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init.c

/*
 * Copyright (C) 2007-2008 Michal Simek <monstr@monstr.eu>
 * Copyright (C) 2006 Atmark Techno, Inc.
 *
 * 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.
 */

#include <linux/bootmem.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/lmb.h>
#include <linux/mm.h> /* mem_init */
#include <linux/initrd.h>
#include <linux/pagemap.h>
#include <linux/pfn.h>
#include <linux/swap.h>

#include <asm/page.h>
#include <asm/mmu_context.h>
#include <asm/pgalloc.h>
#include <asm/sections.h>
#include <asm/tlb.h>

#ifndef CONFIG_MMU
unsigned int __page_offset;
EXPORT_SYMBOL(__page_offset);

#else
DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);

int mem_init_done;
static int init_bootmem_done;
#endif /* CONFIG_MMU */

char *klimit = _end;

/*
 * Initialize the bootmem system and give it all the memory we
 * have available.
 */
unsigned long memory_start;
unsigned long memory_end; /* due to mm/nommu.c */
unsigned long memory_size;

/*
 * paging_init() sets up the page tables - in fact we've already done this.
 */
static void __init paging_init(void)
{
      unsigned long zones_size[MAX_NR_ZONES];

      /* Clean every zones */
      memset(zones_size, 0, sizeof(zones_size));

      /*
       * old: we can DMA to/from any address.put all page into ZONE_DMA
       * We use only ZONE_NORMAL
       */
      zones_size[ZONE_NORMAL] = max_mapnr;

      free_area_init(zones_size);
}

void __init setup_memory(void)
{
      int i;
      unsigned long map_size;
#ifndef CONFIG_MMU
      u32 kernel_align_start, kernel_align_size;

      /* Find main memory where is the kernel */
      for (i = 0; i < lmb.memory.cnt; i++) {
            memory_start = (u32) lmb.memory.region[i].base;
            memory_end = (u32) lmb.memory.region[i].base
                        + (u32) lmb.memory.region[i].size;
            if ((memory_start <= (u32)_text) &&
                              ((u32)_text <= memory_end)) {
                  memory_size = memory_end - memory_start;
                  PAGE_OFFSET = memory_start;
                  printk(KERN_INFO "%s: Main mem: 0x%x-0x%x, "
                        "size 0x%08x\n", __func__, (u32) memory_start,
                              (u32) memory_end, (u32) memory_size);
                  break;
            }
      }

      if (!memory_start || !memory_end) {
            panic("%s: Missing memory setting 0x%08x-0x%08x\n",
                  __func__, (u32) memory_start, (u32) memory_end);
      }

      /* reservation of region where is the kernel */
      kernel_align_start = PAGE_DOWN((u32)_text);
      /* ALIGN can be remove because _end in vmlinux.lds.S is align */
      kernel_align_size = PAGE_UP((u32)klimit) - kernel_align_start;
      lmb_reserve(kernel_align_start, kernel_align_size);
      printk(KERN_INFO "%s: kernel addr=0x%08x-0x%08x size=0x%08x\n",
            __func__, kernel_align_start, kernel_align_start
                  + kernel_align_size, kernel_align_size);

#endif
      /*
       * Kernel:
       * start: base phys address of kernel - page align
       * end: base phys address of kernel - page align
       *
       * min_low_pfn - the first page (mm/bootmem.c - node_boot_start)
       * max_low_pfn
       * max_mapnr - the first unused page (mm/bootmem.c - node_low_pfn)
       * num_physpages - number of all pages
       */

      /* memory start is from the kernel end (aligned) to higher addr */
      min_low_pfn = memory_start >> PAGE_SHIFT; /* minimum for allocation */
      /* RAM is assumed contiguous */
      num_physpages = max_mapnr = memory_size >> PAGE_SHIFT;
      max_pfn = max_low_pfn = memory_end >> PAGE_SHIFT;

      printk(KERN_INFO "%s: max_mapnr: %#lx\n", __func__, max_mapnr);
      printk(KERN_INFO "%s: min_low_pfn: %#lx\n", __func__, min_low_pfn);
      printk(KERN_INFO "%s: max_low_pfn: %#lx\n", __func__, max_low_pfn);

      /*
       * Find an area to use for the bootmem bitmap.
       * We look for the first area which is at least
       * 128kB in length (128kB is enough for a bitmap
       * for 4GB of memory, using 4kB pages), plus 1 page
       * (in case the address isn't page-aligned).
       */
#ifndef CONFIG_MMU
      map_size = init_bootmem_node(NODE_DATA(0), PFN_UP(TOPHYS((u32)klimit)),
                              min_low_pfn, max_low_pfn);
#else
      map_size = init_bootmem_node(&contig_page_data,
            PFN_UP(TOPHYS((u32)klimit)), min_low_pfn, max_low_pfn);
#endif
      lmb_reserve(PFN_UP(TOPHYS((u32)klimit)) << PAGE_SHIFT, map_size);

      /* free bootmem is whole main memory */
      free_bootmem(memory_start, memory_size);

      /* reserve allocate blocks */
      for (i = 0; i < lmb.reserved.cnt; i++) {
            pr_debug("reserved %d - 0x%08x-0x%08x\n", i,
                  (u32) lmb.reserved.region[i].base,
                  (u32) lmb_size_bytes(&lmb.reserved, i));
            reserve_bootmem(lmb.reserved.region[i].base,
                  lmb_size_bytes(&lmb.reserved, i) - 1, BOOTMEM_DEFAULT);
      }
#ifdef CONFIG_MMU
      init_bootmem_done = 1;
#endif
      paging_init();
}

void free_init_pages(char *what, unsigned long begin, unsigned long end)
{
      unsigned long addr;

      for (addr = begin; addr < end; addr += PAGE_SIZE) {
            ClearPageReserved(virt_to_page(addr));
            init_page_count(virt_to_page(addr));
            memset((void *)addr, 0xcc, PAGE_SIZE);
            free_page(addr);
            totalram_pages++;
      }
      printk(KERN_INFO "Freeing %s: %ldk freed\n", what, (end - begin) >> 10);
}

#ifdef CONFIG_BLK_DEV_INITRD
void free_initrd_mem(unsigned long start, unsigned long end)
{
      int pages = 0;
      for (; start < end; start += PAGE_SIZE) {
            ClearPageReserved(virt_to_page(start));
            init_page_count(virt_to_page(start));
            free_page(start);
            totalram_pages++;
            pages++;
      }
      printk(KERN_NOTICE "Freeing initrd memory: %dk freed\n",
                              (int)(pages * (PAGE_SIZE / 1024)));
}
#endif

void free_initmem(void)
{
      free_init_pages("unused kernel memory",
                  (unsigned long)(&__init_begin),
                  (unsigned long)(&__init_end));
}

/* FIXME from arch/powerpc/mm/mem.c*/
void show_mem(void)
{
      printk(KERN_NOTICE "%s\n", __func__);
}

void __init mem_init(void)
{
      high_memory = (void *)__va(memory_end);
      /* this will put all memory onto the freelists */
      totalram_pages += free_all_bootmem();

      printk(KERN_INFO "Memory: %luk/%luk available\n",
             nr_free_pages() << (PAGE_SHIFT-10),
             num_physpages << (PAGE_SHIFT-10));
#ifdef CONFIG_MMU
      mem_init_done = 1;
#endif
}

#ifndef CONFIG_MMU
/* Check against bounds of physical memory */
int ___range_ok(unsigned long addr, unsigned long size)
{
      return ((addr < memory_start) ||
            ((addr + size) > memory_end));
}
EXPORT_SYMBOL(___range_ok);

#else
int page_is_ram(unsigned long pfn)
{
      return pfn < max_low_pfn;
}

/*
 * Check for command-line options that affect what MMU_init will do.
 */
static void mm_cmdline_setup(void)
{
      unsigned long maxmem = 0;
      char *p = cmd_line;

      /* Look for mem= option on command line */
      p = strstr(cmd_line, "mem=");
      if (p) {
            p += 4;
            maxmem = memparse(p, &p);
            if (maxmem && memory_size > maxmem) {
                  memory_size = maxmem;
                  memory_end = memory_start + memory_size;
                  lmb.memory.region[0].size = memory_size;
            }
      }
}

/*
 * MMU_init_hw does the chip-specific initialization of the MMU hardware.
 */
static void __init mmu_init_hw(void)
{
      /*
       * The Zone Protection Register (ZPR) defines how protection will
       * be applied to every page which is a member of a given zone. At
       * present, we utilize only two of the zones.
       * The zone index bits (of ZSEL) in the PTE are used for software
       * indicators, except the LSB.  For user access, zone 1 is used,
       * for kernel access, zone 0 is used.  We set all but zone 1
       * to zero, allowing only kernel access as indicated in the PTE.
       * For zone 1, we set a 01 binary (a value of 10 will not work)
       * to allow user access as indicated in the PTE.  This also allows
       * kernel access as indicated in the PTE.
       */
      __asm__ __volatile__ ("ori r11, r0, 0x10000000;" \
                  "mts rzpr, r11;"
                  : : : "r11");
}

/*
 * MMU_init sets up the basic memory mappings for the kernel,
 * including both RAM and possibly some I/O regions,
 * and sets up the page tables and the MMU hardware ready to go.
 */

/* called from head.S */
asmlinkage void __init mmu_init(void)
{
      unsigned int kstart, ksize;

      if (!lmb.reserved.cnt) {
            printk(KERN_EMERG "Error memory count\n");
            machine_restart(NULL);
      }

      if ((u32) lmb.memory.region[0].size < 0x1000000) {
            printk(KERN_EMERG "Memory must be greater than 16MB\n");
            machine_restart(NULL);
      }
      /* Find main memory where the kernel is */
      memory_start = (u32) lmb.memory.region[0].base;
      memory_end = (u32) lmb.memory.region[0].base +
                        (u32) lmb.memory.region[0].size;
      memory_size = memory_end - memory_start;

      mm_cmdline_setup(); /* FIXME parse args from command line - not used */

      /*
       * Map out the kernel text/data/bss from the available physical
       * memory.
       */
      kstart = __pa(CONFIG_KERNEL_START); /* kernel start */
      /* kernel size */
      ksize = PAGE_ALIGN(((u32)_end - (u32)CONFIG_KERNEL_START));
      lmb_reserve(kstart, ksize);

#if defined(CONFIG_BLK_DEV_INITRD)
      /* Remove the init RAM disk from the available memory. */
/*    if (initrd_start) {
            mem_pieces_remove(&phys_avail, __pa(initrd_start),
                          initrd_end - initrd_start, 1);
      }*/
#endif /* CONFIG_BLK_DEV_INITRD */

      /* Initialize the MMU hardware */
      mmu_init_hw();

      /* Map in all of RAM starting at CONFIG_KERNEL_START */
      mapin_ram();

#ifdef HIGHMEM_START_BOOL
      ioremap_base = HIGHMEM_START;
#else
      ioremap_base = 0xfe000000UL;  /* for now, could be 0xfffff000 */
#endif /* CONFIG_HIGHMEM */
      ioremap_bot = ioremap_base;

      /* Initialize the context management stuff */
      mmu_context_init();
}

/* This is only called until mem_init is done. */
void __init *early_get_page(void)
{
      void *p;
      if (init_bootmem_done) {
            p = alloc_bootmem_pages(PAGE_SIZE);
      } else {
            /*
             * Mem start + 32MB -> here is limit
             * because of mem mapping from head.S
             */
            p = __va(lmb_alloc_base(PAGE_SIZE, PAGE_SIZE,
                              memory_start + 0x2000000));
      }
      return p;
}
#endif /* CONFIG_MMU */

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