445 строки
13 KiB
C
445 строки
13 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* Contiguous Memory Allocator for DMA mapping framework
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* Copyright (c) 2010-2011 by Samsung Electronics.
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* Written by:
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* Marek Szyprowski <m.szyprowski@samsung.com>
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* Michal Nazarewicz <mina86@mina86.com>
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*
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* Contiguous Memory Allocator
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*
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* The Contiguous Memory Allocator (CMA) makes it possible to
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* allocate big contiguous chunks of memory after the system has
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* booted.
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*
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* Why is it needed?
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*
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* Various devices on embedded systems have no scatter-getter and/or
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* IO map support and require contiguous blocks of memory to
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* operate. They include devices such as cameras, hardware video
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* coders, etc.
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*
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* Such devices often require big memory buffers (a full HD frame
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* is, for instance, more than 2 mega pixels large, i.e. more than 6
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* MB of memory), which makes mechanisms such as kmalloc() or
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* alloc_page() ineffective.
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*
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* At the same time, a solution where a big memory region is
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* reserved for a device is suboptimal since often more memory is
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* reserved then strictly required and, moreover, the memory is
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* inaccessible to page system even if device drivers don't use it.
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*
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* CMA tries to solve this issue by operating on memory regions
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* where only movable pages can be allocated from. This way, kernel
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* can use the memory for pagecache and when device driver requests
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* it, allocated pages can be migrated.
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*/
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#define pr_fmt(fmt) "cma: " fmt
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#ifdef CONFIG_CMA_DEBUG
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#ifndef DEBUG
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# define DEBUG
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#endif
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#endif
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#include <asm/page.h>
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#include <linux/memblock.h>
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#include <linux/err.h>
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#include <linux/sizes.h>
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#include <linux/dma-map-ops.h>
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#include <linux/cma.h>
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#ifdef CONFIG_CMA_SIZE_MBYTES
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#define CMA_SIZE_MBYTES CONFIG_CMA_SIZE_MBYTES
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#else
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#define CMA_SIZE_MBYTES 0
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#endif
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struct cma *dma_contiguous_default_area;
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/*
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* Default global CMA area size can be defined in kernel's .config.
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* This is useful mainly for distro maintainers to create a kernel
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* that works correctly for most supported systems.
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* The size can be set in bytes or as a percentage of the total memory
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* in the system.
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*
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* Users, who want to set the size of global CMA area for their system
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* should use cma= kernel parameter.
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*/
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static const phys_addr_t size_bytes __initconst =
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(phys_addr_t)CMA_SIZE_MBYTES * SZ_1M;
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static phys_addr_t size_cmdline __initdata = -1;
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static phys_addr_t base_cmdline __initdata;
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static phys_addr_t limit_cmdline __initdata;
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static int __init early_cma(char *p)
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{
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if (!p) {
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pr_err("Config string not provided\n");
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return -EINVAL;
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}
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size_cmdline = memparse(p, &p);
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if (*p != '@')
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return 0;
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base_cmdline = memparse(p + 1, &p);
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if (*p != '-') {
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limit_cmdline = base_cmdline + size_cmdline;
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return 0;
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}
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limit_cmdline = memparse(p + 1, &p);
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return 0;
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}
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early_param("cma", early_cma);
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#ifdef CONFIG_DMA_PERNUMA_CMA
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static struct cma *dma_contiguous_pernuma_area[MAX_NUMNODES];
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static phys_addr_t pernuma_size_bytes __initdata;
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static int __init early_cma_pernuma(char *p)
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{
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pernuma_size_bytes = memparse(p, &p);
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return 0;
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}
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early_param("cma_pernuma", early_cma_pernuma);
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#endif
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#ifdef CONFIG_CMA_SIZE_PERCENTAGE
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static phys_addr_t __init __maybe_unused cma_early_percent_memory(void)
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{
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unsigned long total_pages = PHYS_PFN(memblock_phys_mem_size());
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return (total_pages * CONFIG_CMA_SIZE_PERCENTAGE / 100) << PAGE_SHIFT;
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}
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#else
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static inline __maybe_unused phys_addr_t cma_early_percent_memory(void)
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{
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return 0;
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}
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#endif
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#ifdef CONFIG_DMA_PERNUMA_CMA
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void __init dma_pernuma_cma_reserve(void)
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{
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int nid;
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if (!pernuma_size_bytes)
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return;
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for_each_online_node(nid) {
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int ret;
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char name[CMA_MAX_NAME];
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struct cma **cma = &dma_contiguous_pernuma_area[nid];
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snprintf(name, sizeof(name), "pernuma%d", nid);
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ret = cma_declare_contiguous_nid(0, pernuma_size_bytes, 0, 0,
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0, false, name, cma, nid);
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if (ret) {
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pr_warn("%s: reservation failed: err %d, node %d", __func__,
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ret, nid);
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continue;
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}
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pr_debug("%s: reserved %llu MiB on node %d\n", __func__,
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(unsigned long long)pernuma_size_bytes / SZ_1M, nid);
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}
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}
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#endif
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/**
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* dma_contiguous_reserve() - reserve area(s) for contiguous memory handling
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* @limit: End address of the reserved memory (optional, 0 for any).
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*
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* This function reserves memory from early allocator. It should be
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* called by arch specific code once the early allocator (memblock or bootmem)
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* has been activated and all other subsystems have already allocated/reserved
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* memory.
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*/
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void __init dma_contiguous_reserve(phys_addr_t limit)
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{
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phys_addr_t selected_size = 0;
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phys_addr_t selected_base = 0;
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phys_addr_t selected_limit = limit;
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bool fixed = false;
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pr_debug("%s(limit %08lx)\n", __func__, (unsigned long)limit);
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if (size_cmdline != -1) {
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selected_size = size_cmdline;
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selected_base = base_cmdline;
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selected_limit = min_not_zero(limit_cmdline, limit);
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if (base_cmdline + size_cmdline == limit_cmdline)
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fixed = true;
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} else {
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#ifdef CONFIG_CMA_SIZE_SEL_MBYTES
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selected_size = size_bytes;
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#elif defined(CONFIG_CMA_SIZE_SEL_PERCENTAGE)
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selected_size = cma_early_percent_memory();
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#elif defined(CONFIG_CMA_SIZE_SEL_MIN)
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selected_size = min(size_bytes, cma_early_percent_memory());
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#elif defined(CONFIG_CMA_SIZE_SEL_MAX)
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selected_size = max(size_bytes, cma_early_percent_memory());
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#endif
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}
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if (selected_size && !dma_contiguous_default_area) {
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pr_debug("%s: reserving %ld MiB for global area\n", __func__,
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(unsigned long)selected_size / SZ_1M);
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dma_contiguous_reserve_area(selected_size, selected_base,
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selected_limit,
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&dma_contiguous_default_area,
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fixed);
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}
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}
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void __weak
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dma_contiguous_early_fixup(phys_addr_t base, unsigned long size)
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{
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}
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/**
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* dma_contiguous_reserve_area() - reserve custom contiguous area
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* @size: Size of the reserved area (in bytes),
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* @base: Base address of the reserved area optional, use 0 for any
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* @limit: End address of the reserved memory (optional, 0 for any).
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* @res_cma: Pointer to store the created cma region.
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* @fixed: hint about where to place the reserved area
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*
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* This function reserves memory from early allocator. It should be
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* called by arch specific code once the early allocator (memblock or bootmem)
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* has been activated and all other subsystems have already allocated/reserved
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* memory. This function allows to create custom reserved areas for specific
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* devices.
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*
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* If @fixed is true, reserve contiguous area at exactly @base. If false,
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* reserve in range from @base to @limit.
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*/
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int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
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phys_addr_t limit, struct cma **res_cma,
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bool fixed)
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{
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int ret;
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ret = cma_declare_contiguous(base, size, limit, 0, 0, fixed,
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"reserved", res_cma);
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if (ret)
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return ret;
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/* Architecture specific contiguous memory fixup. */
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dma_contiguous_early_fixup(cma_get_base(*res_cma),
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cma_get_size(*res_cma));
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return 0;
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}
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/**
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* dma_alloc_from_contiguous() - allocate pages from contiguous area
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* @dev: Pointer to device for which the allocation is performed.
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* @count: Requested number of pages.
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* @align: Requested alignment of pages (in PAGE_SIZE order).
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* @no_warn: Avoid printing message about failed allocation.
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*
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* This function allocates memory buffer for specified device. It uses
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* device specific contiguous memory area if available or the default
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* global one. Requires architecture specific dev_get_cma_area() helper
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* function.
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*/
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struct page *dma_alloc_from_contiguous(struct device *dev, size_t count,
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unsigned int align, bool no_warn)
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{
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if (align > CONFIG_CMA_ALIGNMENT)
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align = CONFIG_CMA_ALIGNMENT;
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return cma_alloc(dev_get_cma_area(dev), count, align, no_warn);
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}
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/**
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* dma_release_from_contiguous() - release allocated pages
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* @dev: Pointer to device for which the pages were allocated.
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* @pages: Allocated pages.
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* @count: Number of allocated pages.
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*
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* This function releases memory allocated by dma_alloc_from_contiguous().
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* It returns false when provided pages do not belong to contiguous area and
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* true otherwise.
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*/
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bool dma_release_from_contiguous(struct device *dev, struct page *pages,
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int count)
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{
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return cma_release(dev_get_cma_area(dev), pages, count);
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}
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static struct page *cma_alloc_aligned(struct cma *cma, size_t size, gfp_t gfp)
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{
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unsigned int align = min(get_order(size), CONFIG_CMA_ALIGNMENT);
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return cma_alloc(cma, size >> PAGE_SHIFT, align, gfp & __GFP_NOWARN);
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}
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/**
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* dma_alloc_contiguous() - allocate contiguous pages
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* @dev: Pointer to device for which the allocation is performed.
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* @size: Requested allocation size.
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* @gfp: Allocation flags.
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*
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* tries to use device specific contiguous memory area if available, or it
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* tries to use per-numa cma, if the allocation fails, it will fallback to
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* try default global one.
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*
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* Note that it bypass one-page size of allocations from the per-numa and
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* global area as the addresses within one page are always contiguous, so
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* there is no need to waste CMA pages for that kind; it also helps reduce
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* fragmentations.
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*/
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struct page *dma_alloc_contiguous(struct device *dev, size_t size, gfp_t gfp)
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{
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#ifdef CONFIG_DMA_PERNUMA_CMA
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int nid = dev_to_node(dev);
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#endif
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/* CMA can be used only in the context which permits sleeping */
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if (!gfpflags_allow_blocking(gfp))
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return NULL;
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if (dev->cma_area)
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return cma_alloc_aligned(dev->cma_area, size, gfp);
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if (size <= PAGE_SIZE)
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return NULL;
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#ifdef CONFIG_DMA_PERNUMA_CMA
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if (nid != NUMA_NO_NODE && !(gfp & (GFP_DMA | GFP_DMA32))) {
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struct cma *cma = dma_contiguous_pernuma_area[nid];
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struct page *page;
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if (cma) {
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page = cma_alloc_aligned(cma, size, gfp);
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if (page)
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return page;
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}
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}
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#endif
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if (!dma_contiguous_default_area)
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return NULL;
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return cma_alloc_aligned(dma_contiguous_default_area, size, gfp);
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}
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/**
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* dma_free_contiguous() - release allocated pages
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* @dev: Pointer to device for which the pages were allocated.
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* @page: Pointer to the allocated pages.
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* @size: Size of allocated pages.
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*
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* This function releases memory allocated by dma_alloc_contiguous(). As the
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* cma_release returns false when provided pages do not belong to contiguous
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* area and true otherwise, this function then does a fallback __free_pages()
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* upon a false-return.
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*/
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void dma_free_contiguous(struct device *dev, struct page *page, size_t size)
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{
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unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
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/* if dev has its own cma, free page from there */
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if (dev->cma_area) {
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if (cma_release(dev->cma_area, page, count))
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return;
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} else {
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/*
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* otherwise, page is from either per-numa cma or default cma
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*/
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#ifdef CONFIG_DMA_PERNUMA_CMA
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if (cma_release(dma_contiguous_pernuma_area[page_to_nid(page)],
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page, count))
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return;
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#endif
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if (cma_release(dma_contiguous_default_area, page, count))
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return;
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}
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/* not in any cma, free from buddy */
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__free_pages(page, get_order(size));
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}
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/*
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* Support for reserved memory regions defined in device tree
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*/
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#ifdef CONFIG_OF_RESERVED_MEM
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#include <linux/of.h>
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#include <linux/of_fdt.h>
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#include <linux/of_reserved_mem.h>
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#undef pr_fmt
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#define pr_fmt(fmt) fmt
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static int rmem_cma_device_init(struct reserved_mem *rmem, struct device *dev)
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{
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dev->cma_area = rmem->priv;
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return 0;
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}
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static void rmem_cma_device_release(struct reserved_mem *rmem,
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struct device *dev)
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{
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dev->cma_area = NULL;
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}
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static const struct reserved_mem_ops rmem_cma_ops = {
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.device_init = rmem_cma_device_init,
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.device_release = rmem_cma_device_release,
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};
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static int __init rmem_cma_setup(struct reserved_mem *rmem)
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{
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phys_addr_t align = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order);
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phys_addr_t mask = align - 1;
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unsigned long node = rmem->fdt_node;
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bool default_cma = of_get_flat_dt_prop(node, "linux,cma-default", NULL);
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struct cma *cma;
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int err;
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if (size_cmdline != -1 && default_cma) {
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pr_info("Reserved memory: bypass %s node, using cmdline CMA params instead\n",
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rmem->name);
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return -EBUSY;
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}
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if (!of_get_flat_dt_prop(node, "reusable", NULL) ||
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of_get_flat_dt_prop(node, "no-map", NULL))
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return -EINVAL;
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if ((rmem->base & mask) || (rmem->size & mask)) {
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pr_err("Reserved memory: incorrect alignment of CMA region\n");
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return -EINVAL;
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}
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err = cma_init_reserved_mem(rmem->base, rmem->size, 0, rmem->name, &cma);
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if (err) {
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pr_err("Reserved memory: unable to setup CMA region\n");
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return err;
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}
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/* Architecture specific contiguous memory fixup. */
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dma_contiguous_early_fixup(rmem->base, rmem->size);
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if (default_cma)
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dma_contiguous_default_area = cma;
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rmem->ops = &rmem_cma_ops;
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rmem->priv = cma;
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pr_info("Reserved memory: created CMA memory pool at %pa, size %ld MiB\n",
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&rmem->base, (unsigned long)rmem->size / SZ_1M);
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return 0;
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}
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RESERVEDMEM_OF_DECLARE(cma, "shared-dma-pool", rmem_cma_setup);
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#endif
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