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