214 lines
6.3 KiB
C
214 lines
6.3 KiB
C
/*
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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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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License or (at your optional) any later version of the license.
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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 <asm/dma-contiguous.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-contiguous.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 = CMA_SIZE_MBYTES * SZ_1M;
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static phys_addr_t size_cmdline = -1;
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static phys_addr_t base_cmdline;
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static phys_addr_t limit_cmdline;
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static int __init early_cma(char *p)
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{
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pr_debug("%s(%s)\n", __func__, p);
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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_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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struct memblock_region *reg;
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unsigned long total_pages = 0;
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/*
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* We cannot use memblock_phys_mem_size() here, because
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* memblock_analyze() has not been called yet.
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*/
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for_each_memblock(memory, reg)
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total_pages += memblock_region_memory_end_pfn(reg) -
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memblock_region_memory_base_pfn(reg);
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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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/**
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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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/**
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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, 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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*
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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, int count,
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unsigned int align)
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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);
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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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