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1/*
2 * Coherent per-device memory handling.
3 * Borrowed from i386
4 */
5#include <linux/slab.h>
6#include <linux/kernel.h>
7#include <linux/dma-mapping.h>
8
9struct dma_coherent_mem {
10 void *virt_base;
11 dma_addr_t device_base;
12 int size;
13 int flags;
14 unsigned long *bitmap;
15};
16
17int dma_declare_coherent_memory(struct device *dev, dma_addr_t bus_addr,
18 dma_addr_t device_addr, size_t size, int flags)
19{
20 void __iomem *mem_base = NULL;
21 int pages = size >> PAGE_SHIFT;
22 int bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);
23
24 if ((flags & (DMA_MEMORY_MAP | DMA_MEMORY_IO)) == 0)
25 goto out;
26 if (!size)
27 goto out;
28 if (dev->dma_mem)
29 goto out;
30
31 /* FIXME: this routine just ignores DMA_MEMORY_INCLUDES_CHILDREN */
32
33 mem_base = ioremap(bus_addr, size);
34 if (!mem_base)
35 goto out;
36
37 dev->dma_mem = kzalloc(sizeof(struct dma_coherent_mem), GFP_KERNEL);
38 if (!dev->dma_mem)
39 goto out;
40 dev->dma_mem->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
41 if (!dev->dma_mem->bitmap)
42 goto free1_out;
43
44 dev->dma_mem->virt_base = mem_base;
45 dev->dma_mem->device_base = device_addr;
46 dev->dma_mem->size = pages;
47 dev->dma_mem->flags = flags;
48
49 if (flags & DMA_MEMORY_MAP)
50 return DMA_MEMORY_MAP;
51
52 return DMA_MEMORY_IO;
53
54 free1_out:
55 kfree(dev->dma_mem);
56 out:
57 if (mem_base)
58 iounmap(mem_base);
59 return 0;
60}
61EXPORT_SYMBOL(dma_declare_coherent_memory);
62
63void dma_release_declared_memory(struct device *dev)
64{
65 struct dma_coherent_mem *mem = dev->dma_mem;
66
67 if (!mem)
68 return;
69 dev->dma_mem = NULL;
70 iounmap(mem->virt_base);
71 kfree(mem->bitmap);
72 kfree(mem);
73}
74EXPORT_SYMBOL(dma_release_declared_memory);
75
76void *dma_mark_declared_memory_occupied(struct device *dev,
77 dma_addr_t device_addr, size_t size)
78{
79 struct dma_coherent_mem *mem = dev->dma_mem;
80 int pos, err;
81
82 size += device_addr & ~PAGE_MASK;
83
84 if (!mem)
85 return ERR_PTR(-EINVAL);
86
87 pos = (device_addr - mem->device_base) >> PAGE_SHIFT;
88 err = bitmap_allocate_region(mem->bitmap, pos, get_order(size));
89 if (err != 0)
90 return ERR_PTR(err);
91 return mem->virt_base + (pos << PAGE_SHIFT);
92}
93EXPORT_SYMBOL(dma_mark_declared_memory_occupied);
94
95/**
96 * dma_alloc_from_coherent() - try to allocate memory from the per-device coherent area
97 *
98 * @dev: device from which we allocate memory
99 * @size: size of requested memory area
100 * @dma_handle: This will be filled with the correct dma handle
101 * @ret: This pointer will be filled with the virtual address
102 * to allocated area.
103 *
104 * This function should be only called from per-arch dma_alloc_coherent()
105 * to support allocation from per-device coherent memory pools.
106 *
107 * Returns 0 if dma_alloc_coherent should continue with allocating from
108 * generic memory areas, or !0 if dma_alloc_coherent should return @ret.
109 */
110int dma_alloc_from_coherent(struct device *dev, ssize_t size,
111 dma_addr_t *dma_handle, void **ret)
112{
113 struct dma_coherent_mem *mem;
114 int order = get_order(size);
115 int pageno;
116
117 if (!dev)
118 return 0;
119 mem = dev->dma_mem;
120 if (!mem)
121 return 0;
122
123 *ret = NULL;
124
125 if (unlikely(size > (mem->size << PAGE_SHIFT)))
126 goto err;
127
128 pageno = bitmap_find_free_region(mem->bitmap, mem->size, order);
129 if (unlikely(pageno < 0))
130 goto err;
131
132 /*
133 * Memory was found in the per-device area.
134 */
135 *dma_handle = mem->device_base + (pageno << PAGE_SHIFT);
136 *ret = mem->virt_base + (pageno << PAGE_SHIFT);
137 memset(*ret, 0, size);
138
139 return 1;
140
141err:
142 /*
143 * In the case where the allocation can not be satisfied from the
144 * per-device area, try to fall back to generic memory if the
145 * constraints allow it.
146 */
147 return mem->flags & DMA_MEMORY_EXCLUSIVE;
148}
149EXPORT_SYMBOL(dma_alloc_from_coherent);
150
151/**
152 * dma_release_from_coherent() - try to free the memory allocated from per-device coherent memory pool
153 * @dev: device from which the memory was allocated
154 * @order: the order of pages allocated
155 * @vaddr: virtual address of allocated pages
156 *
157 * This checks whether the memory was allocated from the per-device
158 * coherent memory pool and if so, releases that memory.
159 *
160 * Returns 1 if we correctly released the memory, or 0 if
161 * dma_release_coherent() should proceed with releasing memory from
162 * generic pools.
163 */
164int dma_release_from_coherent(struct device *dev, int order, void *vaddr)
165{
166 struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
167
168 if (mem && vaddr >= mem->virt_base && vaddr <
169 (mem->virt_base + (mem->size << PAGE_SHIFT))) {
170 int page = (vaddr - mem->virt_base) >> PAGE_SHIFT;
171
172 bitmap_release_region(mem->bitmap, page, order);
173 return 1;
174 }
175 return 0;
176}
177EXPORT_SYMBOL(dma_release_from_coherent);
1/*
2 * Coherent per-device memory handling.
3 * Borrowed from i386
4 */
5#include <linux/io.h>
6#include <linux/slab.h>
7#include <linux/kernel.h>
8#include <linux/module.h>
9#include <linux/dma-mapping.h>
10
11struct dma_coherent_mem {
12 void *virt_base;
13 dma_addr_t device_base;
14 unsigned long pfn_base;
15 int size;
16 int flags;
17 unsigned long *bitmap;
18 spinlock_t spinlock;
19};
20
21static bool dma_init_coherent_memory(
22 phys_addr_t phys_addr, dma_addr_t device_addr, size_t size, int flags,
23 struct dma_coherent_mem **mem)
24{
25 struct dma_coherent_mem *dma_mem = NULL;
26 void __iomem *mem_base = NULL;
27 int pages = size >> PAGE_SHIFT;
28 int bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);
29
30 if ((flags & (DMA_MEMORY_MAP | DMA_MEMORY_IO)) == 0)
31 goto out;
32 if (!size)
33 goto out;
34
35 if (flags & DMA_MEMORY_MAP)
36 mem_base = memremap(phys_addr, size, MEMREMAP_WC);
37 else
38 mem_base = ioremap(phys_addr, size);
39 if (!mem_base)
40 goto out;
41
42 dma_mem = kzalloc(sizeof(struct dma_coherent_mem), GFP_KERNEL);
43 if (!dma_mem)
44 goto out;
45 dma_mem->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
46 if (!dma_mem->bitmap)
47 goto out;
48
49 dma_mem->virt_base = mem_base;
50 dma_mem->device_base = device_addr;
51 dma_mem->pfn_base = PFN_DOWN(phys_addr);
52 dma_mem->size = pages;
53 dma_mem->flags = flags;
54 spin_lock_init(&dma_mem->spinlock);
55
56 *mem = dma_mem;
57 return true;
58
59out:
60 kfree(dma_mem);
61 if (mem_base) {
62 if (flags & DMA_MEMORY_MAP)
63 memunmap(mem_base);
64 else
65 iounmap(mem_base);
66 }
67 return false;
68}
69
70static void dma_release_coherent_memory(struct dma_coherent_mem *mem)
71{
72 if (!mem)
73 return;
74
75 if (mem->flags & DMA_MEMORY_MAP)
76 memunmap(mem->virt_base);
77 else
78 iounmap(mem->virt_base);
79 kfree(mem->bitmap);
80 kfree(mem);
81}
82
83static int dma_assign_coherent_memory(struct device *dev,
84 struct dma_coherent_mem *mem)
85{
86 if (dev->dma_mem)
87 return -EBUSY;
88
89 dev->dma_mem = mem;
90 /* FIXME: this routine just ignores DMA_MEMORY_INCLUDES_CHILDREN */
91
92 return 0;
93}
94
95int dma_declare_coherent_memory(struct device *dev, phys_addr_t phys_addr,
96 dma_addr_t device_addr, size_t size, int flags)
97{
98 struct dma_coherent_mem *mem;
99
100 if (!dma_init_coherent_memory(phys_addr, device_addr, size, flags,
101 &mem))
102 return 0;
103
104 if (dma_assign_coherent_memory(dev, mem) == 0)
105 return flags & DMA_MEMORY_MAP ? DMA_MEMORY_MAP : DMA_MEMORY_IO;
106
107 dma_release_coherent_memory(mem);
108 return 0;
109}
110EXPORT_SYMBOL(dma_declare_coherent_memory);
111
112void dma_release_declared_memory(struct device *dev)
113{
114 struct dma_coherent_mem *mem = dev->dma_mem;
115
116 if (!mem)
117 return;
118 dma_release_coherent_memory(mem);
119 dev->dma_mem = NULL;
120}
121EXPORT_SYMBOL(dma_release_declared_memory);
122
123void *dma_mark_declared_memory_occupied(struct device *dev,
124 dma_addr_t device_addr, size_t size)
125{
126 struct dma_coherent_mem *mem = dev->dma_mem;
127 unsigned long flags;
128 int pos, err;
129
130 size += device_addr & ~PAGE_MASK;
131
132 if (!mem)
133 return ERR_PTR(-EINVAL);
134
135 spin_lock_irqsave(&mem->spinlock, flags);
136 pos = (device_addr - mem->device_base) >> PAGE_SHIFT;
137 err = bitmap_allocate_region(mem->bitmap, pos, get_order(size));
138 spin_unlock_irqrestore(&mem->spinlock, flags);
139
140 if (err != 0)
141 return ERR_PTR(err);
142 return mem->virt_base + (pos << PAGE_SHIFT);
143}
144EXPORT_SYMBOL(dma_mark_declared_memory_occupied);
145
146/**
147 * dma_alloc_from_coherent() - try to allocate memory from the per-device coherent area
148 *
149 * @dev: device from which we allocate memory
150 * @size: size of requested memory area
151 * @dma_handle: This will be filled with the correct dma handle
152 * @ret: This pointer will be filled with the virtual address
153 * to allocated area.
154 *
155 * This function should be only called from per-arch dma_alloc_coherent()
156 * to support allocation from per-device coherent memory pools.
157 *
158 * Returns 0 if dma_alloc_coherent should continue with allocating from
159 * generic memory areas, or !0 if dma_alloc_coherent should return @ret.
160 */
161int dma_alloc_from_coherent(struct device *dev, ssize_t size,
162 dma_addr_t *dma_handle, void **ret)
163{
164 struct dma_coherent_mem *mem;
165 int order = get_order(size);
166 unsigned long flags;
167 int pageno;
168 int dma_memory_map;
169
170 if (!dev)
171 return 0;
172 mem = dev->dma_mem;
173 if (!mem)
174 return 0;
175
176 *ret = NULL;
177 spin_lock_irqsave(&mem->spinlock, flags);
178
179 if (unlikely(size > (mem->size << PAGE_SHIFT)))
180 goto err;
181
182 pageno = bitmap_find_free_region(mem->bitmap, mem->size, order);
183 if (unlikely(pageno < 0))
184 goto err;
185
186 /*
187 * Memory was found in the per-device area.
188 */
189 *dma_handle = mem->device_base + (pageno << PAGE_SHIFT);
190 *ret = mem->virt_base + (pageno << PAGE_SHIFT);
191 dma_memory_map = (mem->flags & DMA_MEMORY_MAP);
192 spin_unlock_irqrestore(&mem->spinlock, flags);
193 if (dma_memory_map)
194 memset(*ret, 0, size);
195 else
196 memset_io(*ret, 0, size);
197
198 return 1;
199
200err:
201 spin_unlock_irqrestore(&mem->spinlock, flags);
202 /*
203 * In the case where the allocation can not be satisfied from the
204 * per-device area, try to fall back to generic memory if the
205 * constraints allow it.
206 */
207 return mem->flags & DMA_MEMORY_EXCLUSIVE;
208}
209EXPORT_SYMBOL(dma_alloc_from_coherent);
210
211/**
212 * dma_release_from_coherent() - try to free the memory allocated from per-device coherent memory pool
213 * @dev: device from which the memory was allocated
214 * @order: the order of pages allocated
215 * @vaddr: virtual address of allocated pages
216 *
217 * This checks whether the memory was allocated from the per-device
218 * coherent memory pool and if so, releases that memory.
219 *
220 * Returns 1 if we correctly released the memory, or 0 if
221 * dma_release_coherent() should proceed with releasing memory from
222 * generic pools.
223 */
224int dma_release_from_coherent(struct device *dev, int order, void *vaddr)
225{
226 struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
227
228 if (mem && vaddr >= mem->virt_base && vaddr <
229 (mem->virt_base + (mem->size << PAGE_SHIFT))) {
230 int page = (vaddr - mem->virt_base) >> PAGE_SHIFT;
231 unsigned long flags;
232
233 spin_lock_irqsave(&mem->spinlock, flags);
234 bitmap_release_region(mem->bitmap, page, order);
235 spin_unlock_irqrestore(&mem->spinlock, flags);
236 return 1;
237 }
238 return 0;
239}
240EXPORT_SYMBOL(dma_release_from_coherent);
241
242/**
243 * dma_mmap_from_coherent() - try to mmap the memory allocated from
244 * per-device coherent memory pool to userspace
245 * @dev: device from which the memory was allocated
246 * @vma: vm_area for the userspace memory
247 * @vaddr: cpu address returned by dma_alloc_from_coherent
248 * @size: size of the memory buffer allocated by dma_alloc_from_coherent
249 * @ret: result from remap_pfn_range()
250 *
251 * This checks whether the memory was allocated from the per-device
252 * coherent memory pool and if so, maps that memory to the provided vma.
253 *
254 * Returns 1 if we correctly mapped the memory, or 0 if the caller should
255 * proceed with mapping memory from generic pools.
256 */
257int dma_mmap_from_coherent(struct device *dev, struct vm_area_struct *vma,
258 void *vaddr, size_t size, int *ret)
259{
260 struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
261
262 if (mem && vaddr >= mem->virt_base && vaddr + size <=
263 (mem->virt_base + (mem->size << PAGE_SHIFT))) {
264 unsigned long off = vma->vm_pgoff;
265 int start = (vaddr - mem->virt_base) >> PAGE_SHIFT;
266 int user_count = vma_pages(vma);
267 int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
268
269 *ret = -ENXIO;
270 if (off < count && user_count <= count - off) {
271 unsigned long pfn = mem->pfn_base + start + off;
272 *ret = remap_pfn_range(vma, vma->vm_start, pfn,
273 user_count << PAGE_SHIFT,
274 vma->vm_page_prot);
275 }
276 return 1;
277 }
278 return 0;
279}
280EXPORT_SYMBOL(dma_mmap_from_coherent);
281
282/*
283 * Support for reserved memory regions defined in device tree
284 */
285#ifdef CONFIG_OF_RESERVED_MEM
286#include <linux/of.h>
287#include <linux/of_fdt.h>
288#include <linux/of_reserved_mem.h>
289
290static int rmem_dma_device_init(struct reserved_mem *rmem, struct device *dev)
291{
292 struct dma_coherent_mem *mem = rmem->priv;
293
294 if (!mem &&
295 !dma_init_coherent_memory(rmem->base, rmem->base, rmem->size,
296 DMA_MEMORY_MAP | DMA_MEMORY_EXCLUSIVE,
297 &mem)) {
298 pr_err("Reserved memory: failed to init DMA memory pool at %pa, size %ld MiB\n",
299 &rmem->base, (unsigned long)rmem->size / SZ_1M);
300 return -ENODEV;
301 }
302 rmem->priv = mem;
303 dma_assign_coherent_memory(dev, mem);
304 return 0;
305}
306
307static void rmem_dma_device_release(struct reserved_mem *rmem,
308 struct device *dev)
309{
310 dev->dma_mem = NULL;
311}
312
313static const struct reserved_mem_ops rmem_dma_ops = {
314 .device_init = rmem_dma_device_init,
315 .device_release = rmem_dma_device_release,
316};
317
318static int __init rmem_dma_setup(struct reserved_mem *rmem)
319{
320 unsigned long node = rmem->fdt_node;
321
322 if (of_get_flat_dt_prop(node, "reusable", NULL))
323 return -EINVAL;
324
325#ifdef CONFIG_ARM
326 if (!of_get_flat_dt_prop(node, "no-map", NULL)) {
327 pr_err("Reserved memory: regions without no-map are not yet supported\n");
328 return -EINVAL;
329 }
330#endif
331
332 rmem->ops = &rmem_dma_ops;
333 pr_info("Reserved memory: created DMA memory pool at %pa, size %ld MiB\n",
334 &rmem->base, (unsigned long)rmem->size / SZ_1M);
335 return 0;
336}
337RESERVEDMEM_OF_DECLARE(dma, "shared-dma-pool", rmem_dma_setup);
338#endif