source: rtems/cpukit/libdrvmgr/drvmgr_for_each_dev.c @ 7075fb11

/* Iterate over device tree topology, breadth or depth-first
 *
 * COPYRIGHT (c) 2009 Cobham Gaisler AB.
 *
 * The license and distribution terms for this file may be
 * found in the file LICENSE in this distribution or at
 * http://www.rtems.org/license/LICENSE.
 */

#include <string.h>
#include <drvmgr/drvmgr.h>
#include <drvmgr/drvmgr_list.h>
#include "drvmgr_internal.h"

/* Traverse device tree breadth-first. Supports up to 31 buses */
static int drvmgr_for_each_dev_breadth(
        int (*func)(struct drvmgr_dev *dev, void *arg),
        void *arg
        )
{
        int ret = 0, i, pos;
        struct drvmgr_bus *bus, *buses[32];
        struct drvmgr_dev *dev;

        pos = 0;
        memset(&buses[0], 0, sizeof(buses));
        buses[pos++] = drvmgr.root_dev.bus;     /* Get root bus */

        for (i = 0, bus = buses[0]; buses[i]; i++, bus = buses[i]) {
                dev = bus->children;
                while (dev) {
                        ret = func(dev, arg);
                        if (ret != 0)
                                break;
                        if (dev->bus && pos < 31)
                                buses[pos++] = dev->bus;

                        dev = dev->next_in_bus;
                }
        }

        return ret;
}

/* Traverse device tree depth-first. */
static int drvmgr_for_each_dev_depth(
        int (*func)(struct drvmgr_dev *dev, void *arg),
        void *arg
        )
{
        int ret = 0;
        struct drvmgr_dev *dev;

        /* Get first device */
        dev = drvmgr.root_dev.bus->children;

        while (dev) {
                ret = func(dev, arg);
                if (ret != 0)
                        break;
                if (dev->bus && dev->bus->children) {
                        dev = dev->bus->children;
                } else {
next_dev:
                        if (dev->next_in_bus == NULL) {
                                /* Step up one level... back to parent bus */
                                dev = dev->parent->dev;
                                if (dev == &drvmgr.root_dev)
                                        break;
                                goto next_dev;
                        } else {
                                dev = dev->next_in_bus;
                        }
                }
        }

        return ret;
}

/* Traverse device tree depth-first or breadth-first */
int drvmgr_for_each_dev(
        int (*func)(struct drvmgr_dev *dev, void *arg),
        void *arg,
        int options
        )
{
        int ret;

        DRVMGR_LOCK_READ();

        /* Get Root Device */
        if (drvmgr.root_dev.bus->children != NULL) {
                if (options & DRVMGR_FED_BF)
                        ret = drvmgr_for_each_dev_breadth(func, arg);
                else
                        ret = drvmgr_for_each_dev_depth(func, arg);
        } else
                ret = 0;

        DRVMGR_UNLOCK();

        return ret;
}