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