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   1 /*
   2  * dell_rbu.c
   3  * Bios Update driver for Dell systems
   4  * Author: Dell Inc
   5  *         Abhay Salunke <abhay_salunke@dell.com>
   6  *
   7  * Copyright (C) 2005 Dell Inc.
   8  *
   9  * Remote BIOS Update (rbu) driver is used for updating DELL BIOS by
  10  * creating entries in the /sys file systems on Linux 2.6 and higher
  11  * kernels. The driver supports two mechanism to update the BIOS namely
  12  * contiguous and packetized. Both these methods still require having some
  13  * application to set the CMOS bit indicating the BIOS to update itself
  14  * after a reboot.
  15  *
  16  * Contiguous method:
  17  * This driver writes the incoming data in a monolithic image by allocating
  18  * contiguous physical pages large enough to accommodate the incoming BIOS
  19  * image size.
  20  *
  21  * Packetized method:
  22  * The driver writes the incoming packet image by allocating a new packet
  23  * on every time the packet data is written. This driver requires an
  24  * application to break the BIOS image in to fixed sized packet chunks.
  25  *
  26  * See Documentation/dell_rbu.txt for more info.
  27  *
  28  * This program is free software; you can redistribute it and/or modify
  29  * it under the terms of the GNU General Public License v2.0 as published by
  30  * the Free Software Foundation
  31  *
  32  * This program is distributed in the hope that it will be useful,
  33  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  34  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  35  * GNU General Public License for more details.
  36  */
  37 #include <linux/version.h>
  38 #include <linux/config.h>
  39 #include <linux/init.h>
  40 #include <linux/module.h>
  41 #include <linux/string.h>
  42 #include <linux/errno.h>
  43 #include <linux/blkdev.h>
  44 #include <linux/device.h>
  45 #include <linux/spinlock.h>
  46 #include <linux/moduleparam.h>
  47 #include <linux/firmware.h>
  48 #include <linux/dma-mapping.h>
  49
  50 MODULE_AUTHOR("Abhay Salunke <abhay_salunke@dell.com>");
  51 MODULE_DESCRIPTION("Driver for updating BIOS image on DELL systems");
  52 MODULE_LICENSE("GPL");
  53 MODULE_VERSION("2.0");
  54
  55 #define BIOS_SCAN_LIMIT 0xffffffff
  56 #define MAX_IMAGE_LENGTH 16
  57 static struct _rbu_data {
  58         void *image_update_buffer;
  59         unsigned long image_update_buffer_size;
  60         unsigned long bios_image_size;
  61         int image_update_ordernum;
  62         int dma_alloc;
  63         spinlock_t lock;
  64         unsigned long packet_read_count;
  65         unsigned long packet_write_count;
  66         unsigned long num_packets;
  67         unsigned long packetsize;
  68         int entry_created;
  69 } rbu_data;
  70
  71 static char image_type[MAX_IMAGE_LENGTH + 1] = "mono";
  72 module_param_string(image_type, image_type, sizeof (image_type), 0);
  73 MODULE_PARM_DESC(image_type, "BIOS image type. choose- mono or packet");
  74
  75 struct packet_data {
  76         struct list_head list;
  77         size_t length;
  78         void *data;
  79         int ordernum;
  80 };
  81
  82 static struct packet_data packet_data_head;
  83
  84 static struct platform_device *rbu_device;
  85 static int context;
  86 static dma_addr_t dell_rbu_dmaaddr;
  87
  88 static void init_packet_head(void)
  89 {
  90         INIT_LIST_HEAD(&packet_data_head.list);
  91         rbu_data.packet_write_count = 0;
  92         rbu_data.packet_read_count = 0;
  93         rbu_data.num_packets = 0;
  94         rbu_data.packetsize = 0;
  95 }
  96
  97 static int fill_last_packet(void *data, size_t length)
  98 {
  99         struct list_head *ptemp_list;
 100         struct packet_data *packet = NULL;
 101         int packet_count = 0;
 102
 103         pr_debug("fill_last_packet: entry \n");
 104
 105         if (!rbu_data.num_packets) {
 106                 pr_debug("fill_last_packet: num_packets=0\n");
 107                 return -ENOMEM;
 108         }
 109
 110         packet_count = rbu_data.num_packets;
 111
 112         ptemp_list = (&packet_data_head.list)->prev;
 113
 114         packet = list_entry(ptemp_list, struct packet_data, list);
 115
 116         if ((rbu_data.packet_write_count + length) > rbu_data.packetsize) {
 117                 pr_debug("dell_rbu:%s: packet size data "
 118                         "overrun\n", __FUNCTION__);
 119                 return -EINVAL;
 120         }
 121
 122         pr_debug("fill_last_packet : buffer = %p\n", packet->data);
 123
 124         memcpy((packet->data + rbu_data.packet_write_count), data, length);
 125
 126         if ((rbu_data.packet_write_count + length) == rbu_data.packetsize) {
 127                 /*
 128                  * this was the last data chunk in the packet
 129                  * so reinitialize the packet data counter to zero
 130                  */
 131                 rbu_data.packet_write_count = 0;
 132         } else
 133                 rbu_data.packet_write_count += length;
 134
 135         pr_debug("fill_last_packet: exit \n");
 136         return 0;
 137 }
 138
 139 static int create_packet(size_t length)
 140 {
 141         struct packet_data *newpacket;
 142         int ordernum = 0;
 143
 144         pr_debug("create_packet: entry \n");
 145
 146         if (!rbu_data.packetsize) {
 147                 pr_debug("create_packet: packetsize not specified\n");
 148                 return -EINVAL;
 149         }
 150         spin_unlock(&rbu_data.lock);
 151         newpacket = kmalloc(sizeof (struct packet_data), GFP_KERNEL);
 152         spin_lock(&rbu_data.lock);
 153
 154         if (!newpacket) {
 155                 printk(KERN_WARNING
 156                         "dell_rbu:%s: failed to allocate new "
 157                         "packet\n", __FUNCTION__);
 158                 return -ENOMEM;
 159         }
 160
 161         ordernum = get_order(length);
 162         /*
 163          * there is no upper limit on memory
 164          * address for packetized mechanism
 165          */
 166         spin_unlock(&rbu_data.lock);
 167         newpacket->data = (unsigned char *) __get_free_pages(GFP_KERNEL,
 168                 ordernum);
 169         spin_lock(&rbu_data.lock);
 170
 171         pr_debug("create_packet: newpacket %p\n", newpacket->data);
 172
 173         if (!newpacket->data) {
 174                 printk(KERN_WARNING
 175                         "dell_rbu:%s: failed to allocate new "
 176                         "packet\n", __FUNCTION__);
 177                 kfree(newpacket);
 178                 return -ENOMEM;
 179         }
 180
 181         newpacket->ordernum = ordernum;
 182         ++rbu_data.num_packets;
 183         /*
 184          * initialize the newly created packet headers
 185          */
 186         INIT_LIST_HEAD(&newpacket->list);
 187         list_add_tail(&newpacket->list, &packet_data_head.list);
 188         /*
 189          * packets have fixed size
 190          */
 191         newpacket->length = rbu_data.packetsize;
 192
 193         pr_debug("create_packet: exit \n");
 194
 195         return 0;
 196 }
 197
 198 static int packetize_data(void *data, size_t length)
 199 {
 200         int rc = 0;
 201
 202         if (!rbu_data.packet_write_count) {
 203                 if ((rc = create_packet(length)))
 204                         return rc;
 205         }
 206         if ((rc = fill_last_packet(data, length)))
 207                 return rc;
 208
 209         return rc;
 210 }
 211
 212 static int do_packet_read(char *data, struct list_head *ptemp_list,
 213         int length, int bytes_read, int *list_read_count)
 214 {
 215         void *ptemp_buf;
 216         struct packet_data *newpacket = NULL;
 217         int bytes_copied = 0;
 218         int j = 0;
 219
 220         newpacket = list_entry(ptemp_list, struct packet_data, list);
 221         *list_read_count += newpacket->length;
 222
 223         if (*list_read_count > bytes_read) {
 224                 /* point to the start of unread data */
 225                 j = newpacket->length - (*list_read_count - bytes_read);
 226                 /* point to the offset in the packet buffer */
 227                 ptemp_buf = (u8 *) newpacket->data + j;
 228                 /*
 229                  * check if there is enough room in
 230                  * * the incoming buffer
 231                  */
 232                 if (length > (*list_read_count - bytes_read))
 233                         /*
 234                          * copy what ever is there in this
 235                          * packet and move on
 236                          */
 237                         bytes_copied = (*list_read_count - bytes_read);
 238                 else
 239                         /* copy the remaining */
 240                         bytes_copied = length;
 241                 memcpy(data, ptemp_buf, bytes_copied);
 242         }
 243         return bytes_copied;
 244 }
 245
 246 static int packet_read_list(char *data, size_t *pread_length)
 247 {
 248         struct list_head *ptemp_list;
 249         int temp_count = 0;
 250         int bytes_copied = 0;
 251         int bytes_read = 0;
 252         int remaining_bytes = 0;
 253         char *pdest = data;
 254
 255         /* check if we have any packets */
 256         if (0 == rbu_data.num_packets)
 257                 return -ENOMEM;
 258
 259         remaining_bytes = *pread_length;
 260         bytes_read = rbu_data.packet_read_count;
 261
 262         ptemp_list = (&packet_data_head.list)->next;
 263         while (!list_empty(ptemp_list)) {
 264                 bytes_copied = do_packet_read(pdest, ptemp_list,
 265                         remaining_bytes, bytes_read, &temp_count);
 266                 remaining_bytes -= bytes_copied;
 267                 bytes_read += bytes_copied;
 268                 pdest += bytes_copied;
 269                 /*
 270                  * check if we reached end of buffer before reaching the
 271                  * last packet
 272                  */
 273                 if (remaining_bytes == 0)
 274                         break;
 275
 276                 ptemp_list = ptemp_list->next;
 277         }
 278         /*finally set the bytes read */
 279         *pread_length = bytes_read - rbu_data.packet_read_count;
 280         rbu_data.packet_read_count = bytes_read;
 281         return 0;
 282 }
 283
 284 static void packet_empty_list(void)
 285 {
 286         struct list_head *ptemp_list;
 287         struct list_head *pnext_list;
 288         struct packet_data *newpacket;
 289
 290         ptemp_list = (&packet_data_head.list)->next;
 291         while (!list_empty(ptemp_list)) {
 292                 newpacket =
 293                         list_entry(ptemp_list, struct packet_data, list);
 294                 pnext_list = ptemp_list->next;
 295                 list_del(ptemp_list);
 296                 ptemp_list = pnext_list;
 297                 /*
 298                  * zero out the RBU packet memory before freeing
 299                  * to make sure there are no stale RBU packets left in memory
 300                  */
 301                 memset(newpacket->data, 0, rbu_data.packetsize);
 302                 free_pages((unsigned long) newpacket->data,
 303                         newpacket->ordernum);
 304                 kfree(newpacket);
 305         }
 306         rbu_data.packet_write_count = 0;
 307         rbu_data.packet_read_count = 0;
 308         rbu_data.num_packets = 0;
 309         rbu_data.packetsize = 0;
 310 }
 311
 312 /*
 313  * img_update_free: Frees the buffer allocated for storing BIOS image
 314  * Always called with lock held and returned with lock held
 315  */
 316 static void img_update_free(void)
 317 {
 318         if (!rbu_data.image_update_buffer)
 319                 return;
 320         /*
 321          * zero out this buffer before freeing it to get rid of any stale
 322          * BIOS image copied in memory.
 323          */
 324         memset(rbu_data.image_update_buffer, 0,
 325                 rbu_data.image_update_buffer_size);
 326         if (rbu_data.dma_alloc == 1)
 327                 dma_free_coherent(NULL, rbu_data.bios_image_size,
 328                         rbu_data.image_update_buffer, dell_rbu_dmaaddr);
 329         else
 330                 free_pages((unsigned long) rbu_data.image_update_buffer,
 331                         rbu_data.image_update_ordernum);
 332
 333         /*
 334          * Re-initialize the rbu_data variables after a free
 335          */
 336         rbu_data.image_update_ordernum = -1;
 337         rbu_data.image_update_buffer = NULL;
 338         rbu_data.image_update_buffer_size = 0;
 339         rbu_data.bios_image_size = 0;
 340         rbu_data.dma_alloc = 0;
 341 }
 342
 343 /*
 344  * img_update_realloc: This function allocates the contiguous pages to
 345  * accommodate the requested size of data. The memory address and size
 346  * values are stored globally and on every call to this function the new
 347  * size is checked to see if more data is required than the existing size.
 348  * If true the previous memory is freed and new allocation is done to
 349  * accommodate the new size. If the incoming size is less then than the
 350  * already allocated size, then that memory is reused. This function is
 351  * called with lock held and returns with lock held.
 352  */
 353 static int img_update_realloc(unsigned long size)
 354 {
 355         unsigned char *image_update_buffer = NULL;
 356         unsigned long rc;
 357         unsigned long img_buf_phys_addr;
 358         int ordernum;
 359         int dma_alloc = 0;
 360
 361         /*
 362          * check if the buffer of sufficient size has been
 363          * already allocated
 364          */
 365         if (rbu_data.image_update_buffer_size >= size) {
 366                 /*
 367                  * check for corruption
 368                  */
 369                 if ((size != 0) && (rbu_data.image_update_buffer == NULL)) {
 370                         printk(KERN_ERR "dell_rbu:%s: corruption "
 371                                 "check failed\n", __FUNCTION__);
 372                         return -EINVAL;
 373                 }
 374                 /*
 375                  * we have a valid pre-allocated buffer with
 376                  * sufficient size
 377                  */
 378                 return 0;
 379         }
 380
 381         /*
 382          * free any previously allocated buffer
 383          */
 384         img_update_free();
 385
 386         spin_unlock(&rbu_data.lock);
 387
 388         ordernum = get_order(size);
 389         image_update_buffer =
 390                 (unsigned char *) __get_free_pages(GFP_KERNEL, ordernum);
 391
 392         img_buf_phys_addr =
 393                 (unsigned long) virt_to_phys(image_update_buffer);
 394
 395         if (img_buf_phys_addr > BIOS_SCAN_LIMIT) {
 396                 free_pages((unsigned long) image_update_buffer, ordernum);
 397                 ordernum = -1;
 398                 image_update_buffer = dma_alloc_coherent(NULL, size,
 399                         &dell_rbu_dmaaddr, GFP_KERNEL);
 400                 dma_alloc = 1;
 401         }
 402
 403         spin_lock(&rbu_data.lock);
 404
 405         if (image_update_buffer != NULL) {
 406                 rbu_data.image_update_buffer = image_update_buffer;
 407                 rbu_data.image_update_buffer_size = size;
 408                 rbu_data.bios_image_size =
 409                         rbu_data.image_update_buffer_size;
 410                 rbu_data.image_update_ordernum = ordernum;
 411                 rbu_data.dma_alloc = dma_alloc;
 412                 rc = 0;
 413         } else {
 414                 pr_debug("Not enough memory for image update:"
 415                         "size = %ld\n", size);
 416                 rc = -ENOMEM;
 417         }
 418
 419         return rc;
 420 }
 421
 422 static ssize_t read_packet_data(char *buffer, loff_t pos, size_t count)
 423 {
 424         int retval;
 425         size_t bytes_left;
 426         size_t data_length;
 427         char *ptempBuf = buffer;
 428         unsigned long imagesize;
 429
 430         /* check to see if we have something to return */
 431         if (rbu_data.num_packets == 0) {
 432                 pr_debug("read_packet_data: no packets written\n");
 433                 retval = -ENOMEM;
 434                 goto read_rbu_data_exit;
 435         }
 436
 437         imagesize = rbu_data.num_packets * rbu_data.packetsize;
 438
 439         if (pos > imagesize) {
 440                 retval = 0;
 441                 printk(KERN_WARNING "dell_rbu:read_packet_data: "
 442                         "data underrun\n");
 443                 goto read_rbu_data_exit;
 444         }
 445
 446         bytes_left = imagesize - pos;
 447         data_length = min(bytes_left, count);
 448
 449         if ((retval = packet_read_list(ptempBuf, &data_length)) < 0)
 450                 goto read_rbu_data_exit;
 451
 452         if ((pos + count) > imagesize) {
 453                 rbu_data.packet_read_count = 0;
 454                 /* this was the last copy */
 455                 retval = bytes_left;
 456         } else
 457                 retval = count;
 458
 459       read_rbu_data_exit:
 460         return retval;
 461 }
 462
 463 static ssize_t read_rbu_mono_data(char *buffer, loff_t pos, size_t count)
 464 {
 465         unsigned char *ptemp = NULL;
 466         size_t bytes_left = 0;
 467         size_t data_length = 0;
 468         ssize_t ret_count = 0;
 469
 470         /* check to see if we have something to return */
 471         if ((rbu_data.image_update_buffer == NULL) ||
 472                 (rbu_data.bios_image_size == 0)) {
 473                 pr_debug("read_rbu_data_mono: image_update_buffer %p ,"
 474                         "bios_image_size %lu\n",
 475                         rbu_data.image_update_buffer,
 476                         rbu_data.bios_image_size);
 477                 ret_count = -ENOMEM;
 478                 goto read_rbu_data_exit;
 479         }
 480
 481         if (pos > rbu_data.bios_image_size) {
 482                 ret_count = 0;
 483                 goto read_rbu_data_exit;
 484         }
 485
 486         bytes_left = rbu_data.bios_image_size - pos;
 487         data_length = min(bytes_left, count);
 488
 489         ptemp = rbu_data.image_update_buffer;
 490         memcpy(buffer, (ptemp + pos), data_length);
 491
 492         if ((pos + count) > rbu_data.bios_image_size)
 493                 /* this was the last copy */
 494                 ret_count = bytes_left;
 495         else
 496                 ret_count = count;
 497       read_rbu_data_exit:
 498         return ret_count;
 499 }
 500
 501 static ssize_t read_rbu_data(struct kobject *kobj, char *buffer,
 502                         loff_t pos, size_t count)
 503 {
 504         ssize_t ret_count = 0;
 505
 506         spin_lock(&rbu_data.lock);
 507
 508         if (!strcmp(image_type, "mono"))
 509                 ret_count = read_rbu_mono_data(buffer, pos, count);
 510         else if (!strcmp(image_type, "packet"))
 511                 ret_count = read_packet_data(buffer, pos, count);
 512         else
 513                 pr_debug("read_rbu_data: invalid image type specified\n");
 514
 515         spin_unlock(&rbu_data.lock);
 516         return ret_count;
 517 }
 518
 519 static void callbackfn_rbu(const struct firmware *fw, void *context)
 520 {
 521         int rc = 0;
 522
 523         if (!fw || !fw->size) {
 524                 rbu_data.entry_created = 0;
 525                 return;
 526         }
 527
 528         spin_lock(&rbu_data.lock);
 529         if (!strcmp(image_type, "mono")) {
 530                 if (!img_update_realloc(fw->size))
 531                         memcpy(rbu_data.image_update_buffer,
 532                                 fw->data, fw->size);
 533         } else if (!strcmp(image_type, "packet")) {
 534                 if (!rbu_data.packetsize)
 535                         rbu_data.packetsize = fw->size;
 536                 else if (rbu_data.packetsize != fw->size) {
 537                         packet_empty_list();
 538                         rbu_data.packetsize = fw->size;
 539                 }
 540                 packetize_data(fw->data, fw->size);
 541         } else
 542                 pr_debug("invalid image type specified.\n");
 543         spin_unlock(&rbu_data.lock);
 544
 545         rc = request_firmware_nowait(THIS_MODULE, FW_ACTION_NOHOTPLUG,
 546                 "dell_rbu", &rbu_device->dev, &context, callbackfn_rbu);
 547         if (rc)
 548                 printk(KERN_ERR
 549                         "dell_rbu:%s request_firmware_nowait failed"
 550                         " %d\n", __FUNCTION__, rc);
 551         else
 552                 rbu_data.entry_created = 1;
 553 }
 554
 555 static ssize_t read_rbu_image_type(struct kobject *kobj, char *buffer,
 556                         loff_t pos, size_t count)
 557 {
 558         int size = 0;
 559         if (!pos)
 560                 size = sprintf(buffer, "%s\n", image_type);
 561         return size;
 562 }
 563
 564 static ssize_t write_rbu_image_type(struct kobject *kobj, char *buffer,
 565                         loff_t pos, size_t count)
 566 {
 567         int rc = count;
 568         int req_firm_rc = 0;
 569         int i;
 570         spin_lock(&rbu_data.lock);
 571         /*
 572          * Find the first newline or space
 573          */
 574         for (i = 0; i < count; ++i)
 575                 if (buffer[i] == '\n' || buffer[i] == ' ') {
 576                         buffer[i] = '\0';
 577                         break;
 578                 }
 579         if (i == count)
 580                 buffer[count] = '\0';
 581
 582         if (strstr(buffer, "mono"))
 583                 strcpy(image_type, "mono");
 584         else if (strstr(buffer, "packet"))
 585                 strcpy(image_type, "packet");
 586         else if (strstr(buffer, "init")) {
 587                 /*
 588                  * If due to the user error the driver gets in a bad
 589                  * state where even though it is loaded , the
 590                  * /sys/class/firmware/dell_rbu entries are missing.
 591                  * to cover this situation the user can recreate entries
 592                  * by writing init to image_type.
 593                  */
 594                 if (!rbu_data.entry_created) {
 595                         spin_unlock(&rbu_data.lock);
 596                         req_firm_rc = request_firmware_nowait(THIS_MODULE,
 597                                 FW_ACTION_NOHOTPLUG, "dell_rbu",
 598                                 &rbu_device->dev, &context,
 599                                 callbackfn_rbu);
 600                         if (req_firm_rc) {
 601                                 printk(KERN_ERR
 602                                         "dell_rbu:%s request_firmware_nowait"
 603                                         " failed %d\n", __FUNCTION__, rc);
 604                                 rc = -EIO;
 605                         } else
 606                                 rbu_data.entry_created = 1;
 607
 608                         spin_lock(&rbu_data.lock);
 609                 }
 610         } else {
 611                 printk(KERN_WARNING "dell_rbu: image_type is invalid\n");
 612                 spin_unlock(&rbu_data.lock);
 613                 return -EINVAL;
 614         }
 615
 616         /* we must free all previous allocations */
 617         packet_empty_list();
 618         img_update_free();
 619         spin_unlock(&rbu_data.lock);
 620
 621         return rc;
 622 }
 623
 624 static struct bin_attribute rbu_data_attr = {
 625         .attr = {
 626                 .name = "data",
 627                 .owner = THIS_MODULE,
 628                 .mode = 0444,
 629         },
 630         .read = read_rbu_data,
 631 };
 632
 633 static struct bin_attribute rbu_image_type_attr = {
 634         .attr = {
 635                 .name = "image_type",
 636                 .owner = THIS_MODULE,
 637                 .mode = 0644,
 638         },
 639         .read = read_rbu_image_type,
 640         .write = write_rbu_image_type,
 641 };
 642
 643 static int __init dcdrbu_init(void)
 644 {
 645         int rc = 0;
 646         spin_lock_init(&rbu_data.lock);
 647
 648         init_packet_head();
 649         rbu_device =
 650                 platform_device_register_simple("dell_rbu", -1, NULL, 0);
 651         if (!rbu_device) {
 652                 printk(KERN_ERR
 653                         "dell_rbu:%s:platform_device_register_simple "
 654                         "failed\n", __FUNCTION__);
 655                 return -EIO;
 656         }
 657
 658         sysfs_create_bin_file(&rbu_device->dev.kobj, &rbu_data_attr);
 659         sysfs_create_bin_file(&rbu_device->dev.kobj, &rbu_image_type_attr);
 660
 661         rc = request_firmware_nowait(THIS_MODULE, FW_ACTION_NOHOTPLUG,
 662                 "dell_rbu", &rbu_device->dev, &context, callbackfn_rbu);
 663         if (rc)
 664                 printk(KERN_ERR "dell_rbu:%s:request_firmware_nowait"
 665                         " failed %d\n", __FUNCTION__, rc);
 666         else
 667                 rbu_data.entry_created = 1;
 668
 669         return rc;
 670
 671 }
 672
 673 static __exit void dcdrbu_exit(void)
 674 {
 675         spin_lock(&rbu_data.lock);
 676         packet_empty_list();
 677         img_update_free();
 678         spin_unlock(&rbu_data.lock);
 679         platform_device_unregister(rbu_device);
 680 }
 681
 682 module_exit(dcdrbu_exit);
 683 module_init(dcdrbu_init);