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