1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) 2012 ARM Ltd.
4 * Copyright (C) 2020 Google LLC
6 #include <linux/debugfs.h>
7 #include <linux/dma-direct.h>
8 #include <linux/dma-noncoherent.h>
9 #include <linux/dma-contiguous.h>
10 #include <linux/init.h>
11 #include <linux/genalloc.h>
12 #include <linux/set_memory.h>
13 #include <linux/slab.h>
14 #include <linux/workqueue.h>
16 static struct gen_pool *atomic_pool_dma __ro_after_init;
17 static unsigned long pool_size_dma;
18 static struct gen_pool *atomic_pool_dma32 __ro_after_init;
19 static unsigned long pool_size_dma32;
20 static struct gen_pool *atomic_pool_kernel __ro_after_init;
21 static unsigned long pool_size_kernel;
23 /* Size can be defined by the coherent_pool command line */
24 static size_t atomic_pool_size;
26 /* Dynamic background expansion when the atomic pool is near capacity */
27 static struct work_struct atomic_pool_work;
29 static int __init early_coherent_pool(char *p)
31 atomic_pool_size = memparse(p, &p);
34 early_param("coherent_pool", early_coherent_pool);
36 static void __init dma_atomic_pool_debugfs_init(void)
40 root = debugfs_create_dir("dma_pools", NULL);
41 if (IS_ERR_OR_NULL(root))
44 debugfs_create_ulong("pool_size_dma", 0400, root, &pool_size_dma);
45 debugfs_create_ulong("pool_size_dma32", 0400, root, &pool_size_dma32);
46 debugfs_create_ulong("pool_size_kernel", 0400, root, &pool_size_kernel);
49 static void dma_atomic_pool_size_add(gfp_t gfp, size_t size)
52 pool_size_dma += size;
53 else if (gfp & __GFP_DMA32)
54 pool_size_dma32 += size;
56 pool_size_kernel += size;
59 static int atomic_pool_expand(struct gen_pool *pool, size_t pool_size,
67 /* Cannot allocate larger than MAX_ORDER-1 */
68 order = min(get_order(pool_size), MAX_ORDER-1);
71 pool_size = 1 << (PAGE_SHIFT + order);
73 if (dev_get_cma_area(NULL))
74 page = dma_alloc_from_contiguous(NULL, 1 << order,
77 page = alloc_pages(gfp, order);
78 } while (!page && order-- > 0);
82 arch_dma_prep_coherent(page, pool_size);
84 #ifdef CONFIG_DMA_DIRECT_REMAP
85 addr = dma_common_contiguous_remap(page, pool_size,
86 pgprot_dmacoherent(PAGE_KERNEL),
87 __builtin_return_address(0));
91 addr = page_to_virt(page);
94 * Memory in the atomic DMA pools must be unencrypted, the pools do not
95 * shrink so no re-encryption occurs in dma_direct_free_pages().
97 ret = set_memory_decrypted((unsigned long)page_to_virt(page),
101 ret = gen_pool_add_virt(pool, (unsigned long)addr, page_to_phys(page),
102 pool_size, NUMA_NO_NODE);
104 goto encrypt_mapping;
106 dma_atomic_pool_size_add(gfp, pool_size);
110 ret = set_memory_encrypted((unsigned long)page_to_virt(page),
112 if (WARN_ON_ONCE(ret)) {
113 /* Decrypt succeeded but encrypt failed, purposely leak */
117 #ifdef CONFIG_DMA_DIRECT_REMAP
118 dma_common_free_remap(addr, pool_size);
120 free_page: __maybe_unused
121 if (!dma_release_from_contiguous(NULL, page, 1 << order))
122 __free_pages(page, order);
127 static void atomic_pool_resize(struct gen_pool *pool, gfp_t gfp)
129 if (pool && gen_pool_avail(pool) < atomic_pool_size)
130 atomic_pool_expand(pool, gen_pool_size(pool), gfp);
133 static void atomic_pool_work_fn(struct work_struct *work)
135 if (IS_ENABLED(CONFIG_ZONE_DMA))
136 atomic_pool_resize(atomic_pool_dma,
137 GFP_KERNEL | GFP_DMA);
138 if (IS_ENABLED(CONFIG_ZONE_DMA32))
139 atomic_pool_resize(atomic_pool_dma32,
140 GFP_KERNEL | GFP_DMA32);
141 atomic_pool_resize(atomic_pool_kernel, GFP_KERNEL);
144 static __init struct gen_pool *__dma_atomic_pool_init(size_t pool_size,
147 struct gen_pool *pool;
150 pool = gen_pool_create(PAGE_SHIFT, NUMA_NO_NODE);
154 gen_pool_set_algo(pool, gen_pool_first_fit_order_align, NULL);
156 ret = atomic_pool_expand(pool, pool_size, gfp);
158 gen_pool_destroy(pool);
159 pr_err("DMA: failed to allocate %zu KiB %pGg pool for atomic allocation\n",
160 pool_size >> 10, &gfp);
164 pr_info("DMA: preallocated %zu KiB %pGg pool for atomic allocations\n",
165 gen_pool_size(pool) >> 10, &gfp);
169 static int __init dma_atomic_pool_init(void)
174 * If coherent_pool was not used on the command line, default the pool
175 * sizes to 128KB per 1GB of memory, min 128KB, max MAX_ORDER-1.
177 if (!atomic_pool_size) {
178 unsigned long pages = totalram_pages() / (SZ_1G / SZ_128K);
179 pages = min_t(unsigned long, pages, MAX_ORDER_NR_PAGES);
180 atomic_pool_size = max_t(size_t, pages << PAGE_SHIFT, SZ_128K);
182 INIT_WORK(&atomic_pool_work, atomic_pool_work_fn);
184 atomic_pool_kernel = __dma_atomic_pool_init(atomic_pool_size,
186 if (!atomic_pool_kernel)
188 if (IS_ENABLED(CONFIG_ZONE_DMA)) {
189 atomic_pool_dma = __dma_atomic_pool_init(atomic_pool_size,
190 GFP_KERNEL | GFP_DMA);
191 if (!atomic_pool_dma)
194 if (IS_ENABLED(CONFIG_ZONE_DMA32)) {
195 atomic_pool_dma32 = __dma_atomic_pool_init(atomic_pool_size,
196 GFP_KERNEL | GFP_DMA32);
197 if (!atomic_pool_dma32)
201 dma_atomic_pool_debugfs_init();
204 postcore_initcall(dma_atomic_pool_init);
206 static inline struct gen_pool *dev_to_pool(struct device *dev)
211 gfp = dma_direct_optimal_gfp_mask(dev, dev->coherent_dma_mask,
213 if (IS_ENABLED(CONFIG_ZONE_DMA) && gfp == GFP_DMA)
214 return atomic_pool_dma;
215 if (IS_ENABLED(CONFIG_ZONE_DMA32) && gfp == GFP_DMA32)
216 return atomic_pool_dma32;
217 return atomic_pool_kernel;
220 static bool dma_in_atomic_pool(struct device *dev, void *start, size_t size)
222 struct gen_pool *pool = dev_to_pool(dev);
226 return gen_pool_has_addr(pool, (unsigned long)start, size);
229 void *dma_alloc_from_pool(struct device *dev, size_t size,
230 struct page **ret_page, gfp_t flags)
232 struct gen_pool *pool = dev_to_pool(dev);
237 WARN(1, "%pGg atomic pool not initialised!\n", &flags);
241 val = gen_pool_alloc(pool, size);
243 phys_addr_t phys = gen_pool_virt_to_phys(pool, val);
245 *ret_page = pfn_to_page(__phys_to_pfn(phys));
247 memset(ptr, 0, size);
249 WARN_ONCE(1, "DMA coherent pool depleted, increase size "
250 "(recommended min coherent_pool=%zuK)\n",
251 gen_pool_size(pool) >> 9);
253 if (gen_pool_avail(pool) < atomic_pool_size)
254 schedule_work(&atomic_pool_work);
259 bool dma_free_from_pool(struct device *dev, void *start, size_t size)
261 struct gen_pool *pool = dev_to_pool(dev);
263 if (!dma_in_atomic_pool(dev, start, size))
265 gen_pool_free(pool, (unsigned long)start, size);