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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 : :
10 : : #define pr_fmt(fmt) "cma: " fmt
11 : :
12 : : #ifdef CONFIG_CMA_DEBUG
13 : : #ifndef DEBUG
14 : : # define DEBUG
15 : : #endif
16 : : #endif
17 : :
18 : : #include <asm/page.h>
19 : : #include <asm/dma-contiguous.h>
20 : :
21 : : #include <linux/memblock.h>
22 : : #include <linux/err.h>
23 : : #include <linux/sizes.h>
24 : : #include <linux/dma-contiguous.h>
25 : : #include <linux/cma.h>
26 : :
27 : : #ifdef CONFIG_CMA_SIZE_MBYTES
28 : : #define CMA_SIZE_MBYTES CONFIG_CMA_SIZE_MBYTES
29 : : #else
30 : : #define CMA_SIZE_MBYTES 0
31 : : #endif
32 : :
33 : : struct cma *dma_contiguous_default_area;
34 : :
35 : : /*
36 : : * Default global CMA area size can be defined in kernel's .config.
37 : : * This is useful mainly for distro maintainers to create a kernel
38 : : * that works correctly for most supported systems.
39 : : * The size can be set in bytes or as a percentage of the total memory
40 : : * in the system.
41 : : *
42 : : * Users, who want to set the size of global CMA area for their system
43 : : * should use cma= kernel parameter.
44 : : */
45 : : static const phys_addr_t size_bytes = (phys_addr_t)CMA_SIZE_MBYTES * SZ_1M;
46 : : static phys_addr_t size_cmdline = -1;
47 : : static phys_addr_t base_cmdline;
48 : : static phys_addr_t limit_cmdline;
49 : :
50 : 0 : static int __init early_cma(char *p)
51 : : {
52 [ # # ]: 0 : if (!p) {
53 : 0 : pr_err("Config string not provided\n");
54 : 0 : return -EINVAL;
55 : : }
56 : :
57 : 0 : size_cmdline = memparse(p, &p);
58 [ # # ]: 0 : if (*p != '@')
59 : : return 0;
60 : 0 : base_cmdline = memparse(p + 1, &p);
61 [ # # ]: 0 : if (*p != '-') {
62 : 0 : limit_cmdline = base_cmdline + size_cmdline;
63 : 0 : return 0;
64 : : }
65 : 0 : limit_cmdline = memparse(p + 1, &p);
66 : :
67 : 0 : return 0;
68 : : }
69 : : early_param("cma", early_cma);
70 : :
71 : : #ifdef CONFIG_CMA_SIZE_PERCENTAGE
72 : :
73 : : static phys_addr_t __init __maybe_unused cma_early_percent_memory(void)
74 : : {
75 : : struct memblock_region *reg;
76 : : unsigned long total_pages = 0;
77 : :
78 : : /*
79 : : * We cannot use memblock_phys_mem_size() here, because
80 : : * memblock_analyze() has not been called yet.
81 : : */
82 : : for_each_memblock(memory, reg)
83 : : total_pages += memblock_region_memory_end_pfn(reg) -
84 : : memblock_region_memory_base_pfn(reg);
85 : :
86 : : return (total_pages * CONFIG_CMA_SIZE_PERCENTAGE / 100) << PAGE_SHIFT;
87 : : }
88 : :
89 : : #else
90 : :
91 : : static inline __maybe_unused phys_addr_t cma_early_percent_memory(void)
92 : : {
93 : : return 0;
94 : : }
95 : :
96 : : #endif
97 : :
98 : : /**
99 : : * dma_contiguous_reserve() - reserve area(s) for contiguous memory handling
100 : : * @limit: End address of the reserved memory (optional, 0 for any).
101 : : *
102 : : * This function reserves memory from early allocator. It should be
103 : : * called by arch specific code once the early allocator (memblock or bootmem)
104 : : * has been activated and all other subsystems have already allocated/reserved
105 : : * memory.
106 : : */
107 : 207 : void __init dma_contiguous_reserve(phys_addr_t limit)
108 : : {
109 : : phys_addr_t selected_size = 0;
110 : : phys_addr_t selected_base = 0;
111 : : phys_addr_t selected_limit = limit;
112 : : bool fixed = false;
113 : :
114 : : pr_debug("%s(limit %08lx)\n", __func__, (unsigned long)limit);
115 : :
116 [ - + ]: 207 : if (size_cmdline != -1) {
117 : : selected_size = size_cmdline;
118 : 0 : selected_base = base_cmdline;
119 [ # # # # ]: 0 : selected_limit = min_not_zero(limit_cmdline, limit);
120 [ # # ]: 0 : if (base_cmdline + size_cmdline == limit_cmdline)
121 : : fixed = true;
122 : : } else {
123 : : #ifdef CONFIG_CMA_SIZE_SEL_MBYTES
124 : : selected_size = size_bytes;
125 : : #elif defined(CONFIG_CMA_SIZE_SEL_PERCENTAGE)
126 : : selected_size = cma_early_percent_memory();
127 : : #elif defined(CONFIG_CMA_SIZE_SEL_MIN)
128 : : selected_size = min(size_bytes, cma_early_percent_memory());
129 : : #elif defined(CONFIG_CMA_SIZE_SEL_MAX)
130 : : selected_size = max(size_bytes, cma_early_percent_memory());
131 : : #endif
132 : : }
133 : :
134 [ + - - + ]: 207 : if (selected_size && !dma_contiguous_default_area) {
135 : : pr_debug("%s: reserving %ld MiB for global area\n", __func__,
136 : : (unsigned long)selected_size / SZ_1M);
137 : :
138 : 0 : dma_contiguous_reserve_area(selected_size, selected_base,
139 : : selected_limit,
140 : : &dma_contiguous_default_area,
141 : : fixed);
142 : : }
143 : 207 : }
144 : :
145 : : /**
146 : : * dma_contiguous_reserve_area() - reserve custom contiguous area
147 : : * @size: Size of the reserved area (in bytes),
148 : : * @base: Base address of the reserved area optional, use 0 for any
149 : : * @limit: End address of the reserved memory (optional, 0 for any).
150 : : * @res_cma: Pointer to store the created cma region.
151 : : * @fixed: hint about where to place the reserved area
152 : : *
153 : : * This function reserves memory from early allocator. It should be
154 : : * called by arch specific code once the early allocator (memblock or bootmem)
155 : : * has been activated and all other subsystems have already allocated/reserved
156 : : * memory. This function allows to create custom reserved areas for specific
157 : : * devices.
158 : : *
159 : : * If @fixed is true, reserve contiguous area at exactly @base. If false,
160 : : * reserve in range from @base to @limit.
161 : : */
162 : 0 : int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
163 : : phys_addr_t limit, struct cma **res_cma,
164 : : bool fixed)
165 : : {
166 : : int ret;
167 : :
168 : 0 : ret = cma_declare_contiguous(base, size, limit, 0, 0, fixed,
169 : : "reserved", res_cma);
170 [ # # ]: 0 : if (ret)
171 : : return ret;
172 : :
173 : : /* Architecture specific contiguous memory fixup. */
174 : 0 : dma_contiguous_early_fixup(cma_get_base(*res_cma),
175 : : cma_get_size(*res_cma));
176 : :
177 : 0 : return 0;
178 : : }
179 : :
180 : : /**
181 : : * dma_alloc_from_contiguous() - allocate pages from contiguous area
182 : : * @dev: Pointer to device for which the allocation is performed.
183 : : * @count: Requested number of pages.
184 : : * @align: Requested alignment of pages (in PAGE_SIZE order).
185 : : * @no_warn: Avoid printing message about failed allocation.
186 : : *
187 : : * This function allocates memory buffer for specified device. It uses
188 : : * device specific contiguous memory area if available or the default
189 : : * global one. Requires architecture specific dev_get_cma_area() helper
190 : : * function.
191 : : */
192 : 3726 : struct page *dma_alloc_from_contiguous(struct device *dev, size_t count,
193 : : unsigned int align, bool no_warn)
194 : : {
195 [ + + ]: 3726 : if (align > CONFIG_CMA_ALIGNMENT)
196 : : align = CONFIG_CMA_ALIGNMENT;
197 : :
198 : 3726 : return cma_alloc(dev_get_cma_area(dev), count, align, no_warn);
199 : : }
200 : :
201 : : /**
202 : : * dma_release_from_contiguous() - release allocated pages
203 : : * @dev: Pointer to device for which the pages were allocated.
204 : : * @pages: Allocated pages.
205 : : * @count: Number of allocated pages.
206 : : *
207 : : * This function releases memory allocated by dma_alloc_from_contiguous().
208 : : * It returns false when provided pages do not belong to contiguous area and
209 : : * true otherwise.
210 : : */
211 : 207 : bool dma_release_from_contiguous(struct device *dev, struct page *pages,
212 : : int count)
213 : : {
214 : 207 : return cma_release(dev_get_cma_area(dev), pages, count);
215 : : }
216 : :
217 : : /**
218 : : * dma_alloc_contiguous() - allocate contiguous pages
219 : : * @dev: Pointer to device for which the allocation is performed.
220 : : * @size: Requested allocation size.
221 : : * @gfp: Allocation flags.
222 : : *
223 : : * This function allocates contiguous memory buffer for specified device. It
224 : : * first tries to use device specific contiguous memory area if available or
225 : : * the default global one, then tries a fallback allocation of normal pages.
226 : : *
227 : : * Note that it byapss one-page size of allocations from the global area as
228 : : * the addresses within one page are always contiguous, so there is no need
229 : : * to waste CMA pages for that kind; it also helps reduce fragmentations.
230 : : */
231 : 0 : struct page *dma_alloc_contiguous(struct device *dev, size_t size, gfp_t gfp)
232 : : {
233 : 0 : size_t count = size >> PAGE_SHIFT;
234 : : struct page *page = NULL;
235 : : struct cma *cma = NULL;
236 : :
237 [ # # # # ]: 0 : if (dev && dev->cma_area)
238 : : cma = dev->cma_area;
239 [ # # ]: 0 : else if (count > 1)
240 : 0 : cma = dma_contiguous_default_area;
241 : :
242 : : /* CMA can be used only in the context which permits sleeping */
243 [ # # # # ]: 0 : if (cma && gfpflags_allow_blocking(gfp)) {
244 : 0 : size_t align = get_order(size);
245 : 0 : size_t cma_align = min_t(size_t, align, CONFIG_CMA_ALIGNMENT);
246 : :
247 : 0 : page = cma_alloc(cma, count, cma_align, gfp & __GFP_NOWARN);
248 : : }
249 : :
250 : 0 : return page;
251 : : }
252 : :
253 : : /**
254 : : * dma_free_contiguous() - release allocated pages
255 : : * @dev: Pointer to device for which the pages were allocated.
256 : : * @page: Pointer to the allocated pages.
257 : : * @size: Size of allocated pages.
258 : : *
259 : : * This function releases memory allocated by dma_alloc_contiguous(). As the
260 : : * cma_release returns false when provided pages do not belong to contiguous
261 : : * area and true otherwise, this function then does a fallback __free_pages()
262 : : * upon a false-return.
263 : : */
264 : 0 : void dma_free_contiguous(struct device *dev, struct page *page, size_t size)
265 : : {
266 [ # # ]: 0 : if (!cma_release(dev_get_cma_area(dev), page,
267 : 0 : PAGE_ALIGN(size) >> PAGE_SHIFT))
268 : 0 : __free_pages(page, get_order(size));
269 : 0 : }
270 : :
271 : : /*
272 : : * Support for reserved memory regions defined in device tree
273 : : */
274 : : #ifdef CONFIG_OF_RESERVED_MEM
275 : : #include <linux/of.h>
276 : : #include <linux/of_fdt.h>
277 : : #include <linux/of_reserved_mem.h>
278 : :
279 : : #undef pr_fmt
280 : : #define pr_fmt(fmt) fmt
281 : :
282 : 0 : static int rmem_cma_device_init(struct reserved_mem *rmem, struct device *dev)
283 : : {
284 : 0 : dev_set_cma_area(dev, rmem->priv);
285 : 0 : return 0;
286 : : }
287 : :
288 : 0 : static void rmem_cma_device_release(struct reserved_mem *rmem,
289 : : struct device *dev)
290 : : {
291 : : dev_set_cma_area(dev, NULL);
292 : 0 : }
293 : :
294 : : static const struct reserved_mem_ops rmem_cma_ops = {
295 : : .device_init = rmem_cma_device_init,
296 : : .device_release = rmem_cma_device_release,
297 : : };
298 : :
299 : 207 : static int __init rmem_cma_setup(struct reserved_mem *rmem)
300 : : {
301 : : phys_addr_t align = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order);
302 : : phys_addr_t mask = align - 1;
303 : 207 : unsigned long node = rmem->fdt_node;
304 : 207 : bool default_cma = of_get_flat_dt_prop(node, "linux,cma-default", NULL);
305 : : struct cma *cma;
306 : : int err;
307 : :
308 [ - + # # ]: 207 : if (size_cmdline != -1 && default_cma) {
309 : 0 : pr_info("Reserved memory: bypass %s node, using cmdline CMA params instead\n",
310 : : rmem->name);
311 : 0 : return -EBUSY;
312 : : }
313 : :
314 [ + - + - ]: 414 : if (!of_get_flat_dt_prop(node, "reusable", NULL) ||
315 : 207 : of_get_flat_dt_prop(node, "no-map", NULL))
316 : : return -EINVAL;
317 : :
318 [ + - - + ]: 207 : if ((rmem->base & mask) || (rmem->size & mask)) {
319 : 0 : pr_err("Reserved memory: incorrect alignment of CMA region\n");
320 : 0 : return -EINVAL;
321 : : }
322 : :
323 : 207 : err = cma_init_reserved_mem(rmem->base, rmem->size, 0, rmem->name, &cma);
324 [ - + ]: 207 : if (err) {
325 : 0 : pr_err("Reserved memory: unable to setup CMA region\n");
326 : 0 : return err;
327 : : }
328 : : /* Architecture specific contiguous memory fixup. */
329 : 207 : dma_contiguous_early_fixup(rmem->base, rmem->size);
330 : :
331 [ + - ]: 207 : if (default_cma)
332 : 207 : dma_contiguous_set_default(cma);
333 : :
334 : 207 : rmem->ops = &rmem_cma_ops;
335 : 207 : rmem->priv = cma;
336 : :
337 : 207 : pr_info("Reserved memory: created CMA memory pool at %pa, size %ld MiB\n",
338 : : &rmem->base, (unsigned long)rmem->size / SZ_1M);
339 : :
340 : 207 : return 0;
341 : : }
342 : : RESERVEDMEM_OF_DECLARE(cma, "shared-dma-pool", rmem_cma_setup);
343 : : #endif
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