source: rtems/cpukit/libdrvmgr/drvmgr.c @ 6d21a3f2

/* Driver Manager Interface Implementation.
 *
 * 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 <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <drvmgr/drvmgr.h>
#include <drvmgr/drvmgr_confdefs.h>

#include <rtems/sysinit.h>

#include "drvmgr_internal.h"

/* Enable debugging */
/*#define DEBUG 1*/

#ifdef DEBUG
#define DBG(x...) printk(x)
#else
#define DBG(x...)
#endif

struct drvmgr drvmgr = {
        .level =                0,
        .initializing_objs =    0,
        .lock =                 API_MUTEX_INITIALIZER("_Drvmgr"),
        .root_dev =             {0},
        .root_drv =             NULL,

        .drivers =      LIST_INITIALIZER(struct drvmgr_drv, next),

        .buses = {
                LIST_INITIALIZER(struct drvmgr_bus, next),
                LIST_INITIALIZER(struct drvmgr_bus, next),
                LIST_INITIALIZER(struct drvmgr_bus, next),
                LIST_INITIALIZER(struct drvmgr_bus, next),
                LIST_INITIALIZER(struct drvmgr_bus, next),
        },
        .buses_inactive =       LIST_INITIALIZER(struct drvmgr_bus, next),

        .devices = {
                LIST_INITIALIZER(struct drvmgr_dev, next),
                LIST_INITIALIZER(struct drvmgr_dev, next),
                LIST_INITIALIZER(struct drvmgr_dev, next),
                LIST_INITIALIZER(struct drvmgr_dev, next),
                LIST_INITIALIZER(struct drvmgr_dev, next),
        },
        .devices_inactive =     LIST_INITIALIZER(struct drvmgr_dev, next),
};

static int do_bus_init(
        struct drvmgr *mgr,
        struct drvmgr_bus *bus,
        int level);
static int do_dev_init(
        struct drvmgr *mgr,
        struct drvmgr_dev *dev,
        int level);

/* DRIVER MANAGER */

void _DRV_Manager_init_level(int level)
{
        struct drvmgr *mgr = &drvmgr;

        if (mgr->level >= level)
                return;

        /* Set new Level */
        mgr->level = level;

        /* Initialize buses and devices into this new level */
        drvmgr_init_update();
}

/* Initialize Data structures of the driver manager and call driver
 * register functions configured by the user.
 */
void _DRV_Manager_initialization(void)
{
        drvmgr_drv_reg_func *drvreg;

        /* Call driver register functions. */
        drvreg = &drvmgr_drivers[0];
        while (*drvreg) {
                /* Make driver register */
                (*drvreg)();
                drvreg++;
        }
}

/* Take ready devices and buses into the correct init level step by step.
 * Once a bus or a device has been registered there is no turning
 * back - they are taken to the level of the driver manager.
 */
void drvmgr_init_update(void)
{
        struct drvmgr *mgr = &drvmgr;
        struct drvmgr_bus *bus;
        struct drvmgr_dev *dev;
        int bus_might_been_registered;
        int level;

        /* "Lock" to make sure we don't use up the stack and that the lists
         * remain consistent.
         */
        DRVMGR_LOCK_WRITE();
        if (mgr->initializing_objs || (mgr->level == 0))
                goto out;
        mgr->initializing_objs = 1;

        /* Take all buses and devices ready into the same stage
         * as the driver manager global level.
         */
        for (level = 0; level < mgr->level; level++) {

                bus_might_been_registered = 0;

                /* Take buses into next level */

                while ((bus = BUS_LIST_HEAD(&mgr->buses[level])) != NULL) {

                        /* Remove first in the list (will be inserted in
                         * appropriate list by do_bus_init())
                         */
                        drvmgr_list_remove_head(&mgr->buses[level]);

                        DRVMGR_UNLOCK();

                        /* Initialize Bus, this will register devices on
                         * the bus. Take bus into next level.
                         */
                        do_bus_init(mgr, bus, level+1);

                        DRVMGR_LOCK_WRITE();
                }

                /* Take devices into next level */
                while ((dev = DEV_LIST_HEAD(&mgr->devices[level])) != NULL) {

                        /* Always process first in list */
                        dev = DEV_LIST_HEAD(&mgr->devices[level]);

                        /* Remove first in the list (will be inserted in
                         * appropriate list by do_dev_init())
                         */
                        drvmgr_list_remove_head(&mgr->devices[level]);

                        DRVMGR_UNLOCK();

                        /* Initialize Device, this may register a new bus */
                        do_dev_init(mgr, dev, level+1);

                        DRVMGR_LOCK_WRITE();

                        bus_might_been_registered = 1;
                }

                /* Make sure all buses registered and ready are taken at
                 * the same time into init level N.
                 */
                if (bus_might_been_registered) {
                        level = -1; /* restart loop */
                }
        }

        /* Release bus/device initialization "Lock" */
        mgr->initializing_objs = 0;

out:
        DRVMGR_UNLOCK();
}

/* Take bus into next level */
static int do_bus_init(
        struct drvmgr *mgr,
        struct drvmgr_bus *bus,
        int level)
{
        int (*init)(struct drvmgr_bus *);

        /* If bridge device has failed during initialization, the bus is not
         * initialized further.
         */
        if (bus->dev->state & DEV_STATE_INIT_FAILED) {
                bus->state |= BUS_STATE_DEPEND_FAILED;
                goto inactivate_out;
        }

        if (bus->ops && (init = bus->ops->init[level-1])) {
                /* Note: This init1 function may register new devices */
                bus->error = init(bus);
                if (bus->error != DRVMGR_OK) {
                        /* An error of some kind during bus initialization.
                         *
                         * Child devices and their buses are not inactived
                         * directly here, instead they will all be catched by
                         * do_dev_init() and do_bus_init() by checking if
                         * parent or bridge-device failed. We know that
                         * initialization will happen later for those devices.
                         */
                        goto inactivate_out;
                }
        }

        DRVMGR_LOCK_WRITE();

        /* Bus taken into the new level */
        bus->level = level;

        /* Put bus into list of buses reached level 'level'.
         * Put at end of bus list so that init[N+1]() calls comes
         * in the same order as init[N]()
         */
        drvmgr_list_add_tail(&mgr->buses[level], bus);

        DRVMGR_UNLOCK();

        return 0;

inactivate_out:
        DRVMGR_LOCK_WRITE();
        bus->state |= BUS_STATE_INIT_FAILED;
        bus->state |= BUS_STATE_LIST_INACTIVE;
        drvmgr_list_add_head(&mgr->buses_inactive, bus);
        DRVMGR_UNLOCK();

        DBG("do_bus_init(%d): (DEV: %s) failed\n", level, bus->dev->name);

        return 1;
}

/* Take device to initialization level 1 */
static int do_dev_init(
        struct drvmgr *mgr,
        struct drvmgr_dev *dev,
        int level)
{
        int (*init)(struct drvmgr_dev *);

        /* Try to allocate Private Device Structure for driver if driver
         * requests for this feature.
         */
        if (dev->drv && dev->drv->dev_priv_size && !dev->priv) {
                dev->priv = malloc(dev->drv->dev_priv_size);
                memset(dev->priv, 0, dev->drv->dev_priv_size);
        }

        /* If parent bus has failed during initialization,
         * the device is not initialized further.
         */
        if (dev->parent && (dev->parent->state & BUS_STATE_INIT_FAILED)) {
                dev->state |= DEV_STATE_DEPEND_FAILED;
                goto inactivate_out;
        }

        /* Call Driver's Init Routine */
        if (dev->drv && (init = dev->drv->ops->init[level-1])) {
                /* Note: This init function may register new devices */
                dev->error = init(dev);
                if (dev->error != DRVMGR_OK) {
                        /* An error of some kind has occured in the
                         * driver/device, the failed device is put into the
                         * inactive list, this way Init2,3 and/or 4 will not
                         * be called for this device.
                         *
                         * The device is not removed from the bus (not
                         * unregistered). The driver can be used to find
                         * device information and debugging for example even
                         * if device initialization failed.
                         *
                         * Child buses and their devices are not inactived
                         * directly here, instead they will all be catched by
                         * do_dev_init() and do_bus_init() by checking if
                         * parent or bridge-device failed. We know that
                         * initialization will happen later for those devices.
                         */
                        goto inactivate_out;
                }
        }

        DRVMGR_LOCK_WRITE();
        /* Dev taken into new level */
        dev->level = level;

        /* Put at end of device list so that init[N+1]() calls comes
         * in the same order as init[N]()
         */
        drvmgr_list_add_tail(&mgr->devices[level], dev);
        DRVMGR_UNLOCK();

        return 0;

inactivate_out:
        DRVMGR_LOCK_WRITE();
        dev->state |= DEV_STATE_INIT_FAILED;
        dev->state |= DEV_STATE_LIST_INACTIVE;
        drvmgr_list_add_head(&mgr->devices_inactive, dev);
        DRVMGR_UNLOCK();

        DBG("do_dev_init(%d): DRV: %s (DEV: %s) failed\n",
                level, dev->drv->name, dev->name);

        return 1; /* Failed to take device into requested level */
}

/* Register Root device driver */
int drvmgr_root_drv_register(struct drvmgr_drv *drv)
{
        struct drvmgr *mgr = &drvmgr;
        struct drvmgr_dev *root = &mgr->root_dev;

        if (mgr->root_drv) {
                /* Only possible to register root device once */
                return DRVMGR_FAIL;
        }

        /* Set root device driver */
        drv->next = NULL;
        mgr->root_drv = drv;

        /* Init root device non-NULL fields */
        root->minor_drv = -1;
        root->minor_bus = 0;
        root->businfo = mgr;
        root->name = "root bus";
        /* Custom Driver association */
        root->drv = mgr->root_drv;

        /* This registers the root device and a bus */
        drvmgr_dev_register(root);

        return DRVMGR_OK;
}

/* Register a driver */
int drvmgr_drv_register(struct drvmgr_drv *drv)
{
        struct drvmgr *mgr = &drvmgr;

        /* All drivers must have been registered before start of init, 
         * because the manager does not scan all existing devices to find
         * suitable hardware for this driver, and it is not protected with
         * a lock therefore.
         */
        if (mgr->level > 0)
                return -1;

        drv->obj_type = DRVMGR_OBJ_DRV;

        /* Put driver into list of registered drivers */
        drvmgr_list_add_head(&mgr->drivers, drv);

        /* TODO: we could scan for devices that this new driver has support
         *       for. However, at this stage we assume that all drivers are
         *       registered before devices are registered.
         *
         * LOCK: From the same assumsion locking the driver list is not needed
         *       either.
         */

        return 0;
}

/* Insert a device into a driver's device list and assign a driver minor number
 * to the device.
 *
 * The devices are ordered by their minor number (sorted linked list of devices)
 * the minor number is found by looking for a gap or at the end.
 */
static void drvmgr_insert_dev_into_drv(
        struct drvmgr_drv *drv,
        struct drvmgr_dev *dev)
{
        struct drvmgr_dev *curr, **pprevnext;
        int minor;

        minor = 0;
        pprevnext = &drv->dev;
        curr = drv->dev;

        while (curr) {
                if (minor < curr->minor_drv) {
                        /* Found a gap. Insert new device between prev
                         * and curr. */
                        break;
                }
                minor++;
                pprevnext = &curr->next_in_drv;
                curr = curr->next_in_drv;
        }
        dev->next_in_drv = curr;
        *pprevnext = dev;

        /* Set minor */
        dev->minor_drv = minor;
        drv->dev_cnt++;
}

/* Insert a device into a bus device list and assign a bus minor number to the
 * device.
 *
 * The devices are ordered by their minor number (sorted linked list of devices)
 * and by their registeration order if not using the same driver.
 *
 * The minor number is found by looking for a gap or at the end.
 */
static void drvmgr_insert_dev_into_bus(
        struct drvmgr_bus *bus,
        struct drvmgr_dev *dev)
{
        struct drvmgr_dev *curr, **pprevnext;
        int minor;

        minor = 0;
        pprevnext = &bus->children;
        curr = bus->children;

        while (curr) {
                if (dev->drv && (dev->drv == curr->drv)) {
                        if (minor < curr->minor_bus) {
                                /* Found a gap. Insert new device between prev
                                 * and curr. */
                                break;
                        }
                        minor++;
                }
                pprevnext = &curr->next_in_bus;
                curr = curr->next_in_bus;
        }
        dev->next_in_bus = curr;
        *pprevnext = dev;

        /* Set minor. Devices without driver are given -1 */
        if (dev->drv == NULL)
                minor = -1;
        dev->minor_bus = minor;
        bus->dev_cnt++;
}

/* Try to find a driver for a device (unite a device with driver).
 * a device with a driver
 */
static struct drvmgr_drv *drvmgr_dev_find_drv(
                struct drvmgr_dev *dev)
{
        struct drvmgr *mgr = &drvmgr;
        struct drvmgr_drv *drv;

        /* NOTE: No locking is needed here since Driver list is supposed to be
         *       initialized once during startup, we treat it as a static
         *       read-only list
         */

        /* Try to find a driver that can handle this device */
        for (drv = DRV_LIST_HEAD(&mgr->drivers); drv; drv = drv->next)
                if (dev->parent->ops->unite(drv, dev) == 1)
                        break;

        return drv;
}

/* Register a device */
int drvmgr_dev_register(struct drvmgr_dev *dev)
{
        struct drvmgr *mgr = &drvmgr;
        struct drvmgr_drv *drv;
        struct drvmgr_bus *bus = dev->parent;
        struct drvmgr_key *keys;
        struct drvmgr_list *init_list = &mgr->devices_inactive;

        DBG("DEV_REG: %s at bus \"%s\"\n", dev->name,
                bus && bus->dev && bus->dev->name ? bus->dev->name : "UNKNOWN");

        /* Custom driver assocation? */
        if (dev->drv) {
                drv = dev->drv;
                DBG("CUSTOM ASSOCIATION (%s to %s)\n", dev->name, drv->name);
        } else {
                /* Try to find a driver that can handle this device */
                dev->drv = drv = drvmgr_dev_find_drv(dev);
        }

        DRVMGR_LOCK_WRITE();

        /* Assign Bus Minor number and put into bus device list
         * unless root device.
         */
        if (bus)
                drvmgr_insert_dev_into_bus(bus, dev);

        if (!drv) {
                /* No driver found that can handle this device, put into
                 * inactive list
                 */
                dev->minor_drv = -1;
                dev->state |= DEV_STATE_LIST_INACTIVE;
        } else {
                /* United device with driver.
                 * Put the device on the registered device list
                 */
                dev->state |= DEV_STATE_UNITED;

                /* Check if user want to skip this core. This is not a
                 * normal request, however in a multi-processor system
                 * the two(or more) RTEMS instances must not use the same
                 * devices in a system, not reporting a device to
                 * it's driver will effectively accomplish this. In a
                 * non Plug & Play system one can easily avoid this
                 * problem by not report the core, but in a Plug & Play
                 * system the bus driver will report all found cores.
                 *
                 * To stop the two RTEMS instances from using the same
                 * device the user can simply define a resource entry
                 * for a certain device but set the keys field to NULL.
                 */
                if (drvmgr_keys_get(dev, &keys) == 0 && keys == NULL) {
                        /* Found Driver resource entry point
                         * for this device, it was NULL, this
                         * indicates to skip the core.
                         *
                         * We put it into the inactive list
                         * marking it as ignored.
                         */
                        dev->state |= DEV_STATE_IGNORED;
                } else {
                        /* Assign Driver Minor number and put into driver's
                         * device list
                         */
                        drvmgr_insert_dev_into_drv(drv, dev);

                        /* Just register device, it will be initialized
                         * later together with bus.
                         *
                         * At the end of the list (breadth first search)
                         */
                        init_list = &mgr->devices[0];

                        DBG("Registered %s (DRV: %s) on %s\n",
                                dev->name, drv->name,
                                bus ? bus->dev->name : "NO PARENT");
                }
        }

        drvmgr_list_add_tail(init_list, dev);

        DRVMGR_UNLOCK();

        /* Trigger Device initialization if not root device and
         * has a driver
         */
        if (bus && dev->drv)
                drvmgr_init_update();

        return 0;
}

/* Register a bus */
int drvmgr_bus_register(struct drvmgr_bus *bus)
{
        struct drvmgr *mgr = &drvmgr;
        struct drvmgr_bus *bus_up;

        /* Get bus architecture depth - the distance from root bus */
        bus->depth = 0;
        bus_up = bus->dev->parent;
        while (bus_up) {
                bus->depth++;
                bus_up = bus_up->dev->parent;
        }

        DRVMGR_LOCK_WRITE();

        /* Put driver into list of found buses */
        drvmgr_list_add_tail(&mgr->buses[0], bus);

        DRVMGR_UNLOCK();

        /* Take bus into level1 and so on */
        drvmgr_init_update();

        return 0;
}

/* Allocate memory for a Device structure */
int drvmgr_alloc_dev(struct drvmgr_dev **pdev, int extra)
{
        struct drvmgr_dev *dev;
        int size;

        /* The extra memory "service" is aligned to 4 bytes boundary. */
        size = ((sizeof(struct drvmgr_dev) + 3) & ~0x3) + extra;
        dev = (struct drvmgr_dev *)calloc(size, 1);
        if (!dev) {
                /* Failed to allocate device structure - critical error */
                rtems_fatal_error_occurred(RTEMS_NO_MEMORY);
        }
        *pdev = dev;
        dev->obj_type = DRVMGR_OBJ_DEV;

        return 0;
}

/* Allocate memory for a Bus structure */
int drvmgr_alloc_bus(struct drvmgr_bus **pbus, int extra)
{
        struct drvmgr_bus *bus;
        int size;

        /* The extra memory "service" is aligned to 4 bytes boundary. */
        size = ((sizeof(struct drvmgr_bus) + 3) & ~0x3) + extra;
        bus = (struct drvmgr_bus *)calloc(size, 1);
        if (!bus) {
                /* Failed to allocate device structure - critical error */
                rtems_fatal_error_occurred(RTEMS_NO_MEMORY);
        }
        *pbus = bus;
        bus->obj_type = DRVMGR_OBJ_BUS;

        return 0;
}

/* Add driver resources to a bus instance */
void drvmgr_bus_res_add(struct drvmgr_bus *bus,
                                struct drvmgr_bus_res *bres)
{
        /* insert first in bus resource list. Locking isn't needed since
         * resources can only be added before resource requests are made.
         * When bus has been registered resources are considered a read-only
         * tree.
         */
        bres->next = bus->reslist;
        bus->reslist = bres;
}

#ifdef RTEMS_DRVMGR_STARTUP

RTEMS_SYSINIT_ITEM(
  _DRV_Manager_initialization,
  RTEMS_SYSINIT_DRVMGR,
  RTEMS_SYSINIT_ORDER_MIDDLE
);

/* BSPs has already registered their "root bus" driver in the
 * bsp_predriver hook or so.
 *
 * Init Drivers to Level 1, constraints:
 *   - Interrupts and system clock timer does not work.
 *   - malloc() work, however other memory services may not
 *     have been initialized yet.
 *   - initializes most basic stuff
 *
 * Typical setup in Level 1:
 *   - Find most devices in system, do PCI scan and configuration.
 *   - Reset hardware if needed.
 *   - Install IRQ driver
 *   - Install Timer driver
 *   - Install console driver and debug printk()
 *   - Install extra memory.
 */
static void _DRV_Manager_init_level_1(void)
{
  _DRV_Manager_init_level(1);
}

RTEMS_SYSINIT_ITEM(
  _DRV_Manager_init_level_1,
  RTEMS_SYSINIT_DRVMGR_LEVEL_1,
  RTEMS_SYSINIT_ORDER_MIDDLE
);

/* Init Drivers to Level 2, constraints:
 *  - Interrupts can be registered and enabled.
 *  - System Clock is running
 *  - Console may be used.
 *
 * This is typically where drivers are initialized
 * for the first time.
 */
static void _DRV_Manager_init_level_2(void)
{
  _DRV_Manager_init_level(2);
}

RTEMS_SYSINIT_ITEM(
  _DRV_Manager_init_level_2,
  RTEMS_SYSINIT_DRVMGR_LEVEL_2,
  RTEMS_SYSINIT_ORDER_MIDDLE
);

/* Init Drivers to Level 3
 *
 * This is typically where normal drivers are initialized
 * for the second time, they may depend on other drivers
 * API inited in level 2
 */
static void _DRV_Manager_init_level_3(void)
{
  _DRV_Manager_init_level(3);
}

RTEMS_SYSINIT_ITEM(
  _DRV_Manager_init_level_3,
  RTEMS_SYSINIT_DRVMGR_LEVEL_3,
  RTEMS_SYSINIT_ORDER_MIDDLE
);

/* Init Drivers to Level 4,
 * Init drivers that depend on services initialized in Level 3
 */
static void _DRV_Manager_init_level_4(void)
{
  _DRV_Manager_init_level(4);
}

RTEMS_SYSINIT_ITEM(
  _DRV_Manager_init_level_4,
  RTEMS_SYSINIT_DRVMGR_LEVEL_4,
  RTEMS_SYSINIT_ORDER_MIDDLE
);

#endif /* RTEMS_DRVMGR_STARTUP */