/*
 *  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
 *  Amiga/APUS changes by Jesper Skov (jskov@cygnus.co.uk).
 *  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/config.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.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 <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/bootinfo.h>

#include "mem_pieces.h"
#include "mmu_decl.h"

#if defined(CONFIG_KERNEL_START_BOOL) || defined(CONFIG_LOWMEM_SIZE_BOOL)
/* The ammount of lowmem must be within 0xF0000000 - KERNELBASE. */
#if (CONFIG_LOWMEM_SIZE > (0xF0000000 - KERNELBASE))
#error "You must adjust CONFIG_LOWMEM_SIZE or CONFIG_START_KERNEL"
#endif
#endif
#define MAX_LOW_MEM     CONFIG_LOWMEM_SIZE

DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);

unsigned long total_memory;
unsigned long total_lowmem;

unsigned long ppc_memstart;
unsigned long ppc_memoffset = PAGE_OFFSET;

int mem_init_done;
int init_bootmem_done;
int boot_mapsize;
#ifdef CONFIG_PPC_PMAC
unsigned long agp_special_page;
#endif

extern char _end[];
extern char etext[], _stext[];
extern char __init_begin, __init_end;
extern char __prep_begin, __prep_end;
extern char __chrp_begin, __chrp_end;
extern char __pmac_begin, __pmac_end;
extern char __openfirmware_begin, __openfirmware_end;

#ifdef CONFIG_HIGHMEM
pte_t *kmap_pte;
pgprot_t kmap_prot;

EXPORT_SYMBOL(kmap_prot);
EXPORT_SYMBOL(kmap_pte);
#endif

void MMU_init(void);
void set_phys_avail(unsigned long total_ram);

/* XXX should be in current.h  -- paulus */
extern struct task_struct *current_set[NR_CPUS];

char *klimit = _end;
struct mem_pieces phys_avail;

extern char *sysmap;
extern unsigned long sysmap_size;

/*
 * this tells the system to map all of ram with the segregs
 * (i.e. page tables) instead of the bats.
 * -- Cort
 */
int __map_without_bats;
int __map_without_ltlbs;

/* max amount of RAM to use */
unsigned long __max_memory;
/* max amount of low RAM to map in */
unsigned long __max_low_memory = MAX_LOW_MEM;

void show_mem(void)
{
        int i,free = 0,total = 0,reserved = 0;
        int shared = 0, cached = 0;
        int highmem = 0;

        printk("Mem-info:\n");
        show_free_areas();
        printk("Free swap:       %6ldkB\n", nr_swap_pages<<(PAGE_SHIFT-10));
        i = max_mapnr;
        while (i-- > 0) {
                total++;
                if (PageHighMem(mem_map+i))
                        highmem++;
                if (PageReserved(mem_map+i))
                        reserved++;
                else if (PageSwapCache(mem_map+i))
                        cached++;
                else if (!page_count(mem_map+i))
                        free++;
                else
                        shared += page_count(mem_map+i) - 1;
        }
        printk("%d pages of RAM\n",total);
        printk("%d pages of HIGHMEM\n", highmem);
        printk("%d free pages\n",free);
        printk("%d reserved pages\n",reserved);
        printk("%d pages shared\n",shared);
        printk("%d pages swap cached\n",cached);
}

/* Free up now-unused memory */
static void free_sec(unsigned long start, unsigned long end, const char *name)
{
        unsigned long cnt = 0;

        while (start < end) {
                ClearPageReserved(virt_to_page(start));
                set_page_count(virt_to_page(start), 1);
                free_page(start);
                cnt++;
                start += PAGE_SIZE;
        }
        if (cnt) {
                printk(" %ldk %s", cnt << (PAGE_SHIFT - 10), name);
                totalram_pages += cnt;
        }
}

void free_initmem(void)
{
#define FREESEC(TYPE) \
        free_sec((unsigned long)(&__ ## TYPE ## _begin), \
                 (unsigned long)(&__ ## TYPE ## _end), \
                 #TYPE);

        printk ("Freeing unused kernel memory:");
        FREESEC(init);
        if (_machine != _MACH_Pmac)
                FREESEC(pmac);
        if (_machine != _MACH_chrp)
                FREESEC(chrp);
        if (_machine != _MACH_prep)
                FREESEC(prep);
        if (!have_of)
                FREESEC(openfirmware);
        printk("\n");
#undef FREESEC
}

#ifdef CONFIG_BLK_DEV_INITRD
void free_initrd_mem(unsigned long start, unsigned long end)
{
        printk ("Freeing initrd memory: %ldk freed\n", (end - start) >> 10);

        for (; start < end; start += PAGE_SIZE) {
                ClearPageReserved(virt_to_page(start));
                set_page_count(virt_to_page(start), 1);
                free_page(start);
                totalram_pages++;
        }
}
#endif

/*
 * Check for command-line options that affect what MMU_init will do.
 */
void MMU_setup(void)
{
        /* Check for nobats option (used in mapin_ram). */
        if (strstr(cmd_line, "nobats")) {
                __map_without_bats = 1;
        }

        if (strstr(cmd_line, "noltlbs")) {
                __map_without_ltlbs = 1;
        }

        /* Look for mem= option on command line */
        if (strstr(cmd_line, "mem=")) {
                char *p, *q;
                unsigned long maxmem = 0;

                for (q = cmd_line; (p = strstr(q, "mem=")) != 0; ) {
                        q = p + 4;
                        if (p > cmd_line && p[-1] != ' ')
                                continue;
                        maxmem = simple_strtoul(q, &q, 0);
                        if (*q == 'k' || *q == 'K') {
                                maxmem <<= 10;
                                ++q;
                        } else if (*q == 'm' || *q == 'M') {
                                maxmem <<= 20;
                                ++q;
                        }
                }
                __max_memory = maxmem;
        }
}

/*
 * MMU_init sets up the basic memory mappings for the kernel,
 * including both RAM and possibly some I/O regions,
 * and sets up the page tables and the MMU hardware ready to go.
 */
void __init MMU_init(void)
{
        if (ppc_md.progress)
                ppc_md.progress("MMU:enter", 0x111);

        /* parse args from command line */
        MMU_setup();

        /*
         * Figure out how much memory we have, how much
         * is lowmem, and how much is highmem.  If we were
         * passed the total memory size from the bootloader,
         * just use it.
         */
        if (boot_mem_size)
                total_memory = boot_mem_size;
        else
                total_memory = ppc_md.find_end_of_memory();

        if (__max_memory && total_memory > __max_memory)
                total_memory = __max_memory;
        total_lowmem = total_memory;
#ifdef CONFIG_FSL_BOOKE
        /* Freescale Book-E parts expect lowmem to be mapped by fixed TLB
         * entries, so we need to adjust lowmem to match the amount we can map
         * in the fixed entries */
        adjust_total_lowmem();
#endif /* CONFIG_FSL_BOOKE */
        if (total_lowmem > __max_low_memory) {
                total_lowmem = __max_low_memory;
#ifndef CONFIG_HIGHMEM
                total_memory = total_lowmem;
#endif /* CONFIG_HIGHMEM */
        }
        set_phys_avail(total_lowmem);

        /* Initialize the MMU hardware */
        if (ppc_md.progress)
                ppc_md.progress("MMU:hw init", 0x300);
        MMU_init_hw();

        /* Map in all of RAM starting at KERNELBASE */
        if (ppc_md.progress)
                ppc_md.progress("MMU:mapin", 0x301);
        mapin_ram();

#ifdef CONFIG_HIGHMEM
        ioremap_base = PKMAP_BASE;
#else
        ioremap_base = 0xfe000000UL;    /* for now, could be 0xfffff000 */
#endif /* CONFIG_HIGHMEM */
        ioremap_bot = ioremap_base;

        /* Map in I/O resources */
        if (ppc_md.progress)
                ppc_md.progress("MMU:setio", 0x302);
        if (ppc_md.setup_io_mappings)
                ppc_md.setup_io_mappings();

        /* Initialize the context management stuff */
        mmu_context_init();

        if (ppc_md.progress)
                ppc_md.progress("MMU:exit", 0x211);

#ifdef CONFIG_BOOTX_TEXT
        /* By default, we are no longer mapped */
        boot_text_mapped = 0;
        /* Must be done last, or ppc_md.progress will die. */
        map_boot_text();
#endif
}

/* This is only called until mem_init is done. */
void __init *early_get_page(void)
{
        void *p;

        if (init_bootmem_done) {
                p = alloc_bootmem_pages(PAGE_SIZE);
        } else {
                p = mem_pieces_find(PAGE_SIZE, PAGE_SIZE);
        }
        return p;
}

/*
 * Initialize the bootmem system and give it all the memory we
 * have available.
 */
void __init do_init_bootmem(void)
{
        unsigned long start, size;
        int i;

        /*
         * Find an area to use for the bootmem bitmap.
         * We look for the first area which is at least
         * 128kB in length (128kB is enough for a bitmap
         * for 4GB of memory, using 4kB pages), plus 1 page
         * (in case the address isn't page-aligned).
         */
        start = 0;
        size = 0;
        for (i = 0; i < phys_avail.n_regions; ++i) {
                unsigned long a = phys_avail.regions[i].address;
                unsigned long s = phys_avail.regions[i].size;
                if (s <= size)
                        continue;
                start = a;
                size = s;
                if (s >= 33 * PAGE_SIZE)
                        break;
        }
        start = PAGE_ALIGN(start);

        min_low_pfn = start >> PAGE_SHIFT;
        max_low_pfn = (PPC_MEMSTART + total_lowmem) >> PAGE_SHIFT;
        max_pfn = (PPC_MEMSTART + total_memory) >> PAGE_SHIFT;
        boot_mapsize = init_bootmem_node(&contig_page_data, min_low_pfn,
                                         PPC_MEMSTART >> PAGE_SHIFT,
                                         max_low_pfn);

        /* remove the bootmem bitmap from the available memory */
        mem_pieces_remove(&phys_avail, start, boot_mapsize, 1);

        /* add everything in phys_avail into the bootmem map */
        for (i = 0; i < phys_avail.n_regions; ++i)
                free_bootmem(phys_avail.regions[i].address,
                             phys_avail.regions[i].size);

        init_bootmem_done = 1;
}

/*
 * paging_init() sets up the page tables - in fact we've already done this.
 */
void __init paging_init(void)
{
        unsigned long zones_size[MAX_NR_ZONES], i;

#ifdef CONFIG_HIGHMEM
        map_page(PKMAP_BASE, 0, 0);     /* XXX gross */
        pkmap_page_table = pte_offset_kernel(pmd_offset(pgd_offset_k
                        (PKMAP_BASE), PKMAP_BASE), PKMAP_BASE);
        map_page(KMAP_FIX_BEGIN, 0, 0); /* XXX gross */
        kmap_pte = pte_offset_kernel(pmd_offset(pgd_offset_k
                        (KMAP_FIX_BEGIN), KMAP_FIX_BEGIN), KMAP_FIX_BEGIN);
        kmap_prot = PAGE_KERNEL;
#endif /* CONFIG_HIGHMEM */

        /*
         * All pages are DMA-able so we put them all in the DMA zone.
         */
        zones_size[ZONE_DMA] = total_lowmem >> PAGE_SHIFT;
        for (i = 1; i < MAX_NR_ZONES; i++)
                zones_size[i] = 0;

#ifdef CONFIG_HIGHMEM
        zones_size[ZONE_HIGHMEM] = (total_memory - total_lowmem) >> PAGE_SHIFT;
#endif /* CONFIG_HIGHMEM */

        free_area_init(zones_size);
}

void __init mem_init(void)
{
        unsigned long addr;
        int codepages = 0;
        int datapages = 0;
        int initpages = 0;
#ifdef CONFIG_HIGHMEM
        unsigned long highmem_mapnr;

        highmem_mapnr = total_lowmem >> PAGE_SHIFT;
#endif /* CONFIG_HIGHMEM */
        max_mapnr = total_memory >> PAGE_SHIFT;

        high_memory = (void *) __va(PPC_MEMSTART + total_lowmem);
        num_physpages = max_mapnr;      /* RAM is assumed contiguous */

        totalram_pages += free_all_bootmem();

#ifdef CONFIG_BLK_DEV_INITRD
        /* if we are booted from BootX with an initial ramdisk,
           make sure the ramdisk pages aren't reserved. */
        if (initrd_start) {
                for (addr = initrd_start; addr < initrd_end; addr += PAGE_SIZE)
                        ClearPageReserved(virt_to_page(addr));
        }
#endif /* CONFIG_BLK_DEV_INITRD */

#ifdef CONFIG_PPC_OF
        /* mark the RTAS pages as reserved */
        if ( rtas_data )
                for (addr = (ulong)__va(rtas_data);
                     addr < PAGE_ALIGN((ulong)__va(rtas_data)+rtas_size) ;
                     addr += PAGE_SIZE)
                        SetPageReserved(virt_to_page(addr));
#endif
#ifdef CONFIG_PPC_PMAC
        if (agp_special_page)
                SetPageReserved(virt_to_page(agp_special_page));
#endif
        if ( sysmap )
                for (addr = (unsigned long)sysmap;
                     addr < PAGE_ALIGN((unsigned long)sysmap+sysmap_size) ;
                     addr += PAGE_SIZE)
                        SetPageReserved(virt_to_page(addr));

        for (addr = PAGE_OFFSET; addr < (unsigned long)high_memory;
             addr += PAGE_SIZE) {
                if (!PageReserved(virt_to_page(addr)))
                        continue;
                if (addr < (ulong) etext)
                        codepages++;
                else if (addr >= (unsigned long)&__init_begin
                         && addr < (unsigned long)&__init_end)
                        initpages++;
                else if (addr < (ulong) klimit)
                        datapages++;
        }

#ifdef CONFIG_HIGHMEM
        {
                unsigned long pfn;

                for (pfn = highmem_mapnr; pfn < max_mapnr; ++pfn) {
                        struct page *page = mem_map + pfn;

                        ClearPageReserved(page);
                        set_bit(PG_highmem, &page->flags);
                        set_page_count(page, 1);
                        __free_page(page);
                        totalhigh_pages++;
                }
                totalram_pages += totalhigh_pages;
        }
#endif /* CONFIG_HIGHMEM */

        printk("Memory: %luk available (%dk kernel code, %dk data, %dk init, %ldk highmem)\n",
               (unsigned long)nr_free_pages()<< (PAGE_SHIFT-10),
               codepages<< (PAGE_SHIFT-10), datapages<< (PAGE_SHIFT-10),
               initpages<< (PAGE_SHIFT-10),
               (unsigned long) (totalhigh_pages << (PAGE_SHIFT-10)));
        if (sysmap)
                printk("System.map loaded at 0x%08x for debugger, size: %ld bytes\n",
                        (unsigned int)sysmap, sysmap_size);
#ifdef CONFIG_PPC_PMAC
        if (agp_special_page)
                printk(KERN_INFO "AGP special page: 0x%08lx\n", agp_special_page);
#endif

        /* Make sure all our pagetable pages have page->mapping
           and page->index set correctly. */
        for (addr = KERNELBASE; addr != 0; addr += PGDIR_SIZE) {
                struct page *pg;
                pmd_t *pmd = pmd_offset(pgd_offset_k(addr), addr);
                if (pmd_present(*pmd)) {
                        pg = pmd_page(*pmd);
                        pg->mapping = (void *) &init_mm;
                        pg->index = addr;
                }
        }

        mem_init_done = 1;
}

/*
 * Set phys_avail to the amount of physical memory,
 * less the kernel text/data/bss.
 */
void __init
set_phys_avail(unsigned long total_memory)
{
        unsigned long kstart, ksize;

        /*
         * Initially, available physical memory is equivalent to all
         * physical memory.
         */

        phys_avail.regions[0].address = PPC_MEMSTART;
        phys_avail.regions[0].size = total_memory;
        phys_avail.n_regions = 1;

        /*
         * Map out the kernel text/data/bss from the available physical
         * memory.
         */

        kstart = __pa(_stext);  /* should be 0 */
        ksize = PAGE_ALIGN(klimit - _stext);

        mem_pieces_remove(&phys_avail, kstart, ksize, 0);
        mem_pieces_remove(&phys_avail, 0, 0x4000, 0);

#if defined(CONFIG_BLK_DEV_INITRD)
        /* Remove the init RAM disk from the available memory. */
        if (initrd_start) {
                mem_pieces_remove(&phys_avail, __pa(initrd_start),
                                  initrd_end - initrd_start, 1);
        }
#endif /* CONFIG_BLK_DEV_INITRD */
#ifdef CONFIG_PPC_OF
        /* remove the RTAS pages from the available memory */
        if (rtas_data)
                mem_pieces_remove(&phys_avail, rtas_data, rtas_size, 1);
#endif
        /* remove the sysmap pages from the available memory */
        if (sysmap)
                mem_pieces_remove(&phys_avail, __pa(sysmap), sysmap_size, 1);
#ifdef CONFIG_PPC_PMAC
        /* Because of some uninorth weirdness, we need a page of
         * memory as high as possible (it must be outside of the
         * bus address seen as the AGP aperture). It will be used
         * by the r128 DRM driver
         *
         * FIXME: We need to make sure that page doesn't overlap any of the\
         * above. This could be done by improving mem_pieces_find to be able
         * to do a backward search from the end of the list.
         */
        if (_machine == _MACH_Pmac && find_devices("uni-north-agp")) {
                agp_special_page = (total_memory - PAGE_SIZE);
                mem_pieces_remove(&phys_avail, agp_special_page, PAGE_SIZE, 0);
                agp_special_page = (unsigned long)__va(agp_special_page);
        }
#endif /* CONFIG_PPC_PMAC */
}

/* Mark some memory as reserved by removing it from phys_avail. */
void __init reserve_phys_mem(unsigned long start, unsigned long size)
{
        mem_pieces_remove(&phys_avail, start, size, 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)
{
        clear_bit(PG_arch_1, &page->flags);
}

void flush_dcache_icache_page(struct page *page)
{
#ifdef CONFIG_BOOKE
        __flush_dcache_icache(kmap(page));
        kunmap(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);
        clear_bit(PG_arch_1, &pg->flags);
}

void copy_user_page(void *vto, void *vfrom, unsigned long vaddr,
                    struct page *pg)
{
        copy_page(vto, vfrom);
        clear_bit(PG_arch_1, &pg->flags);
}

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);
}

/*
 * 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.
 */
void update_mmu_cache(struct vm_area_struct *vma, unsigned long address,
                      pte_t pte)
{
        /* handle i-cache coherency */
        unsigned long pfn = pte_pfn(pte);

        if (pfn_valid(pfn)) {
                struct page *page = pfn_to_page(pfn);
                if (!PageReserved(page)
                    && !test_bit(PG_arch_1, &page->flags)) {
                        if (vma->vm_mm == current->active_mm)
                                __flush_dcache_icache((void *) address);
                        else
                                flush_dcache_icache_page(page);
                        set_bit(PG_arch_1, &page->flags);
                }
        }

#ifdef CONFIG_PPC_STD_MMU
        /* We only want HPTEs for linux PTEs that have _PAGE_ACCESSED set */
        if (Hash != 0 && pte_young(pte)) {
                struct mm_struct *mm;
                pmd_t *pmd;

                mm = (address < TASK_SIZE)? vma->vm_mm: &init_mm;
                pmd = pmd_offset(pgd_offset(mm, address), address);
                if (!pmd_none(*pmd))
                        add_hash_page(mm->context, address, pmd_val(*pmd));
        }
#endif
}