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