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