drivers/misc/ibmasm/command.c

   1
   2 /*
   3  * IBM ASM Service Processor Device Driver
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  18  *
  19  * Copyright (C) IBM Corporation, 2004
  20  *
  21  * Author: Max Asböck <amax@us.ibm.com>
  22  *
  23  */
  24
  25 #include "ibmasm.h"
  26
  27 static void exec_next_command(struct service_processor *sp);
  28 static void free_command(struct kobject *kobj);
  29
  30 static struct kobj_type ibmasm_cmd_kobj_type = {
  31         .release = free_command,
  32 };
  33
  34
  35 struct command *ibmasm_new_command(size_t buffer_size)
  36 {
  37         struct command *cmd;
  38
  39         if (buffer_size > IBMASM_CMD_MAX_BUFFER_SIZE)
  40                 return NULL;
  41
  42         cmd = kmalloc(sizeof(struct command), GFP_KERNEL);
  43         if (cmd == NULL)
  44                 return NULL;
  45
  46         memset(cmd, 0, sizeof(*cmd));
  47
  48         cmd->buffer = kmalloc(buffer_size, GFP_KERNEL);
  49         if (cmd->buffer == NULL) {
  50                 kfree(cmd);
  51                 return NULL;
  52         }
  53         memset(cmd->buffer, 0, buffer_size);
  54         cmd->buffer_size = buffer_size;
  55
  56         kobject_init(&cmd->kobj);
  57         cmd->kobj.ktype = &ibmasm_cmd_kobj_type;
  58
  59         cmd->status = IBMASM_CMD_PENDING;
  60         init_waitqueue_head(&cmd->wait);
  61         INIT_LIST_HEAD(&cmd->queue_node);
  62
  63         return cmd;
  64 }
  65
  66 static void free_command(struct kobject *kobj)
  67 {
  68         struct command *cmd = to_command(kobj);
  69
  70         list_del(&cmd->queue_node);
  71         kfree(cmd->buffer);
  72         kfree(cmd);
  73 }
  74
  75 static void enqueue_command(struct service_processor *sp, struct command *cmd)
  76 {
  77         list_add_tail(&cmd->queue_node, &sp->command_queue);
  78 }
  79
  80 static struct command *dequeue_command(struct service_processor *sp)
  81 {
  82         struct command *cmd;
  83         struct list_head *next;
  84
  85         if (list_empty(&sp->command_queue))
  86                 return NULL;
  87
  88         next = sp->command_queue.next;
  89         list_del_init(next);
  90         cmd = list_entry(next, struct command, queue_node);
  91
  92         return cmd;
  93 }
  94
  95 static inline void do_exec_command(struct service_processor *sp)
  96 {
  97         if (ibmasm_send_i2o_message(sp)) {
  98                 sp->current_command->status = IBMASM_CMD_FAILED;
  99                 exec_next_command(sp);
 100         }
 101 }
 102
 103 /**
 104  * exec_command
 105  * send a command to a service processor
 106  * Commands are executed sequentially. One command (sp->current_command)
 107  * is sent to the service processor. Once the interrupt handler gets a
 108  * message of type command_response, the message is copied into
 109  * the current commands buffer,
 110  */
 111 void ibmasm_exec_command(struct service_processor *sp, struct command *cmd)
 112 {
 113         unsigned long flags;
 114
 115         spin_lock_irqsave(&sp->lock, flags);
 116
 117         if (!sp->current_command) {
 118                 command_get(cmd);
 119                 sp->current_command = cmd;
 120                 spin_unlock_irqrestore(&sp->lock, flags);
 121
 122                 do_exec_command(sp);
 123         } else {
 124                 enqueue_command(sp, cmd);
 125                 spin_unlock_irqrestore(&sp->lock, flags);
 126         }
 127 }
 128
 129 static void exec_next_command(struct service_processor *sp)
 130 {
 131         unsigned long flags;
 132
 133         wake_up(&sp->current_command->wait);
 134         command_put(sp->current_command);
 135
 136         spin_lock_irqsave(&sp->lock, flags);
 137         sp->current_command = dequeue_command(sp);
 138         if (sp->current_command) {
 139                 command_get(sp->current_command);
 140                 spin_unlock_irqrestore(&sp->lock, flags);
 141                 do_exec_command(sp);
 142         } else {
 143                 spin_unlock_irqrestore(&sp->lock, flags);
 144         }
 145 }
 146
 147 /**
 148  * Sleep until a command has failed or a response has been received
 149  * and the command status been updated by the interrupt handler.
 150  * (see receive_response).
 151  */
 152 void ibmasm_wait_for_response(struct command *cmd, int timeout)
 153 {
 154         wait_event_interruptible_timeout(cmd->wait,
 155                                 cmd->status == IBMASM_CMD_COMPLETE ||
 156                                 cmd->status == IBMASM_CMD_FAILED,
 157                                 timeout * HZ);
 158 }
 159
 160 /**
 161  * receive_command_response
 162  * called by the interrupt handler when a dot command of type command_response
 163  * was received.
 164  */
 165 void ibmasm_receive_command_response(struct service_processor *sp, void *response, size_t size)
 166 {
 167         struct command *cmd = sp->current_command;
 168
 169         if (!sp->current_command)
 170                 return;
 171
 172         memcpy(cmd->buffer, response, min(size, cmd->buffer_size));
 173         cmd->status = IBMASM_CMD_COMPLETE;
 174         exec_next_command(sp);
 175 }