/*
 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/bootmem.h>
#include <linux/memblock.h>
#ifdef CONFIG_BLK_DEV_INITRD
#include <linux/initrd.h>
#endif
#include <linux/of_fdt.h>
#include <linux/swap.h>
#include <linux/module.h>
#include <linux/highmem.h>
#include <asm/page.h>
#include <asm/pgalloc.h>
#include <asm/sections.h>
#include <asm/arcregs.h>

pgd_t swapper_pg_dir[PTRS_PER_PGD] __aligned(PAGE_SIZE);
char empty_zero_page[PAGE_SIZE] __aligned(PAGE_SIZE);
EXPORT_SYMBOL(empty_zero_page);

static const unsigned long low_mem_start = CONFIG_LINUX_LINK_BASE;
static unsigned long low_mem_sz;

#ifdef CONFIG_HIGHMEM
static unsigned long min_high_pfn, max_high_pfn;
static u64 high_mem_start;
static u64 high_mem_sz;
#endif

#ifdef CONFIG_DISCONTIGMEM
struct pglist_data node_data[MAX_NUMNODES] __read_mostly;
EXPORT_SYMBOL(node_data);
#endif

/* User can over-ride above with "mem=nnn[KkMm]" in cmdline */
static int __init setup_mem_sz(char *str)
{
        low_mem_sz = memparse(str, NULL) & PAGE_MASK;

        /* early console might not be setup yet - it will show up later */
        pr_info("\"mem=%s\": mem sz set to %ldM\n", str, TO_MB(low_mem_sz));

        return 0;
}
early_param("mem", setup_mem_sz);

void __init early_init_dt_add_memory_arch(u64 base, u64 size)
{
        int in_use = 0;

        if (!low_mem_sz) {
                if (base != low_mem_start)
                        panic("CONFIG_LINUX_LINK_BASE != DT memory { }");

                low_mem_sz = size;
                in_use = 1;
        } else {
#ifdef CONFIG_HIGHMEM
                high_mem_start = base;
                high_mem_sz = size;
                in_use = 1;
#endif
        }

        pr_info("Memory @ %llx [%lldM] %s\n",
                base, TO_MB(size), !in_use ? "Not used":"");
}

#ifdef CONFIG_BLK_DEV_INITRD
static int __init early_initrd(char *p)
{
        unsigned long start, size;
        char *endp;

        start = memparse(p, &endp);
        if (*endp == ',') {
                size = memparse(endp + 1, NULL);

                initrd_start = (unsigned long)__va(start);
                initrd_end = (unsigned long)__va(start + size);
        }
        return 0;
}
early_param("initrd", early_initrd);
#endif

/*
 * First memory setup routine called from setup_arch()
 * 1. setup swapper's mm @init_mm
 * 2. Count the pages we have and setup bootmem allocator
 * 3. zone setup
 */
void __init setup_arch_memory(void)
{
        unsigned long zones_size[MAX_NR_ZONES];
        unsigned long zones_holes[MAX_NR_ZONES];

        init_mm.start_code = (unsigned long)_text;
        init_mm.end_code = (unsigned long)_etext;
        init_mm.end_data = (unsigned long)_edata;
        init_mm.brk = (unsigned long)_end;

        /* first page of system - kernel .vector starts here */
        min_low_pfn = ARCH_PFN_OFFSET;

        /* Last usable page of low mem */
        max_low_pfn = max_pfn = PFN_DOWN(low_mem_start + low_mem_sz);

#ifdef CONFIG_FLATMEM
        /* pfn_valid() uses this */
        max_mapnr = max_low_pfn - min_low_pfn;
#endif

        /*------------- bootmem allocator setup -----------------------*/

        /*
         * seed the bootmem allocator after any DT memory node parsing or
         * "mem=xxx" cmdline overrides have potentially updated @arc_mem_sz
         *
         * Only low mem is added, otherwise we have crashes when allocating
         * mem_map[] itself. NO_BOOTMEM allocates mem_map[] at the end of
         * avail memory, ending in highmem with a > 32-bit address. However
         * it then tries to memset it with a truncaed 32-bit handle, causing
         * the crash
         */

        memblock_add_node(low_mem_start, low_mem_sz, 0);
        memblock_reserve(low_mem_start, __pa(_end) - low_mem_start);

#ifdef CONFIG_BLK_DEV_INITRD
        if (initrd_start)
                memblock_reserve(__pa(initrd_start), initrd_end - initrd_start);
#endif

        early_init_fdt_reserve_self();
        early_init_fdt_scan_reserved_mem();

        memblock_dump_all();

        /*----------------- node/zones setup --------------------------*/
        memset(zones_size, 0, sizeof(zones_size));
        memset(zones_holes, 0, sizeof(zones_holes));

        zones_size[ZONE_NORMAL] = max_low_pfn - min_low_pfn;
        zones_holes[ZONE_NORMAL] = 0;

        /*
         * We can't use the helper free_area_init(zones[]) because it uses
         * PAGE_OFFSET to compute the @min_low_pfn which would be wrong
         * when our kernel doesn't start at PAGE_OFFSET, i.e.
         * PAGE_OFFSET != CONFIG_LINUX_LINK_BASE
         */
        free_area_init_node(0,                  /* node-id */
                            zones_size,         /* num pages per zone */
                            min_low_pfn,        /* first pfn of node */
                            zones_holes);       /* holes */

#ifdef CONFIG_HIGHMEM
        /*
         * Populate a new node with highmem
         *
         * On ARC (w/o PAE) HIGHMEM addresses are actually smaller (0 based)
         * than addresses in normal ala low memory (0x8000_0000 based).
         * Even with PAE, the huge peripheral space hole would waste a lot of
         * mem with single mem_map[]. This warrants a mem_map per region design.
         * Thus HIGHMEM on ARC is imlemented with DISCONTIGMEM.
         *
         * DISCONTIGMEM in turns requires multiple nodes. node 0 above is
         * populated with normal memory zone while node 1 only has highmem
         */
        node_set_online(1);

        min_high_pfn = PFN_DOWN(high_mem_start);
        max_high_pfn = PFN_DOWN(high_mem_start + high_mem_sz);

        zones_size[ZONE_NORMAL] = 0;
        zones_holes[ZONE_NORMAL] = 0;

        zones_size[ZONE_HIGHMEM] = max_high_pfn - min_high_pfn;
        zones_holes[ZONE_HIGHMEM] = 0;

        free_area_init_node(1,                  /* node-id */
                            zones_size,         /* num pages per zone */
                            min_high_pfn,       /* first pfn of node */
                            zones_holes);       /* holes */

        high_memory = (void *)(min_high_pfn << PAGE_SHIFT);
        kmap_init();
#endif
}

/*
 * mem_init - initializes memory
 *
 * Frees up bootmem
 * Calculates and displays memory available/used
 */
void __init mem_init(void)
{
#ifdef CONFIG_HIGHMEM
        unsigned long tmp;

        reset_all_zones_managed_pages();
        for (tmp = min_high_pfn; tmp < max_high_pfn; tmp++)
                free_highmem_page(pfn_to_page(tmp));
#endif

        free_all_bootmem();
        mem_init_print_info(NULL);
}

/*
 * free_initmem: Free all the __init memory.
 */
void __ref free_initmem(void)
{
        free_initmem_default(-1);
}

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