| // SPDX-License-Identifier: GPL-2.0+ |
| /* |
| * Contiguous Memory Allocator for DMA mapping framework |
| * Copyright (c) 2010-2011 by Samsung Electronics. |
| * Written by: |
| * Marek Szyprowski <m.szyprowski@samsung.com> |
| * Michal Nazarewicz <mina86@mina86.com> |
| * |
| * Contiguous Memory Allocator |
| * |
| * The Contiguous Memory Allocator (CMA) makes it possible to |
| * allocate big contiguous chunks of memory after the system has |
| * booted. |
| * |
| * Why is it needed? |
| * |
| * Various devices on embedded systems have no scatter-getter and/or |
| * IO map support and require contiguous blocks of memory to |
| * operate. They include devices such as cameras, hardware video |
| * coders, etc. |
| * |
| * Such devices often require big memory buffers (a full HD frame |
| * is, for instance, more than 2 mega pixels large, i.e. more than 6 |
| * MB of memory), which makes mechanisms such as kmalloc() or |
| * alloc_page() ineffective. |
| * |
| * At the same time, a solution where a big memory region is |
| * reserved for a device is suboptimal since often more memory is |
| * reserved then strictly required and, moreover, the memory is |
| * inaccessible to page system even if device drivers don't use it. |
| * |
| * CMA tries to solve this issue by operating on memory regions |
| * where only movable pages can be allocated from. This way, kernel |
| * can use the memory for pagecache and when device driver requests |
| * it, allocated pages can be migrated. |
| */ |
| |
| #define pr_fmt(fmt) "cma: " fmt |
| |
| #ifdef CONFIG_CMA_DEBUG |
| #ifndef DEBUG |
| # define DEBUG |
| #endif |
| #endif |
| |
| #include <asm/page.h> |
| |
| #include <linux/memblock.h> |
| #include <linux/err.h> |
| #include <linux/sizes.h> |
| #include <linux/dma-map-ops.h> |
| #include <linux/cma.h> |
| #include <linux/nospec.h> |
| |
| #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; |
| EXPORT_SYMBOL_GPL(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 __initconst = |
| (phys_addr_t)CMA_SIZE_MBYTES * SZ_1M; |
| static phys_addr_t size_cmdline __initdata = -1; |
| static phys_addr_t base_cmdline __initdata; |
| static phys_addr_t limit_cmdline __initdata; |
| |
| 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_DMA_NUMA_CMA |
| |
| static struct cma *dma_contiguous_numa_area[MAX_NUMNODES]; |
| static phys_addr_t numa_cma_size[MAX_NUMNODES] __initdata; |
| static struct cma *dma_contiguous_pernuma_area[MAX_NUMNODES]; |
| static phys_addr_t pernuma_size_bytes __initdata; |
| |
| static int __init early_numa_cma(char *p) |
| { |
| int nid, count = 0; |
| unsigned long tmp; |
| char *s = p; |
| |
| while (*s) { |
| if (sscanf(s, "%lu%n", &tmp, &count) != 1) |
| break; |
| |
| if (s[count] == ':') { |
| if (tmp >= MAX_NUMNODES) |
| break; |
| nid = array_index_nospec(tmp, MAX_NUMNODES); |
| |
| s += count + 1; |
| tmp = memparse(s, &s); |
| numa_cma_size[nid] = tmp; |
| |
| if (*s == ',') |
| s++; |
| else |
| break; |
| } else |
| break; |
| } |
| |
| return 0; |
| } |
| early_param("numa_cma", early_numa_cma); |
| |
| static int __init early_cma_pernuma(char *p) |
| { |
| pernuma_size_bytes = memparse(p, &p); |
| return 0; |
| } |
| early_param("cma_pernuma", early_cma_pernuma); |
| #endif |
| |
| #ifdef CONFIG_CMA_SIZE_PERCENTAGE |
| |
| static phys_addr_t __init __maybe_unused cma_early_percent_memory(void) |
| { |
| unsigned long total_pages = PHYS_PFN(memblock_phys_mem_size()); |
| |
| 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 |
| |
| #ifdef CONFIG_DMA_NUMA_CMA |
| static void __init dma_numa_cma_reserve(void) |
| { |
| int nid; |
| |
| for_each_node(nid) { |
| int ret; |
| char name[CMA_MAX_NAME]; |
| struct cma **cma; |
| |
| if (!node_online(nid)) { |
| if (pernuma_size_bytes || numa_cma_size[nid]) |
| pr_warn("invalid node %d specified\n", nid); |
| continue; |
| } |
| |
| if (pernuma_size_bytes) { |
| |
| cma = &dma_contiguous_pernuma_area[nid]; |
| snprintf(name, sizeof(name), "pernuma%d", nid); |
| ret = cma_declare_contiguous_nid(0, pernuma_size_bytes, 0, 0, |
| 0, false, name, cma, nid); |
| if (ret) |
| pr_warn("%s: reservation failed: err %d, node %d", __func__, |
| ret, nid); |
| } |
| |
| if (numa_cma_size[nid]) { |
| |
| cma = &dma_contiguous_numa_area[nid]; |
| snprintf(name, sizeof(name), "numa%d", nid); |
| ret = cma_declare_contiguous_nid(0, numa_cma_size[nid], 0, 0, 0, false, |
| name, cma, nid); |
| if (ret) |
| pr_warn("%s: reservation failed: err %d, node %d", __func__, |
| ret, nid); |
| } |
| } |
| } |
| #else |
| static inline void __init dma_numa_cma_reserve(void) |
| { |
| } |
| #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; |
| |
| dma_numa_cma_reserve(); |
| |
| 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); |
| } |
| } |
| |
| void __weak |
| dma_contiguous_early_fixup(phys_addr_t base, unsigned long size) |
| { |
| } |
| |
| /** |
| * 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); |
| } |
| |
| static struct page *cma_alloc_aligned(struct cma *cma, size_t size, gfp_t gfp) |
| { |
| unsigned int align = min(get_order(size), CONFIG_CMA_ALIGNMENT); |
| |
| return cma_alloc(cma, size >> PAGE_SHIFT, align, gfp & __GFP_NOWARN); |
| } |
| |
| /** |
| * dma_alloc_contiguous() - allocate contiguous pages |
| * @dev: Pointer to device for which the allocation is performed. |
| * @size: Requested allocation size. |
| * @gfp: Allocation flags. |
| * |
| * tries to use device specific contiguous memory area if available, or it |
| * tries to use per-numa cma, if the allocation fails, it will fallback to |
| * try default global one. |
| * |
| * Note that it bypass one-page size of allocations from the per-numa and |
| * 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) |
| { |
| #ifdef CONFIG_DMA_NUMA_CMA |
| int nid = dev_to_node(dev); |
| #endif |
| |
| /* CMA can be used only in the context which permits sleeping */ |
| if (!gfpflags_allow_blocking(gfp)) |
| return NULL; |
| if (dev->cma_area) |
| return cma_alloc_aligned(dev->cma_area, size, gfp); |
| if (size <= PAGE_SIZE) |
| return NULL; |
| |
| #ifdef CONFIG_DMA_NUMA_CMA |
| if (nid != NUMA_NO_NODE && !(gfp & (GFP_DMA | GFP_DMA32))) { |
| struct cma *cma = dma_contiguous_pernuma_area[nid]; |
| struct page *page; |
| |
| if (cma) { |
| page = cma_alloc_aligned(cma, size, gfp); |
| if (page) |
| return page; |
| } |
| |
| cma = dma_contiguous_numa_area[nid]; |
| if (cma) { |
| page = cma_alloc_aligned(cma, size, gfp); |
| if (page) |
| return page; |
| } |
| } |
| #endif |
| if (!dma_contiguous_default_area) |
| return NULL; |
| |
| return cma_alloc_aligned(dma_contiguous_default_area, size, gfp); |
| } |
| |
| /** |
| * 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) |
| { |
| unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT; |
| |
| /* if dev has its own cma, free page from there */ |
| if (dev->cma_area) { |
| if (cma_release(dev->cma_area, page, count)) |
| return; |
| } else { |
| /* |
| * otherwise, page is from either per-numa cma or default cma |
| */ |
| #ifdef CONFIG_DMA_NUMA_CMA |
| if (cma_release(dma_contiguous_pernuma_area[page_to_nid(page)], |
| page, count)) |
| return; |
| if (cma_release(dma_contiguous_numa_area[page_to_nid(page)], |
| page, count)) |
| return; |
| #endif |
| if (cma_release(dma_contiguous_default_area, page, count)) |
| return; |
| } |
| |
| /* not in any cma, free from buddy */ |
| __free_pages(page, get_order(size)); |
| } |
| |
| /* |
| * Support for reserved memory regions defined in device tree |
| */ |
| #ifdef CONFIG_OF_RESERVED_MEM |
| #include <linux/of.h> |
| #include <linux/of_fdt.h> |
| #include <linux/of_reserved_mem.h> |
| |
| #undef pr_fmt |
| #define pr_fmt(fmt) fmt |
| |
| static int rmem_cma_device_init(struct reserved_mem *rmem, struct device *dev) |
| { |
| dev->cma_area = rmem->priv; |
| return 0; |
| } |
| |
| static void rmem_cma_device_release(struct reserved_mem *rmem, |
| struct device *dev) |
| { |
| dev->cma_area = 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) |
| { |
| unsigned long node = rmem->fdt_node; |
| bool default_cma = of_get_flat_dt_prop(node, "linux,cma-default", NULL); |
| struct cma *cma; |
| int err; |
| |
| if (size_cmdline != -1 && default_cma) { |
| pr_info("Reserved memory: bypass %s node, using cmdline CMA params instead\n", |
| rmem->name); |
| return -EBUSY; |
| } |
| |
| if (!of_get_flat_dt_prop(node, "reusable", NULL) || |
| of_get_flat_dt_prop(node, "no-map", NULL)) |
| return -EINVAL; |
| |
| if (!IS_ALIGNED(rmem->base | rmem->size, CMA_MIN_ALIGNMENT_BYTES)) { |
| 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 (default_cma) |
| dma_contiguous_default_area = 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 |