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 EXPORT_SYMBOL_GPL(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 #ifdef CONFIG_DMA_NUMA_CMA
95
96 static struct cma *dma_contiguous_numa_area[MAX_NUMNODES];
97 static phys_addr_t numa_cma_size[MAX_NUMNODES] __initdata;
98 static struct cma *dma_contiguous_pernuma_area[MAX_NUMNODES];
99 static phys_addr_t pernuma_size_bytes __initdata;
100
early_numa_cma(char * p)101 static int __init early_numa_cma(char *p)
102 {
103 int nid, count = 0;
104 unsigned long tmp;
105 char *s = p;
106
107 while (*s) {
108 if (sscanf(s, "%lu%n", &tmp, &count) != 1)
109 break;
110
111 if (s[count] == ':') {
112 if (tmp >= MAX_NUMNODES)
113 break;
114 nid = array_index_nospec(tmp, MAX_NUMNODES);
115
116 s += count + 1;
117 tmp = memparse(s, &s);
118 numa_cma_size[nid] = tmp;
119
120 if (*s == ',')
121 s++;
122 else
123 break;
124 } else
125 break;
126 }
127
128 return 0;
129 }
130 early_param("numa_cma", early_numa_cma);
131
early_cma_pernuma(char * p)132 static int __init early_cma_pernuma(char *p)
133 {
134 pernuma_size_bytes = memparse(p, &p);
135 return 0;
136 }
137 early_param("cma_pernuma", early_cma_pernuma);
138 #endif
139
140 #ifdef CONFIG_CMA_SIZE_PERCENTAGE
141
cma_early_percent_memory(void)142 static phys_addr_t __init __maybe_unused cma_early_percent_memory(void)
143 {
144 unsigned long total_pages = PHYS_PFN(memblock_phys_mem_size());
145
146 return (total_pages * CONFIG_CMA_SIZE_PERCENTAGE / 100) << PAGE_SHIFT;
147 }
148
149 #else
150
cma_early_percent_memory(void)151 static inline __maybe_unused phys_addr_t cma_early_percent_memory(void)
152 {
153 return 0;
154 }
155
156 #endif
157
158 #ifdef CONFIG_DMA_NUMA_CMA
dma_numa_cma_reserve(void)159 static void __init dma_numa_cma_reserve(void)
160 {
161 int nid;
162
163 for_each_node(nid) {
164 int ret;
165 char name[CMA_MAX_NAME];
166 struct cma **cma;
167
168 if (!node_online(nid)) {
169 if (pernuma_size_bytes || numa_cma_size[nid])
170 pr_warn("invalid node %d specified\n", nid);
171 continue;
172 }
173
174 if (pernuma_size_bytes) {
175
176 cma = &dma_contiguous_pernuma_area[nid];
177 snprintf(name, sizeof(name), "pernuma%d", nid);
178 ret = cma_declare_contiguous_nid(0, pernuma_size_bytes, 0, 0,
179 0, false, name, cma, nid);
180 if (ret)
181 pr_warn("%s: reservation failed: err %d, node %d", __func__,
182 ret, nid);
183 }
184
185 if (numa_cma_size[nid]) {
186
187 cma = &dma_contiguous_numa_area[nid];
188 snprintf(name, sizeof(name), "numa%d", nid);
189 ret = cma_declare_contiguous_nid(0, numa_cma_size[nid], 0, 0, 0, false,
190 name, cma, nid);
191 if (ret)
192 pr_warn("%s: reservation failed: err %d, node %d", __func__,
193 ret, nid);
194 }
195 }
196 }
197 #else
dma_numa_cma_reserve(void)198 static inline void __init dma_numa_cma_reserve(void)
199 {
200 }
201 #endif
202
203 /**
204 * dma_contiguous_reserve() - reserve area(s) for contiguous memory handling
205 * @limit: End address of the reserved memory (optional, 0 for any).
206 *
207 * This function reserves memory from early allocator. It should be
208 * called by arch specific code once the early allocator (memblock or bootmem)
209 * has been activated and all other subsystems have already allocated/reserved
210 * memory.
211 */
dma_contiguous_reserve(phys_addr_t limit)212 void __init dma_contiguous_reserve(phys_addr_t limit)
213 {
214 phys_addr_t selected_size = 0;
215 phys_addr_t selected_base = 0;
216 phys_addr_t selected_limit = limit;
217 bool fixed = false;
218
219 dma_numa_cma_reserve();
220
221 pr_debug("%s(limit %08lx)\n", __func__, (unsigned long)limit);
222
223 if (size_cmdline != -1) {
224 selected_size = size_cmdline;
225 selected_base = base_cmdline;
226 selected_limit = min_not_zero(limit_cmdline, limit);
227 if (base_cmdline + size_cmdline == limit_cmdline)
228 fixed = true;
229 } else {
230 #ifdef CONFIG_CMA_SIZE_SEL_MBYTES
231 selected_size = size_bytes;
232 #elif defined(CONFIG_CMA_SIZE_SEL_PERCENTAGE)
233 selected_size = cma_early_percent_memory();
234 #elif defined(CONFIG_CMA_SIZE_SEL_MIN)
235 selected_size = min(size_bytes, cma_early_percent_memory());
236 #elif defined(CONFIG_CMA_SIZE_SEL_MAX)
237 selected_size = max(size_bytes, cma_early_percent_memory());
238 #endif
239 }
240
241 if (selected_size && !dma_contiguous_default_area) {
242 pr_debug("%s: reserving %ld MiB for global area\n", __func__,
243 (unsigned long)selected_size / SZ_1M);
244
245 dma_contiguous_reserve_area(selected_size, selected_base,
246 selected_limit,
247 &dma_contiguous_default_area,
248 fixed);
249 }
250 }
251
252 void __weak
dma_contiguous_early_fixup(phys_addr_t base,unsigned long size)253 dma_contiguous_early_fixup(phys_addr_t base, unsigned long size)
254 {
255 }
256
257 /**
258 * dma_contiguous_reserve_area() - reserve custom contiguous area
259 * @size: Size of the reserved area (in bytes),
260 * @base: Base address of the reserved area optional, use 0 for any
261 * @limit: End address of the reserved memory (optional, 0 for any).
262 * @res_cma: Pointer to store the created cma region.
263 * @fixed: hint about where to place the reserved area
264 *
265 * This function reserves memory from early allocator. It should be
266 * called by arch specific code once the early allocator (memblock or bootmem)
267 * has been activated and all other subsystems have already allocated/reserved
268 * memory. This function allows to create custom reserved areas for specific
269 * devices.
270 *
271 * If @fixed is true, reserve contiguous area at exactly @base. If false,
272 * reserve in range from @base to @limit.
273 */
dma_contiguous_reserve_area(phys_addr_t size,phys_addr_t base,phys_addr_t limit,struct cma ** res_cma,bool fixed)274 int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
275 phys_addr_t limit, struct cma **res_cma,
276 bool fixed)
277 {
278 int ret;
279
280 memblock_memsize_disable_tracking();
281 ret = cma_declare_contiguous(base, size, limit, 0, 0, fixed,
282 "reserved", res_cma);
283 if (ret)
284 goto out;
285
286 /* Architecture specific contiguous memory fixup. */
287 dma_contiguous_early_fixup(cma_get_base(*res_cma),
288 cma_get_size(*res_cma));
289
290 memblock_memsize_record("dma_cma", cma_get_base(*res_cma),
291 cma_get_size(*res_cma), false, true);
292 out:
293 memblock_memsize_enable_tracking();
294 return ret;
295 }
296
297 /**
298 * dma_alloc_from_contiguous() - allocate pages from contiguous area
299 * @dev: Pointer to device for which the allocation is performed.
300 * @count: Requested number of pages.
301 * @align: Requested alignment of pages (in PAGE_SIZE order).
302 * @no_warn: Avoid printing message about failed allocation.
303 *
304 * This function allocates memory buffer for specified device. It uses
305 * device specific contiguous memory area if available or the default
306 * global one. Requires architecture specific dev_get_cma_area() helper
307 * function.
308 */
dma_alloc_from_contiguous(struct device * dev,size_t count,unsigned int align,bool no_warn)309 struct page *dma_alloc_from_contiguous(struct device *dev, size_t count,
310 unsigned int align, bool no_warn)
311 {
312 if (align > CONFIG_CMA_ALIGNMENT)
313 align = CONFIG_CMA_ALIGNMENT;
314
315 return cma_alloc(dev_get_cma_area(dev), count, align, no_warn);
316 }
317
318 /**
319 * dma_release_from_contiguous() - release allocated pages
320 * @dev: Pointer to device for which the pages were allocated.
321 * @pages: Allocated pages.
322 * @count: Number of allocated pages.
323 *
324 * This function releases memory allocated by dma_alloc_from_contiguous().
325 * It returns false when provided pages do not belong to contiguous area and
326 * true otherwise.
327 */
dma_release_from_contiguous(struct device * dev,struct page * pages,int count)328 bool dma_release_from_contiguous(struct device *dev, struct page *pages,
329 int count)
330 {
331 return cma_release(dev_get_cma_area(dev), pages, count);
332 }
333
cma_alloc_aligned(struct cma * cma,size_t size,gfp_t gfp)334 static struct page *cma_alloc_aligned(struct cma *cma, size_t size, gfp_t gfp)
335 {
336 unsigned int align = min(get_order(size), CONFIG_CMA_ALIGNMENT);
337
338 return cma_alloc(cma, size >> PAGE_SHIFT, align, gfp & __GFP_NOWARN);
339 }
340
341 /**
342 * dma_alloc_contiguous() - allocate contiguous pages
343 * @dev: Pointer to device for which the allocation is performed.
344 * @size: Requested allocation size.
345 * @gfp: Allocation flags.
346 *
347 * tries to use device specific contiguous memory area if available, or it
348 * tries to use per-numa cma, if the allocation fails, it will fallback to
349 * try default global one.
350 *
351 * Note that it bypass one-page size of allocations from the per-numa and
352 * global area as the addresses within one page are always contiguous, so
353 * there is no need to waste CMA pages for that kind; it also helps reduce
354 * fragmentations.
355 */
dma_alloc_contiguous(struct device * dev,size_t size,gfp_t gfp)356 struct page *dma_alloc_contiguous(struct device *dev, size_t size, gfp_t gfp)
357 {
358 #ifdef CONFIG_DMA_NUMA_CMA
359 int nid = dev_to_node(dev);
360 #endif
361
362 /* CMA can be used only in the context which permits sleeping */
363 if (!gfpflags_allow_blocking(gfp))
364 return NULL;
365 if (dev->cma_area)
366 return cma_alloc_aligned(dev->cma_area, size, gfp);
367 if (size <= PAGE_SIZE)
368 return NULL;
369
370 #ifdef CONFIG_DMA_NUMA_CMA
371 if (nid != NUMA_NO_NODE && !(gfp & (GFP_DMA | GFP_DMA32))) {
372 struct cma *cma = dma_contiguous_pernuma_area[nid];
373 struct page *page;
374
375 if (cma) {
376 page = cma_alloc_aligned(cma, size, gfp);
377 if (page)
378 return page;
379 }
380
381 cma = dma_contiguous_numa_area[nid];
382 if (cma) {
383 page = cma_alloc_aligned(cma, size, gfp);
384 if (page)
385 return page;
386 }
387 }
388 #endif
389 if (!dma_contiguous_default_area)
390 return NULL;
391
392 return cma_alloc_aligned(dma_contiguous_default_area, size, gfp);
393 }
394
395 /**
396 * dma_free_contiguous() - release allocated pages
397 * @dev: Pointer to device for which the pages were allocated.
398 * @page: Pointer to the allocated pages.
399 * @size: Size of allocated pages.
400 *
401 * This function releases memory allocated by dma_alloc_contiguous(). As the
402 * cma_release returns false when provided pages do not belong to contiguous
403 * area and true otherwise, this function then does a fallback __free_pages()
404 * upon a false-return.
405 */
dma_free_contiguous(struct device * dev,struct page * page,size_t size)406 void dma_free_contiguous(struct device *dev, struct page *page, size_t size)
407 {
408 unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
409
410 /* if dev has its own cma, free page from there */
411 if (dev->cma_area) {
412 if (cma_release(dev->cma_area, page, count))
413 return;
414 } else {
415 /*
416 * otherwise, page is from either per-numa cma or default cma
417 */
418 #ifdef CONFIG_DMA_NUMA_CMA
419 if (cma_release(dma_contiguous_pernuma_area[page_to_nid(page)],
420 page, count))
421 return;
422 if (cma_release(dma_contiguous_numa_area[page_to_nid(page)],
423 page, count))
424 return;
425 #endif
426 if (cma_release(dma_contiguous_default_area, page, count))
427 return;
428 }
429
430 /* not in any cma, free from buddy */
431 __free_pages(page, get_order(size));
432 }
433
434 /*
435 * Support for reserved memory regions defined in device tree
436 */
437 #ifdef CONFIG_OF_RESERVED_MEM
438 #include <linux/of.h>
439 #include <linux/of_fdt.h>
440 #include <linux/of_reserved_mem.h>
441
442 #undef pr_fmt
443 #define pr_fmt(fmt) fmt
444
rmem_cma_device_init(struct reserved_mem * rmem,struct device * dev)445 static int rmem_cma_device_init(struct reserved_mem *rmem, struct device *dev)
446 {
447 dev->cma_area = rmem->priv;
448 return 0;
449 }
450
rmem_cma_device_release(struct reserved_mem * rmem,struct device * dev)451 static void rmem_cma_device_release(struct reserved_mem *rmem,
452 struct device *dev)
453 {
454 dev->cma_area = NULL;
455 }
456
457 static const struct reserved_mem_ops rmem_cma_ops = {
458 .device_init = rmem_cma_device_init,
459 .device_release = rmem_cma_device_release,
460 };
461
rmem_cma_setup(struct reserved_mem * rmem)462 static int __init rmem_cma_setup(struct reserved_mem *rmem)
463 {
464 unsigned long node = rmem->fdt_node;
465 bool default_cma = of_get_flat_dt_prop(node, "linux,cma-default", NULL);
466 struct cma *cma;
467 bool gcma;
468 int err;
469
470 if (size_cmdline != -1 && default_cma) {
471 pr_info("Reserved memory: bypass %s node, using cmdline CMA params instead\n",
472 rmem->name);
473 return -EBUSY;
474 }
475
476 if (!of_get_flat_dt_prop(node, "reusable", NULL) ||
477 of_get_flat_dt_prop(node, "no-map", NULL))
478 return -EINVAL;
479
480 if (!IS_ALIGNED(rmem->base | rmem->size, CMA_MIN_ALIGNMENT_BYTES)) {
481 pr_err("Reserved memory: incorrect alignment of CMA region\n");
482 return -EINVAL;
483 }
484
485 gcma = !!of_get_flat_dt_prop(node, "guarantee", NULL);
486 #ifndef CONFIG_GCMA
487 if (gcma) {
488 pr_err("Reserved memory: unable to setup GCMA region, GCMA is not enabled\n");
489 return -EINVAL;
490 }
491 #endif
492 err = cma_init_reserved_mem(rmem->base, rmem->size, 0, rmem->name,
493 &cma, gcma);
494 if (err) {
495 pr_err("Reserved memory: unable to setup CMA region\n");
496 return err;
497 }
498
499 if (default_cma)
500 dma_contiguous_default_area = cma;
501
502 rmem->ops = &rmem_cma_ops;
503 rmem->priv = cma;
504
505 pr_info("Reserved memory: created CMA memory pool at %pa, size %ld MiB\n",
506 &rmem->base, (unsigned long)rmem->size / SZ_1M);
507
508 return 0;
509 }
510 RESERVEDMEM_OF_DECLARE(cma, "shared-dma-pool", rmem_cma_setup);
511 #endif
512