/*
 * early_res, could be used to replace bootmem
 */
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/bootmem.h>
#include <linux/mm.h>
#include <linux/early_res.h>
#include <linux/slab.h>
#include <linux/kmemleak.h>

/*
 * Early reserved memory areas.
 */
/*
 * need to make sure this one is bigger enough before
 * find_fw_memmap_area could be used
 */
#define MAX_EARLY_RES_X 32

struct early_res {
        u64 start, end;
        char name[15];
        char overlap_ok;
};
static struct early_res early_res_x[MAX_EARLY_RES_X] __initdata;

static int max_early_res __initdata = MAX_EARLY_RES_X;
static struct early_res *early_res __initdata = &early_res_x[0];
static int early_res_count __initdata;

static int __init find_overlapped_early(u64 start, u64 end)
{
        int i;
        struct early_res *r;

        for (i = 0; i < max_early_res && early_res[i].end; i++) {
                r = &early_res[i];
                if (end > r->start && start < r->end)
                        break;
        }

        return i;
}

/*
 * Drop the i-th range from the early reservation map,
 * by copying any higher ranges down one over it, and
 * clearing what had been the last slot.
 */
static void __init drop_range(int i)
{
        int j;

        for (j = i + 1; j < max_early_res && early_res[j].end; j++)
                ;

        memmove(&early_res[i], &early_res[i + 1],
               (j - 1 - i) * sizeof(struct early_res));

        early_res[j - 1].end = 0;
        early_res_count--;
}

static void __init drop_range_partial(int i, u64 start, u64 end)
{
        u64 common_start, common_end;
        u64 old_start, old_end;

        old_start = early_res[i].start;
        old_end = early_res[i].end;
        common_start = max(old_start, start);
        common_end = min(old_end, end);

        /* no overlap ? */
        if (common_start >= common_end)
                return;

        if (old_start < common_start) {
                /* make head segment */
                early_res[i].end = common_start;
                if (old_end > common_end) {
                        char name[15];

                        /*
                         * Save a local copy of the name, since the
                         * early_res array could get resized inside
                         * reserve_early_without_check() ->
                         * __check_and_double_early_res(), which would
                         * make the current name pointer invalid.
                         */
                        strncpy(name, early_res[i].name,
                                         sizeof(early_res[i].name) - 1);
                        /* add another for left over on tail */
                        reserve_early_without_check(common_end, old_end, name);
                }
                return;
        } else {
                if (old_end > common_end) {
                        /* reuse the entry for tail left */
                        early_res[i].start = common_end;
                        return;
                }
                /* all covered */
                drop_range(i);
        }
}

/*
 * Split any existing ranges that:
 *  1) are marked 'overlap_ok', and
 *  2) overlap with the stated range [start, end)
 * into whatever portion (if any) of the existing range is entirely
 * below or entirely above the stated range.  Drop the portion
 * of the existing range that overlaps with the stated range,
 * which will allow the caller of this routine to then add that
 * stated range without conflicting with any existing range.
 */
static void __init drop_overlaps_that_are_ok(u64 start, u64 end)
{
        int i;
        struct early_res *r;
        u64 lower_start, lower_end;
        u64 upper_start, upper_end;
        char name[15];

        for (i = 0; i < max_early_res && early_res[i].end; i++) {
                r = &early_res[i];

                /* Continue past non-overlapping ranges */
                if (end <= r->start || start >= r->end)
                        continue;

                /*
                 * Leave non-ok overlaps as is; let caller
                 * panic "Overlapping early reservations"
                 * when it hits this overlap.
                 */
                if (!r->overlap_ok)
                        return;

                /*
                 * We have an ok overlap.  We will drop it from the early
                 * reservation map, and add back in any non-overlapping
                 * portions (lower or upper) as separate, overlap_ok,
                 * non-overlapping ranges.
                 */

                /* 1. Note any non-overlapping (lower or upper) ranges. */
                strncpy(name, r->name, sizeof(name) - 1);

                lower_start = lower_end = 0;
                upper_start = upper_end = 0;
                if (r->start < start) {
                        lower_start = r->start;
                        lower_end = start;
                }
                if (r->end > end) {
                        upper_start = end;
                        upper_end = r->end;
                }

                /* 2. Drop the original ok overlapping range */
                drop_range(i);

                i--;            /* resume for-loop on copied down entry */

                /* 3. Add back in any non-overlapping ranges. */
                if (lower_end)
                        reserve_early_overlap_ok(lower_start, lower_end, name);
                if (upper_end)
                        reserve_early_overlap_ok(upper_start, upper_end, name);
        }
}

static void __init __reserve_early(u64 start, u64 end, char *name,
                                                int overlap_ok)
{
        int i;
        struct early_res *r;

        i = find_overlapped_early(start, end);
        if (i >= max_early_res)
                panic("Too many early reservations");
        r = &early_res[i];
        if (r->end)
                panic("Overlapping early reservations "
                      "%llx-%llx %s to %llx-%llx %s\n",
                      start, end - 1, name ? name : "", r->start,
                      r->end - 1, r->name);
        r->start = start;
        r->end = end;
        r->overlap_ok = overlap_ok;
        if (name)
                strncpy(r->name, name, sizeof(r->name) - 1);
        early_res_count++;
}

/*
 * A few early reservtations come here.
 *
 * The 'overlap_ok' in the name of this routine does -not- mean it
 * is ok for these reservations to overlap an earlier reservation.
 * Rather it means that it is ok for subsequent reservations to
 * overlap this one.
 *
 * Use this entry point to reserve early ranges when you are doing
 * so out of "Paranoia", reserving perhaps more memory than you need,
 * just in case, and don't mind a subsequent overlapping reservation
 * that is known to be needed.
 *
 * The drop_overlaps_that_are_ok() call here isn't really needed.
 * It would be needed if we had two colliding 'overlap_ok'
 * reservations, so that the second such would not panic on the
 * overlap with the first.  We don't have any such as of this
 * writing, but might as well tolerate such if it happens in
 * the future.
 */
void __init reserve_early_overlap_ok(u64 start, u64 end, char *name)
{
        drop_overlaps_that_are_ok(start, end);
        __reserve_early(start, end, name, 1);
}

static void __init __check_and_double_early_res(u64 ex_start, u64 ex_end)
{
        u64 start, end, size, mem;
        struct early_res *new;

        /* do we have enough slots left ? */
        if ((max_early_res - early_res_count) > max(max_early_res/8, 2))
                return;

        /* double it */
        mem = -1ULL;
        size = sizeof(struct early_res) * max_early_res * 2;
        if (early_res == early_res_x)
                start = 0;
        else
                start = early_res[0].end;
        end = ex_start;
        if (start + size < end)
                mem = find_fw_memmap_area(start, end, size,
                                         sizeof(struct early_res));
        if (mem == -1ULL) {
                start = ex_end;
                end = get_max_mapped();
                if (start + size < end)
                        mem = find_fw_memmap_area(start, end, size,
                                                 sizeof(struct early_res));
        }
        if (mem == -1ULL)
                panic("can not find more space for early_res array");

        new = __va(mem);
        /* save the first one for own */
        new[0].start = mem;
        new[0].end = mem + size;
        new[0].overlap_ok = 0;
        /* copy old to new */
        if (early_res == early_res_x) {
                memcpy(&new[1], &early_res[0],
                         sizeof(struct early_res) * max_early_res);
                memset(&new[max_early_res+1], 0,
                         sizeof(struct early_res) * (max_early_res - 1));
                early_res_count++;
        } else {
                memcpy(&new[1], &early_res[1],
                         sizeof(struct early_res) * (max_early_res - 1));
                memset(&new[max_early_res], 0,
                         sizeof(struct early_res) * max_early_res);
        }
        memset(&early_res[0], 0, sizeof(struct early_res) * max_early_res);
        early_res = new;
        max_early_res *= 2;
        printk(KERN_DEBUG "early_res array is doubled to %d at [%llx - %llx]\n",
                max_early_res, mem, mem + size - 1);
}

/*
 * Most early reservations come here.
 *
 * We first have drop_overlaps_that_are_ok() drop any pre-existing
 * 'overlap_ok' ranges, so that we can then reserve this memory
 * range without risk of panic'ing on an overlapping overlap_ok
 * early reservation.
 */
void __init reserve_early(u64 start, u64 end, char *name)
{
        if (start >= end)
                return;

        __check_and_double_early_res(start, end);

        drop_overlaps_that_are_ok(start, end);
        __reserve_early(start, end, name, 0);
}

void __init reserve_early_without_check(u64 start, u64 end, char *name)
{
        struct early_res *r;

        if (start >= end)
                return;

        __check_and_double_early_res(start, end);

        r = &early_res[early_res_count];

        r->start = start;
        r->end = end;
        r->overlap_ok = 0;
        if (name)
                strncpy(r->name, name, sizeof(r->name) - 1);
        early_res_count++;
}

void __init free_early(u64 start, u64 end)
{
        struct early_res *r;
        int i;

        kmemleak_free_part(__va(start), end - start);

        i = find_overlapped_early(start, end);
        r = &early_res[i];
        if (i >= max_early_res || r->end != end || r->start != start)
                panic("free_early on not reserved area: %llx-%llx!",
                         start, end - 1);

        drop_range(i);
}

void __init free_early_partial(u64 start, u64 end)
{
        struct early_res *r;
        int i;

        kmemleak_free_part(__va(start), end - start);

        if (start == end)
                return;

        if (WARN_ONCE(start > end, "  wrong range [%#llx, %#llx]\n", start, end))
                return;

try_next:
        i = find_overlapped_early(start, end);
        if (i >= max_early_res)
                return;

        r = &early_res[i];
        /* hole ? */
        if (r->end >= end && r->start <= start) {
                drop_range_partial(i, start, end);
                return;
        }

        drop_range_partial(i, start, end);
        goto try_next;
}

#ifdef CONFIG_NO_BOOTMEM
static void __init subtract_early_res(struct range *range, int az)
{
        int i, count;
        u64 final_start, final_end;
        int idx = 0;

        count  = 0;
        for (i = 0; i < max_early_res && early_res[i].end; i++)
                count++;

        /* need to skip first one ?*/
        if (early_res != early_res_x)
                idx = 1;

#define DEBUG_PRINT_EARLY_RES 1

#if DEBUG_PRINT_EARLY_RES
        printk(KERN_INFO "Subtract (%d early reservations)\n", count);
#endif
        for (i = idx; i < count; i++) {
                struct early_res *r = &early_res[i];
#if DEBUG_PRINT_EARLY_RES
                printk(KERN_INFO "  #%d [%010llx - %010llx] %15s\n", i,
                        r->start, r->end, r->name);
#endif
                final_start = PFN_DOWN(r->start);
                final_end = PFN_UP(r->end);
                if (final_start >= final_end)
                        continue;
                subtract_range(range, az, final_start, final_end);
        }

}

int __init get_free_all_memory_range(struct range **rangep, int nodeid)
{
        int i, count;
        u64 start = 0, end;
        u64 size;
        u64 mem;
        struct range *range;
        int nr_range;

        count  = 0;
        for (i = 0; i < max_early_res && early_res[i].end; i++)
                count++;

        count *= 2;

        size = sizeof(struct range) * count;
        end = get_max_mapped();
#ifdef MAX_DMA32_PFN
        if (end > (MAX_DMA32_PFN << PAGE_SHIFT))
                start = MAX_DMA32_PFN << PAGE_SHIFT;
#endif
        mem = find_fw_memmap_area(start, end, size, sizeof(struct range));
        if (mem == -1ULL)
                panic("can not find more space for range free");

        range = __va(mem);
        /* use early_node_map[] and early_res to get range array at first */
        memset(range, 0, size);
        nr_range = 0;

        /* need to go over early_node_map to find out good range for node */
        nr_range = add_from_early_node_map(range, count, nr_range, nodeid);
#ifdef CONFIG_X86_32
        subtract_range(range, count, max_low_pfn, -1ULL);
#endif
        subtract_early_res(range, count);
        nr_range = clean_sort_range(range, count);

        /* need to clear it ? */
        if (nodeid == MAX_NUMNODES) {
                memset(&early_res[0], 0,
                         sizeof(struct early_res) * max_early_res);
                early_res = NULL;
                max_early_res = 0;
        }

        *rangep = range;
        return nr_range;
}
#else
void __init early_res_to_bootmem(u64 start, u64 end)
{
        int i, count;
        u64 final_start, final_end;
        int idx = 0;

        count  = 0;
        for (i = 0; i < max_early_res && early_res[i].end; i++)
                count++;

        /* need to skip first one ?*/
        if (early_res != early_res_x)
                idx = 1;

        printk(KERN_INFO "(%d/%d early reservations) ==> bootmem [%010llx - %010llx]\n",
                         count - idx, max_early_res, start, end);
        for (i = idx; i < count; i++) {
                struct early_res *r = &early_res[i];
                printk(KERN_INFO "  #%d [%010llx - %010llx] %16s", i,
                        r->start, r->end, r->name);
                final_start = max(start, r->start);
                final_end = min(end, r->end);
                if (final_start >= final_end) {
                        printk(KERN_CONT "\n");
                        continue;
                }
                printk(KERN_CONT " ==> [%010llx - %010llx]\n",
                        final_start, final_end);
                reserve_bootmem_generic(final_start, final_end - final_start,
                                BOOTMEM_DEFAULT);
        }
        /* clear them */
        memset(&early_res[0], 0, sizeof(struct early_res) * max_early_res);
        early_res = NULL;
        max_early_res = 0;
        early_res_count = 0;
}
#endif

/* Check for already reserved areas */
static inline int __init bad_addr(u64 *addrp, u64 size, u64 align)
{
        int i;
        u64 addr = *addrp;
        int changed = 0;
        struct early_res *r;
again:
        i = find_overlapped_early(addr, addr + size);
        r = &early_res[i];
        if (i < max_early_res && r->end) {
                *addrp = addr = round_up(r->end, align);
                changed = 1;
                goto again;
        }
        return changed;
}

/* Check for already reserved areas */
static inline int __init bad_addr_size(u64 *addrp, u64 *sizep, u64 align)
{
        int i;
        u64 addr = *addrp, last;
        u64 size = *sizep;
        int changed = 0;
again:
        last = addr + size;
        for (i = 0; i < max_early_res && early_res[i].end; i++) {
                struct early_res *r = &early_res[i];
                if (last > r->start && addr < r->start) {
                        size = r->start - addr;
                        changed = 1;
                        goto again;
                }
                if (last > r->end && addr < r->end) {
                        addr = round_up(r->end, align);
                        size = last - addr;
                        changed = 1;
                        goto again;
                }
                if (last <= r->end && addr >= r->start) {
                        (*sizep)++;
                        return 0;
                }
        }
        if (changed) {
                *addrp = addr;
                *sizep = size;
        }
        return changed;
}

/*
 * Find a free area with specified alignment in a specific range.
 * only with the area.between start to end is active range from early_node_map
 * so they are good as RAM
 */
u64 __init find_early_area(u64 ei_start, u64 ei_last, u64 start, u64 end,
                         u64 size, u64 align)
{
        u64 addr, last;

        addr = round_up(ei_start, align);
        if (addr < start)
                addr = round_up(start, align);
        if (addr >= ei_last)
                goto out;
        while (bad_addr(&addr, size, align) && addr+size <= ei_last)
                ;
        last = addr + size;
        if (last > ei_last)
                goto out;
        if (last > end)
                goto out;

        return addr;

out:
        return -1ULL;
}

u64 __init find_early_area_size(u64 ei_start, u64 ei_last, u64 start,
                         u64 *sizep, u64 align)
{
        u64 addr, last;

        addr = round_up(ei_start, align);
        if (addr < start)
                addr = round_up(start, align);
        if (addr >= ei_last)
                goto out;
        *sizep = ei_last - addr;
        while (bad_addr_size(&addr, sizep, align) && addr + *sizep <= ei_last)
                ;
        last = addr + *sizep;
        if (last > ei_last)
                goto out;

        return addr;

out:
        return -1ULL;
}