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/*

 * linux/arch/m68k/motorola.c

 *

 * Routines specific to the Motorola MMU, originally from:

 * linux/arch/m68k/init.c

 * which are Copyright (C) 1995 Hamish Macdonald

 *

 * Moved 8/20/1999 Sam Creasey

 */

#include <linux/config.h>

#include <linux/signal.h>

#include <linux/sched.h>

#include <linux/mm.h>

#include <linux/swap.h>

#include <linux/kernel.h>

#include <linux/string.h>

#include <linux/types.h>

#include <linux/init.h>

#include <linux/bootmem.h>

#ifdef CONFIG_BLK_DEV_RAM

#include <linux/blk.h>

#endif

#include <asm/setup.h>

#include <asm/uaccess.h>

#include <asm/page.h>

#include <asm/pgalloc.h>

#include <asm/system.h>

#include <asm/machdep.h>

#include <asm/io.h>

#include <asm/dma.h>

#ifdef CONFIG_ATARI

#include <asm/atari_stram.h>

#endif

#undef DEBUG

#ifndef mm_cachebits

/*

 * Bits to add to page descriptors for "normal" caching mode.

 * For 68020/030 this is 0.

 * For 68040, this is _PAGE_CACHE040 (cachable, copyback)

 */

unsigned long mm_cachebits = 0;

#endif

static pte_t * __init kernel_page_table(void)

{

        pte_t *ptablep;

        ptablep = (pte_t *)alloc_bootmem_low_pages(PAGE_SIZE);

        clear_page(ptablep);

        __flush_page_to_ram((unsigned long) ptablep);

        flush_tlb_kernel_page((unsigned long) ptablep);

        nocache_page ((unsigned long)ptablep);

        return ptablep;

}

static pmd_t *last_pgtable __initdata = NULL;

pmd_t *zero_pgtable __initdata = NULL;

static pmd_t * __init kernel_ptr_table(void)

{

        if (!last_pgtable) {

                unsigned long pmd, last;

                int i;

                /* Find the last ptr table that was used in head.S and

                 * reuse the remaining space in that page for further

                 * ptr tables.

                 */

                last = (unsigned long)kernel_pg_dir;

                for (i = 0; i < PTRS_PER_PGD; i++) {

                        if (!pgd_present(kernel_pg_dir[i]))

                                continue;

                        pmd = __pgd_page(kernel_pg_dir[i]);

                        if (pmd > last)

                                last = pmd;

                }

                last_pgtable = (pmd_t *)last;

#ifdef DEBUG

                printk("kernel_ptr_init: %p\n", last_pgtable);

#endif

        }

        if (((unsigned long)(last_pgtable + PTRS_PER_PMD) & ~PAGE_MASK) == 0) {

                last_pgtable = (pmd_t *)alloc_bootmem_low_pages(PAGE_SIZE);

                clear_page(last_pgtable);

                __flush_page_to_ram((unsigned long)last_pgtable);

                flush_tlb_kernel_page((unsigned long)last_pgtable);

                nocache_page((unsigned long)last_pgtable);

        } else

                last_pgtable += PTRS_PER_PMD;

        return last_pgtable;

}

static unsigned long __init

map_chunk (unsigned long addr, long size)

{

#define PTRTREESIZE (256*1024)

#define ROOTTREESIZE (32*1024*1024)

        static unsigned long virtaddr = PAGE_OFFSET;

        unsigned long physaddr;

        pgd_t *pgd_dir;

        pmd_t *pmd_dir;

        pte_t *pte_dir;

        physaddr = (addr | m68k_supervisor_cachemode |

                    _PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_DIRTY);

        if (CPU_IS_040_OR_060)

                physaddr |= _PAGE_GLOBAL040;

        while (size > 0) {

#ifdef DEBUG

                if (!(virtaddr & (PTRTREESIZE-1)))

                        printk ("\npa=%#lx va=%#lx ", physaddr & PAGE_MASK,

                                virtaddr);

#endif

                pgd_dir = pgd_offset_k(virtaddr);

                if (virtaddr && CPU_IS_020_OR_030) {

                        if (!(virtaddr & (ROOTTREESIZE-1)) &&

                            size >= ROOTTREESIZE) {

#ifdef DEBUG

                                printk ("[very early term]");

#endif

                                pgd_val(*pgd_dir) = physaddr;

                                size -= ROOTTREESIZE;

                                virtaddr += ROOTTREESIZE;

                                physaddr += ROOTTREESIZE;

                                continue;

                        }

                }

                if (!pgd_present(*pgd_dir)) {

                        pmd_dir = kernel_ptr_table();

#ifdef DEBUG

                        printk ("[new pointer %p]", pmd_dir);

#endif

                        pgd_set(pgd_dir, pmd_dir);

                } else

                        pmd_dir = pmd_offset(pgd_dir, virtaddr);

                if (CPU_IS_020_OR_030) {

                        if (virtaddr) {

#ifdef DEBUG

                                printk ("[early term]");

#endif

                                pmd_dir->pmd[(virtaddr/PTRTREESIZE) & 15] = physaddr;

                                physaddr += PTRTREESIZE;

                        } else {

                                int i;

#ifdef DEBUG

                                printk ("[zero map]");

#endif

                                zero_pgtable = kernel_ptr_table();

                                pte_dir = (pte_t *)zero_pgtable;

                                pmd_dir->pmd[0] = virt_to_phys(pte_dir) |

                                        _PAGE_TABLE | _PAGE_ACCESSED;

                                pte_val(*pte_dir++) = 0;

                                physaddr += PAGE_SIZE;

                                for (i = 1; i < 64; physaddr += PAGE_SIZE, i++)

                                        pte_val(*pte_dir++) = physaddr;

                        }

                        size -= PTRTREESIZE;

                        virtaddr += PTRTREESIZE;

                } else {

                        if (!pmd_present(*pmd_dir)) {

#ifdef DEBUG

                                printk ("[new table]");

#endif

                                pte_dir = kernel_page_table();

                                pmd_set(pmd_dir, pte_dir);

                        }

                        pte_dir = pte_offset(pmd_dir, virtaddr);

                        if (virtaddr) {

                                if (!pte_present(*pte_dir))

                                        pte_val(*pte_dir) = physaddr;

                        } else

                                pte_val(*pte_dir) = 0;

                        size -= PAGE_SIZE;

                        virtaddr += PAGE_SIZE;

                        physaddr += PAGE_SIZE;

                }

        }

#ifdef DEBUG

        printk("\n");

#endif

        return virtaddr;

}

extern unsigned long empty_bad_page_table;

extern unsigned long empty_bad_page;

/*

 * paging_init() continues the virtual memory environment setup which

 * was begun by the code in arch/head.S.

 */

void __init paging_init(void)

{

        int chunk;

        unsigned long mem_avail = 0;

        unsigned long zones_size[3] = { 0, };

#ifdef DEBUG

        {

                extern unsigned long availmem;

                printk ("start of paging_init (%p, %lx, %lx, %lx)\n",

                        kernel_pg_dir, availmem, start_mem, end_mem);

        }

#endif

        /* Fix the cache mode in the page descriptors for the 680[46]0.  */

        if (CPU_IS_040_OR_060) {

                int i;

#ifndef mm_cachebits

                mm_cachebits = _PAGE_CACHE040;

#endif

                for (i = 0; i < 16; i++)

                        pgprot_val(protection_map[i]) |= _PAGE_CACHE040;

        }

        /*

         * Map the physical memory available into the kernel virtual

         * address space.  It may allocate some memory for page

         * tables and thus modify availmem.

         */

        for (chunk = 0; chunk < m68k_num_memory; chunk++) {

                mem_avail = map_chunk (m68k_memory[chunk].addr,

                                       m68k_memory[chunk].size);

        }

        flush_tlb_all();

#ifdef DEBUG

        printk ("memory available is %ldKB\n", mem_avail >> 10);

        printk ("start_mem is %#lx\nvirtual_end is %#lx\n",

                start_mem, end_mem);

#endif

        /*

         * initialize the bad page table and bad page to point

         * to a couple of allocated pages

         */

        empty_bad_page_table = (unsigned long)alloc_bootmem_pages(PAGE_SIZE);

        empty_bad_page = (unsigned long)alloc_bootmem_pages(PAGE_SIZE);

        empty_zero_page = (unsigned long)alloc_bootmem_pages(PAGE_SIZE);

        memset((void *)empty_zero_page, 0, PAGE_SIZE);

        /*

         * Set up SFC/DFC registers (user data space)

         */

        set_fs (USER_DS);

#ifdef DEBUG

        printk ("before free_area_init\n");

#endif

        zones_size[0] = (mach_max_dma_address < (unsigned long)high_memory ?

                         mach_max_dma_address : (unsigned long)high_memory);

        zones_size[1] = (unsigned long)high_memory - zones_size[0];

        zones_size[0] = (zones_size[0] - PAGE_OFFSET) >> PAGE_SHIFT;

        zones_size[1] >>= PAGE_SHIFT;

        free_area_init(zones_size);

}

extern char __init_begin, __init_end;

extern unsigned long totalram_pages;

void free_initmem(void)

{

        unsigned long addr;

        addr = (unsigned long)&__init_begin;

        for (; addr < (unsigned long)&__init_end; addr += PAGE_SIZE) {

                virt_to_page(addr)->flags &= ~(1 << PG_reserved);

                set_page_count(virt_to_page(addr), 1);

                free_page(addr);

                totalram_pages++;

        }

}