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 /*
  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 int opal_prd_probe(struct platform_device *pdev)
 373 {
 374         int rc;
 375
 376         if (!pdev || !pdev->dev.of_node)
 377                 return -ENODEV;
 378
 379         /* We should only have one prd driver instance per machine; ensure
 380          * that we only get a valid probe on a single OF node.
 381          */
 382         if (prd_node)
 383                 return -EBUSY;
 384
 385         prd_node = pdev->dev.of_node;
 386
 387         rc = opal_message_notifier_register(OPAL_MSG_PRD, &opal_prd_event_nb);
 388         if (rc) {
 389                 pr_err("Couldn't register event notifier\n");
 390                 return rc;
 391         }
 392
 393         rc = opal_message_notifier_register(OPAL_MSG_PRD2, &opal_prd_event_nb);
 394         if (rc) {
 395                 pr_err("Couldn't register PRD2 event notifier\n");
 396                 return rc;
 397         }
 398
 399         rc = misc_register(&opal_prd_dev);
 400         if (rc) {
 401                 pr_err("failed to register miscdev\n");
 402                 opal_message_notifier_unregister(OPAL_MSG_PRD,
 403                                 &opal_prd_event_nb);
 404                 return rc;
 405         }
 406
 407         return 0;
 408 }
 409
 410 static int opal_prd_remove(struct platform_device *pdev)
 411 {
 412         misc_deregister(&opal_prd_dev);
 413         opal_message_notifier_unregister(OPAL_MSG_PRD, &opal_prd_event_nb);
 414         return 0;
 415 }
 416
 417 static const struct of_device_id opal_prd_match[] = {
 418         { .compatible = "ibm,opal-prd" },
 419         { },
 420 };
 421
 422 static struct platform_driver opal_prd_driver = {
 423         .driver = {
 424                 .name           = "opal-prd",
 425                 .of_match_table = opal_prd_match,
 426         },
 427         .probe  = opal_prd_probe,
 428         .remove = opal_prd_remove,
 429 };
 430
 431 module_platform_driver(opal_prd_driver);
 432
 433 MODULE_DEVICE_TABLE(of, opal_prd_match);
 434 MODULE_DESCRIPTION("PowerNV OPAL runtime diagnostic driver");
 435 MODULE_LICENSE("GPL");