/*
 *  linux/arch/m68knommu/mm/init.c
 *
 *  Copyright (C) 1998  D. Jeff Dionne <jeff@lineo.ca>,
 *                      Kenneth Albanowski <kjahds@kjahds.com>,
 *  Copyright (C) 2000  Lineo, Inc.  (www.lineo.com) 
 *
 *  Based on:
 *
 *  linux/arch/m68k/mm/init.c
 *
 *  Copyright (C) 1995  Hamish Macdonald
 *
 *  JAN/1999 -- hacked to support ColdFire (gerg@snapgear.com)
 *  DEC/2000 -- linux 2.4 support <davidm@snapgear.com>
 */

#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/ptrace.h>
#include <linux/mman.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/init.h>
#include <linux/highmem.h>
#include <linux/pagemap.h>
#include <linux/bootmem.h>
#include <linux/slab.h>

#include <asm/setup.h>
#include <asm/segment.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/system.h>
#include <asm/machdep.h>

#undef DEBUG

extern void die_if_kernel(char *,struct pt_regs *,long);
extern void free_initmem(void);

/*
 * BAD_PAGE is the page that is used for page faults when linux
 * is out-of-memory. Older versions of linux just did a
 * do_exit(), but using this instead means there is less risk
 * for a process dying in kernel mode, possibly leaving a inode
 * unused etc..
 *
 * BAD_PAGETABLE is the accompanying page-table: it is initialized
 * to point to BAD_PAGE entries.
 *
 * ZERO_PAGE is a special page that is used for zero-initialized
 * data and COW.
 */
static unsigned long empty_bad_page_table;

static unsigned long empty_bad_page;

unsigned long empty_zero_page;

extern unsigned long memory_start;
extern unsigned long memory_end;

/*
 * paging_init() continues the virtual memory environment setup which
 * was begun by the code in arch/head.S.
 * The parameters are pointers to where to stick the starting and ending
 * addresses of available kernel virtual memory.
 */
void __init paging_init(void)
{
        /*
         * Make sure start_mem is page aligned, otherwise bootmem and
         * page_alloc get different views of the world.
         */
#ifdef DEBUG
        unsigned long start_mem = PAGE_ALIGN(memory_start);
#endif
        unsigned long end_mem   = memory_end & PAGE_MASK;

#ifdef DEBUG
        printk (KERN_DEBUG "start_mem is %#lx\nvirtual_end is %#lx\n",
                start_mem, end_mem);
#endif

        /*
         * Initialize the bad page table and bad page to point
         * to a couple of allocated pages.
         */
        empty_bad_page_table = (unsigned long)alloc_bootmem_pages(PAGE_SIZE);
        empty_bad_page = (unsigned long)alloc_bootmem_pages(PAGE_SIZE);
        empty_zero_page = (unsigned long)alloc_bootmem_pages(PAGE_SIZE);
        memset((void *)empty_zero_page, 0, PAGE_SIZE);

        /*
         * Set up SFC/DFC registers (user data space).
         */
        set_fs (USER_DS);

#ifdef DEBUG
        printk (KERN_DEBUG "before free_area_init\n");

        printk (KERN_DEBUG "free_area_init -> start_mem is %#lx\nvirtual_end is %#lx\n",
                start_mem, end_mem);
#endif

        {
                unsigned long zones_size[MAX_NR_ZONES] = {0, };

                zones_size[ZONE_DMA] = (end_mem - PAGE_OFFSET) >> PAGE_SHIFT;
                free_area_init(zones_size);
        }
}

void __init mem_init(void)
{
        int codek = 0, datak = 0, initk = 0;
        unsigned long tmp;
        extern char _etext, _stext, _sdata, _ebss, __init_begin, __init_end;
        extern unsigned int _ramend, _rambase;
        unsigned long len = _ramend - _rambase;
        unsigned long start_mem = memory_start; /* DAVIDM - these must start at end of kernel */
        unsigned long end_mem   = memory_end; /* DAVIDM - this must not include kernel stack at top */

        pr_debug("Mem_init: start=%lx, end=%lx\n", start_mem, end_mem);

        end_mem &= PAGE_MASK;
        high_memory = (void *) end_mem;

        start_mem = PAGE_ALIGN(start_mem);
        max_mapnr = num_physpages = (((unsigned long) high_memory) - PAGE_OFFSET) >> PAGE_SHIFT;

        /* this will put all memory onto the freelists */
        totalram_pages = free_all_bootmem();

        codek = (&_etext - &_stext) >> 10;
        datak = (&_ebss - &_sdata) >> 10;
        initk = (&__init_begin - &__init_end) >> 10;

        tmp = nr_free_pages() << PAGE_SHIFT;
        printk(KERN_INFO "Memory available: %luk/%luk RAM, (%dk kernel code, %dk data)\n",
               tmp >> 10,
               len >> 10,
               codek,
               datak
               );
}


#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", pages * (PAGE_SIZE / 1024));
}
#endif

void
free_initmem()
{
#ifdef CONFIG_RAMKERNEL
        unsigned long addr;
        extern char __init_begin, __init_end;
        /*
         * The following code should be cool even if these sections
         * are not page aligned.
         */
        addr = PAGE_ALIGN((unsigned long)(&__init_begin));
        /* next to check that the page we free is not a partial page */
        for (; addr + PAGE_SIZE < (unsigned long)(&__init_end); addr +=PAGE_SIZE) {
                ClearPageReserved(virt_to_page(addr));
                init_page_count(virt_to_page(addr));
                free_page(addr);
                totalram_pages++;
        }
        printk(KERN_NOTICE "Freeing unused kernel memory: %ldk freed (0x%x - 0x%x)\n",
                        (addr - PAGE_ALIGN((long) &__init_begin)) >> 10,
                        (int)(PAGE_ALIGN((unsigned long)(&__init_begin))),
                        (int)(addr - PAGE_SIZE));
#endif
}