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 = kmalloc(sizeof(struct command), GFP_KERNEL);
  45         if (cmd == NULL)
  46                 return NULL;
  47
  48         memset(cmd, 0, sizeof(*cmd));
  49
  50         cmd->buffer = kmalloc(buffer_size, GFP_KERNEL);
  51         if (cmd->buffer == NULL) {
  52                 kfree(cmd);
  53                 return NULL;
  54         }
  55         memset(cmd->buffer, 0, buffer_size);
  56         cmd->buffer_size = buffer_size;
  57
  58         kobject_init(&cmd->kobj);
  59         cmd->kobj.ktype = &ibmasm_cmd_kobj_type;
  60         cmd->lock = &sp->lock;
  61
  62         cmd->status = IBMASM_CMD_PENDING;
  63         init_waitqueue_head(&cmd->wait);
  64         INIT_LIST_HEAD(&cmd->queue_node);
  65
  66         atomic_inc(&command_count);
  67         dbg("command count: %d\n", atomic_read(&command_count));
  68
  69         return cmd;
  70 }
  71
  72 static void free_command(struct kobject *kobj)
  73 {
  74         struct command *cmd = to_command(kobj);
  75
  76         list_del(&cmd->queue_node);
  77         atomic_dec(&command_count);
  78         dbg("command count: %d\n", atomic_read(&command_count));
  79         kfree(cmd->buffer);
  80         kfree(cmd);
  81 }
  82
  83 static void enqueue_command(struct service_processor *sp, struct command *cmd)
  84 {
  85         list_add_tail(&cmd->queue_node, &sp->command_queue);
  86 }
  87
  88 static struct command *dequeue_command(struct service_processor *sp)
  89 {
  90         struct command *cmd;
  91         struct list_head *next;
  92
  93         if (list_empty(&sp->command_queue))
  94                 return NULL;
  95
  96         next = sp->command_queue.next;
  97         list_del_init(next);
  98         cmd = list_entry(next, struct command, queue_node);
  99
 100         return cmd;
 101 }
 102
 103 static inline void do_exec_command(struct service_processor *sp)
 104 {
 105         char tsbuf[32];
 106
 107         dbg("%s:%d at %s\n", __FUNCTION__, __LINE__, get_timestamp(tsbuf));
 108
 109         if (ibmasm_send_i2o_message(sp)) {
 110                 sp->current_command->status = IBMASM_CMD_FAILED;
 111                 wake_up(&sp->current_command->wait);
 112                 command_put(sp->current_command);
 113                 exec_next_command(sp);
 114         }
 115 }
 116
 117 /**
 118  * exec_command
 119  * send a command to a service processor
 120  * Commands are executed sequentially. One command (sp->current_command)
 121  * is sent to the service processor. Once the interrupt handler gets a
 122  * message of type command_response, the message is copied into
 123  * the current commands buffer,
 124  */
 125 void ibmasm_exec_command(struct service_processor *sp, struct command *cmd)
 126 {
 127         unsigned long flags;
 128         char tsbuf[32];
 129
 130         dbg("%s:%d at %s\n", __FUNCTION__, __LINE__, get_timestamp(tsbuf));
 131
 132         spin_lock_irqsave(&sp->lock, flags);
 133
 134         if (!sp->current_command) {
 135                 sp->current_command = cmd;
 136                 command_get(sp->current_command);
 137                 spin_unlock_irqrestore(&sp->lock, flags);
 138                 do_exec_command(sp);
 139         } else {
 140                 enqueue_command(sp, cmd);
 141                 spin_unlock_irqrestore(&sp->lock, flags);
 142         }
 143 }
 144
 145 static void exec_next_command(struct service_processor *sp)
 146 {
 147         unsigned long flags;
 148         char tsbuf[32];
 149
 150         dbg("%s:%d at %s\n", __FUNCTION__, __LINE__, get_timestamp(tsbuf));
 151
 152         spin_lock_irqsave(&sp->lock, flags);
 153         sp->current_command = dequeue_command(sp);
 154         if (sp->current_command) {
 155                 command_get(sp->current_command);
 156                 spin_unlock_irqrestore(&sp->lock, flags);
 157                 do_exec_command(sp);
 158         } else {
 159                 spin_unlock_irqrestore(&sp->lock, flags);
 160         }
 161 }
 162
 163 /**
 164  * Sleep until a command has failed or a response has been received
 165  * and the command status been updated by the interrupt handler.
 166  * (see receive_response).
 167  */
 168 void ibmasm_wait_for_response(struct command *cmd, int timeout)
 169 {
 170         wait_event_interruptible_timeout(cmd->wait,
 171                                 cmd->status == IBMASM_CMD_COMPLETE ||
 172                                 cmd->status == IBMASM_CMD_FAILED,
 173                                 timeout * HZ);
 174 }
 175
 176 /**
 177  * receive_command_response
 178  * called by the interrupt handler when a dot command of type command_response
 179  * was received.
 180  */
 181 void ibmasm_receive_command_response(struct service_processor *sp, void *response, size_t size)
 182 {
 183         struct command *cmd = sp->current_command;
 184
 185         if (!sp->current_command)
 186                 return;
 187
 188         memcpy_fromio(cmd->buffer, response, min(size, cmd->buffer_size));
 189         cmd->status = IBMASM_CMD_COMPLETE;
 190         wake_up(&sp->current_command->wait);
 191         command_put(sp->current_command);
 192         exec_next_command(sp);
 193 }