arch/powerpc/platforms/powernv/opal-prd.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * OPAL Runtime Diagnostics interface driver
  * Supported on POWERNV platform
  *
  * Copyright IBM Corporation 2015
  */

 #define pr_fmt(fmt) "opal-prd: " fmt

 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/miscdevice.h>
 #include <linux/fs.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/poll.h>
 #include <linux/mm.h>
 #include <linux/slab.h>
 #include <asm/opal-prd.h>
 #include <asm/opal.h>
 #include <asm/io.h>
 #include <linux/uaccess.h>


 /*
  * The msg member must be at the end of the struct, as it's followed by the
  * message data.
  */
 struct opal_prd_msg_queue_item {
 	struct list_head		list;
 	struct opal_prd_msg_header	msg;
 };

 static struct device_node *prd_node;
 static LIST_HEAD(opal_prd_msg_queue);
 static DEFINE_SPINLOCK(opal_prd_msg_queue_lock);
 static DECLARE_WAIT_QUEUE_HEAD(opal_prd_msg_wait);
 static atomic_t prd_usage;

 static bool opal_prd_range_is_valid(uint64_t addr, uint64_t size)
 {
 	struct device_node *parent, *node;
 	bool found;

 	if (addr + size < addr)
 		return false;

 	parent = of_find_node_by_path("/reserved-memory");
 	if (!parent)
 		return false;

 	found = false;

 	for_each_child_of_node(parent, node) {
 		uint64_t range_addr, range_size, range_end;
 		const __be32 *addrp;
 		const char *label;

 		addrp = of_get_address(node, 0, &range_size, NULL);

 		range_addr = of_read_number(addrp, 2);
 		range_end = range_addr + range_size;

 		label = of_get_property(node, "ibm,prd-label", NULL);

 		/* PRD ranges need a label */
 		if (!label)
 			continue;

 		if (range_end <= range_addr)
 			continue;

 		if (addr >= range_addr && addr + size <= range_end) {
 			found = true;
 			of_node_put(node);
 			break;
 		}
 	}

 	of_node_put(parent);
 	return found;
 }

 static int opal_prd_open(struct inode *inode, struct file *file)
 {
 	/*
 	 * Prevent multiple (separate) processes from concurrent interactions
 	 * with the FW PRD channel
 	 */
 	if (atomic_xchg(&prd_usage, 1) == 1)
 		return -EBUSY;

 	return 0;
 }

 /*
  * opal_prd_mmap - maps firmware-provided ranges into userspace
  * @file: file structure for the device
  * @vma: VMA to map the registers into
  */

 static int opal_prd_mmap(struct file *file, struct vm_area_struct *vma)
 {
 	size_t addr, size;
 	pgprot_t page_prot;

 	pr_devel("opal_prd_mmap(0x%016lx, 0x%016lx, 0x%lx, 0x%lx)\n",
 			vma->vm_start, vma->vm_end, vma->vm_pgoff,
 			vma->vm_flags);

 	addr = vma->vm_pgoff << PAGE_SHIFT;
 	size = vma->vm_end - vma->vm_start;

 	/* ensure we're mapping within one of the allowable ranges */
 	if (!opal_prd_range_is_valid(addr, size))
 		return -EINVAL;

 	page_prot = phys_mem_access_prot(file, vma->vm_pgoff,
 					 size, vma->vm_page_prot);

 	return remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff, size,
 				page_prot);
 }

 static bool opal_msg_queue_empty(void)
 {
 	unsigned long flags;
 	bool ret;

 	spin_lock_irqsave(&opal_prd_msg_queue_lock, flags);
 	ret = list_empty(&opal_prd_msg_queue);
 	spin_unlock_irqrestore(&opal_prd_msg_queue_lock, flags);

 	return ret;
 }

 static __poll_t opal_prd_poll(struct file *file,
 		struct poll_table_struct *wait)
 {
 	poll_wait(file, &opal_prd_msg_wait, wait);

 	if (!opal_msg_queue_empty())
 		return EPOLLIN | EPOLLRDNORM;

 	return 0;
 }

 static ssize_t opal_prd_read(struct file *file, char __user *buf,
 		size_t count, loff_t *ppos)
 {
 	struct opal_prd_msg_queue_item *item;
 	unsigned long flags;
 	ssize_t size, err;
 	int rc;

 	/* we need at least a header's worth of data */
 	if (count < sizeof(item->msg))
 		return -EINVAL;

 	if (*ppos)
 		return -ESPIPE;

 	item = NULL;

 	for (;;) {

 		spin_lock_irqsave(&opal_prd_msg_queue_lock, flags);
 		if (!list_empty(&opal_prd_msg_queue)) {
 			item = list_first_entry(&opal_prd_msg_queue,
 					struct opal_prd_msg_queue_item, list);
 			list_del(&item->list);
 		}
 		spin_unlock_irqrestore(&opal_prd_msg_queue_lock, flags);

 		if (item)
 			break;

 		if (file->f_flags & O_NONBLOCK)
 			return -EAGAIN;

 		rc = wait_event_interruptible(opal_prd_msg_wait,
 				!opal_msg_queue_empty());
 		if (rc)
 			return -EINTR;
 	}

 	size = be16_to_cpu(item->msg.size);
 	if (size > count) {
 		err = -EINVAL;
 		goto err_requeue;
 	}

 	rc = copy_to_user(buf, &item->msg, size);
 	if (rc) {
 		err = -EFAULT;
 		goto err_requeue;
 	}

 	kfree(item);

 	return size;

 err_requeue:
 	/* eep! re-queue at the head of the list */
 	spin_lock_irqsave(&opal_prd_msg_queue_lock, flags);
 	list_add(&item->list, &opal_prd_msg_queue);
 	spin_unlock_irqrestore(&opal_prd_msg_queue_lock, flags);
 	return err;
 }

 static ssize_t opal_prd_write(struct file *file, const char __user *buf,
 		size_t count, loff_t *ppos)
 {
 	struct opal_prd_msg_header hdr;
 	ssize_t size;
 	void *msg;
 	int rc;

 	size = sizeof(hdr);

 	if (count < size)
 		return -EINVAL;

 	/* grab the header */
 	rc = copy_from_user(&hdr, buf, sizeof(hdr));
 	if (rc)
 		return -EFAULT;

 	size = be16_to_cpu(hdr.size);

 	msg = memdup_user(buf, size);
 	if (IS_ERR(msg))
 		return PTR_ERR(msg);

 	rc = opal_prd_msg(msg);
 	if (rc) {
 		pr_warn("write: opal_prd_msg returned %d\n", rc);
 		size = -EIO;
 	}

 	kfree(msg);

 	return size;
 }

 static int opal_prd_release(struct inode *inode, struct file *file)
 {
 	struct opal_prd_msg_header msg;

 	msg.size = cpu_to_be16(sizeof(msg));
 	msg.type = OPAL_PRD_MSG_TYPE_FINI;

 	opal_prd_msg((struct opal_prd_msg *)&msg);

 	atomic_xchg(&prd_usage, 0);

 	return 0;
 }

 static long opal_prd_ioctl(struct file *file, unsigned int cmd,
 		unsigned long param)
 {
 	struct opal_prd_info info;
 	struct opal_prd_scom scom;
 	int rc = 0;

 	switch (cmd) {
 	case OPAL_PRD_GET_INFO:
 		memset(&info, 0, sizeof(info));
 		info.version = OPAL_PRD_KERNEL_VERSION;
 		rc = copy_to_user((void __user *)param, &info, sizeof(info));
 		if (rc)
 			return -EFAULT;
 		break;

 	case OPAL_PRD_SCOM_READ:
 		rc = copy_from_user(&scom, (void __user *)param, sizeof(scom));
 		if (rc)
 			return -EFAULT;

 		scom.rc = opal_xscom_read(scom.chip, scom.addr,
 				(__be64 *)&scom.data);
 		scom.data = be64_to_cpu(scom.data);
 		pr_devel("ioctl SCOM_READ: chip %llx addr %016llx data %016llx rc %lld\n",
 				scom.chip, scom.addr, scom.data, scom.rc);

 		rc = copy_to_user((void __user *)param, &scom, sizeof(scom));
 		if (rc)
 			return -EFAULT;
 		break;

 	case OPAL_PRD_SCOM_WRITE:
 		rc = copy_from_user(&scom, (void __user *)param, sizeof(scom));
 		if (rc)
 			return -EFAULT;

 		scom.rc = opal_xscom_write(scom.chip, scom.addr, scom.data);
 		pr_devel("ioctl SCOM_WRITE: chip %llx addr %016llx data %016llx rc %lld\n",
 				scom.chip, scom.addr, scom.data, scom.rc);

 		rc = copy_to_user((void __user *)param, &scom, sizeof(scom));
 		if (rc)
 			return -EFAULT;
 		break;

 	default:
 		rc = -EINVAL;
 	}

 	return rc;
 }

 static const struct file_operations opal_prd_fops = {
 	.open		= opal_prd_open,
 	.mmap		= opal_prd_mmap,
 	.poll		= opal_prd_poll,
 	.read		= opal_prd_read,
 	.write		= opal_prd_write,
 	.unlocked_ioctl	= opal_prd_ioctl,
 	.release	= opal_prd_release,
 	.owner		= THIS_MODULE,
 };

 static struct miscdevice opal_prd_dev = {
 	.minor		= MISC_DYNAMIC_MINOR,
 	.name		= "opal-prd",
 	.fops		= &opal_prd_fops,
 };

 /* opal interface */
 static int opal_prd_msg_notifier(struct notifier_block *nb,
 		unsigned long msg_type, void *_msg)
 {
 	struct opal_prd_msg_queue_item *item;
 	struct opal_prd_msg_header *hdr;
 	struct opal_msg *msg = _msg;
 	int msg_size, item_size;
 	unsigned long flags;

 	if (msg_type != OPAL_MSG_PRD && msg_type != OPAL_MSG_PRD2)
 		return 0;

 	/* Calculate total size of the message and item we need to store. The
 	 * 'size' field in the header includes the header itself. */
 	hdr = (void *)msg->params;
 	msg_size = be16_to_cpu(hdr->size);
 	item_size = msg_size + sizeof(*item) - sizeof(item->msg);

 	item = kzalloc(item_size, GFP_ATOMIC);
 	if (!item)
 		return -ENOMEM;

 	memcpy(&item->msg, msg->params, msg_size);

 	spin_lock_irqsave(&opal_prd_msg_queue_lock, flags);
 	list_add_tail(&item->list, &opal_prd_msg_queue);
 	spin_unlock_irqrestore(&opal_prd_msg_queue_lock, flags);

 	wake_up_interruptible(&opal_prd_msg_wait);

 	return 0;
 }

 static struct notifier_block opal_prd_event_nb = {
 	.notifier_call	= opal_prd_msg_notifier,
 	.next		= NULL,
 	.priority	= 0,
 };

 static struct notifier_block opal_prd_event_nb2 = {
 	.notifier_call	= opal_prd_msg_notifier,
 	.next		= NULL,
 	.priority	= 0,
 };

 static int opal_prd_probe(struct platform_device *pdev)
 {
 	int rc;

 	if (!pdev || !pdev->dev.of_node)
 		return -ENODEV;

 	/* We should only have one prd driver instance per machine; ensure
 	 * that we only get a valid probe on a single OF node.
 	 */
 	if (prd_node)
 		return -EBUSY;

 	prd_node = pdev->dev.of_node;

 	rc = opal_message_notifier_register(OPAL_MSG_PRD, &opal_prd_event_nb);
 	if (rc) {
 		pr_err("Couldn't register event notifier\n");
 		return rc;
 	}

 	rc = opal_message_notifier_register(OPAL_MSG_PRD2, &opal_prd_event_nb2);
 	if (rc) {
 		pr_err("Couldn't register PRD2 event notifier\n");
 		opal_message_notifier_unregister(OPAL_MSG_PRD, &opal_prd_event_nb);
 		return rc;
 	}

 	rc = misc_register(&opal_prd_dev);
 	if (rc) {
 		pr_err("failed to register miscdev\n");
 		opal_message_notifier_unregister(OPAL_MSG_PRD,
 				&opal_prd_event_nb);
 		opal_message_notifier_unregister(OPAL_MSG_PRD2,
 				&opal_prd_event_nb2);
 		return rc;
 	}

 	return 0;
 }

 static int opal_prd_remove(struct platform_device *pdev)
 {
 	misc_deregister(&opal_prd_dev);
 	opal_message_notifier_unregister(OPAL_MSG_PRD, &opal_prd_event_nb);
 	opal_message_notifier_unregister(OPAL_MSG_PRD2, &opal_prd_event_nb2);
 	return 0;
 }

 static const struct of_device_id opal_prd_match[] = {
 	{ .compatible = "ibm,opal-prd" },
 	{ },
 };

 static struct platform_driver opal_prd_driver = {
 	.driver = {
 		.name		= "opal-prd",
 		.of_match_table	= opal_prd_match,
 	},
 	.probe	= opal_prd_probe,
 	.remove	= opal_prd_remove,
 };

 module_platform_driver(opal_prd_driver);

 MODULE_DEVICE_TABLE(of, opal_prd_match);
 MODULE_DESCRIPTION("PowerNV OPAL runtime diagnostic driver");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* OPAL Runtime Diagnostics interface driver
	* Supported on POWERNV platform
	*
	* Copyright IBM Corporation 2015
	*/

	#define pr_fmt(fmt) "opal-prd: " fmt

	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/platform_device.h>
	#include <linux/miscdevice.h>
	#include <linux/fs.h>
	#include <linux/of.h>
	#include <linux/of_address.h>
	#include <linux/poll.h>
	#include <linux/mm.h>
	#include <linux/slab.h>
	#include <asm/opal-prd.h>
	#include <asm/opal.h>
	#include <asm/io.h>
	#include <linux/uaccess.h>


	/*
	* The msg member must be at the end of the struct, as it's followed by the
	* message data.
	*/
	struct opal_prd_msg_queue_item {
	struct list_head list;
	struct opal_prd_msg_header msg;
	};

	static struct device_node *prd_node;
	static LIST_HEAD(opal_prd_msg_queue);
	static DEFINE_SPINLOCK(opal_prd_msg_queue_lock);
	static DECLARE_WAIT_QUEUE_HEAD(opal_prd_msg_wait);
	static atomic_t prd_usage;

	static bool opal_prd_range_is_valid(uint64_t addr, uint64_t size)
	{
	struct device_node parent, node;
	bool found;

	if (addr + size < addr)
	return false;

	parent = of_find_node_by_path("/reserved-memory");
	if (!parent)
	return false;

	found = false;

	for_each_child_of_node(parent, node) {
	uint64_t range_addr, range_size, range_end;
	const __be32 *addrp;
	const char *label;

	addrp = of_get_address(node, 0, &range_size, NULL);

	range_addr = of_read_number(addrp, 2);
	range_end = range_addr + range_size;

	label = of_get_property(node, "ibm,prd-label", NULL);

	/* PRD ranges need a label */
	if (!label)
	continue;

	if (range_end <= range_addr)
	continue;

	if (addr >= range_addr && addr + size <= range_end) {
	found = true;
	of_node_put(node);
	break;
	}
	}

	of_node_put(parent);
	return found;
	}

	static int opal_prd_open(struct inode inode, struct file file)
	{
	/*
	* Prevent multiple (separate) processes from concurrent interactions
	* with the FW PRD channel
	*/
	if (atomic_xchg(&prd_usage, 1) == 1)
	return -EBUSY;

	return 0;
	}

	/*
	* opal_prd_mmap - maps firmware-provided ranges into userspace
	* @file: file structure for the device
	* @vma: VMA to map the registers into
	*/

	static int opal_prd_mmap(struct file file, struct vm_area_struct vma)
	{
	size_t addr, size;
	pgprot_t page_prot;

	pr_devel("opal_prd_mmap(0x%016lx, 0x%016lx, 0x%lx, 0x%lx)\n",
	vma->vm_start, vma->vm_end, vma->vm_pgoff,
	vma->vm_flags);

	addr = vma->vm_pgoff << PAGE_SHIFT;
	size = vma->vm_end - vma->vm_start;

	/* ensure we're mapping within one of the allowable ranges */
	if (!opal_prd_range_is_valid(addr, size))
	return -EINVAL;

	page_prot = phys_mem_access_prot(file, vma->vm_pgoff,
	size, vma->vm_page_prot);

	return remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff, size,
	page_prot);
	}

	static bool opal_msg_queue_empty(void)
	{
	unsigned long flags;
	bool ret;

	spin_lock_irqsave(&opal_prd_msg_queue_lock, flags);
	ret = list_empty(&opal_prd_msg_queue);
	spin_unlock_irqrestore(&opal_prd_msg_queue_lock, flags);

	return ret;
	}

	static __poll_t opal_prd_poll(struct file *file,
	struct poll_table_struct *wait)
	{
	poll_wait(file, &opal_prd_msg_wait, wait);

	if (!opal_msg_queue_empty())
	return EPOLLIN \| EPOLLRDNORM;

	return 0;
	}

	static ssize_t opal_prd_read(struct file file, char __user buf,
	size_t count, loff_t *ppos)
	{
	struct opal_prd_msg_queue_item *item;
	unsigned long flags;
	ssize_t size, err;
	int rc;

	/* we need at least a header's worth of data */
	if (count < sizeof(item->msg))
	return -EINVAL;

	if (*ppos)
	return -ESPIPE;

	item = NULL;

	for (;;) {

	spin_lock_irqsave(&opal_prd_msg_queue_lock, flags);
	if (!list_empty(&opal_prd_msg_queue)) {
	item = list_first_entry(&opal_prd_msg_queue,
	struct opal_prd_msg_queue_item, list);
	list_del(&item->list);
	}
	spin_unlock_irqrestore(&opal_prd_msg_queue_lock, flags);

	if (item)
	break;

	if (file->f_flags & O_NONBLOCK)
	return -EAGAIN;

	rc = wait_event_interruptible(opal_prd_msg_wait,
	!opal_msg_queue_empty());
	if (rc)
	return -EINTR;
	}

	size = be16_to_cpu(item->msg.size);
	if (size > count) {
	err = -EINVAL;
	goto err_requeue;
	}

	rc = copy_to_user(buf, &item->msg, size);
	if (rc) {
	err = -EFAULT;
	goto err_requeue;
	}

	kfree(item);

	return size;

	err_requeue:
	/* eep! re-queue at the head of the list */
	spin_lock_irqsave(&opal_prd_msg_queue_lock, flags);
	list_add(&item->list, &opal_prd_msg_queue);
	spin_unlock_irqrestore(&opal_prd_msg_queue_lock, flags);
	return err;
	}

	static ssize_t opal_prd_write(struct file file, const char __user buf,
	size_t count, loff_t *ppos)
	{
	struct opal_prd_msg_header hdr;
	ssize_t size;
	void *msg;
	int rc;

	size = sizeof(hdr);

	if (count < size)
	return -EINVAL;

	/* grab the header */
	rc = copy_from_user(&hdr, buf, sizeof(hdr));
	if (rc)
	return -EFAULT;

	size = be16_to_cpu(hdr.size);

	msg = memdup_user(buf, size);
	if (IS_ERR(msg))
	return PTR_ERR(msg);

	rc = opal_prd_msg(msg);
	if (rc) {
	pr_warn("write: opal_prd_msg returned %d\n", rc);
	size = -EIO;
	}

	kfree(msg);

	return size;
	}

	static int opal_prd_release(struct inode inode, struct file file)
	{
	struct opal_prd_msg_header msg;

	msg.size = cpu_to_be16(sizeof(msg));
	msg.type = OPAL_PRD_MSG_TYPE_FINI;

	opal_prd_msg((struct opal_prd_msg *)&msg);

	atomic_xchg(&prd_usage, 0);

	return 0;
	}

	static long opal_prd_ioctl(struct file *file, unsigned int cmd,
	unsigned long param)
	{
	struct opal_prd_info info;
	struct opal_prd_scom scom;
	int rc = 0;

	switch (cmd) {
	case OPAL_PRD_GET_INFO:
	memset(&info, 0, sizeof(info));
	info.version = OPAL_PRD_KERNEL_VERSION;
	rc = copy_to_user((void __user *)param, &info, sizeof(info));
	if (rc)
	return -EFAULT;
	break;

	case OPAL_PRD_SCOM_READ:
	rc = copy_from_user(&scom, (void __user *)param, sizeof(scom));
	if (rc)
	return -EFAULT;

	scom.rc = opal_xscom_read(scom.chip, scom.addr,
	(__be64 *)&scom.data);
	scom.data = be64_to_cpu(scom.data);
	pr_devel("ioctl SCOM_READ: chip %llx addr %016llx data %016llx rc %lld\n",
	scom.chip, scom.addr, scom.data, scom.rc);

	rc = copy_to_user((void __user *)param, &scom, sizeof(scom));
	if (rc)
	return -EFAULT;
	break;

	case OPAL_PRD_SCOM_WRITE:
	rc = copy_from_user(&scom, (void __user *)param, sizeof(scom));
	if (rc)
	return -EFAULT;

	scom.rc = opal_xscom_write(scom.chip, scom.addr, scom.data);
	pr_devel("ioctl SCOM_WRITE: chip %llx addr %016llx data %016llx rc %lld\n",
	scom.chip, scom.addr, scom.data, scom.rc);

	rc = copy_to_user((void __user *)param, &scom, sizeof(scom));
	if (rc)
	return -EFAULT;
	break;

	default:
	rc = -EINVAL;
	}

	return rc;
	}

	static const struct file_operations opal_prd_fops = {
	.open = opal_prd_open,
	.mmap = opal_prd_mmap,
	.poll = opal_prd_poll,
	.read = opal_prd_read,
	.write = opal_prd_write,
	.unlocked_ioctl = opal_prd_ioctl,
	.release = opal_prd_release,
	.owner = THIS_MODULE,
	};

	static struct miscdevice opal_prd_dev = {
	.minor = MISC_DYNAMIC_MINOR,
	.name = "opal-prd",
	.fops = &opal_prd_fops,
	};

	/* opal interface */
	static int opal_prd_msg_notifier(struct notifier_block *nb,
	unsigned long msg_type, void *_msg)
	{
	struct opal_prd_msg_queue_item *item;
	struct opal_prd_msg_header *hdr;
	struct opal_msg *msg = _msg;
	int msg_size, item_size;
	unsigned long flags;

	if (msg_type != OPAL_MSG_PRD && msg_type != OPAL_MSG_PRD2)
	return 0;

	/* Calculate total size of the message and item we need to store. The
	* 'size' field in the header includes the header itself. */
	hdr = (void *)msg->params;
	msg_size = be16_to_cpu(hdr->size);
	item_size = msg_size + sizeof(*item) - sizeof(item->msg);

	item = kzalloc(item_size, GFP_ATOMIC);
	if (!item)
	return -ENOMEM;

	memcpy(&item->msg, msg->params, msg_size);

	spin_lock_irqsave(&opal_prd_msg_queue_lock, flags);
	list_add_tail(&item->list, &opal_prd_msg_queue);
	spin_unlock_irqrestore(&opal_prd_msg_queue_lock, flags);

	wake_up_interruptible(&opal_prd_msg_wait);

	return 0;
	}

	static struct notifier_block opal_prd_event_nb = {
	.notifier_call = opal_prd_msg_notifier,
	.next = NULL,
	.priority = 0,
	};

	static struct notifier_block opal_prd_event_nb2 = {
	.notifier_call = opal_prd_msg_notifier,
	.next = NULL,
	.priority = 0,
	};

	static int opal_prd_probe(struct platform_device *pdev)
	{
	int rc;

	if (!pdev \|\| !pdev->dev.of_node)
	return -ENODEV;

	/* We should only have one prd driver instance per machine; ensure
	* that we only get a valid probe on a single OF node.
	*/
	if (prd_node)
	return -EBUSY;

	prd_node = pdev->dev.of_node;

	rc = opal_message_notifier_register(OPAL_MSG_PRD, &opal_prd_event_nb);
	if (rc) {
	pr_err("Couldn't register event notifier\n");
	return rc;
	}

	rc = opal_message_notifier_register(OPAL_MSG_PRD2, &opal_prd_event_nb2);
	if (rc) {
	pr_err("Couldn't register PRD2 event notifier\n");
	opal_message_notifier_unregister(OPAL_MSG_PRD, &opal_prd_event_nb);
	return rc;
	}

	rc = misc_register(&opal_prd_dev);
	if (rc) {
	pr_err("failed to register miscdev\n");
	opal_message_notifier_unregister(OPAL_MSG_PRD,
	&opal_prd_event_nb);
	opal_message_notifier_unregister(OPAL_MSG_PRD2,
	&opal_prd_event_nb2);
	return rc;
	}

	return 0;
	}

	static int opal_prd_remove(struct platform_device *pdev)
	{
	misc_deregister(&opal_prd_dev);
	opal_message_notifier_unregister(OPAL_MSG_PRD, &opal_prd_event_nb);
	opal_message_notifier_unregister(OPAL_MSG_PRD2, &opal_prd_event_nb2);
	return 0;
	}

	static const struct of_device_id opal_prd_match[] = {
	{ .compatible = "ibm,opal-prd" },
	{ },
	};

	static struct platform_driver opal_prd_driver = {
	.driver = {
	.name = "opal-prd",
	.of_match_table = opal_prd_match,
	},
	.probe = opal_prd_probe,
	.remove = opal_prd_remove,
	};

	module_platform_driver(opal_prd_driver);

	MODULE_DEVICE_TABLE(of, opal_prd_match);
	MODULE_DESCRIPTION("PowerNV OPAL runtime diagnostic driver");
	MODULE_LICENSE("GPL");