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