// SPDX-License-Identifier: GPL-2.0+ /* * Contiguous Memory Allocator for DMA mapping framework * Copyright (c) 2010-2011 by Samsung Electronics. * Written by: * Marek Szyprowski * Michal Nazarewicz */ #define pr_fmt(fmt) "cma: " fmt #ifdef CONFIG_CMA_DEBUG #ifndef DEBUG # define DEBUG #endif #endif #include #include #include #include #include #include #include #ifdef CONFIG_CMA_SIZE_MBYTES #define CMA_SIZE_MBYTES CONFIG_CMA_SIZE_MBYTES #else #define CMA_SIZE_MBYTES 0 #endif struct cma *dma_contiguous_default_area; /* * Default global CMA area size can be defined in kernel's .config. * This is useful mainly for distro maintainers to create a kernel * that works correctly for most supported systems. * The size can be set in bytes or as a percentage of the total memory * in the system. * * Users, who want to set the size of global CMA area for their system * should use cma= kernel parameter. */ static const phys_addr_t size_bytes = (phys_addr_t)CMA_SIZE_MBYTES * SZ_1M; static phys_addr_t size_cmdline = -1; static phys_addr_t base_cmdline; static phys_addr_t limit_cmdline; static int __init early_cma(char *p) { if (!p) { pr_err("Config string not provided\n"); return -EINVAL; } size_cmdline = memparse(p, &p); if (*p != '@') return 0; base_cmdline = memparse(p + 1, &p); if (*p != '-') { limit_cmdline = base_cmdline + size_cmdline; return 0; } limit_cmdline = memparse(p + 1, &p); return 0; } early_param("cma", early_cma); #ifdef CONFIG_CMA_SIZE_PERCENTAGE static phys_addr_t __init __maybe_unused cma_early_percent_memory(void) { struct memblock_region *reg; unsigned long total_pages = 0; /* * We cannot use memblock_phys_mem_size() here, because * memblock_analyze() has not been called yet. */ for_each_memblock(memory, reg) total_pages += memblock_region_memory_end_pfn(reg) - memblock_region_memory_base_pfn(reg); return (total_pages * CONFIG_CMA_SIZE_PERCENTAGE / 100) << PAGE_SHIFT; } #else static inline __maybe_unused phys_addr_t cma_early_percent_memory(void) { return 0; } #endif /** * dma_contiguous_reserve() - reserve area(s) for contiguous memory handling * @limit: End address of the reserved memory (optional, 0 for any). * * This function reserves memory from early allocator. It should be * called by arch specific code once the early allocator (memblock or bootmem) * has been activated and all other subsystems have already allocated/reserved * memory. */ void __init dma_contiguous_reserve(phys_addr_t limit) { phys_addr_t selected_size = 0; phys_addr_t selected_base = 0; phys_addr_t selected_limit = limit; bool fixed = false; pr_debug("%s(limit %08lx)\n", __func__, (unsigned long)limit); if (size_cmdline != -1) { selected_size = size_cmdline; selected_base = base_cmdline; selected_limit = min_not_zero(limit_cmdline, limit); if (base_cmdline + size_cmdline == limit_cmdline) fixed = true; } else { #ifdef CONFIG_CMA_SIZE_SEL_MBYTES selected_size = size_bytes; #elif defined(CONFIG_CMA_SIZE_SEL_PERCENTAGE) selected_size = cma_early_percent_memory(); #elif defined(CONFIG_CMA_SIZE_SEL_MIN) selected_size = min(size_bytes, cma_early_percent_memory()); #elif defined(CONFIG_CMA_SIZE_SEL_MAX) selected_size = max(size_bytes, cma_early_percent_memory()); #endif } if (selected_size && !dma_contiguous_default_area) { pr_debug("%s: reserving %ld MiB for global area\n", __func__, (unsigned long)selected_size / SZ_1M); dma_contiguous_reserve_area(selected_size, selected_base, selected_limit, &dma_contiguous_default_area, fixed); } } /** * dma_contiguous_reserve_area() - reserve custom contiguous area * @size: Size of the reserved area (in bytes), * @base: Base address of the reserved area optional, use 0 for any * @limit: End address of the reserved memory (optional, 0 for any). * @res_cma: Pointer to store the created cma region. * @fixed: hint about where to place the reserved area * * This function reserves memory from early allocator. It should be * called by arch specific code once the early allocator (memblock or bootmem) * has been activated and all other subsystems have already allocated/reserved * memory. This function allows to create custom reserved areas for specific * devices. * * If @fixed is true, reserve contiguous area at exactly @base. If false, * reserve in range from @base to @limit. */ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base, phys_addr_t limit, struct cma **res_cma, bool fixed) { int ret; ret = cma_declare_contiguous(base, size, limit, 0, 0, fixed, "reserved", res_cma); if (ret) return ret; /* Architecture specific contiguous memory fixup. */ dma_contiguous_early_fixup(cma_get_base(*res_cma), cma_get_size(*res_cma)); return 0; } /** * dma_alloc_from_contiguous() - allocate pages from contiguous area * @dev: Pointer to device for which the allocation is performed. * @count: Requested number of pages. * @align: Requested alignment of pages (in PAGE_SIZE order). * @no_warn: Avoid printing message about failed allocation. * * This function allocates memory buffer for specified device. It uses * device specific contiguous memory area if available or the default * global one. Requires architecture specific dev_get_cma_area() helper * function. */ struct page *dma_alloc_from_contiguous(struct device *dev, size_t count, unsigned int align, bool no_warn) { if (align > CONFIG_CMA_ALIGNMENT) align = CONFIG_CMA_ALIGNMENT; return cma_alloc(dev_get_cma_area(dev), count, align, no_warn); } /** * dma_release_from_contiguous() - release allocated pages * @dev: Pointer to device for which the pages were allocated. * @pages: Allocated pages. * @count: Number of allocated pages. * * This function releases memory allocated by dma_alloc_from_contiguous(). * It returns false when provided pages do not belong to contiguous area and * true otherwise. */ bool dma_release_from_contiguous(struct device *dev, struct page *pages, int count) { return cma_release(dev_get_cma_area(dev), pages, count); } /** * dma_alloc_contiguous() - allocate contiguous pages * @dev: Pointer to device for which the allocation is performed. * @size: Requested allocation size. * @gfp: Allocation flags. * * This function allocates contiguous memory buffer for specified device. It * first tries to use device specific contiguous memory area if available or * the default global one, then tries a fallback allocation of normal pages. * * Note that it byapss one-page size of allocations from the global area as * the addresses within one page are always contiguous, so there is no need * to waste CMA pages for that kind; it also helps reduce fragmentations. */ struct page *dma_alloc_contiguous(struct device *dev, size_t size, gfp_t gfp) { size_t count = size >> PAGE_SHIFT; struct page *page = NULL; struct cma *cma = NULL; if (dev && dev->cma_area) cma = dev->cma_area; else if (count > 1) cma = dma_contiguous_default_area; /* CMA can be used only in the context which permits sleeping */ if (cma && gfpflags_allow_blocking(gfp)) { size_t align = get_order(size); size_t cma_align = min_t(size_t, align, CONFIG_CMA_ALIGNMENT); page = cma_alloc(cma, count, cma_align, gfp & __GFP_NOWARN); } return page; } /** * dma_free_contiguous() - release allocated pages * @dev: Pointer to device for which the pages were allocated. * @page: Pointer to the allocated pages. * @size: Size of allocated pages. * * This function releases memory allocated by dma_alloc_contiguous(). As the * cma_release returns false when provided pages do not belong to contiguous * area and true otherwise, this function then does a fallback __free_pages() * upon a false-return. */ void dma_free_contiguous(struct device *dev, struct page *page, size_t size) { if (!cma_release(dev_get_cma_area(dev), page, PAGE_ALIGN(size) >> PAGE_SHIFT)) __free_pages(page, get_order(size)); } /* * Support for reserved memory regions defined in device tree */ #ifdef CONFIG_OF_RESERVED_MEM #include #include #include #undef pr_fmt #define pr_fmt(fmt) fmt static int rmem_cma_device_init(struct reserved_mem *rmem, struct device *dev) { dev_set_cma_area(dev, rmem->priv); return 0; } static void rmem_cma_device_release(struct reserved_mem *rmem, struct device *dev) { dev_set_cma_area(dev, NULL); } static const struct reserved_mem_ops rmem_cma_ops = { .device_init = rmem_cma_device_init, .device_release = rmem_cma_device_release, }; static int __init rmem_cma_setup(struct reserved_mem *rmem) { phys_addr_t align = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order); phys_addr_t mask = align - 1; unsigned long node = rmem->fdt_node; struct cma *cma; int err; if (!of_get_flat_dt_prop(node, "reusable", NULL) || of_get_flat_dt_prop(node, "no-map", NULL)) return -EINVAL; if ((rmem->base & mask) || (rmem->size & mask)) { pr_err("Reserved memory: incorrect alignment of CMA region\n"); return -EINVAL; } err = cma_init_reserved_mem(rmem->base, rmem->size, 0, rmem->name, &cma); if (err) { pr_err("Reserved memory: unable to setup CMA region\n"); return err; } /* Architecture specific contiguous memory fixup. */ dma_contiguous_early_fixup(rmem->base, rmem->size); if (of_get_flat_dt_prop(node, "linux,cma-default", NULL)) dma_contiguous_set_default(cma); rmem->ops = &rmem_cma_ops; rmem->priv = cma; pr_info("Reserved memory: created CMA memory pool at %pa, size %ld MiB\n", &rmem->base, (unsigned long)rmem->size / SZ_1M); return 0; } RESERVEDMEM_OF_DECLARE(cma, "shared-dma-pool", rmem_cma_setup); #endif