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/*
* OPAL Runtime Diagnostics interface driver
* Supported on POWERNV platform
*
* Copyright IBM Corporation 2015
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* 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.
*/
#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;
int rc;
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);
rc = remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff, size,
page_prot);
return rc;
}
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 POLLIN | POLLRDNORM;
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(sco
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