/*
 *    Copyright (c) 1996 Paul Mackerras <paulus@cs.anu.edu.au>
 *      Changes to accomodate Power Macintoshes.
 *    Cort Dougan <cort@cs.nmt.edu>
 *      Rewrites.
 *    Grant Erickson <grant@lcse.umn.edu>
 *      General rework and split from mm/init.c.
 *
 *    Module name: mem_pieces.c
 *
 *    Description:
 *      Routines and data structures for manipulating and representing
 *      phyiscal memory extents (i.e. address/length pairs).
 *
 */

#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/stddef.h>
#include <linux/blk.h>
#include <linux/init.h>

#include "mem_pieces.h"

extern struct mem_pieces phys_avail;

static void mem_pieces_print(struct mem_pieces *);

/*
 * Scan a region for a piece of a given size with the required alignment.
 */
void __init *
mem_pieces_find(unsigned int size, unsigned int align)
{
        int i;
        unsigned a, e;
        struct mem_pieces *mp = &phys_avail;

        for (i = 0; i < mp->n_regions; ++i) {
                a = mp->regions[i].address;
                e = a + mp->regions[i].size;
                a = (a + align - 1) & -align;
                if (a + size <= e) {
                        mem_pieces_remove(mp, a, size, 1);
                        return __va(a);
                }
        }
        panic("Couldn't find %u bytes at %u alignment\n", size, align);

        return NULL;
}

/*
 * Remove some memory from an array of pieces
 */
void __init
mem_pieces_remove(struct mem_pieces *mp, unsigned int start, unsigned int size,
                  int must_exist)
{
        int i, j;
        unsigned int end, rs, re;
        struct reg_property *rp;

        end = start + size;
        for (i = 0, rp = mp->regions; i < mp->n_regions; ++i, ++rp) {
                if (end > rp->address && start < rp->address + rp->size)
                        break;
        }
        if (i >= mp->n_regions) {
                if (must_exist)
                        printk("mem_pieces_remove: [%x,%x) not in any region\n",
                               start, end);
                return;
        }
        for (; i < mp->n_regions && end > rp->address; ++i, ++rp) {
                rs = rp->address;
                re = rs + rp->size;
                if (must_exist && (start < rs || end > re)) {
                        printk("mem_pieces_remove: bad overlap [%x,%x) with",
                               start, end);
                        mem_pieces_print(mp);
                        must_exist = 0;
                }
                if (start > rs) {
                        rp->size = start - rs;
                        if (end < re) {
                                /* need to split this entry */
                                if (mp->n_regions >= MEM_PIECES_MAX)
                                        panic("eek... mem_pieces overflow");
                                for (j = mp->n_regions; j > i + 1; --j)
                                        mp->regions[j] = mp->regions[j-1];
                                ++mp->n_regions;
                                rp[1].address = end;
                                rp[1].size = re - end;
                        }
                } else {
                        if (end < re) {
                                rp->address = end;
                                rp->size = re - end;
                        } else {
                                /* need to delete this entry */
                                for (j = i; j < mp->n_regions - 1; ++j)
                                        mp->regions[j] = mp->regions[j+1];
                                --mp->n_regions;
                                --i;
                                --rp;
                        }
                }
        }
}

static void __init
mem_pieces_print(struct mem_pieces *mp)
{
        int i;

        for (i = 0; i < mp->n_regions; ++i)
                printk(" [%x, %x)", mp->regions[i].address,
                       mp->regions[i].address + mp->regions[i].size);
        printk("\n");
}

#if defined(CONFIG_APUS) || defined(CONFIG_ALL_PPC)
/*
 * Add some memory to an array of pieces
 */
void __init
mem_pieces_append(struct mem_pieces *mp, unsigned int start, unsigned int size)
{
        struct reg_property *rp;

        if (mp->n_regions >= MEM_PIECES_MAX)
                return;
        rp = &mp->regions[mp->n_regions++];
        rp->address = start;
        rp->size = size;
}
#endif /* CONFIG_APUS || CONFIG_ALL_PPC */

void __init
mem_pieces_sort(struct mem_pieces *mp)
{
        unsigned long a, s;
        int i, j;

        for (i = 1; i < mp->n_regions; ++i) {
                a = mp->regions[i].address;
                s = mp->regions[i].size;
                for (j = i - 1; j >= 0; --j) {
                        if (a >= mp->regions[j].address)
                                break;
                        mp->regions[j+1] = mp->regions[j];
                }
                mp->regions[j+1].address = a;
                mp->regions[j+1].size = s;
        }
}

void __init
mem_pieces_coalesce(struct mem_pieces *mp)
{
        unsigned long a, s, ns;
        int i, j, d;

        d = 0;
        for (i = 0; i < mp->n_regions; i = j) {
                a = mp->regions[i].address;
                s = mp->regions[i].size;
                for (j = i + 1; j < mp->n_regions
                             && mp->regions[j].address - a <= s; ++j) {
                        ns = mp->regions[j].address + mp->regions[j].size - a;
                        if (ns > s)
                                s = ns;
                }
                mp->regions[d].address = a;
                mp->regions[d].size = s;
                ++d;
        }
        mp->n_regions = d;
}