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Linux/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/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 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                 .owner = THIS_MODULE,
214                 .of_match_table = pmi_match,
215         },
216 };
217 module_platform_driver(pmi_of_platform_driver);
218 
219 int pmi_send_message(pmi_message_t msg)
220 {
221         unsigned long flags;
222         DECLARE_COMPLETION_ONSTACK(completion);
223 
224         if (!data)
225                 return -ENODEV;
226 
227         mutex_lock(&data->msg_mutex);
228 
229         data->msg = msg;
230         pr_debug("pmi_send_message: msg is %08x\n", *(u32*)&msg);
231 
232         data->completion = &completion;
233 
234         spin_lock_irqsave(&data->pmi_spinlock, flags);
235         iowrite8(msg.data0, data->pmi_reg + PMI_WRITE_DATA0);
236         iowrite8(msg.data1, data->pmi_reg + PMI_WRITE_DATA1);
237         iowrite8(msg.data2, data->pmi_reg + PMI_WRITE_DATA2);
238         iowrite8(msg.type, data->pmi_reg + PMI_WRITE_TYPE);
239         spin_unlock_irqrestore(&data->pmi_spinlock, flags);
240 
241         pr_debug("pmi_send_message: wait for completion\n");
242 
243         wait_for_completion_interruptible_timeout(data->completion,
244                                                   PMI_TIMEOUT);
245 
246         data->completion = NULL;
247 
248         mutex_unlock(&data->msg_mutex);
249 
250         return 0;
251 }
252 EXPORT_SYMBOL_GPL(pmi_send_message);
253 
254 int pmi_register_handler(struct pmi_handler *handler)
255 {
256         if (!data)
257                 return -ENODEV;
258 
259         spin_lock(&data->handler_spinlock);
260         list_add_tail(&handler->node, &data->handler);
261         spin_unlock(&data->handler_spinlock);
262 
263         return 0;
264 }
265 EXPORT_SYMBOL_GPL(pmi_register_handler);
266 
267 void pmi_unregister_handler(struct pmi_handler *handler)
268 {
269         if (!data)
270                 return;
271 
272         pr_debug("pmi: unregistering handler %p\n", handler);
273 
274         spin_lock(&data->handler_spinlock);
275         list_del(&handler->node);
276         spin_unlock(&data->handler_spinlock);
277 }
278 EXPORT_SYMBOL_GPL(pmi_unregister_handler);
279 
280 MODULE_LICENSE("GPL");
281 MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>");
282 MODULE_DESCRIPTION("IBM Platform Management Interrupt driver");
283 

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