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 int 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 return 0; 434 } 435 436 static const struct of_device_id opal_prd_match[] = { 437 { .compatible = "ibm,opal-prd" }, 438 { }, 439 }; 440 441 static struct platform_driver opal_prd_driver = { 442 .driver = { 443 .name = "opal-prd", 444 .of_match_table = opal_prd_match, 445 }, 446 .probe = opal_prd_probe, 447 .remove = opal_prd_remove, 448 }; 449 450 module_platform_driver(opal_prd_driver); 451 452 MODULE_DEVICE_TABLE(of, opal_prd_match); 453 MODULE_DESCRIPTION("PowerNV OPAL runtime diagnostic driver"); 454 MODULE_LICENSE("GPL"); 455