Merge branch 'linus' into sched/core
[linux-3.10.git] / 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/slab.h>
29 #include <linux/completion.h>
30 #include <linux/spinlock.h>
31 #include <linux/workqueue.h>
32 #include <linux/of_device.h>
33 #include <linux/of_platform.h>
34
35 #include <asm/io.h>
36 #include <asm/pmi.h>
37 #include <asm/prom.h>
38
39 struct pmi_data {
40         struct list_head        handler;
41         spinlock_t              handler_spinlock;
42         spinlock_t              pmi_spinlock;
43         struct mutex            msg_mutex;
44         pmi_message_t           msg;
45         struct completion       *completion;
46         struct of_device        *dev;
47         int                     irq;
48         u8 __iomem              *pmi_reg;
49         struct work_struct      work;
50 };
51
52 static struct pmi_data *data;
53
54 static irqreturn_t pmi_irq_handler(int irq, void *dev_id)
55 {
56         u8 type;
57         int rc;
58
59         spin_lock(&data->pmi_spinlock);
60
61         type = ioread8(data->pmi_reg + PMI_READ_TYPE);
62         pr_debug("pmi: got message of type %d\n", type);
63
64         if (type & PMI_ACK && !data->completion) {
65                 printk(KERN_WARNING "pmi: got unexpected ACK message.\n");
66                 rc = -EIO;
67                 goto unlock;
68         }
69
70         if (data->completion && !(type & PMI_ACK)) {
71                 printk(KERN_WARNING "pmi: expected ACK, but got %d\n", type);
72                 rc = -EIO;
73                 goto unlock;
74         }
75
76         data->msg.type = type;
77         data->msg.data0 = ioread8(data->pmi_reg + PMI_READ_DATA0);
78         data->msg.data1 = ioread8(data->pmi_reg + PMI_READ_DATA1);
79         data->msg.data2 = ioread8(data->pmi_reg + PMI_READ_DATA2);
80         rc = 0;
81 unlock:
82         spin_unlock(&data->pmi_spinlock);
83
84         if (rc == -EIO) {
85                 rc = IRQ_HANDLED;
86                 goto out;
87         }
88
89         if (data->msg.type & PMI_ACK) {
90                 complete(data->completion);
91                 rc = IRQ_HANDLED;
92                 goto out;
93         }
94
95         schedule_work(&data->work);
96
97         rc = IRQ_HANDLED;
98 out:
99         return rc;
100 }
101
102
103 static struct of_device_id pmi_match[] = {
104         { .type = "ibm,pmi", .name = "ibm,pmi" },
105         { .type = "ibm,pmi" },
106         {},
107 };
108
109 MODULE_DEVICE_TABLE(of, pmi_match);
110
111 static void pmi_notify_handlers(struct work_struct *work)
112 {
113         struct pmi_handler *handler;
114
115         spin_lock(&data->handler_spinlock);
116         list_for_each_entry(handler, &data->handler, node) {
117                 pr_debug(KERN_INFO "pmi: notifying handler %p\n", handler);
118                 if (handler->type == data->msg.type)
119                         handler->handle_pmi_message(data->msg);
120         }
121         spin_unlock(&data->handler_spinlock);
122 }
123
124 static int pmi_of_probe(struct of_device *dev,
125                         const struct of_device_id *match)
126 {
127         struct device_node *np = dev->node;
128         int rc;
129
130         if (data) {
131                 printk(KERN_ERR "pmi: driver has already been initialized.\n");
132                 rc = -EBUSY;
133                 goto out;
134         }
135
136         data = kzalloc(sizeof(struct pmi_data), GFP_KERNEL);
137         if (!data) {
138                 printk(KERN_ERR "pmi: could not allocate memory.\n");
139                 rc = -ENOMEM;
140                 goto out;
141         }
142
143         data->pmi_reg = of_iomap(np, 0);
144         if (!data->pmi_reg) {
145                 printk(KERN_ERR "pmi: invalid register address.\n");
146                 rc = -EFAULT;
147                 goto error_cleanup_data;
148         }
149
150         INIT_LIST_HEAD(&data->handler);
151
152         mutex_init(&data->msg_mutex);
153         spin_lock_init(&data->pmi_spinlock);
154         spin_lock_init(&data->handler_spinlock);
155
156         INIT_WORK(&data->work, pmi_notify_handlers);
157
158         data->dev = dev;
159
160         data->irq = irq_of_parse_and_map(np, 0);
161         if (data->irq == NO_IRQ) {
162                 printk(KERN_ERR "pmi: invalid interrupt.\n");
163                 rc = -EFAULT;
164                 goto error_cleanup_iomap;
165         }
166
167         rc = request_irq(data->irq, pmi_irq_handler, 0, "pmi", NULL);
168         if (rc) {
169                 printk(KERN_ERR "pmi: can't request IRQ %d: returned %d\n",
170                                 data->irq, rc);
171                 goto error_cleanup_iomap;
172         }
173
174         printk(KERN_INFO "pmi: found pmi device at addr %p.\n", data->pmi_reg);
175
176         goto out;
177
178 error_cleanup_iomap:
179         iounmap(data->pmi_reg);
180
181 error_cleanup_data:
182         kfree(data);
183
184 out:
185         return rc;
186 }
187
188 static int pmi_of_remove(struct of_device *dev)
189 {
190         struct pmi_handler *handler, *tmp;
191
192         free_irq(data->irq, NULL);
193         iounmap(data->pmi_reg);
194
195         spin_lock(&data->handler_spinlock);
196
197         list_for_each_entry_safe(handler, tmp, &data->handler, node)
198                 list_del(&handler->node);
199
200         spin_unlock(&data->handler_spinlock);
201
202         kfree(data);
203         data = NULL;
204
205         return 0;
206 }
207
208 static struct of_platform_driver pmi_of_platform_driver = {
209         .match_table    = pmi_match,
210         .probe          = pmi_of_probe,
211         .remove         = pmi_of_remove,
212         .driver         = {
213                 .name   = "pmi",
214         },
215 };
216
217 static int __init pmi_module_init(void)
218 {
219         return of_register_platform_driver(&pmi_of_platform_driver);
220 }
221 module_init(pmi_module_init);
222
223 static void __exit pmi_module_exit(void)
224 {
225         of_unregister_platform_driver(&pmi_of_platform_driver);
226 }
227 module_exit(pmi_module_exit);
228
229 int pmi_send_message(pmi_message_t msg)
230 {
231         unsigned long flags;
232         DECLARE_COMPLETION_ONSTACK(completion);
233
234         if (!data)
235                 return -ENODEV;
236
237         mutex_lock(&data->msg_mutex);
238
239         data->msg = msg;
240         pr_debug("pmi_send_message: msg is %08x\n", *(u32*)&msg);
241
242         data->completion = &completion;
243
244         spin_lock_irqsave(&data->pmi_spinlock, flags);
245         iowrite8(msg.data0, data->pmi_reg + PMI_WRITE_DATA0);
246         iowrite8(msg.data1, data->pmi_reg + PMI_WRITE_DATA1);
247         iowrite8(msg.data2, data->pmi_reg + PMI_WRITE_DATA2);
248         iowrite8(msg.type, data->pmi_reg + PMI_WRITE_TYPE);
249         spin_unlock_irqrestore(&data->pmi_spinlock, flags);
250
251         pr_debug("pmi_send_message: wait for completion\n");
252
253         wait_for_completion_interruptible_timeout(data->completion,
254                                                   PMI_TIMEOUT);
255
256         data->completion = NULL;
257
258         mutex_unlock(&data->msg_mutex);
259
260         return 0;
261 }
262 EXPORT_SYMBOL_GPL(pmi_send_message);
263
264 int pmi_register_handler(struct pmi_handler *handler)
265 {
266         if (!data)
267                 return -ENODEV;
268
269         spin_lock(&data->handler_spinlock);
270         list_add_tail(&handler->node, &data->handler);
271         spin_unlock(&data->handler_spinlock);
272
273         return 0;
274 }
275 EXPORT_SYMBOL_GPL(pmi_register_handler);
276
277 void pmi_unregister_handler(struct pmi_handler *handler)
278 {
279         if (!data)
280                 return;
281
282         pr_debug("pmi: unregistering handler %p\n", handler);
283
284         spin_lock(&data->handler_spinlock);
285         list_del(&handler->node);
286         spin_unlock(&data->handler_spinlock);
287 }
288 EXPORT_SYMBOL_GPL(pmi_unregister_handler);
289
290 MODULE_LICENSE("GPL");
291 MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>");
292 MODULE_DESCRIPTION("IBM Platform Management Interrupt driver");