/*      $NetBSD: subr_device.c,v 1.14 2024/08/27 13:44:55 thorpej Exp $ */

/*
* Copyright (c) 2006, 2021 The NetBSD Foundation, Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: subr_device.c,v 1.14 2024/08/27 13:44:55 thorpej Exp $");

#include <sys/param.h>
#include <sys/device.h>
#include <sys/device_impl.h>
#include <sys/systm.h>

#include <sys/device_calls.h>

/* Root device. */
device_t                        root_device;

/*
* devhandle_t accessors / mutators.
*/

static bool
devhandle_is_valid_internal(const devhandle_t * const handlep)
{
       if (handlep->impl == NULL) {
               return false;
       }
       return handlep->impl->type != DEVHANDLE_TYPE_INVALID;
}

bool
devhandle_is_valid(devhandle_t handle)
{
       return devhandle_is_valid_internal(&handle);
}

devhandle_t
devhandle_invalid(void)
{
       static const devhandle_t invalid_devhandle = {
               .impl = NULL,
               .uintptr = 0,
       };
       return invalid_devhandle;
}

devhandle_type_t
devhandle_type(devhandle_t handle)
{
       if (!devhandle_is_valid_internal(&handle)) {
               return DEVHANDLE_TYPE_INVALID;
       }

       return handle.impl->type;
}

int
devhandle_compare(devhandle_t handle1, devhandle_t handle2)
{
       devhandle_type_t type1 = devhandle_type(handle1);
       devhandle_type_t type2 = devhandle_type(handle2);

       if (type1 == DEVHANDLE_TYPE_INVALID) {
               return -1;
       }
       if (type2 == DEVHANDLE_TYPE_INVALID) {
               return 1;
       }

       if (type1 < type2) {
               return -1;
       }
       if (type1 > type2) {
               return 1;
       }

       /* For private handles, we also compare the impl pointers. */
       if (type1 == DEVHANDLE_TYPE_PRIVATE) {
               intptr_t impl1 = (intptr_t)handle1.impl;
               intptr_t impl2 = (intptr_t)handle2.impl;

               if (impl1 < impl2) {
                       return -1;
               }
               if (impl1 > impl2) {
                       return 1;
               }
       }

       if (handle1.integer < handle2.integer) {
               return -1;
       }
       if (handle1.integer > handle2.integer) {
               return 1;
       }

       return 0;
}

device_call_t
devhandle_lookup_device_call(devhandle_t handle, const char *name,
   devhandle_t *call_handlep)
{
       const struct devhandle_impl *impl;
       device_call_t call;

       /*
        * The back-end can override the handle to use for the call,
        * if needed.
        */
       *call_handlep = handle;

       for (impl = handle.impl; impl != NULL; impl = impl->super) {
               if (impl->lookup_device_call != NULL) {
                       call = impl->lookup_device_call(handle, name,
                           call_handlep);
                       if (call != NULL) {
                               return call;
                       }
               }
       }
       return NULL;
}

void
devhandle_impl_subclass(struct devhandle_impl *new_impl,
   const struct devhandle_impl *super,
   device_call_t (*new_lookup)(devhandle_t, const char *, devhandle_t *))
{
       new_impl->type = super->type;
       new_impl->super = super;
       new_impl->lookup_device_call = new_lookup;
}

/*
* Helper function that provides a short-hand method of the common
* "subclass a device handle" flow.
*/
devhandle_t
devhandle_subclass(devhandle_t handle,
   struct devhandle_impl *new_impl,
   device_call_t (*new_lookup)(devhandle_t, const char *, devhandle_t *))
{
       devhandle_impl_subclass(new_impl, handle.impl, new_lookup);
       handle.impl = new_impl;

       return handle;
}

/*
* Accessor functions for the device_t type.
*/

devclass_t
device_class(device_t dev)
{

       return dev->dv_class;
}

cfdata_t
device_cfdata(device_t dev)
{

       return dev->dv_cfdata;
}

cfdriver_t
device_cfdriver(device_t dev)
{

       return dev->dv_cfdriver;
}

cfattach_t
device_cfattach(device_t dev)
{

       return dev->dv_cfattach;
}

int
device_unit(device_t dev)
{

       return dev->dv_unit;
}

const char *
device_xname(device_t dev)
{

       return dev->dv_xname;
}

device_t
device_parent(device_t dev)
{

       return dev->dv_parent;
}

bool
device_activation(device_t dev, devact_level_t level)
{
       int active_flags;

       active_flags = DVF_ACTIVE;
       switch (level) {
       case DEVACT_LEVEL_FULL:
               active_flags |= DVF_CLASS_SUSPENDED;
               /*FALLTHROUGH*/
       case DEVACT_LEVEL_DRIVER:
               active_flags |= DVF_DRIVER_SUSPENDED;
               /*FALLTHROUGH*/
       case DEVACT_LEVEL_BUS:
               active_flags |= DVF_BUS_SUSPENDED;
               break;
       }

       return (dev->dv_flags & active_flags) == DVF_ACTIVE;
}

bool
device_is_active(device_t dev)
{
       int active_flags;

       active_flags = DVF_ACTIVE;
       active_flags |= DVF_CLASS_SUSPENDED;
       active_flags |= DVF_DRIVER_SUSPENDED;
       active_flags |= DVF_BUS_SUSPENDED;

       return (dev->dv_flags & active_flags) == DVF_ACTIVE;
}

bool
device_is_enabled(device_t dev)
{
       return (dev->dv_flags & DVF_ACTIVE) == DVF_ACTIVE;
}

bool
device_has_power(device_t dev)
{
       int active_flags;

       active_flags = DVF_ACTIVE | DVF_BUS_SUSPENDED;

       return (dev->dv_flags & active_flags) == DVF_ACTIVE;
}

int
device_locator(device_t dev, u_int locnum)
{

       KASSERT(dev->dv_locators != NULL);
       return dev->dv_locators[locnum];
}

void *
device_private(device_t dev)
{

       /*
        * The reason why device_private(NULL) is allowed is to simplify the
        * work of a lot of userspace request handlers (i.e., c/bdev
        * handlers) which grab cfdriver_t->cd_units[n].
        * It avoids having them test for it to be NULL and only then calling
        * device_private.
        */
       return dev == NULL ? NULL : dev->dv_private;
}

void
device_set_private(device_t dev, void *private)
{

       KASSERTMSG(dev->dv_private == NULL, "device_set_private(%p, %p):"
           " device %s already has private set to %p",
           dev, private, device_xname(dev), device_private(dev));
       KASSERT(private != NULL);
       dev->dv_private = private;
}

prop_dictionary_t
device_properties(device_t dev)
{

       return dev->dv_properties;
}

/*
* device_is_a:
*
*      Returns true if the device is an instance of the specified
*      driver.
*/
bool
device_is_a(device_t dev, const char *dname)
{
       if (dev == NULL || dev->dv_cfdriver == NULL) {
               return false;
       }

       return strcmp(dev->dv_cfdriver->cd_name, dname) == 0;
}

/*
* device_attached_to_iattr:
*
*      Returns true if the device attached to the specified interface
*      attribute.
*/
bool
device_attached_to_iattr(device_t dev, const char *iattr)
{
       cfdata_t cfdata = device_cfdata(dev);
       const struct cfparent *pspec;

       if (cfdata == NULL || (pspec = cfdata->cf_pspec) == NULL) {
               return false;
       }

       return strcmp(pspec->cfp_iattr, iattr) == 0;
}

void
device_set_handle(device_t dev, devhandle_t handle)
{
       dev->dv_handle = handle;
}

devhandle_t
device_handle(device_t dev)
{
       return dev->dv_handle;
}

int
device_call_generic(device_t dev, devhandle_t handle,
   const struct device_call_generic *gen)
{
       device_call_t call;
       devhandle_t call_handle;

       call = devhandle_lookup_device_call(handle, gen->name, &call_handle);
       if (call == NULL) {
               return ENOTSUP;
       }
       return call(dev, call_handle, gen->args);
}

int
device_enumerate_children(device_t dev,
   bool (*callback)(device_t, devhandle_t, void *),
   void *callback_arg)
{
       struct device_enumerate_children_args args = {
               .callback = callback,
               .callback_arg = callback_arg,
       };

       return device_call(dev, DEVICE_ENUMERATE_CHILDREN(&args));
}

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