root/arch/m68k/sun3/sun3dvma.c
// SPDX-License-Identifier: GPL-2.0
/*
 * linux/arch/m68k/sun3/sun3dvma.c
 *
 * Copyright (C) 2000 Sam Creasey
 *
 * Contains common routines for sun3/sun3x DVMA management.
 */

#include <linux/memblock.h>
#include <linux/init.h>
#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/dvma.h>

#undef DVMA_DEBUG

static unsigned long *iommu_use;

#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;

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

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

                j++;

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

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

        pr_info("allocation/free calls: %lu/%lu\n", dvma_allocs, dvma_frees);
        pr_info("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;

        pr_info("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;

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

        pr_info("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()) {
                        pr_crit("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
                pr_crit("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;
                }

        }

        pr_crit("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;

        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 __init 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);

        iommu_use = memblock_alloc_or_panic(IOMMU_TOTAL_ENTRIES * sizeof(unsigned long),
                                   SMP_CACHE_BYTES);
        dvma_unmap_iommu(DVMA_START, DVMA_SIZE);

        sun3_dvma_init();
}

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

        pr_debug("dvma_map request %08x bytes from %08lx\n", len, kaddr);
        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);
//      pr_info("using baddr %lx\n", baddr);

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

        pr_crit("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;

        pr_debug("dvma_malloc request %lx bytes\n", len);
        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;
        }

        pr_debug("mapped %08lx bytes %08lx kern -> %08lx bus\n", len, kaddr,
                 baddr);

        return (void *)vaddr;

}
EXPORT_SYMBOL(dvma_malloc_align);

void dvma_free(void *vaddr)
{

        return;

}
EXPORT_SYMBOL(dvma_free);