1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * OPAL Runtime Diagnostics interface driver
4 * Supported on POWERNV platform
5 *
6 * Copyright IBM Corporation 2015
7 */
8
9 #define pr_fmt(fmt) "opal-prd: " fmt
10
11 #include <linux/kernel.h>
12 #include <linux/module.h>
13 #include <linux/platform_device.h>
14 #include <linux/miscdevice.h>
15 #include <linux/fs.h>
16 #include <linux/of.h>
17 #include <linux/of_address.h>
18 #include <linux/poll.h>
19 #include <linux/mm.h>
20 #include <linux/slab.h>
21 #include <asm/opal-prd.h>
22 #include <asm/opal.h>
23 #include <asm/io.h>
24 #include <linux/uaccess.h>
25
26
27 struct opal_prd_msg {
28 union {
29 struct opal_prd_msg_header header;
30 DECLARE_FLEX_ARRAY(u8, data);
31 };
32 };
33
34 /*
35 * The msg member must be at the end of the struct, as it's followed by the
36 * message data.
37 */
38 struct opal_prd_msg_queue_item {
39 struct list_head list;
40 struct opal_prd_msg msg;
41 };
42
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;
48
49 static bool opal_prd_range_is_valid(uint64_t addr, uint64_t size)
50 {
51 struct device_node *parent, *node;
52 bool found;
53
54 if (addr + size < addr)
55 return false;
56
57 parent = of_find_node_by_path("/reserved-memory");
58 if (!parent)
59 return false;
60
61 found = false;
62
63 for_each_child_of_node(parent, node) {
64 uint64_t range_addr, range_size, range_end;
65 const __be32 *addrp;
66 const char *label;
67
68 addrp = of_get_address(node, 0, &range_size, NULL);
69 if (!addrp)
70 continue;
71
72 range_addr = of_read_number(addrp, 2);
73 range_end = range_addr + range_size;
74
75 label = of_get_property(node, "ibm,prd-label", NULL);
76
77 /* PRD ranges need a label */
78 if (!label)
79 continue;
80
81 if (range_end <= range_addr)
82 continue;
83
84 if (addr >= range_addr && addr + size <= range_end) {
85 found = true;
86 of_node_put(node);
87 break;
88 }
89 }
90
91 of_node_put(parent);
92 return found;
93 }
94
95 static int opal_prd_open(struct inode *inode, struct file *file)
96 {
97 /*
98 * Prevent multiple (separate) processes from concurrent interactions
99 * with the FW PRD channel
100 */
101 if (atomic_xchg(&prd_usage, 1) == 1)
102 return -EBUSY;
103
104 return 0;
105 }
106
107 /*
108 * opal_prd_mmap - maps firmware-provided ranges into userspace
109 * @file: file structure for the device
110 * @vma: VMA to map the registers into
111 */
112
113 static int opal_prd_mmap(struct file *file, struct vm_area_struct *vma)
114 {
115 size_t addr, size;
116 pgprot_t page_prot;
117
118 pr_devel("opal_prd_mmap(0x%016lx, 0x%016lx, 0x%lx, 0x%lx)\n",
119 vma->vm_start, vma->vm_end, vma->vm_pgoff,
120 vma->vm_flags);
121
122 addr = vma->vm_pgoff << PAGE_SHIFT;
123 size = vma->vm_end - vma->vm_start;
124
125 /* ensure we're mapping within one of the allowable ranges */
126 if (!opal_prd_range_is_valid(addr, size))
127 return -EINVAL;
128
129 page_prot = phys_mem_access_prot(file, vma->vm_pgoff,
130 size, vma->vm_page_prot);
131
132 return remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff, size,
133 page_prot);
134 }
135
136 static bool opal_msg_queue_empty(void)
137 {
138 unsigned long flags;
139 bool ret;
140
141 spin_lock_irqsave(&opal_prd_msg_queue_lock, flags);
142 ret = list_empty(&opal_prd_msg_queue);
143 spin_unlock_irqrestore(&opal_prd_msg_queue_lock, flags);
144
145 return ret;
146 }
147
148 static __poll_t opal_prd_poll(struct file *file,
149 struct poll_table_struct *wait)
150 {
151 poll_wait(file, &opal_prd_msg_wait, wait);
152
153 if (!opal_msg_queue_empty())
154 return EPOLLIN | EPOLLRDNORM;
155
156 return 0;
157 }
158
159 static ssize_t opal_prd_read(struct file *file, char __user *buf,
160 size_t count, loff_t *ppos)
161 {
162 struct opal_prd_msg_queue_item *item;
163 unsigned long flags;
164 ssize_t size, err;
165 int rc;
166
167 /* we need at least a header's worth of data */
168 if (count < sizeof(item->msg.header))
169 return -EINVAL;
170
171 if (*ppos)
172 return -ESPIPE;
173
174 item = NULL;
175
176 for (;;) {
177
178 spin_lock_irqsave(&opal_prd_msg_queue_lock, flags);
179 if (!list_empty(&opal_prd_msg_queue)) {
180 item = list_first_entry(&opal_prd_msg_queue,
181 struct opal_prd_msg_queue_item, list);
182 list_del(&item->list);
183 }
184 spin_unlock_irqrestore(&opal_prd_msg_queue_lock, flags);
185
186 if (item)
187 break;
188
189 if (file->f_flags & O_NONBLOCK)
190 return -EAGAIN;
191
192 rc = wait_event_interruptible(opal_prd_msg_wait,
193 !opal_msg_queue_empty());
194 if (rc)
195 return -EINTR;
196 }
197
198 size = be16_to_cpu(item->msg.header.size);
199 if (size > count) {
200 err = -EINVAL;
201 goto err_requeue;
202 }
203
204 rc = copy_to_user(buf, &item->msg, size);
205 if (rc) {
206 err = -EFAULT;
207 goto err_requeue;
208 }
209
210 kfree(item);
211
212 return size;
213
214 err_requeue:
215 /* eep! re-queue at the head of the list */
216 spin_lock_irqsave(&opal_prd_msg_queue_lock, flags);
217 list_add(&item->list, &opal_prd_msg_queue);
218 spin_unlock_irqrestore(&opal_prd_msg_queue_lock, flags);
219 return err;
220 }
221
222 static ssize_t opal_prd_write(struct file *file, const char __user *buf,
223 size_t count, loff_t *ppos)
224 {
225 struct opal_prd_msg_header hdr;
226 struct opal_prd_msg *msg;
227 ssize_t size;
228 int rc;
229
230 size = sizeof(hdr);
231
232 if (count < size)
233 return -EINVAL;
234
235 /* grab the header */
236 rc = copy_from_user(&hdr, buf, sizeof(hdr));
237 if (rc)
238 return -EFAULT;
239
240 size = be16_to_cpu(hdr.size);
241
242 msg = memdup_user(buf, size);
243 if (IS_ERR(msg))
244 return PTR_ERR(msg);
245
246 rc = opal_prd_msg(msg);
247 if (rc) {
248 pr_warn("write: opal_prd_msg returned %d\n", rc);
249 size = -EIO;
250 }
251
252 kfree(msg);
253
254 return size;
255 }
256
257 static int opal_prd_release(struct inode *inode, struct file *file)
258 {
259 struct opal_prd_msg msg;
260
261 msg.header.size = cpu_to_be16(sizeof(msg));
262 msg.header.type = OPAL_PRD_MSG_TYPE_FINI;
263
264 opal_prd_msg(&msg);
265
266 atomic_xchg(&prd_usage, 0);
267
268 return 0;
269 }
270
271 static long opal_prd_ioctl(struct file *file, unsigned int cmd,
272 unsigned long param)
273 {
274 struct opal_prd_info info;
275 struct opal_prd_scom scom;
276 int rc = 0;
277
278 switch (cmd) {
279 case OPAL_PRD_GET_INFO:
280 memset(&info, 0, sizeof(info));
281 info.version = OPAL_PRD_KERNEL_VERSION;
282 rc = copy_to_user((void __user *)param, &info, sizeof(info));
283 if (rc)
284 return -EFAULT;
285 break;
286
287 case OPAL_PRD_SCOM_READ:
288 rc = copy_from_user(&scom, (void __user *)param, sizeof(scom));
289 if (rc)
290 return -EFAULT;
291
292 scom.rc = opal_xscom_read(scom.chip, scom.addr,
293 (__be64 *)&scom.data);
294 scom.data = be64_to_cpu(scom.data);
295 pr_devel("ioctl SCOM_READ: chip %llx addr %016llx data %016llx rc %lld\n",
296 scom.chip, scom.addr, scom.data, scom.rc);
297
298 rc = copy_to_user((void __user *)param, &scom, sizeof(scom));
299 if (rc)
300 return -EFAULT;
301 break;
302
303 case OPAL_PRD_SCOM_WRITE:
304 rc = copy_from_user(&scom, (void __user *)param, sizeof(scom));
305 if (rc)
306 return -EFAULT;
307
308 scom.rc = opal_xscom_write(scom.chip, scom.addr, scom.data);
309 pr_devel("ioctl SCOM_WRITE: chip %llx addr %016llx data %016llx rc %lld\n",
310 scom.chip, scom.addr, scom.data, scom.rc);
311
312 rc = copy_to_user((void __user *)param, &scom, sizeof(scom));
313 if (rc)
314 return -EFAULT;
315 break;
316
317 default:
318 rc = -EINVAL;
319 }
320
321 return rc;
322 }
323
324 static const struct file_operations opal_prd_fops = {
325 .open = opal_prd_open,
326 .mmap = opal_prd_mmap,
327 .poll = opal_prd_poll,
328 .read = opal_prd_read,
329 .write = opal_prd_write,
330 .unlocked_ioctl = opal_prd_ioctl,
331 .release = opal_prd_release,
332 .owner = THIS_MODULE,
333 };
334
335 static struct miscdevice opal_prd_dev = {
336 .minor = MISC_DYNAMIC_MINOR,
337 .name = "opal-prd",
338 .fops = &opal_prd_fops,
339 };
340
341 /* opal interface */
342 static int opal_prd_msg_notifier(struct notifier_block *nb,
343 unsigned long msg_type, void *_msg)
344 {
345 struct opal_prd_msg_queue_item *item;
346 struct opal_prd_msg_header *hdr;
347 struct opal_msg *msg = _msg;
348 int msg_size, item_size;
349 unsigned long flags;
350
351 if (msg_type != OPAL_MSG_PRD && msg_type != OPAL_MSG_PRD2)
352 return 0;
353
354 /* Calculate total size of the message and item we need to store. The
355 * 'size' field in the header includes the header itself. */
356 hdr = (void *)msg->params;
357 msg_size = be16_to_cpu(hdr->size);
358 item_size = msg_size + sizeof(*item) - sizeof(item->msg);
359
360 item = kzalloc(item_size, GFP_ATOMIC);
361 if (!item)
362 return -ENOMEM;
363
364 memcpy(&item->msg.data, msg->params, msg_size);
365
366 spin_lock_irqsave(&opal_prd_msg_queue_lock, flags);
367 list_add_tail(&item->list, &opal_prd_msg_queue);
368 spin_unlock_irqrestore(&opal_prd_msg_queue_lock, flags);
369
370 wake_up_interruptible(&opal_prd_msg_wait);
371
372 return 0;
373 }
374
375 static struct notifier_block opal_prd_event_nb = {
376 .notifier_call = opal_prd_msg_notifier,
377 .next = NULL,
378 .priority = 0,
379 };
380
381 static struct notifier_block opal_prd_event_nb2 = {
382 .notifier_call = opal_prd_msg_notifier,
383 .next = NULL,
384 .priority = 0,
385 };
386
387 static int opal_prd_probe(struct platform_device *pdev)
388 {
389 int rc;
390
391 if (!pdev || !pdev->dev.of_node)
392 return -ENODEV;
393
394 /* We should only have one prd driver instance per machine; ensure
395 * that we only get a valid probe on a single OF node.
396 */
397 if (prd_node)
398 return -EBUSY;
399
400 prd_node = pdev->dev.of_node;
401
402 rc = opal_message_notifier_register(OPAL_MSG_PRD, &opal_prd_event_nb);
403 if (rc) {
404 pr_err("Couldn't register event notifier\n");
405 return rc;
406 }
407
408 rc = opal_message_notifier_register(OPAL_MSG_PRD2, &opal_prd_event_nb2);
409 if (rc) {
410 pr_err("Couldn't register PRD2 event notifier\n");
411 opal_message_notifier_unregister(OPAL_MSG_PRD, &opal_prd_event_nb);
412 return rc;
413 }
414
415 rc = misc_register(&opal_prd_dev);
416 if (rc) {
417 pr_err("failed to register miscdev\n");
418 opal_message_notifier_unregister(OPAL_MSG_PRD,
419 &opal_prd_event_nb);
420 opal_message_notifier_unregister(OPAL_MSG_PRD2,
421 &opal_prd_event_nb2);
422 return rc;
423 }
424
425 return 0;
426 }
427
428 static void opal_prd_remove(struct platform_device *pdev)
429 {
430 misc_deregister(&opal_prd_dev);
431 opal_message_notifier_unregister(OPAL_MSG_PRD, &opal_prd_event_nb);
432 opal_message_notifier_unregister(OPAL_MSG_PRD2, &opal_prd_event_nb2);
433 }
434
435 static const struct of_device_id opal_prd_match[] = {
436 { .compatible = "ibm,opal-prd" },
437 { },
438 };
439
440 static struct platform_driver opal_prd_driver = {
441 .driver = {
442 .name = "opal-prd",
443 .of_match_table = opal_prd_match,
444 },
445 .probe = opal_prd_probe,
446 .remove_new = opal_prd_remove,
447 };
448
449 module_platform_driver(opal_prd_driver);
450
451 MODULE_DEVICE_TABLE(of, opal_prd_match);
452 MODULE_DESCRIPTION("PowerNV OPAL runtime diagnostic driver");
453 MODULE_LICENSE("GPL");
454
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.