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