/*
 *  PowerPC version
 *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
 *
 *  Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
 *  and Cort Dougan (PReP) (cort@cs.nmt.edu)
 *    Copyright (C) 1996 Paul Mackerras
 *  PPC44x/36-bit changes by Matt Porter (mporter@mvista.com)
 *
 *  Derived from "arch/i386/mm/init.c"
 *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License
 *  as published by the Free Software Foundation; either version
 *  2 of the License, or (at your option) any later version.
 *
 */

#include <linux/module.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/gfp.h>
#include <linux/types.h>
#include <linux/mm.h>
#include <linux/stddef.h>
#include <linux/init.h>
#include <linux/bootmem.h>
#include <linux/highmem.h>
#include <linux/initrd.h>
#include <linux/pagemap.h>
#include <linux/suspend.h>
#include <linux/memblock.h>
#include <linux/hugetlb.h>

#include <asm/pgalloc.h>
#include <asm/prom.h>
#include <asm/io.h>
#include <asm/mmu_context.h>
#include <asm/pgtable.h>
#include <asm/mmu.h>
#include <asm/smp.h>
#include <asm/machdep.h>
#include <asm/btext.h>
#include <asm/tlb.h>
#include <asm/sections.h>
#include <asm/sparsemem.h>
#include <asm/vdso.h>
#include <asm/fixmap.h>
#include <asm/swiotlb.h>

#include "mmu_decl.h"

#ifndef CPU_FTR_COHERENT_ICACHE
#define CPU_FTR_COHERENT_ICACHE 0       /* XXX for now */
#define CPU_FTR_NOEXECUTE       0
#endif

int init_bootmem_done;
int mem_init_done;
phys_addr_t memory_limit;

#ifdef CONFIG_HIGHMEM
pte_t *kmap_pte;
pgprot_t kmap_prot;

EXPORT_SYMBOL(kmap_prot);
EXPORT_SYMBOL(kmap_pte);

static inline pte_t *virt_to_kpte(unsigned long vaddr)
{
        return pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr),
                        vaddr), vaddr), vaddr);
}
#endif

int page_is_ram(unsigned long pfn)
{
#ifndef CONFIG_PPC64    /* XXX for now */
        return pfn < max_pfn;
#else
        unsigned long paddr = (pfn << PAGE_SHIFT);
        struct memblock_region *reg;

        for_each_memblock(memory, reg)
                if (paddr >= reg->base && paddr < (reg->base + reg->size))
                        return 1;
        return 0;
#endif
}

pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
                              unsigned long size, pgprot_t vma_prot)
{
        if (ppc_md.phys_mem_access_prot)
                return ppc_md.phys_mem_access_prot(file, pfn, size, vma_prot);

        if (!page_is_ram(pfn))
                vma_prot = pgprot_noncached(vma_prot);

        return vma_prot;
}
EXPORT_SYMBOL(phys_mem_access_prot);

#ifdef CONFIG_MEMORY_HOTPLUG

#ifdef CONFIG_NUMA
int memory_add_physaddr_to_nid(u64 start)
{
        return hot_add_scn_to_nid(start);
}
#endif

int arch_add_memory(int nid, u64 start, u64 size)
{
        struct pglist_data *pgdata;
        struct zone *zone;
        unsigned long start_pfn = start >> PAGE_SHIFT;
        unsigned long nr_pages = size >> PAGE_SHIFT;

        pgdata = NODE_DATA(nid);

        start = (unsigned long)__va(start);
        create_section_mapping(start, start + size);

        /* this should work for most non-highmem platforms */
        zone = pgdata->node_zones;

        return __add_pages(nid, zone, start_pfn, nr_pages);
}
#endif /* CONFIG_MEMORY_HOTPLUG */

/*
 * walk_memory_resource() needs to make sure there is no holes in a given
 * memory range.  PPC64 does not maintain the memory layout in /proc/iomem.
 * Instead it maintains it in memblock.memory structures.  Walk through the
 * memory regions, find holes and callback for contiguous regions.
 */
int
walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages,
                void *arg, int (*func)(unsigned long, unsigned long, void *))
{
        struct memblock_region *reg;
        unsigned long end_pfn = start_pfn + nr_pages;
        unsigned long tstart, tend;
        int ret = -1;

        for_each_memblock(memory, reg) {
                tstart = max(start_pfn, memblock_region_memory_base_pfn(reg));
                tend = min(end_pfn, memblock_region_memory_end_pfn(reg));
                if (tstart >= tend)
                        continue;
                ret = (*func)(tstart, tend - tstart, arg);
                if (ret)
                        break;
        }
        return ret;
}
EXPORT_SYMBOL_GPL(walk_system_ram_range);

/*
 * Initialize the bootmem system and give it all the memory we
 * have available.  If we are using highmem, we only put the
 * lowmem into the bootmem system.
 */
#ifndef CONFIG_NEED_MULTIPLE_NODES
void __init do_init_bootmem(void)
{
        unsigned long start, bootmap_pages;
        unsigned long total_pages;
        struct memblock_region *reg;
        int boot_mapsize;

        max_low_pfn = max_pfn = memblock_end_of_DRAM() >> PAGE_SHIFT;
        total_pages = (memblock_end_of_DRAM() - memstart_addr) >> PAGE_SHIFT;
#ifdef CONFIG_HIGHMEM
        total_pages = total_lowmem >> PAGE_SHIFT;
        max_low_pfn = lowmem_end_addr >> PAGE_SHIFT;
#endif

        /*
         * Find an area to use for the bootmem bitmap.  Calculate the size of
         * bitmap required as (Total Memory) / PAGE_SIZE / BITS_PER_BYTE.
         * Add 1 additional page in case the address isn't page-aligned.
         */
        bootmap_pages = bootmem_bootmap_pages(total_pages);

        start = memblock_alloc(bootmap_pages << PAGE_SHIFT, PAGE_SIZE);

        min_low_pfn = MEMORY_START >> PAGE_SHIFT;
        boot_mapsize = init_bootmem_node(NODE_DATA(0), start >> PAGE_SHIFT, min_low_pfn, max_low_pfn);

        /* 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);
                add_active_range(0, start_pfn, end_pfn);
        }

        /* Add all physical memory to the bootmem map, mark each area
         * present.
         */
#ifdef CONFIG_HIGHMEM
        free_bootmem_with_active_regions(0, lowmem_end_addr >> PAGE_SHIFT);

        /* reserve the sections we're already using */
        for_each_memblock(reserved, reg) {
                unsigned long top = reg->base + reg->size - 1;
                if (top < lowmem_end_addr)
                        reserve_bootmem(reg->base, reg->size, BOOTMEM_DEFAULT);
                else if (reg->base < lowmem_end_addr) {
                        unsigned long trunc_size = lowmem_end_addr - reg->base;
                        reserve_bootmem(reg->base, trunc_size, BOOTMEM_DEFAULT);
                }
        }
#else
        free_bootmem_with_active_regions(0, max_pfn);

        /* reserve the sections we're already using */
        for_each_memblock(reserved, reg)
                reserve_bootmem(reg->base, reg->size, BOOTMEM_DEFAULT);
#endif
        /* XXX need to clip this if using highmem? */
        sparse_memory_present_with_active_regions(0);

        init_bootmem_done = 1;
}

/* mark pages that don't exist as nosave */
static int __init mark_nonram_nosave(void)
{
        struct memblock_region *reg, *prev = NULL;

        for_each_memblock(memory, reg) {
                if (prev &&
                    memblock_region_memory_end_pfn(prev) < memblock_region_memory_base_pfn(reg))
                        register_nosave_region(memblock_region_memory_end_pfn(prev),
                                               memblock_region_memory_base_pfn(reg));
                prev = reg;
        }
        return 0;
}

/*
 * paging_init() sets up the page tables - in fact we've already done this.
 */
void __init paging_init(void)
{
        unsigned long total_ram = memblock_phys_mem_size();
        phys_addr_t top_of_ram = memblock_end_of_DRAM();
        unsigned long max_zone_pfns[MAX_NR_ZONES];

#ifdef CONFIG_PPC32
        unsigned long v = __fix_to_virt(__end_of_fixed_addresses - 1);
        unsigned long end = __fix_to_virt(FIX_HOLE);

        for (; v < end; v += PAGE_SIZE)
                map_page(v, 0, 0); /* XXX gross */
#endif

#ifdef CONFIG_HIGHMEM
        map_page(PKMAP_BASE, 0, 0);     /* XXX gross */
        pkmap_page_table = virt_to_kpte(PKMAP_BASE);

        kmap_pte = virt_to_kpte(__fix_to_virt(FIX_KMAP_BEGIN));
        kmap_prot = PAGE_KERNEL;
#endif /* CONFIG_HIGHMEM */

        printk(KERN_DEBUG "Top of RAM: 0x%llx, Total RAM: 0x%lx\n",
               (unsigned long long)top_of_ram, total_ram);
        printk(KERN_DEBUG "Memory hole size: %ldMB\n",
               (long int)((top_of_ram - total_ram) >> 20));
        memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
#ifdef CONFIG_HIGHMEM
        max_zone_pfns[ZONE_DMA] = lowmem_end_addr >> PAGE_SHIFT;
        max_zone_pfns[ZONE_HIGHMEM] = top_of_ram >> PAGE_SHIFT;
#else
        max_zone_pfns[ZONE_DMA] = top_of_ram >> PAGE_SHIFT;
#endif
        free_area_init_nodes(max_zone_pfns);

        mark_nonram_nosave();
}
#endif /* ! CONFIG_NEED_MULTIPLE_NODES */

void __init mem_init(void)
{
#ifdef CONFIG_NEED_MULTIPLE_NODES
        int nid;
#endif
        pg_data_t *pgdat;
        unsigned long i;
        struct page *page;
        unsigned long reservedpages = 0, codesize, initsize, datasize, bsssize;

#ifdef CONFIG_SWIOTLB
        if (ppc_swiotlb_enable)
                swiotlb_init(1);
#endif

        num_physpages = memblock_phys_mem_size() >> PAGE_SHIFT;
        high_memory = (void *) __va(max_low_pfn * PAGE_SIZE);

#ifdef CONFIG_NEED_MULTIPLE_NODES
        for_each_online_node(nid) {
                if (NODE_DATA(nid)->node_spanned_pages != 0) {
                        printk("freeing bootmem node %d\n", nid);
                        totalram_pages +=
                                free_all_bootmem_node(NODE_DATA(nid));
                }
        }
#else
        max_mapnr = max_pfn;
        totalram_pages += free_all_bootmem();
#endif
        for_each_online_pgdat(pgdat) {
                for (i = 0; i < pgdat->node_spanned_pages; i++) {
                        if (!pfn_valid(pgdat->node_start_pfn + i))
                                continue;
                        page = pgdat_page_nr(pgdat, i);
                        if (PageReserved(page))
                                reservedpages++;
                }
        }

        codesize = (unsigned long)&_sdata - (unsigned long)&_stext;
        datasize = (unsigned long)&_edata - (unsigned long)&_sdata;
        initsize = (unsigned long)&__init_end - (unsigned long)&__init_begin;
        bsssize = (unsigned long)&__bss_stop - (unsigned long)&__bss_start;

#ifdef CONFIG_HIGHMEM
        {
                unsigned long pfn, highmem_mapnr;

                highmem_mapnr = lowmem_end_addr >> PAGE_SHIFT;
                for (pfn = highmem_mapnr; pfn < max_mapnr; ++pfn) {
                        struct page *page = pfn_to_page(pfn);
                        if (memblock_is_reserved(pfn << PAGE_SHIFT))
                                continue;
                        ClearPageReserved(page);
                        init_page_count(page);
                        __free_page(page);
                        totalhigh_pages++;
                        reservedpages--;
                }
                totalram_pages += totalhigh_pages;
                printk(KERN_DEBUG "High memory: %luk\n",
                       totalhigh_pages << (PAGE_SHIFT-10));
        }
#endif /* CONFIG_HIGHMEM */

        printk(KERN_INFO "Memory: %luk/%luk available (%luk kernel code, "
               "%luk reserved, %luk data, %luk bss, %luk init)\n",
                nr_free_pages() << (PAGE_SHIFT-10),
                num_physpages << (PAGE_SHIFT-10),
                codesize >> 10,
                reservedpages << (PAGE_SHIFT-10),
                datasize >> 10,
                bsssize >> 10,
                initsize >> 10);

#ifdef CONFIG_PPC32
        pr_info("Kernel virtual memory layout:\n");
        pr_info("  * 0x%08lx..0x%08lx  : fixmap\n", FIXADDR_START, FIXADDR_TOP);
#ifdef CONFIG_HIGHMEM
        pr_info("  * 0x%08lx..0x%08lx  : highmem PTEs\n",
                PKMAP_BASE, PKMAP_ADDR(LAST_PKMAP));
#endif /* CONFIG_HIGHMEM */
#ifdef CONFIG_NOT_COHERENT_CACHE
        pr_info("  * 0x%08lx..0x%08lx  : consistent mem\n",
                IOREMAP_TOP, IOREMAP_TOP + CONFIG_CONSISTENT_SIZE);
#endif /* CONFIG_NOT_COHERENT_CACHE */
        pr_info("  * 0x%08lx..0x%08lx  : early ioremap\n",
                ioremap_bot, IOREMAP_TOP);
        pr_info("  * 0x%08lx..0x%08lx  : vmalloc & ioremap\n",
                VMALLOC_START, VMALLOC_END);
#endif /* CONFIG_PPC32 */

        mem_init_done = 1;
}

/*
 * This is called when a page has been modified by the kernel.
 * It just marks the page as not i-cache clean.  We do the i-cache
 * flush later when the page is given to a user process, if necessary.
 */
void flush_dcache_page(struct page *page)
{
        if (cpu_has_feature(CPU_FTR_COHERENT_ICACHE))
                return;
        /* avoid an atomic op if possible */
        if (test_bit(PG_arch_1, &page->flags))
                clear_bit(PG_arch_1, &page->flags);
}
EXPORT_SYMBOL(flush_dcache_page);

void flush_dcache_icache_page(struct page *page)
{
#ifdef CONFIG_HUGETLB_PAGE
        if (PageCompound(page)) {
                flush_dcache_icache_hugepage(page);
                return;
        }
#endif
#ifdef CONFIG_BOOKE
        {
                void *start = kmap_atomic(page, KM_PPC_SYNC_ICACHE);
                __flush_dcache_icache(start);
                kunmap_atomic(start, KM_PPC_SYNC_ICACHE);
        }
#elif defined(CONFIG_8xx) || defined(CONFIG_PPC64)
        /* On 8xx there is no need to kmap since highmem is not supported */
        __flush_dcache_icache(page_address(page)); 
#else
        __flush_dcache_icache_phys(page_to_pfn(page) << PAGE_SHIFT);
#endif
}

void clear_user_page(void *page, unsigned long vaddr, struct page *pg)
{
        clear_page(page);

        /*
         * We shouldnt have to do this, but some versions of glibc
         * require it (ld.so assumes zero filled pages are icache clean)
         * - Anton
         */
        flush_dcache_page(pg);
}
EXPORT_SYMBOL(clear_user_page);

void copy_user_page(void *vto, void *vfrom, unsigned long vaddr,
                    struct page *pg)
{
        copy_page(vto, vfrom);

        /*
         * We should be able to use the following optimisation, however
         * there are two problems.
         * Firstly a bug in some versions of binutils meant PLT sections
         * were not marked executable.
         * Secondly the first word in the GOT section is blrl, used
         * to establish the GOT address. Until recently the GOT was
         * not marked executable.
         * - Anton
         */
#if 0
        if (!vma->vm_file && ((vma->vm_flags & VM_EXEC) == 0))
                return;
#endif

        flush_dcache_page(pg);
}

void flush_icache_user_range(struct vm_area_struct *vma, struct page *page,
                             unsigned long addr, int len)
{
        unsigned long maddr;

        maddr = (unsigned long) kmap(page) + (addr & ~PAGE_MASK);
        flush_icache_range(maddr, maddr + len);
        kunmap(page);
}
EXPORT_SYMBOL(flush_icache_user_range);

/*
 * This is called at the end of handling a user page fault, when the
 * fault has been handled by updating a PTE in the linux page tables.
 * We use it to preload an HPTE into the hash table corresponding to
 * the updated linux PTE.
 * 
 * This must always be called with the pte lock held.
 */
void update_mmu_cache(struct vm_area_struct *vma, unsigned long address,
                      pte_t *ptep)
{
#ifdef CONFIG_PPC_STD_MMU
        unsigned long access = 0, trap;

        /* We only want HPTEs for linux PTEs that have _PAGE_ACCESSED set */
        if (!pte_young(*ptep) || address >= TASK_SIZE)
                return;

        /* We try to figure out if we are coming from an instruction
         * access fault and pass that down to __hash_page so we avoid
         * double-faulting on execution of fresh text. We have to test
         * for regs NULL since init will get here first thing at boot
         *
         * We also avoid filling the hash if not coming from a fault
         */
        if (current->thread.regs == NULL)
                return;
        trap = TRAP(current->thread.regs);
        if (trap == 0x400)
                access |= _PAGE_EXEC;
        else if (trap != 0x300)
                return;
        hash_preload(vma->vm_mm, address, access, trap);
#endif /* CONFIG_PPC_STD_MMU */
}