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