/*
 *  linux/arch/arm26/mm/init.c
 *
 *  Copyright (C) 1995-2002 Russell King
 *
 * 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/config.h>
#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/smp.h>
#include <linux/init.h>
#include <linux/initrd.h>
#include <linux/bootmem.h>
#include <linux/blkdev.h>

#include <asm/segment.h>
#include <asm/mach-types.h>
#include <asm/dma.h>
#include <asm/hardware.h>
#include <asm/setup.h>
#include <asm/tlb.h>

#include <asm/map.h>


#define TABLE_SIZE      PTRS_PER_PTE * sizeof(pte_t))

struct mmu_gather mmu_gathers[NR_CPUS];

extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
extern char _stext, _text, _etext, _end, __init_begin, __init_end;
#ifdef CONFIG_XIP_KERNEL
extern char _endtext, _sdata;
#endif
extern unsigned long phys_initrd_start;
extern unsigned long phys_initrd_size;

/*
 * The sole use of this is to pass memory configuration
 * data from paging_init to mem_init.
 */
static struct meminfo meminfo __initdata = { 0, };

/*
 * empty_zero_page is a special page that is used for
 * zero-initialized data and COW.
 */
struct page *empty_zero_page;

void show_mem(void)
{
        int free = 0, total = 0, reserved = 0;
        int shared = 0, cached = 0, slab = 0;
        struct page *page, *end;

        printk("Mem-info:\n");
        show_free_areas();
        printk("Free swap:       %6ldkB\n", nr_swap_pages<<(PAGE_SHIFT-10));


        page = NODE_MEM_MAP(0);
        end  = page + NODE_DATA(0)->node_spanned_pages;

        do {
                total++;
                if (PageReserved(page))
                        reserved++;
                else if (PageSwapCache(page))
                        cached++;
                else if (PageSlab(page))
                        slab++;
                else if (!page_count(page))
                        free++;
                else
                        shared += page_count(page) - 1;
                page++;
        } while (page < end);

        printk("%d pages of RAM\n", total);
        printk("%d free pages\n", free);
        printk("%d reserved pages\n", reserved);
        printk("%d slab pages\n", slab);
        printk("%d pages shared\n", shared);
        printk("%d pages swap cached\n", cached);
}

struct node_info {
        unsigned int start;
        unsigned int end;
        int bootmap_pages;
};

#define PFN_DOWN(x)     ((x) >> PAGE_SHIFT)
#define PFN_UP(x)       (PAGE_ALIGN(x) >> PAGE_SHIFT)
#define PFN_SIZE(x)     ((x) >> PAGE_SHIFT)
#define PFN_RANGE(s,e)  PFN_SIZE(PAGE_ALIGN((unsigned long)(e)) - \
                                (((unsigned long)(s)) & PAGE_MASK))

/*
 * FIXME: We really want to avoid allocating the bootmap bitmap
 * over the top of the initrd.  Hopefully, this is located towards
 * the start of a bank, so if we allocate the bootmap bitmap at
 * the end, we won't clash.
 */
static unsigned int __init
find_bootmap_pfn(struct meminfo *mi, unsigned int bootmap_pages)
{
        unsigned int start_pfn, bootmap_pfn;
        unsigned int start, end;

        start_pfn   = PFN_UP((unsigned long)&_end);
        bootmap_pfn = 0;

        /* ARM26 machines only have one node */
        if (mi->bank->node != 0)
                BUG();

        start = PFN_UP(mi->bank->start);
        end   = PFN_DOWN(mi->bank->size + mi->bank->start);

        if (start < start_pfn)
                start = start_pfn;

        if (end <= start)
                BUG();

        if (end - start >= bootmap_pages) 
                bootmap_pfn = start;
        else
                BUG();

        return bootmap_pfn;
}

/*
 * Scan the memory info structure and pull out:
 *  - the end of memory
 *  - the number of nodes
 *  - the pfn range of each node
 *  - the number of bootmem bitmap pages
 */
static void __init
find_memend_and_nodes(struct meminfo *mi, struct node_info *np)
{
        unsigned int memend_pfn = 0;

        nodes_clear(node_online_map);
        node_set_online(0);

        np->bootmap_pages = 0;

        if (mi->bank->size == 0) {
                BUG();
        }

        /*
         * Get the start and end pfns for this bank
         */
        np->start = PFN_UP(mi->bank->start);
        np->end   = PFN_DOWN(mi->bank->start + mi->bank->size);

        if (memend_pfn < np->end)
                memend_pfn = np->end;

        /*
         * Calculate the number of pages we require to
         * store the bootmem bitmaps.
         */
        np->bootmap_pages = bootmem_bootmap_pages(np->end - np->start);

        /*
         * This doesn't seem to be used by the Linux memory
         * manager any more.  If we can get rid of it, we
         * also get rid of some of the stuff above as well.
         */
        max_low_pfn = memend_pfn - PFN_DOWN(PHYS_OFFSET);
        max_pfn = memend_pfn - PFN_DOWN(PHYS_OFFSET);
        mi->end = memend_pfn << PAGE_SHIFT;

}

/*
 * Initialise the bootmem allocator for all nodes.  This is called
 * early during the architecture specific initialisation.
 */
void __init bootmem_init(struct meminfo *mi)
{
        struct node_info node_info;
        unsigned int bootmap_pfn;
        pg_data_t *pgdat = NODE_DATA(0);

        find_memend_and_nodes(mi, &node_info);

        bootmap_pfn   = find_bootmap_pfn(mi, node_info.bootmap_pages);

        /*
         * Note that node 0 must always have some pages.
         */
        if (node_info.end == 0)
                BUG();

        /*
         * Initialise the bootmem allocator.
         */
        init_bootmem_node(pgdat, bootmap_pfn, node_info.start, node_info.end);

        /*
         * Register all available RAM in this node with the bootmem allocator. 
         */
        free_bootmem_node(pgdat, mi->bank->start, mi->bank->size);

        /*
         * Register the kernel text and data with bootmem.
         * Note: with XIP we dont register .text since
         * its in ROM.
         */
#ifdef CONFIG_XIP_KERNEL
        reserve_bootmem_node(pgdat, __pa(&_sdata), &_end - &_sdata);
#else
        reserve_bootmem_node(pgdat, __pa(&_stext), &_end - &_stext);
#endif

        /*
         * And don't forget to reserve the allocator bitmap,
         * which will be freed later.
         */
        reserve_bootmem_node(pgdat, bootmap_pfn << PAGE_SHIFT,
                             node_info.bootmap_pages << PAGE_SHIFT);

        /*
         * These should likewise go elsewhere.  They pre-reserve
         * the screen memory region at the start of main system
         * memory. FIXME - screen RAM is not 512K!
         */
        reserve_bootmem_node(pgdat, 0x02000000, 0x00080000);

#ifdef CONFIG_BLK_DEV_INITRD
        initrd_start = phys_initrd_start;
        initrd_end = initrd_start + phys_initrd_size;

        /* Achimedes machines only have one node, so initrd is in node 0 */
#ifdef CONFIG_XIP_KERNEL
        /* Only reserve initrd space if it is in RAM */
        if(initrd_start && initrd_start < 0x03000000){
#else
        if(initrd_start){
#endif
                reserve_bootmem_node(pgdat, __pa(initrd_start),
                                             initrd_end - initrd_start);
        }
#endif   /* CONFIG_BLK_DEV_INITRD */


}

/*
 * paging_init() sets up the page tables, initialises the zone memory
 * maps, and sets up the zero page, bad page and bad page tables.
 */
void __init paging_init(struct meminfo *mi)
{
        void *zero_page;
        unsigned long zone_size[MAX_NR_ZONES];
        unsigned long zhole_size[MAX_NR_ZONES];
        struct bootmem_data *bdata;
        pg_data_t *pgdat;
        int i;

        memcpy(&meminfo, mi, sizeof(meminfo));

        /*
         * allocate the zero page.  Note that we count on this going ok.
         */
        zero_page = alloc_bootmem_low_pages(PAGE_SIZE);

        /*
         * initialise the page tables.
         */
        memtable_init(mi);
        flush_tlb_all();

        /*
         * initialise the zones in node 0 (archimedes have only 1 node)
         */

        for (i = 0; i < MAX_NR_ZONES; i++) {
                zone_size[i]  = 0;
                zhole_size[i] = 0;
        }

        pgdat = NODE_DATA(0);
        bdata = pgdat->bdata;
        zone_size[0] = bdata->node_low_pfn -
                        (bdata->node_boot_start >> PAGE_SHIFT);
        if (!zone_size[0])
                BUG();
        pgdat->node_mem_map = NULL;
        free_area_init_node(0, pgdat, zone_size,
                        bdata->node_boot_start >> PAGE_SHIFT, zhole_size);

        mem_map = NODE_DATA(0)->node_mem_map;

        /*
         * finish off the bad pages once
         * the mem_map is initialised
         */
        memzero(zero_page, PAGE_SIZE);
        empty_zero_page = virt_to_page(zero_page);
}

static inline void free_area(unsigned long addr, unsigned long end, char *s)
{
        unsigned int size = (end - addr) >> 10;

        for (; addr < end; addr += PAGE_SIZE) {
                struct page *page = virt_to_page(addr);
                ClearPageReserved(page);
                set_page_count(page, 1);
                free_page(addr);
                totalram_pages++;
        }

        if (size && s)
                printk(KERN_INFO "Freeing %s memory: %dK\n", s, size);
}

/*
 * mem_init() marks the free areas in the mem_map and tells us how much
 * memory is free.  This is done after various parts of the system have
 * claimed their memory after the kernel image.
 */
void __init mem_init(void)
{
        unsigned int codepages, datapages, initpages;
        pg_data_t *pgdat = NODE_DATA(0);
        extern int sysctl_overcommit_memory;


        /* Note: data pages includes BSS */
#ifdef CONFIG_XIP_KERNEL
        codepages = &_endtext - &_text;
        datapages = &_end - &_sdata;
#else
        codepages = &_etext - &_text;
        datapages = &_end - &_etext;
#endif
        initpages = &__init_end - &__init_begin;

        high_memory = (void *)__va(meminfo.end);
        max_mapnr   = virt_to_page(high_memory) - mem_map;

        /* this will put all unused low memory onto the freelists */
        if (pgdat->node_spanned_pages != 0)
                totalram_pages += free_all_bootmem_node(pgdat);

        num_physpages = meminfo.bank[0].size >> PAGE_SHIFT;

        printk(KERN_INFO "Memory: %luMB total\n", num_physpages >> (20 - PAGE_SHIFT));
        printk(KERN_NOTICE "Memory: %luKB available (%dK code, "
                "%dK data, %dK init)\n",
                (unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
                codepages >> 10, datapages >> 10, initpages >> 10);

        /*
         * Turn on overcommit on tiny machines
         */
        if (PAGE_SIZE >= 16384 && num_physpages <= 128) {
                sysctl_overcommit_memory = OVERCOMMIT_ALWAYS;
                printk("Turning on overcommit\n");
        }
}

void free_initmem(void){
#ifndef CONFIG_XIP_KERNEL
        free_area((unsigned long)(&__init_begin),
                  (unsigned long)(&__init_end),
                  "init");
#endif
}

#ifdef CONFIG_BLK_DEV_INITRD

static int keep_initrd;

void free_initrd_mem(unsigned long start, unsigned long end)
{
#ifdef CONFIG_XIP_KERNEL
        /* Only bin initrd if it is in RAM... */
        if(!keep_initrd && start < 0x03000000)
#else
        if (!keep_initrd)
#endif
                free_area(start, end, "initrd");
}

static int __init keepinitrd_setup(char *__unused)
{
        keep_initrd = 1;
        return 1;
}

__setup("keepinitrd", keepinitrd_setup);
#endif