Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

/*

 * 2002-10-18  written by Jim Houston jim.houston@ccur.com

 *      Copyright (C) 2002 by Concurrent Computer Corporation

 *      Distributed under the GNU GPL license version 2.

 *

 * Modified by George Anzinger to reuse immediately and to use

 * find bit instructions.  Also removed _irq on spinlocks.

 *

 * Small id to pointer translation service.

 *

 * It uses a radix tree like structure as a sparse array indexed

 * by the id to obtain the pointer.  The bitmap makes allocating

 * a new id quick.

 *

 * You call it to allocate an id (an int) an associate with that id a

 * pointer or what ever, we treat it as a (void *).  You can pass this

 * id to a user for him to pass back at a later time.  You then pass

 * that id to this code and it returns your pointer.

 * You can release ids at any time. When all ids are released, most of

 * the memory is returned (we keep IDR_FREE_MAX) in a local pool so we

 * don't need to go to the memory "store" during an id allocate, just

 * so you don't need to be too concerned about locking and conflicts

 * with the slab allocator.

 */

#ifndef TEST                        // to test in user space...

#include <linux/slab.h>

#include <linux/init.h>

#include <linux/module.h>

#endif

#include <linux/err.h>

#include <linux/string.h>

#include <linux/idr.h>

static struct kmem_cache *idr_layer_cache;

static struct idr_layer *alloc_layer(struct idr *idp)

{

        struct idr_layer *p;

        unsigned long flags;

        spin_lock_irqsave(&idp->lock, flags);

        if ((p = idp->id_free)) {

                idp->id_free = p->ary[0];

                idp->id_free_cnt--;

                p->ary[0] = NULL;

        }

        spin_unlock_irqrestore(&idp->lock, flags);

        return(p);

}

/* only called when idp->lock is held */

static void __free_layer(struct idr *idp, struct idr_layer *p)

{

        p->ary[0] = idp->id_free;

        idp->id_free = p;

        idp->id_free_cnt++;

}

static void free_layer(struct idr *idp, struct idr_layer *p)

{

        unsigned long flags;

        /*

         * Depends on the return element being zeroed.

         */

        spin_lock_irqsave(&idp->lock, flags);

        __free_layer(idp, p);

        spin_unlock_irqrestore(&idp->lock, flags);

}

static void idr_mark_full(struct idr_layer **pa, int id)

{

        struct idr_layer *p = pa[0];

        int l = 0;

        __set_bit(id & IDR_MASK, &p->bitmap);

        /*

         * If this layer is full mark the bit in the layer above to

         * show that this part of the radix tree is full.  This may

         * complete the layer above and require walking up the radix

         * tree.

         */

        while (p->bitmap == IDR_FULL) {

                if (!(p = pa[++l]))

                        break;

                id = id >> IDR_BITS;

                __set_bit((id & IDR_MASK), &p->bitmap);

        }

}

/**

 * idr_pre_get - reserver resources for idr allocation

 * @idp:        idr handle

 * @gfp_mask:   memory allocation flags

 *

 * This function should be called prior to locking and calling the

 * following function.  It preallocates enough memory to satisfy

 * the worst possible allocation.

 *

 * If the system is REALLY out of memory this function returns 0,

 * otherwise 1.

 */

int idr_pre_get(struct idr *idp, gfp_t gfp_mask)

{

        while (idp->id_free_cnt < IDR_FREE_MAX) {

                struct idr_layer *new;

                new = kmem_cache_alloc(idr_layer_cache, gfp_mask);

                if (new == NULL)

                        return (0);

                free_layer(idp, new);

        }

        return 1;

}

EXPORT_SYMBOL(idr_pre_get);

static int sub_alloc(struct idr *idp, int *starting_id, struct idr_layer **pa)

{

        int n, m, sh;

        struct idr_layer *p, *new;

        int l, id, oid;

        unsigned long bm;

        id = *starting_id;

 restart:

        p = idp->top;

        l = idp->layers;

        pa[l--] = NULL;

        while (1) {

                /*

                 * We run around this while until we reach the leaf node...

                 */

                n = (id >> (IDR_BITS*l)) & IDR_MASK;

                bm = ~p->bitmap;

                m = find_next_bit(&bm, IDR_SIZE, n);

                if (m == IDR_SIZE) {

                        /* no space available go back to previous layer. */

                        l++;

                        oid = id;

                        id = (id | ((1 << (IDR_BITS * l)) - 1)) + 1;

                        /* if already at the top layer, we need to grow */

                        if (!(p = pa[l])) {

                                *starting_id = id;

                                return -2;

                        }

                        /* If we need to go up one layer, continue the

                         * loop; otherwise, restart from the top.

                         */

                        sh = IDR_BITS * (l + 1);

                        if (oid >> sh == id >> sh)

                                continue;

                        else

                                goto restart;

                }

                if (m != n) {

                        sh = IDR_BITS*l;

                        id = ((id >> sh) ^ n ^ m) << sh;

                }

                if ((id >= MAX_ID_BIT) || (id < 0))

                        return -3;

                if (l == 0)

                        break;

                /*

                 * Create the layer below if it is missing.

                 */

                if (!p->ary[m]) {

                        if (!(new = alloc_layer(idp)))

                                return -1;

                        p->ary[m] = new;

                        p->count++;

                }

                pa[l--] = p;

                p = p->ary[m];

        }

        pa[l] = p;

        return id;

}

static int idr_get_empty_slot(struct idr *idp, int starting_id,

                              struct idr_layer **pa)

{

        struct idr_layer *p, *new;

        int layers, v, id;

        unsigned long flags;

        id = starting_id;

build_up:

        p = idp->top;

        layers = idp->layers;

        if (unlikely(!p)) {

                if (!(p = alloc_layer(idp)))

                        return -1;

                layers = 1;

        }

        /*

         * Add a new layer to the top of the tree if the requested

         * id is larger than the currently allocated space.

         */

        while ((layers < (MAX_LEVEL - 1)) && (id >= (1 << (layers*IDR_BITS)))) {

                layers++;

                if (!p->count)

                        continue;

                if (!(new = alloc_layer(idp))) {

                        /*

                         * The allocation failed.  If we built part of

                         * the structure tear it down.

                         */

                        spin_lock_irqsave(&idp->lock, flags);

                        for (new = p; p && p != idp->top; new = p) {

                                p = p->ary[0];

                                new->ary[0] = NULL;

                                new->bitmap = new->count = 0;

                                __free_layer(idp, new);

                        }

                        spin_unlock_irqrestore(&idp->lock, flags);

                        return -1;

                }

                new->ary[0] = p;

                new->count = 1;

                if (p->bitmap == IDR_FULL)

                        __set_bit(0, &new->bitmap);

                p = new;

        }

        idp->top = p;

        idp->layers = layers;

        v = sub_alloc(idp, &id, pa);

        if (v == -2)

                goto build_up;

        return(v);

}

static int idr_get_new_above_int(struct idr *idp, void *ptr, int starting_id)

{

        struct idr_layer *pa[MAX_LEVEL];

        int id;

        id = idr_get_empty_slot(idp, starting_id, pa);

        if (id >= 0) {

                /*

                 * Successfully found an empty slot.  Install the user

                 * pointer and mark the slot full.

                 */

                pa[0]->ary[id & IDR_MASK] = (struct idr_layer *)ptr;

                pa[0]->count++;

                idr_mark_full(pa, id);

        }

        return id;

}

/**

 * idr_get_new_above - allocate new idr entry above or equal to a start id

 * @idp: idr handle

 * @ptr: pointer you want associated with the ide

 * @start_id: id to start search at

 * @id: pointer to the allocated handle

 *

 * This is the allocate id function.  It should be called with any

 * required locks.

 *

 * If memory is required, it will return -EAGAIN, you should unlock

 * and go back to the idr_pre_get() call.  If the idr is full, it will

 * return -ENOSPC.

 *

 * @id returns a value in the range 0 ... 0x7fffffff

 */

int idr_get_new_above(struct idr *idp, void *ptr, int starting_id, int *id)

{

        int rv;

        rv = idr_get_new_above_int(idp, ptr, starting_id);

        /*

         * This is a cheap hack until the IDR code can be fixed to

         * return proper error values.

         */

        if (rv < 0) {

                if (rv == -1)

                        return -EAGAIN;

                else /* Will be -3 */

                        return -ENOSPC;

        }

        *id = rv;

        return 0;

}

EXPORT_SYMBOL(idr_get_new_above);

/**

 * idr_get_new - allocate new idr entry

 * @idp: idr handle

 * @ptr: pointer you want associated with the ide

 * @id: pointer to the allocated handle

 *

 * This is the allocate id function.  It should be called with any

 * required locks.

 *

 * If memory is required, it will return -EAGAIN, you should unlock

 * and go back to the idr_pre_get() call.  If the idr is full, it will

 * return -ENOSPC.

 *

 * @id returns a value in the range 0 ... 0x7fffffff

 */

int idr_get_new(struct idr *idp, void *ptr, int *id)

{

        int rv;

        rv = idr_get_new_above_int(idp, ptr, 0);

        /*

         * This is a cheap hack until the IDR code can be fixed to

         * return proper error values.

         */

        if (rv < 0) {

                if (rv == -1)

                        return -EAGAIN;

                else /* Will be -3 */

                        return -ENOSPC;

        }

        *id = rv;

        return 0;

}

EXPORT_SYMBOL(idr_get_new);

static void idr_remove_warning(int id)

{

        printk("idr_remove called for id=%d which is not allocated.\n", id);

        dump_stack();

}

static void sub_remove(struct idr *idp, int shift, int id)

{

        struct idr_layer *p = idp->top;

        struct idr_layer **pa[MAX_LEVEL];

        struct idr_layer ***paa = &pa[0];

        int n;

        *paa = NULL;

        *++paa = &idp->top;

        while ((shift > 0) && p) {

                n = (id >> shift) & IDR_MASK;

                __clear_bit(n, &p->bitmap);

                *++paa = &p->ary[n];

                p = p->ary[n];

                shift -= IDR_BITS;

        }

        n = id & IDR_MASK;

        if (likely(p != NULL && test_bit(n, &p->bitmap))){

                __clear_bit(n, &p->bitmap);

                p->ary[n] = NULL;

                while(*paa && ! --((**paa)->count)){

                        free_layer(idp, **paa);

                        **paa-- = NULL;

                }

                if (!*paa)

                        idp->layers = 0;

        } else

                idr_remove_warning(id);

}

/**

 * idr_remove - remove the given id and free it's slot

 * @idp: idr handle

 * @id: unique key

 */

void idr_remove(struct idr *idp, int id)

{

        struct idr_layer *p;

        /* Mask off upper bits we don't use for the search. */

        id &= MAX_ID_MASK;

        sub_remove(idp, (idp->layers - 1) * IDR_BITS, id);

        if (idp->top && idp->top->count == 1 && (idp->layers > 1) &&

            idp->top->ary[0]) {  // We can drop a layer

                p = idp->top->ary[0];

                idp->top->bitmap = idp->top->count = 0;

                free_layer(idp, idp->top);

                idp->top = p;

                --idp->layers;

        }

        while (idp->id_free_cnt >= IDR_FREE_MAX) {

                p = alloc_layer(idp);

                kmem_cache_free(idr_layer_cache, p);

                return;

        }

}

EXPORT_SYMBOL(idr_remove);

/**

 * idr_remove_all - remove all ids from the given idr tree

 * @idp: idr handle

 *

 * idr_destroy() only frees up unused, cached idp_layers, but this

 * function will remove all id mappings and leave all idp_layers

 * unused.

 *

 * A typical clean-up sequence for objects stored in an idr tree, will

 * use idr_for_each() to free all objects, if necessay, then

 * idr_remove_all() to remove all ids, and idr_destroy() to free

 * up the cached idr_layers.

 */

void idr_remove_all(struct idr *idp)

{

        int n, id, max;

        struct idr_layer *p;

        struct idr_layer *pa[MAX_LEVEL];

        struct idr_layer **paa = &pa[0];

        n = idp->layers * IDR_BITS;

        p = idp->top;

        max = 1 << n;

        id = 0;

        while (id < max) {

                while (n > IDR_BITS && p) {

                        n -= IDR_BITS;

                        *paa++ = p;

                        p = p->ary[(id >> n) & IDR_MASK];

                }

                id += 1 << n;

                while (n < fls(id)) {

                        if (p) {

                                memset(p, 0, sizeof *p);

                                free_layer(idp, p);

                        }

                        n += IDR_BITS;

                        p = *--paa;

                }

        }

        idp->top = NULL;

        idp->layers = 0;

}

EXPORT_SYMBOL(idr_remove_all);

/**

 * idr_destroy - release all cached layers within an idr tree

 * idp: idr handle

 */

void idr_destroy(struct idr *idp)

{

        while (idp->id_free_cnt) {

                struct idr_layer *p = alloc_layer(idp);

                kmem_cache_free(idr_layer_cache, p);

        }

}

EXPORT_SYMBOL(idr_destroy);

/**

 * idr_find - return pointer for given id

 * @idp: idr handle

 * @id: lookup key

 *

 * Return the pointer given the id it has been registered with.  A %NULL

 * return indicates that @id is not valid or you passed %NULL in

 * idr_get_new().

 *

 * The caller must serialize idr_find() vs idr_get_new() and idr_remove().

 */

void *idr_find(struct idr *idp, int id)

{

        int n;

        struct idr_layer *p;

        n = idp->layers * IDR_BITS;

        p = idp->top;

        /* Mask off upper bits we don't use for the search. */

        id &= MAX_ID_MASK;

        if (id >= (1 << n))

                return NULL;

        while (n > 0 && p) {

                n -= IDR_BITS;

                p = p->ary[(id >> n) & IDR_MASK];

        }

        return((void *)p);

}

EXPORT_SYMBOL(idr_find);

/**

 * idr_for_each - iterate through all stored pointers

 * @idp: idr handle

 * @fn: function to be called for each pointer

 * @data: data passed back to callback function

 *

 * Iterate over the pointers registered with the given idr.  The

 * callback function will be called for each pointer currently

 * registered, passing the id, the pointer and the data pointer passed

 * to this function.  It is not safe to modify the idr tree while in

 * the callback, so functions such as idr_get_new and idr_remove are

 * not allowed.

 *

 * We check the return of @fn each time. If it returns anything other

 * than 0, we break out and return that value.

 *

 * The caller must serialize idr_for_each() vs idr_get_new() and idr_remove().

 */

int idr_for_each(struct idr *idp,

                 int (*fn)(int id, void *p, void *data), void *data)

{

        int n, id, max, error = 0;

        struct idr_layer *p;

        struct idr_layer *pa[MAX_LEVEL];

        struct idr_layer **paa = &pa[0];

        n = idp->layers * IDR_BITS;

        p = idp->top;

        max = 1 << n;

        id = 0;

        while (id < max) {

                while (n > 0 && p) {

                        n -= IDR_BITS;

                        *paa++ = p;

                        p = p->ary[(id >> n) & IDR_MASK];

                }

                if (p) {

                        error = fn(id, (void *)p, data);

                        if (error)

                                break;

                }

                id += 1 << n;

                while (n < fls(id)) {

                        n += IDR_BITS;

                        p = *--paa;

                }

        }

        return error;

}

EXPORT_SYMBOL(idr_for_each);

/**

 * idr_replace - replace pointer for given id

 * @idp: idr handle

 * @ptr: pointer you want associated with the id

 * @id: lookup key

 *

 * Replace the pointer registered with an id and return the old value.

 * A -ENOENT return indicates that @id was not found.

 * A -EINVAL return indicates that @id was not within valid constraints.

 *

 * The caller must serialize vs idr_find(), idr_get_new(), and idr_remove().

 */

void *idr_replace(struct idr *idp, void *ptr, int id)

{

        int n;

        struct idr_layer *p, *old_p;

        n = idp->layers * IDR_BITS;

        p = idp->top;

        id &= MAX_ID_MASK;

        if (id >= (1 << n))

                return ERR_PTR(-EINVAL);

        n -= IDR_BITS;

        while ((n > 0) && p) {

                p = p->ary[(id >> n) & IDR_MASK];

                n -= IDR_BITS;

        }

        n = id & IDR_MASK;

        if (unlikely(p == NULL || !test_bit(n, &p->bitmap)))

                return ERR_PTR(-ENOENT);

        old_p = p->ary[n];

        p->ary[n] = ptr;

        return old_p;

}

EXPORT_SYMBOL(idr_replace);

static void idr_cache_ctor(struct kmem_cache *idr_layer_cache, void *idr_layer)

{

        memset(idr_layer, 0, sizeof(struct idr_layer));

}

static  int init_id_cache(void)

{

        if (!idr_layer_cache)

                idr_layer_cache = kmem_cache_create("idr_layer_cache",

                        sizeof(struct idr_layer), 0, 0, idr_cache_ctor);

        return 0;

}

/**

 * idr_init - initialize idr handle

 * @idp:        idr handle

 *

 * This function is use to set up the handle (@idp) that you will pass

 * to the rest of the functions.

 */

void idr_init(struct idr *idp)

{

        init_id_cache();

        memset(idp, 0, sizeof(struct idr));

        spin_lock_init(&idp->lock);

}

EXPORT_SYMBOL(idr_init);

/*

 * IDA - IDR based ID allocator

 *

 * this is id allocator without id -> pointer translation.  Memory

 * usage is much lower than full blown idr because each id only

 * occupies a bit.  ida uses a custom leaf node which contains

 * IDA_BITMAP_BITS slots.

 *

 * 2007-04-25  written by Tejun Heo <htejun@gmail.com>

 */

static void free_bitmap(struct ida *ida, struct ida_bitmap *bitmap)

{

        unsigned long flags;

        if (!ida->free_bitmap) {

                spin_lock_irqsave(&ida->idr.lock, flags);

                if (!ida->free_bitmap) {

                        ida->free_bitmap = bitmap;

                        bitmap = NULL;

                }

                spin_unlock_irqrestore(&ida->idr.lock, flags);

        }

        kfree(bitmap);

}

/**

 * ida_pre_get - reserve resources for ida allocation

 * @ida:        ida handle

 * @gfp_mask:   memory allocation flag

 *

 * This function should be called prior to locking and calling the

 * following function.  It preallocates enough memory to satisfy the

 * worst possible allocation.

 *

 * If the system is REALLY out of memory this function returns 0,

 * otherwise 1.

 */

int ida_pre_get(struct ida *ida, gfp_t gfp_mask)

{

        /* allocate idr_layers */

        if (!idr_pre_get(&ida->idr, gfp_mask))

                return 0;

        /* allocate free_bitmap */

        if (!ida->free_bitmap) {

                struct ida_bitmap *bitmap;

                bitmap = kmalloc(sizeof(struct ida_bitmap), gfp_mask);

                if (!bitmap)

                        return 0;

                free_bitmap(ida, bitmap);

        }

        return 1;

}

EXPORT_SYMBOL(ida_pre_get);

/**

 * ida_get_new_above - allocate new ID above or equal to a start id

 * @ida:        ida handle

 * @staring_id: id to start search at

 * @p_id:       pointer to the allocated handle

 *

 * Allocate new ID above or equal to @ida.  It should be called with

 * any required locks.

 *

 * If memory is required, it will return -EAGAIN, you should unlock

 * and go back to the ida_pre_get() call.  If the ida is full, it will

 * return -ENOSPC.

 *

 * @p_id returns a value in the range 0 ... 0x7fffffff.

 */

int ida_get_new_above(struct ida *ida, int starting_id, int *p_id)

{

        struct idr_layer *pa[MAX_LEVEL];

        struct ida_bitmap *bitmap;

        unsigned long flags;