drivers/scsi/isci/state_machine.c

   1 /*
   2  * This file is provided under a dual BSD/GPLv2 license.  When using or
   3  * redistributing this file, you may do so under either license.
   4  *
   5  * GPL LICENSE SUMMARY
   6  *
   7  * Copyright(c) 2008 - 2011 Intel Corporation. All rights reserved.
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of version 2 of the GNU General Public License as
  11  * published by the Free Software Foundation.
  12  *
  13  * This program is distributed in the hope that it will be useful, but
  14  * WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
  21  * The full GNU General Public License is included in this distribution
  22  * in the file called LICENSE.GPL.
  23  *
  24  * BSD LICENSE
  25  *
  26  * Copyright(c) 2008 - 2011 Intel Corporation. All rights reserved.
  27  * All rights reserved.
  28  *
  29  * Redistribution and use in source and binary forms, with or without
  30  * modification, are permitted provided that the following conditions
  31  * are met:
  32  *
  33  *   * Redistributions of source code must retain the above copyright
  34  *     notice, this list of conditions and the following disclaimer.
  35  *   * Redistributions in binary form must reproduce the above copyright
  36  *     notice, this list of conditions and the following disclaimer in
  37  *     the documentation and/or other materials provided with the
  38  *     distribution.
  39  *   * Neither the name of Intel Corporation nor the names of its
  40  *     contributors may be used to endorse or promote products derived
  41  *     from this software without specific prior written permission.
  42  *
  43  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  44  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  45  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  46  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  47  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  48  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  49  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  50  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  51  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  52  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  53  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  54  */
  55
  56 /**
  57  * This file contains all of the functionality common to all state machine
  58  *    object implementations.
  59  *
  60  *
  61  */
  62
  63 #include "state_machine.h"
  64
  65 static void sci_state_machine_exit_state(struct sci_base_state_machine *sm)
  66 {
  67         u32 state = sm->current_state_id;
  68         sci_state_transition_t exit = sm->state_table[state].exit_state;
  69
  70         if (exit)
  71                 exit(sm->state_machine_owner);
  72 }
  73
  74 static void sci_state_machine_enter_state(struct sci_base_state_machine *sm)
  75 {
  76         u32 state = sm->current_state_id;
  77         sci_state_transition_t enter = sm->state_table[state].enter_state;
  78
  79         if (enter)
  80                 enter(sm->state_machine_owner);
  81 }
  82
  83 /*
  84  * ******************************************************************************
  85  * * P R O T E C T E D    M E T H O D S
  86  * ****************************************************************************** */
  87
  88 /**
  89  * This method will set the initial state and state table for the state
  90  *    machine. The caller should follow this request with the initialize
  91  *    request to cause the state machine to start.
  92  * @sm: This parameter provides the state machine object to be
  93  *    constructed.
  94  * @state_machine_owner: This parameter indicates the object that is owns the
  95  *    state machine being constructed.
  96  * @state_table: This parameter specifies the table of state objects that is
  97  *    managed by this state machine.
  98  * @initial_state: This parameter specifies the value of the initial state for
  99  *    this state machine.
 100  *
 101  */
 102 void sci_base_state_machine_construct(struct sci_base_state_machine *sm,
 103                                       void *owner,
 104                                       const struct sci_base_state *state_table,
 105                                       u32 initial_state)
 106 {
 107         sm->state_machine_owner = owner;
 108         sm->initial_state_id    = initial_state;
 109         sm->previous_state_id   = initial_state;
 110         sm->current_state_id    = initial_state;
 111         sm->state_table         = state_table;
 112 }
 113
 114 /**
 115  * This method will cause the state machine to enter the initial state.
 116  * @sm: This parameter specifies the state machine that is to
 117  *    be started.
 118  *
 119  * sci_base_state_machine_construct() for how to set the initial state none
 120  */
 121 void sci_base_state_machine_start(struct sci_base_state_machine *sm)
 122 {
 123         sm->current_state_id = sm->initial_state_id;
 124         sci_state_machine_enter_state(sm);
 125 }
 126
 127 /**
 128  * This method will cause the state machine to exit it's current state only.
 129  * @sm: This parameter specifies the state machine that is to
 130  *    be stopped.
 131  *
 132  */
 133 void sci_base_state_machine_stop(
 134         struct sci_base_state_machine *sm)
 135 {
 136         sci_state_machine_exit_state(sm);
 137 }
 138
 139 /**
 140  * This method performs an update to the current state of the state machine.
 141  * @sm: This parameter specifies the state machine for which
 142  *    the caller wishes to perform a state change.
 143  * @next_state: This parameter specifies the new state for the state machine.
 144  *
 145  */
 146 void sci_base_state_machine_change_state(
 147         struct sci_base_state_machine *sm,
 148         u32 next_state)
 149 {
 150         sci_state_machine_exit_state(sm);
 151
 152         sm->previous_state_id = sm->current_state_id;
 153         sm->current_state_id = next_state;
 154
 155         sci_state_machine_enter_state(sm);
 156 }
 157
 158 /**
 159  * This method simply returns the current state of the state machine to the
 160  *    caller.
 161  * @sm: This parameter specifies the state machine for which to
 162  *    retrieve the current state.
 163  *
 164  * This method returns a u32 value indicating the current state for the
 165  * supplied state machine.
 166  */
 167 u32 sci_base_state_machine_get_state(struct sci_base_state_machine *sm)
 168 {
 169         return sm->current_state_id;
 170 }
 171