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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
169 if (!dev)
170 return 0;
171 mem = dev->dma_mem;
172 if (!mem)
173 return 0;
174
175 *ret = NULL;
176 spin_lock_irqsave(&mem->spinlock, flags);
177
178 if (unlikely(size > (mem->size << PAGE_SHIFT)))
179 goto err;
180
181 pageno = bitmap_find_free_region(mem->bitmap, mem->size, order);
182 if (unlikely(pageno < 0))
183 goto err;
184
185 /*
186 * Memory was found in the per-device area.
187 */
188 *dma_handle = mem->device_base + (pageno << PAGE_SHIFT);
189 *ret = mem->virt_base + (pageno << PAGE_SHIFT);
190 if (mem->flags & DMA_MEMORY_MAP)
191 memset(*ret, 0, size);
192 else
193 memset_io(*ret, 0, size);
194 spin_unlock_irqrestore(&mem->spinlock, flags);
195
196 return 1;
197
198err:
199 spin_unlock_irqrestore(&mem->spinlock, flags);
200 /*
201 * In the case where the allocation can not be satisfied from the
202 * per-device area, try to fall back to generic memory if the
203 * constraints allow it.
204 */
205 return mem->flags & DMA_MEMORY_EXCLUSIVE;
206}
207EXPORT_SYMBOL(dma_alloc_from_coherent);
208
209/**
210 * dma_release_from_coherent() - try to free the memory allocated from per-device coherent memory pool
211 * @dev: device from which the memory was allocated
212 * @order: the order of pages allocated
213 * @vaddr: virtual address of allocated pages
214 *
215 * This checks whether the memory was allocated from the per-device
216 * coherent memory pool and if so, releases that memory.
217 *
218 * Returns 1 if we correctly released the memory, or 0 if
219 * dma_release_coherent() should proceed with releasing memory from
220 * generic pools.
221 */
222int dma_release_from_coherent(struct device *dev, int order, void *vaddr)
223{
224 struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
225
226 if (mem && vaddr >= mem->virt_base && vaddr <
227 (mem->virt_base + (mem->size << PAGE_SHIFT))) {
228 int page = (vaddr - mem->virt_base) >> PAGE_SHIFT;
229 unsigned long flags;
230
231 spin_lock_irqsave(&mem->spinlock, flags);
232 bitmap_release_region(mem->bitmap, page, order);
233 spin_unlock_irqrestore(&mem->spinlock, flags);
234 return 1;
235 }
236 return 0;
237}
238EXPORT_SYMBOL(dma_release_from_coherent);
239
240/**
241 * dma_mmap_from_coherent() - try to mmap the memory allocated from
242 * per-device coherent memory pool to userspace
243 * @dev: device from which the memory was allocated
244 * @vma: vm_area for the userspace memory
245 * @vaddr: cpu address returned by dma_alloc_from_coherent
246 * @size: size of the memory buffer allocated by dma_alloc_from_coherent
247 * @ret: result from remap_pfn_range()
248 *
249 * This checks whether the memory was allocated from the per-device
250 * coherent memory pool and if so, maps that memory to the provided vma.
251 *
252 * Returns 1 if we correctly mapped the memory, or 0 if the caller should
253 * proceed with mapping memory from generic pools.
254 */
255int dma_mmap_from_coherent(struct device *dev, struct vm_area_struct *vma,
256 void *vaddr, size_t size, int *ret)
257{
258 struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
259
260 if (mem && vaddr >= mem->virt_base && vaddr + size <=
261 (mem->virt_base + (mem->size << PAGE_SHIFT))) {
262 unsigned long off = vma->vm_pgoff;
263 int start = (vaddr - mem->virt_base) >> PAGE_SHIFT;
264 int user_count = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
265 int count = size >> PAGE_SHIFT;
266
267 *ret = -ENXIO;
268 if (off < count && user_count <= count - off) {
269 unsigned long pfn = mem->pfn_base + start + off;
270 *ret = remap_pfn_range(vma, vma->vm_start, pfn,
271 user_count << PAGE_SHIFT,
272 vma->vm_page_prot);
273 }
274 return 1;
275 }
276 return 0;
277}
278EXPORT_SYMBOL(dma_mmap_from_coherent);
279
280/*
281 * Support for reserved memory regions defined in device tree
282 */
283#ifdef CONFIG_OF_RESERVED_MEM
284#include <linux/of.h>
285#include <linux/of_fdt.h>
286#include <linux/of_reserved_mem.h>
287
288static int rmem_dma_device_init(struct reserved_mem *rmem, struct device *dev)
289{
290 struct dma_coherent_mem *mem = rmem->priv;
291
292 if (!mem &&
293 !dma_init_coherent_memory(rmem->base, rmem->base, rmem->size,
294 DMA_MEMORY_MAP | DMA_MEMORY_EXCLUSIVE,
295 &mem)) {
296 pr_err("Reserved memory: failed to init DMA memory pool at %pa, size %ld MiB\n",
297 &rmem->base, (unsigned long)rmem->size / SZ_1M);
298 return -ENODEV;
299 }
300 rmem->priv = mem;
301 dma_assign_coherent_memory(dev, mem);
302 return 0;
303}
304
305static void rmem_dma_device_release(struct reserved_mem *rmem,
306 struct device *dev)
307{
308 dev->dma_mem = NULL;
309}
310
311static const struct reserved_mem_ops rmem_dma_ops = {
312 .device_init = rmem_dma_device_init,
313 .device_release = rmem_dma_device_release,
314};
315
316static int __init rmem_dma_setup(struct reserved_mem *rmem)
317{
318 unsigned long node = rmem->fdt_node;
319
320 if (of_get_flat_dt_prop(node, "reusable", NULL))
321 return -EINVAL;
322
323#ifdef CONFIG_ARM
324 if (!of_get_flat_dt_prop(node, "no-map", NULL)) {
325 pr_err("Reserved memory: regions without no-map are not yet supported\n");
326 return -EINVAL;
327 }
328#endif
329
330 rmem->ops = &rmem_dma_ops;
331 pr_info("Reserved memory: created DMA memory pool at %pa, size %ld MiB\n",
332 &rmem->base, (unsigned long)rmem->size / SZ_1M);
333 return 0;
334}
335RESERVEDMEM_OF_DECLARE(dma, "shared-dma-pool", rmem_dma_setup);
336#endif