/*
   * 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/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 <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/mmu_context.h>
  #include <asm/sections.h>
  #include <asm/pgtable.h>
  #include <asm/pgalloc.h>
  #include <asm/tlb.h>

  #include <asm/fixmap.h>
  
  /* Atomicity and interruptability */
  #ifdef CONFIG_MIPS_MT_SMTC
  
  #include <asm/mipsmtregs.h>
  
  #define ENTER_CRITICAL(flags) \
  	{ \
  	unsigned int mvpflags; \
  	local_irq_save(flags);\
  	mvpflags = dvpe()
  #define EXIT_CRITICAL(flags) \
  	evpe(mvpflags); \
  	local_irq_restore(flags); \
  	}
  #else
  
  #define ENTER_CRITICAL(flags) local_irq_save(flags)
  #define EXIT_CRITICAL(flags) local_irq_restore(flags)
  
  #endif /* CONFIG_MIPS_MT_SMTC */

  
  DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);

  /*
   * 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;
  
  /*
   * Not static inline because used by IP27 special magic initialization code
   */
  unsigned long setup_zero_pages(void)
  {

  	unsigned int order;
  	unsigned long size;

  	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);

  	while (page < virt_to_page((void *)(empty_zero_page + (PAGE_SIZE << order)))) {

  		SetPageReserved(page);

  		page++;
  	}
  
  	size = PAGE_SIZE << order;
  	zero_page_mask = (size - 1) & PAGE_MASK;
  
  	return 1UL << order;
  }

  /*
   * These are almost like kmap_atomic / kunmap_atmic except they take an
   * additional address argument as the hint.
   */

  
  #define kmap_get_fixmap_pte(vaddr)					\

  	pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), (vaddr)), (vaddr)), (vaddr))

  #ifdef CONFIG_MIPS_MT_SMTC
  static pte_t *kmap_coherent_pte;
  static void __init kmap_coherent_init(void)
  {
  	unsigned long vaddr;
  
  	/* cache the first coherent kmap pte */
  	vaddr = __fix_to_virt(FIX_CMAP_BEGIN);
  	kmap_coherent_pte = kmap_get_fixmap_pte(vaddr);
  }
  #else
  static inline void kmap_coherent_init(void) {}
  #endif

  void *kmap_coherent(struct page *page, unsigned long addr)

  {
  	enum fixed_addresses idx;
  	unsigned long vaddr, flags, entrylo;
  	unsigned long old_ctx;
  	pte_t pte;
  	int tlbidx;

  	BUG_ON(Page_dcache_dirty(page));

  	inc_preempt_count();
  	idx = (addr >> PAGE_SHIFT) & (FIX_N_COLOURS - 1);
  #ifdef CONFIG_MIPS_MT_SMTC
  	idx += FIX_N_COLOURS * smp_processor_id();
  #endif
  	vaddr = __fix_to_virt(FIX_CMAP_END - idx);
  	pte = mk_pte(page, PAGE_KERNEL);
  #if defined(CONFIG_64BIT_PHYS_ADDR) && defined(CONFIG_CPU_MIPS32_R1)
  	entrylo = pte.pte_high;
  #else
  	entrylo = pte_val(pte) >> 6;
  #endif
  
  	ENTER_CRITICAL(flags);
  	old_ctx = read_c0_entryhi();
  	write_c0_entryhi(vaddr & (PAGE_MASK << 1));
  	write_c0_entrylo0(entrylo);
  	write_c0_entrylo1(entrylo);
  #ifdef CONFIG_MIPS_MT_SMTC
  	set_pte(kmap_coherent_pte - (FIX_CMAP_END - idx), pte);
  	/* preload TLB instead of local_flush_tlb_one() */
  	mtc0_tlbw_hazard();
  	tlb_probe();
  	tlb_probe_hazard();
  	tlbidx = read_c0_index();
  	mtc0_tlbw_hazard();
  	if (tlbidx < 0)
  		tlb_write_random();
  	else
  		tlb_write_indexed();
  #else
  	tlbidx = read_c0_wired();
  	write_c0_wired(tlbidx + 1);
  	write_c0_index(tlbidx);
  	mtc0_tlbw_hazard();
  	tlb_write_indexed();
  #endif
  	tlbw_use_hazard();
  	write_c0_entryhi(old_ctx);
  	EXIT_CRITICAL(flags);
  
  	return (void*) vaddr;
  }
  
  #define UNIQUE_ENTRYHI(idx) (CKSEG0 + ((idx) << (PAGE_SHIFT + 1)))

  void kunmap_coherent(void)

  {
  #ifndef CONFIG_MIPS_MT_SMTC
  	unsigned int wired;
  	unsigned long flags, old_ctx;
  
  	ENTER_CRITICAL(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);
  	EXIT_CRITICAL(flags);
  #endif
  	dec_preempt_count();
  	preempt_check_resched();
  }

  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, KM_USER1);

  	if (cpu_has_dc_aliases && page_mapped(from)) {

  		vfrom = kmap_coherent(from, vaddr);
  		copy_page(vto, vfrom);

  		kunmap_coherent();

  	} else {
  		vfrom = kmap_atomic(from, KM_USER0);
  		copy_page(vto, vfrom);
  		kunmap_atomic(vfrom, KM_USER0);
  	}
  	if (((vma->vm_flags & VM_EXEC) && !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, KM_USER1);
  	/* Make sure this page is cleared on other CPU's too before using it */
  	smp_wmb();
  }
  
  EXPORT_SYMBOL(copy_user_highpage);

  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_mapped(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));
  }
  
  EXPORT_SYMBOL(copy_to_user_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_mapped(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(copy_from_user_page);
  
  
  #ifdef CONFIG_HIGHMEM

  unsigned long highstart_pfn, highend_pfn;

  pte_t *kmap_pte;
  pgprot_t kmap_prot;

  static void __init kmap_init(void)
  {
  	unsigned long kmap_vstart;
  
  	/* cache the first kmap pte */
  	kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
  	kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
  
  	kmap_prot = PAGE_KERNEL;
  }

  #endif /* CONFIG_HIGHMEM */

  void __init fixrange_init(unsigned long start, unsigned long end,

  	pgd_t *pgd_base)
  {

  #if defined(CONFIG_HIGHMEM) || defined(CONFIG_MIPS_MT_SMTC)

  	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));

  					if (pte != pte_offset_kernel(pmd, 0))
  						BUG();
  				}
  				vaddr += PMD_SIZE;

  			}

  			k = 0;

  		}
  		j = 0;
  	}

  #endif

  }

  #ifndef CONFIG_NEED_MULTIPLE_NODES

  static int __init page_is_ram(unsigned long pagenr)
  {
  	int i;
  
  	for (i = 0; i < boot_mem_map.nr_map; i++) {
  		unsigned long addr, end;
  
  		if (boot_mem_map.map[i].type != BOOT_MEM_RAM)
  			/* 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;

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

  	kmap_coherent_init();

  #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
  ",
  		       (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);

  }

  static struct kcore_list kcore_mem, kcore_vmalloc;
  #ifdef CONFIG_64BIT
  static struct kcore_list kcore_kseg0;
  #endif

  void __init mem_init(void)
  {
  	unsigned long codesize, reservedpages, datasize, initsize;
  	unsigned long tmp, ram;
  
  #ifdef CONFIG_HIGHMEM
  #ifdef CONFIG_DISCONTIGMEM
  #error "CONFIG_HIGHMEM and CONFIG_DISCONTIGMEM dont work together yet"
  #endif

  	max_mapnr = highend_pfn;

  #else

  	max_mapnr = max_low_pfn;

  #endif
  	high_memory = (void *) __va(max_low_pfn << PAGE_SHIFT);
  
  	totalram_pages += free_all_bootmem();
  	totalram_pages -= setup_zero_pages();	/* Setup zeroed pages.  */
  
  	reservedpages = ram = 0;
  	for (tmp = 0; tmp < max_low_pfn; tmp++)
  		if (page_is_ram(tmp)) {
  			ram++;

  			if (PageReserved(pfn_to_page(tmp)))

  				reservedpages++;
  		}

  	num_physpages = ram;

  
  #ifdef CONFIG_HIGHMEM
  	for (tmp = highstart_pfn; tmp < highend_pfn; tmp++) {

  		struct page *page = pfn_to_page(tmp);

  
  		if (!page_is_ram(tmp)) {
  			SetPageReserved(page);
  			continue;
  		}
  		ClearPageReserved(page);

  		init_page_count(page);

  		__free_page(page);
  		totalhigh_pages++;
  	}
  	totalram_pages += totalhigh_pages;

  	num_physpages += totalhigh_pages;

  #endif
  
  	codesize =  (unsigned long) &_etext - (unsigned long) &_text;
  	datasize =  (unsigned long) &_edata - (unsigned long) &_etext;
  	initsize =  (unsigned long) &__init_end - (unsigned long) &__init_begin;

  #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);
  #endif
  	kclist_add(&kcore_mem, __va(0), max_low_pfn << PAGE_SHIFT);
  	kclist_add(&kcore_vmalloc, (void *)VMALLOC_START,
  		   VMALLOC_END-VMALLOC_START);

  	printk(KERN_INFO "Memory: %luk/%luk available (%ldk kernel code, "
  	       "%ldk reserved, %ldk data, %ldk init, %ldk highmem)
  ",
  	       (unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
  	       ram << (PAGE_SHIFT-10),
  	       codesize >> 10,
  	       reservedpages << (PAGE_SHIFT-10),
  	       datasize >> 10,
  	       initsize >> 10,
  	       (unsigned long) (totalhigh_pages << (PAGE_SHIFT-10)));
  }

  #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));
  
  		ClearPageReserved(page);
  		init_page_count(page);
  		memset(addr, POISON_FREE_INITMEM, PAGE_SIZE);
  		__free_page(page);

  		totalram_pages++;
  	}
  	printk(KERN_INFO "Freeing %s: %ldk freed
  ", what, (end - begin) >> 10);
  }

  #ifdef CONFIG_BLK_DEV_INITRD
  void free_initrd_mem(unsigned long start, unsigned long end)
  {

  	free_init_pages("initrd memory",
  			virt_to_phys((void *)start),
  			virt_to_phys((void *)end));

  }
  #endif

  void __init_refok free_initmem(void)

  {

  	prom_free_prom_memory();

  	free_init_pages("unused kernel memory",
  			__pa_symbol(&__init_begin),
  			__pa_symbol(&__init_end));

  }

  
  unsigned long pgd_current[NR_CPUS];
  /*
   * On 64-bit we've got three-level pagetables with a slightly
   * different layout ...
   */
  #define __page_aligned(order) __attribute__((__aligned__(PAGE_SIZE<<order)))

  
  /*
   * 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.
   */
  pgd_t swapper_pg_dir[_PTRS_PER_PGD] __page_aligned(_PGD_ORDER);

  #ifdef CONFIG_64BIT
  #ifdef MODULE_START
  pgd_t module_pg_dir[PTRS_PER_PGD] __page_aligned(PGD_ORDER);
  #endif
  pmd_t invalid_pmd_table[PTRS_PER_PMD] __page_aligned(PMD_ORDER);
  #endif
  pte_t invalid_pte_table[PTRS_PER_PTE] __page_aligned(PTE_ORDER);