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

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