1 // SPDX-License-Identifier: GPL-2.0-only
3 * OPAL Runtime Diagnostics interface driver
4 * Supported on POWERNV platform
6 * Copyright IBM Corporation 2015
9 #define pr_fmt(fmt) "opal-prd: " fmt
11 #include <linux/kernel.h>
12 #include <linux/module.h>
13 #include <linux/platform_device.h>
14 #include <linux/miscdevice.h>
17 #include <linux/of_address.h>
18 #include <linux/poll.h>
20 #include <linux/slab.h>
21 #include <asm/opal-prd.h>
24 #include <linux/uaccess.h>
29 struct opal_prd_msg_header header;
30 DECLARE_FLEX_ARRAY(u8, data);
35 * The msg member must be at the end of the struct, as it's followed by the
38 struct opal_prd_msg_queue_item {
39 struct list_head list;
40 struct opal_prd_msg msg;
43 static struct device_node *prd_node;
44 static LIST_HEAD(opal_prd_msg_queue);
45 static DEFINE_SPINLOCK(opal_prd_msg_queue_lock);
46 static DECLARE_WAIT_QUEUE_HEAD(opal_prd_msg_wait);
47 static atomic_t prd_usage;
49 static bool opal_prd_range_is_valid(uint64_t addr, uint64_t size)
51 struct device_node *parent, *node;
54 if (addr + size < addr)
57 parent = of_find_node_by_path("/reserved-memory");
63 for_each_child_of_node(parent, node) {
64 uint64_t range_addr, range_size, range_end;
68 addrp = of_get_address(node, 0, &range_size, NULL);
70 range_addr = of_read_number(addrp, 2);
71 range_end = range_addr + range_size;
73 label = of_get_property(node, "ibm,prd-label", NULL);
75 /* PRD ranges need a label */
79 if (range_end <= range_addr)
82 if (addr >= range_addr && addr + size <= range_end) {
93 static int opal_prd_open(struct inode *inode, struct file *file)
96 * Prevent multiple (separate) processes from concurrent interactions
97 * with the FW PRD channel
99 if (atomic_xchg(&prd_usage, 1) == 1)
106 * opal_prd_mmap - maps firmware-provided ranges into userspace
107 * @file: file structure for the device
108 * @vma: VMA to map the registers into
111 static int opal_prd_mmap(struct file *file, struct vm_area_struct *vma)
116 pr_devel("opal_prd_mmap(0x%016lx, 0x%016lx, 0x%lx, 0x%lx)\n",
117 vma->vm_start, vma->vm_end, vma->vm_pgoff,
120 addr = vma->vm_pgoff << PAGE_SHIFT;
121 size = vma->vm_end - vma->vm_start;
123 /* ensure we're mapping within one of the allowable ranges */
124 if (!opal_prd_range_is_valid(addr, size))
127 page_prot = phys_mem_access_prot(file, vma->vm_pgoff,
128 size, vma->vm_page_prot);
130 return remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff, size,
134 static bool opal_msg_queue_empty(void)
139 spin_lock_irqsave(&opal_prd_msg_queue_lock, flags);
140 ret = list_empty(&opal_prd_msg_queue);
141 spin_unlock_irqrestore(&opal_prd_msg_queue_lock, flags);
146 static __poll_t opal_prd_poll(struct file *file,
147 struct poll_table_struct *wait)
149 poll_wait(file, &opal_prd_msg_wait, wait);
151 if (!opal_msg_queue_empty())
152 return EPOLLIN | EPOLLRDNORM;
157 static ssize_t opal_prd_read(struct file *file, char __user *buf,
158 size_t count, loff_t *ppos)
160 struct opal_prd_msg_queue_item *item;
165 /* we need at least a header's worth of data */
166 if (count < sizeof(item->msg.header))
176 spin_lock_irqsave(&opal_prd_msg_queue_lock, flags);
177 if (!list_empty(&opal_prd_msg_queue)) {
178 item = list_first_entry(&opal_prd_msg_queue,
179 struct opal_prd_msg_queue_item, list);
180 list_del(&item->list);
182 spin_unlock_irqrestore(&opal_prd_msg_queue_lock, flags);
187 if (file->f_flags & O_NONBLOCK)
190 rc = wait_event_interruptible(opal_prd_msg_wait,
191 !opal_msg_queue_empty());
196 size = be16_to_cpu(item->msg.header.size);
202 rc = copy_to_user(buf, &item->msg, size);
213 /* eep! re-queue at the head of the list */
214 spin_lock_irqsave(&opal_prd_msg_queue_lock, flags);
215 list_add(&item->list, &opal_prd_msg_queue);
216 spin_unlock_irqrestore(&opal_prd_msg_queue_lock, flags);
220 static ssize_t opal_prd_write(struct file *file, const char __user *buf,
221 size_t count, loff_t *ppos)
223 struct opal_prd_msg_header hdr;
224 struct opal_prd_msg *msg;
233 /* grab the header */
234 rc = copy_from_user(&hdr, buf, sizeof(hdr));
238 size = be16_to_cpu(hdr.size);
240 msg = memdup_user(buf, size);
244 rc = opal_prd_msg(msg);
246 pr_warn("write: opal_prd_msg returned %d\n", rc);
255 static int opal_prd_release(struct inode *inode, struct file *file)
257 struct opal_prd_msg msg;
259 msg.header.size = cpu_to_be16(sizeof(msg));
260 msg.header.type = OPAL_PRD_MSG_TYPE_FINI;
264 atomic_xchg(&prd_usage, 0);
269 static long opal_prd_ioctl(struct file *file, unsigned int cmd,
272 struct opal_prd_info info;
273 struct opal_prd_scom scom;
277 case OPAL_PRD_GET_INFO:
278 memset(&info, 0, sizeof(info));
279 info.version = OPAL_PRD_KERNEL_VERSION;
280 rc = copy_to_user((void __user *)param, &info, sizeof(info));
285 case OPAL_PRD_SCOM_READ:
286 rc = copy_from_user(&scom, (void __user *)param, sizeof(scom));
290 scom.rc = opal_xscom_read(scom.chip, scom.addr,
291 (__be64 *)&scom.data);
292 scom.data = be64_to_cpu(scom.data);
293 pr_devel("ioctl SCOM_READ: chip %llx addr %016llx data %016llx rc %lld\n",
294 scom.chip, scom.addr, scom.data, scom.rc);
296 rc = copy_to_user((void __user *)param, &scom, sizeof(scom));
301 case OPAL_PRD_SCOM_WRITE:
302 rc = copy_from_user(&scom, (void __user *)param, sizeof(scom));
306 scom.rc = opal_xscom_write(scom.chip, scom.addr, scom.data);
307 pr_devel("ioctl SCOM_WRITE: chip %llx addr %016llx data %016llx rc %lld\n",
308 scom.chip, scom.addr, scom.data, scom.rc);
310 rc = copy_to_user((void __user *)param, &scom, sizeof(scom));
322 static const struct file_operations opal_prd_fops = {
323 .open = opal_prd_open,
324 .mmap = opal_prd_mmap,
325 .poll = opal_prd_poll,
326 .read = opal_prd_read,
327 .write = opal_prd_write,
328 .unlocked_ioctl = opal_prd_ioctl,
329 .release = opal_prd_release,
330 .owner = THIS_MODULE,
333 static struct miscdevice opal_prd_dev = {
334 .minor = MISC_DYNAMIC_MINOR,
336 .fops = &opal_prd_fops,
340 static int opal_prd_msg_notifier(struct notifier_block *nb,
341 unsigned long msg_type, void *_msg)
343 struct opal_prd_msg_queue_item *item;
344 struct opal_prd_msg_header *hdr;
345 struct opal_msg *msg = _msg;
346 int msg_size, item_size;
349 if (msg_type != OPAL_MSG_PRD && msg_type != OPAL_MSG_PRD2)
352 /* Calculate total size of the message and item we need to store. The
353 * 'size' field in the header includes the header itself. */
354 hdr = (void *)msg->params;
355 msg_size = be16_to_cpu(hdr->size);
356 item_size = msg_size + sizeof(*item) - sizeof(item->msg);
358 item = kzalloc(item_size, GFP_ATOMIC);
362 memcpy(&item->msg.data, msg->params, msg_size);
364 spin_lock_irqsave(&opal_prd_msg_queue_lock, flags);
365 list_add_tail(&item->list, &opal_prd_msg_queue);
366 spin_unlock_irqrestore(&opal_prd_msg_queue_lock, flags);
368 wake_up_interruptible(&opal_prd_msg_wait);
373 static struct notifier_block opal_prd_event_nb = {
374 .notifier_call = opal_prd_msg_notifier,
379 static struct notifier_block opal_prd_event_nb2 = {
380 .notifier_call = opal_prd_msg_notifier,
385 static int opal_prd_probe(struct platform_device *pdev)
389 if (!pdev || !pdev->dev.of_node)
392 /* We should only have one prd driver instance per machine; ensure
393 * that we only get a valid probe on a single OF node.
398 prd_node = pdev->dev.of_node;
400 rc = opal_message_notifier_register(OPAL_MSG_PRD, &opal_prd_event_nb);
402 pr_err("Couldn't register event notifier\n");
406 rc = opal_message_notifier_register(OPAL_MSG_PRD2, &opal_prd_event_nb2);
408 pr_err("Couldn't register PRD2 event notifier\n");
409 opal_message_notifier_unregister(OPAL_MSG_PRD, &opal_prd_event_nb);
413 rc = misc_register(&opal_prd_dev);
415 pr_err("failed to register miscdev\n");
416 opal_message_notifier_unregister(OPAL_MSG_PRD,
418 opal_message_notifier_unregister(OPAL_MSG_PRD2,
419 &opal_prd_event_nb2);
426 static int opal_prd_remove(struct platform_device *pdev)
428 misc_deregister(&opal_prd_dev);
429 opal_message_notifier_unregister(OPAL_MSG_PRD, &opal_prd_event_nb);
430 opal_message_notifier_unregister(OPAL_MSG_PRD2, &opal_prd_event_nb2);
434 static const struct of_device_id opal_prd_match[] = {
435 { .compatible = "ibm,opal-prd" },
439 static struct platform_driver opal_prd_driver = {
442 .of_match_table = opal_prd_match,
444 .probe = opal_prd_probe,
445 .remove = opal_prd_remove,
448 module_platform_driver(opal_prd_driver);
450 MODULE_DEVICE_TABLE(of, opal_prd_match);
451 MODULE_DESCRIPTION("PowerNV OPAL runtime diagnostic driver");
452 MODULE_LICENSE("GPL");