kmap.c

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/*
 *  linux/arch/m68k/mm/kmap.c
 *
 *  Copyright (C) 1997 Roman Hodek
 *
 *  10/01/99 cleaned up the code and changing to the same interface
 *       used by other architectures        /Roman Zippel
 */

#include <linux/module.h>
#include <linux/mm.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>

#include <asm/setup.h>
#include <asm/segment.h>
#include <asm/page.h>
#include <asm/pgalloc.h>
#include <asm/io.h>

#undef DEBUG

#define PTRTREESIZE (256*1024)

/*
 * For 040/060 we can use the virtual memory area like other architectures,
 * but for 020/030 we want to use early termination page descriptor and we
 * can't mix this with normal page descriptors, so we have to copy that code
 * (mm/vmalloc.c) and return appriorate aligned addresses.
 */

#ifdef CPU_M68040_OR_M68060_ONLY

#define IO_SIZE     PAGE_SIZE

static inline struct vm_struct *get_io_area(unsigned long size)
{
    return get_vm_area(size, VM_IOREMAP);
}


static inline void free_io_area(void *addr)
{
    vfree((void *)(PAGE_MASK & (unsigned long)addr));
}

#else

#define IO_SIZE     (256*1024)

static struct vm_struct *iolist;

static struct vm_struct *get_io_area(unsigned long size)
{
    unsigned long addr;
    struct vm_struct **p, *tmp, *area;

    area = kmalloc(sizeof(*area), GFP_KERNEL);
    if (!area)
        return NULL;
    addr = KMAP_START;
    for (p = &iolist; (tmp = *p) ; p = &tmp->next) {
        if (size + addr < (unsigned long)tmp->addr)
            break;
        if (addr > KMAP_END-size) {
            kfree(area);
            return NULL;
        }
        addr = tmp->size + (unsigned long)tmp->addr;
    }
    area->addr = (void *)addr;
    area->size = size + IO_SIZE;
    area->next = *p;
    *p = area;
    return area;
}

static inline void free_io_area(void *addr)
{
    struct vm_struct **p, *tmp;

    if (!addr)
        return;
    addr = (void *)((unsigned long)addr & -IO_SIZE);
    for (p = &iolist ; (tmp = *p) ; p = &tmp->next) {
        if (tmp->addr == addr) {
            *p = tmp->next;
            __iounmap(tmp->addr, tmp->size);
            kfree(tmp);
            return;
        }
    }
}

#endif

/*
 * Map some physical address range into the kernel address space.
 */
/* Rewritten by Andreas Schwab to remove all races. */

void __iomem *__ioremap(unsigned long physaddr, unsigned long size, int cacheflag)
{
    struct vm_struct *area;
    unsigned long virtaddr, retaddr;
    long offset;
    pgd_t *pgd_dir;
    pmd_t *pmd_dir;
    pte_t *pte_dir;

    /*
     * Don't allow mappings that wrap..
     */
    if (!size || physaddr > (unsigned long)(-size))
        return NULL;

#ifdef CONFIG_AMIGA
    if (MACH_IS_AMIGA) {
        if ((physaddr >= 0x40000000) && (physaddr + size < 0x60000000)
            && (cacheflag == IOMAP_NOCACHE_SER))
            return (void __iomem *)physaddr;
    }
#endif

#ifdef DEBUG
    printk("ioremap: 0x%lx,0x%lx(%d) - ", physaddr, size, cacheflag);
#endif
    /*
     * Mappings have to be aligned
     */
    offset = physaddr & (IO_SIZE - 1);
    physaddr &= -IO_SIZE;
    size = (size + offset + IO_SIZE - 1) & -IO_SIZE;

    /*
     * Ok, go for it..
     */
    area = get_io_area(size);
    if (!area)
        return NULL;

    virtaddr = (unsigned long)area->addr;
    retaddr = virtaddr + offset;
#ifdef DEBUG
    printk("0x%lx,0x%lx,0x%lx", physaddr, virtaddr, retaddr);
#endif

    /*
     * add cache and table flags to physical address
     */
    if (CPU_IS_040_OR_060) {
        physaddr |= (_PAGE_PRESENT | _PAGE_GLOBAL040 |
                 _PAGE_ACCESSED | _PAGE_DIRTY);
        switch (cacheflag) {
        case IOMAP_FULL_CACHING:
            physaddr |= _PAGE_CACHE040;
            break;
        case IOMAP_NOCACHE_SER:
        default:
            physaddr |= _PAGE_NOCACHE_S;
            break;
        case IOMAP_NOCACHE_NONSER:
            physaddr |= _PAGE_NOCACHE;
            break;
        case IOMAP_WRITETHROUGH:
            physaddr |= _PAGE_CACHE040W;
            break;
        }
    } else {
        physaddr |= (_PAGE_PRESENT | _PAGE_ACCESSED |
                 _PAGE_DIRTY | _PAGE_READWRITE);
        switch (cacheflag) {
        case IOMAP_NOCACHE_SER:
        case IOMAP_NOCACHE_NONSER:
        default:
            physaddr |= _PAGE_NOCACHE030;
            break;
        case IOMAP_FULL_CACHING:
        case IOMAP_WRITETHROUGH:
            break;
        }
    }

    while ((long)size > 0) {
#ifdef DEBUG
        if (!(virtaddr & (PTRTREESIZE-1)))
            printk ("\npa=%#lx va=%#lx ", physaddr, virtaddr);
#endif
        pgd_dir = pgd_offset_k(virtaddr);
        pmd_dir = pmd_alloc(&init_mm, pgd_dir, virtaddr);
        if (!pmd_dir) {
            printk("ioremap: no mem for pmd_dir\n");
            return NULL;
        }

        if (CPU_IS_020_OR_030) {
            pmd_dir->pmd[(virtaddr/PTRTREESIZE) & 15] = physaddr;
            physaddr += PTRTREESIZE;
            virtaddr += PTRTREESIZE;
            size -= PTRTREESIZE;
        } else {
            pte_dir = pte_alloc_kernel(pmd_dir, virtaddr);
            if (!pte_dir) {
                printk("ioremap: no mem for pte_dir\n");
                return NULL;
            }

            pte_val(*pte_dir) = physaddr;
            virtaddr += PAGE_SIZE;
            physaddr += PAGE_SIZE;
            size -= PAGE_SIZE;
        }
    }
#ifdef DEBUG
    printk("\n");
#endif
    flush_tlb_all();

    return (void __iomem *)retaddr;
}
EXPORT_SYMBOL(__ioremap);

/*
 * Unmap a ioremap()ed region again
 */
void iounmap(void __iomem *addr)
{
#ifdef CONFIG_AMIGA
    if ((!MACH_IS_AMIGA) ||
        (((unsigned long)addr < 0x40000000) ||
         ((unsigned long)addr > 0x60000000)))
            free_io_area((__force void *)addr);
#else
    free_io_area((__force void *)addr);
#endif
}
EXPORT_SYMBOL(iounmap);

/*
 * __iounmap unmaps nearly everything, so be careful
 * it doesn't free currently pointer/page tables anymore but it
 * wans't used anyway and might be added later.
 */
void __iounmap(void *addr, unsigned long size)
{
    unsigned long virtaddr = (unsigned long)addr;
    pgd_t *pgd_dir;
    pmd_t *pmd_dir;
    pte_t *pte_dir;

    while ((long)size > 0) {
        pgd_dir = pgd_offset_k(virtaddr);
        if (pgd_bad(*pgd_dir)) {
            printk("iounmap: bad pgd(%08lx)\n", pgd_val(*pgd_dir));
            pgd_clear(pgd_dir);
            return;
        }
        pmd_dir = pmd_offset(pgd_dir, virtaddr);

        if (CPU_IS_020_OR_030) {
            int pmd_off = (virtaddr/PTRTREESIZE) & 15;
            int pmd_type = pmd_dir->pmd[pmd_off] & _DESCTYPE_MASK;

            if (pmd_type == _PAGE_PRESENT) {
                pmd_dir->pmd[pmd_off] = 0;
                virtaddr += PTRTREESIZE;
                size -= PTRTREESIZE;
                continue;
            } else if (pmd_type == 0)
                continue;
        }

        if (pmd_bad(*pmd_dir)) {
            printk("iounmap: bad pmd (%08lx)\n", pmd_val(*pmd_dir));
            pmd_clear(pmd_dir);
            return;
        }
        pte_dir = pte_offset_kernel(pmd_dir, virtaddr);

        pte_val(*pte_dir) = 0;
        virtaddr += PAGE_SIZE;
        size -= PAGE_SIZE;
    }

    flush_tlb_all();
}

/*
 * Set new cache mode for some kernel address space.
 * The caller must push data for that range itself, if such data may already
 * be in the cache.
 */
void kernel_set_cachemode(void *addr, unsigned long size, int cmode)
{
    unsigned long virtaddr = (unsigned long)addr;
    pgd_t *pgd_dir;
    pmd_t *pmd_dir;
    pte_t *pte_dir;

    if (CPU_IS_040_OR_060) {
        switch (cmode) {
        case IOMAP_FULL_CACHING:
            cmode = _PAGE_CACHE040;
            break;
        case IOMAP_NOCACHE_SER:
        default:
            cmode = _PAGE_NOCACHE_S;
            break;
        case IOMAP_NOCACHE_NONSER:
            cmode = _PAGE_NOCACHE;
            break;
        case IOMAP_WRITETHROUGH:
            cmode = _PAGE_CACHE040W;
            break;
        }
    } else {
        switch (cmode) {
        case IOMAP_NOCACHE_SER:
        case IOMAP_NOCACHE_NONSER:
        default:
            cmode = _PAGE_NOCACHE030;
            break;
        case IOMAP_FULL_CACHING:
        case IOMAP_WRITETHROUGH:
            cmode = 0;
        }
    }

    while ((long)size > 0) {
        pgd_dir = pgd_offset_k(virtaddr);
        if (pgd_bad(*pgd_dir)) {
            printk("iocachemode: bad pgd(%08lx)\n", pgd_val(*pgd_dir));
            pgd_clear(pgd_dir);
            return;
        }
        pmd_dir = pmd_offset(pgd_dir, virtaddr);

        if (CPU_IS_020_OR_030) {
            int pmd_off = (virtaddr/PTRTREESIZE) & 15;

            if ((pmd_dir->pmd[pmd_off] & _DESCTYPE_MASK) == _PAGE_PRESENT) {
                pmd_dir->pmd[pmd_off] = (pmd_dir->pmd[pmd_off] &
                             _CACHEMASK040) | cmode;
                virtaddr += PTRTREESIZE;
                size -= PTRTREESIZE;
                continue;
            }
        }

        if (pmd_bad(*pmd_dir)) {
            printk("iocachemode: bad pmd (%08lx)\n", pmd_val(*pmd_dir));
            pmd_clear(pmd_dir);
            return;
        }
        pte_dir = pte_offset_kernel(pmd_dir, virtaddr);

        pte_val(*pte_dir) = (pte_val(*pte_dir) & _CACHEMASK040) | cmode;
        virtaddr += PAGE_SIZE;
        size -= PAGE_SIZE;
    }

    flush_tlb_all();
}
EXPORT_SYMBOL(kernel_set_cachemode);