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 platform_device *dev;
47 int irq;
48 u8 __iomem *pmi_reg;
49 struct work_struct work;
50 };
51
52 static struct pmi_data *data;
53
pmi_irq_handler(int irq,void * dev_id)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
pmi_notify_handlers(struct work_struct * work)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("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
pmi_of_probe(struct platform_device * dev)124 static int pmi_of_probe(struct platform_device *dev)
125 {
126 struct device_node *np = dev->dev.of_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
pmi_of_remove(struct platform_device * dev)187 static int pmi_of_remove(struct platform_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 platform_driver pmi_of_platform_driver = {
208 .probe = pmi_of_probe,
209 .remove = pmi_of_remove,
210 .driver = {
211 .name = "pmi",
212 .owner = THIS_MODULE,
213 .of_match_table = pmi_match,
214 },
215 };
216
pmi_module_init(void)217 static int __init pmi_module_init(void)
218 {
219 return platform_driver_register(&pmi_of_platform_driver);
220 }
221 module_init(pmi_module_init);
222
pmi_module_exit(void)223 static void __exit pmi_module_exit(void)
224 {
225 platform_driver_unregister(&pmi_of_platform_driver);
226 }
227 module_exit(pmi_module_exit);
228
pmi_send_message(pmi_message_t msg)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
pmi_register_handler(struct pmi_handler * handler)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
pmi_unregister_handler(struct pmi_handler * handler)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");
293