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0d7cd855 JK |
1 | /* |
2 | * OPAL Runtime Diagnostics interface driver | |
3 | * Supported on POWERNV platform | |
4 | * | |
5 | * Copyright IBM Corporation 2015 | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License version 2 as | |
9 | * published by the Free Software Foundation. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | * GNU General Public License for more details. | |
15 | */ | |
16 | ||
17 | #define pr_fmt(fmt) "opal-prd: " fmt | |
18 | ||
19 | #include <linux/kernel.h> | |
20 | #include <linux/module.h> | |
21 | #include <linux/platform_device.h> | |
22 | #include <linux/miscdevice.h> | |
23 | #include <linux/fs.h> | |
24 | #include <linux/of.h> | |
25 | #include <linux/of_address.h> | |
26 | #include <linux/poll.h> | |
27 | #include <linux/mm.h> | |
28 | #include <linux/slab.h> | |
29 | #include <asm/opal-prd.h> | |
30 | #include <asm/opal.h> | |
31 | #include <asm/io.h> | |
32 | #include <asm/uaccess.h> | |
33 | ||
34 | ||
7185795a JK |
35 | /** |
36 | * The msg member must be at the end of the struct, as it's followed by the | |
37 | * message data. | |
38 | */ | |
0d7cd855 | 39 | struct opal_prd_msg_queue_item { |
0d7cd855 | 40 | struct list_head list; |
7185795a | 41 | struct opal_prd_msg_header msg; |
0d7cd855 JK |
42 | }; |
43 | ||
44 | static struct device_node *prd_node; | |
45 | static LIST_HEAD(opal_prd_msg_queue); | |
46 | static DEFINE_SPINLOCK(opal_prd_msg_queue_lock); | |
47 | static DECLARE_WAIT_QUEUE_HEAD(opal_prd_msg_wait); | |
48 | static atomic_t prd_usage; | |
49 | ||
50 | static bool opal_prd_range_is_valid(uint64_t addr, uint64_t size) | |
51 | { | |
52 | struct device_node *parent, *node; | |
53 | bool found; | |
54 | ||
55 | if (addr + size < addr) | |
56 | return false; | |
57 | ||
58 | parent = of_find_node_by_path("/reserved-memory"); | |
59 | if (!parent) | |
60 | return false; | |
61 | ||
62 | found = false; | |
63 | ||
64 | for_each_child_of_node(parent, node) { | |
65 | uint64_t range_addr, range_size, range_end; | |
66 | const __be32 *addrp; | |
67 | const char *label; | |
68 | ||
69 | addrp = of_get_address(node, 0, &range_size, NULL); | |
70 | ||
71 | range_addr = of_read_number(addrp, 2); | |
72 | range_end = range_addr + range_size; | |
73 | ||
74 | label = of_get_property(node, "ibm,prd-label", NULL); | |
75 | ||
76 | /* PRD ranges need a label */ | |
77 | if (!label) | |
78 | continue; | |
79 | ||
80 | if (range_end <= range_addr) | |
81 | continue; | |
82 | ||
83 | if (addr >= range_addr && addr + size <= range_end) { | |
84 | found = true; | |
85 | of_node_put(node); | |
86 | break; | |
87 | } | |
88 | } | |
89 | ||
90 | of_node_put(parent); | |
91 | return found; | |
92 | } | |
93 | ||
94 | static int opal_prd_open(struct inode *inode, struct file *file) | |
95 | { | |
96 | /* | |
97 | * Prevent multiple (separate) processes from concurrent interactions | |
98 | * with the FW PRD channel | |
99 | */ | |
100 | if (atomic_xchg(&prd_usage, 1) == 1) | |
101 | return -EBUSY; | |
102 | ||
103 | return 0; | |
104 | } | |
105 | ||
106 | /* | |
107 | * opal_prd_mmap - maps firmware-provided ranges into userspace | |
108 | * @file: file structure for the device | |
109 | * @vma: VMA to map the registers into | |
110 | */ | |
111 | ||
112 | static int opal_prd_mmap(struct file *file, struct vm_area_struct *vma) | |
113 | { | |
114 | size_t addr, size; | |
d8ea782b | 115 | pgprot_t page_prot; |
0d7cd855 JK |
116 | int rc; |
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 | ||
d8ea782b VS |
129 | page_prot = phys_mem_access_prot(file, vma->vm_pgoff, |
130 | size, vma->vm_page_prot); | |
0d7cd855 JK |
131 | |
132 | rc = remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff, size, | |
d8ea782b | 133 | page_prot); |
0d7cd855 JK |
134 | |
135 | return rc; | |
136 | } | |
137 | ||
138 | static bool opal_msg_queue_empty(void) | |
139 | { | |
140 | unsigned long flags; | |
141 | bool ret; | |
142 | ||
143 | spin_lock_irqsave(&opal_prd_msg_queue_lock, flags); | |
144 | ret = list_empty(&opal_prd_msg_queue); | |
145 | spin_unlock_irqrestore(&opal_prd_msg_queue_lock, flags); | |
146 | ||
147 | return ret; | |
148 | } | |
149 | ||
150 | static unsigned int opal_prd_poll(struct file *file, | |
151 | struct poll_table_struct *wait) | |
152 | { | |
153 | poll_wait(file, &opal_prd_msg_wait, wait); | |
154 | ||
155 | if (!opal_msg_queue_empty()) | |
156 | return POLLIN | POLLRDNORM; | |
157 | ||
158 | return 0; | |
159 | } | |
160 | ||
161 | static ssize_t opal_prd_read(struct file *file, char __user *buf, | |
162 | size_t count, loff_t *ppos) | |
163 | { | |
164 | struct opal_prd_msg_queue_item *item; | |
165 | unsigned long flags; | |
166 | ssize_t size, err; | |
167 | int rc; | |
168 | ||
169 | /* we need at least a header's worth of data */ | |
170 | if (count < sizeof(item->msg)) | |
171 | return -EINVAL; | |
172 | ||
173 | if (*ppos) | |
174 | return -ESPIPE; | |
175 | ||
176 | item = NULL; | |
177 | ||
178 | for (;;) { | |
179 | ||
180 | spin_lock_irqsave(&opal_prd_msg_queue_lock, flags); | |
181 | if (!list_empty(&opal_prd_msg_queue)) { | |
182 | item = list_first_entry(&opal_prd_msg_queue, | |
183 | struct opal_prd_msg_queue_item, list); | |
184 | list_del(&item->list); | |
185 | } | |
186 | spin_unlock_irqrestore(&opal_prd_msg_queue_lock, flags); | |
187 | ||
188 | if (item) | |
189 | break; | |
190 | ||
191 | if (file->f_flags & O_NONBLOCK) | |
192 | return -EAGAIN; | |
193 | ||
194 | rc = wait_event_interruptible(opal_prd_msg_wait, | |
195 | !opal_msg_queue_empty()); | |
196 | if (rc) | |
197 | return -EINTR; | |
198 | } | |
199 | ||
200 | size = be16_to_cpu(item->msg.size); | |
201 | if (size > count) { | |
202 | err = -EINVAL; | |
203 | goto err_requeue; | |
204 | } | |
205 | ||
206 | rc = copy_to_user(buf, &item->msg, size); | |
207 | if (rc) { | |
208 | err = -EFAULT; | |
209 | goto err_requeue; | |
210 | } | |
211 | ||
212 | kfree(item); | |
213 | ||
214 | return size; | |
215 | ||
216 | err_requeue: | |
217 | /* eep! re-queue at the head of the list */ | |
218 | spin_lock_irqsave(&opal_prd_msg_queue_lock, flags); | |
219 | list_add(&item->list, &opal_prd_msg_queue); | |
220 | spin_unlock_irqrestore(&opal_prd_msg_queue_lock, flags); | |
221 | return err; | |
222 | } | |
223 | ||
224 | static ssize_t opal_prd_write(struct file *file, const char __user *buf, | |
225 | size_t count, loff_t *ppos) | |
226 | { | |
227 | struct opal_prd_msg_header hdr; | |
228 | ssize_t size; | |
229 | void *msg; | |
230 | int rc; | |
231 | ||
232 | size = sizeof(hdr); | |
233 | ||
234 | if (count < size) | |
235 | return -EINVAL; | |
236 | ||
237 | /* grab the header */ | |
238 | rc = copy_from_user(&hdr, buf, sizeof(hdr)); | |
239 | if (rc) | |
240 | return -EFAULT; | |
241 | ||
242 | size = be16_to_cpu(hdr.size); | |
243 | ||
244 | msg = kmalloc(size, GFP_KERNEL); | |
245 | if (!msg) | |
246 | return -ENOMEM; | |
247 | ||
248 | rc = copy_from_user(msg, buf, size); | |
249 | if (rc) { | |
250 | size = -EFAULT; | |
251 | goto out_free; | |
252 | } | |
253 | ||
254 | rc = opal_prd_msg(msg); | |
255 | if (rc) { | |
256 | pr_warn("write: opal_prd_msg returned %d\n", rc); | |
257 | size = -EIO; | |
258 | } | |
259 | ||
260 | out_free: | |
261 | kfree(msg); | |
262 | ||
263 | return size; | |
264 | } | |
265 | ||
266 | static int opal_prd_release(struct inode *inode, struct file *file) | |
267 | { | |
268 | struct opal_prd_msg_header msg; | |
269 | ||
270 | msg.size = cpu_to_be16(sizeof(msg)); | |
271 | msg.type = OPAL_PRD_MSG_TYPE_FINI; | |
272 | ||
273 | opal_prd_msg((struct opal_prd_msg *)&msg); | |
274 | ||
275 | atomic_xchg(&prd_usage, 0); | |
276 | ||
277 | return 0; | |
278 | } | |
279 | ||
280 | static long opal_prd_ioctl(struct file *file, unsigned int cmd, | |
281 | unsigned long param) | |
282 | { | |
283 | struct opal_prd_info info; | |
284 | struct opal_prd_scom scom; | |
285 | int rc = 0; | |
286 | ||
287 | switch (cmd) { | |
288 | case OPAL_PRD_GET_INFO: | |
289 | memset(&info, 0, sizeof(info)); | |
290 | info.version = OPAL_PRD_KERNEL_VERSION; | |
291 | rc = copy_to_user((void __user *)param, &info, sizeof(info)); | |
292 | if (rc) | |
293 | return -EFAULT; | |
294 | break; | |
295 | ||
296 | case OPAL_PRD_SCOM_READ: | |
297 | rc = copy_from_user(&scom, (void __user *)param, sizeof(scom)); | |
298 | if (rc) | |
299 | return -EFAULT; | |
300 | ||
301 | scom.rc = opal_xscom_read(scom.chip, scom.addr, | |
302 | (__be64 *)&scom.data); | |
303 | scom.data = be64_to_cpu(scom.data); | |
304 | pr_devel("ioctl SCOM_READ: chip %llx addr %016llx data %016llx rc %lld\n", | |
305 | scom.chip, scom.addr, scom.data, scom.rc); | |
306 | ||
307 | rc = copy_to_user((void __user *)param, &scom, sizeof(scom)); | |
308 | if (rc) | |
309 | return -EFAULT; | |
310 | break; | |
311 | ||
312 | case OPAL_PRD_SCOM_WRITE: | |
313 | rc = copy_from_user(&scom, (void __user *)param, sizeof(scom)); | |
314 | if (rc) | |
315 | return -EFAULT; | |
316 | ||
317 | scom.rc = opal_xscom_write(scom.chip, scom.addr, scom.data); | |
318 | pr_devel("ioctl SCOM_WRITE: chip %llx addr %016llx data %016llx rc %lld\n", | |
319 | scom.chip, scom.addr, scom.data, scom.rc); | |
320 | ||
321 | rc = copy_to_user((void __user *)param, &scom, sizeof(scom)); | |
322 | if (rc) | |
323 | return -EFAULT; | |
324 | break; | |
325 | ||
326 | default: | |
327 | rc = -EINVAL; | |
328 | } | |
329 | ||
330 | return rc; | |
331 | } | |
332 | ||
333 | static const struct file_operations opal_prd_fops = { | |
334 | .open = opal_prd_open, | |
335 | .mmap = opal_prd_mmap, | |
336 | .poll = opal_prd_poll, | |
337 | .read = opal_prd_read, | |
338 | .write = opal_prd_write, | |
339 | .unlocked_ioctl = opal_prd_ioctl, | |
340 | .release = opal_prd_release, | |
341 | .owner = THIS_MODULE, | |
342 | }; | |
343 | ||
344 | static struct miscdevice opal_prd_dev = { | |
345 | .minor = MISC_DYNAMIC_MINOR, | |
346 | .name = "opal-prd", | |
347 | .fops = &opal_prd_fops, | |
348 | }; | |
349 | ||
350 | /* opal interface */ | |
351 | static int opal_prd_msg_notifier(struct notifier_block *nb, | |
352 | unsigned long msg_type, void *_msg) | |
353 | { | |
354 | struct opal_prd_msg_queue_item *item; | |
355 | struct opal_prd_msg_header *hdr; | |
356 | struct opal_msg *msg = _msg; | |
7185795a | 357 | int msg_size, item_size; |
0d7cd855 | 358 | unsigned long flags; |
0d7cd855 JK |
359 | |
360 | if (msg_type != OPAL_MSG_PRD) | |
361 | return 0; | |
362 | ||
7185795a JK |
363 | /* Calculate total size of the message and item we need to store. The |
364 | * 'size' field in the header includes the header itself. */ | |
0d7cd855 | 365 | hdr = (void *)msg->params; |
7185795a JK |
366 | msg_size = be16_to_cpu(hdr->size); |
367 | item_size = msg_size + sizeof(*item) - sizeof(item->msg); | |
0d7cd855 | 368 | |
7185795a | 369 | item = kzalloc(item_size, GFP_ATOMIC); |
0d7cd855 JK |
370 | if (!item) |
371 | return -ENOMEM; | |
372 | ||
7185795a | 373 | memcpy(&item->msg, msg->params, msg_size); |
0d7cd855 JK |
374 | |
375 | spin_lock_irqsave(&opal_prd_msg_queue_lock, flags); | |
376 | list_add_tail(&item->list, &opal_prd_msg_queue); | |
377 | spin_unlock_irqrestore(&opal_prd_msg_queue_lock, flags); | |
378 | ||
379 | wake_up_interruptible(&opal_prd_msg_wait); | |
380 | ||
381 | return 0; | |
382 | } | |
383 | ||
384 | static struct notifier_block opal_prd_event_nb = { | |
385 | .notifier_call = opal_prd_msg_notifier, | |
386 | .next = NULL, | |
387 | .priority = 0, | |
388 | }; | |
389 | ||
390 | static int opal_prd_probe(struct platform_device *pdev) | |
391 | { | |
392 | int rc; | |
393 | ||
394 | if (!pdev || !pdev->dev.of_node) | |
395 | return -ENODEV; | |
396 | ||
397 | /* We should only have one prd driver instance per machine; ensure | |
398 | * that we only get a valid probe on a single OF node. | |
399 | */ | |
400 | if (prd_node) | |
401 | return -EBUSY; | |
402 | ||
403 | prd_node = pdev->dev.of_node; | |
404 | ||
405 | rc = opal_message_notifier_register(OPAL_MSG_PRD, &opal_prd_event_nb); | |
406 | if (rc) { | |
407 | pr_err("Couldn't register event notifier\n"); | |
408 | return rc; | |
409 | } | |
410 | ||
411 | rc = misc_register(&opal_prd_dev); | |
412 | if (rc) { | |
413 | pr_err("failed to register miscdev\n"); | |
414 | opal_message_notifier_unregister(OPAL_MSG_PRD, | |
415 | &opal_prd_event_nb); | |
416 | return rc; | |
417 | } | |
418 | ||
419 | return 0; | |
420 | } | |
421 | ||
422 | static int opal_prd_remove(struct platform_device *pdev) | |
423 | { | |
424 | misc_deregister(&opal_prd_dev); | |
425 | opal_message_notifier_unregister(OPAL_MSG_PRD, &opal_prd_event_nb); | |
426 | return 0; | |
427 | } | |
428 | ||
429 | static const struct of_device_id opal_prd_match[] = { | |
430 | { .compatible = "ibm,opal-prd" }, | |
431 | { }, | |
432 | }; | |
433 | ||
434 | static struct platform_driver opal_prd_driver = { | |
435 | .driver = { | |
436 | .name = "opal-prd", | |
0d7cd855 JK |
437 | .of_match_table = opal_prd_match, |
438 | }, | |
439 | .probe = opal_prd_probe, | |
440 | .remove = opal_prd_remove, | |
441 | }; | |
442 | ||
443 | module_platform_driver(opal_prd_driver); | |
444 | ||
445 | MODULE_DEVICE_TABLE(of, opal_prd_match); | |
446 | MODULE_DESCRIPTION("PowerNV OPAL runtime diagnostic driver"); | |
447 | MODULE_LICENSE("GPL"); |