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 #include "lowlevel.h"
  27
  28 static void exec_next_command(struct service_processor *sp);
  29 static void free_command(struct kobject *kobj);
  30
  31 static struct kobj_type ibmasm_cmd_kobj_type = {
  32         .release = free_command,
  33 };
  34
  35 static atomic_t command_count = ATOMIC_INIT(0);
  36
  37 struct command *ibmasm_new_command(struct service_processor *sp, size_t buffer_size)
  38 {
  39         struct command *cmd;
  40
  41         if (buffer_size > IBMASM_CMD_MAX_BUFFER_SIZE)
  42                 return NULL;
  43
  44         cmd = kzalloc(sizeof(struct command), GFP_KERNEL);
  45         if (cmd == NULL)
  46                 return NULL;
  47
  48
  49         cmd->buffer = kzalloc(buffer_size, GFP_KERNEL);
  50         if (cmd->buffer == NULL) {
  51                 kfree(cmd);
  52                 return NULL;
  53         }
  54         cmd->buffer_size = buffer_size;
  55
  56         kobject_init(&cmd->kobj);
  57         cmd->kobj.ktype = &ibmasm_cmd_kobj_type;
  58         cmd->lock = &sp->lock;
  59
  60         cmd->status = IBMASM_CMD_PENDING;
  61         init_waitqueue_head(&cmd->wait);
  62         INIT_LIST_HEAD(&cmd->queue_node);
  63
  64         atomic_inc(&command_count);
  65         dbg("command count: %d\n", atomic_read(&command_count));
  66
  67         return cmd;
  68 }
  69
  70 static void free_command(struct kobject *kobj)
  71 {
  72         struct command *cmd = to_command(kobj);
  73
  74         list_del(&cmd->queue_node);
  75         atomic_dec(&command_count);
  76         dbg("command count: %d\n", atomic_read(&command_count));
  77         kfree(cmd->buffer);
  78         kfree(cmd);
  79 }
  80
  81 static void enqueue_command(struct service_processor *sp, struct command *cmd)
  82 {
  83         list_add_tail(&cmd->queue_node, &sp->command_queue);
  84 }
  85
  86 static struct command *dequeue_command(struct service_processor *sp)
  87 {
  88         struct command *cmd;
  89         struct list_head *next;
  90
  91         if (list_empty(&sp->command_queue))
  92                 return NULL;
  93
  94         next = sp->command_queue.next;
  95         list_del_init(next);
  96         cmd = list_entry(next, struct command, queue_node);
  97
  98         return cmd;
  99 }
 100
 101 static inline void do_exec_command(struct service_processor *sp)
 102 {
 103         char tsbuf[32];
 104
 105         dbg("%s:%d at %s\n", __FUNCTION__, __LINE__, get_timestamp(tsbuf));
 106
 107         if (ibmasm_send_i2o_message(sp)) {
 108                 sp->current_command->status = IBMASM_CMD_FAILED;
 109                 wake_up(&sp->current_command->wait);
 110                 command_put(sp->current_command);
 111                 exec_next_command(sp);
 112         }
 113 }
 114
 115 /**
 116  * exec_command
 117  * send a command to a service processor
 118  * Commands are executed sequentially. One command (sp->current_command)
 119  * is sent to the service processor. Once the interrupt handler gets a
 120  * message of type command_response, the message is copied into
 121  * the current commands buffer,
 122  */
 123 void ibmasm_exec_command(struct service_processor *sp, struct command *cmd)
 124 {
 125         unsigned long flags;
 126         char tsbuf[32];
 127
 128         dbg("%s:%d at %s\n", __FUNCTION__, __LINE__, get_timestamp(tsbuf));
 129
 130         spin_lock_irqsave(&sp->lock, flags);
 131
 132         if (!sp->current_command) {
 133                 sp->current_command = cmd;
 134                 command_get(sp->current_command);
 135                 spin_unlock_irqrestore(&sp->lock, flags);
 136                 do_exec_command(sp);
 137         } else {
 138                 enqueue_command(sp, cmd);
 139                 spin_unlock_irqrestore(&sp->lock, flags);
 140         }
 141 }
 142
 143 static void exec_next_command(struct service_processor *sp)
 144 {
 145         unsigned long flags;
 146         char tsbuf[32];
 147
 148         dbg("%s:%d at %s\n", __FUNCTION__, __LINE__, get_timestamp(tsbuf));
 149
 150         spin_lock_irqsave(&sp->lock, flags);
 151         sp->current_command = dequeue_command(sp);
 152         if (sp->current_command) {
 153                 command_get(sp->current_command);
 154                 spin_unlock_irqrestore(&sp->lock, flags);
 155                 do_exec_command(sp);
 156         } else {
 157                 spin_unlock_irqrestore(&sp->lock, flags);
 158         }
 159 }
 160
 161 /**
 162  * Sleep until a command has failed or a response has been received
 163  * and the command status been updated by the interrupt handler.
 164  * (see receive_response).
 165  */
 166 void ibmasm_wait_for_response(struct command *cmd, int timeout)
 167 {
 168         wait_event_interruptible_timeout(cmd->wait,
 169                                 cmd->status == IBMASM_CMD_COMPLETE ||
 170                                 cmd->status == IBMASM_CMD_FAILED,
 171                                 timeout * HZ);
 172 }
 173
 174 /**
 175  * receive_command_response
 176  * called by the interrupt handler when a dot command of type command_response
 177  * was received.
 178  */
 179 void ibmasm_receive_command_response(struct service_processor *sp, void *response, size_t size)
 180 {
 181         struct command *cmd = sp->current_command;
 182
 183         if (!sp->current_command)
 184                 return;
 185
 186         memcpy_fromio(cmd->buffer, response, min(size, cmd->buffer_size));
 187         cmd->status = IBMASM_CMD_COMPLETE;
 188         wake_up(&sp->current_command->wait);
 189         command_put(sp->current_command);
 190         exec_next_command(sp);
 191 }