Merge branch 'linux-next' of git://git.infradead.org/ubifs-2.6
[linux-2.6] / arch / powerpc / sysdev / pmi.c
1 /*
2  * pmi driver
3  *
4  * (C) Copyright IBM Deutschland Entwicklung GmbH 2005
5  *
6  * PMI (Platform Management Interrupt) is a way to communicate
7  * with the BMC (Baseboard Management Controller) via interrupts.
8  * Unlike IPMI it is bidirectional and has a low latency.
9  *
10  * Author: Christian Krafft <krafft@de.ibm.com>
11  *
12  * This program is free software; you can redistribute it and/or modify
13  * it under the terms of the GNU General Public License as published by
14  * the Free Software Foundation; either version 2, or (at your option)
15  * any later version.
16  *
17  * This program is distributed in the hope that it will be useful,
18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
20  * GNU General Public License for more details.
21  *
22  * You should have received a copy of the GNU General Public License
23  * along with this program; if not, write to the Free Software
24  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
25  */
26
27 #include <linux/interrupt.h>
28 #include <linux/completion.h>
29 #include <linux/spinlock.h>
30 #include <linux/workqueue.h>
31 #include <linux/of_device.h>
32 #include <linux/of_platform.h>
33
34 #include <asm/io.h>
35 #include <asm/pmi.h>
36 #include <asm/prom.h>
37
38 struct pmi_data {
39         struct list_head        handler;
40         spinlock_t              handler_spinlock;
41         spinlock_t              pmi_spinlock;
42         struct mutex            msg_mutex;
43         pmi_message_t           msg;
44         struct completion       *completion;
45         struct of_device        *dev;
46         int                     irq;
47         u8 __iomem              *pmi_reg;
48         struct work_struct      work;
49 };
50
51 static struct pmi_data *data;
52
53 static int pmi_irq_handler(int irq, void *dev_id)
54 {
55         u8 type;
56         int rc;
57
58         spin_lock(&data->pmi_spinlock);
59
60         type = ioread8(data->pmi_reg + PMI_READ_TYPE);
61         pr_debug("pmi: got message of type %d\n", type);
62
63         if (type & PMI_ACK && !data->completion) {
64                 printk(KERN_WARNING "pmi: got unexpected ACK message.\n");
65                 rc = -EIO;
66                 goto unlock;
67         }
68
69         if (data->completion && !(type & PMI_ACK)) {
70                 printk(KERN_WARNING "pmi: expected ACK, but got %d\n", type);
71                 rc = -EIO;
72                 goto unlock;
73         }
74
75         data->msg.type = type;
76         data->msg.data0 = ioread8(data->pmi_reg + PMI_READ_DATA0);
77         data->msg.data1 = ioread8(data->pmi_reg + PMI_READ_DATA1);
78         data->msg.data2 = ioread8(data->pmi_reg + PMI_READ_DATA2);
79         rc = 0;
80 unlock:
81         spin_unlock(&data->pmi_spinlock);
82
83         if (rc == -EIO) {
84                 rc = IRQ_HANDLED;
85                 goto out;
86         }
87
88         if (data->msg.type & PMI_ACK) {
89                 complete(data->completion);
90                 rc = IRQ_HANDLED;
91                 goto out;
92         }
93
94         schedule_work(&data->work);
95
96         rc = IRQ_HANDLED;
97 out:
98         return rc;
99 }
100
101
102 static struct of_device_id pmi_match[] = {
103         { .type = "ibm,pmi", .name = "ibm,pmi" },
104         { .type = "ibm,pmi" },
105         {},
106 };
107
108 MODULE_DEVICE_TABLE(of, pmi_match);
109
110 static void pmi_notify_handlers(struct work_struct *work)
111 {
112         struct pmi_handler *handler;
113
114         spin_lock(&data->handler_spinlock);
115         list_for_each_entry(handler, &data->handler, node) {
116                 pr_debug(KERN_INFO "pmi: notifying handler %p\n", handler);
117                 if (handler->type == data->msg.type)
118                         handler->handle_pmi_message(data->msg);
119         }
120         spin_unlock(&data->handler_spinlock);
121 }
122
123 static int pmi_of_probe(struct of_device *dev,
124                         const struct of_device_id *match)
125 {
126         struct device_node *np = dev->node;
127         int rc;
128
129         if (data) {
130                 printk(KERN_ERR "pmi: driver has already been initialized.\n");
131                 rc = -EBUSY;
132                 goto out;
133         }
134
135         data = kzalloc(sizeof(struct pmi_data), GFP_KERNEL);
136         if (!data) {
137                 printk(KERN_ERR "pmi: could not allocate memory.\n");
138                 rc = -ENOMEM;
139                 goto out;
140         }
141
142         data->pmi_reg = of_iomap(np, 0);
143         if (!data->pmi_reg) {
144                 printk(KERN_ERR "pmi: invalid register address.\n");
145                 rc = -EFAULT;
146                 goto error_cleanup_data;
147         }
148
149         INIT_LIST_HEAD(&data->handler);
150
151         mutex_init(&data->msg_mutex);
152         spin_lock_init(&data->pmi_spinlock);
153         spin_lock_init(&data->handler_spinlock);
154
155         INIT_WORK(&data->work, pmi_notify_handlers);
156
157         data->dev = dev;
158
159         data->irq = irq_of_parse_and_map(np, 0);
160         if (data->irq == NO_IRQ) {
161                 printk(KERN_ERR "pmi: invalid interrupt.\n");
162                 rc = -EFAULT;
163                 goto error_cleanup_iomap;
164         }
165
166         rc = request_irq(data->irq, pmi_irq_handler, 0, "pmi", NULL);
167         if (rc) {
168                 printk(KERN_ERR "pmi: can't request IRQ %d: returned %d\n",
169                                 data->irq, rc);
170                 goto error_cleanup_iomap;
171         }
172
173         printk(KERN_INFO "pmi: found pmi device at addr %p.\n", data->pmi_reg);
174
175         goto out;
176
177 error_cleanup_iomap:
178         iounmap(data->pmi_reg);
179
180 error_cleanup_data:
181         kfree(data);
182
183 out:
184         return rc;
185 }
186
187 static int pmi_of_remove(struct of_device *dev)
188 {
189         struct pmi_handler *handler, *tmp;
190
191         free_irq(data->irq, NULL);
192         iounmap(data->pmi_reg);
193
194         spin_lock(&data->handler_spinlock);
195
196         list_for_each_entry_safe(handler, tmp, &data->handler, node)
197                 list_del(&handler->node);
198
199         spin_unlock(&data->handler_spinlock);
200
201         kfree(data);
202         data = NULL;
203
204         return 0;
205 }
206
207 static struct of_platform_driver pmi_of_platform_driver = {
208         .match_table    = pmi_match,
209         .probe          = pmi_of_probe,
210         .remove         = pmi_of_remove,
211         .driver         = {
212                 .name   = "pmi",
213         },
214 };
215
216 static int __init pmi_module_init(void)
217 {
218         return of_register_platform_driver(&pmi_of_platform_driver);
219 }
220 module_init(pmi_module_init);
221
222 static void __exit pmi_module_exit(void)
223 {
224         of_unregister_platform_driver(&pmi_of_platform_driver);
225 }
226 module_exit(pmi_module_exit);
227
228 int pmi_send_message(pmi_message_t msg)
229 {
230         unsigned long flags;
231         DECLARE_COMPLETION_ONSTACK(completion);
232
233         if (!data)
234                 return -ENODEV;
235
236         mutex_lock(&data->msg_mutex);
237
238         data->msg = msg;
239         pr_debug("pmi_send_message: msg is %08x\n", *(u32*)&msg);
240
241         data->completion = &completion;
242
243         spin_lock_irqsave(&data->pmi_spinlock, flags);
244         iowrite8(msg.data0, data->pmi_reg + PMI_WRITE_DATA0);
245         iowrite8(msg.data1, data->pmi_reg + PMI_WRITE_DATA1);
246         iowrite8(msg.data2, data->pmi_reg + PMI_WRITE_DATA2);
247         iowrite8(msg.type, data->pmi_reg + PMI_WRITE_TYPE);
248         spin_unlock_irqrestore(&data->pmi_spinlock, flags);
249
250         pr_debug("pmi_send_message: wait for completion\n");
251
252         wait_for_completion_interruptible_timeout(data->completion,
253                                                   PMI_TIMEOUT);
254
255         data->completion = NULL;
256
257         mutex_unlock(&data->msg_mutex);
258
259         return 0;
260 }
261 EXPORT_SYMBOL_GPL(pmi_send_message);
262
263 int pmi_register_handler(struct pmi_handler *handler)
264 {
265         if (!data)
266                 return -ENODEV;
267
268         spin_lock(&data->handler_spinlock);
269         list_add_tail(&handler->node, &data->handler);
270         spin_unlock(&data->handler_spinlock);
271
272         return 0;
273 }
274 EXPORT_SYMBOL_GPL(pmi_register_handler);
275
276 void pmi_unregister_handler(struct pmi_handler *handler)
277 {
278         if (!data)
279                 return;
280
281         pr_debug("pmi: unregistering handler %p\n", handler);
282
283         spin_lock(&data->handler_spinlock);
284         list_del(&handler->node);
285         spin_unlock(&data->handler_spinlock);
286 }
287 EXPORT_SYMBOL_GPL(pmi_unregister_handler);
288
289 MODULE_LICENSE("GPL");
290 MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>");
291 MODULE_DESCRIPTION("IBM Platform Management Interrupt driver");