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 #include <linux/of_device.h>
  32 #include <linux/of_platform.h>
  33
  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 static struct pmi_data *data;
  52
  53 static irqreturn_t pmi_irq_handler(int irq, void *dev_id)
  54 {
  55         u8 type;
  56         int rc;
  57
  58         spin_lock(&data->pmi_spinlock);
  59
  60         type = ioread8(data->pmi_reg + PMI_READ_TYPE);
  61         pr_debug("pmi: got message of type %d\n", type);
  62
  63         if (type & PMI_ACK && !data->completion) {
  64                 printk(KERN_WARNING "pmi: got unexpected ACK message.\n");
  65                 rc = -EIO;
  66                 goto unlock;
  67         }
  68
  69         if (data->completion && !(type & PMI_ACK)) {
  70                 printk(KERN_WARNING "pmi: expected ACK, but got %d\n", type);
  71                 rc = -EIO;
  72                 goto unlock;
  73         }
  74
  75         data->msg.type = type;
  76         data->msg.data0 = ioread8(data->pmi_reg + PMI_READ_DATA0);
  77         data->msg.data1 = ioread8(data->pmi_reg + PMI_READ_DATA1);
  78         data->msg.data2 = ioread8(data->pmi_reg + PMI_READ_DATA2);
  79         rc = 0;
  80 unlock:
  81         spin_unlock(&data->pmi_spinlock);
  82
  83         if (rc == -EIO) {
  84                 rc = IRQ_HANDLED;
  85                 goto out;
  86         }
  87
  88         if (data->msg.type & PMI_ACK) {
  89                 complete(data->completion);
  90                 rc = IRQ_HANDLED;
  91                 goto out;
  92         }
  93
  94         schedule_work(&data->work);
  95
  96         rc = IRQ_HANDLED;
  97 out:
  98         return rc;
  99 }
 100
 101
 102 static struct of_device_id pmi_match[] = {
 103         { .type = "ibm,pmi", .name = "ibm,pmi" },
 104         { .type = "ibm,pmi" },
 105         {},
 106 };
 107
 108 MODULE_DEVICE_TABLE(of, pmi_match);
 109
 110 static void pmi_notify_handlers(struct work_struct *work)
 111 {
 112         struct pmi_handler *handler;
 113
 114         spin_lock(&data->handler_spinlock);
 115         list_for_each_entry(handler, &data->handler, node) {
 116                 pr_debug(KERN_INFO "pmi: notifying handler %p\n", handler);
 117                 if (handler->type == data->msg.type)
 118                         handler->handle_pmi_message(data->msg);
 119         }
 120         spin_unlock(&data->handler_spinlock);
 121 }
 122
 123 static int pmi_of_probe(struct of_device *dev,
 124                         const struct of_device_id *match)
 125 {
 126         struct device_node *np = dev->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
 187 static int pmi_of_remove(struct of_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 of_platform_driver pmi_of_platform_driver = {
 208         .match_table    = pmi_match,
 209         .probe          = pmi_of_probe,
 210         .remove         = pmi_of_remove,
 211         .driver         = {
 212                 .name   = "pmi",
 213         },
 214 };
 215
 216 static int __init pmi_module_init(void)
 217 {
 218         return of_register_platform_driver(&pmi_of_platform_driver);
 219 }
 220 module_init(pmi_module_init);
 221
 222 static void __exit pmi_module_exit(void)
 223 {
 224         of_unregister_platform_driver(&pmi_of_platform_driver);
 225 }
 226 module_exit(pmi_module_exit);
 227
 228 int pmi_send_message(pmi_message_t msg)
 229 {
 230         unsigned long flags;
 231         DECLARE_COMPLETION_ONSTACK(completion);
 232
 233         if (!data)
 234                 return -ENODEV;
 235
 236         mutex_lock(&data->msg_mutex);
 237
 238         data->msg = msg;
 239         pr_debug("pmi_send_message: msg is %08x\n", *(u32*)&msg);
 240
 241         data->completion = &completion;
 242
 243         spin_lock_irqsave(&data->pmi_spinlock, flags);
 244         iowrite8(msg.data0, data->pmi_reg + PMI_WRITE_DATA0);
 245         iowrite8(msg.data1, data->pmi_reg + PMI_WRITE_DATA1);
 246         iowrite8(msg.data2, data->pmi_reg + PMI_WRITE_DATA2);
 247         iowrite8(msg.type, data->pmi_reg + PMI_WRITE_TYPE);
 248         spin_unlock_irqrestore(&data->pmi_spinlock, flags);
 249
 250         pr_debug("pmi_send_message: wait for completion\n");
 251
 252         wait_for_completion_interruptible_timeout(data->completion,
 253                                                   PMI_TIMEOUT);
 254
 255         data->completion = NULL;
 256
 257         mutex_unlock(&data->msg_mutex);
 258
 259         return 0;
 260 }
 261 EXPORT_SYMBOL_GPL(pmi_send_message);
 262
 263 int pmi_register_handler(struct pmi_handler *handler)
 264 {
 265         if (!data)
 266                 return -ENODEV;
 267
 268         spin_lock(&data->handler_spinlock);
 269         list_add_tail(&handler->node, &data->handler);
 270         spin_unlock(&data->handler_spinlock);
 271
 272         return 0;
 273 }
 274 EXPORT_SYMBOL_GPL(pmi_register_handler);
 275
 276 void pmi_unregister_handler(struct pmi_handler *handler)
 277 {
 278         if (!data)
 279                 return;
 280
 281         pr_debug("pmi: unregistering handler %p\n", handler);
 282
 283         spin_lock(&data->handler_spinlock);
 284         list_del(&handler->node);
 285         spin_unlock(&data->handler_spinlock);
 286 }
 287 EXPORT_SYMBOL_GPL(pmi_unregister_handler);
 288
 289 MODULE_LICENSE("GPL");
 290 MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>");
 291 MODULE_DESCRIPTION("IBM Platform Management Interrupt driver");