_mem->spinlock);
76
77 *mem = dma_mem;
78 return 0;
79
80out:
81 kfree(dma_mem);
82 if (mem_base)
83 memunmap(mem_base);
84 return ret;
85}
86
87static void dma_release_coherent_memory(struct dma_coherent_mem *mem)
88{
89 if (!mem)
90 return;
91
92 memunmap(mem->virt_base);
93 kfree(mem->bitmap);
94 kfree(mem);
95}
96
97static int dma_assign_coherent_memory(struct device *dev,
98 struct dma_coherent_mem *mem)
99{
100 if (!dev)
101 return -ENODEV;
102
103 if (dev->dma_mem)
104 return -EBUSY;
105
106 dev->dma_mem = mem;
107 return 0;
108}
109
110int dma_declare_coherent_memory(struct device *dev, phys_addr_t phys_addr,
111 dma_addr_t device_addr, size_t size)
112{
113 struct dma_coherent_mem *mem;
114 int ret;
115
116 ret = dma_init_coherent_memory(phys_addr, device_addr, size, &mem);
117 if (ret)
118 return ret;
119
120 ret = dma_assign_coherent_memory(dev, mem);
121 if (ret)
122 dma_release_coherent_memory(mem);
123 return ret;
124}
125EXPORT_SYMBOL(dma_declare_coherent_memory);
126
127void dma_release_declared_memory(struct device *dev)
128{
129 struct dma_coherent_mem *mem = dev->dma_mem;
130
131 if (!mem)
132 return;
133 dma_release_coherent_memory(mem);
134 dev->dma_mem = NULL;
135}
136EXPORT_SYMBOL(dma_release_declared_memory);
137
138static void *__dma_alloc_from_coherent(struct dma_coherent_mem *mem,
139 ssize_t size, dma_addr_t *dma_handle)
140{
141 int order = get_order(size);
142 unsigned long flags;
143 int pageno;
144 void *ret;
145
146 spin_lock_irqsave(&mem->spinlock, flags);
147
148 if (unlikely(size > (mem->size << PAGE_SHIFT)))
149 goto err;
150
151 pageno = bitmap_find_free_region(mem->bitmap, mem->size, order);
152 if (unlikely(pageno < 0))
153 goto err;
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157
158 *dma_handle = mem->device_base + (pageno << PAGE_SHIFT);
159 ret = mem->virt_base + (pageno << PAGE_SHIFT);
160 spin_unlock_irqrestore(&mem->spinlock, flags);
161 memset(ret, 0, size);
162 return ret;
163err:
164 spin_unlock_irqrestore(&mem->spinlock, flags);
165 return NULL;
166}
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182int dma_alloc_from_dev_coherent(struct device *dev, ssize_t size,
183 dma_addr_t *dma_handle, void **ret)
184{
185 struct dma_coherent_mem *mem = dev_get_coherent_memory(dev);
186
187 if (!mem)
188 return 0;
189
190 *ret = __dma_alloc_from_coherent(mem, size, dma_handle);
191 return 1;
192}
193
194void *dma_alloc_from_global_coherent(ssize_t size, dma_addr_t *dma_handle)
195{
196 if (!dma_coherent_default_memory)
197 return NULL;
198
199 return __dma_alloc_from_coherent(dma_coherent_default_memory, size,
200 dma_handle);
201}
202
203static int __dma_release_from_coherent(struct dma_coherent_mem *mem,
204 int order, void *vaddr)
205{
206 if (mem && vaddr >= mem->virt_base && vaddr <
207 (mem->virt_base + (mem->size << PAGE_SHIFT))) {
208 int page = (vaddr - mem->virt_base) >> PAGE_SHIFT;
209 unsigned long flags;
210
211 spin_lock_irqsave(&mem->spinlock, flags);
212 bitmap_release_region(mem->bitmap, page, order);
213 spin_unlock_irqrestore(&mem->spinlock, flags);
214 return 1;
215 }
216 return 0;
217}
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231int dma_release_from_dev_coherent(struct device *dev, int order, void *vaddr)
232{
233 struct dma_coherent_mem *mem = dev_get_coherent_memory(dev);
234
235 return __dma_release_from_coherent(mem, order, vaddr);
236}
237
238int dma_release_from_global_coherent(int order, void *vaddr)
239{
240 if (!dma_coherent_default_memory)
241 return 0;
242
243 return __dma_release_from_coherent(dma_coherent_default_memory, order,
244 vaddr);
245}
246
247static int __dma_mmap_from_coherent(struct dma_coherent_mem *mem,
248 struct vm_area_struct *vma, void *vaddr, size_t size, int *ret)
249{
250 if (mem && vaddr >= mem->virt_base && vaddr + size <=
251 (mem->virt_base + (mem->size << PAGE_SHIFT))) {
252 unsigned long off = vma->vm_pgoff;
253 int start = (vaddr - mem->virt_base) >> PAGE_SHIFT;
254 int user_count = vma_pages(vma);
255 int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
256
257 *ret = -ENXIO;
258 if (off < count && user_count <= count - off) {
259 unsigned long pfn = mem->pfn_base + start + off;
260 *ret = remap_pfn_range(vma, vma->vm_start, pfn,
261 user_count << PAGE_SHIFT,
262 vma->vm_page_prot);
263 }
264 return 1;
265 }
266 return 0;
267}
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284int dma_mmap_from_dev_coherent(struct device *dev, struct vm_area_struct *vma,
285 void *vaddr, size_t size, int *ret)
286{
287 struct dma_coherent_mem *mem = dev_get_coherent_memory(dev);
288
289 return __dma_mmap_from_coherent(mem, vma, vaddr, size, ret);
290}
291EXPORT_SYMBOL(dma_mmap_from_dev_coherent);
292
293int dma_mmap_from_global_coherent(struct vm_area_struct *vma, void *vaddr,
294 size_t size, int *ret)
295{
296 if (!dma_coherent_default_memory)
297 return 0;
298
299 return __dma_mmap_from_coherent(dma_coherent_default_memory, vma,
300 vaddr, size, ret);
301}
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305
306#ifdef CONFIG_OF_RESERVED_MEM
307#include <linux/of.h>
308#include <linux/of_fdt.h>
309#include <linux/of_reserved_mem.h>
310
311static struct reserved_mem *dma_reserved_default_memory __initdata;
312
313static int rmem_dma_device_init(struct reserved_mem *rmem, struct device *dev)
314{
315 struct dma_coherent_mem *mem = rmem->priv;
316 int ret;
317
318 if (!mem) {
319 ret = dma_init_coherent_memory(rmem->base, rmem->base,
320 rmem->size, &mem);
321 if (ret) {
322 pr_err("Reserved memory: failed to init DMA memory pool at %pa, size %ld MiB\n",
323 &rmem->base, (unsigned long)rmem->size / SZ_1M);
324 return ret;
325 }
326 }
327 mem->use_dev_dma_pfn_offset = true;
328 rmem->priv = mem;
329 dma_assign_coherent_memory(dev, mem);
330 return 0;
331}
332
333static void rmem_dma_device_release(struct reserved_mem *rmem,
334 struct device *dev)
335{
336 if (dev)
337 dev->dma_mem = NULL;
338}
339
340static const struct reserved_mem_ops rmem_dma_ops = {
341 .device_init = rmem_dma_device_init,
342 .device_release = rmem_dma_device_release,
343};
344
345static int __init rmem_dma_setup(struct reserved_mem *rmem)
346{
347 unsigned long node = rmem->fdt_node;
348
349 if (of_get_flat_dt_prop(node, "reusable", NULL))
350 return -EINVAL;
351
352#ifdef CONFIG_ARM
353 if (!of_get_flat_dt_prop(node, "no-map", NULL)) {
354 pr_err("Reserved memory: regions without no-map are not yet supported\n");
355 return -EINVAL;
356 }
357
358 if (of_get_flat_dt_prop(node, "linux,dma-default", NULL)) {
359 WARN(dma_reserved_default_memory,
360 "Reserved memory: region for default DMA coherent area is redefined\n");
361 dma_reserved_default_memory = rmem;
362 }
363#endif
364
365 rmem->ops = &rmem_dma_ops;
366 pr_info("Reserved memory: created DMA memory pool at %pa, size %ld MiB\n",
367 &rmem->base, (unsigned long)rmem->size / SZ_1M);
368 return 0;
369}
370
371static int __init dma_init_reserved_memory(void)
372{
373 const struct reserved_mem_ops *ops;
374 int ret;
375
376 if (!dma_reserved_default_memory)
377 return -ENOMEM;
378
379 ops = dma_reserved_default_memory->ops;
380
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385 ret = ops->device_init(dma_reserved_default_memory, NULL);
386
387 if (!ret) {
388 dma_coherent_default_memory = dma_reserved_default_memory->priv;
389 pr_info("DMA: default coherent area is set\n");
390 }
391
392 return ret;
393}
394
395core_initcall(dma_init_reserved_memory);
396
397RESERVEDMEM_OF_DECLARE(dma, "shared-dma-pool", rmem_dma_setup);
398#endif
399