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
  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
  53 static void __iomem *of_iomap(struct device_node *np)
  54 {
  55         struct resource res;
  56
  57         if (of_address_to_resource(np, 0, &res))
  58                 return NULL;
  59
  60         pr_debug("Resource start: 0x%lx\n", res.start);
  61         pr_debug("Resource end: 0x%lx\n", res.end);
  62
  63         return ioremap(res.start, 1 + res.end - res.start);
  64 }
  65
  66
  67 static int pmi_irq_handler(int irq, void *dev_id)
  68 {
  69         struct pmi_data *data;
  70         u8 type;
  71         int rc;
  72
  73         data = dev_id;
  74
  75         spin_lock(&data->pmi_spinlock);
  76
  77         type = ioread8(data->pmi_reg + PMI_READ_TYPE);
  78         pr_debug("pmi: got message of type %d\n", type);
  79
  80         if (type & PMI_ACK && !data->completion) {
  81                 printk(KERN_WARNING "pmi: got unexpected ACK message.\n");
  82                 rc = -EIO;
  83                 goto unlock;
  84         }
  85
  86         if (data->completion && !(type & PMI_ACK)) {
  87                 printk(KERN_WARNING "pmi: expected ACK, but got %d\n", type);
  88                 rc = -EIO;
  89                 goto unlock;
  90         }
  91
  92         data->msg.type = type;
  93         data->msg.data0 = ioread8(data->pmi_reg + PMI_READ_DATA0);
  94         data->msg.data1 = ioread8(data->pmi_reg + PMI_READ_DATA1);
  95         data->msg.data2 = ioread8(data->pmi_reg + PMI_READ_DATA2);
  96         rc = 0;
  97 unlock:
  98         spin_unlock(&data->pmi_spinlock);
  99
 100         if (rc == -EIO) {
 101                 rc = IRQ_HANDLED;
 102                 goto out;
 103         }
 104
 105         if (data->msg.type & PMI_ACK) {
 106                 complete(data->completion);
 107                 rc = IRQ_HANDLED;
 108                 goto out;
 109         }
 110
 111         schedule_work(&data->work);
 112
 113         rc = IRQ_HANDLED;
 114 out:
 115         return rc;
 116 }
 117
 118
 119 static struct of_device_id pmi_match[] = {
 120         { .type = "ibm,pmi", .name = "ibm,pmi" },
 121         {},
 122 };
 123
 124 MODULE_DEVICE_TABLE(of, pmi_match);
 125
 126 static void pmi_notify_handlers(struct work_struct *work)
 127 {
 128         struct pmi_data *data;
 129         struct pmi_handler *handler;
 130
 131         data = container_of(work, struct pmi_data, work);
 132
 133         spin_lock(&data->handler_spinlock);
 134         list_for_each_entry(handler, &data->handler, node) {
 135                 pr_debug(KERN_INFO "pmi: notifying handler %p\n", handler);
 136                 if (handler->type == data->msg.type)
 137                         handler->handle_pmi_message(data->dev, data->msg);
 138         }
 139         spin_unlock(&data->handler_spinlock);
 140 }
 141
 142 static int pmi_of_probe(struct of_device *dev,
 143                         const struct of_device_id *match)
 144 {
 145         struct device_node *np = dev->node;
 146         struct pmi_data *data;
 147         int rc;
 148
 149         data = kzalloc(sizeof(struct pmi_data), GFP_KERNEL);
 150         if (!data) {
 151                 printk(KERN_ERR "pmi: could not allocate memory.\n");
 152                 rc = -ENOMEM;
 153                 goto out;
 154         }
 155
 156         data->pmi_reg = of_iomap(np);
 157         if (!data->pmi_reg) {
 158                 printk(KERN_ERR "pmi: invalid register address.\n");
 159                 rc = -EFAULT;
 160                 goto error_cleanup_data;
 161         }
 162
 163         INIT_LIST_HEAD(&data->handler);
 164
 165         mutex_init(&data->msg_mutex);
 166         spin_lock_init(&data->pmi_spinlock);
 167         spin_lock_init(&data->handler_spinlock);
 168
 169         INIT_WORK(&data->work, pmi_notify_handlers);
 170
 171         dev->dev.driver_data = data;
 172         data->dev = dev;
 173
 174         data->irq = irq_of_parse_and_map(np, 0);
 175         if (data->irq == NO_IRQ) {
 176                 printk(KERN_ERR "pmi: invalid interrupt.\n");
 177                 rc = -EFAULT;
 178                 goto error_cleanup_iomap;
 179         }
 180
 181         rc = request_irq(data->irq, pmi_irq_handler, 0, "pmi", data);
 182         if (rc) {
 183                 printk(KERN_ERR "pmi: can't request IRQ %d: returned %d\n",
 184                                 data->irq, rc);
 185                 goto error_cleanup_iomap;
 186         }
 187
 188         printk(KERN_INFO "pmi: found pmi device at addr %p.\n", data->pmi_reg);
 189
 190         goto out;
 191
 192 error_cleanup_iomap:
 193         iounmap(data->pmi_reg);
 194
 195 error_cleanup_data:
 196         kfree(data);
 197
 198 out:
 199         return rc;
 200 }
 201
 202 static int pmi_of_remove(struct of_device *dev)
 203 {
 204         struct pmi_data *data;
 205         struct pmi_handler *handler, *tmp;
 206
 207         data = dev->dev.driver_data;
 208
 209         free_irq(data->irq, data);
 210         iounmap(data->pmi_reg);
 211
 212         spin_lock(&data->handler_spinlock);
 213
 214         list_for_each_entry_safe(handler, tmp, &data->handler, node)
 215                 list_del(&handler->node);
 216
 217         spin_unlock(&data->handler_spinlock);
 218
 219         kfree(dev->dev.driver_data);
 220
 221         return 0;
 222 }
 223
 224 static struct of_platform_driver pmi_of_platform_driver = {
 225         .name           = "pmi",
 226         .match_table    = pmi_match,
 227         .probe          = pmi_of_probe,
 228         .remove         = pmi_of_remove
 229 };
 230
 231 static int __init pmi_module_init(void)
 232 {
 233         return of_register_platform_driver(&pmi_of_platform_driver);
 234 }
 235 module_init(pmi_module_init);
 236
 237 static void __exit pmi_module_exit(void)
 238 {
 239         of_unregister_platform_driver(&pmi_of_platform_driver);
 240 }
 241 module_exit(pmi_module_exit);
 242
 243 void pmi_send_message(struct of_device *device, pmi_message_t msg)
 244 {
 245         struct pmi_data *data;
 246         unsigned long flags;
 247         DECLARE_COMPLETION_ONSTACK(completion);
 248
 249         data = device->dev.driver_data;
 250
 251         mutex_lock(&data->msg_mutex);
 252
 253         data->msg = msg;
 254         pr_debug("pmi_send_message: msg is %08x\n", *(u32*)&msg);
 255
 256         data->completion = &completion;
 257
 258         spin_lock_irqsave(&data->pmi_spinlock, flags);
 259         iowrite8(msg.data0, data->pmi_reg + PMI_WRITE_DATA0);
 260         iowrite8(msg.data1, data->pmi_reg + PMI_WRITE_DATA1);
 261         iowrite8(msg.data2, data->pmi_reg + PMI_WRITE_DATA2);
 262         iowrite8(msg.type, data->pmi_reg + PMI_WRITE_TYPE);
 263         spin_unlock_irqrestore(&data->pmi_spinlock, flags);
 264
 265         pr_debug("pmi_send_message: wait for completion\n");
 266
 267         wait_for_completion_interruptible_timeout(data->completion,
 268                                                   PMI_TIMEOUT);
 269
 270         data->completion = NULL;
 271
 272         mutex_unlock(&data->msg_mutex);
 273 }
 274 EXPORT_SYMBOL_GPL(pmi_send_message);
 275
 276 void pmi_register_handler(struct of_device *device,
 277                           struct pmi_handler *handler)
 278 {
 279         struct pmi_data *data;
 280         data = device->dev.driver_data;
 281
 282         spin_lock(&data->handler_spinlock);
 283         list_add_tail(&handler->node, &data->handler);
 284         spin_unlock(&data->handler_spinlock);
 285 }
 286 EXPORT_SYMBOL_GPL(pmi_register_handler);
 287
 288 void pmi_unregister_handler(struct of_device *device,
 289                             struct pmi_handler *handler)
 290 {
 291         struct pmi_data *data;
 292
 293         pr_debug("pmi: unregistering handler %p\n", handler);
 294
 295         data = device->dev.driver_data;
 296
 297         spin_lock(&data->handler_spinlock);
 298         list_del(&handler->node);
 299         spin_unlock(&data->handler_spinlock);
 300 }
 301 EXPORT_SYMBOL_GPL(pmi_unregister_handler);
 302
 303 MODULE_LICENSE("GPL");
 304 MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>");
 305 MODULE_DESCRIPTION("IBM Platform Management Interrupt driver");