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/workqueue.h>
  32 #include <linux/of_device.h>
  33 #include <linux/of_platform.h>
  34
  35 #include <asm/io.h>
  36 #include <asm/pmi.h>
  37 #include <asm/prom.h>
  38
  39 struct pmi_data {
  40         struct list_head        handler;
  41         spinlock_t              handler_spinlock;
  42         spinlock_t              pmi_spinlock;
  43         struct mutex            msg_mutex;
  44         pmi_message_t           msg;
  45         struct completion       *completion;
  46         struct platform_device  *dev;
  47         int                     irq;
  48         u8 __iomem              *pmi_reg;
  49         struct work_struct      work;
  50 };
  51
  52 static struct pmi_data *data;
  53
  54 static irqreturn_t pmi_irq_handler(int irq, void *dev_id)
  55 {
  56         u8 type;
  57         int rc;
  58
  59         spin_lock(&data->pmi_spinlock);
  60
  61         type = ioread8(data->pmi_reg + PMI_READ_TYPE);
  62         pr_debug("pmi: got message of type %d\n", type);
  63
  64         if (type & PMI_ACK && !data->completion) {
  65                 printk(KERN_WARNING "pmi: got unexpected ACK message.\n");
  66                 rc = -EIO;
  67                 goto unlock;
  68         }
  69
  70         if (data->completion && !(type & PMI_ACK)) {
  71                 printk(KERN_WARNING "pmi: expected ACK, but got %d\n", type);
  72                 rc = -EIO;
  73                 goto unlock;
  74         }
  75
  76         data->msg.type = type;
  77         data->msg.data0 = ioread8(data->pmi_reg + PMI_READ_DATA0);
  78         data->msg.data1 = ioread8(data->pmi_reg + PMI_READ_DATA1);
  79         data->msg.data2 = ioread8(data->pmi_reg + PMI_READ_DATA2);
  80         rc = 0;
  81 unlock:
  82         spin_unlock(&data->pmi_spinlock);
  83
  84         if (rc == -EIO) {
  85                 rc = IRQ_HANDLED;
  86                 goto out;
  87         }
  88
  89         if (data->msg.type & PMI_ACK) {
  90                 complete(data->completion);
  91                 rc = IRQ_HANDLED;
  92                 goto out;
  93         }
  94
  95         schedule_work(&data->work);
  96
  97         rc = IRQ_HANDLED;
  98 out:
  99         return rc;
 100 }
 101
 102
 103 static struct of_device_id pmi_match[] = {
 104         { .type = "ibm,pmi", .name = "ibm,pmi" },
 105         { .type = "ibm,pmi" },
 106         {},
 107 };
 108
 109 MODULE_DEVICE_TABLE(of, pmi_match);
 110
 111 static void pmi_notify_handlers(struct work_struct *work)
 112 {
 113         struct pmi_handler *handler;
 114
 115         spin_lock(&data->handler_spinlock);
 116         list_for_each_entry(handler, &data->handler, node) {
 117                 pr_debug("pmi: notifying handler %p\n", handler);
 118                 if (handler->type == data->msg.type)
 119                         handler->handle_pmi_message(data->msg);
 120         }
 121         spin_unlock(&data->handler_spinlock);
 122 }
 123
 124 static int pmi_of_probe(struct platform_device *dev)
 125 {
 126         struct device_node *np = dev->dev.of_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 platform_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 platform_driver pmi_of_platform_driver = {
 208         .probe          = pmi_of_probe,
 209         .remove         = pmi_of_remove,
 210         .driver = {
 211                 .name = "pmi",
 212                 .owner = THIS_MODULE,
 213                 .of_match_table = pmi_match,
 214         },
 215 };
 216
 217 static int __init pmi_module_init(void)
 218 {
 219         return platform_driver_register(&pmi_of_platform_driver);
 220 }
 221 module_init(pmi_module_init);
 222
 223 static void __exit pmi_module_exit(void)
 224 {
 225         platform_driver_unregister(&pmi_of_platform_driver);
 226 }
 227 module_exit(pmi_module_exit);
 228
 229 int pmi_send_message(pmi_message_t msg)
 230 {
 231         unsigned long flags;
 232         DECLARE_COMPLETION_ONSTACK(completion);
 233
 234         if (!data)
 235                 return -ENODEV;
 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         return 0;
 261 }
 262 EXPORT_SYMBOL_GPL(pmi_send_message);
 263
 264 int pmi_register_handler(struct pmi_handler *handler)
 265 {
 266         if (!data)
 267                 return -ENODEV;
 268
 269         spin_lock(&data->handler_spinlock);
 270         list_add_tail(&handler->node, &data->handler);
 271         spin_unlock(&data->handler_spinlock);
 272
 273         return 0;
 274 }
 275 EXPORT_SYMBOL_GPL(pmi_register_handler);
 276
 277 void pmi_unregister_handler(struct pmi_handler *handler)
 278 {
 279         if (!data)
 280                 return;
 281
 282         pr_debug("pmi: unregistering handler %p\n", handler);
 283
 284         spin_lock(&data->handler_spinlock);
 285         list_del(&handler->node);
 286         spin_unlock(&data->handler_spinlock);
 287 }
 288 EXPORT_SYMBOL_GPL(pmi_unregister_handler);
 289
 290 MODULE_LICENSE("GPL");
 291 MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>");
 292 MODULE_DESCRIPTION("IBM Platform Management Interrupt driver");