Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux...
[linux-2.6] / 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 }