sun3dvma.c

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/*
 * linux/arch/m68k/sun3/sun3dvma.c
 *
 * Copyright (C) 2000 Sam Creasey
 *
 * Contains common routines for sun3/sun3x DVMA management.
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/gfp.h>
#include <linux/mm.h>
#include <linux/list.h>

#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/dvma.h>

#undef DVMA_DEBUG

#ifdef CONFIG_SUN3X
extern void dvma_unmap_iommu(unsigned long baddr, int len);
#else
static inline void dvma_unmap_iommu(unsigned long a, int b)
{
}
#endif

#ifdef CONFIG_SUN3
extern void sun3_dvma_init(void);
#endif

static unsigned long iommu_use[IOMMU_TOTAL_ENTRIES];

#define dvma_index(baddr) ((baddr - DVMA_START) >> DVMA_PAGE_SHIFT)

#define dvma_entry_use(baddr)       (iommu_use[dvma_index(baddr)])

struct hole {
    unsigned long start;
    unsigned long end;
    unsigned long size;
    struct list_head list;
};

static struct list_head hole_list;
static struct list_head hole_cache;
static struct hole initholes[64];

#ifdef DVMA_DEBUG

static unsigned long dvma_allocs;
static unsigned long dvma_frees;
static unsigned long long dvma_alloc_bytes;
static unsigned long long dvma_free_bytes;

static void print_use(void)
{

    int i;
    int j = 0;

    printk("dvma entry usage:\n");

    for(i = 0; i < IOMMU_TOTAL_ENTRIES; i++) {
        if(!iommu_use[i])
            continue;

        j++;

        printk("dvma entry: %08lx len %08lx\n",
               ( i << DVMA_PAGE_SHIFT) + DVMA_START,
               iommu_use[i]);
    }

    printk("%d entries in use total\n", j);

    printk("allocation/free calls: %lu/%lu\n", dvma_allocs, dvma_frees);
    printk("allocation/free bytes: %Lx/%Lx\n", dvma_alloc_bytes,
           dvma_free_bytes);
}

static void print_holes(struct list_head *holes)
{

    struct list_head *cur;
    struct hole *hole;

    printk("listing dvma holes\n");
    list_for_each(cur, holes) {
        hole = list_entry(cur, struct hole, list);

        if((hole->start == 0) && (hole->end == 0) && (hole->size == 0))
            continue;

        printk("hole: start %08lx end %08lx size %08lx\n", hole->start, hole->end, hole->size);
    }

    printk("end of hole listing...\n");

}
#endif /* DVMA_DEBUG */

static inline int refill(void)
{

    struct hole *hole;
    struct hole *prev = NULL;
    struct list_head *cur;
    int ret = 0;

    list_for_each(cur, &hole_list) {
        hole = list_entry(cur, struct hole, list);

        if(!prev) {
            prev = hole;
            continue;
        }

        if(hole->end == prev->start) {
            hole->size += prev->size;
            hole->end = prev->end;
            list_move(&(prev->list), &hole_cache);
            ret++;
        }

    }

    return ret;
}

static inline struct hole *rmcache(void)
{
    struct hole *ret;

    if(list_empty(&hole_cache)) {
        if(!refill()) {
            printk("out of dvma hole cache!\n");
            BUG();
        }
    }

    ret = list_entry(hole_cache.next, struct hole, list);
    list_del(&(ret->list));

    return ret;

}

static inline unsigned long get_baddr(int len, unsigned long align)
{

    struct list_head *cur;
    struct hole *hole;

    if(list_empty(&hole_list)) {
#ifdef DVMA_DEBUG
        printk("out of dvma holes! (printing hole cache)\n");
        print_holes(&hole_cache);
        print_use();
#endif
        BUG();
    }

    list_for_each(cur, &hole_list) {
        unsigned long newlen;

        hole = list_entry(cur, struct hole, list);

        if(align > DVMA_PAGE_SIZE)
            newlen = len + ((hole->end - len) & (align-1));
        else
            newlen = len;

        if(hole->size > newlen) {
            hole->end -= newlen;
            hole->size -= newlen;
            dvma_entry_use(hole->end) = newlen;
#ifdef DVMA_DEBUG
            dvma_allocs++;
            dvma_alloc_bytes += newlen;
#endif
            return hole->end;
        } else if(hole->size == newlen) {
            list_move(&(hole->list), &hole_cache);
            dvma_entry_use(hole->start) = newlen;
#ifdef DVMA_DEBUG
            dvma_allocs++;
            dvma_alloc_bytes += newlen;
#endif
            return hole->start;
        }

    }

    printk("unable to find dvma hole!\n");
    BUG();
    return 0;
}

static inline int free_baddr(unsigned long baddr)
{

    unsigned long len;
    struct hole *hole;
    struct list_head *cur;
    unsigned long orig_baddr;

    orig_baddr = baddr;
    len = dvma_entry_use(baddr);
    dvma_entry_use(baddr) = 0;
    baddr &= DVMA_PAGE_MASK;
    dvma_unmap_iommu(baddr, len);

#ifdef DVMA_DEBUG
    dvma_frees++;
    dvma_free_bytes += len;
#endif

    list_for_each(cur, &hole_list) {
        hole = list_entry(cur, struct hole, list);

        if(hole->end == baddr) {
            hole->end += len;
            hole->size += len;
            return 0;
        } else if(hole->start == (baddr + len)) {
            hole->start = baddr;
            hole->size += len;
            return 0;
        }

    }

    hole = rmcache();

    hole->start = baddr;
    hole->end = baddr + len;
    hole->size = len;

//  list_add_tail(&(hole->list), cur);
    list_add(&(hole->list), cur);

    return 0;

}

void dvma_init(void)
{

    struct hole *hole;
    int i;

    INIT_LIST_HEAD(&hole_list);
    INIT_LIST_HEAD(&hole_cache);

    /* prepare the hole cache */
    for(i = 0; i < 64; i++)
        list_add(&(initholes[i].list), &hole_cache);

    hole = rmcache();
    hole->start = DVMA_START;
    hole->end = DVMA_END;
    hole->size = DVMA_SIZE;

    list_add(&(hole->list), &hole_list);

    memset(iommu_use, 0, sizeof(iommu_use));

    dvma_unmap_iommu(DVMA_START, DVMA_SIZE);

#ifdef CONFIG_SUN3
    sun3_dvma_init();
#endif

}

inline unsigned long dvma_map_align(unsigned long kaddr, int len, int align)
{

    unsigned long baddr;
    unsigned long off;

    if(!len)
        len = 0x800;

    if(!kaddr || !len) {
//      printk("error: kaddr %lx len %x\n", kaddr, len);
//      *(int *)4 = 0;
        return 0;
    }

#ifdef DEBUG
    printk("dvma_map request %08lx bytes from %08lx\n",
           len, kaddr);
#endif
    off = kaddr & ~DVMA_PAGE_MASK;
    kaddr &= PAGE_MASK;
    len += off;
    len = ((len + (DVMA_PAGE_SIZE-1)) & DVMA_PAGE_MASK);

    if(align == 0)
        align = DVMA_PAGE_SIZE;
    else
        align = ((align + (DVMA_PAGE_SIZE-1)) & DVMA_PAGE_MASK);

    baddr = get_baddr(len, align);
//  printk("using baddr %lx\n", baddr);

    if(!dvma_map_iommu(kaddr, baddr, len))
        return (baddr + off);

    printk("dvma_map failed kaddr %lx baddr %lx len %x\n", kaddr, baddr, len);
    BUG();
    return 0;
}
EXPORT_SYMBOL(dvma_map_align);

void dvma_unmap(void *baddr)
{
    unsigned long addr;

    addr = (unsigned long)baddr;
    /* check if this is a vme mapping */
    if(!(addr & 0x00f00000))
        addr |= 0xf00000;

    free_baddr(addr);

    return;

}
EXPORT_SYMBOL(dvma_unmap);

void *dvma_malloc_align(unsigned long len, unsigned long align)
{
    unsigned long kaddr;
    unsigned long baddr;
    unsigned long vaddr;

    if(!len)
        return NULL;

#ifdef DEBUG
    printk("dvma_malloc request %lx bytes\n", len);
#endif
    len = ((len + (DVMA_PAGE_SIZE-1)) & DVMA_PAGE_MASK);

        if((kaddr = __get_free_pages(GFP_ATOMIC, get_order(len))) == 0)
        return NULL;

    if((baddr = (unsigned long)dvma_map_align(kaddr, len, align)) == 0) {
        free_pages(kaddr, get_order(len));
        return NULL;
    }

    vaddr = dvma_btov(baddr);

    if(dvma_map_cpu(kaddr, vaddr, len) < 0) {
        dvma_unmap((void *)baddr);
        free_pages(kaddr, get_order(len));
        return NULL;
    }

#ifdef DEBUG
    printk("mapped %08lx bytes %08lx kern -> %08lx bus\n",
           len, kaddr, baddr);
#endif

    return (void *)vaddr;

}
EXPORT_SYMBOL(dvma_malloc_align);

void dvma_free(void *vaddr)
{

    return;

}
EXPORT_SYMBOL(dvma_free);