/* $Id: init.c,v 1.17 2000-04-08 15:38:54+09 gniibe Exp $
 *
 *  linux/arch/sh/mm/init.c
 *
 *  Copyright (C) 1999  Niibe Yutaka
 *
 *  Based on linux/arch/i386/mm/init.c:
 *   Copyright (C) 1995  Linus Torvalds
 */

#include <linux/config.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/ptrace.h>
#include <linux/mman.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/smp.h>
#include <linux/init.h>
#ifdef CONFIG_BLK_DEV_INITRD
#include <linux/blk.h>
#endif
#include <linux/highmem.h>
#include <linux/bootmem.h>

#include <asm/processor.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/mmu_context.h>
#include <asm/io.h>

/*
 * Cache of MMU context last used.
 */
unsigned long mmu_context_cache;

static unsigned long totalram_pages;
static unsigned long totalhigh_pages;

extern unsigned long init_smp_mappings(unsigned long);

/*
 * BAD_PAGE is the page that is used for page faults when linux
 * is out-of-memory. Older versions of linux just did a
 * do_exit(), but using this instead means there is less risk
 * for a process dying in kernel mode, possibly leaving an inode
 * unused etc..
 *
 * BAD_PAGETABLE is the accompanying page-table: it is initialized
 * to point to BAD_PAGE entries.
 *
 * ZERO_PAGE is a special page that is used for zero-initialized
 * data and COW.
 */

unsigned long empty_bad_page[1024];
pte_t empty_bad_pte_table[PTRS_PER_PTE];
extern unsigned long empty_zero_page[1024];

static pte_t * get_bad_pte_table(void)
{
	pte_t v;
	int i;

	v = pte_mkdirty(mk_pte_phys(__pa(empty_bad_page), PAGE_SHARED));

	for (i = 0; i < PAGE_SIZE/sizeof(pte_t); i++)
		empty_bad_pte_table[i] = v;

	return empty_bad_pte_table;
}

void __handle_bad_pmd(pmd_t *pmd)
{
	pmd_ERROR(*pmd);
	set_pmd(pmd, __pmd(_PAGE_TABLE + __pa(get_bad_pte_table())));
}

void __handle_bad_pmd_kernel(pmd_t *pmd)
{
	pmd_ERROR(*pmd);
	set_pmd(pmd, __pmd(_KERNPG_TABLE + __pa(get_bad_pte_table())));
}

pte_t *get_pte_kernel_slow(pmd_t *pmd, unsigned long offset)
{
	pte_t *pte;

	pte = (pte_t *) __get_free_page(GFP_KERNEL);
	if (pmd_none(*pmd)) {
		if (pte) {
			clear_page(pte);
			set_pmd(pmd, __pmd(_KERNPG_TABLE + __pa(pte)));
			return pte + offset;
		}
		set_pmd(pmd, __pmd(_KERNPG_TABLE + __pa(get_bad_pte_table())));
		return NULL;
	}
	free_page((unsigned long)pte);
	if (pmd_bad(*pmd)) {
		__handle_bad_pmd_kernel(pmd);
		return NULL;
	}
	return (pte_t *) pmd_page(*pmd) + offset;
}

pte_t *get_pte_slow(pmd_t *pmd, unsigned long offset)
{
	unsigned long pte;

	pte = (unsigned long) __get_free_page(GFP_KERNEL);
	if (pmd_none(*pmd)) {
		if (pte) {
			clear_page((void *)pte);
			set_pmd(pmd, __pmd(_PAGE_TABLE + __pa(pte)));
			return (pte_t *)pte + offset;
		}
		set_pmd(pmd, __pmd(_PAGE_TABLE + __pa(get_bad_pte_table())));
		return NULL;
	}
	free_page(pte);
	if (pmd_bad(*pmd)) {
		__handle_bad_pmd(pmd);
		return NULL;
	}
	return (pte_t *) pmd_page(*pmd) + offset;
}

int do_check_pgt_cache(int low, int high)
{
	int freed = 0;
	if (pgtable_cache_size > high) {
		do {
			if (pgd_quicklist)
				free_pgd_slow(get_pgd_fast()), freed++;
			if (pmd_quicklist)
				free_pmd_slow(get_pmd_fast()), freed++;
			if (pte_quicklist)
				free_pte_slow(get_pte_fast()), freed++;
		} while (pgtable_cache_size > low);
	}
	return freed;
}

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

	printk("Mem-info:\n");
	show_free_areas();
	printk("Free swap:       %6dkB\n",nr_swap_pages<<(PAGE_SHIFT-10));
	i = max_mapnr;
	while (i-- > 0) {
		total++;
		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 reserved pages\n",reserved);
	printk("%d pages shared\n",shared);
	printk("%d pages swap cached\n",cached);
	printk("%ld pages in page table cache\n",pgtable_cache_size);
	show_buffers();
}

/* References to section boundaries */

extern char _text, _etext, _edata, __bss_start, _end;
extern char __init_begin, __init_end;

pgd_t swapper_pg_dir[1024];

/* It'd be good if these lines were in the standard header file. */
#define START_PFN	(NODE_DATA(0)->bdata->node_boot_start >> PAGE_SHIFT)
#define MAX_LOW_PFN	(NODE_DATA(0)->bdata->node_low_pfn)

/*
 * paging_init() sets up the page tables
 *
 * This routines also unmaps the page at virtual kernel address 0, so
 * that we can trap those pesky NULL-reference errors in the kernel.
 */
void __init paging_init(void)
{
	int i;
	pgd_t * pg_dir;

	/* We don't need kernel mapping as hardware support that. */
	pg_dir = swapper_pg_dir;

	for (i=0; i < USER_PTRS_PER_PGD*2; i++)
		pgd_val(pg_dir[i]) = 0;

	/* Enable MMU */
	ctrl_outl(MMU_CONTROL_INIT, MMUCR);

	/* The manual suggests doing some nops after turning on the MMU */
	asm volatile("nop;nop;nop;nop;nop;nop;");

	mmu_context_cache = MMU_CONTEXT_FIRST_VERSION;
	set_asid(mmu_context_cache & MMU_CONTEXT_ASID_MASK);

 	{
		unsigned long zones_size[MAX_NR_ZONES] = {0, 0, 0};
		unsigned long max_dma, low, start_pfn;

		start_pfn = START_PFN;
		max_dma = virt_to_phys((char *)MAX_DMA_ADDRESS) >> PAGE_SHIFT;
		low = MAX_LOW_PFN;

		if (low < max_dma)
			zones_size[ZONE_DMA] = low - start_pfn;
		else {
			zones_size[ZONE_DMA] = max_dma - start_pfn;
			zones_size[ZONE_NORMAL] = low - max_dma;
		}
		free_area_init_node(0, 0, 0, zones_size, __MEMORY_START, 0);
 	}
}

void __init mem_init(void)
{
	int codesize, reservedpages, datasize, initsize;
	int tmp;

	max_mapnr = num_physpages = MAX_LOW_PFN - START_PFN;
	high_memory = (void *)__va(MAX_LOW_PFN * PAGE_SIZE);

	/* clear the zero-page */
	memset(empty_zero_page, 0, PAGE_SIZE);
	flush_page_to_ram(virt_to_page(empty_zero_page));

	/* this will put all low memory onto the freelists */
	totalram_pages += free_all_bootmem();
	reservedpages = 0;
	for (tmp = 0; tmp < num_physpages; tmp++)
		/*
		 * Only count reserved RAM pages
		 */
		if (PageReserved(mem_map+tmp))
			reservedpages++;
	codesize =  (unsigned long) &_etext - (unsigned long) &_text;
	datasize =  (unsigned long) &_edata - (unsigned long) &_etext;
	initsize =  (unsigned long) &__init_end - (unsigned long) &__init_begin;

	printk("Memory: %luk/%luk available (%dk kernel code, %dk reserved, %dk data, %dk init)\n",
		(unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
		max_mapnr << (PAGE_SHIFT-10),
		codesize >> 10,
		reservedpages << (PAGE_SHIFT-10),
		datasize >> 10,
		initsize >> 10);
}

void free_initmem(void)
{
	unsigned long addr;
	
	addr = (unsigned long)(&__init_begin);
	for (; addr < (unsigned long)(&__init_end); addr += PAGE_SIZE) {
		ClearPageReserved(virt_to_page(addr));
		set_page_count(virt_to_page(addr), 1);
		free_page(addr);
		totalram_pages++;
	}
	printk ("Freeing unused kernel memory: %dk freed\n", (&__init_end - &__init_begin) >> 10);
}

#ifdef CONFIG_BLK_DEV_INITRD
void free_initrd_mem(unsigned long start, unsigned long end)
{
	unsigned long p;
	for (p = start; p < end; p += PAGE_SIZE) {
		ClearPageReserved(virt_to_page(p));
		set_page_count(virt_to_page(p), 1);
		free_page(p);
		totalram_pages++;
	}
	printk ("Freeing initrd memory: %ldk freed\n", (end - start) >> 10);
}
#endif

void si_meminfo(struct sysinfo *val)
{
	val->totalram = totalram_pages;
	val->sharedram = 0;
	val->freeram = nr_free_pages();
	val->bufferram = atomic_read(&buffermem_pages);
	val->totalhigh = totalhigh_pages;
	val->freehigh = nr_free_highpages();
	val->mem_unit = PAGE_SIZE;
	return;
}