text: /*
   * arch/xtensa/mm/init.c
   *
   * Derived from MIPS, PPC.
   *
   * This file is subject to the terms and conditions of the GNU General Public
   * License.  See the file "COPYING" in the main directory of this archive
   * for more details.
   *
   * Copyright (C) 2001 - 2005 Tensilica Inc.
   *
   * Chris Zankel	<chris@zankel.net>
   * Joe Taylor	<joe@tensilica.com, joetylr@yahoo.com>
   * Marc Gauthier
   * Kevin Chea
   */
  
  #include <linux/kernel.h>
  #include <linux/errno.h>
  #include <linux/bootmem.h>
  #include <linux/swap.h>
  #include <linux/mman.h>
  #include <linux/nodemask.h>
  #include <linux/mm.h>
  #include <linux/slab.h>
  
  #include <asm/bootparam.h>
  #include <asm/page.h>
  
  /* References to section boundaries */
  
  extern char _ftext, _etext, _fdata, _edata, _rodata_end;
  extern char __init_begin, __init_end;
  
  /*
   * mem_reserve(start, end, must_exist)
   *
   * Reserve some memory from the memory pool.
   *
   * Parameters:
   *  start	Start of region,
   *  end		End of region,
   *  must_exist	Must exist in memory pool.
   *
   * Returns:
   *  0 (memory area couldn't be mapped)
   * -1 (success)
   */
  
  int __init mem_reserve(unsigned long start, unsigned long end, int must_exist)
  {
  	int i;
  
  	if (start == end)
  		return 0;
  
  	start = start & PAGE_MASK;
  	end = PAGE_ALIGN(end);
  
  	for (i = 0; i < sysmem.nr_banks; i++)
  		if (start < sysmem.bank[i].end
  		    && end >= sysmem.bank[i].start)
  			break;
  
  	if (i == sysmem.nr_banks) {
  		if (must_exist)
  			printk (KERN_WARNING "mem_reserve: [0x%0lx, 0x%0lx) "
  				"not in any region!\n", start, end);
  		return 0;
  	}
  
  	if (start > sysmem.bank[i].start) {
  		if (end < sysmem.bank[i].end) {
  			/* split entry */
  			if (sysmem.nr_banks >= SYSMEM_BANKS_MAX)
  				panic("meminfo overflow\n");
  			sysmem.bank[sysmem.nr_banks].start = end;
  			sysmem.bank[sysmem.nr_banks].end = sysmem.bank[i].end;
  			sysmem.nr_banks++;
  		}
  		sysmem.bank[i].end = start;
  	} else {
  		if (end < sysmem.bank[i].end)
  			sysmem.bank[i].start = end;
  		else {
  			/* remove entry */
  			sysmem.nr_banks--;
  			sysmem.bank[i].start = sysmem.bank[sysmem.nr_banks].start;
  			sysmem.bank[i].end   = sysmem.bank[sysmem.nr_banks].end;
  		}
  	}
  	return -1;
  }
  
  
  /*
   * Initialize the bootmem system and give it all the memory we have available.
   */
  
  void __init bootmem_init(void)
  {
  	unsigned long pfn;
  	unsigned long bootmap_start, bootmap_size;
  	int i;
  
  	max_low_pfn = max_pfn = 0;
  	min_low_pfn = ~0;
  
  	for (i=0; i < sysmem.nr_banks; i++) {
  		pfn = PAGE_ALIGN(sysmem.bank[i].start) >> PAGE_SHIFT;
  		if (pfn < min_low_pfn)
  			min_low_pfn = pfn;
  		pfn = PAGE_ALIGN(sysmem.bank[i].end - 1) >> PAGE_SHIFT;
  		if (pfn > max_pfn)
  			max_pfn = pfn;
  	}
  
  	if (min_low_pfn > max_pfn)
  		panic("No memory found!\n");
  
  	max_low_pfn = max_pfn < MAX_MEM_PFN >> PAGE_SHIFT ?
  		max_pfn : MAX_MEM_PFN >> PAGE_SHIFT;
  
  	/* Find an area to use for the bootmem bitmap. */
  
  	bootmap_size = bootmem_bootmap_pages(max_low_pfn - min_low_pfn);
  	bootmap_size <<= PAGE_SHIFT;
  	bootmap_start = ~0;
  
  	for (i=0; i<sysmem.nr_banks; i++)
  		if (sysmem.bank[i].end - sysmem.bank[i].start >= bootmap_size) {
  			bootmap_start = sysmem.bank[i].start;
  			break;
  		}
  
  	if (bootmap_start == ~0UL)
  		panic("Cannot find %ld bytes for bootmap\n", bootmap_size);
  
  	/* Reserve the bootmem bitmap area */
  
  	mem_reserve(bootmap_start, bootmap_start + bootmap_size, 1);
  	bootmap_size = init_bootmem_node(NODE_DATA(0),
  					 bootmap_start >> PAGE_SHIFT,
  					 min_low_pfn,
  					 max_low_pfn);
  
  	/* Add all remaining memory pieces into the bootmem map */
  
  	for (i=0; i<sysmem.nr_banks; i++)
  		free_bootmem(sysmem.bank[i].start,
  			     sysmem.bank[i].end - sysmem.bank[i].start);
  
  }
  
  
  void __init zones_init(void)
  {
  	unsigned long zones_size[MAX_NR_ZONES];
  	int i;
  
  	/* All pages are DMA-able, so we put them all in the DMA zone. */
  
  	zones_size[ZONE_DMA] = max_low_pfn - ARCH_PFN_OFFSET;
  	for (i = 1; i < MAX_NR_ZONES; i++)
  		zones_size[i] = 0;
  
  #ifdef CONFIG_HIGHMEM
  	zones_size[ZONE_HIGHMEM] = max_pfn - max_low_pfn;
  #endif
  
  	free_area_init_node(0, zones_size, ARCH_PFN_OFFSET, NULL);
  }
  
  /*
   * Initialize memory pages.
   */
  
  void __init mem_init(void)
  {
  	unsigned long codesize, reservedpages, datasize, initsize;
  	unsigned long highmemsize, tmp, ram;
  
  	max_mapnr = num_physpages = max_low_pfn - ARCH_PFN_OFFSET;
  	high_memory = (void *) __va(max_low_pfn << PAGE_SHIFT);
  	highmemsize = 0;
  
  #ifdef CONFIG_HIGHMEM
  #error HIGHGMEM not implemented in init.c
  #endif
  
  	totalram_pages += free_all_bootmem();
  
  	reservedpages = ram = 0;
  	for (tmp = 0; tmp < max_mapnr; tmp++) {
  		ram++;
  		if (PageReserved(mem_map+tmp))
  			reservedpages++;
  	}
  
  	codesize =  (unsigned long) &_etext - (unsigned long) &_ftext;
  	datasize =  (unsigned long) &_edata - (unsigned long) &_fdata;
  	initsize =  (unsigned long) &__init_end - (unsigned long) &__init_begin;
  
  	printk("Memory: %luk/%luk available (%ldk kernel code, %ldk reserved, "
  	       "%ldk data, %ldk init %ldk highmem)\n",
  	       nr_free_pages() << (PAGE_SHIFT-10),
  	       ram << (PAGE_SHIFT-10),
  	       codesize >> 10,
  	       reservedpages << (PAGE_SHIFT-10),
  	       datasize >> 10,
  	       initsize >> 10,
  	       highmemsize >> 10);
  }
  
  void
  free_reserved_mem(void *start, void *end)
  {
  	for (; start < end; start += PAGE_SIZE) {
  		ClearPageReserved(virt_to_page(start));
  		init_page_count(virt_to_page(start));
  		free_page((unsigned long)start);
  		totalram_pages++;
  	}
  }
  
  #ifdef CONFIG_BLK_DEV_INITRD
  extern int initrd_is_mapped;
  
  void free_initrd_mem(unsigned long start, unsigned long end)
  {
  	if (initrd_is_mapped) {
  		free_reserved_mem((void*)start, (void*)end);
  		printk ("Freeing initrd memory: %ldk freed\n",(end-start)>>10);
  	}
  }
  #endif
  
  void free_initmem(void)
  {
  	free_reserved_mem(&__init_begin, &__init_end);
  	printk("Freeing unused kernel memory: %dk freed\n",
  	       (&__init_end - &__init_begin) >> 10);
  }
  