blob: 24f04f20d3e85c58a167fd6c639e72f09677f34a [file] [log] [blame]
// 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>
struct opal_prd_msg {
union {
struct opal_prd_msg_header header;
DECLARE_FLEX_ARRAY(u8, data);
};
};
/*
* 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 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);
if (!addrp)
continue;
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.header))
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.header.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;
struct opal_prd_msg *msg;
ssize_t size;
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 msg;
msg.header.size = cpu_to_be16(sizeof(msg));
msg.header.type = OPAL_PRD_MSG_TYPE_FINI;
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.data, 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 void 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);
}
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_new = 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");