/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 1994 - 2000 Ralf Baechle
 * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
 * Kevin D. Kissell, kevink@mips.com and Carsten Langgaard, carstenl@mips.com
 * Copyright (C) 2000 MIPS Technologies, Inc.  All rights reserved.
 */
#include <linux/bug.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/smp.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/pagemap.h>
#include <linux/ptrace.h>
#include <linux/mman.h>
#include <linux/mm.h>
#include <linux/bootmem.h>
#include <linux/highmem.h>
#include <linux/swap.h>
#include <linux/proc_fs.h>
#include <linux/pfn.h>
#include <linux/hardirq.h>
#include <linux/gfp.h>
#include <linux/kcore.h>

#include <asm/asm-offsets.h>
#include <asm/bootinfo.h>
#include <asm/cachectl.h>
#include <asm/cpu.h>
#include <asm/dma.h>
#include <asm/kmap_types.h>
#include <asm/maar.h>
#include <asm/mmu_context.h>
#include <asm/sections.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/tlb.h>
#include <asm/fixmap.h>
#include <asm/maar.h>

/*
 * We have up to 8 empty zeroed pages so we can map one of the right colour
 * when needed.  This is necessary only on R4000 / R4400 SC and MC versions
 * where we have to avoid VCED / VECI exceptions for good performance at
 * any price.  Since page is never written to after the initialization we
 * don't have to care about aliases on other CPUs.
 */
unsigned long empty_zero_page, zero_page_mask;
EXPORT_SYMBOL_GPL(empty_zero_page);
EXPORT_SYMBOL(zero_page_mask);

/*
 * Not static inline because used by IP27 special magic initialization code
 */
void setup_zero_pages(void)
{
        unsigned int order, i;
        struct page *page;

        if (cpu_has_vce)
                order = 3;
        else
                order = 0;

        empty_zero_page = __get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
        if (!empty_zero_page)
                panic("Oh boy, that early out of memory?");

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

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

static void *__kmap_pgprot(struct page *page, unsigned long addr, pgprot_t prot)
{
        enum fixed_addresses idx;
        unsigned long vaddr, flags, entrylo;
        unsigned long old_ctx;
        pte_t pte;
        int tlbidx;

        BUG_ON(Page_dcache_dirty(page));

        preempt_disable();
        pagefault_disable();
        idx = (addr >> PAGE_SHIFT) & (FIX_N_COLOURS - 1);
        idx += in_interrupt() ? FIX_N_COLOURS : 0;
        vaddr = __fix_to_virt(FIX_CMAP_END - idx);
        pte = mk_pte(page, prot);
#if defined(CONFIG_PHYS_ADDR_T_64BIT) && defined(CONFIG_CPU_MIPS32)
        entrylo = pte_to_entrylo(pte.pte_high);
#else
        entrylo = pte_to_entrylo(pte_val(pte));
#endif

        local_irq_save(flags);
        old_ctx = read_c0_entryhi();
        write_c0_entryhi(vaddr & (PAGE_MASK << 1));
        write_c0_entrylo0(entrylo);
        write_c0_entrylo1(entrylo);
#ifdef CONFIG_XPA
        entrylo = (pte.pte_low & _PFNX_MASK);
        writex_c0_entrylo0(entrylo);
        writex_c0_entrylo1(entrylo);
#endif
        tlbidx = read_c0_wired();
        write_c0_wired(tlbidx + 1);
        write_c0_index(tlbidx);
        mtc0_tlbw_hazard();
        tlb_write_indexed();
        tlbw_use_hazard();
        write_c0_entryhi(old_ctx);
        local_irq_restore(flags);

        return (void*) vaddr;
}

void *kmap_coherent(struct page *page, unsigned long addr)
{
        return __kmap_pgprot(page, addr, PAGE_KERNEL);
}

void *kmap_noncoherent(struct page *page, unsigned long addr)
{
        return __kmap_pgprot(page, addr, PAGE_KERNEL_NC);
}

void kunmap_coherent(void)
{
        unsigned int wired;
        unsigned long flags, old_ctx;

        local_irq_save(flags);
        old_ctx = read_c0_entryhi();
        wired = read_c0_wired() - 1;
        write_c0_wired(wired);
        write_c0_index(wired);
        write_c0_entryhi(UNIQUE_ENTRYHI(wired));
        write_c0_entrylo0(0);
        write_c0_entrylo1(0);
        mtc0_tlbw_hazard();
        tlb_write_indexed();
        tlbw_use_hazard();
        write_c0_entryhi(old_ctx);
        local_irq_restore(flags);
        pagefault_enable();
        preempt_enable();
}

void copy_user_highpage(struct page *to, struct page *from,
        unsigned long vaddr, struct vm_area_struct *vma)
{
        void *vfrom, *vto;

        vto = kmap_atomic(to);
        if (cpu_has_dc_aliases &&
            page_mapcount(from) && !Page_dcache_dirty(from)) {
                vfrom = kmap_coherent(from, vaddr);
                copy_page(vto, vfrom);
                kunmap_coherent();
        } else {
                vfrom = kmap_atomic(from);
                copy_page(vto, vfrom);
                kunmap_atomic(vfrom);
        }
        if ((!cpu_has_ic_fills_f_dc) ||
            pages_do_alias((unsigned long)vto, vaddr & PAGE_MASK))
                flush_data_cache_page((unsigned long)vto);
        kunmap_atomic(vto);
        /* Make sure this page is cleared on other CPU's too before using it */
        smp_wmb();
}

void copy_to_user_page(struct vm_area_struct *vma,
        struct page *page, unsigned long vaddr, void *dst, const void *src,
        unsigned long len)
{
        if (cpu_has_dc_aliases &&
            page_mapcount(page) && !Page_dcache_dirty(page)) {
                void *vto = kmap_coherent(page, vaddr) + (vaddr & ~PAGE_MASK);
                memcpy(vto, src, len);
                kunmap_coherent();
        } else {
                memcpy(dst, src, len);
                if (cpu_has_dc_aliases)
                        SetPageDcacheDirty(page);
        }
        if ((vma->vm_flags & VM_EXEC) && !cpu_has_ic_fills_f_dc)
                flush_cache_page(vma, vaddr, page_to_pfn(page));
}

void copy_from_user_page(struct vm_area_struct *vma,
        struct page *page, unsigned long vaddr, void *dst, const void *src,
        unsigned long len)
{
        if (cpu_has_dc_aliases &&
            page_mapcount(page) && !Page_dcache_dirty(page)) {
                void *vfrom = kmap_coherent(page, vaddr) + (vaddr & ~PAGE_MASK);
                memcpy(dst, vfrom, len);
                kunmap_coherent();
        } else {
                memcpy(dst, src, len);
                if (cpu_has_dc_aliases)
                        SetPageDcacheDirty(page);
        }
}
EXPORT_SYMBOL_GPL(copy_from_user_page);

void __init fixrange_init(unsigned long start, unsigned long end,
        pgd_t *pgd_base)
{
#ifdef CONFIG_HIGHMEM
        pgd_t *pgd;
        pud_t *pud;
        pmd_t *pmd;
        pte_t *pte;
        int i, j, k;
        unsigned long vaddr;

        vaddr = start;
        i = __pgd_offset(vaddr);
        j = __pud_offset(vaddr);
        k = __pmd_offset(vaddr);
        pgd = pgd_base + i;

        for ( ; (i < PTRS_PER_PGD) && (vaddr < end); pgd++, i++) {
                pud = (pud_t *)pgd;
                for ( ; (j < PTRS_PER_PUD) && (vaddr < end); pud++, j++) {
                        pmd = (pmd_t *)pud;
                        for (; (k < PTRS_PER_PMD) && (vaddr < end); pmd++, k++) {
                                if (pmd_none(*pmd)) {
                                        pte = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
                                        set_pmd(pmd, __pmd((unsigned long)pte));
                                        BUG_ON(pte != pte_offset_kernel(pmd, 0));
                                }
                                vaddr += PMD_SIZE;
                        }
                        k = 0;
                }
                j = 0;
        }
#endif
}

unsigned __weak platform_maar_init(unsigned num_pairs)
{
        struct maar_config cfg[BOOT_MEM_MAP_MAX];
        unsigned i, num_configured, num_cfg = 0;
        phys_addr_t skip;

        for (i = 0; i < boot_mem_map.nr_map; i++) {
                switch (boot_mem_map.map[i].type) {
                case BOOT_MEM_RAM:
                case BOOT_MEM_INIT_RAM:
                        break;
                default:
                        continue;
                }

                skip = 0x10000 - (boot_mem_map.map[i].addr & 0xffff);

                cfg[num_cfg].lower = boot_mem_map.map[i].addr;
                cfg[num_cfg].lower += skip;

                cfg[num_cfg].upper = cfg[num_cfg].lower;
                cfg[num_cfg].upper += boot_mem_map.map[i].size - 1;
                cfg[num_cfg].upper -= skip;

                cfg[num_cfg].attrs = MIPS_MAAR_S;
                num_cfg++;
        }

        num_configured = maar_config(cfg, num_cfg, num_pairs);
        if (num_configured < num_cfg)
                pr_warn("Not enough MAAR pairs (%u) for all bootmem regions (%u)\n",
                        num_pairs, num_cfg);

        return num_configured;
}

void maar_init(void)
{
        unsigned num_maars, used, i;
        phys_addr_t lower, upper, attr;
        static struct {
                struct maar_config cfgs[3];
                unsigned used;
        } recorded = { { { 0 } }, 0 };

        if (!cpu_has_maar)
                return;

        /* Detect the number of MAARs */
        write_c0_maari(~0);
        back_to_back_c0_hazard();
        num_maars = read_c0_maari() + 1;

        /* MAARs should be in pairs */
        WARN_ON(num_maars % 2);

        /* Set MAARs using values we recorded already */
        if (recorded.used) {
                used = maar_config(recorded.cfgs, recorded.used, num_maars / 2);
                BUG_ON(used != recorded.used);
        } else {
                /* Configure the required MAARs */
                used = platform_maar_init(num_maars / 2);
        }

        /* Disable any further MAARs */
        for (i = (used * 2); i < num_maars; i++) {
                write_c0_maari(i);
                back_to_back_c0_hazard();
                write_c0_maar(0);
                back_to_back_c0_hazard();
        }

        if (recorded.used)
                return;

        pr_info("MAAR configuration:\n");
        for (i = 0; i < num_maars; i += 2) {
                write_c0_maari(i);
                back_to_back_c0_hazard();
                upper = read_c0_maar();

                write_c0_maari(i + 1);
                back_to_back_c0_hazard();
                lower = read_c0_maar();

                attr = lower & upper;
                lower = (lower & MIPS_MAAR_ADDR) << 4;
                upper = ((upper & MIPS_MAAR_ADDR) << 4) | 0xffff;

                pr_info("  [%d]: ", i / 2);
                if (!(attr & MIPS_MAAR_V)) {
                        pr_cont("disabled\n");
                        continue;
                }

                pr_cont("%pa-%pa", &lower, &upper);

                if (attr & MIPS_MAAR_S)
                        pr_cont(" speculate");

                pr_cont("\n");

                /* Record the setup for use on secondary CPUs */
                if (used <= ARRAY_SIZE(recorded.cfgs)) {
                        recorded.cfgs[recorded.used].lower = lower;
                        recorded.cfgs[recorded.used].upper = upper;
                        recorded.cfgs[recorded.used].attrs = attr;
                        recorded.used++;
                }
        }
}

#ifndef CONFIG_NEED_MULTIPLE_NODES
int page_is_ram(unsigned long pagenr)
{
        int i;

        for (i = 0; i < boot_mem_map.nr_map; i++) {
                unsigned long addr, end;

                switch (boot_mem_map.map[i].type) {
                case BOOT_MEM_RAM:
                case BOOT_MEM_INIT_RAM:
                        break;
                default:
                        /* not usable memory */
                        continue;
                }

                addr = PFN_UP(boot_mem_map.map[i].addr);
                end = PFN_DOWN(boot_mem_map.map[i].addr +
                               boot_mem_map.map[i].size);

                if (pagenr >= addr && pagenr < end)
                        return 1;
        }

        return 0;
}

void __init paging_init(void)
{
        unsigned long max_zone_pfns[MAX_NR_ZONES];
        unsigned long lastpfn __maybe_unused;

        pagetable_init();

#ifdef CONFIG_HIGHMEM
        kmap_init();
#endif
#ifdef CONFIG_ZONE_DMA
        max_zone_pfns[ZONE_DMA] = MAX_DMA_PFN;
#endif
#ifdef CONFIG_ZONE_DMA32
        max_zone_pfns[ZONE_DMA32] = MAX_DMA32_PFN;
#endif
        max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
        lastpfn = max_low_pfn;
#ifdef CONFIG_HIGHMEM
        max_zone_pfns[ZONE_HIGHMEM] = highend_pfn;
        lastpfn = highend_pfn;

        if (cpu_has_dc_aliases && max_low_pfn != highend_pfn) {
                printk(KERN_WARNING "This processor doesn't support highmem."
                       " %ldk highmem ignored\n",
                       (highend_pfn - max_low_pfn) << (PAGE_SHIFT - 10));
                max_zone_pfns[ZONE_HIGHMEM] = max_low_pfn;
                lastpfn = max_low_pfn;
        }
#endif

        free_area_init_nodes(max_zone_pfns);
}

#ifdef CONFIG_64BIT
static struct kcore_list kcore_kseg0;
#endif

static inline void mem_init_free_highmem(void)
{
#ifdef CONFIG_HIGHMEM
        unsigned long tmp;

        for (tmp = highstart_pfn; tmp < highend_pfn; tmp++) {
                struct page *page = pfn_to_page(tmp);

                if (!page_is_ram(tmp))
                        SetPageReserved(page);
                else
                        free_highmem_page(page);
        }
#endif
}

void __init mem_init(void)
{
#ifdef CONFIG_HIGHMEM
#ifdef CONFIG_DISCONTIGMEM
#error "CONFIG_HIGHMEM and CONFIG_DISCONTIGMEM dont work together yet"
#endif
        max_mapnr = highend_pfn ? highend_pfn : max_low_pfn;
#else
        max_mapnr = max_low_pfn;
#endif
        high_memory = (void *) __va(max_low_pfn << PAGE_SHIFT);

        maar_init();
        free_all_bootmem();
        setup_zero_pages();     /* Setup zeroed pages.  */
        mem_init_free_highmem();
        mem_init_print_info(NULL);

#ifdef CONFIG_64BIT
        if ((unsigned long) &_text > (unsigned long) CKSEG0)
                /* The -4 is a hack so that user tools don't have to handle
                   the overflow.  */
                kclist_add(&kcore_kseg0, (void *) CKSEG0,
                                0x80000000 - 4, KCORE_TEXT);
#endif
}
#endif /* !CONFIG_NEED_MULTIPLE_NODES */

void free_init_pages(const char *what, unsigned long begin, unsigned long end)
{
        unsigned long pfn;

        for (pfn = PFN_UP(begin); pfn < PFN_DOWN(end); pfn++) {
                struct page *page = pfn_to_page(pfn);
                void *addr = phys_to_virt(PFN_PHYS(pfn));

                memset(addr, POISON_FREE_INITMEM, PAGE_SIZE);
                free_reserved_page(page);
        }
        printk(KERN_INFO "Freeing %s: %ldk freed\n", what, (end - begin) >> 10);
}

#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

void (*free_init_pages_eva)(void *begin, void *end) = NULL;

void __init_refok free_initmem(void)
{
        prom_free_prom_memory();
        /*
         * Let the platform define a specific function to free the
         * init section since EVA may have used any possible mapping
         * between virtual and physical addresses.
         */
        if (free_init_pages_eva)
                free_init_pages_eva((void *)&__init_begin, (void *)&__init_end);
        else
                free_initmem_default(POISON_FREE_INITMEM);
}

#ifndef CONFIG_MIPS_PGD_C0_CONTEXT
unsigned long pgd_current[NR_CPUS];
#endif

/*
 * gcc 3.3 and older have trouble determining that PTRS_PER_PGD and PGD_ORDER
 * are constants.  So we use the variants from asm-offset.h until that gcc
 * will officially be retired.
 *
 * Align swapper_pg_dir in to 64K, allows its address to be loaded
 * with a single LUI instruction in the TLB handlers.  If we used
 * __aligned(64K), its size would get rounded up to the alignment
 * size, and waste space.  So we place it in its own section and align
 * it in the linker script.
 */
pgd_t swapper_pg_dir[_PTRS_PER_PGD] __section(.bss..swapper_pg_dir);
#ifndef __PAGETABLE_PMD_FOLDED
pmd_t invalid_pmd_table[PTRS_PER_PMD] __page_aligned_bss;
#endif
pte_t invalid_pte_table[PTRS_PER_PTE] __page_aligned_bss;