1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Contiguous Memory Allocator for DMA mapping framework
4 * Copyright (c) 2010-2011 by Samsung Electronics.
5 * Written by:
6 * Marek Szyprowski <m.szyprowski@samsung.com>
7 * Michal Nazarewicz <mina86@mina86.com>
8 *
9 * Contiguous Memory Allocator
10 *
11 * The Contiguous Memory Allocator (CMA) makes it possible to
12 * allocate big contiguous chunks of memory after the system has
13 * booted.
14 *
15 * Why is it needed?
16 *
17 * Various devices on embedded systems have no scatter-getter and/or
18 * IO map support and require contiguous blocks of memory to
19 * operate. They include devices such as cameras, hardware video
20 * coders, etc.
21 *
22 * Such devices often require big memory buffers (a full HD frame
23 * is, for instance, more than 2 mega pixels large, i.e. more than 6
24 * MB of memory), which makes mechanisms such as kmalloc() or
25 * alloc_page() ineffective.
26 *
27 * At the same time, a solution where a big memory region is
28 * reserved for a device is suboptimal since often more memory is
29 * reserved then strictly required and, moreover, the memory is
30 * inaccessible to page system even if device drivers don't use it.
31 *
32 * CMA tries to solve this issue by operating on memory regions
33 * where only movable pages can be allocated from. This way, kernel
34 * can use the memory for pagecache and when device driver requests
35 * it, allocated pages can be migrated.
36 */
37
38 #define pr_fmt(fmt) "cma: " fmt
39
40 #include <asm/page.h>
41
42 #include <linux/memblock.h>
43 #include <linux/err.h>
44 #include <linux/sizes.h>
45 #include <linux/dma-buf/heaps/cma.h>
46 #include <linux/dma-map-ops.h>
47 #include <linux/cma.h>
48 #include <linux/nospec.h>
49
50 #ifdef CONFIG_CMA_SIZE_MBYTES
51 #define CMA_SIZE_MBYTES CONFIG_CMA_SIZE_MBYTES
52 #else
53 #define CMA_SIZE_MBYTES 0
54 #endif
55
56 struct cma *dma_contiguous_default_area;
57
58 /*
59 * Default global CMA area size can be defined in kernel's .config.
60 * This is useful mainly for distro maintainers to create a kernel
61 * that works correctly for most supported systems.
62 * The size can be set in bytes or as a percentage of the total memory
63 * in the system.
64 *
65 * Users, who want to set the size of global CMA area for their system
66 * should use cma= kernel parameter.
67 */
68 #define size_bytes ((phys_addr_t)CMA_SIZE_MBYTES * SZ_1M)
69 static phys_addr_t size_cmdline __initdata = -1;
70 static phys_addr_t base_cmdline __initdata;
71 static phys_addr_t limit_cmdline __initdata;
72
early_cma(char * p)73 static int __init early_cma(char *p)
74 {
75 if (!p) {
76 pr_err("Config string not provided\n");
77 return -EINVAL;
78 }
79
80 size_cmdline = memparse(p, &p);
81 if (*p != '@')
82 return 0;
83 base_cmdline = memparse(p + 1, &p);
84 if (*p != '-') {
85 limit_cmdline = base_cmdline + size_cmdline;
86 return 0;
87 }
88 limit_cmdline = memparse(p + 1, &p);
89
90 return 0;
91 }
92 early_param("cma", early_cma);
93
94 /*
95 * cma_skip_dt_default_reserved_mem - This is called from the
96 * reserved_mem framework to detect if the default cma region is being
97 * set by the "cma=" kernel parameter.
98 */
cma_skip_dt_default_reserved_mem(void)99 bool __init cma_skip_dt_default_reserved_mem(void)
100 {
101 return size_cmdline != -1;
102 }
103
104 #ifdef CONFIG_DMA_NUMA_CMA
105
106 static struct cma *dma_contiguous_numa_area[MAX_NUMNODES];
107 static phys_addr_t numa_cma_size[MAX_NUMNODES] __initdata;
108 static struct cma *dma_contiguous_pernuma_area[MAX_NUMNODES];
109 static phys_addr_t pernuma_size_bytes __initdata;
110
early_numa_cma(char * p)111 static int __init early_numa_cma(char *p)
112 {
113 int nid, count = 0;
114 unsigned long tmp;
115 char *s = p;
116
117 while (*s) {
118 if (sscanf(s, "%lu%n", &tmp, &count) != 1)
119 break;
120
121 if (s[count] == ':') {
122 if (tmp >= MAX_NUMNODES)
123 break;
124 nid = array_index_nospec(tmp, MAX_NUMNODES);
125
126 s += count + 1;
127 tmp = memparse(s, &s);
128 numa_cma_size[nid] = tmp;
129
130 if (*s == ',')
131 s++;
132 else
133 break;
134 } else
135 break;
136 }
137
138 return 0;
139 }
140 early_param("numa_cma", early_numa_cma);
141
early_cma_pernuma(char * p)142 static int __init early_cma_pernuma(char *p)
143 {
144 pernuma_size_bytes = memparse(p, &p);
145 return 0;
146 }
147 early_param("cma_pernuma", early_cma_pernuma);
148 #endif
149
150 #ifdef CONFIG_CMA_SIZE_PERCENTAGE
151
cma_early_percent_memory(void)152 static phys_addr_t __init __maybe_unused cma_early_percent_memory(void)
153 {
154 unsigned long total_pages = PHYS_PFN(memblock_phys_mem_size());
155
156 return (total_pages * CONFIG_CMA_SIZE_PERCENTAGE / 100) << PAGE_SHIFT;
157 }
158
159 #else
160
cma_early_percent_memory(void)161 static inline __maybe_unused phys_addr_t cma_early_percent_memory(void)
162 {
163 return 0;
164 }
165
166 #endif
167
168 #ifdef CONFIG_DMA_NUMA_CMA
dma_numa_cma_reserve(void)169 static void __init dma_numa_cma_reserve(void)
170 {
171 int nid;
172
173 for_each_node(nid) {
174 int ret;
175 char name[CMA_MAX_NAME];
176 struct cma **cma;
177
178 if (!node_online(nid)) {
179 if (pernuma_size_bytes || numa_cma_size[nid])
180 pr_warn("invalid node %d specified\n", nid);
181 continue;
182 }
183
184 if (pernuma_size_bytes) {
185
186 cma = &dma_contiguous_pernuma_area[nid];
187 snprintf(name, sizeof(name), "pernuma%d", nid);
188 ret = cma_declare_contiguous_nid(0, pernuma_size_bytes, 0, 0,
189 0, false, name, cma, nid);
190 if (ret)
191 pr_warn("%s: reservation failed: err %d, node %d", __func__,
192 ret, nid);
193 }
194
195 if (numa_cma_size[nid]) {
196
197 cma = &dma_contiguous_numa_area[nid];
198 snprintf(name, sizeof(name), "numa%d", nid);
199 ret = cma_declare_contiguous_nid(0, numa_cma_size[nid], 0, 0, 0, false,
200 name, cma, nid);
201 if (ret)
202 pr_warn("%s: reservation failed: err %d, node %d", __func__,
203 ret, nid);
204 }
205 }
206 }
207 #else
dma_numa_cma_reserve(void)208 static inline void __init dma_numa_cma_reserve(void)
209 {
210 }
211 #endif
212
213 /**
214 * dma_contiguous_reserve() - reserve area(s) for contiguous memory handling
215 * @limit: End address of the reserved memory (optional, 0 for any).
216 *
217 * This function reserves memory from early allocator. It should be
218 * called by arch specific code once the early allocator (memblock or bootmem)
219 * has been activated and all other subsystems have already allocated/reserved
220 * memory.
221 */
dma_contiguous_reserve(phys_addr_t limit)222 void __init dma_contiguous_reserve(phys_addr_t limit)
223 {
224 phys_addr_t selected_size = 0;
225 phys_addr_t selected_base = 0;
226 phys_addr_t selected_limit = limit;
227 bool fixed = false;
228
229 dma_numa_cma_reserve();
230
231 pr_debug("%s(limit %08lx)\n", __func__, (unsigned long)limit);
232
233 if (size_cmdline != -1) {
234 selected_size = size_cmdline;
235 selected_base = base_cmdline;
236
237 /* Hornor the user setup dma address limit */
238 selected_limit = limit_cmdline ?: limit;
239
240 if (base_cmdline + size_cmdline == limit_cmdline)
241 fixed = true;
242 } else {
243 #ifdef CONFIG_CMA_SIZE_SEL_MBYTES
244 selected_size = size_bytes;
245 #elif defined(CONFIG_CMA_SIZE_SEL_PERCENTAGE)
246 selected_size = cma_early_percent_memory();
247 #elif defined(CONFIG_CMA_SIZE_SEL_MIN)
248 selected_size = min(size_bytes, cma_early_percent_memory());
249 #elif defined(CONFIG_CMA_SIZE_SEL_MAX)
250 selected_size = max(size_bytes, cma_early_percent_memory());
251 #endif
252 }
253
254 if (selected_size && !dma_contiguous_default_area) {
255 int ret;
256
257 pr_debug("%s: reserving %ld MiB for global area\n", __func__,
258 (unsigned long)selected_size / SZ_1M);
259
260 dma_contiguous_reserve_area(selected_size, selected_base,
261 selected_limit,
262 &dma_contiguous_default_area,
263 fixed);
264
265 ret = dma_heap_cma_register_heap(dma_contiguous_default_area);
266 if (ret)
267 pr_warn("Couldn't register default CMA heap.");
268 }
269 }
270
271 void __weak
dma_contiguous_early_fixup(phys_addr_t base,unsigned long size)272 dma_contiguous_early_fixup(phys_addr_t base, unsigned long size)
273 {
274 }
275
276 /**
277 * dma_contiguous_reserve_area() - reserve custom contiguous area
278 * @size: Size of the reserved area (in bytes),
279 * @base: Base address of the reserved area optional, use 0 for any
280 * @limit: End address of the reserved memory (optional, 0 for any).
281 * @res_cma: Pointer to store the created cma region.
282 * @fixed: hint about where to place the reserved area
283 *
284 * This function reserves memory from early allocator. It should be
285 * called by arch specific code once the early allocator (memblock or bootmem)
286 * has been activated and all other subsystems have already allocated/reserved
287 * memory. This function allows to create custom reserved areas for specific
288 * devices.
289 *
290 * If @fixed is true, reserve contiguous area at exactly @base. If false,
291 * reserve in range from @base to @limit.
292 */
dma_contiguous_reserve_area(phys_addr_t size,phys_addr_t base,phys_addr_t limit,struct cma ** res_cma,bool fixed)293 int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
294 phys_addr_t limit, struct cma **res_cma,
295 bool fixed)
296 {
297 int ret;
298
299 ret = cma_declare_contiguous(base, size, limit, 0, 0, fixed,
300 "reserved", res_cma);
301 if (ret)
302 return ret;
303
304 /* Architecture specific contiguous memory fixup. */
305 dma_contiguous_early_fixup(cma_get_base(*res_cma),
306 cma_get_size(*res_cma));
307
308 return 0;
309 }
310
311 /**
312 * dma_alloc_from_contiguous() - allocate pages from contiguous area
313 * @dev: Pointer to device for which the allocation is performed.
314 * @count: Requested number of pages.
315 * @align: Requested alignment of pages (in PAGE_SIZE order).
316 * @no_warn: Avoid printing message about failed allocation.
317 *
318 * This function allocates memory buffer for specified device. It uses
319 * device specific contiguous memory area if available or the default
320 * global one. Requires architecture specific dev_get_cma_area() helper
321 * function.
322 */
dma_alloc_from_contiguous(struct device * dev,size_t count,unsigned int align,bool no_warn)323 struct page *dma_alloc_from_contiguous(struct device *dev, size_t count,
324 unsigned int align, bool no_warn)
325 {
326 if (align > CONFIG_CMA_ALIGNMENT)
327 align = CONFIG_CMA_ALIGNMENT;
328
329 return cma_alloc(dev_get_cma_area(dev), count, align, no_warn);
330 }
331
332 /**
333 * dma_release_from_contiguous() - release allocated pages
334 * @dev: Pointer to device for which the pages were allocated.
335 * @pages: Allocated pages.
336 * @count: Number of allocated pages.
337 *
338 * This function releases memory allocated by dma_alloc_from_contiguous().
339 * It returns false when provided pages do not belong to contiguous area and
340 * true otherwise.
341 */
dma_release_from_contiguous(struct device * dev,struct page * pages,int count)342 bool dma_release_from_contiguous(struct device *dev, struct page *pages,
343 int count)
344 {
345 return cma_release(dev_get_cma_area(dev), pages, count);
346 }
347
cma_alloc_aligned(struct cma * cma,size_t size,gfp_t gfp)348 static struct page *cma_alloc_aligned(struct cma *cma, size_t size, gfp_t gfp)
349 {
350 unsigned int align = min(get_order(size), CONFIG_CMA_ALIGNMENT);
351
352 return cma_alloc(cma, size >> PAGE_SHIFT, align, gfp & __GFP_NOWARN);
353 }
354
355 /**
356 * dma_alloc_contiguous() - allocate contiguous pages
357 * @dev: Pointer to device for which the allocation is performed.
358 * @size: Requested allocation size.
359 * @gfp: Allocation flags.
360 *
361 * tries to use device specific contiguous memory area if available, or it
362 * tries to use per-numa cma, if the allocation fails, it will fallback to
363 * try default global one.
364 *
365 * Note that it bypass one-page size of allocations from the per-numa and
366 * global area as the addresses within one page are always contiguous, so
367 * there is no need to waste CMA pages for that kind; it also helps reduce
368 * fragmentations.
369 */
dma_alloc_contiguous(struct device * dev,size_t size,gfp_t gfp)370 struct page *dma_alloc_contiguous(struct device *dev, size_t size, gfp_t gfp)
371 {
372 #ifdef CONFIG_DMA_NUMA_CMA
373 int nid = dev_to_node(dev);
374 #endif
375
376 /* CMA can be used only in the context which permits sleeping */
377 if (!gfpflags_allow_blocking(gfp))
378 return NULL;
379 if (dev->cma_area)
380 return cma_alloc_aligned(dev->cma_area, size, gfp);
381 if (size <= PAGE_SIZE)
382 return NULL;
383
384 #ifdef CONFIG_DMA_NUMA_CMA
385 if (nid != NUMA_NO_NODE && !(gfp & (GFP_DMA | GFP_DMA32))) {
386 struct cma *cma = dma_contiguous_pernuma_area[nid];
387 struct page *page;
388
389 if (cma) {
390 page = cma_alloc_aligned(cma, size, gfp);
391 if (page)
392 return page;
393 }
394
395 cma = dma_contiguous_numa_area[nid];
396 if (cma) {
397 page = cma_alloc_aligned(cma, size, gfp);
398 if (page)
399 return page;
400 }
401 }
402 #endif
403 if (!dma_contiguous_default_area)
404 return NULL;
405
406 return cma_alloc_aligned(dma_contiguous_default_area, size, gfp);
407 }
408
409 /**
410 * dma_free_contiguous() - release allocated pages
411 * @dev: Pointer to device for which the pages were allocated.
412 * @page: Pointer to the allocated pages.
413 * @size: Size of allocated pages.
414 *
415 * This function releases memory allocated by dma_alloc_contiguous(). As the
416 * cma_release returns false when provided pages do not belong to contiguous
417 * area and true otherwise, this function then does a fallback __free_pages()
418 * upon a false-return.
419 */
dma_free_contiguous(struct device * dev,struct page * page,size_t size)420 void dma_free_contiguous(struct device *dev, struct page *page, size_t size)
421 {
422 unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
423
424 /* if dev has its own cma, free page from there */
425 if (dev->cma_area) {
426 if (cma_release(dev->cma_area, page, count))
427 return;
428 } else {
429 /*
430 * otherwise, page is from either per-numa cma or default cma
431 */
432 #ifdef CONFIG_DMA_NUMA_CMA
433 if (cma_release(dma_contiguous_pernuma_area[page_to_nid(page)],
434 page, count))
435 return;
436 if (cma_release(dma_contiguous_numa_area[page_to_nid(page)],
437 page, count))
438 return;
439 #endif
440 if (cma_release(dma_contiguous_default_area, page, count))
441 return;
442 }
443
444 /* not in any cma, free from buddy */
445 __free_pages(page, get_order(size));
446 }
447
448 /*
449 * Support for reserved memory regions defined in device tree
450 */
451 #ifdef CONFIG_OF_RESERVED_MEM
452 #include <linux/of.h>
453 #include <linux/of_fdt.h>
454 #include <linux/of_reserved_mem.h>
455
456 #undef pr_fmt
457 #define pr_fmt(fmt) fmt
458
rmem_cma_device_init(struct reserved_mem * rmem,struct device * dev)459 static int rmem_cma_device_init(struct reserved_mem *rmem, struct device *dev)
460 {
461 dev->cma_area = rmem->priv;
462 return 0;
463 }
464
rmem_cma_device_release(struct reserved_mem * rmem,struct device * dev)465 static void rmem_cma_device_release(struct reserved_mem *rmem,
466 struct device *dev)
467 {
468 dev->cma_area = NULL;
469 }
470
471 static const struct reserved_mem_ops rmem_cma_ops = {
472 .device_init = rmem_cma_device_init,
473 .device_release = rmem_cma_device_release,
474 };
475
rmem_cma_setup(struct reserved_mem * rmem)476 static int __init rmem_cma_setup(struct reserved_mem *rmem)
477 {
478 unsigned long node = rmem->fdt_node;
479 bool default_cma = of_get_flat_dt_prop(node, "linux,cma-default", NULL);
480 struct cma *cma;
481 int err;
482
483 if (!of_get_flat_dt_prop(node, "reusable", NULL) ||
484 of_get_flat_dt_prop(node, "no-map", NULL))
485 return -EINVAL;
486
487 if (!IS_ALIGNED(rmem->base | rmem->size, CMA_MIN_ALIGNMENT_BYTES)) {
488 pr_err("Reserved memory: incorrect alignment of CMA region\n");
489 return -EINVAL;
490 }
491
492 err = cma_init_reserved_mem(rmem->base, rmem->size, 0, rmem->name, &cma);
493 if (err) {
494 pr_err("Reserved memory: unable to setup CMA region\n");
495 return err;
496 }
497
498 if (default_cma)
499 dma_contiguous_default_area = cma;
500
501 rmem->ops = &rmem_cma_ops;
502 rmem->priv = cma;
503
504 pr_info("Reserved memory: created CMA memory pool at %pa, size %ld MiB\n",
505 &rmem->base, (unsigned long)rmem->size / SZ_1M);
506
507 err = dma_heap_cma_register_heap(cma);
508 if (err)
509 pr_warn("Couldn't register CMA heap.");
510
511 return 0;
512 }
513 RESERVEDMEM_OF_DECLARE(cma, "shared-dma-pool", rmem_cma_setup);
514 #endif
515