2020-04-14 18:04:52 -06:00
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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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2020-04-20 04:09:58 -06:00
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#include <linux/workqueue.h>
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2020-04-14 18:04:52 -06:00
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2020-04-14 18:04:55 -06:00
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static struct gen_pool *atomic_pool_dma __ro_after_init;
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static struct gen_pool *atomic_pool_dma32 __ro_after_init;
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static struct gen_pool *atomic_pool_kernel __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 = DEFAULT_DMA_COHERENT_POOL_SIZE;
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/* Dynamic background expansion when the atomic pool is near capacity */
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static struct work_struct atomic_pool_work;
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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 int atomic_pool_expand(struct gen_pool *pool, size_t pool_size,
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gfp_t gfp)
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{
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unsigned int order;
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struct page *page;
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void *addr;
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int ret = -ENOMEM;
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/* Cannot allocate larger than MAX_ORDER-1 */
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order = min(get_order(pool_size), MAX_ORDER-1);
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do {
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pool_size = 1 << (PAGE_SHIFT + order);
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if (dev_get_cma_area(NULL))
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page = dma_alloc_from_contiguous(NULL, 1 << order,
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order, false);
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else
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page = alloc_pages(gfp, order);
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} while (!page && order-- > 0);
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if (!page)
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goto out;
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2020-04-14 18:04:55 -06:00
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arch_dma_prep_coherent(page, pool_size);
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addr = dma_common_contiguous_remap(page, 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 free_page;
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ret = gen_pool_add_virt(pool, (unsigned long)addr, page_to_phys(page),
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pool_size, NUMA_NO_NODE);
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if (ret)
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goto remove_mapping;
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return 0;
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remove_mapping:
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dma_common_free_remap(addr, pool_size);
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free_page:
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if (!dma_release_from_contiguous(NULL, page, 1 << order))
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__free_pages(page, order);
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out:
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return ret;
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}
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static void atomic_pool_resize(struct gen_pool *pool, gfp_t gfp)
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{
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if (pool && gen_pool_avail(pool) < atomic_pool_size)
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atomic_pool_expand(pool, gen_pool_size(pool), gfp);
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}
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static void atomic_pool_work_fn(struct work_struct *work)
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{
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if (IS_ENABLED(CONFIG_ZONE_DMA))
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atomic_pool_resize(atomic_pool_dma,
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GFP_KERNEL | GFP_DMA);
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if (IS_ENABLED(CONFIG_ZONE_DMA32))
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atomic_pool_resize(atomic_pool_dma32,
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GFP_KERNEL | GFP_DMA32);
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atomic_pool_resize(atomic_pool_kernel, GFP_KERNEL);
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}
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static __init struct gen_pool *__dma_atomic_pool_init(size_t pool_size,
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gfp_t gfp)
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{
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struct gen_pool *pool;
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int ret;
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pool = gen_pool_create(PAGE_SHIFT, NUMA_NO_NODE);
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if (!pool)
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return NULL;
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gen_pool_set_algo(pool, gen_pool_first_fit_order_align, NULL);
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ret = atomic_pool_expand(pool, pool_size, gfp);
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if (ret) {
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gen_pool_destroy(pool);
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pr_err("DMA: failed to allocate %zu KiB %pGg pool for atomic allocation\n",
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pool_size >> 10, &gfp);
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return NULL;
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}
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pr_info("DMA: preallocated %zu KiB %pGg pool for atomic allocations\n",
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gen_pool_size(pool) >> 10, &gfp);
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return pool;
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}
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static int __init dma_atomic_pool_init(void)
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{
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int ret = 0;
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2020-04-20 04:09:58 -06:00
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INIT_WORK(&atomic_pool_work, atomic_pool_work_fn);
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atomic_pool_kernel = __dma_atomic_pool_init(atomic_pool_size,
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GFP_KERNEL);
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if (!atomic_pool_kernel)
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ret = -ENOMEM;
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if (IS_ENABLED(CONFIG_ZONE_DMA)) {
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atomic_pool_dma = __dma_atomic_pool_init(atomic_pool_size,
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GFP_KERNEL | GFP_DMA);
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if (!atomic_pool_dma)
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ret = -ENOMEM;
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}
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if (IS_ENABLED(CONFIG_ZONE_DMA32)) {
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atomic_pool_dma32 = __dma_atomic_pool_init(atomic_pool_size,
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GFP_KERNEL | GFP_DMA32);
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if (!atomic_pool_dma32)
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ret = -ENOMEM;
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}
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return ret;
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}
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postcore_initcall(dma_atomic_pool_init);
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static inline struct gen_pool *dev_to_pool(struct device *dev)
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{
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u64 phys_mask;
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gfp_t gfp;
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gfp = dma_direct_optimal_gfp_mask(dev, dev->coherent_dma_mask,
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&phys_mask);
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if (IS_ENABLED(CONFIG_ZONE_DMA) && gfp == GFP_DMA)
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return atomic_pool_dma;
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if (IS_ENABLED(CONFIG_ZONE_DMA32) && gfp == GFP_DMA32)
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return atomic_pool_dma32;
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return atomic_pool_kernel;
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}
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static bool dma_in_atomic_pool(struct device *dev, void *start, size_t size)
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{
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struct gen_pool *pool = dev_to_pool(dev);
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if (unlikely(!pool))
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return false;
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return gen_pool_has_addr(pool, (unsigned long)start, size);
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}
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void *dma_alloc_from_pool(struct device *dev, size_t size,
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struct page **ret_page, gfp_t flags)
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{
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struct gen_pool *pool = dev_to_pool(dev);
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unsigned long val;
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void *ptr = NULL;
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if (!pool) {
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WARN(1, "%pGg atomic pool not initialised!\n", &flags);
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return NULL;
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}
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val = gen_pool_alloc(pool, size);
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if (val) {
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phys_addr_t phys = gen_pool_virt_to_phys(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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if (gen_pool_avail(pool) < atomic_pool_size)
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schedule_work(&atomic_pool_work);
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return ptr;
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}
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bool dma_free_from_pool(struct device *dev, void *start, size_t size)
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{
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struct gen_pool *pool = dev_to_pool(dev);
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if (!dma_in_atomic_pool(dev, start, size))
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return false;
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gen_pool_free(pool, (unsigned long)start, size);
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return true;
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}
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