aboutsummaryrefslogtreecommitdiff
path: root/arch/powerpc/sysdev/pmi.c
blob: 24a0bb955b184bba92c6d0d9efda52ac568bee74 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
/*
 * pmi driver
 *
 * (C) Copyright IBM Deutschland Entwicklung GmbH 2005
 *
 * PMI (Platform Management Interrupt) is a way to communicate
 * with the BMC (Baseboard Management Controller) via interrupts.
 * Unlike IPMI it is bidirectional and has a low latency.
 *
 * Author: Christian Krafft <krafft@de.ibm.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/interrupt.h>
#include <linux/slab.h>
#include <linux/completion.h>
#include <linux/spinlock.h>
#include <linux/workqueue.h>
#include <linux/of_device.h>
#include <linux/of_platform.h>

#include <asm/io.h>
#include <asm/pmi.h>
#include <asm/prom.h>

struct pmi_data {
	struct list_head	handler;
	spinlock_t		handler_spinlock;
	spinlock_t		pmi_spinlock;
	struct mutex		msg_mutex;
	pmi_message_t		msg;
	struct completion	*completion;
	struct platform_device	*dev;
	int			irq;
	u8 __iomem		*pmi_reg;
	struct work_struct	work;
};

static struct pmi_data *data;

static irqreturn_t pmi_irq_handler(int irq, void *dev_id)
{
	u8 type;
	int rc;

	spin_lock(&data->pmi_spinlock);

	type = ioread8(data->pmi_reg + PMI_READ_TYPE);
	pr_debug("pmi: got message of type %d\n", type);

	if (type & PMI_ACK && !data->completion) {
		printk(KERN_WARNING "pmi: got unexpected ACK message.\n");
		rc = -EIO;
		goto unlock;
	}

	if (data->completion && !(type & PMI_ACK)) {
		printk(KERN_WARNING "pmi: expected ACK, but got %d\n", type);
		rc = -EIO;
		goto unlock;
	}

	data->msg.type = type;
	data->msg.data0 = ioread8(data->pmi_reg + PMI_READ_DATA0);
	data->msg.data1 = ioread8(data->pmi_reg + PMI_READ_DATA1);
	data->msg.data2 = ioread8(data->pmi_reg + PMI_READ_DATA2);
	rc = 0;
unlock:
	spin_unlock(&data->pmi_spinlock);

	if (rc == -EIO) {
		rc = IRQ_HANDLED;
		goto out;
	}

	if (data->msg.type & PMI_ACK) {
		complete(data->completion);
		rc = IRQ_HANDLED;
		goto out;
	}

	schedule_work(&data->work);

	rc = IRQ_HANDLED;
out:
	return rc;
}


static struct of_device_id pmi_match[] = {
	{ .type = "ibm,pmi", .name = "ibm,pmi" },
	{ .type = "ibm,pmi" },
	{},
};

MODULE_DEVICE_TABLE(of, pmi_match);

static void pmi_notify_handlers(struct work_struct *work)
{
	struct pmi_handler *handler;

	spin_lock(&data->handler_spinlock);
	list_for_each_entry(handler, &data->handler, node) {
		pr_debug(KERN_INFO "pmi: notifying handler %p\n", handler);
		if (handler->type == data->msg.type)
			handler->handle_pmi_message(data->msg);
	}
	spin_unlock(&data->handler_spinlock);
}

static int pmi_of_probe(struct platform_device *dev,
			const struct of_device_id *match)
{
	struct device_node *np = dev->dev.of_node;
	int rc;

	if (data) {
		printk(KERN_ERR "pmi: driver has already been initialized.\n");
		rc = -EBUSY;
		goto out;
	}

	data = kzalloc(sizeof(struct pmi_data), GFP_KERNEL);
	if (!data) {
		printk(KERN_ERR "pmi: could not allocate memory.\n");
		rc = -ENOMEM;
		goto out;
	}

	data->pmi_reg = of_iomap(np, 0);
	if (!data->pmi_reg) {
		printk(KERN_ERR "pmi: invalid register address.\n");
		rc = -EFAULT;
		goto error_cleanup_data;
	}

	INIT_LIST_HEAD(&data->handler);

	mutex_init(&data->msg_mutex);
	spin_lock_init(&data->pmi_spinlock);
	spin_lock_init(&data->handler_spinlock);

	INIT_WORK(&data->work, pmi_notify_handlers);

	data->dev = dev;

	data->irq = irq_of_parse_and_map(np, 0);
	if (data->irq == NO_IRQ) {
		printk(KERN_ERR "pmi: invalid interrupt.\n");
		rc = -EFAULT;
		goto error_cleanup_iomap;
	}

	rc = request_irq(data->irq, pmi_irq_handler, 0, "pmi", NULL);
	if (rc) {
		printk(KERN_ERR "pmi: can't request IRQ %d: returned %d\n",
				data->irq, rc);
		goto error_cleanup_iomap;
	}

	printk(KERN_INFO "pmi: found pmi device at addr %p.\n", data->pmi_reg);

	goto out;

error_cleanup_iomap:
	iounmap(data->pmi_reg);

error_cleanup_data:
	kfree(data);

out:
	return rc;
}

static int pmi_of_remove(struct platform_device *dev)
{
	struct pmi_handler *handler, *tmp;

	free_irq(data->irq, NULL);
	iounmap(data->pmi_reg);

	spin_lock(&data->handler_spinlock);

	list_for_each_entry_safe(handler, tmp, &data->handler, node)
		list_del(&handler->node);

	spin_unlock(&data->handler_spinlock);

	kfree(data);
	data = NULL;

	return 0;
}

static struct of_platform_driver pmi_of_platform_driver = {
	.probe		= pmi_of_probe,
	.remove		= pmi_of_remove,
	.driver = {
		.name = "pmi",
		.owner = THIS_MODULE,
		.of_match_table = pmi_match,
	},
};

static int __init pmi_module_init(void)
{
	return of_register_platform_driver(&pmi_of_platform_driver);
}
module_init(pmi_module_init);

static void __exit pmi_module_exit(void)
{
	of_unregister_platform_driver(&pmi_of_platform_driver);
}
module_exit(pmi_module_exit);

int pmi_send_message(pmi_message_t msg)
{
	unsigned long flags;
	DECLARE_COMPLETION_ONSTACK(completion);

	if (!data)
		return -ENODEV;

	mutex_lock(&data->msg_mutex);

	data->msg = msg;
	pr_debug("pmi_send_message: msg is %08x\n", *(u32*)&msg);

	data->completion = &completion;

	spin_lock_irqsave(&data->pmi_spinlock, flags);
	iowrite8(msg.data0, data->pmi_reg + PMI_WRITE_DATA0);
	iowrite8(msg.data1, data->pmi_reg + PMI_WRITE_DATA1);
	iowrite8(msg.data2, data->pmi_reg + PMI_WRITE_DATA2);
	iowrite8(msg.type, data->pmi_reg + PMI_WRITE_TYPE);
	spin_unlock_irqrestore(&data->pmi_spinlock, flags);

	pr_debug("pmi_send_message: wait for completion\n");

	wait_for_completion_interruptible_timeout(data->completion,
						  PMI_TIMEOUT);

	data->completion = NULL;

	mutex_unlock(&data->msg_mutex);

	return 0;
}
EXPORT_SYMBOL_GPL(pmi_send_message);

int pmi_register_handler(struct pmi_handler *handler)
{
	if (!data)
		return -ENODEV;

	spin_lock(&data->handler_spinlock);
	list_add_tail(&handler->node, &data->handler);
	spin_unlock(&data->handler_spinlock);

	return 0;
}
EXPORT_SYMBOL_GPL(pmi_register_handler);

void pmi_unregister_handler(struct pmi_handler *handler)
{
	if (!data)
		return;

	pr_debug("pmi: unregistering handler %p\n", handler);

	spin_lock(&data->handler_spinlock);
	list_del(&handler->node);
	spin_unlock(&data->handler_spinlock);
}
EXPORT_SYMBOL_GPL(pmi_unregister_handler);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>");
MODULE_DESCRIPTION("IBM Platform Management Interrupt driver");