/*
 *  S390 version
 *    Copyright IBM Corp. 1999
 *    Author(s): Hartmut Penner (hp@de.ibm.com)
 *
 *  Derived from "arch/i386/mm/init.c"
 *    Copyright (C) 1995  Linus Torvalds
 */

#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/ptrace.h>
#include <linux/mman.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/smp.h>
#include <linux/init.h>
#include <linux/pagemap.h>
#include <linux/bootmem.h>
#include <linux/memory.h>
#include <linux/pfn.h>
#include <linux/poison.h>
#include <linux/initrd.h>
#include <linux/export.h>
#include <linux/gfp.h>
#include <asm/processor.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/dma.h>
#include <asm/lowcore.h>
#include <asm/tlb.h>
#include <asm/tlbflush.h>
#include <asm/sections.h>
#include <asm/ctl_reg.h>
#include <asm/sclp.h>

pgd_t swapper_pg_dir[PTRS_PER_PGD] __attribute__((__aligned__(PAGE_SIZE)));

unsigned long empty_zero_page, zero_page_mask;
EXPORT_SYMBOL(empty_zero_page);
EXPORT_SYMBOL(zero_page_mask);

static void __init setup_zero_pages(void)
{
        struct cpuid cpu_id;
        unsigned int order;
        struct page *page;
        int i;

        get_cpu_id(&cpu_id);
        switch (cpu_id.machine) {
        case 0x9672:    /* g5 */
        case 0x2064:    /* z900 */
        case 0x2066:    /* z900 */
        case 0x2084:    /* z990 */
        case 0x2086:    /* z990 */
        case 0x2094:    /* z9-109 */
        case 0x2096:    /* z9-109 */
                order = 0;
                break;
        case 0x2097:    /* z10 */
        case 0x2098:    /* z10 */
        case 0x2817:    /* z196 */
        case 0x2818:    /* z196 */
                order = 2;
                break;
        case 0x2827:    /* zEC12 */
        case 0x2828:    /* zEC12 */
        default:
                order = 5;
                break;
        }
        /* Limit number of empty zero pages for small memory sizes */
        if (order > 2 && totalram_pages <= 16384)
                order = 2;

        empty_zero_page = __get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
        if (!empty_zero_page)
                panic("Out of memory in setup_zero_pages");

        page = virt_to_page((void *) empty_zero_page);
        split_page(page, order);
        for (i = 1 << order; i > 0; i--) {
                mark_page_reserved(page);
                page++;
        }

        zero_page_mask = ((PAGE_SIZE << order) - 1) & PAGE_MASK;
}

/*
 * paging_init() sets up the page tables
 */
void __init paging_init(void)
{
        unsigned long max_zone_pfns[MAX_NR_ZONES];
        unsigned long pgd_type, asce_bits;

        init_mm.pgd = swapper_pg_dir;
#ifdef CONFIG_64BIT
        if (VMALLOC_END > (1UL << 42)) {
                asce_bits = _ASCE_TYPE_REGION2 | _ASCE_TABLE_LENGTH;
                pgd_type = _REGION2_ENTRY_EMPTY;
        } else {
                asce_bits = _ASCE_TYPE_REGION3 | _ASCE_TABLE_LENGTH;
                pgd_type = _REGION3_ENTRY_EMPTY;
        }
#else
        asce_bits = _ASCE_TABLE_LENGTH;
        pgd_type = _SEGMENT_ENTRY_EMPTY;
#endif
        S390_lowcore.kernel_asce = (__pa(init_mm.pgd) & PAGE_MASK) | asce_bits;
        clear_table((unsigned long *) init_mm.pgd, pgd_type,
                    sizeof(unsigned long)*2048);
        vmem_map_init();

        /* enable virtual mapping in kernel mode */
        __ctl_load(S390_lowcore.kernel_asce, 1, 1);
        __ctl_load(S390_lowcore.kernel_asce, 7, 7);
        __ctl_load(S390_lowcore.kernel_asce, 13, 13);
        arch_local_irq_restore(4UL << (BITS_PER_LONG - 8));

        sparse_memory_present_with_active_regions(MAX_NUMNODES);
        sparse_init();
        memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
        max_zone_pfns[ZONE_DMA] = PFN_DOWN(MAX_DMA_ADDRESS);
        max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
        free_area_init_nodes(max_zone_pfns);
}

void __init mem_init(void)
{
        if (MACHINE_HAS_TLB_LC)
                cpumask_set_cpu(0, &init_mm.context.cpu_attach_mask);
        cpumask_set_cpu(0, mm_cpumask(&init_mm));
        atomic_set(&init_mm.context.attach_count, 1);

        max_mapnr = max_low_pfn;
        high_memory = (void *) __va(max_low_pfn * PAGE_SIZE);

        /* Setup guest page hinting */
        cmma_init();

        /* this will put all low memory onto the freelists */
        free_all_bootmem();
        setup_zero_pages();     /* Setup zeroed pages. */

        mem_init_print_info(NULL);
        printk("Write protected kernel read-only data: %#lx - %#lx\n",
               (unsigned long)&_stext,
               PFN_ALIGN((unsigned long)&_eshared) - 1);
}

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

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

#ifdef CONFIG_MEMORY_HOTPLUG
int arch_add_memory(int nid, u64 start, u64 size)
{
        unsigned long zone_start_pfn, zone_end_pfn, nr_pages;
        unsigned long start_pfn = PFN_DOWN(start);
        unsigned long size_pages = PFN_DOWN(size);
        struct zone *zone;
        int rc;

        rc = vmem_add_mapping(start, size);
        if (rc)
                return rc;
        for_each_zone(zone) {
                if (zone_idx(zone) != ZONE_MOVABLE) {
                        /* Add range within existing zone limits */
                        zone_start_pfn = zone->zone_start_pfn;
                        zone_end_pfn = zone->zone_start_pfn +
                                       zone->spanned_pages;
                } else {
                        /* Add remaining range to ZONE_MOVABLE */
                        zone_start_pfn = start_pfn;
                        zone_end_pfn = start_pfn + size_pages;
                }
                if (start_pfn < zone_start_pfn || start_pfn >= zone_end_pfn)
                        continue;
                nr_pages = (start_pfn + size_pages > zone_end_pfn) ?
                           zone_end_pfn - start_pfn : size_pages;
                rc = __add_pages(nid, zone, start_pfn, nr_pages);
                if (rc)
                        break;
                start_pfn += nr_pages;
                size_pages -= nr_pages;
                if (!size_pages)
                        break;
        }
        if (rc)
                vmem_remove_mapping(start, size);
        return rc;
}

unsigned long memory_block_size_bytes(void)
{
        /*
         * Make sure the memory block size is always greater
         * or equal than the memory increment size.
         */
        return max_t(unsigned long, MIN_MEMORY_BLOCK_SIZE, sclp_get_rzm());
}

#ifdef CONFIG_MEMORY_HOTREMOVE
int arch_remove_memory(u64 start, u64 size)
{
        /*
         * There is no hardware or firmware interface which could trigger a
         * hot memory remove on s390. So there is nothing that needs to be
         * implemented.
         */
        return -EBUSY;
}
#endif
#endif /* CONFIG_MEMORY_HOTPLUG */