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