/*
 * Procedures for maintaining information about logical memory blocks.
 *
 * Peter Bergner, IBM Corp.     June 2001.
 * Copyright (C) 2001 Peter Bergner.
 *
 *      This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License
 *      as published by the Free Software Foundation; either version
 *      2 of the License, or (at your option) any later version.
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/bitops.h>
#include <linux/lmb.h>

#define LMB_ALLOC_ANYWHERE      0

struct lmb lmb;

static int lmb_debug;

static int __init early_lmb(char *p)
{
        if (p && strstr(p, "debug"))
                lmb_debug = 1;
        return 0;
}
early_param("lmb", early_lmb);

static void lmb_dump(struct lmb_region *region, char *name)
{
        unsigned long long base, size;
        int i;

        pr_info(" %s.cnt  = 0x%lx\n", name, region->cnt);

        for (i = 0; i < region->cnt; i++) {
                base = region->region[i].base;
                size = region->region[i].size;

                pr_info(" %s[0x%x]\t0x%016llx - 0x%016llx, 0x%llx bytes\n",
                    name, i, base, base + size - 1, size);
        }
}

void lmb_dump_all(void)
{
        if (!lmb_debug)
                return;

        pr_info("LMB configuration:\n");
        pr_info(" rmo_size    = 0x%llx\n", (unsigned long long)lmb.rmo_size);
        pr_info(" memory.size = 0x%llx\n", (unsigned long long)lmb.memory.size);

        lmb_dump(&lmb.memory, "memory");
        lmb_dump(&lmb.reserved, "reserved");
}

static unsigned long lmb_addrs_overlap(u64 base1, u64 size1, u64 base2,
                                        u64 size2)
{
        return ((base1 < (base2 + size2)) && (base2 < (base1 + size1)));
}

static long lmb_addrs_adjacent(u64 base1, u64 size1, u64 base2, u64 size2)
{
        if (base2 == base1 + size1)
                return 1;
        else if (base1 == base2 + size2)
                return -1;

        return 0;
}

static long lmb_regions_adjacent(struct lmb_region *rgn,
                unsigned long r1, unsigned long r2)
{
        u64 base1 = rgn->region[r1].base;
        u64 size1 = rgn->region[r1].size;
        u64 base2 = rgn->region[r2].base;
        u64 size2 = rgn->region[r2].size;

        return lmb_addrs_adjacent(base1, size1, base2, size2);
}

static void lmb_remove_region(struct lmb_region *rgn, unsigned long r)
{
        unsigned long i;

        for (i = r; i < rgn->cnt - 1; i++) {
                rgn->region[i].base = rgn->region[i + 1].base;
                rgn->region[i].size = rgn->region[i + 1].size;
        }
        rgn->cnt--;
}

/* Assumption: base addr of region 1 < base addr of region 2 */
static void lmb_coalesce_regions(struct lmb_region *rgn,
                unsigned long r1, unsigned long r2)
{
        rgn->region[r1].size += rgn->region[r2].size;
        lmb_remove_region(rgn, r2);
}

void __init lmb_init(void)
{
        /* Create a dummy zero size LMB which will get coalesced away later.
         * This simplifies the lmb_add() code below...
         */
        lmb.memory.region[0].base = 0;
        lmb.memory.region[0].size = 0;
        lmb.memory.cnt = 1;

        /* Ditto. */
        lmb.reserved.region[0].base = 0;
        lmb.reserved.region[0].size = 0;
        lmb.reserved.cnt = 1;
}

void __init lmb_analyze(void)
{
        int i;

        lmb.memory.size = 0;

        for (i = 0; i < lmb.memory.cnt; i++)
                lmb.memory.size += lmb.memory.region[i].size;
}

static long lmb_add_region(struct lmb_region *rgn, u64 base, u64 size)
{
        unsigned long coalesced = 0;
        long adjacent, i;

        if ((rgn->cnt == 1) && (rgn->region[0].size == 0)) {
                rgn->region[0].base = base;
                rgn->region[0].size = size;
                return 0;
        }

        /* First try and coalesce this LMB with another. */
        for (i = 0; i < rgn->cnt; i++) {
                u64 rgnbase = rgn->region[i].base;
                u64 rgnsize = rgn->region[i].size;

                if ((rgnbase == base) && (rgnsize == size))
                        /* Already have this region, so we're done */
                        return 0;

                adjacent = lmb_addrs_adjacent(base, size, rgnbase, rgnsize);
                if (adjacent > 0) {
                        rgn->region[i].base -= size;
                        rgn->region[i].size += size;
                        coalesced++;
                        break;
                } else if (adjacent < 0) {
                        rgn->region[i].size += size;
                        coalesced++;
                        break;
                }
        }

        if ((i < rgn->cnt - 1) && lmb_regions_adjacent(rgn, i, i+1)) {
                lmb_coalesce_regions(rgn, i, i+1);
                coalesced++;
        }

        if (coalesced)
                return coalesced;
        if (rgn->cnt >= MAX_LMB_REGIONS)
                return -1;

        /* Couldn't coalesce the LMB, so add it to the sorted table. */
        for (i = rgn->cnt - 1; i >= 0; i--) {
                if (base < rgn->region[i].base) {
                        rgn->region[i+1].base = rgn->region[i].base;
                        rgn->region[i+1].size = rgn->region[i].size;
                } else {
                        rgn->region[i+1].base = base;
                        rgn->region[i+1].size = size;
                        break;
                }
        }

        if (base < rgn->region[0].base) {
                rgn->region[0].base = base;
                rgn->region[0].size = size;
        }
        rgn->cnt++;

        return 0;
}

long lmb_add(u64 base, u64 size)
{
        struct lmb_region *_rgn = &lmb.memory;

        /* On pSeries LPAR systems, the first LMB is our RMO region. */
        if (base == 0)
                lmb.rmo_size = size;

        return lmb_add_region(_rgn, base, size);

}

long lmb_remove(u64 base, u64 size)
{
        struct lmb_region *rgn = &(lmb.memory);
        u64 rgnbegin, rgnend;
        u64 end = base + size;
        int i;

        rgnbegin = rgnend = 0; /* supress gcc warnings */

        /* Find the region where (base, size) belongs to */
        for (i=0; i < rgn->cnt; i++) {
                rgnbegin = rgn->region[i].base;
                rgnend = rgnbegin + rgn->region[i].size;

                if ((rgnbegin <= base) && (end <= rgnend))
                        break;
        }

        /* Didn't find the region */
        if (i == rgn->cnt)
                return -1;

        /* Check to see if we are removing entire region */
        if ((rgnbegin == base) && (rgnend == end)) {
                lmb_remove_region(rgn, i);
                return 0;
        }

        /* Check to see if region is matching at the front */
        if (rgnbegin == base) {
                rgn->region[i].base = end;
                rgn->region[i].size -= size;
                return 0;
        }

        /* Check to see if the region is matching at the end */
        if (rgnend == end) {
                rgn->region[i].size -= size;
                return 0;
        }

        /*
         * We need to split the entry -  adjust the current one to the
         * beginging of the hole and add the region after hole.
         */
        rgn->region[i].size = base - rgn->region[i].base;
        return lmb_add_region(rgn, end, rgnend - end);
}

long __init lmb_reserve(u64 base, u64 size)
{
        struct lmb_region *_rgn = &lmb.reserved;

        BUG_ON(0 == size);

        return lmb_add_region(_rgn, base, size);
}

long __init lmb_overlaps_region(struct lmb_region *rgn, u64 base, u64 size)
{
        unsigned long i;

        for (i = 0; i < rgn->cnt; i++) {
                u64 rgnbase = rgn->region[i].base;
                u64 rgnsize = rgn->region[i].size;
                if (lmb_addrs_overlap(base, size, rgnbase, rgnsize))
                        break;
        }

        return (i < rgn->cnt) ? i : -1;
}

static u64 lmb_align_down(u64 addr, u64 size)
{
        return addr & ~(size - 1);
}

static u64 lmb_align_up(u64 addr, u64 size)
{
        return (addr + (size - 1)) & ~(size - 1);
}

static u64 __init lmb_alloc_nid_unreserved(u64 start, u64 end,
                                           u64 size, u64 align)
{
        u64 base, res_base;
        long j;

        base = lmb_align_down((end - size), align);
        while (start <= base) {
                j = lmb_overlaps_region(&lmb.reserved, base, size);
                if (j < 0) {
                        /* this area isn't reserved, take it */
                        if (lmb_add_region(&lmb.reserved, base, size) < 0)
                                base = ~(u64)0;
                        return base;
                }
                res_base = lmb.reserved.region[j].base;
                if (res_base < size)
                        break;
                base = lmb_align_down(res_base - size, align);
        }

        return ~(u64)0;
}

static u64 __init lmb_alloc_nid_region(struct lmb_property *mp,
                                       u64 (*nid_range)(u64, u64, int *),
                                       u64 size, u64 align, int nid)
{
        u64 start, end;

        start = mp->base;
        end = start + mp->size;

        start = lmb_align_up(start, align);
        while (start < end) {
                u64 this_end;
                int this_nid;

                this_end = nid_range(start, end, &this_nid);
                if (this_nid == nid) {
                        u64 ret = lmb_alloc_nid_unreserved(start, this_end,
                                                           size, align);
                        if (ret != ~(u64)0)
                                return ret;
                }
                start = this_end;
        }

        return ~(u64)0;
}

u64 __init lmb_alloc_nid(u64 size, u64 align, int nid,
                         u64 (*nid_range)(u64 start, u64 end, int *nid))
{
        struct lmb_region *mem = &lmb.memory;
        int i;

        BUG_ON(0 == size);

        size = lmb_align_up(size, align);

        for (i = 0; i < mem->cnt; i++) {
                u64 ret = lmb_alloc_nid_region(&mem->region[i],
                                               nid_range,
                                               size, align, nid);
                if (ret != ~(u64)0)
                        return ret;
        }

        return lmb_alloc(size, align);
}

u64 __init lmb_alloc(u64 size, u64 align)
{
        return lmb_alloc_base(size, align, LMB_ALLOC_ANYWHERE);
}

u64 __init lmb_alloc_base(u64 size, u64 align, u64 max_addr)
{
        u64 alloc;

        alloc = __lmb_alloc_base(size, align, max_addr);

        if (alloc == 0)
                panic("ERROR: Failed to allocate 0x%llx bytes below 0x%llx.\n",
                      (unsigned long long) size, (unsigned long long) max_addr);

        return alloc;
}

u64 __init __lmb_alloc_base(u64 size, u64 align, u64 max_addr)
{
        long i, j;
        u64 base = 0;
        u64 res_base;

        BUG_ON(0 == size);

        size = lmb_align_up(size, align);

        /* On some platforms, make sure we allocate lowmem */
        /* Note that LMB_REAL_LIMIT may be LMB_ALLOC_ANYWHERE */
        if (max_addr == LMB_ALLOC_ANYWHERE)
                max_addr = LMB_REAL_LIMIT;

        for (i = lmb.memory.cnt - 1; i >= 0; i--) {
                u64 lmbbase = lmb.memory.region[i].base;
                u64 lmbsize = lmb.memory.region[i].size;

                if (lmbsize < size)
                        continue;
                if (max_addr == LMB_ALLOC_ANYWHERE)
                        base = lmb_align_down(lmbbase + lmbsize - size, align);
                else if (lmbbase < max_addr) {
                        base = min(lmbbase + lmbsize, max_addr);
                        base = lmb_align_down(base - size, align);
                } else
                        continue;

                while (base && lmbbase <= base) {
                        j = lmb_overlaps_region(&lmb.reserved, base, size);
                        if (j < 0) {
                                /* this area isn't reserved, take it */
                                if (lmb_add_region(&lmb.reserved, base, size) < 0)
                                        return 0;
                                return base;
                        }
                        res_base = lmb.reserved.region[j].base;
                        if (res_base < size)
                                break;
                        base = lmb_align_down(res_base - size, align);
                }
        }
        return 0;
}

/* You must call lmb_analyze() before this. */
u64 __init lmb_phys_mem_size(void)
{
        return lmb.memory.size;
}

u64 lmb_end_of_DRAM(void)
{
        int idx = lmb.memory.cnt - 1;

        return (lmb.memory.region[idx].base + lmb.memory.region[idx].size);
}

/* You must call lmb_analyze() after this. */
void __init lmb_enforce_memory_limit(u64 memory_limit)
{
        unsigned long i;
        u64 limit;
        struct lmb_property *p;

        if (!memory_limit)
                return;

        /* Truncate the lmb regions to satisfy the memory limit. */
        limit = memory_limit;
        for (i = 0; i < lmb.memory.cnt; i++) {
                if (limit > lmb.memory.region[i].size) {
                        limit -= lmb.memory.region[i].size;
                        continue;
                }

                lmb.memory.region[i].size = limit;
                lmb.memory.cnt = i + 1;
                break;
        }

        if (lmb.memory.region[0].size < lmb.rmo_size)
                lmb.rmo_size = lmb.memory.region[0].size;

        memory_limit = lmb_end_of_DRAM();

        /* And truncate any reserves above the limit also. */
        for (i = 0; i < lmb.reserved.cnt; i++) {
                p = &lmb.reserved.region[i];

                if (p->base > memory_limit)
                        p->size = 0;
                else if ((p->base + p->size) > memory_limit)
                        p->size = memory_limit - p->base;

                if (p->size == 0) {
                        lmb_remove_region(&lmb.reserved, i);
                        i--;
                }
        }
}

int __init lmb_is_reserved(u64 addr)
{
        int i;

        for (i = 0; i < lmb.reserved.cnt; i++) {
                u64 upper = lmb.reserved.region[i].base +
                        lmb.reserved.region[i].size - 1;
                if ((addr >= lmb.reserved.region[i].base) && (addr <= upper))
                        return 1;
        }
        return 0;
}

/*
 * Given a <base, len>, find which memory regions belong to this range.
 * Adjust the request and return a contiguous chunk.
 */
int lmb_find(struct lmb_property *res)
{
        int i;
        u64 rstart, rend;

        rstart = res->base;
        rend = rstart + res->size - 1;

        for (i = 0; i < lmb.memory.cnt; i++) {
                u64 start = lmb.memory.region[i].base;
                u64 end = start + lmb.memory.region[i].size - 1;

                if (start > rend)
                        return -1;

                if ((end >= rstart) && (start < rend)) {
                        /* adjust the request */
                        if (rstart < start)
                                rstart = start;
                        if (rend > end)
                                rend = end;
                        res->base = rstart;
                        res->size = rend - rstart + 1;
                        return 0;
                }
        }
        return -1;
}