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1/*
2 * Contiguous Memory Allocator for DMA mapping framework
3 * Copyright (c) 2010-2011 by Samsung Electronics.
4 * Written by:
5 * Marek Szyprowski <m.szyprowski@samsung.com>
6 * Michal Nazarewicz <mina86@mina86.com>
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License as
10 * published by the Free Software Foundation; either version 2 of the
11 * License or (at your optional) any later version of the license.
12 */
13
14#define pr_fmt(fmt) "cma: " fmt
15
16#ifdef CONFIG_CMA_DEBUG
17#ifndef DEBUG
18# define DEBUG
19#endif
20#endif
21
22#include <asm/page.h>
23#include <asm/dma-contiguous.h>
24
25#include <linux/memblock.h>
26#include <linux/err.h>
27#include <linux/mm.h>
28#include <linux/mutex.h>
29#include <linux/page-isolation.h>
30#include <linux/sizes.h>
31#include <linux/slab.h>
32#include <linux/swap.h>
33#include <linux/mm_types.h>
34#include <linux/dma-contiguous.h>
35
36struct cma {
37 unsigned long base_pfn;
38 unsigned long count;
39 unsigned long *bitmap;
40};
41
42struct cma *dma_contiguous_default_area;
43
44#ifdef CONFIG_CMA_SIZE_MBYTES
45#define CMA_SIZE_MBYTES CONFIG_CMA_SIZE_MBYTES
46#else
47#define CMA_SIZE_MBYTES 0
48#endif
49
50/*
51 * Default global CMA area size can be defined in kernel's .config.
52 * This is useful mainly for distro maintainers to create a kernel
53 * that works correctly for most supported systems.
54 * The size can be set in bytes or as a percentage of the total memory
55 * in the system.
56 *
57 * Users, who want to set the size of global CMA area for their system
58 * should use cma= kernel parameter.
59 */
60static const phys_addr_t size_bytes = CMA_SIZE_MBYTES * SZ_1M;
61static phys_addr_t size_cmdline = -1;
62
63static int __init early_cma(char *p)
64{
65 pr_debug("%s(%s)\n", __func__, p);
66 size_cmdline = memparse(p, &p);
67 return 0;
68}
69early_param("cma", early_cma);
70
71#ifdef CONFIG_CMA_SIZE_PERCENTAGE
72
73static 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
91static 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 */
107void __init dma_contiguous_reserve(phys_addr_t limit)
108{
109 phys_addr_t selected_size = 0;
110
111 pr_debug("%s(limit %08lx)\n", __func__, (unsigned long)limit);
112
113 if (size_cmdline != -1) {
114 selected_size = size_cmdline;
115 } else {
116#ifdef CONFIG_CMA_SIZE_SEL_MBYTES
117 selected_size = size_bytes;
118#elif defined(CONFIG_CMA_SIZE_SEL_PERCENTAGE)
119 selected_size = cma_early_percent_memory();
120#elif defined(CONFIG_CMA_SIZE_SEL_MIN)
121 selected_size = min(size_bytes, cma_early_percent_memory());
122#elif defined(CONFIG_CMA_SIZE_SEL_MAX)
123 selected_size = max(size_bytes, cma_early_percent_memory());
124#endif
125 }
126
127 if (selected_size && !dma_contiguous_default_area) {
128 pr_debug("%s: reserving %ld MiB for global area\n", __func__,
129 (unsigned long)selected_size / SZ_1M);
130
131 dma_contiguous_reserve_area(selected_size, 0, limit,
132 &dma_contiguous_default_area);
133 }
134};
135
136static DEFINE_MUTEX(cma_mutex);
137
138static int __init cma_activate_area(struct cma *cma)
139{
140 int bitmap_size = BITS_TO_LONGS(cma->count) * sizeof(long);
141 unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
142 unsigned i = cma->count >> pageblock_order;
143 struct zone *zone;
144
145 cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
146
147 if (!cma->bitmap)
148 return -ENOMEM;
149
150 WARN_ON_ONCE(!pfn_valid(pfn));
151 zone = page_zone(pfn_to_page(pfn));
152
153 do {
154 unsigned j;
155 base_pfn = pfn;
156 for (j = pageblock_nr_pages; j; --j, pfn++) {
157 WARN_ON_ONCE(!pfn_valid(pfn));
158 if (page_zone(pfn_to_page(pfn)) != zone)
159 return -EINVAL;
160 }
161 init_cma_reserved_pageblock(pfn_to_page(base_pfn));
162 } while (--i);
163
164 return 0;
165}
166
167static struct cma cma_areas[MAX_CMA_AREAS];
168static unsigned cma_area_count;
169
170static int __init cma_init_reserved_areas(void)
171{
172 int i;
173
174 for (i = 0; i < cma_area_count; i++) {
175 int ret = cma_activate_area(&cma_areas[i]);
176 if (ret)
177 return ret;
178 }
179
180 return 0;
181}
182core_initcall(cma_init_reserved_areas);
183
184/**
185 * dma_contiguous_reserve_area() - reserve custom contiguous area
186 * @size: Size of the reserved area (in bytes),
187 * @base: Base address of the reserved area optional, use 0 for any
188 * @limit: End address of the reserved memory (optional, 0 for any).
189 * @res_cma: Pointer to store the created cma region.
190 *
191 * This function reserves memory from early allocator. It should be
192 * called by arch specific code once the early allocator (memblock or bootmem)
193 * has been activated and all other subsystems have already allocated/reserved
194 * memory. This function allows to create custom reserved areas for specific
195 * devices.
196 */
197int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
198 phys_addr_t limit, struct cma **res_cma)
199{
200 struct cma *cma = &cma_areas[cma_area_count];
201 phys_addr_t alignment;
202 int ret = 0;
203
204 pr_debug("%s(size %lx, base %08lx, limit %08lx)\n", __func__,
205 (unsigned long)size, (unsigned long)base,
206 (unsigned long)limit);
207
208 /* Sanity checks */
209 if (cma_area_count == ARRAY_SIZE(cma_areas)) {
210 pr_err("Not enough slots for CMA reserved regions!\n");
211 return -ENOSPC;
212 }
213
214 if (!size)
215 return -EINVAL;
216
217 /* Sanitise input arguments */
218 alignment = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order);
219 base = ALIGN(base, alignment);
220 size = ALIGN(size, alignment);
221 limit &= ~(alignment - 1);
222
223 /* Reserve memory */
224 if (base) {
225 if (memblock_is_region_reserved(base, size) ||
226 memblock_reserve(base, size) < 0) {
227 ret = -EBUSY;
228 goto err;
229 }
230 } else {
231 /*
232 * Use __memblock_alloc_base() since
233 * memblock_alloc_base() panic()s.
234 */
235 phys_addr_t addr = __memblock_alloc_base(size, alignment, limit);
236 if (!addr) {
237 ret = -ENOMEM;
238 goto err;
239 } else {
240 base = addr;
241 }
242 }
243
244 /*
245 * Each reserved area must be initialised later, when more kernel
246 * subsystems (like slab allocator) are available.
247 */
248 cma->base_pfn = PFN_DOWN(base);
249 cma->count = size >> PAGE_SHIFT;
250 *res_cma = cma;
251 cma_area_count++;
252
253 pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
254 (unsigned long)base);
255
256 /* Architecture specific contiguous memory fixup. */
257 dma_contiguous_early_fixup(base, size);
258 return 0;
259err:
260 pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
261 return ret;
262}
263
264/**
265 * dma_alloc_from_contiguous() - allocate pages from contiguous area
266 * @dev: Pointer to device for which the allocation is performed.
267 * @count: Requested number of pages.
268 * @align: Requested alignment of pages (in PAGE_SIZE order).
269 *
270 * This function allocates memory buffer for specified device. It uses
271 * device specific contiguous memory area if available or the default
272 * global one. Requires architecture specific get_dev_cma_area() helper
273 * function.
274 */
275struct page *dma_alloc_from_contiguous(struct device *dev, int count,
276 unsigned int align)
277{
278 unsigned long mask, pfn, pageno, start = 0;
279 struct cma *cma = dev_get_cma_area(dev);
280 struct page *page = NULL;
281 int ret;
282
283 if (!cma || !cma->count)
284 return NULL;
285
286 if (align > CONFIG_CMA_ALIGNMENT)
287 align = CONFIG_CMA_ALIGNMENT;
288
289 pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
290 count, align);
291
292 if (!count)
293 return NULL;
294
295 mask = (1 << align) - 1;
296
297 mutex_lock(&cma_mutex);
298
299 for (;;) {
300 pageno = bitmap_find_next_zero_area(cma->bitmap, cma->count,
301 start, count, mask);
302 if (pageno >= cma->count)
303 break;
304
305 pfn = cma->base_pfn + pageno;
306 ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
307 if (ret == 0) {
308 bitmap_set(cma->bitmap, pageno, count);
309 page = pfn_to_page(pfn);
310 break;
311 } else if (ret != -EBUSY) {
312 break;
313 }
314 pr_debug("%s(): memory range at %p is busy, retrying\n",
315 __func__, pfn_to_page(pfn));
316 /* try again with a bit different memory target */
317 start = pageno + mask + 1;
318 }
319
320 mutex_unlock(&cma_mutex);
321 pr_debug("%s(): returned %p\n", __func__, page);
322 return page;
323}
324
325/**
326 * dma_release_from_contiguous() - release allocated pages
327 * @dev: Pointer to device for which the pages were allocated.
328 * @pages: Allocated pages.
329 * @count: Number of allocated pages.
330 *
331 * This function releases memory allocated by dma_alloc_from_contiguous().
332 * It returns false when provided pages do not belong to contiguous area and
333 * true otherwise.
334 */
335bool dma_release_from_contiguous(struct device *dev, struct page *pages,
336 int count)
337{
338 struct cma *cma = dev_get_cma_area(dev);
339 unsigned long pfn;
340
341 if (!cma || !pages)
342 return false;
343
344 pr_debug("%s(page %p)\n", __func__, (void *)pages);
345
346 pfn = page_to_pfn(pages);
347
348 if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
349 return false;
350
351 VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
352
353 mutex_lock(&cma_mutex);
354 bitmap_clear(cma->bitmap, pfn - cma->base_pfn, count);
355 free_contig_range(pfn, count);
356 mutex_unlock(&cma_mutex);
357
358 return true;
359}
1/*
2 * Contiguous Memory Allocator for DMA mapping framework
3 * Copyright (c) 2010-2011 by Samsung Electronics.
4 * Written by:
5 * Marek Szyprowski <m.szyprowski@samsung.com>
6 * Michal Nazarewicz <mina86@mina86.com>
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License as
10 * published by the Free Software Foundation; either version 2 of the
11 * License or (at your optional) any later version of the license.
12 */
13
14#define pr_fmt(fmt) "cma: " fmt
15
16#ifdef CONFIG_CMA_DEBUG
17#ifndef DEBUG
18# define DEBUG
19#endif
20#endif
21
22#include <asm/page.h>
23#include <asm/dma-contiguous.h>
24
25#include <linux/memblock.h>
26#include <linux/err.h>
27#include <linux/sizes.h>
28#include <linux/dma-contiguous.h>
29#include <linux/cma.h>
30
31#ifdef CONFIG_CMA_SIZE_MBYTES
32#define CMA_SIZE_MBYTES CONFIG_CMA_SIZE_MBYTES
33#else
34#define CMA_SIZE_MBYTES 0
35#endif
36
37struct cma *dma_contiguous_default_area;
38
39/*
40 * Default global CMA area size can be defined in kernel's .config.
41 * This is useful mainly for distro maintainers to create a kernel
42 * that works correctly for most supported systems.
43 * The size can be set in bytes or as a percentage of the total memory
44 * in the system.
45 *
46 * Users, who want to set the size of global CMA area for their system
47 * should use cma= kernel parameter.
48 */
49static const phys_addr_t size_bytes = (phys_addr_t)CMA_SIZE_MBYTES * SZ_1M;
50static phys_addr_t size_cmdline = -1;
51static phys_addr_t base_cmdline;
52static phys_addr_t limit_cmdline;
53
54static int __init early_cma(char *p)
55{
56 pr_debug("%s(%s)\n", __func__, p);
57 size_cmdline = memparse(p, &p);
58 if (*p != '@')
59 return 0;
60 base_cmdline = memparse(p + 1, &p);
61 if (*p != '-') {
62 limit_cmdline = base_cmdline + size_cmdline;
63 return 0;
64 }
65 limit_cmdline = memparse(p + 1, &p);
66
67 return 0;
68}
69early_param("cma", early_cma);
70
71#ifdef CONFIG_CMA_SIZE_PERCENTAGE
72
73static 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
91static 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 */
107void __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 if (size_cmdline != -1) {
117 selected_size = size_cmdline;
118 selected_base = base_cmdline;
119 selected_limit = min_not_zero(limit_cmdline, limit);
120 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 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 dma_contiguous_reserve_area(selected_size, selected_base,
139 selected_limit,
140 &dma_contiguous_default_area,
141 fixed);
142 }
143}
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 */
162int __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 ret = cma_declare_contiguous(base, size, limit, 0, 0, fixed, res_cma);
169 if (ret)
170 return ret;
171
172 /* Architecture specific contiguous memory fixup. */
173 dma_contiguous_early_fixup(cma_get_base(*res_cma),
174 cma_get_size(*res_cma));
175
176 return 0;
177}
178
179/**
180 * dma_alloc_from_contiguous() - allocate pages from contiguous area
181 * @dev: Pointer to device for which the allocation is performed.
182 * @count: Requested number of pages.
183 * @align: Requested alignment of pages (in PAGE_SIZE order).
184 *
185 * This function allocates memory buffer for specified device. It uses
186 * device specific contiguous memory area if available or the default
187 * global one. Requires architecture specific dev_get_cma_area() helper
188 * function.
189 */
190struct page *dma_alloc_from_contiguous(struct device *dev, size_t count,
191 unsigned int align)
192{
193 if (align > CONFIG_CMA_ALIGNMENT)
194 align = CONFIG_CMA_ALIGNMENT;
195
196 return cma_alloc(dev_get_cma_area(dev), count, align);
197}
198
199/**
200 * dma_release_from_contiguous() - release allocated pages
201 * @dev: Pointer to device for which the pages were allocated.
202 * @pages: Allocated pages.
203 * @count: Number of allocated pages.
204 *
205 * This function releases memory allocated by dma_alloc_from_contiguous().
206 * It returns false when provided pages do not belong to contiguous area and
207 * true otherwise.
208 */
209bool dma_release_from_contiguous(struct device *dev, struct page *pages,
210 int count)
211{
212 return cma_release(dev_get_cma_area(dev), pages, count);
213}
214
215/*
216 * Support for reserved memory regions defined in device tree
217 */
218#ifdef CONFIG_OF_RESERVED_MEM
219#include <linux/of.h>
220#include <linux/of_fdt.h>
221#include <linux/of_reserved_mem.h>
222
223#undef pr_fmt
224#define pr_fmt(fmt) fmt
225
226static int rmem_cma_device_init(struct reserved_mem *rmem, struct device *dev)
227{
228 dev_set_cma_area(dev, rmem->priv);
229 return 0;
230}
231
232static void rmem_cma_device_release(struct reserved_mem *rmem,
233 struct device *dev)
234{
235 dev_set_cma_area(dev, NULL);
236}
237
238static const struct reserved_mem_ops rmem_cma_ops = {
239 .device_init = rmem_cma_device_init,
240 .device_release = rmem_cma_device_release,
241};
242
243static int __init rmem_cma_setup(struct reserved_mem *rmem)
244{
245 phys_addr_t align = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order);
246 phys_addr_t mask = align - 1;
247 unsigned long node = rmem->fdt_node;
248 struct cma *cma;
249 int err;
250
251 if (!of_get_flat_dt_prop(node, "reusable", NULL) ||
252 of_get_flat_dt_prop(node, "no-map", NULL))
253 return -EINVAL;
254
255 if ((rmem->base & mask) || (rmem->size & mask)) {
256 pr_err("Reserved memory: incorrect alignment of CMA region\n");
257 return -EINVAL;
258 }
259
260 err = cma_init_reserved_mem(rmem->base, rmem->size, 0, &cma);
261 if (err) {
262 pr_err("Reserved memory: unable to setup CMA region\n");
263 return err;
264 }
265 /* Architecture specific contiguous memory fixup. */
266 dma_contiguous_early_fixup(rmem->base, rmem->size);
267
268 if (of_get_flat_dt_prop(node, "linux,cma-default", NULL))
269 dma_contiguous_set_default(cma);
270
271 rmem->ops = &rmem_cma_ops;
272 rmem->priv = cma;
273
274 pr_info("Reserved memory: created CMA memory pool at %pa, size %ld MiB\n",
275 &rmem->base, (unsigned long)rmem->size / SZ_1M);
276
277 return 0;
278}
279RESERVEDMEM_OF_DECLARE(cma, "shared-dma-pool", rmem_cma_setup);
280#endif