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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
  89 init_packet_head(void)
  90 {
  91         INIT_LIST_HEAD(&packet_data_head.list);
  92         rbu_data.packet_write_count = 0;
  93         rbu_data.packet_read_count = 0;
  94         rbu_data.num_packets = 0;
  95         rbu_data.packetsize = 0;
  96 }
  97
  98 static int
  99 fill_last_packet(void *data, size_t length)
 100 {
 101         struct list_head *ptemp_list;
 102         struct packet_data *packet = NULL;
 103         int packet_count = 0;
 104
 105         pr_debug("fill_last_packet: entry \n");
 106
 107         if (!rbu_data.num_packets) {
 108                 pr_debug("fill_last_packet: num_packets=0\n");
 109                 return -ENOMEM;
 110         }
 111
 112         packet_count = rbu_data.num_packets;
 113
 114         ptemp_list = (&packet_data_head.list)->prev;
 115
 116         packet = list_entry(ptemp_list, struct packet_data, list);
 117
 118         if ((rbu_data.packet_write_count + length) > rbu_data.packetsize) {
 119                 pr_debug("dell_rbu:%s: packet size data "
 120                         "overrun\n", __FUNCTION__);
 121                 return -EINVAL;
 122         }
 123
 124         pr_debug("fill_last_packet : buffer = %p\n", packet->data);
 125
 126         memcpy((packet->data + rbu_data.packet_write_count), data, length);
 127
 128         if ((rbu_data.packet_write_count + length) == rbu_data.packetsize) {
 129                 /*
 130                  * this was the last data chunk in the packet
 131                  * so reinitialize the packet data counter to zero
 132                  */
 133                 rbu_data.packet_write_count = 0;
 134         } else
 135                 rbu_data.packet_write_count += length;
 136
 137         pr_debug("fill_last_packet: exit \n");
 138         return 0;
 139 }
 140
 141 static int
 142 create_packet(size_t length)
 143 {
 144         struct packet_data *newpacket;
 145         int ordernum = 0;
 146
 147         pr_debug("create_packet: entry \n");
 148
 149         if (!rbu_data.packetsize) {
 150                 pr_debug("create_packet: packetsize not specified\n");
 151                 return -EINVAL;
 152         }
 153         spin_unlock(&rbu_data.lock);
 154         newpacket = kmalloc(sizeof (struct packet_data), GFP_KERNEL);
 155         spin_lock(&rbu_data.lock);
 156
 157         if (!newpacket) {
 158                 printk(KERN_WARNING
 159                         "dell_rbu:%s: failed to allocate new "
 160                         "packet\n", __FUNCTION__);
 161                 return -ENOMEM;
 162         }
 163
 164         ordernum = get_order(length);
 165         /*
 166          * there is no upper limit on memory
 167          * address for packetized mechanism
 168          */
 169         spin_unlock(&rbu_data.lock);
 170         newpacket->data = (unsigned char *) __get_free_pages(GFP_KERNEL,
 171                 ordernum);
 172         spin_lock(&rbu_data.lock);
 173
 174         pr_debug("create_packet: newpacket %p\n", newpacket->data);
 175
 176         if (!newpacket->data) {
 177                 printk(KERN_WARNING
 178                         "dell_rbu:%s: failed to allocate new "
 179                         "packet\n", __FUNCTION__);
 180                 kfree(newpacket);
 181                 return -ENOMEM;
 182         }
 183
 184         newpacket->ordernum = ordernum;
 185         ++rbu_data.num_packets;
 186         /*
 187          * initialize the newly created packet headers
 188          */
 189         INIT_LIST_HEAD(&newpacket->list);
 190         list_add_tail(&newpacket->list, &packet_data_head.list);
 191         /*
 192          * packets have fixed size
 193          */
 194         newpacket->length = rbu_data.packetsize;
 195
 196         pr_debug("create_packet: exit \n");
 197
 198         return 0;
 199 }
 200
 201 static int
 202 packetize_data(void *data, size_t length)
 203 {
 204         int rc = 0;
 205
 206         if (!rbu_data.packet_write_count) {
 207                 if ((rc = create_packet(length)))
 208                         return rc;
 209         }
 210         if ((rc = fill_last_packet(data, length)))
 211                 return rc;
 212
 213         return rc;
 214 }
 215
 216 static int
 217 do_packet_read(char *data, struct list_head *ptemp_list,
 218         int length, int bytes_read, int *list_read_count)
 219 {
 220         void *ptemp_buf;
 221         struct packet_data *newpacket = NULL;
 222         int bytes_copied = 0;
 223         int j = 0;
 224
 225         newpacket = list_entry(ptemp_list, struct packet_data, list);
 226         *list_read_count += newpacket->length;
 227
 228         if (*list_read_count > bytes_read) {
 229                 /* point to the start of unread data */
 230                 j = newpacket->length - (*list_read_count - bytes_read);
 231                 /* point to the offset in the packet buffer */
 232                 ptemp_buf = (u8 *) newpacket->data + j;
 233                 /*
 234                  * check if there is enough room in
 235                  * * the incoming buffer
 236                  */
 237                 if (length > (*list_read_count - bytes_read))
 238                         /*
 239                          * copy what ever is there in this
 240                          * packet and move on
 241                          */
 242                         bytes_copied = (*list_read_count - bytes_read);
 243                 else
 244                         /* copy the remaining */
 245                         bytes_copied = length;
 246                 memcpy(data, ptemp_buf, bytes_copied);
 247         }
 248         return bytes_copied;
 249 }
 250
 251 static int
 252 packet_read_list(char *data, size_t * pread_length)
 253 {
 254         struct list_head *ptemp_list;
 255         int temp_count = 0;
 256         int bytes_copied = 0;
 257         int bytes_read = 0;
 258         int remaining_bytes = 0;
 259         char *pdest = data;
 260
 261         /* check if we have any packets */
 262         if (0 == rbu_data.num_packets)
 263                 return -ENOMEM;
 264
 265         remaining_bytes = *pread_length;
 266         bytes_read = rbu_data.packet_read_count;
 267
 268         ptemp_list = (&packet_data_head.list)->next;
 269         while (!list_empty(ptemp_list)) {
 270                 bytes_copied = do_packet_read(pdest, ptemp_list,
 271                         remaining_bytes, bytes_read, &temp_count);
 272                 remaining_bytes -= bytes_copied;
 273                 bytes_read += bytes_copied;
 274                 pdest += bytes_copied;
 275                 /*
 276                  * check if we reached end of buffer before reaching the
 277                  * last packet
 278                  */
 279                 if (remaining_bytes == 0)
 280                         break;
 281
 282                 ptemp_list = ptemp_list->next;
 283         }
 284         /*finally set the bytes read */
 285         *pread_length = bytes_read - rbu_data.packet_read_count;
 286         rbu_data.packet_read_count = bytes_read;
 287         return 0;
 288 }
 289
 290 static void
 291 packet_empty_list(void)
 292 {
 293         struct list_head *ptemp_list;
 294         struct list_head *pnext_list;
 295         struct packet_data *newpacket;
 296
 297         ptemp_list = (&packet_data_head.list)->next;
 298         while (!list_empty(ptemp_list)) {
 299                 newpacket =
 300                         list_entry(ptemp_list, struct packet_data, list);
 301                 pnext_list = ptemp_list->next;
 302                 list_del(ptemp_list);
 303                 ptemp_list = pnext_list;
 304                 /*
 305                  * zero out the RBU packet memory before freeing
 306                  * to make sure there are no stale RBU packets left in memory
 307                  */
 308                 memset(newpacket->data, 0, rbu_data.packetsize);
 309                 free_pages((unsigned long) newpacket->data,
 310                         newpacket->ordernum);
 311                 kfree(newpacket);
 312         }
 313         rbu_data.packet_write_count = 0;
 314         rbu_data.packet_read_count = 0;
 315         rbu_data.num_packets = 0;
 316         rbu_data.packetsize = 0;
 317 }
 318
 319 /*
 320  * img_update_free: Frees the buffer allocated for storing BIOS image
 321  * Always called with lock held and returned with lock held
 322  */
 323 static void
 324 img_update_free(void)
 325 {
 326         if (!rbu_data.image_update_buffer)
 327                 return;
 328         /*
 329          * zero out this buffer before freeing it to get rid of any stale
 330          * BIOS image copied in memory.
 331          */
 332         memset(rbu_data.image_update_buffer, 0,
 333                 rbu_data.image_update_buffer_size);
 334         if (rbu_data.dma_alloc == 1)
 335                 dma_free_coherent(NULL, rbu_data.bios_image_size,
 336                         rbu_data.image_update_buffer, dell_rbu_dmaaddr);
 337         else
 338                 free_pages((unsigned long) rbu_data.image_update_buffer,
 339                         rbu_data.image_update_ordernum);
 340
 341         /*
 342          * Re-initialize the rbu_data variables after a free
 343          */
 344         rbu_data.image_update_ordernum = -1;
 345         rbu_data.image_update_buffer = NULL;
 346         rbu_data.image_update_buffer_size = 0;
 347         rbu_data.bios_image_size = 0;
 348         rbu_data.dma_alloc = 0;
 349 }
 350
 351 /*
 352  * img_update_realloc: This function allocates the contiguous pages to
 353  * accommodate the requested size of data. The memory address and size
 354  * values are stored globally and on every call to this function the new
 355  * size is checked to see if more data is required than the existing size.
 356  * If true the previous memory is freed and new allocation is done to
 357  * accommodate the new size. If the incoming size is less then than the
 358  * already allocated size, then that memory is reused. This function is
 359  * called with lock held and returns with lock held.
 360  */
 361 static int
 362 img_update_realloc(unsigned long size)
 363 {
 364         unsigned char *image_update_buffer = NULL;
 365         unsigned long rc;
 366         unsigned long img_buf_phys_addr;
 367         int ordernum;
 368         int dma_alloc = 0;
 369
 370         /*
 371          * check if the buffer of sufficient size has been
 372          * already allocated
 373          */
 374         if (rbu_data.image_update_buffer_size >= size) {
 375                 /*
 376                  * check for corruption
 377                  */
 378                 if ((size != 0) && (rbu_data.image_update_buffer == NULL)) {
 379                         printk(KERN_ERR "dell_rbu:%s: corruption "
 380                                 "check failed\n", __FUNCTION__);
 381                         return -EINVAL;
 382                 }
 383                 /*
 384                  * we have a valid pre-allocated buffer with
 385                  * sufficient size
 386                  */
 387                 return 0;
 388         }
 389
 390         /*
 391          * free any previously allocated buffer
 392          */
 393         img_update_free();
 394
 395         spin_unlock(&rbu_data.lock);
 396
 397         ordernum = get_order(size);
 398         image_update_buffer =
 399                 (unsigned char *) __get_free_pages(GFP_KERNEL, ordernum);
 400
 401         img_buf_phys_addr =
 402                 (unsigned long) virt_to_phys(image_update_buffer);
 403
 404         if (img_buf_phys_addr > BIOS_SCAN_LIMIT) {
 405                 free_pages((unsigned long) image_update_buffer, ordernum);
 406                 ordernum = -1;
 407                 image_update_buffer = dma_alloc_coherent(NULL, size,
 408                         &dell_rbu_dmaaddr, GFP_KERNEL);
 409                 dma_alloc = 1;
 410         }
 411
 412         spin_lock(&rbu_data.lock);
 413
 414         if (image_update_buffer != NULL) {
 415                 rbu_data.image_update_buffer = image_update_buffer;
 416                 rbu_data.image_update_buffer_size = size;
 417                 rbu_data.bios_image_size =
 418                         rbu_data.image_update_buffer_size;
 419                 rbu_data.image_update_ordernum = ordernum;
 420                 rbu_data.dma_alloc = dma_alloc;
 421                 rc = 0;
 422         } else {
 423                 pr_debug("Not enough memory for image update:"
 424                         "size = %ld\n", size);
 425                 rc = -ENOMEM;
 426         }
 427
 428         return rc;
 429 }
 430
 431 static ssize_t
 432 read_packet_data(char *buffer, loff_t pos, size_t count)
 433 {
 434         int retval;
 435         size_t bytes_left;
 436         size_t data_length;
 437         char *ptempBuf = buffer;
 438         unsigned long imagesize;
 439
 440         /* check to see if we have something to return */
 441         if (rbu_data.num_packets == 0) {
 442                 pr_debug("read_packet_data: no packets written\n");
 443                 retval = -ENOMEM;
 444                 goto read_rbu_data_exit;
 445         }
 446
 447         imagesize = rbu_data.num_packets * rbu_data.packetsize;
 448
 449         if (pos > imagesize) {
 450                 retval = 0;
 451                 printk(KERN_WARNING "dell_rbu:read_packet_data: "
 452                         "data underrun\n");
 453                 goto read_rbu_data_exit;
 454         }
 455
 456         bytes_left = imagesize - pos;
 457         data_length = min(bytes_left, count);
 458
 459         if ((retval = packet_read_list(ptempBuf, &data_length)) < 0)
 460                 goto read_rbu_data_exit;
 461
 462         if ((pos + count) > imagesize) {
 463                 rbu_data.packet_read_count = 0;
 464                 /* this was the last copy */
 465                 retval = bytes_left;
 466         } else
 467                 retval = count;
 468
 469       read_rbu_data_exit:
 470         return retval;
 471 }
 472
 473 static ssize_t
 474 read_rbu_mono_data(char *buffer, loff_t pos, size_t count)
 475 {
 476         unsigned char *ptemp = NULL;
 477         size_t bytes_left = 0;
 478         size_t data_length = 0;
 479         ssize_t ret_count = 0;
 480
 481         /* check to see if we have something to return */
 482         if ((rbu_data.image_update_buffer == NULL) ||
 483                 (rbu_data.bios_image_size == 0)) {
 484                 pr_debug("read_rbu_data_mono: image_update_buffer %p ,"
 485                         "bios_image_size %lu\n",
 486                         rbu_data.image_update_buffer,
 487                         rbu_data.bios_image_size);
 488                 ret_count = -ENOMEM;
 489                 goto read_rbu_data_exit;
 490         }
 491
 492         if (pos > rbu_data.bios_image_size) {
 493                 ret_count = 0;
 494                 goto read_rbu_data_exit;
 495         }
 496
 497         bytes_left = rbu_data.bios_image_size - pos;
 498         data_length = min(bytes_left, count);
 499
 500         ptemp = rbu_data.image_update_buffer;
 501         memcpy(buffer, (ptemp + pos), data_length);
 502
 503         if ((pos + count) > rbu_data.bios_image_size)
 504                 /* this was the last copy */
 505                 ret_count = bytes_left;
 506         else
 507                 ret_count = count;
 508       read_rbu_data_exit:
 509         return ret_count;
 510 }
 511
 512 static ssize_t
 513 read_rbu_data(struct kobject *kobj, char *buffer, loff_t pos, size_t count)
 514 {
 515         ssize_t ret_count = 0;
 516
 517         spin_lock(&rbu_data.lock);
 518
 519         if (!strcmp(image_type, "mono"))
 520                 ret_count = read_rbu_mono_data(buffer, pos, count);
 521         else if (!strcmp(image_type, "packet"))
 522                 ret_count = read_packet_data(buffer, pos, count);
 523         else
 524                 pr_debug("read_rbu_data: invalid image type specified\n");
 525
 526         spin_unlock(&rbu_data.lock);
 527         return ret_count;
 528 }
 529
 530 static void
 531 callbackfn_rbu(const struct firmware *fw, void *context)
 532 {
 533         int rc = 0;
 534
 535         if (!fw || !fw->size) {
 536                 rbu_data.entry_created = 0;
 537                 return;
 538         }
 539
 540         spin_lock(&rbu_data.lock);
 541         if (!strcmp(image_type, "mono")) {
 542                 if (!img_update_realloc(fw->size))
 543                         memcpy(rbu_data.image_update_buffer,
 544                                 fw->data, fw->size);
 545         } else if (!strcmp(image_type, "packet")) {
 546                 if (!rbu_data.packetsize)
 547                         rbu_data.packetsize = fw->size;
 548                 else if (rbu_data.packetsize != fw->size) {
 549                         packet_empty_list();
 550                         rbu_data.packetsize = fw->size;
 551                 }
 552                 packetize_data(fw->data, fw->size);
 553         } else
 554                 pr_debug("invalid image type specified.\n");
 555         spin_unlock(&rbu_data.lock);
 556
 557         rc = request_firmware_nowait(THIS_MODULE, FW_ACTION_NOHOTPLUG,
 558                 "dell_rbu", &rbu_device->dev, &context, callbackfn_rbu);
 559         if (rc)
 560                 printk(KERN_ERR
 561                         "dell_rbu:%s request_firmware_nowait failed"
 562                         " %d\n", __FUNCTION__, rc);
 563         else
 564                 rbu_data.entry_created = 1;
 565 }
 566
 567 static ssize_t
 568 read_rbu_image_type(struct kobject *kobj, char *buffer, loff_t pos,
 569         size_t count)
 570 {
 571         int size = 0;
 572         if (!pos)
 573                 size = sprintf(buffer, "%s\n", image_type);
 574         return size;
 575 }
 576
 577 static ssize_t
 578 write_rbu_image_type(struct kobject *kobj, char *buffer, loff_t pos,
 579         size_t count)
 580 {
 581         int rc = count;
 582         int req_firm_rc = 0;
 583         int i;
 584         spin_lock(&rbu_data.lock);
 585         /*
 586          * Find the first newline or space
 587          */
 588         for (i = 0; i < count; ++i)
 589                 if (buffer[i] == '\n' || buffer[i] == ' ') {
 590                         buffer[i] = '\0';
 591                         break;
 592                 }
 593         if (i == count)
 594                 buffer[count] = '\0';
 595
 596         if (strstr(buffer, "mono"))
 597                 strcpy(image_type, "mono");
 598         else if (strstr(buffer, "packet"))
 599                 strcpy(image_type, "packet");
 600         else if (strstr(buffer, "init")) {
 601                 /*
 602                  * If due to the user error the driver gets in a bad
 603                  * state where even though it is loaded , the
 604                  * /sys/class/firmware/dell_rbu entries are missing.
 605                  * to cover this situation the user can recreate entries
 606                  * by writing init to image_type.
 607                  */
 608                 if (!rbu_data.entry_created) {
 609                         spin_unlock(&rbu_data.lock);
 610                         req_firm_rc = request_firmware_nowait(THIS_MODULE,
 611                                 FW_ACTION_NOHOTPLUG, "dell_rbu",
 612                                 &rbu_device->dev, &context,
 613                                 callbackfn_rbu);
 614                         if (req_firm_rc) {
 615                                 printk(KERN_ERR
 616                                         "dell_rbu:%s request_firmware_nowait"
 617                                         " failed %d\n", __FUNCTION__, rc);
 618                                 rc = -EIO;
 619                         } else
 620                                 rbu_data.entry_created = 1;
 621
 622                         spin_lock(&rbu_data.lock);
 623                 }
 624         } else {
 625                 printk(KERN_WARNING "dell_rbu: image_type is invalid\n");
 626                 spin_unlock(&rbu_data.lock);
 627                 return -EINVAL;
 628         }
 629
 630         /* we must free all previous allocations */
 631         packet_empty_list();
 632         img_update_free();
 633         spin_unlock(&rbu_data.lock);
 634
 635         return rc;
 636 }
 637
 638 static struct bin_attribute rbu_data_attr = {
 639         .attr = {.name = "data",.owner = THIS_MODULE,.mode = 0444},
 640         .read = read_rbu_data,
 641 };
 642
 643 static struct bin_attribute rbu_image_type_attr = {
 644         .attr = {.name = "image_type",.owner = THIS_MODULE,.mode = 0644},
 645         .read = read_rbu_image_type,
 646         .write = write_rbu_image_type,
 647 };
 648
 649 static int __init
 650 dcdrbu_init(void)
 651 {
 652         int rc = 0;
 653         spin_lock_init(&rbu_data.lock);
 654
 655         init_packet_head();
 656         rbu_device =
 657                 platform_device_register_simple("dell_rbu", -1, NULL, 0);
 658         if (!rbu_device) {
 659                 printk(KERN_ERR
 660                         "dell_rbu:%s:platform_device_register_simple "
 661                         "failed\n", __FUNCTION__);
 662                 return -EIO;
 663         }
 664
 665         sysfs_create_bin_file(&rbu_device->dev.kobj, &rbu_data_attr);
 666         sysfs_create_bin_file(&rbu_device->dev.kobj, &rbu_image_type_attr);
 667
 668         rc = request_firmware_nowait(THIS_MODULE, FW_ACTION_NOHOTPLUG,
 669                 "dell_rbu", &rbu_device->dev, &context, callbackfn_rbu);
 670         if (rc)
 671                 printk(KERN_ERR "dell_rbu:%s:request_firmware_nowait"
 672                         " failed %d\n", __FUNCTION__, rc);
 673         else
 674                 rbu_data.entry_created = 1;
 675
 676         return rc;
 677
 678 }
 679
 680 static __exit void
 681 dcdrbu_exit(void)
 682 {
 683         spin_lock(&rbu_data.lock);
 684         packet_empty_list();
 685         img_update_free();
 686         spin_unlock(&rbu_data.lock);
 687         platform_device_unregister(rbu_device);
 688 }
 689
 690 module_exit(dcdrbu_exit);
 691 module_init(dcdrbu_init);