/*
 *  Copyright (C) 2005,2006,2007,2008,2009,2010 Imagination Technologies
 *
 */

#include <linux/export.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/init.h>
#include <linux/bootmem.h>
#include <linux/pagemap.h>
#include <linux/percpu.h>
#include <linux/memblock.h>
#include <linux/initrd.h>
#include <linux/sched/task.h>

#include <asm/setup.h>
#include <asm/page.h>
#include <asm/pgalloc.h>
#include <asm/mmu.h>
#include <asm/mmu_context.h>
#include <asm/sections.h>
#include <asm/tlb.h>
#include <asm/user_gateway.h>
#include <asm/mmzone.h>
#include <asm/fixmap.h>

unsigned long pfn_base;
EXPORT_SYMBOL(pfn_base);

pgd_t swapper_pg_dir[PTRS_PER_PGD] __page_aligned_data;

unsigned long empty_zero_page;
EXPORT_SYMBOL(empty_zero_page);

extern char __user_gateway_start;
extern char __user_gateway_end;

void *gateway_page;

/*
 * Insert the gateway page into a set of page tables, creating the
 * page tables if necessary.
 */
static void insert_gateway_page(pgd_t *pgd, unsigned long address)
{
        pud_t *pud;
        pmd_t *pmd;
        pte_t *pte;

        BUG_ON(!pgd_present(*pgd));

        pud = pud_offset(pgd, address);
        BUG_ON(!pud_present(*pud));

        pmd = pmd_offset(pud, address);
        if (!pmd_present(*pmd)) {
                pte = alloc_bootmem_pages(PAGE_SIZE);
                set_pmd(pmd, __pmd(_PAGE_TABLE | __pa(pte)));
        }

        pte = pte_offset_kernel(pmd, address);
        set_pte(pte, pfn_pte(__pa(gateway_page) >> PAGE_SHIFT, PAGE_READONLY));
}

/* Alloc and map a page in a known location accessible to userspace. */
static void __init user_gateway_init(void)
{
        unsigned long address = USER_GATEWAY_PAGE;
        int offset = pgd_index(address);
        pgd_t *pgd;

        gateway_page = alloc_bootmem_pages(PAGE_SIZE);

        pgd = swapper_pg_dir + offset;
        insert_gateway_page(pgd, address);

#ifdef CONFIG_METAG_META12
        /*
         * Insert the gateway page into our current page tables even
         * though we've already inserted it into our reference page
         * table (swapper_pg_dir). This is because with a META1 mmu we
         * copy just the user address range and not the gateway page
         * entry on context switch, see switch_mmu().
         */
        pgd = (pgd_t *)mmu_get_base() + offset;
        insert_gateway_page(pgd, address);
#endif /* CONFIG_METAG_META12 */

        BUG_ON((&__user_gateway_end - &__user_gateway_start) > PAGE_SIZE);

        gateway_page += (address & ~PAGE_MASK);

        memcpy(gateway_page, &__user_gateway_start,
               &__user_gateway_end - &__user_gateway_start);

        /*
         * We don't need to flush the TLB here, there should be no mapping
         * present at boot for this address and only valid mappings are in
         * the TLB (apart from on Meta 1.x, but those cached invalid
         * mappings should be impossible to hit here).
         *
         * We don't flush the code cache here even though we have written
         * code through the data cache and they may not be coherent. At
         * this point we assume there is no stale data in the code cache
         * for this address so there is no need to flush.
         */
}

static void __init allocate_pgdat(unsigned int nid)
{
        unsigned long start_pfn, end_pfn;
#ifdef CONFIG_NEED_MULTIPLE_NODES
        unsigned long phys;
#endif

        get_pfn_range_for_nid(nid, &start_pfn, &end_pfn);

#ifdef CONFIG_NEED_MULTIPLE_NODES
        phys = __memblock_alloc_base(sizeof(struct pglist_data),
                                SMP_CACHE_BYTES, end_pfn << PAGE_SHIFT);
        /* Retry with all of system memory */
        if (!phys)
                phys = __memblock_alloc_base(sizeof(struct pglist_data),
                                             SMP_CACHE_BYTES,
                                             memblock_end_of_DRAM());
        if (!phys)
                panic("Can't allocate pgdat for node %d\n", nid);

        NODE_DATA(nid) = __va(phys);
        memset(NODE_DATA(nid), 0, sizeof(struct pglist_data));

        NODE_DATA(nid)->bdata = &bootmem_node_data[nid];
#endif

        NODE_DATA(nid)->node_start_pfn = start_pfn;
        NODE_DATA(nid)->node_spanned_pages = end_pfn - start_pfn;
}

static void __init bootmem_init_one_node(unsigned int nid)
{
        unsigned long total_pages, paddr;
        unsigned long end_pfn;
        struct pglist_data *p;

        p = NODE_DATA(nid);

        /* Nothing to do.. */
        if (!p->node_spanned_pages)
                return;

        end_pfn = pgdat_end_pfn(p);
#ifdef CONFIG_HIGHMEM
        if (end_pfn > max_low_pfn)
                end_pfn = max_low_pfn;
#endif

        total_pages = bootmem_bootmap_pages(end_pfn - p->node_start_pfn);

        paddr = memblock_alloc(total_pages << PAGE_SHIFT, PAGE_SIZE);
        if (!paddr)
                panic("Can't allocate bootmap for nid[%d]\n", nid);

        init_bootmem_node(p, paddr >> PAGE_SHIFT, p->node_start_pfn, end_pfn);

        free_bootmem_with_active_regions(nid, end_pfn);

        /*
         * XXX Handle initial reservations for the system memory node
         * only for the moment, we'll refactor this later for handling
         * reservations in other nodes.
         */
        if (nid == 0) {
                struct memblock_region *reg;

                /* Reserve the sections we're already using. */
                for_each_memblock(reserved, reg) {
                        unsigned long size = reg->size;

#ifdef CONFIG_HIGHMEM
                        /* ...but not highmem */
                        if (PFN_DOWN(reg->base) >= highstart_pfn)
                                continue;

                        if (PFN_UP(reg->base + size) > highstart_pfn)
                                size = (highstart_pfn - PFN_DOWN(reg->base))
                                       << PAGE_SHIFT;
#endif

                        reserve_bootmem(reg->base, size, BOOTMEM_DEFAULT);
                }
        }

        sparse_memory_present_with_active_regions(nid);
}

static void __init do_init_bootmem(void)
{
        struct memblock_region *reg;
        int i;

        /* Add active regions with valid PFNs. */
        for_each_memblock(memory, reg) {
                unsigned long start_pfn, end_pfn;
                start_pfn = memblock_region_memory_base_pfn(reg);
                end_pfn = memblock_region_memory_end_pfn(reg);
                memblock_set_node(PFN_PHYS(start_pfn),
                                  PFN_PHYS(end_pfn - start_pfn),
                                  &memblock.memory, 0);
        }

        /* All of system RAM sits in node 0 for the non-NUMA case */
        allocate_pgdat(0);
        node_set_online(0);

        soc_mem_setup();

        for_each_online_node(i)
                bootmem_init_one_node(i);

        sparse_init();
}

extern char _heap_start[];

static void __init init_and_reserve_mem(void)
{
        unsigned long start_pfn, heap_start;
        u64 base = min_low_pfn << PAGE_SHIFT;
        u64 size = (max_low_pfn << PAGE_SHIFT) - base;

        heap_start = (unsigned long) &_heap_start;

        memblock_add(base, size);

        /*
         * Partially used pages are not usable - thus
         * we are rounding upwards:
         */
        start_pfn = PFN_UP(__pa(heap_start));

        /*
         * Reserve the kernel text.
         */
        memblock_reserve(base, (PFN_PHYS(start_pfn) + PAGE_SIZE - 1) - base);

#ifdef CONFIG_HIGHMEM
        /*
         * Add & reserve highmem, so page structures are initialised.
         */
        base = highstart_pfn << PAGE_SHIFT;
        size = (highend_pfn << PAGE_SHIFT) - base;
        if (size) {
                memblock_add(base, size);
                memblock_reserve(base, size);
        }
#endif
}

#ifdef CONFIG_HIGHMEM
/*
 * Ensure we have allocated page tables in swapper_pg_dir for the
 * fixed mappings range from 'start' to 'end'.
 */
static void __init allocate_pgtables(unsigned long start, unsigned long end)
{
        pgd_t *pgd;
        pmd_t *pmd;
        pte_t *pte;
        int i, j;
        unsigned long vaddr;

        vaddr = start;
        i = pgd_index(vaddr);
        j = pmd_index(vaddr);
        pgd = swapper_pg_dir + i;

        for ( ; (i < PTRS_PER_PGD) && (vaddr != end); pgd++, i++) {
                pmd = (pmd_t *)pgd;
                for (; (j < PTRS_PER_PMD) && (vaddr != end); pmd++, j++) {
                        vaddr += PMD_SIZE;

                        if (!pmd_none(*pmd))
                                continue;

                        pte = (pte_t *)alloc_bootmem_low_pages(PAGE_SIZE);
                        pmd_populate_kernel(&init_mm, pmd, pte);
                }
                j = 0;
        }
}

static void __init fixedrange_init(void)
{
        unsigned long vaddr, end;
        pgd_t *pgd;
        pud_t *pud;
        pmd_t *pmd;
        pte_t *pte;

        /*
         * Fixed mappings:
         */
        vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
        end = (FIXADDR_TOP + PMD_SIZE - 1) & PMD_MASK;
        allocate_pgtables(vaddr, end);

        /*
         * Permanent kmaps:
         */
        vaddr = PKMAP_BASE;
        allocate_pgtables(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP);

        pgd = swapper_pg_dir + pgd_index(vaddr);
        pud = pud_offset(pgd, vaddr);
        pmd = pmd_offset(pud, vaddr);
        pte = pte_offset_kernel(pmd, vaddr);
        pkmap_page_table = pte;
}
#endif /* CONFIG_HIGHMEM */

/*
 * paging_init() continues the virtual memory environment setup which
 * was begun by the code in arch/metag/kernel/setup.c.
 */
void __init paging_init(unsigned long mem_end)
{
        unsigned long max_zone_pfns[MAX_NR_ZONES];
        int nid;

        init_and_reserve_mem();

        memblock_allow_resize();

        memblock_dump_all();

        nodes_clear(node_online_map);

        init_new_context(&init_task, &init_mm);

        memset(swapper_pg_dir, 0, sizeof(swapper_pg_dir));

        do_init_bootmem();
        mmu_init(mem_end);

#ifdef CONFIG_HIGHMEM
        fixedrange_init();
        kmap_init();
#endif

        /* Initialize the zero page to a bootmem page, already zeroed. */
        empty_zero_page = (unsigned long)alloc_bootmem_pages(PAGE_SIZE);

        user_gateway_init();

        memset(max_zone_pfns, 0, sizeof(max_zone_pfns));

        for_each_online_node(nid) {
                pg_data_t *pgdat = NODE_DATA(nid);
                unsigned long low, start_pfn;

                start_pfn = pgdat->bdata->node_min_pfn;
                low = pgdat->bdata->node_low_pfn;

                if (max_zone_pfns[ZONE_NORMAL] < low)
                        max_zone_pfns[ZONE_NORMAL] = low;

#ifdef CONFIG_HIGHMEM
                max_zone_pfns[ZONE_HIGHMEM] = highend_pfn;
#endif
                pr_info("Node %u: start_pfn = 0x%lx, low = 0x%lx\n",
                        nid, start_pfn, low);
        }

        free_area_init_nodes(max_zone_pfns);
}

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

        /*
         * Explicitly reset zone->managed_pages because highmem pages are
         * freed before calling free_all_bootmem();
         */
        reset_all_zones_managed_pages();
        for (tmp = highstart_pfn; tmp < highend_pfn; tmp++)
                free_highmem_page(pfn_to_page(tmp));
#endif /* CONFIG_HIGHMEM */

        free_all_bootmem();
        mem_init_print_info(NULL);
}

void free_initmem(void)
{
        free_initmem_default(POISON_FREE_INITMEM);
}

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