xref: /openbmc/linux/arch/powerpc/sysdev/pmi.c (revision 8684014d)
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/module.h>
32 #include <linux/workqueue.h>
33 #include <linux/of_device.h>
34 #include <linux/of_platform.h>
35 
36 #include <asm/io.h>
37 #include <asm/pmi.h>
38 #include <asm/prom.h>
39 
40 struct pmi_data {
41 	struct list_head	handler;
42 	spinlock_t		handler_spinlock;
43 	spinlock_t		pmi_spinlock;
44 	struct mutex		msg_mutex;
45 	pmi_message_t		msg;
46 	struct completion	*completion;
47 	struct platform_device	*dev;
48 	int			irq;
49 	u8 __iomem		*pmi_reg;
50 	struct work_struct	work;
51 };
52 
53 static struct pmi_data *data;
54 
55 static irqreturn_t pmi_irq_handler(int irq, void *dev_id)
56 {
57 	u8 type;
58 	int rc;
59 
60 	spin_lock(&data->pmi_spinlock);
61 
62 	type = ioread8(data->pmi_reg + PMI_READ_TYPE);
63 	pr_debug("pmi: got message of type %d\n", type);
64 
65 	if (type & PMI_ACK && !data->completion) {
66 		printk(KERN_WARNING "pmi: got unexpected ACK message.\n");
67 		rc = -EIO;
68 		goto unlock;
69 	}
70 
71 	if (data->completion && !(type & PMI_ACK)) {
72 		printk(KERN_WARNING "pmi: expected ACK, but got %d\n", type);
73 		rc = -EIO;
74 		goto unlock;
75 	}
76 
77 	data->msg.type = type;
78 	data->msg.data0 = ioread8(data->pmi_reg + PMI_READ_DATA0);
79 	data->msg.data1 = ioread8(data->pmi_reg + PMI_READ_DATA1);
80 	data->msg.data2 = ioread8(data->pmi_reg + PMI_READ_DATA2);
81 	rc = 0;
82 unlock:
83 	spin_unlock(&data->pmi_spinlock);
84 
85 	if (rc == -EIO) {
86 		rc = IRQ_HANDLED;
87 		goto out;
88 	}
89 
90 	if (data->msg.type & PMI_ACK) {
91 		complete(data->completion);
92 		rc = IRQ_HANDLED;
93 		goto out;
94 	}
95 
96 	schedule_work(&data->work);
97 
98 	rc = IRQ_HANDLED;
99 out:
100 	return rc;
101 }
102 
103 
104 static const struct of_device_id pmi_match[] = {
105 	{ .type = "ibm,pmi", .name = "ibm,pmi" },
106 	{ .type = "ibm,pmi" },
107 	{},
108 };
109 
110 MODULE_DEVICE_TABLE(of, pmi_match);
111 
112 static void pmi_notify_handlers(struct work_struct *work)
113 {
114 	struct pmi_handler *handler;
115 
116 	spin_lock(&data->handler_spinlock);
117 	list_for_each_entry(handler, &data->handler, node) {
118 		pr_debug("pmi: notifying handler %p\n", handler);
119 		if (handler->type == data->msg.type)
120 			handler->handle_pmi_message(data->msg);
121 	}
122 	spin_unlock(&data->handler_spinlock);
123 }
124 
125 static int pmi_of_probe(struct platform_device *dev)
126 {
127 	struct device_node *np = dev->dev.of_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 platform_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 platform_driver pmi_of_platform_driver = {
209 	.probe		= pmi_of_probe,
210 	.remove		= pmi_of_remove,
211 	.driver = {
212 		.name = "pmi",
213 		.of_match_table = pmi_match,
214 	},
215 };
216 module_platform_driver(pmi_of_platform_driver);
217 
218 int pmi_send_message(pmi_message_t msg)
219 {
220 	unsigned long flags;
221 	DECLARE_COMPLETION_ONSTACK(completion);
222 
223 	if (!data)
224 		return -ENODEV;
225 
226 	mutex_lock(&data->msg_mutex);
227 
228 	data->msg = msg;
229 	pr_debug("pmi_send_message: msg is %08x\n", *(u32*)&msg);
230 
231 	data->completion = &completion;
232 
233 	spin_lock_irqsave(&data->pmi_spinlock, flags);
234 	iowrite8(msg.data0, data->pmi_reg + PMI_WRITE_DATA0);
235 	iowrite8(msg.data1, data->pmi_reg + PMI_WRITE_DATA1);
236 	iowrite8(msg.data2, data->pmi_reg + PMI_WRITE_DATA2);
237 	iowrite8(msg.type, data->pmi_reg + PMI_WRITE_TYPE);
238 	spin_unlock_irqrestore(&data->pmi_spinlock, flags);
239 
240 	pr_debug("pmi_send_message: wait for completion\n");
241 
242 	wait_for_completion_interruptible_timeout(data->completion,
243 						  PMI_TIMEOUT);
244 
245 	data->completion = NULL;
246 
247 	mutex_unlock(&data->msg_mutex);
248 
249 	return 0;
250 }
251 EXPORT_SYMBOL_GPL(pmi_send_message);
252 
253 int pmi_register_handler(struct pmi_handler *handler)
254 {
255 	if (!data)
256 		return -ENODEV;
257 
258 	spin_lock(&data->handler_spinlock);
259 	list_add_tail(&handler->node, &data->handler);
260 	spin_unlock(&data->handler_spinlock);
261 
262 	return 0;
263 }
264 EXPORT_SYMBOL_GPL(pmi_register_handler);
265 
266 void pmi_unregister_handler(struct pmi_handler *handler)
267 {
268 	if (!data)
269 		return;
270 
271 	pr_debug("pmi: unregistering handler %p\n", handler);
272 
273 	spin_lock(&data->handler_spinlock);
274 	list_del(&handler->node);
275 	spin_unlock(&data->handler_spinlock);
276 }
277 EXPORT_SYMBOL_GPL(pmi_unregister_handler);
278 
279 MODULE_LICENSE("GPL");
280 MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>");
281 MODULE_DESCRIPTION("IBM Platform Management Interrupt driver");
282