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lmb.c

/*
 * 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 <asm/types.h>
#include <asm/page.h>
#include <asm/prom.h>
#include <asm/lmb.h>
#ifdef CONFIG_PPC32
#include "mmu_decl.h"         /* for __max_low_memory */
#endif

#undef DEBUG

#ifdef DEBUG
#include <asm/udbg.h>
#define DBG(fmt...) udbg_printf(fmt)
#else
#define DBG(fmt...)
#endif

#define LMB_ALLOC_ANYWHERE    0

struct lmb lmb;

void lmb_dump_all(void)
{
#ifdef DEBUG
      unsigned long i;

      DBG("lmb_dump_all:\n");
      DBG("    memory.cnt             = 0x%lx\n", lmb.memory.cnt);
      DBG("    memory.size            = 0x%lx\n", lmb.memory.size);
      for (i=0; i < lmb.memory.cnt ;i++) {
            DBG("    memory.region[0x%x].base       = 0x%lx\n",
                      i, lmb.memory.region[i].base);
            DBG("             .size     = 0x%lx\n",
                      lmb.memory.region[i].size);
      }

      DBG("\n    reserved.cnt   = 0x%lx\n", lmb.reserved.cnt);
      DBG("    reserved.size    = 0x%lx\n", lmb.reserved.size);
      for (i=0; i < lmb.reserved.cnt ;i++) {
            DBG("    reserved.region[0x%x].base       = 0x%lx\n",
                      i, lmb.reserved.region[i].base);
            DBG("             .size     = 0x%lx\n",
                      lmb.reserved.region[i].size);
      }
#endif /* DEBUG */
}

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

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

      return 0;
}

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

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

static void __init 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 __init 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);
}

/* This routine called with relocation disabled. */
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;
}

/* This routine may be called with relocation disabled. */
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;
}

/* This routine called with relocation disabled. */
static long __init lmb_add_region(struct lmb_region *rgn, unsigned long base,
                          unsigned long size)
{
      unsigned long coalesced = 0;
      long adjacent, i;

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

      return 0;
}

/* This routine may be called with relocation disabled. */
long __init lmb_add(unsigned long base, unsigned long 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 __init lmb_reserve(unsigned long base, unsigned long 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, unsigned long base,
                        unsigned long size)
{
      unsigned long i;

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

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

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

unsigned long __init lmb_alloc_base(unsigned long size, unsigned long align,
                            unsigned long max_addr)
{
      unsigned long alloc;

      alloc = __lmb_alloc_base(size, align, max_addr);

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

      return alloc;
}

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

      BUG_ON(0 == size);

#ifdef CONFIG_PPC32
      /* On 32-bit, make sure we allocate lowmem */
      if (max_addr == LMB_ALLOC_ANYWHERE)
            max_addr = __max_low_memory;
#endif
      for (i = lmb.memory.cnt-1; i >= 0; i--) {
            unsigned long lmbbase = lmb.memory.region[i].base;
            unsigned long lmbsize = lmb.memory.region[i].size;

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

            while ((lmbbase <= base) &&
                   ((j = lmb_overlaps_region(&lmb.reserved, base, size)) >= 0) )
                  base = _ALIGN_DOWN(lmb.reserved.region[j].base - size,
                                 align);

            if ((base != 0) && (lmbbase <= base))
                  break;
      }

      if (i < 0)
            return 0;

      lmb_add_region(&lmb.reserved, base, size);

      return base;
}

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

unsigned long __init 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(unsigned long memory_limit)
{
      unsigned long i, 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;

      /* 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--;
            }
      }
}

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