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/completion.h>
  29 #include <linux/spinlock.h>
  30 #include <linux/workqueue.h>
  31
  32 #include <asm/of_device.h>
  33 #include <asm/of_platform.h>
  34 #include <asm/io.h>
  35 #include <asm/pmi.h>
  36 #include <asm/prom.h>
  37
  38 struct pmi_data {
  39         struct list_head        handler;
  40         spinlock_t              handler_spinlock;
  41         spinlock_t              pmi_spinlock;
  42         struct mutex            msg_mutex;
  43         pmi_message_t           msg;
  44         struct completion       *completion;
  45         struct of_device        *dev;
  46         int                     irq;
  47         u8 __iomem              *pmi_reg;
  48         struct work_struct      work;
  49 };
  50
  51
  52 static int pmi_irq_handler(int irq, void *dev_id)
  53 {
  54         struct pmi_data *data;
  55         u8 type;
  56         int rc;
  57
  58         data = dev_id;
  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_data *data;
 115         struct pmi_handler *handler;
 116
 117         data = container_of(work, struct pmi_data, work);
 118
 119         spin_lock(&data->handler_spinlock);
 120         list_for_each_entry(handler, &data->handler, node) {
 121                 pr_debug(KERN_INFO "pmi: notifying handler %p\n", handler);
 122                 if (handler->type == data->msg.type)
 123                         handler->handle_pmi_message(data->dev, data->msg);
 124         }
 125         spin_unlock(&data->handler_spinlock);
 126 }
 127
 128 static int pmi_of_probe(struct of_device *dev,
 129                         const struct of_device_id *match)
 130 {
 131         struct device_node *np = dev->node;
 132         struct pmi_data *data;
 133         int rc;
 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         dev->dev.driver_data = data;
 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", data);
 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_data *data;
 191         struct pmi_handler *handler, *tmp;
 192
 193         data = dev->dev.driver_data;
 194
 195         free_irq(data->irq, data);
 196         iounmap(data->pmi_reg);
 197
 198         spin_lock(&data->handler_spinlock);
 199
 200         list_for_each_entry_safe(handler, tmp, &data->handler, node)
 201                 list_del(&handler->node);
 202
 203         spin_unlock(&data->handler_spinlock);
 204
 205         kfree(dev->dev.driver_data);
 206
 207         return 0;
 208 }
 209
 210 static struct of_platform_driver pmi_of_platform_driver = {
 211         .name           = "pmi",
 212         .match_table    = pmi_match,
 213         .probe          = pmi_of_probe,
 214         .remove         = pmi_of_remove
 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 void pmi_send_message(struct of_device *device, pmi_message_t msg)
 230 {
 231         struct pmi_data *data;
 232         unsigned long flags;
 233         DECLARE_COMPLETION_ONSTACK(completion);
 234
 235         data = device->dev.driver_data;
 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 EXPORT_SYMBOL_GPL(pmi_send_message);
 261
 262 void pmi_register_handler(struct of_device *device,
 263                           struct pmi_handler *handler)
 264 {
 265         struct pmi_data *data;
 266         data = device->dev.driver_data;
 267
 268         if (!data)
 269                 return;
 270
 271         spin_lock(&data->handler_spinlock);
 272         list_add_tail(&handler->node, &data->handler);
 273         spin_unlock(&data->handler_spinlock);
 274 }
 275 EXPORT_SYMBOL_GPL(pmi_register_handler);
 276
 277 void pmi_unregister_handler(struct of_device *device,
 278                             struct pmi_handler *handler)
 279 {
 280         struct pmi_data *data;
 281         data = device->dev.driver_data;
 282
 283         if (!data)
 284                 return;
 285
 286         pr_debug("pmi: unregistering handler %p\n", handler);
 287
 288         spin_lock(&data->handler_spinlock);
 289         list_del(&handler->node);
 290         spin_unlock(&data->handler_spinlock);
 291 }
 292 EXPORT_SYMBOL_GPL(pmi_unregister_handler);
 293
 294 MODULE_LICENSE("GPL");
 295 MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>");
 296 MODULE_DESCRIPTION("IBM Platform Management Interrupt driver");