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 /* 28 * The msg member must be at the end of the struct, as it's followed by the 29 * message data. 30 */ 31 struct opal_prd_msg_queue_item { 32 struct list_head list; 33 struct opal_prd_msg_header msg; 34 }; 35 36 static struct device_node *prd_node; 37 static LIST_HEAD(opal_prd_msg_queue); 38 static DEFINE_SPINLOCK(opal_prd_msg_queue_lock); 39 static DECLARE_WAIT_QUEUE_HEAD(opal_prd_msg_wait); 40 static atomic_t prd_usage; 41 42 static bool opal_prd_range_is_valid(uint64_t addr, uint64_t size) 43 { 44 struct device_node *parent, *node; 45 bool found; 46 47 if (addr + size < addr) 48 return false; 49 50 parent = of_find_node_by_path("/reserved-memory"); 51 if (!parent) 52 return false; 53 54 found = false; 55 56 for_each_child_of_node(parent, node) { 57 uint64_t range_addr, range_size, range_end; 58 const __be32 *addrp; 59 const char *label; 60 61 addrp = of_get_address(node, 0, &range_size, NULL); 62 63 range_addr = of_read_number(addrp, 2); 64 range_end = range_addr + range_size; 65 66 label = of_get_property(node, "ibm,prd-label", NULL); 67 68 /* PRD ranges need a label */ 69 if (!label) 70 continue; 71 72 if (range_end <= range_addr) 73 continue; 74 75 if (addr >= range_addr && addr + size <= range_end) { 76 found = true; 77 of_node_put(node); 78 break; 79 } 80 } 81 82 of_node_put(parent); 83 return found; 84 } 85 86 static int opal_prd_open(struct inode *inode, struct file *file) 87 { 88 /* 89 * Prevent multiple (separate) processes from concurrent interactions 90 * with the FW PRD channel 91 */ 92 if (atomic_xchg(&prd_usage, 1) == 1) 93 return -EBUSY; 94 95 return 0; 96 } 97 98 /* 99 * opal_prd_mmap - maps firmware-provided ranges into userspace 100 * @file: file structure for the device 101 * @vma: VMA to map the registers into 102 */ 103 104 static int opal_prd_mmap(struct file *file, struct vm_area_struct *vma) 105 { 106 size_t addr, size; 107 pgprot_t page_prot; 108 109 pr_devel("opal_prd_mmap(0x%016lx, 0x%016lx, 0x%lx, 0x%lx)\n", 110 vma->vm_start, vma->vm_end, vma->vm_pgoff, 111 vma->vm_flags); 112 113 addr = vma->vm_pgoff << PAGE_SHIFT; 114 size = vma->vm_end - vma->vm_start; 115 116 /* ensure we're mapping within one of the allowable ranges */ 117 if (!opal_prd_range_is_valid(addr, size)) 118 return -EINVAL; 119 120 page_prot = phys_mem_access_prot(file, vma->vm_pgoff, 121 size, vma->vm_page_prot); 122 123 return remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff, size, 124 page_prot); 125 } 126 127 static bool opal_msg_queue_empty(void) 128 { 129 unsigned long flags; 130 bool ret; 131 132 spin_lock_irqsave(&opal_prd_msg_queue_lock, flags); 133 ret = list_empty(&opal_prd_msg_queue); 134 spin_unlock_irqrestore(&opal_prd_msg_queue_lock, flags); 135 136 return ret; 137 } 138 139 static __poll_t opal_prd_poll(struct file *file, 140 struct poll_table_struct *wait) 141 { 142 poll_wait(file, &opal_prd_msg_wait, wait); 143 144 if (!opal_msg_queue_empty()) 145 return EPOLLIN | EPOLLRDNORM; 146 147 return 0; 148 } 149 150 static ssize_t opal_prd_read(struct file *file, char __user *buf, 151 size_t count, loff_t *ppos) 152 { 153 struct opal_prd_msg_queue_item *item; 154 unsigned long flags; 155 ssize_t size, err; 156 int rc; 157 158 /* we need at least a header's worth of data */ 159 if (count < sizeof(item->msg)) 160 return -EINVAL; 161 162 if (*ppos) 163 return -ESPIPE; 164 165 item = NULL; 166 167 for (;;) { 168 169 spin_lock_irqsave(&opal_prd_msg_queue_lock, flags); 170 if (!list_empty(&opal_prd_msg_queue)) { 171 item = list_first_entry(&opal_prd_msg_queue, 172 struct opal_prd_msg_queue_item, list); 173 list_del(&item->list); 174 } 175 spin_unlock_irqrestore(&opal_prd_msg_queue_lock, flags); 176 177 if (item) 178 break; 179 180 if (file->f_flags & O_NONBLOCK) 181 return -EAGAIN; 182 183 rc = wait_event_interruptible(opal_prd_msg_wait, 184 !opal_msg_queue_empty()); 185 if (rc) 186 return -EINTR; 187 } 188 189 size = be16_to_cpu(item->msg.size); 190 if (size > count) { 191 err = -EINVAL; 192 goto err_requeue; 193 } 194 195 rc = copy_to_user(buf, &item->msg, size); 196 if (rc) { 197 err = -EFAULT; 198 goto err_requeue; 199 } 200 201 kfree(item); 202 203 return size; 204 205 err_requeue: 206 /* eep! re-queue at the head of the list */ 207 spin_lock_irqsave(&opal_prd_msg_queue_lock, flags); 208 list_add(&item->list, &opal_prd_msg_queue); 209 spin_unlock_irqrestore(&opal_prd_msg_queue_lock, flags); 210 return err; 211 } 212 213 static ssize_t opal_prd_write(struct file *file, const char __user *buf, 214 size_t count, loff_t *ppos) 215 { 216 struct opal_prd_msg_header hdr; 217 ssize_t size; 218 void *msg; 219 int rc; 220 221 size = sizeof(hdr); 222 223 if (count < size) 224 return -EINVAL; 225 226 /* grab the header */ 227 rc = copy_from_user(&hdr, buf, sizeof(hdr)); 228 if (rc) 229 return -EFAULT; 230 231 size = be16_to_cpu(hdr.size); 232 233 msg = memdup_user(buf, size); 234 if (IS_ERR(msg)) 235 return PTR_ERR(msg); 236 237 rc = opal_prd_msg(msg); 238 if (rc) { 239 pr_warn("write: opal_prd_msg returned %d\n", rc); 240 size = -EIO; 241 } 242 243 kfree(msg); 244 245 return size; 246 } 247 248 static int opal_prd_release(struct inode *inode, struct file *file) 249 { 250 struct opal_prd_msg_header msg; 251 252 msg.size = cpu_to_be16(sizeof(msg)); 253 msg.type = OPAL_PRD_MSG_TYPE_FINI; 254 255 opal_prd_msg((struct opal_prd_msg *)&msg); 256 257 atomic_xchg(&prd_usage, 0); 258 259 return 0; 260 } 261 262 static long opal_prd_ioctl(struct file *file, unsigned int cmd, 263 unsigned long param) 264 { 265 struct opal_prd_info info; 266 struct opal_prd_scom scom; 267 int rc = 0; 268 269 switch (cmd) { 270 case OPAL_PRD_GET_INFO: 271 memset(&info, 0, sizeof(info)); 272 info.version = OPAL_PRD_KERNEL_VERSION; 273 rc = copy_to_user((void __user *)param, &info, sizeof(info)); 274 if (rc) 275 return -EFAULT; 276 break; 277 278 case OPAL_PRD_SCOM_READ: 279 rc = copy_from_user(&scom, (void __user *)param, sizeof(scom)); 280 if (rc) 281 return -EFAULT; 282 283 scom.rc = opal_xscom_read(scom.chip, scom.addr, 284 (__be64 *)&scom.data); 285 scom.data = be64_to_cpu(scom.data); 286 pr_devel("ioctl SCOM_READ: chip %llx addr %016llx data %016llx rc %lld\n", 287 scom.chip, scom.addr, scom.data, scom.rc); 288 289 rc = copy_to_user((void __user *)param, &scom, sizeof(scom)); 290 if (rc) 291 return -EFAULT; 292 break; 293 294 case OPAL_PRD_SCOM_WRITE: 295 rc = copy_from_user(&scom, (void __user *)param, sizeof(scom)); 296 if (rc) 297 return -EFAULT; 298 299 scom.rc = opal_xscom_write(scom.chip, scom.addr, scom.data); 300 pr_devel("ioctl SCOM_WRITE: chip %llx addr %016llx data %016llx rc %lld\n", 301 scom.chip, scom.addr, scom.data, scom.rc); 302 303 rc = copy_to_user((void __user *)param, &scom, sizeof(scom)); 304 if (rc) 305 return -EFAULT; 306 break; 307 308 default: 309 rc = -EINVAL; 310 } 311 312 return rc; 313 } 314 315 static const struct file_operations opal_prd_fops = { 316 .open = opal_prd_open, 317 .mmap = opal_prd_mmap, 318 .poll = opal_prd_poll, 319 .read = opal_prd_read, 320 .write = opal_prd_write, 321 .unlocked_ioctl = opal_prd_ioctl, 322 .release = opal_prd_release, 323 .owner = THIS_MODULE, 324 }; 325 326 static struct miscdevice opal_prd_dev = { 327 .minor = MISC_DYNAMIC_MINOR, 328 .name = "opal-prd", 329 .fops = &opal_prd_fops, 330 }; 331 332 /* opal interface */ 333 static int opal_prd_msg_notifier(struct notifier_block *nb, 334 unsigned long msg_type, void *_msg) 335 { 336 struct opal_prd_msg_queue_item *item; 337 struct opal_prd_msg_header *hdr; 338 struct opal_msg *msg = _msg; 339 int msg_size, item_size; 340 unsigned long flags; 341 342 if (msg_type != OPAL_MSG_PRD && msg_type != OPAL_MSG_PRD2) 343 return 0; 344 345 /* Calculate total size of the message and item we need to store. The 346 * 'size' field in the header includes the header itself. */ 347 hdr = (void *)msg->params; 348 msg_size = be16_to_cpu(hdr->size); 349 item_size = msg_size + sizeof(*item) - sizeof(item->msg); 350 351 item = kzalloc(item_size, GFP_ATOMIC); 352 if (!item) 353 return -ENOMEM; 354 355 memcpy(&item->msg, msg->params, msg_size); 356 357 spin_lock_irqsave(&opal_prd_msg_queue_lock, flags); 358 list_add_tail(&item->list, &opal_prd_msg_queue); 359 spin_unlock_irqrestore(&opal_prd_msg_queue_lock, flags); 360 361 wake_up_interruptible(&opal_prd_msg_wait); 362 363 return 0; 364 } 365 366 static struct notifier_block opal_prd_event_nb = { 367 .notifier_call = opal_prd_msg_notifier, 368 .next = NULL, 369 .priority = 0, 370 }; 371 372 static struct notifier_block opal_prd_event_nb2 = { 373 .notifier_call = opal_prd_msg_notifier, 374 .next = NULL, 375 .priority = 0, 376 }; 377 378 static int opal_prd_probe(struct platform_device *pdev) 379 { 380 int rc; 381 382 if (!pdev || !pdev->dev.of_node) 383 return -ENODEV; 384 385 /* We should only have one prd driver instance per machine; ensure 386 * that we only get a valid probe on a single OF node. 387 */ 388 if (prd_node) 389 return -EBUSY; 390 391 prd_node = pdev->dev.of_node; 392 393 rc = opal_message_notifier_register(OPAL_MSG_PRD, &opal_prd_event_nb); 394 if (rc) { 395 pr_err("Couldn't register event notifier\n"); 396 return rc; 397 } 398 399 rc = opal_message_notifier_register(OPAL_MSG_PRD2, &opal_prd_event_nb2); 400 if (rc) { 401 pr_err("Couldn't register PRD2 event notifier\n"); 402 opal_message_notifier_unregister(OPAL_MSG_PRD, &opal_prd_event_nb); 403 return rc; 404 } 405 406 rc = misc_register(&opal_prd_dev); 407 if (rc) { 408 pr_err("failed to register miscdev\n"); 409 opal_message_notifier_unregister(OPAL_MSG_PRD, 410 &opal_prd_event_nb); 411 opal_message_notifier_unregister(OPAL_MSG_PRD2, 412 &opal_prd_event_nb2); 413 return rc; 414 } 415 416 return 0; 417 } 418 419 static int opal_prd_remove(struct platform_device *pdev) 420 { 421 misc_deregister(&opal_prd_dev); 422 opal_message_notifier_unregister(OPAL_MSG_PRD, &opal_prd_event_nb); 423 opal_message_notifier_unregister(OPAL_MSG_PRD2, &opal_prd_event_nb2); 424 return 0; 425 } 426 427 static const struct of_device_id opal_prd_match[] = { 428 { .compatible = "ibm,opal-prd" }, 429 { }, 430 }; 431 432 static struct platform_driver opal_prd_driver = { 433 .driver = { 434 .name = "opal-prd", 435 .of_match_table = opal_prd_match, 436 }, 437 .probe = opal_prd_probe, 438 .remove = opal_prd_remove, 439 }; 440 441 module_platform_driver(opal_prd_driver); 442 443 MODULE_DEVICE_TABLE(of, opal_prd_match); 444 MODULE_DESCRIPTION("PowerNV OPAL runtime diagnostic driver"); 445 MODULE_LICENSE("GPL"); 446