--- /dev/null
+/*
+ * pmi driver
+ *
+ * (C) Copyright IBM Deutschland Entwicklung GmbH 2005
+ *
+ * PMI (Platform Management Interrupt) is a way to communicate
+ * with the BMC (Baseboard Management Controller) via interrupts.
+ * Unlike IPMI it is bidirectional and has a low latency.
+ *
+ * Author: Christian Krafft <krafft@de.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/completion.h>
+#include <linux/spinlock.h>
+#include <linux/workqueue.h>
+
+#include <asm/of_device.h>
+#include <asm/of_platform.h>
+#include <asm/io.h>
+#include <asm/pmi.h>
+
+
+struct pmi_data {
+       struct list_head        handler;
+       spinlock_t              handler_spinlock;
+       spinlock_t              pmi_spinlock;
+       struct mutex            msg_mutex;
+       pmi_message_t           msg;
+       struct completion       *completion;
+       struct of_device        *dev;
+       int                     irq;
+       u8 __iomem              *pmi_reg;
+       struct work_struct      work;
+};
+
+
+
+static void __iomem *of_iomap(struct device_node *np)
+{
+       struct resource res;
+
+       if (of_address_to_resource(np, 0, &res))
+               return NULL;
+
+       pr_debug("Resource start: 0x%lx\n", res.start);
+       pr_debug("Resource end: 0x%lx\n", res.end);
+
+       return ioremap(res.start, 1 + res.end - res.start);
+}
+
+
+static int pmi_irq_handler(int irq, void *dev_id)
+{
+       struct pmi_data *data;
+       u8 type;
+       int rc;
+
+       data = dev_id;
+
+       spin_lock(&data->pmi_spinlock);
+
+       type = ioread8(data->pmi_reg + PMI_READ_TYPE);
+       pr_debug("pmi: got message of type %d\n", type);
+
+       if (type & PMI_ACK && !data->completion) {
+               printk(KERN_WARNING "pmi: got unexpected ACK message.\n");
+               rc = -EIO;
+               goto unlock;
+       }
+
+       if (data->completion && !(type & PMI_ACK)) {
+               printk(KERN_WARNING "pmi: expected ACK, but got %d\n", type);
+               rc = -EIO;
+               goto unlock;
+       }
+
+       data->msg.type = type;
+       data->msg.data0 = ioread8(data->pmi_reg + PMI_READ_DATA0);
+       data->msg.data1 = ioread8(data->pmi_reg + PMI_READ_DATA1);
+       data->msg.data2 = ioread8(data->pmi_reg + PMI_READ_DATA2);
+       rc = 0;
+unlock:
+       spin_unlock(&data->pmi_spinlock);
+
+       if (rc == -EIO) {
+               rc = IRQ_HANDLED;
+               goto out;
+       }
+
+       if (data->msg.type & PMI_ACK) {
+               complete(data->completion);
+               rc = IRQ_HANDLED;
+               goto out;
+       }
+
+       schedule_work(&data->work);
+
+       rc = IRQ_HANDLED;
+out:
+       return rc;
+}
+
+
+static struct of_device_id pmi_match[] = {
+       { .type = "ibm,pmi", .name = "ibm,pmi" },
+       {},
+};
+
+MODULE_DEVICE_TABLE(of, pmi_match);
+
+static void pmi_notify_handlers(struct work_struct *work)
+{
+       struct pmi_data *data;
+       struct pmi_handler *handler;
+
+       data = container_of(work, struct pmi_data, work);
+
+       spin_lock(&data->handler_spinlock);
+       list_for_each_entry(handler, &data->handler, node) {
+               pr_debug(KERN_INFO "pmi: notifying handler %p\n", handler);
+               if (handler->type == data->msg.type)
+                       handler->handle_pmi_message(data->dev, data->msg);
+       }
+       spin_unlock(&data->handler_spinlock);
+}
+
+static int pmi_of_probe(struct of_device *dev,
+                       const struct of_device_id *match)
+{
+       struct device_node *np = dev->node;
+       struct pmi_data *data;
+       int rc;
+
+       data = kzalloc(sizeof(struct pmi_data), GFP_KERNEL);
+       if (!data) {
+               printk(KERN_ERR "pmi: could not allocate memory.\n");
+               rc = -ENOMEM;
+               goto out;
+       }
+
+       data->pmi_reg = of_iomap(np);
+       if (!data->pmi_reg) {
+               printk(KERN_ERR "pmi: invalid register address.\n");
+               rc = -EFAULT;
+               goto error_cleanup_data;
+       }
+
+       INIT_LIST_HEAD(&data->handler);
+
+       mutex_init(&data->msg_mutex);
+       spin_lock_init(&data->pmi_spinlock);
+       spin_lock_init(&data->handler_spinlock);
+
+       INIT_WORK(&data->work, pmi_notify_handlers);
+
+       dev->dev.driver_data = data;
+       data->dev = dev;
+
+       data->irq = irq_of_parse_and_map(np, 0);
+       if (data->irq == NO_IRQ) {
+               printk(KERN_ERR "pmi: invalid interrupt.\n");
+               rc = -EFAULT;
+               goto error_cleanup_iomap;
+       }
+
+       rc = request_irq(data->irq, pmi_irq_handler, 0, "pmi", data);
+       if (rc) {
+               printk(KERN_ERR "pmi: can't request IRQ %d: returned %d\n",
+                               data->irq, rc);
+               goto error_cleanup_iomap;
+       }
+
+       printk(KERN_INFO "pmi: found pmi device at addr %p.\n", data->pmi_reg);
+
+       goto out;
+
+error_cleanup_iomap:
+       iounmap(data->pmi_reg);
+
+error_cleanup_data:
+       kfree(data);
+
+out:
+       return rc;
+}
+
+static int pmi_of_remove(struct of_device *dev)
+{
+       struct pmi_data *data;
+       struct pmi_handler *handler, *tmp;
+
+       data = dev->dev.driver_data;
+
+       free_irq(data->irq, data);
+       iounmap(data->pmi_reg);
+
+       spin_lock(&data->handler_spinlock);
+
+       list_for_each_entry_safe(handler, tmp, &data->handler, node)
+               list_del(&handler->node);
+
+       spin_unlock(&data->handler_spinlock);
+
+       kfree(dev->dev.driver_data);
+
+       return 0;
+}
+
+static struct of_platform_driver pmi_of_platform_driver = {
+       .name           = "pmi",
+       .match_table    = pmi_match,
+       .probe          = pmi_of_probe,
+       .remove         = pmi_of_remove
+};
+
+static int __init pmi_module_init(void)
+{
+       return of_register_platform_driver(&pmi_of_platform_driver);
+}
+module_init(pmi_module_init);
+
+static void __exit pmi_module_exit(void)
+{
+       of_unregister_platform_driver(&pmi_of_platform_driver);
+}
+module_exit(pmi_module_exit);
+
+void pmi_send_message(struct of_device *device, pmi_message_t msg)
+{
+       struct pmi_data *data;
+       unsigned long flags;
+       DECLARE_COMPLETION_ONSTACK(completion);
+
+       data = device->dev.driver_data;
+
+       mutex_lock(&data->msg_mutex);
+
+       data->msg = msg;
+       pr_debug("pmi_send_message: msg is %08x\n", *(u32*)&msg);
+
+       data->completion = &completion;
+
+       spin_lock_irqsave(&data->pmi_spinlock, flags);
+       iowrite8(msg.data0, data->pmi_reg + PMI_WRITE_DATA0);
+       iowrite8(msg.data1, data->pmi_reg + PMI_WRITE_DATA1);
+       iowrite8(msg.data2, data->pmi_reg + PMI_WRITE_DATA2);
+       iowrite8(msg.type, data->pmi_reg + PMI_WRITE_TYPE);
+       spin_unlock_irqrestore(&data->pmi_spinlock, flags);
+
+       pr_debug("pmi_send_message: wait for completion\n");
+
+       wait_for_completion_interruptible_timeout(data->completion,
+                                                 PMI_TIMEOUT);
+
+       data->completion = NULL;
+
+       mutex_unlock(&data->msg_mutex);
+}
+EXPORT_SYMBOL_GPL(pmi_send_message);
+
+void pmi_register_handler(struct of_device *device,
+                         struct pmi_handler *handler)
+{
+       struct pmi_data *data;
+       data = device->dev.driver_data;
+
+       spin_lock(&data->handler_spinlock);
+       list_add_tail(&handler->node, &data->handler);
+       spin_unlock(&data->handler_spinlock);
+}
+EXPORT_SYMBOL_GPL(pmi_register_handler);
+
+void pmi_unregister_handler(struct of_device *device,
+                           struct pmi_handler *handler)
+{
+       struct pmi_data *data;
+
+       pr_debug("pmi: unregistering handler %p\n", handler);
+
+       data = device->dev.driver_data;
+
+       spin_lock(&data->handler_spinlock);
+       list_del(&handler->node);
+       spin_unlock(&data->handler_spinlock);
+}
+EXPORT_SYMBOL_GPL(pmi_unregister_handler);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>");
+MODULE_DESCRIPTION("IBM Platform Management Interrupt driver");
 
--- /dev/null
+#ifndef _POWERPC_PMI_H
+#define _POWERPC_PMI_H
+
+/*
+ * Definitions for talking with PMI device on PowerPC
+ *
+ * PMI (Platform Management Interrupt) is a way to communicate
+ * with the BMC (Baseboard Management Controller) via interrupts.
+ * Unlike IPMI it is bidirectional and has a low latency.
+ *
+ * (C) Copyright IBM Deutschland Entwicklung GmbH 2005
+ *
+ * Author: Christian Krafft <krafft@de.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#ifdef __KERNEL__
+
+#include <asm/of_device.h>
+
+#define PMI_TYPE_FREQ_CHANGE   0x01
+#define PMI_READ_TYPE          0
+#define PMI_READ_DATA0         1
+#define PMI_READ_DATA1         2
+#define PMI_READ_DATA2         3
+#define PMI_WRITE_TYPE         4
+#define PMI_WRITE_DATA0                5
+#define PMI_WRITE_DATA1                6
+#define PMI_WRITE_DATA2                7
+
+#define PMI_ACK                        0x80
+
+#define PMI_TIMEOUT            100
+
+typedef struct {
+       u8      type;
+       u8      data0;
+       u8      data1;
+       u8      data2;
+} pmi_message_t;
+
+struct pmi_handler {
+       struct list_head node;
+       u8 type;
+       void (*handle_pmi_message) (struct of_device *, pmi_message_t);
+};
+
+void pmi_register_handler(struct of_device *, struct pmi_handler *);
+void pmi_unregister_handler(struct of_device *, struct pmi_handler *);
+
+void pmi_send_message(struct of_device *, pmi_message_t);
+
+#endif /* __KERNEL__ */
+#endif /* _POWERPC_PMI_H */