// 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> #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 __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_PERNUMA_CMA static struct cma *dma_contiguous_pernuma_area[MAX_NUMNODES];static phys_addr_t pernuma_size_bytes __initdata; 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_PERNUMA_CMAvoid __init dma_pernuma_cma_reserve(void){	int nid; 	if (!pernuma_size_bytes)		return; 	for_each_online_node(nid) {		int ret;		char name[CMA_MAX_NAME];		struct cma **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);			continue;		} 		pr_debug("%s: reserved %llu MiB on node %d\n", __func__,			(unsigned long long)pernuma_size_bytes / SZ_1M, nid);	}}#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);	}} void __weakdma_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_PERNUMA_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_PERNUMA_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;		}	}#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_PERNUMA_CMA		if (cma_release(dma_contiguous_pernuma_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){	phys_addr_t align = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order);	phys_addr_t mask = align - 1;	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 ((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 (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