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kernel/linux-imx6_3.14.28/arch/arc/mm/init.c 3.57 KB
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  /*
   * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   */
  
  #include <linux/kernel.h>
  #include <linux/mm.h>
  #include <linux/bootmem.h>
  #include <linux/memblock.h>
  #include <linux/swap.h>
  #include <linux/module.h>
  #include <asm/page.h>
  #include <asm/pgalloc.h>
  #include <asm/sections.h>
  #include <asm/arcregs.h>
  
  pgd_t swapper_pg_dir[PTRS_PER_PGD] __aligned(PAGE_SIZE);
  char empty_zero_page[PAGE_SIZE] __aligned(PAGE_SIZE);
  EXPORT_SYMBOL(empty_zero_page);
  
  /* Default tot mem from .config */
  static unsigned long arc_mem_sz = 0x20000000;  /* some default */
  
  /* User can over-ride above with "mem=nnn[KkMm]" in cmdline */
  static int __init setup_mem_sz(char *str)
  {
  	arc_mem_sz = memparse(str, NULL) & PAGE_MASK;
  
  	/* early console might not be setup yet - it will show up later */
  	pr_info("\"mem=%s\": mem sz set to %ldM
  ", str, TO_MB(arc_mem_sz));
  
  	return 0;
  }
  early_param("mem", setup_mem_sz);
  
  void __init early_init_dt_add_memory_arch(u64 base, u64 size)
  {
  	arc_mem_sz = size & PAGE_MASK;
  	pr_info("Memory size set via devicetree %ldM
  ", TO_MB(arc_mem_sz));
  }
  
  /*
   * First memory setup routine called from setup_arch()
   * 1. setup swapper's mm @init_mm
   * 2. Count the pages we have and setup bootmem allocator
   * 3. zone setup
   */
  void __init setup_arch_memory(void)
  {
  	unsigned long zones_size[MAX_NR_ZONES] = { 0, 0 };
  	unsigned long end_mem = CONFIG_LINUX_LINK_BASE + arc_mem_sz;
  
  	init_mm.start_code = (unsigned long)_text;
  	init_mm.end_code = (unsigned long)_etext;
  	init_mm.end_data = (unsigned long)_edata;
  	init_mm.brk = (unsigned long)_end;
  
  	/*
  	 * We do it here, so that memory is correctly instantiated
  	 * even if "mem=xxx" cmline over-ride is given and/or
  	 * DT has memory node. Each causes an update to @arc_mem_sz
  	 * and we finally add memory one here
  	 */
  	memblock_add(CONFIG_LINUX_LINK_BASE, arc_mem_sz);
  
  	/*------------- externs in mm need setting up ---------------*/
  
  	/* first page of system - kernel .vector starts here */
  	min_low_pfn = PFN_DOWN(CONFIG_LINUX_LINK_BASE);
  
  	/* Last usable page of low mem (no HIGHMEM yet for ARC port) */
  	max_low_pfn = max_pfn = PFN_DOWN(end_mem);
  
  	max_mapnr = max_low_pfn - min_low_pfn;
  
  	/*------------- reserve kernel image -----------------------*/
  	memblock_reserve(CONFIG_LINUX_LINK_BASE,
  			 __pa(_end) - CONFIG_LINUX_LINK_BASE);
  
  	memblock_dump_all();
  
  	/*-------------- node setup --------------------------------*/
  	memset(zones_size, 0, sizeof(zones_size));
  	zones_size[ZONE_NORMAL] = max_low_pfn - min_low_pfn;
  
  	/*
  	 * We can't use the helper free_area_init(zones[]) because it uses
  	 * PAGE_OFFSET to compute the @min_low_pfn which would be wrong
  	 * when our kernel doesn't start at PAGE_OFFSET, i.e.
  	 * PAGE_OFFSET != CONFIG_LINUX_LINK_BASE
  	 */
  	free_area_init_node(0,			/* node-id */
  			    zones_size,		/* num pages per zone */
  			    min_low_pfn,	/* first pfn of node */
  			    NULL);		/* NO holes */
  }
  
  /*
   * mem_init - initializes memory
   *
   * Frees up bootmem
   * Calculates and displays memory available/used
   */
  void __init mem_init(void)
  {
  	high_memory = (void *)(CONFIG_LINUX_LINK_BASE + arc_mem_sz);
  	free_all_bootmem();
  	mem_init_print_info(NULL);
  }
  
  /*
   * free_initmem: Free all the __init memory.
   */
  void __init_refok free_initmem(void)
  {
  	free_initmem_default(-1);
  }
  
  #ifdef CONFIG_BLK_DEV_INITRD
  void __init free_initrd_mem(unsigned long start, unsigned long end)
  {
  	free_reserved_area((void *)start, (void *)end, -1, "initrd");
  }
  #endif