124 lines
3 KiB
C
124 lines
3 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2012 ARM Ltd.
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* Copyright (C) 2020 Google LLC
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*/
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#include <linux/dma-direct.h>
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#include <linux/dma-noncoherent.h>
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#include <linux/dma-contiguous.h>
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#include <linux/init.h>
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#include <linux/genalloc.h>
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#include <linux/slab.h>
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static struct gen_pool *atomic_pool __ro_after_init;
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#define DEFAULT_DMA_COHERENT_POOL_SIZE SZ_256K
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static size_t atomic_pool_size __initdata = DEFAULT_DMA_COHERENT_POOL_SIZE;
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static int __init early_coherent_pool(char *p)
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{
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atomic_pool_size = memparse(p, &p);
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return 0;
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}
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early_param("coherent_pool", early_coherent_pool);
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static gfp_t dma_atomic_pool_gfp(void)
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{
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if (IS_ENABLED(CONFIG_ZONE_DMA))
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return GFP_DMA;
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if (IS_ENABLED(CONFIG_ZONE_DMA32))
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return GFP_DMA32;
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return GFP_KERNEL;
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}
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static int __init dma_atomic_pool_init(void)
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{
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unsigned int pool_size_order = get_order(atomic_pool_size);
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unsigned long nr_pages = atomic_pool_size >> PAGE_SHIFT;
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struct page *page;
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void *addr;
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int ret;
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if (dev_get_cma_area(NULL))
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page = dma_alloc_from_contiguous(NULL, nr_pages,
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pool_size_order, false);
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else
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page = alloc_pages(dma_atomic_pool_gfp(), pool_size_order);
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if (!page)
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goto out;
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arch_dma_prep_coherent(page, atomic_pool_size);
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atomic_pool = gen_pool_create(PAGE_SHIFT, -1);
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if (!atomic_pool)
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goto free_page;
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addr = dma_common_contiguous_remap(page, atomic_pool_size,
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pgprot_dmacoherent(PAGE_KERNEL),
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__builtin_return_address(0));
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if (!addr)
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goto destroy_genpool;
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ret = gen_pool_add_virt(atomic_pool, (unsigned long)addr,
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page_to_phys(page), atomic_pool_size, -1);
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if (ret)
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goto remove_mapping;
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gen_pool_set_algo(atomic_pool, gen_pool_first_fit_order_align, NULL);
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pr_info("DMA: preallocated %zu KiB pool for atomic allocations\n",
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atomic_pool_size / 1024);
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return 0;
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remove_mapping:
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dma_common_free_remap(addr, atomic_pool_size);
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destroy_genpool:
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gen_pool_destroy(atomic_pool);
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atomic_pool = NULL;
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free_page:
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if (!dma_release_from_contiguous(NULL, page, nr_pages))
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__free_pages(page, pool_size_order);
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out:
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pr_err("DMA: failed to allocate %zu KiB pool for atomic coherent allocation\n",
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atomic_pool_size / 1024);
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return -ENOMEM;
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}
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postcore_initcall(dma_atomic_pool_init);
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bool dma_in_atomic_pool(void *start, size_t size)
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{
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if (unlikely(!atomic_pool))
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return false;
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return gen_pool_has_addr(atomic_pool, (unsigned long)start, size);
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}
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void *dma_alloc_from_pool(size_t size, struct page **ret_page, gfp_t flags)
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{
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unsigned long val;
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void *ptr = NULL;
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if (!atomic_pool) {
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WARN(1, "coherent pool not initialised!\n");
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return NULL;
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}
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val = gen_pool_alloc(atomic_pool, size);
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if (val) {
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phys_addr_t phys = gen_pool_virt_to_phys(atomic_pool, val);
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*ret_page = pfn_to_page(__phys_to_pfn(phys));
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ptr = (void *)val;
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memset(ptr, 0, size);
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}
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return ptr;
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}
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bool dma_free_from_pool(void *start, size_t size)
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{
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if (!dma_in_atomic_pool(start, size))
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return false;
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gen_pool_free(atomic_pool, (unsigned long)start, size);
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return true;
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}
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