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