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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("1.0");
  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 } rbu_data;
  69
  70 static char image_type[MAX_IMAGE_LENGTH] = "mono";
  71 module_param_string(image_type, image_type, sizeof(image_type), 0);
  72 MODULE_PARM_DESC(image_type, "BIOS image type. choose- mono or packet");
  73
  74 struct packet_data {
  75         struct list_head list;
  76         size_t length;
  77         void *data;
  78         int ordernum;
  79 };
  80
  81 static struct packet_data packet_data_head;
  82
  83 static struct platform_device *rbu_device;
  84 static int context;
  85 static dma_addr_t dell_rbu_dmaaddr;
  86
  87 static void init_packet_head(void)
  88 {
  89         INIT_LIST_HEAD(&packet_data_head.list);
  90         rbu_data.packet_write_count = 0;
  91         rbu_data.packet_read_count = 0;
  92         rbu_data.num_packets = 0;
  93         rbu_data.packetsize = 0;
  94 }
  95
  96 static int fill_last_packet(void *data, size_t length)
  97 {
  98         struct list_head *ptemp_list;
  99         struct packet_data *packet = NULL;
 100         int packet_count = 0;
 101
 102         pr_debug("fill_last_packet: entry \n");
 103
 104         if (!rbu_data.num_packets) {
 105                 pr_debug("fill_last_packet: num_packets=0\n");
 106                 return -ENOMEM;
 107         }
 108
 109         packet_count = rbu_data.num_packets;
 110
 111         ptemp_list = (&packet_data_head.list)->prev;
 112
 113         packet = list_entry(ptemp_list, struct packet_data, list);
 114
 115         if ((rbu_data.packet_write_count + length) > rbu_data.packetsize) {
 116                 pr_debug("dell_rbu:%s: packet size data "
 117                          "overrun\n", __FUNCTION__);
 118                 return -EINVAL;
 119         }
 120
 121         pr_debug("fill_last_packet : buffer = %p\n", packet->data);
 122
 123         memcpy((packet->data + rbu_data.packet_write_count), data, length);
 124
 125         if ((rbu_data.packet_write_count + length) == rbu_data.packetsize) {
 126                 /*
 127                  * this was the last data chunk in the packet
 128                  * so reinitialize the packet data counter to zero
 129                  */
 130                 rbu_data.packet_write_count = 0;
 131         } else
 132                 rbu_data.packet_write_count += length;
 133
 134         pr_debug("fill_last_packet: exit \n");
 135         return 0;
 136 }
 137
 138 static int create_packet(size_t length)
 139 {
 140         struct packet_data *newpacket;
 141         int ordernum = 0;
 142
 143         pr_debug("create_packet: entry \n");
 144
 145         if (!rbu_data.packetsize) {
 146                 pr_debug("create_packet: packetsize not specified\n");
 147                 return -EINVAL;
 148         }
 149
 150         newpacket = kmalloc(sizeof(struct packet_data), GFP_KERNEL);
 151         if (!newpacket) {
 152                 printk(KERN_WARNING
 153                        "dell_rbu:%s: failed to allocate new "
 154                        "packet\n", __FUNCTION__);
 155                 return -ENOMEM;
 156         }
 157
 158         ordernum = get_order(length);
 159         /*
 160          * there is no upper limit on memory
 161          * address for packetized mechanism
 162          */
 163         newpacket->data = (unsigned char *)__get_free_pages(GFP_KERNEL,
 164                                                             ordernum);
 165
 166         pr_debug("create_packet: newpacket %p\n", newpacket->data);
 167
 168         if (!newpacket->data) {
 169                 printk(KERN_WARNING
 170                        "dell_rbu:%s: failed to allocate new "
 171                        "packet\n", __FUNCTION__);
 172                 kfree(newpacket);
 173                 return -ENOMEM;
 174         }
 175
 176         newpacket->ordernum = ordernum;
 177         ++rbu_data.num_packets;
 178         /*
 179          * initialize the newly created packet headers
 180          */
 181         INIT_LIST_HEAD(&newpacket->list);
 182         list_add_tail(&newpacket->list, &packet_data_head.list);
 183         /*
 184          * packets have fixed size
 185          */
 186         newpacket->length = rbu_data.packetsize;
 187
 188         pr_debug("create_packet: exit \n");
 189
 190         return 0;
 191 }
 192
 193 static int packetize_data(void *data, size_t length)
 194 {
 195         int rc = 0;
 196
 197         if (!rbu_data.packet_write_count) {
 198                 if ((rc = create_packet(length)))
 199                         return rc;
 200         }
 201         if ((rc = fill_last_packet(data, length)))
 202                 return rc;
 203
 204         return rc;
 205 }
 206
 207 static int
 208 do_packet_read(char *data, struct list_head *ptemp_list,
 209                int length, int bytes_read, int *list_read_count)
 210 {
 211         void *ptemp_buf;
 212         struct packet_data *newpacket = NULL;
 213         int bytes_copied = 0;
 214         int j = 0;
 215
 216         newpacket = list_entry(ptemp_list, struct packet_data, list);
 217         *list_read_count += newpacket->length;
 218
 219         if (*list_read_count > bytes_read) {
 220                 /* point to the start of unread data */
 221                 j = newpacket->length - (*list_read_count - bytes_read);
 222                 /* point to the offset in the packet buffer */
 223                 ptemp_buf = (u8 *) newpacket->data + j;
 224                 /*
 225                  * check if there is enough room in
 226                  * * the incoming buffer
 227                  */
 228                 if (length > (*list_read_count - bytes_read))
 229                         /*
 230                          * copy what ever is there in this
 231                          * packet and move on
 232                          */
 233                         bytes_copied = (*list_read_count - bytes_read);
 234                 else
 235                         /* copy the remaining */
 236                         bytes_copied = length;
 237                 memcpy(data, ptemp_buf, bytes_copied);
 238         }
 239         return bytes_copied;
 240 }
 241
 242 static int packet_read_list(char *data, size_t * pread_length)
 243 {
 244         struct list_head *ptemp_list;
 245         int temp_count = 0;
 246         int bytes_copied = 0;
 247         int bytes_read = 0;
 248         int remaining_bytes = 0;
 249         char *pdest = data;
 250
 251         /* check if we have any packets */
 252         if (0 == rbu_data.num_packets)
 253                 return -ENOMEM;
 254
 255         remaining_bytes = *pread_length;
 256         bytes_read = rbu_data.packet_read_count;
 257
 258         ptemp_list = (&packet_data_head.list)->next;
 259         while (!list_empty(ptemp_list)) {
 260                 bytes_copied = do_packet_read(pdest, ptemp_list,
 261                                               remaining_bytes, bytes_read,
 262                                               &temp_count);
 263                 remaining_bytes -= bytes_copied;
 264                 bytes_read += bytes_copied;
 265                 pdest += bytes_copied;
 266                 /*
 267                  * check if we reached end of buffer before reaching the
 268                  * last packet
 269                  */
 270                 if (remaining_bytes == 0)
 271                         break;
 272
 273                 ptemp_list = ptemp_list->next;
 274         }
 275         /*finally set the bytes read */
 276         *pread_length = bytes_read - rbu_data.packet_read_count;
 277         rbu_data.packet_read_count = bytes_read;
 278         return 0;
 279 }
 280
 281 static void packet_empty_list(void)
 282 {
 283         struct list_head *ptemp_list;
 284         struct list_head *pnext_list;
 285         struct packet_data *newpacket;
 286
 287         ptemp_list = (&packet_data_head.list)->next;
 288         while (!list_empty(ptemp_list)) {
 289                 newpacket =
 290                     list_entry(ptemp_list, struct packet_data, list);
 291                 pnext_list = ptemp_list->next;
 292                 list_del(ptemp_list);
 293                 ptemp_list = pnext_list;
 294                 /*
 295                  * zero out the RBU packet memory before freeing
 296                  * to make sure there are no stale RBU packets left in memory
 297                  */
 298                 memset(newpacket->data, 0, rbu_data.packetsize);
 299                 free_pages((unsigned long)newpacket->data,
 300                            newpacket->ordernum);
 301                 kfree(newpacket);
 302         }
 303         rbu_data.packet_write_count = 0;
 304         rbu_data.packet_read_count = 0;
 305         rbu_data.num_packets = 0;
 306         rbu_data.packetsize = 0;
 307 }
 308
 309 /*
 310  * img_update_free: Frees the buffer allocated for storing BIOS image
 311  * Always called with lock held and returned with lock held
 312  */
 313 static void img_update_free(void)
 314 {
 315         if (!rbu_data.image_update_buffer)
 316                 return;
 317         /*
 318          * zero out this buffer before freeing it to get rid of any stale
 319          * BIOS image copied in memory.
 320          */
 321         memset(rbu_data.image_update_buffer, 0,
 322                rbu_data.image_update_buffer_size);
 323         if (rbu_data.dma_alloc == 1)
 324                 dma_free_coherent(NULL, rbu_data.bios_image_size,
 325                                   rbu_data.image_update_buffer,
 326                                   dell_rbu_dmaaddr);
 327         else
 328                 free_pages((unsigned long)rbu_data.image_update_buffer,
 329                            rbu_data.image_update_ordernum);
 330
 331         /*
 332          * Re-initialize the rbu_data variables after a free
 333          */
 334         rbu_data.image_update_ordernum = -1;
 335         rbu_data.image_update_buffer = NULL;
 336         rbu_data.image_update_buffer_size = 0;
 337         rbu_data.bios_image_size = 0;
 338         rbu_data.dma_alloc = 0;
 339 }
 340
 341 /*
 342  * img_update_realloc: This function allocates the contiguous pages to
 343  * accommodate the requested size of data. The memory address and size
 344  * values are stored globally and on every call to this function the new
 345  * size is checked to see if more data is required than the existing size.
 346  * If true the previous memory is freed and new allocation is done to
 347  * accommodate the new size. If the incoming size is less then than the
 348  * already allocated size, then that memory is reused. This function is
 349  * called with lock held and returns with lock held.
 350  */
 351 static int img_update_realloc(unsigned long size)
 352 {
 353         unsigned char *image_update_buffer = NULL;
 354         unsigned long rc;
 355         unsigned long img_buf_phys_addr;
 356         int ordernum;
 357         int dma_alloc = 0;
 358
 359         /*
 360          * check if the buffer of sufficient size has been
 361          * already allocated
 362          */
 363         if (rbu_data.image_update_buffer_size >= size) {
 364                 /*
 365                  * check for corruption
 366                  */
 367                 if ((size != 0) && (rbu_data.image_update_buffer == NULL)) {
 368                         printk(KERN_ERR "dell_rbu:%s: corruption "
 369                                "check failed\n", __FUNCTION__);
 370                         return -EINVAL;
 371                 }
 372                 /*
 373                  * we have a valid pre-allocated buffer with
 374                  * sufficient size
 375                  */
 376                 return 0;
 377         }
 378
 379         /*
 380          * free any previously allocated buffer
 381          */
 382         img_update_free();
 383
 384         spin_unlock(&rbu_data.lock);
 385
 386         ordernum = get_order(size);
 387         image_update_buffer =
 388             (unsigned char *)__get_free_pages(GFP_KERNEL, ordernum);
 389
 390         img_buf_phys_addr =
 391             (unsigned long)virt_to_phys(image_update_buffer);
 392
 393         if (img_buf_phys_addr > BIOS_SCAN_LIMIT) {
 394                 free_pages((unsigned long)image_update_buffer, ordernum);
 395                 ordernum = -1;
 396                 image_update_buffer = dma_alloc_coherent(NULL, size,
 397                                                          &dell_rbu_dmaaddr,
 398                                                          GFP_KERNEL);
 399                 dma_alloc = 1;
 400         }
 401
 402         spin_lock(&rbu_data.lock);
 403
 404         if (image_update_buffer != NULL) {
 405                 rbu_data.image_update_buffer = image_update_buffer;
 406                 rbu_data.image_update_buffer_size = size;
 407                 rbu_data.bios_image_size =
 408                     rbu_data.image_update_buffer_size;
 409                 rbu_data.image_update_ordernum = ordernum;
 410                 rbu_data.dma_alloc = dma_alloc;
 411                 rc = 0;
 412         } else {
 413                 pr_debug("Not enough memory for image update:"
 414                          "size = %ld\n", size);
 415                 rc = -ENOMEM;
 416         }
 417
 418         return rc;
 419 }
 420
 421 static ssize_t read_packet_data(char *buffer, loff_t pos, size_t count)
 422 {
 423         int retval;
 424         size_t bytes_left;
 425         size_t data_length;
 426         char *ptempBuf = buffer;
 427         unsigned long imagesize;
 428
 429         /* check to see if we have something to return */
 430         if (rbu_data.num_packets == 0) {
 431                 pr_debug("read_packet_data: no packets written\n");
 432                 retval = -ENOMEM;
 433                 goto read_rbu_data_exit;
 434         }
 435
 436         imagesize = rbu_data.num_packets * rbu_data.packetsize;
 437
 438         if (pos > imagesize) {
 439                 retval = 0;
 440                 printk(KERN_WARNING "dell_rbu:read_packet_data: "
 441                        "data underrun\n");
 442                 goto read_rbu_data_exit;
 443         }
 444
 445         bytes_left = imagesize - pos;
 446         data_length = min(bytes_left, count);
 447
 448         if ((retval = packet_read_list(ptempBuf, &data_length)) < 0)
 449                 goto read_rbu_data_exit;
 450
 451         if ((pos + count) > imagesize) {
 452                 rbu_data.packet_read_count = 0;
 453                 /* this was the last copy */
 454                 retval = bytes_left;
 455         } else
 456                 retval = count;
 457
 458       read_rbu_data_exit:
 459         return retval;
 460 }
 461
 462 static ssize_t read_rbu_mono_data(char *buffer, loff_t pos, size_t count)
 463 {
 464         unsigned char *ptemp = NULL;
 465         size_t bytes_left = 0;
 466         size_t data_length = 0;
 467         ssize_t ret_count = 0;
 468
 469         /* check to see if we have something to return */
 470         if ((rbu_data.image_update_buffer == NULL) ||
 471             (rbu_data.bios_image_size == 0)) {
 472                 pr_debug("read_rbu_data_mono: image_update_buffer %p ,"
 473                          "bios_image_size %lu\n",
 474                          rbu_data.image_update_buffer,
 475                          rbu_data.bios_image_size);
 476                 ret_count = -ENOMEM;
 477                 goto read_rbu_data_exit;
 478         }
 479
 480         if (pos > rbu_data.bios_image_size) {
 481                 ret_count = 0;
 482                 goto read_rbu_data_exit;
 483         }
 484
 485         bytes_left = rbu_data.bios_image_size - pos;
 486         data_length = min(bytes_left, count);
 487
 488         ptemp = rbu_data.image_update_buffer;
 489         memcpy(buffer, (ptemp + pos), data_length);
 490
 491         if ((pos + count) > rbu_data.bios_image_size)
 492                 /* this was the last copy */
 493                 ret_count = bytes_left;
 494         else
 495                 ret_count = count;
 496       read_rbu_data_exit:
 497         return ret_count;
 498 }
 499
 500 static ssize_t
 501 read_rbu_data(struct kobject *kobj, char *buffer, loff_t pos, size_t count)
 502 {
 503         ssize_t ret_count = 0;
 504
 505         spin_lock(&rbu_data.lock);
 506
 507         if (!strcmp(image_type, "mono"))
 508                 ret_count = read_rbu_mono_data(buffer, pos, count);
 509         else if (!strcmp(image_type, "packet"))
 510                 ret_count = read_packet_data(buffer, pos, count);
 511         else
 512                 pr_debug("read_rbu_data: invalid image type specified\n");
 513
 514         spin_unlock(&rbu_data.lock);
 515         return ret_count;
 516 }
 517
 518 static ssize_t
 519 read_rbu_image_type(struct kobject *kobj, char *buffer, loff_t pos,
 520                     size_t count)
 521 {
 522         int size = 0;
 523         if (!pos)
 524                 size = sprintf(buffer, "%s\n", image_type);
 525         return size;
 526 }
 527
 528 static ssize_t
 529 write_rbu_image_type(struct kobject *kobj, char *buffer, loff_t pos,
 530                      size_t count)
 531 {
 532         int rc = count;
 533         spin_lock(&rbu_data.lock);
 534
 535         if (strlen(buffer) < MAX_IMAGE_LENGTH)
 536                 sscanf(buffer, "%s", image_type);
 537         else
 538                 printk(KERN_WARNING "dell_rbu: image_type is invalid"
 539                        "max chars = %d, \n incoming str--%s-- \n",
 540                        MAX_IMAGE_LENGTH, buffer);
 541
 542         /* we must free all previous allocations */
 543         packet_empty_list();
 544         img_update_free();
 545
 546         spin_unlock(&rbu_data.lock);
 547         return rc;
 548
 549 }
 550
 551 static struct bin_attribute rbu_data_attr = {
 552         .attr = {.name = "data",.owner = THIS_MODULE,.mode = 0444},
 553         .read = read_rbu_data,
 554 };
 555
 556 static struct bin_attribute rbu_image_type_attr = {
 557         .attr = {.name = "image_type",.owner = THIS_MODULE,.mode = 0644},
 558         .read = read_rbu_image_type,
 559         .write = write_rbu_image_type,
 560 };
 561
 562 static void callbackfn_rbu(const struct firmware *fw, void *context)
 563 {
 564         int rc = 0;
 565
 566         if (!fw || !fw->size)
 567                 return;
 568
 569         spin_lock(&rbu_data.lock);
 570         if (!strcmp(image_type, "mono")) {
 571                 if (!img_update_realloc(fw->size))
 572                         memcpy(rbu_data.image_update_buffer,
 573                                fw->data, fw->size);
 574         } else if (!strcmp(image_type, "packet")) {
 575                 if (!rbu_data.packetsize)
 576                         rbu_data.packetsize = fw->size;
 577                 else if (rbu_data.packetsize != fw->size) {
 578                         packet_empty_list();
 579                         rbu_data.packetsize = fw->size;
 580                 }
 581                 packetize_data(fw->data, fw->size);
 582         } else
 583                 pr_debug("invalid image type specified.\n");
 584         spin_unlock(&rbu_data.lock);
 585
 586         rc = request_firmware_nowait(THIS_MODULE, FW_ACTION_NOHOTPLUG,
 587                                      "dell_rbu", &rbu_device->dev,
 588                                      &context, callbackfn_rbu);
 589         if (rc)
 590                 printk(KERN_ERR
 591                        "dell_rbu:%s request_firmware_nowait failed"
 592                        " %d\n", __FUNCTION__, rc);
 593 }
 594
 595 static int __init dcdrbu_init(void)
 596 {
 597         int rc = 0;
 598         spin_lock_init(&rbu_data.lock);
 599
 600         init_packet_head();
 601         rbu_device =
 602             platform_device_register_simple("dell_rbu", -1, NULL, 0);
 603         if (!rbu_device) {
 604                 printk(KERN_ERR
 605                        "dell_rbu:%s:platform_device_register_simple "
 606                        "failed\n", __FUNCTION__);
 607                 return -EIO;
 608         }
 609
 610         sysfs_create_bin_file(&rbu_device->dev.kobj, &rbu_data_attr);
 611         sysfs_create_bin_file(&rbu_device->dev.kobj, &rbu_image_type_attr);
 612
 613         rc = request_firmware_nowait(THIS_MODULE, FW_ACTION_NOHOTPLUG,
 614                                      "dell_rbu", &rbu_device->dev,
 615                                      &context, callbackfn_rbu);
 616         if (rc)
 617                 printk(KERN_ERR "dell_rbu:%s:request_firmware_nowait"
 618                        " failed %d\n", __FUNCTION__, rc);
 619
 620         return rc;
 621
 622 }
 623
 624 static __exit void dcdrbu_exit(void)
 625 {
 626         spin_lock(&rbu_data.lock);
 627         packet_empty_list();
 628         img_update_free();
 629         spin_unlock(&rbu_data.lock);
 630         platform_device_unregister(rbu_device);
 631 }
 632
 633 module_exit(dcdrbu_exit);
 634 module_init(dcdrbu_init);