arch/powerpc/platforms/powernv/opal-prd.c

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