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