/*
 * 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) 2000 by Ralf Baechle
 * Copyright (C) 2000 by Silicon Graphics, Inc.
 * Copyright (C) 2004 by Christoph Hellwig
 *
 * On SGI IP27 the ARC memory configuration data is completly bogus but
 * alternate easier to use mechanisms are available.
 */
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/mmzone.h>
#include <linux/swap.h>
#include <linux/bootmem.h>
#include <asm/page.h>
#include <asm/sections.h>

#include <asm/sn/arch.h>
#include <asm/sn/hub.h>
#include <asm/sn/klconfig.h>
#include <asm/sn/sn_private.h>


#define PFN_UP(x)               (((x) + PAGE_SIZE-1) >> PAGE_SHIFT)

#define SLOT_PFNSHIFT           (SLOT_SHIFT - PAGE_SHIFT)
#define PFN_NASIDSHFT           (NASID_SHFT - PAGE_SHIFT)

#define SLOT_IGNORED            0xffff

static short __initdata slot_lastfilled_cache[MAX_COMPACT_NODES];
static unsigned short __initdata slot_psize_cache[MAX_COMPACT_NODES][MAX_MEM_SLOTS];
static struct bootmem_data __initdata plat_node_bdata[MAX_COMPACT_NODES];

struct pglist_data *node_data[MAX_COMPACT_NODES];
struct hub_data *hub_data[MAX_COMPACT_NODES];

static pfn_t __init slot_getbasepfn(cnodeid_t cnode, int slot)
{
        nasid_t nasid = COMPACT_TO_NASID_NODEID(cnode);

        return ((pfn_t)nasid << PFN_NASIDSHFT) | (slot << SLOT_PFNSHIFT);
}

/*
 * Return the number of pages of memory provided by the given slot
 * on the specified node.
 */
static pfn_t __init slot_getsize(cnodeid_t node, int slot)
{
        return (pfn_t) slot_psize_cache[node][slot];
}

/*
 * Return highest slot filled
 */
static int __init node_getlastslot(cnodeid_t node)
{
        return (int) slot_lastfilled_cache[node];
}

/*
 * Return the pfn of the last free page of memory on a node.
 */
static pfn_t __init node_getmaxclick(cnodeid_t node)
{
        pfn_t   slot_psize;
        int     slot;

        /*
         * Start at the top slot. When we find a slot with memory in it,
         * that's the winner.
         */
        for (slot = (MAX_MEM_SLOTS - 1); slot >= 0; slot--) {
                if ((slot_psize = slot_getsize(node, slot))) {
                        if (slot_psize == SLOT_IGNORED)
                                continue;
                        /* Return the basepfn + the slot size, minus 1. */
                        return slot_getbasepfn(node, slot) + slot_psize - 1;
                }
        }

        /*
         * If there's no memory on the node, return 0. This is likely
         * to cause problems.
         */
        return 0;
}

static pfn_t __init slot_psize_compute(cnodeid_t node, int slot)
{
        nasid_t nasid;
        lboard_t *brd;
        klmembnk_t *banks;
        unsigned long size;

        nasid = COMPACT_TO_NASID_NODEID(node);
        /* Find the node board */
        brd = find_lboard((lboard_t *)KL_CONFIG_INFO(nasid), KLTYPE_IP27);
        if (!brd)
                return 0;

        /* Get the memory bank structure */
        banks = (klmembnk_t *) find_first_component(brd, KLSTRUCT_MEMBNK);
        if (!banks)
                return 0;

        /* Size in _Megabytes_ */
        size = (unsigned long)banks->membnk_bnksz[slot/4];

        /* hack for 128 dimm banks */
        if (size <= 128) {
                if (slot % 4 == 0) {
                        size <<= 20;            /* size in bytes */
                        return(size >> PAGE_SHIFT);
                } else
                        return 0;
        } else {
                size /= 4;
                size <<= 20;
                return size >> PAGE_SHIFT;
        }
}

static void __init szmem(void)
{
        pfn_t slot_psize, slot0sz = 0, nodebytes;       /* Hack to detect problem configs */
        int slot, ignore;
        cnodeid_t node;

        num_physpages = 0;

        for (node = 0; node < numnodes; node++) {
                ignore = nodebytes = 0;
                for (slot = 0; slot < MAX_MEM_SLOTS; slot++) {
                        slot_psize = slot_psize_compute(node, slot);
                        if (slot == 0)
                                slot0sz = slot_psize;
                        /*
                         * We need to refine the hack when we have replicated
                         * kernel text.
                         */
                        nodebytes += (1LL << SLOT_SHIFT);
                        if ((nodebytes >> PAGE_SHIFT) * (sizeof(struct page)) >
                                                (slot0sz << PAGE_SHIFT))
                                ignore = 1;
                        if (ignore && slot_psize) {
                                printk("Ignoring slot %d onwards on node %d\n",
                                                                slot, node);
                                slot_psize_cache[node][slot] = SLOT_IGNORED;
                                slot = MAX_MEM_SLOTS;
                                continue;
                        }
                        num_physpages += slot_psize;
                        slot_psize_cache[node][slot] =
                                        (unsigned short) slot_psize;
                        if (slot_psize)
                                slot_lastfilled_cache[node] = slot;
                }
        }
}

/*
 * Currently, the intranode memory hole support assumes that each slot
 * contains at least 32 MBytes of memory. We assume all bootmem data
 * fits on the first slot.
 */
void __init prom_meminit(void)
{
        cnodeid_t node;

        mlreset();
        szmem();

        for (node = 0; node < numnodes; node++) {
                pfn_t slot_firstpfn = slot_getbasepfn(node, 0);
                pfn_t slot_lastpfn = slot_firstpfn + slot_getsize(node, 0);
                pfn_t slot_freepfn = node_getfirstfree(node);
                unsigned long bootmap_size;

                /*
                 * Allocate the node data structures on the node first.
                 */
                node_data[node] = __va(slot_freepfn << PAGE_SHIFT);
                node_data[node]->bdata = &plat_node_bdata[node];

                hub_data[node] = (struct hub_data *)(node_data[node] + 1);

                cpus_clear(hub_data[node]->h_cpus);

                slot_freepfn += PFN_UP(sizeof(struct pglist_data) +
                                       sizeof(struct hub_data));
        
                bootmap_size = init_bootmem_node(NODE_DATA(node), slot_freepfn,
                                                slot_firstpfn, slot_lastpfn);
                free_bootmem_node(NODE_DATA(node), slot_firstpfn << PAGE_SHIFT,
                                (slot_lastpfn - slot_firstpfn) << PAGE_SHIFT);
                reserve_bootmem_node(NODE_DATA(node), slot_firstpfn << PAGE_SHIFT,
                  ((slot_freepfn - slot_firstpfn) << PAGE_SHIFT) + bootmap_size);
        }
}

unsigned long __init prom_free_prom_memory(void)
{
        /* We got nothing to free here ...  */
        return 0;
}

extern void pagetable_init(void);
extern unsigned long setup_zero_pages(void);

void __init paging_init(void)
{
        unsigned long zones_size[MAX_NR_ZONES] = {0, 0, 0};
        unsigned node;

        pagetable_init();

        for (node = 0; node < numnodes; node++) {
                pfn_t start_pfn = slot_getbasepfn(node, 0);
                pfn_t end_pfn = node_getmaxclick(node) + 1;

                zones_size[ZONE_DMA] = end_pfn - start_pfn;
                free_area_init_node(node, NODE_DATA(node), NULL,
                                zones_size, start_pfn, NULL);

                if (end_pfn > max_low_pfn)
                        max_low_pfn = end_pfn;
        }
}

void __init mem_init(void)
{
        unsigned long codesize, datasize, initsize, tmp;
        unsigned node;

        high_memory = (void *) __va(num_physpages << PAGE_SHIFT);

        for (node = 0; node < numnodes; node++) {
                unsigned slot, numslots;
                struct page *end, *p;
        
                /*
                 * This will free up the bootmem, ie, slot 0 memory.
                 */
                totalram_pages += free_all_bootmem_node(NODE_DATA(node));

                /*
                 * We need to manually do the other slots.
                 */
                numslots = node_getlastslot(node);
                for (slot = 1; slot <= numslots; slot++) {
                        p = NODE_DATA(node)->node_mem_map +
                                (slot_getbasepfn(node, slot) -
                                 slot_getbasepfn(node, 0));

                        /*
                         * Free valid memory in current slot.
                         */
                        for (end = p + slot_getsize(node, slot); p < end; p++) {
                                /* if (!page_is_ram(pgnr)) continue; */
                                /* commented out until page_is_ram works */
                                ClearPageReserved(p);
                                set_page_count(p, 1);
                                __free_page(p);
                                totalram_pages++;
                        }
                }
        }

        totalram_pages -= setup_zero_pages();   /* This comes from node 0 */

        codesize =  (unsigned long) &_etext - (unsigned long) &_text;
        datasize =  (unsigned long) &_edata - (unsigned long) &_etext;
        initsize =  (unsigned long) &__init_end - (unsigned long) &__init_begin;

        tmp = nr_free_pages();
        printk(KERN_INFO "Memory: %luk/%luk available (%ldk kernel code, "
               "%ldk reserved, %ldk data, %ldk init, %ldk highmem)\n",
               tmp << (PAGE_SHIFT-10),
               num_physpages << (PAGE_SHIFT-10),
               codesize >> 10,
               (num_physpages - tmp) << (PAGE_SHIFT-10),
               datasize >> 10,
               initsize >> 10,
               (unsigned long) (totalhigh_pages << (PAGE_SHIFT-10)));
}