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1 | /* |
2 | * Contiguous Memory Allocator for DMA mapping framework | |
3 | * Copyright (c) 2010-2011 by Samsung Electronics. | |
4 | * Written by: | |
5 | * Marek Szyprowski <m.szyprowski@samsung.com> | |
6 | * Michal Nazarewicz <mina86@mina86.com> | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or | |
9 | * modify it under the terms of the GNU General Public License as | |
10 | * published by the Free Software Foundation; either version 2 of the | |
11 | * License or (at your optional) any later version of the license. | |
12 | */ | |
13 | ||
14 | #define pr_fmt(fmt) "cma: " fmt | |
15 | ||
16 | #ifdef CONFIG_CMA_DEBUG | |
17 | #ifndef DEBUG | |
18 | # define DEBUG | |
19 | #endif | |
20 | #endif | |
21 | ||
22 | #include <asm/page.h> | |
23 | #include <asm/dma-contiguous.h> | |
24 | ||
25 | #include <linux/memblock.h> | |
26 | #include <linux/err.h> | |
27 | #include <linux/mm.h> | |
28 | #include <linux/mutex.h> | |
29 | #include <linux/page-isolation.h> | |
30 | #include <linux/slab.h> | |
31 | #include <linux/swap.h> | |
32 | #include <linux/mm_types.h> | |
33 | #include <linux/dma-contiguous.h> | |
34 | ||
35 | #ifndef SZ_1M | |
36 | #define SZ_1M (1 << 20) | |
37 | #endif | |
38 | ||
39 | struct cma { | |
40 | unsigned long base_pfn; | |
41 | unsigned long count; | |
42 | unsigned long *bitmap; | |
43 | }; | |
44 | ||
45 | struct cma *dma_contiguous_default_area; | |
46 | ||
47 | #ifdef CONFIG_CMA_SIZE_MBYTES | |
48 | #define CMA_SIZE_MBYTES CONFIG_CMA_SIZE_MBYTES | |
49 | #else | |
50 | #define CMA_SIZE_MBYTES 0 | |
51 | #endif | |
52 | ||
53 | /* | |
54 | * Default global CMA area size can be defined in kernel's .config. | |
55 | * This is usefull mainly for distro maintainers to create a kernel | |
56 | * that works correctly for most supported systems. | |
57 | * The size can be set in bytes or as a percentage of the total memory | |
58 | * in the system. | |
59 | * | |
60 | * Users, who want to set the size of global CMA area for their system | |
61 | * should use cma= kernel parameter. | |
62 | */ | |
63 | static const unsigned long size_bytes = CMA_SIZE_MBYTES * SZ_1M; | |
64 | static long size_cmdline = -1; | |
65 | ||
66 | static int __init early_cma(char *p) | |
67 | { | |
68 | pr_debug("%s(%s)\n", __func__, p); | |
69 | size_cmdline = memparse(p, &p); | |
70 | return 0; | |
71 | } | |
72 | early_param("cma", early_cma); | |
73 | ||
74 | #ifdef CONFIG_CMA_SIZE_PERCENTAGE | |
75 | ||
76 | static unsigned long __init __maybe_unused cma_early_percent_memory(void) | |
77 | { | |
78 | struct memblock_region *reg; | |
79 | unsigned long total_pages = 0; | |
80 | ||
81 | /* | |
82 | * We cannot use memblock_phys_mem_size() here, because | |
83 | * memblock_analyze() has not been called yet. | |
84 | */ | |
85 | for_each_memblock(memory, reg) | |
86 | total_pages += memblock_region_memory_end_pfn(reg) - | |
87 | memblock_region_memory_base_pfn(reg); | |
88 | ||
89 | return (total_pages * CONFIG_CMA_SIZE_PERCENTAGE / 100) << PAGE_SHIFT; | |
90 | } | |
91 | ||
92 | #else | |
93 | ||
94 | static inline __maybe_unused unsigned long cma_early_percent_memory(void) | |
95 | { | |
96 | return 0; | |
97 | } | |
98 | ||
99 | #endif | |
100 | ||
101 | /** | |
102 | * dma_contiguous_reserve() - reserve area for contiguous memory handling | |
103 | * @limit: End address of the reserved memory (optional, 0 for any). | |
104 | * | |
105 | * This function reserves memory from early allocator. It should be | |
106 | * called by arch specific code once the early allocator (memblock or bootmem) | |
107 | * has been activated and all other subsystems have already allocated/reserved | |
108 | * memory. | |
109 | */ | |
110 | void __init dma_contiguous_reserve(phys_addr_t limit) | |
111 | { | |
112 | unsigned long selected_size = 0; | |
113 | ||
114 | pr_debug("%s(limit %08lx)\n", __func__, (unsigned long)limit); | |
115 | ||
116 | if (size_cmdline != -1) { | |
117 | selected_size = size_cmdline; | |
118 | } else { | |
119 | #ifdef CONFIG_CMA_SIZE_SEL_MBYTES | |
120 | selected_size = size_bytes; | |
121 | #elif defined(CONFIG_CMA_SIZE_SEL_PERCENTAGE) | |
122 | selected_size = cma_early_percent_memory(); | |
123 | #elif defined(CONFIG_CMA_SIZE_SEL_MIN) | |
124 | selected_size = min(size_bytes, cma_early_percent_memory()); | |
125 | #elif defined(CONFIG_CMA_SIZE_SEL_MAX) | |
126 | selected_size = max(size_bytes, cma_early_percent_memory()); | |
127 | #endif | |
128 | } | |
129 | ||
130 | if (selected_size) { | |
131 | pr_debug("%s: reserving %ld MiB for global area\n", __func__, | |
132 | selected_size / SZ_1M); | |
133 | ||
134 | dma_declare_contiguous(NULL, selected_size, 0, limit); | |
135 | } | |
136 | }; | |
137 | ||
138 | static DEFINE_MUTEX(cma_mutex); | |
139 | ||
140 | static __init int cma_activate_area(unsigned long base_pfn, unsigned long count) | |
141 | { | |
142 | unsigned long pfn = base_pfn; | |
143 | unsigned i = count >> pageblock_order; | |
144 | struct zone *zone; | |
145 | ||
146 | WARN_ON_ONCE(!pfn_valid(pfn)); | |
147 | zone = page_zone(pfn_to_page(pfn)); | |
148 | ||
149 | do { | |
150 | unsigned j; | |
151 | base_pfn = pfn; | |
152 | for (j = pageblock_nr_pages; j; --j, pfn++) { | |
153 | WARN_ON_ONCE(!pfn_valid(pfn)); | |
154 | if (page_zone(pfn_to_page(pfn)) != zone) | |
155 | return -EINVAL; | |
156 | } | |
157 | init_cma_reserved_pageblock(pfn_to_page(base_pfn)); | |
158 | } while (--i); | |
159 | return 0; | |
160 | } | |
161 | ||
162 | static __init struct cma *cma_create_area(unsigned long base_pfn, | |
163 | unsigned long count) | |
164 | { | |
165 | int bitmap_size = BITS_TO_LONGS(count) * sizeof(long); | |
166 | struct cma *cma; | |
167 | int ret = -ENOMEM; | |
168 | ||
169 | pr_debug("%s(base %08lx, count %lx)\n", __func__, base_pfn, count); | |
170 | ||
171 | cma = kmalloc(sizeof *cma, GFP_KERNEL); | |
172 | if (!cma) | |
173 | return ERR_PTR(-ENOMEM); | |
174 | ||
175 | cma->base_pfn = base_pfn; | |
176 | cma->count = count; | |
177 | cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL); | |
178 | ||
179 | if (!cma->bitmap) | |
180 | goto no_mem; | |
181 | ||
182 | ret = cma_activate_area(base_pfn, count); | |
183 | if (ret) | |
184 | goto error; | |
185 | ||
186 | pr_debug("%s: returned %p\n", __func__, (void *)cma); | |
187 | return cma; | |
188 | ||
189 | error: | |
190 | kfree(cma->bitmap); | |
191 | no_mem: | |
192 | kfree(cma); | |
193 | return ERR_PTR(ret); | |
194 | } | |
195 | ||
196 | static struct cma_reserved { | |
197 | phys_addr_t start; | |
198 | unsigned long size; | |
199 | struct device *dev; | |
200 | } cma_reserved[MAX_CMA_AREAS] __initdata; | |
201 | static unsigned cma_reserved_count __initdata; | |
202 | ||
203 | static int __init cma_init_reserved_areas(void) | |
204 | { | |
205 | struct cma_reserved *r = cma_reserved; | |
206 | unsigned i = cma_reserved_count; | |
207 | ||
208 | pr_debug("%s()\n", __func__); | |
209 | ||
210 | for (; i; --i, ++r) { | |
211 | struct cma *cma; | |
212 | cma = cma_create_area(PFN_DOWN(r->start), | |
213 | r->size >> PAGE_SHIFT); | |
214 | if (!IS_ERR(cma)) | |
215 | dev_set_cma_area(r->dev, cma); | |
216 | } | |
217 | return 0; | |
218 | } | |
219 | core_initcall(cma_init_reserved_areas); | |
220 | ||
221 | /** | |
222 | * dma_declare_contiguous() - reserve area for contiguous memory handling | |
223 | * for particular device | |
224 | * @dev: Pointer to device structure. | |
225 | * @size: Size of the reserved memory. | |
226 | * @base: Start address of the reserved memory (optional, 0 for any). | |
227 | * @limit: End address of the reserved memory (optional, 0 for any). | |
228 | * | |
229 | * This function reserves memory for specified device. It should be | |
230 | * called by board specific code when early allocator (memblock or bootmem) | |
231 | * is still activate. | |
232 | */ | |
233 | int __init dma_declare_contiguous(struct device *dev, unsigned long size, | |
234 | phys_addr_t base, phys_addr_t limit) | |
235 | { | |
236 | struct cma_reserved *r = &cma_reserved[cma_reserved_count]; | |
237 | unsigned long alignment; | |
238 | ||
239 | pr_debug("%s(size %lx, base %08lx, limit %08lx)\n", __func__, | |
240 | (unsigned long)size, (unsigned long)base, | |
241 | (unsigned long)limit); | |
242 | ||
243 | /* Sanity checks */ | |
244 | if (cma_reserved_count == ARRAY_SIZE(cma_reserved)) { | |
245 | pr_err("Not enough slots for CMA reserved regions!\n"); | |
246 | return -ENOSPC; | |
247 | } | |
248 | ||
249 | if (!size) | |
250 | return -EINVAL; | |
251 | ||
252 | /* Sanitise input arguments */ | |
253 | alignment = PAGE_SIZE << max(MAX_ORDER, pageblock_order); | |
254 | base = ALIGN(base, alignment); | |
255 | size = ALIGN(size, alignment); | |
256 | limit &= ~(alignment - 1); | |
257 | ||
258 | /* Reserve memory */ | |
259 | if (base) { | |
260 | if (memblock_is_region_reserved(base, size) || | |
261 | memblock_reserve(base, size) < 0) { | |
262 | base = -EBUSY; | |
263 | goto err; | |
264 | } | |
265 | } else { | |
266 | /* | |
267 | * Use __memblock_alloc_base() since | |
268 | * memblock_alloc_base() panic()s. | |
269 | */ | |
270 | phys_addr_t addr = __memblock_alloc_base(size, alignment, limit); | |
271 | if (!addr) { | |
272 | base = -ENOMEM; | |
273 | goto err; | |
274 | } else if (addr + size > ~(unsigned long)0) { | |
275 | memblock_free(addr, size); | |
276 | base = -EINVAL; | |
277 | goto err; | |
278 | } else { | |
279 | base = addr; | |
280 | } | |
281 | } | |
282 | ||
283 | /* | |
284 | * Each reserved area must be initialised later, when more kernel | |
285 | * subsystems (like slab allocator) are available. | |
286 | */ | |
287 | r->start = base; | |
288 | r->size = size; | |
289 | r->dev = dev; | |
290 | cma_reserved_count++; | |
291 | pr_info("CMA: reserved %ld MiB at %08lx\n", size / SZ_1M, | |
292 | (unsigned long)base); | |
293 | ||
294 | /* Architecture specific contiguous memory fixup. */ | |
295 | dma_contiguous_early_fixup(base, size); | |
296 | return 0; | |
297 | err: | |
298 | pr_err("CMA: failed to reserve %ld MiB\n", size / SZ_1M); | |
299 | return base; | |
300 | } | |
301 | ||
302 | /** | |
303 | * dma_alloc_from_contiguous() - allocate pages from contiguous area | |
304 | * @dev: Pointer to device for which the allocation is performed. | |
305 | * @count: Requested number of pages. | |
306 | * @align: Requested alignment of pages (in PAGE_SIZE order). | |
307 | * | |
308 | * This function allocates memory buffer for specified device. It uses | |
309 | * device specific contiguous memory area if available or the default | |
310 | * global one. Requires architecture specific get_dev_cma_area() helper | |
311 | * function. | |
312 | */ | |
313 | struct page *dma_alloc_from_contiguous(struct device *dev, int count, | |
314 | unsigned int align) | |
315 | { | |
316 | unsigned long mask, pfn, pageno, start = 0; | |
317 | struct cma *cma = dev_get_cma_area(dev); | |
318 | int ret; | |
319 | ||
320 | if (!cma || !cma->count) | |
321 | return NULL; | |
322 | ||
323 | if (align > CONFIG_CMA_ALIGNMENT) | |
324 | align = CONFIG_CMA_ALIGNMENT; | |
325 | ||
326 | pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma, | |
327 | count, align); | |
328 | ||
329 | if (!count) | |
330 | return NULL; | |
331 | ||
332 | mask = (1 << align) - 1; | |
333 | ||
334 | mutex_lock(&cma_mutex); | |
335 | ||
336 | for (;;) { | |
337 | pageno = bitmap_find_next_zero_area(cma->bitmap, cma->count, | |
338 | start, count, mask); | |
339 | if (pageno >= cma->count) { | |
340 | ret = -ENOMEM; | |
341 | goto error; | |
342 | } | |
343 | ||
344 | pfn = cma->base_pfn + pageno; | |
345 | ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA); | |
346 | if (ret == 0) { | |
347 | bitmap_set(cma->bitmap, pageno, count); | |
348 | break; | |
349 | } else if (ret != -EBUSY) { | |
350 | goto error; | |
351 | } | |
352 | pr_debug("%s(): memory range at %p is busy, retrying\n", | |
353 | __func__, pfn_to_page(pfn)); | |
354 | /* try again with a bit different memory target */ | |
355 | start = pageno + mask + 1; | |
356 | } | |
357 | ||
358 | mutex_unlock(&cma_mutex); | |
359 | ||
360 | pr_debug("%s(): returned %p\n", __func__, pfn_to_page(pfn)); | |
361 | return pfn_to_page(pfn); | |
362 | error: | |
363 | mutex_unlock(&cma_mutex); | |
364 | return NULL; | |
365 | } | |
366 | ||
367 | /** | |
368 | * dma_release_from_contiguous() - release allocated pages | |
369 | * @dev: Pointer to device for which the pages were allocated. | |
370 | * @pages: Allocated pages. | |
371 | * @count: Number of allocated pages. | |
372 | * | |
373 | * This function releases memory allocated by dma_alloc_from_contiguous(). | |
374 | * It returns false when provided pages do not belong to contiguous area and | |
375 | * true otherwise. | |
376 | */ | |
377 | bool dma_release_from_contiguous(struct device *dev, struct page *pages, | |
378 | int count) | |
379 | { | |
380 | struct cma *cma = dev_get_cma_area(dev); | |
381 | unsigned long pfn; | |
382 | ||
383 | if (!cma || !pages) | |
384 | return false; | |
385 | ||
386 | pr_debug("%s(page %p)\n", __func__, (void *)pages); | |
387 | ||
388 | pfn = page_to_pfn(pages); | |
389 | ||
390 | if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count) | |
391 | return false; | |
392 | ||
393 | VM_BUG_ON(pfn + count > cma->base_pfn + cma->count); | |
394 | ||
395 | mutex_lock(&cma_mutex); | |
396 | bitmap_clear(cma->bitmap, pfn - cma->base_pfn, count); | |
397 | free_contig_range(pfn, count); | |
398 | mutex_unlock(&cma_mutex); | |
399 | ||
400 | return true; | |
401 | } |