[POWERPC] add check for initialized driver data to pmi driver

[firewire-audio.git] / arch / powerpc / sysdev / pmi.c

/*
 * 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;

        if (!data)
                return;

        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;
        data = device->dev.driver_data;

        if (!data)
                return;

        pr_debug("pmi: unregistering handler %p\n", handler);

        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");