/*
 * arch/xtensa/mm/init.c
 *
 * Derived from MIPS, PPC.
 *
 * 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) 2001 - 2005 Tensilica Inc.
 * Copyright (C) 2014 Cadence Design Systems Inc.
 *
 * Chris Zankel <chris@zankel.net>
 * Joe Taylor   <joe@tensilica.com, joetylr@yahoo.com>
 * Marc Gauthier
 * Kevin Chea
 */

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/bootmem.h>
#include <linux/gfp.h>
#include <linux/highmem.h>
#include <linux/swap.h>
#include <linux/mman.h>
#include <linux/nodemask.h>
#include <linux/mm.h>

#include <asm/bootparam.h>
#include <asm/page.h>
#include <asm/sections.h>
#include <asm/sysmem.h>

struct sysmem_info sysmem __initdata;

static void __init sysmem_dump(void)
{
        unsigned i;

        pr_debug("Sysmem:\n");
        for (i = 0; i < sysmem.nr_banks; ++i)
                pr_debug("  0x%08lx - 0x%08lx (%ldK)\n",
                         sysmem.bank[i].start, sysmem.bank[i].end,
                         (sysmem.bank[i].end - sysmem.bank[i].start) >> 10);
}

/*
 * Find bank with maximal .start such that bank.start <= start
 */
static inline struct meminfo * __init find_bank(unsigned long start)
{
        unsigned i;
        struct meminfo *it = NULL;

        for (i = 0; i < sysmem.nr_banks; ++i)
                if (sysmem.bank[i].start <= start)
                        it = sysmem.bank + i;
                else
                        break;
        return it;
}

/*
 * Move all memory banks starting at 'from' to a new place at 'to',
 * adjust nr_banks accordingly.
 * Both 'from' and 'to' must be inside the sysmem.bank.
 *
 * Returns: 0 (success), -ENOMEM (not enough space in the sysmem.bank).
 */
static int __init move_banks(struct meminfo *to, struct meminfo *from)
{
        unsigned n = sysmem.nr_banks - (from - sysmem.bank);

        if (to > from && to - from + sysmem.nr_banks > SYSMEM_BANKS_MAX)
                return -ENOMEM;
        if (to != from)
                memmove(to, from, n * sizeof(struct meminfo));
        sysmem.nr_banks += to - from;
        return 0;
}

/*
 * Add new bank to sysmem. Resulting sysmem is the union of bytes of the
 * original sysmem and the new bank.
 *
 * Returns: 0 (success), < 0 (error)
 */
int __init add_sysmem_bank(unsigned long start, unsigned long end)
{
        unsigned i;
        struct meminfo *it = NULL;
        unsigned long sz;
        unsigned long bank_sz = 0;

        if (start == end ||
            (start < end) != (PAGE_ALIGN(start) < (end & PAGE_MASK))) {
                pr_warn("Ignoring small memory bank 0x%08lx size: %ld bytes\n",
                        start, end - start);
                return -EINVAL;
        }

        start = PAGE_ALIGN(start);
        end &= PAGE_MASK;
        sz = end - start;

        it = find_bank(start);

        if (it)
                bank_sz = it->end - it->start;

        if (it && bank_sz >= start - it->start) {
                if (end - it->start > bank_sz)
                        it->end = end;
                else
                        return 0;
        } else {
                if (!it)
                        it = sysmem.bank;
                else
                        ++it;

                if (it - sysmem.bank < sysmem.nr_banks &&
                    it->start - start <= sz) {
                        it->start = start;
                        if (it->end - it->start < sz)
                                it->end = end;
                        else
                                return 0;
                } else {
                        if (move_banks(it + 1, it) < 0) {
                                pr_warn("Ignoring memory bank 0x%08lx size %ld bytes\n",
                                        start, end - start);
                                return -EINVAL;
                        }
                        it->start = start;
                        it->end = end;
                        return 0;
                }
        }
        sz = it->end - it->start;
        for (i = it + 1 - sysmem.bank; i < sysmem.nr_banks; ++i)
                if (sysmem.bank[i].start - it->start <= sz) {
                        if (sz < sysmem.bank[i].end - it->start)
                                it->end = sysmem.bank[i].end;
                } else {
                        break;
                }

        move_banks(it + 1, sysmem.bank + i);
        return 0;
}

/*
 * mem_reserve(start, end, must_exist)
 *
 * Reserve some memory from the memory pool.
 * If must_exist is set and a part of the region being reserved does not exist
 * memory map is not altered.
 *
 * Parameters:
 *  start       Start of region,
 *  end         End of region,
 *  must_exist  Must exist in memory pool.
 *
 * Returns:
 *  0 (success)
 *  < 0 (error)
 */

int __init mem_reserve(unsigned long start, unsigned long end, int must_exist)
{
        struct meminfo *it;
        struct meminfo *rm = NULL;
        unsigned long sz;
        unsigned long bank_sz = 0;

        start = start & PAGE_MASK;
        end = PAGE_ALIGN(end);
        sz = end - start;
        if (!sz)
                return -EINVAL;

        it = find_bank(start);

        if (it)
                bank_sz = it->end - it->start;

        if ((!it || end - it->start > bank_sz) && must_exist) {
                pr_warn("mem_reserve: [0x%0lx, 0x%0lx) not in any region!\n",
                        start, end);
                return -EINVAL;
        }

        if (it && start - it->start <= bank_sz) {
                if (start == it->start) {
                        if (end - it->start < bank_sz) {
                                it->start = end;
                                return 0;
                        } else {
                                rm = it;
                        }
                } else {
                        it->end = start;
                        if (end - it->start < bank_sz)
                                return add_sysmem_bank(end,
                                                       it->start + bank_sz);
                        ++it;
                }
        }

        if (!it)
                it = sysmem.bank;

        for (; it < sysmem.bank + sysmem.nr_banks; ++it) {
                if (it->end - start <= sz) {
                        if (!rm)
                                rm = it;
                } else {
                        if (it->start - start < sz)
                                it->start = end;
                        break;
                }
        }

        if (rm)
                move_banks(rm, it);

        return 0;
}


/*
 * Initialize the bootmem system and give it all low memory we have available.
 */

void __init bootmem_init(void)
{
        unsigned long pfn;
        unsigned long bootmap_start, bootmap_size;
        int i;

        sysmem_dump();
        max_low_pfn = max_pfn = 0;
        min_low_pfn = ~0;

        for (i=0; i < sysmem.nr_banks; i++) {
                pfn = PAGE_ALIGN(sysmem.bank[i].start) >> PAGE_SHIFT;
                if (pfn < min_low_pfn)
                        min_low_pfn = pfn;
                pfn = PAGE_ALIGN(sysmem.bank[i].end - 1) >> PAGE_SHIFT;
                if (pfn > max_pfn)
                        max_pfn = pfn;
        }

        if (min_low_pfn > max_pfn)
                panic("No memory found!\n");

        max_low_pfn = max_pfn < MAX_MEM_PFN >> PAGE_SHIFT ?
                max_pfn : MAX_MEM_PFN >> PAGE_SHIFT;

        /* Find an area to use for the bootmem bitmap. */

        bootmap_size = bootmem_bootmap_pages(max_low_pfn - min_low_pfn);
        bootmap_size <<= PAGE_SHIFT;
        bootmap_start = ~0;

        for (i=0; i<sysmem.nr_banks; i++)
                if (sysmem.bank[i].end - sysmem.bank[i].start >= bootmap_size) {
                        bootmap_start = sysmem.bank[i].start;
                        break;
                }

        if (bootmap_start == ~0UL)
                panic("Cannot find %ld bytes for bootmap\n", bootmap_size);

        /* Reserve the bootmem bitmap area */

        mem_reserve(bootmap_start, bootmap_start + bootmap_size, 1);
        bootmap_size = init_bootmem_node(NODE_DATA(0),
                                         bootmap_start >> PAGE_SHIFT,
                                         min_low_pfn,
                                         max_low_pfn);

        /* Add all remaining memory pieces into the bootmem map */

        for (i = 0; i < sysmem.nr_banks; i++) {
                if (sysmem.bank[i].start >> PAGE_SHIFT < max_low_pfn) {
                        unsigned long end = min(max_low_pfn << PAGE_SHIFT,
                                                sysmem.bank[i].end);
                        free_bootmem(sysmem.bank[i].start,
                                     end - sysmem.bank[i].start);
                }
        }

}


void __init zones_init(void)
{
        /* All pages are DMA-able, so we put them all in the DMA zone. */
        unsigned long zones_size[MAX_NR_ZONES] = {
                [ZONE_DMA] = max_low_pfn - ARCH_PFN_OFFSET,
#ifdef CONFIG_HIGHMEM
                [ZONE_HIGHMEM] = max_pfn - max_low_pfn,
#endif
        };
        free_area_init_node(0, zones_size, ARCH_PFN_OFFSET, NULL);
}

/*
 * Initialize memory pages.
 */

void __init mem_init(void)
{
#ifdef CONFIG_HIGHMEM
        unsigned long tmp;

        reset_all_zones_managed_pages();
        for (tmp = max_low_pfn; tmp < max_pfn; tmp++)
                free_highmem_page(pfn_to_page(tmp));
#endif

        max_mapnr = max_pfn - ARCH_PFN_OFFSET;
        high_memory = (void *)__va(max_low_pfn << PAGE_SHIFT);

        free_all_bootmem();

        mem_init_print_info(NULL);
        pr_info("virtual kernel memory layout:\n"
#ifdef CONFIG_HIGHMEM
                "    pkmap   : 0x%08lx - 0x%08lx  (%5lu kB)\n"
                "    fixmap  : 0x%08lx - 0x%08lx  (%5lu kB)\n"
#endif
                "    vmalloc : 0x%08x - 0x%08x  (%5u MB)\n"
                "    lowmem  : 0x%08x - 0x%08lx  (%5lu MB)\n",
#ifdef CONFIG_HIGHMEM
                PKMAP_BASE, PKMAP_BASE + LAST_PKMAP * PAGE_SIZE,
                (LAST_PKMAP*PAGE_SIZE) >> 10,
                FIXADDR_START, FIXADDR_TOP,
                (FIXADDR_TOP - FIXADDR_START) >> 10,
#endif
                VMALLOC_START, VMALLOC_END,
                (VMALLOC_END - VMALLOC_START) >> 20,
                PAGE_OFFSET, PAGE_OFFSET +
                (max_low_pfn - min_low_pfn) * PAGE_SIZE,
                ((max_low_pfn - min_low_pfn) * PAGE_SIZE) >> 20);
}

#ifdef CONFIG_BLK_DEV_INITRD
extern int initrd_is_mapped;

void free_initrd_mem(unsigned long start, unsigned long end)
{
        if (initrd_is_mapped)
                free_reserved_area((void *)start, (void *)end, -1, "initrd");
}
#endif

void free_initmem(void)
{
        free_initmem_default(-1);
}

static void __init parse_memmap_one(char *p)
{
        char *oldp;
        unsigned long start_at, mem_size;

        if (!p)
                return;

        oldp = p;
        mem_size = memparse(p, &p);
        if (p == oldp)
                return;

        switch (*p) {
        case '@':
                start_at = memparse(p + 1, &p);
                add_sysmem_bank(start_at, start_at + mem_size);
                break;

        case '$':
                start_at = memparse(p + 1, &p);
                mem_reserve(start_at, start_at + mem_size, 0);
                break;

        case 0:
                mem_reserve(mem_size, 0, 0);
                break;

        default:
                pr_warn("Unrecognized memmap syntax: %s\n", p);
                break;
        }
}

static int __init parse_memmap_opt(char *str)
{
        while (str) {
                char *k = strchr(str, ',');

                if (k)
                        *k++ = 0;

                parse_memmap_one(str);
                str = k;
        }

        return 0;
}
early_param("memmap", parse_memmap_opt);