drivers/s390/block/xpram.c

   1 /*
   2  * Xpram.c -- the S/390 expanded memory RAM-disk
   3  *
   4  * significant parts of this code are based on
   5  * the sbull device driver presented in
   6  * A. Rubini: Linux Device Drivers
   7  *
   8  * Author of XPRAM specific coding: Reinhard Buendgen
   9  *                                  buendgen@de.ibm.com
  10  * Rewrite for 2.5: Martin Schwidefsky <schwidefsky@de.ibm.com>
  11  *
  12  * External interfaces:
  13  *   Interfaces to linux kernel
  14  *        xpram_setup: read kernel parameters
  15  *   Device specific file operations
  16  *        xpram_iotcl
  17  *        xpram_open
  18  *
  19  * "ad-hoc" partitioning:
  20  *    the expanded memory can be partitioned among several devices
  21  *    (with different minors). The partitioning set up can be
  22  *    set by kernel or module parameters (int devs & int sizes[])
  23  *
  24  * Potential future improvements:
  25  *   generic hard disk support to replace ad-hoc partitioning
  26  */
  27
  28 #define KMSG_COMPONENT "xpram"
  29 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  30
  31 #include <linux/module.h>
  32 #include <linux/moduleparam.h>
  33 #include <linux/ctype.h>  /* isdigit, isxdigit */
  34 #include <linux/errno.h>
  35 #include <linux/init.h>
  36 #include <linux/slab.h>
  37 #include <linux/blkdev.h>
  38 #include <linux/blkpg.h>
  39 #include <linux/hdreg.h>  /* HDIO_GETGEO */
  40 #include <linux/sysdev.h>
  41 #include <linux/bio.h>
  42 #include <linux/suspend.h>
  43 #include <linux/platform_device.h>
  44 #include <asm/uaccess.h>
  45 #include <asm/checksum.h>
  46
  47 #define XPRAM_NAME      "xpram"
  48 #define XPRAM_DEVS      1       /* one partition */
  49 #define XPRAM_MAX_DEVS  32      /* maximal number of devices (partitions) */
  50
  51 typedef struct {
  52         unsigned int    size;           /* size of xpram segment in pages */
  53         unsigned int    offset;         /* start page of xpram segment */
  54         unsigned int    csum;           /* partition checksum for suspend */
  55 } xpram_device_t;
  56
  57 static xpram_device_t xpram_devices[XPRAM_MAX_DEVS];
  58 static unsigned int xpram_sizes[XPRAM_MAX_DEVS];
  59 static struct gendisk *xpram_disks[XPRAM_MAX_DEVS];
  60 static struct request_queue *xpram_queues[XPRAM_MAX_DEVS];
  61 static unsigned int xpram_pages;
  62 static int xpram_devs;
  63
  64 /*
  65  * Parameter parsing functions.
  66  */
  67 static int __initdata devs = XPRAM_DEVS;
  68 static char __initdata *sizes[XPRAM_MAX_DEVS];
  69
  70 module_param(devs, int, 0);
  71 module_param_array(sizes, charp, NULL, 0);
  72
  73 MODULE_PARM_DESC(devs, "number of devices (\"partitions\"), " \
  74                  "the default is " __MODULE_STRING(XPRAM_DEVS) "\n");
  75 MODULE_PARM_DESC(sizes, "list of device (partition) sizes " \
  76                  "the defaults are 0s \n" \
  77                  "All devices with size 0 equally partition the "
  78                  "remaining space on the expanded strorage not "
  79                  "claimed by explicit sizes\n");
  80 MODULE_LICENSE("GPL");
  81
  82 /*
  83  * Copy expanded memory page (4kB) into main memory
  84  * Arguments
  85  *           page_addr:    address of target page
  86  *           xpage_index:  index of expandeded memory page
  87  * Return value
  88  *           0:            if operation succeeds
  89  *           -EIO:         if pgin failed
  90  *           -ENXIO:       if xpram has vanished
  91  */
  92 static int xpram_page_in (unsigned long page_addr, unsigned int xpage_index)
  93 {
  94         int cc = 2;     /* return unused cc 2 if pgin traps */
  95
  96         asm volatile(
  97                 "       .insn   rre,0xb22e0000,%1,%2\n"  /* pgin %1,%2 */
  98                 "0:     ipm     %0\n"
  99                 "       srl     %0,28\n"
 100                 "1:\n"
 101                 EX_TABLE(0b,1b)
 102                 : "+d" (cc) : "a" (__pa(page_addr)), "d" (xpage_index) : "cc");
 103         if (cc == 3)
 104                 return -ENXIO;
 105         if (cc == 2)
 106                 return -ENXIO;
 107         if (cc == 1)
 108                 return -EIO;
 109         return 0;
 110 }
 111
 112 /*
 113  * Copy a 4kB page of main memory to an expanded memory page
 114  * Arguments
 115  *           page_addr:    address of source page
 116  *           xpage_index:  index of expandeded memory page
 117  * Return value
 118  *           0:            if operation succeeds
 119  *           -EIO:         if pgout failed
 120  *           -ENXIO:       if xpram has vanished
 121  */
 122 static long xpram_page_out (unsigned long page_addr, unsigned int xpage_index)
 123 {
 124         int cc = 2;     /* return unused cc 2 if pgin traps */
 125
 126         asm volatile(
 127                 "       .insn   rre,0xb22f0000,%1,%2\n"  /* pgout %1,%2 */
 128                 "0:     ipm     %0\n"
 129                 "       srl     %0,28\n"
 130                 "1:\n"
 131                 EX_TABLE(0b,1b)
 132                 : "+d" (cc) : "a" (__pa(page_addr)), "d" (xpage_index) : "cc");
 133         if (cc == 3)
 134                 return -ENXIO;
 135         if (cc == 2)
 136                 return -ENXIO;
 137         if (cc == 1)
 138                 return -EIO;
 139         return 0;
 140 }
 141
 142 /*
 143  * Check if xpram is available.
 144  */
 145 static int xpram_present(void)
 146 {
 147         unsigned long mem_page;
 148         int rc;
 149
 150         mem_page = (unsigned long) __get_free_page(GFP_KERNEL);
 151         if (!mem_page)
 152                 return -ENOMEM;
 153         rc = xpram_page_in(mem_page, 0);
 154         free_page(mem_page);
 155         return rc ? -ENXIO : 0;
 156 }
 157
 158 /*
 159  * Return index of the last available xpram page.
 160  */
 161 static unsigned long xpram_highest_page_index(void)
 162 {
 163         unsigned int page_index, add_bit;
 164         unsigned long mem_page;
 165
 166         mem_page = (unsigned long) __get_free_page(GFP_KERNEL);
 167         if (!mem_page)
 168                 return 0;
 169
 170         page_index = 0;
 171         add_bit = 1ULL << (sizeof(unsigned int)*8 - 1);
 172         while (add_bit > 0) {
 173                 if (xpram_page_in(mem_page, page_index | add_bit) == 0)
 174                         page_index |= add_bit;
 175                 add_bit >>= 1;
 176         }
 177
 178         free_page (mem_page);
 179
 180         return page_index;
 181 }
 182
 183 /*
 184  * Block device make request function.
 185  */
 186 static int xpram_make_request(struct request_queue *q, struct bio *bio)
 187 {
 188         xpram_device_t *xdev = bio->bi_bdev->bd_disk->private_data;
 189         struct bio_vec *bvec;
 190         unsigned int index;
 191         unsigned long page_addr;
 192         unsigned long bytes;
 193         int i;
 194
 195         if ((bio->bi_sector & 7) != 0 || (bio->bi_size & 4095) != 0)
 196                 /* Request is not page-aligned. */
 197                 goto fail;
 198         if ((bio->bi_size >> 12) > xdev->size)
 199                 /* Request size is no page-aligned. */
 200                 goto fail;
 201         if ((bio->bi_sector >> 3) > 0xffffffffU - xdev->offset)
 202                 goto fail;
 203         index = (bio->bi_sector >> 3) + xdev->offset;
 204         bio_for_each_segment(bvec, bio, i) {
 205                 page_addr = (unsigned long)
 206                         kmap(bvec->bv_page) + bvec->bv_offset;
 207                 bytes = bvec->bv_len;
 208                 if ((page_addr & 4095) != 0 || (bytes & 4095) != 0)
 209                         /* More paranoia. */
 210                         goto fail;
 211                 while (bytes > 0) {
 212                         if (bio_data_dir(bio) == READ) {
 213                                 if (xpram_page_in(page_addr, index) != 0)
 214                                         goto fail;
 215                         } else {
 216                                 if (xpram_page_out(page_addr, index) != 0)
 217                                         goto fail;
 218                         }
 219                         page_addr += 4096;
 220                         bytes -= 4096;
 221                         index++;
 222                 }
 223         }
 224         set_bit(BIO_UPTODATE, &bio->bi_flags);
 225         bio_endio(bio, 0);
 226         return 0;
 227 fail:
 228         bio_io_error(bio);
 229         return 0;
 230 }
 231
 232 static int xpram_getgeo(struct block_device *bdev, struct hd_geometry *geo)
 233 {
 234         unsigned long size;
 235
 236         /*
 237          * get geometry: we have to fake one...  trim the size to a
 238          * multiple of 64 (32k): tell we have 16 sectors, 4 heads,
 239          * whatever cylinders. Tell also that data starts at sector. 4.
 240          */
 241         size = (xpram_pages * 8) & ~0x3f;
 242         geo->cylinders = size >> 6;
 243         geo->heads = 4;
 244         geo->sectors = 16;
 245         geo->start = 4;
 246         return 0;
 247 }
 248
 249 static struct block_device_operations xpram_devops =
 250 {
 251         .owner  = THIS_MODULE,
 252         .getgeo = xpram_getgeo,
 253 };
 254
 255 /*
 256  * Setup xpram_sizes array.
 257  */
 258 static int __init xpram_setup_sizes(unsigned long pages)
 259 {
 260         unsigned long mem_needed;
 261         unsigned long mem_auto;
 262         unsigned long long size;
 263         int mem_auto_no;
 264         int i;
 265
 266         /* Check number of devices. */
 267         if (devs <= 0 || devs > XPRAM_MAX_DEVS) {
 268                 pr_err("%d is not a valid number of XPRAM devices\n",devs);
 269                 return -EINVAL;
 270         }
 271         xpram_devs = devs;
 272
 273         /*
 274          * Copy sizes array to xpram_sizes and align partition
 275          * sizes to page boundary.
 276          */
 277         mem_needed = 0;
 278         mem_auto_no = 0;
 279         for (i = 0; i < xpram_devs; i++) {
 280                 if (sizes[i]) {
 281                         size = simple_strtoull(sizes[i], &sizes[i], 0);
 282                         switch (sizes[i][0]) {
 283                         case 'g':
 284                         case 'G':
 285                                 size <<= 20;
 286                                 break;
 287                         case 'm':
 288                         case 'M':
 289                                 size <<= 10;
 290                         }
 291                         xpram_sizes[i] = (size + 3) & -4UL;
 292                 }
 293                 if (xpram_sizes[i])
 294                         mem_needed += xpram_sizes[i];
 295                 else
 296                         mem_auto_no++;
 297         }
 298
 299         pr_info("  number of devices (partitions): %d \n", xpram_devs);
 300         for (i = 0; i < xpram_devs; i++) {
 301                 if (xpram_sizes[i])
 302                         pr_info("  size of partition %d: %u kB\n",
 303                                 i, xpram_sizes[i]);
 304                 else
 305                         pr_info("  size of partition %d to be set "
 306                                 "automatically\n",i);
 307         }
 308         pr_info("  memory needed (for sized partitions): %lu kB\n",
 309                 mem_needed);
 310         pr_info("  partitions to be sized automatically: %d\n",
 311                 mem_auto_no);
 312
 313         if (mem_needed > pages * 4) {
 314                 pr_err("Not enough expanded memory available\n");
 315                 return -EINVAL;
 316         }
 317
 318         /*
 319          * partitioning:
 320          * xpram_sizes[i] != 0; partition i has size xpram_sizes[i] kB
 321          * else:             ; all partitions with zero xpram_sizes[i]
 322          *                     partition equally the remaining space
 323          */
 324         if (mem_auto_no) {
 325                 mem_auto = ((pages - mem_needed / 4) / mem_auto_no) * 4;
 326                 pr_info("  automatically determined "
 327                         "partition size: %lu kB\n", mem_auto);
 328                 for (i = 0; i < xpram_devs; i++)
 329                         if (xpram_sizes[i] == 0)
 330                                 xpram_sizes[i] = mem_auto;
 331         }
 332         return 0;
 333 }
 334
 335 static int __init xpram_setup_blkdev(void)
 336 {
 337         unsigned long offset;
 338         int i, rc = -ENOMEM;
 339
 340         for (i = 0; i < xpram_devs; i++) {
 341                 xpram_disks[i] = alloc_disk(1);
 342                 if (!xpram_disks[i])
 343                         goto out;
 344                 xpram_queues[i] = blk_alloc_queue(GFP_KERNEL);
 345                 if (!xpram_queues[i]) {
 346                         put_disk(xpram_disks[i]);
 347                         goto out;
 348                 }
 349                 blk_queue_make_request(xpram_queues[i], xpram_make_request);
 350                 blk_queue_logical_block_size(xpram_queues[i], 4096);
 351         }
 352
 353         /*
 354          * Register xpram major.
 355          */
 356         rc = register_blkdev(XPRAM_MAJOR, XPRAM_NAME);
 357         if (rc < 0)
 358                 goto out;
 359
 360         /*
 361          * Setup device structures.
 362          */
 363         offset = 0;
 364         for (i = 0; i < xpram_devs; i++) {
 365                 struct gendisk *disk = xpram_disks[i];
 366
 367                 xpram_devices[i].size = xpram_sizes[i] / 4;
 368                 xpram_devices[i].offset = offset;
 369                 offset += xpram_devices[i].size;
 370                 disk->major = XPRAM_MAJOR;
 371                 disk->first_minor = i;
 372                 disk->fops = &xpram_devops;
 373                 disk->private_data = &xpram_devices[i];
 374                 disk->queue = xpram_queues[i];
 375                 sprintf(disk->disk_name, "slram%d", i);
 376                 set_capacity(disk, xpram_sizes[i] << 1);
 377                 add_disk(disk);
 378         }
 379
 380         return 0;
 381 out:
 382         while (i--) {
 383                 blk_cleanup_queue(xpram_queues[i]);
 384                 put_disk(xpram_disks[i]);
 385         }
 386         return rc;
 387 }
 388
 389 /*
 390  * Save checksums for all partitions.
 391  */
 392 static int xpram_save_checksums(void)
 393 {
 394         unsigned long mem_page;
 395         int rc, i;
 396
 397         rc = 0;
 398         mem_page = (unsigned long) __get_free_page(GFP_KERNEL);
 399         if (!mem_page)
 400                 return -ENOMEM;
 401         for (i = 0; i < xpram_devs; i++) {
 402                 rc = xpram_page_in(mem_page, xpram_devices[i].offset);
 403                 if (rc)
 404                         goto fail;
 405                 xpram_devices[i].csum = csum_partial((const void *) mem_page,
 406                                                      PAGE_SIZE, 0);
 407         }
 408 fail:
 409         free_page(mem_page);
 410         return rc ? -ENXIO : 0;
 411 }
 412
 413 /*
 414  * Verify checksums for all partitions.
 415  */
 416 static int xpram_validate_checksums(void)
 417 {
 418         unsigned long mem_page;
 419         unsigned int csum;
 420         int rc, i;
 421
 422         rc = 0;
 423         mem_page = (unsigned long) __get_free_page(GFP_KERNEL);
 424         if (!mem_page)
 425                 return -ENOMEM;
 426         for (i = 0; i < xpram_devs; i++) {
 427                 rc = xpram_page_in(mem_page, xpram_devices[i].offset);
 428                 if (rc)
 429                         goto fail;
 430                 csum = csum_partial((const void *) mem_page, PAGE_SIZE, 0);
 431                 if (xpram_devices[i].csum != csum) {
 432                         rc = -EINVAL;
 433                         goto fail;
 434                 }
 435         }
 436 fail:
 437         free_page(mem_page);
 438         return rc ? -ENXIO : 0;
 439 }
 440
 441 /*
 442  * Resume failed: Print error message and call panic.
 443  */
 444 static void xpram_resume_error(const char *message)
 445 {
 446         pr_err("Resuming the system failed: %s\n", message);
 447         panic("xpram resume error\n");
 448 }
 449
 450 /*
 451  * Check if xpram setup changed between suspend and resume.
 452  */
 453 static int xpram_restore(struct device *dev)
 454 {
 455         if (!xpram_pages)
 456                 return 0;
 457         if (xpram_present() != 0)
 458                 xpram_resume_error("xpram disappeared");
 459         if (xpram_pages != xpram_highest_page_index() + 1)
 460                 xpram_resume_error("Size of xpram changed");
 461         if (xpram_validate_checksums())
 462                 xpram_resume_error("Data of xpram changed");
 463         return 0;
 464 }
 465
 466 /*
 467  * Save necessary state in suspend.
 468  */
 469 static int xpram_freeze(struct device *dev)
 470 {
 471         return xpram_save_checksums();
 472 }
 473
 474 static struct dev_pm_ops xpram_pm_ops = {
 475         .freeze         = xpram_freeze,
 476         .restore        = xpram_restore,
 477 };
 478
 479 static struct platform_driver xpram_pdrv = {
 480         .driver = {
 481                 .name   = XPRAM_NAME,
 482                 .owner  = THIS_MODULE,
 483                 .pm     = &xpram_pm_ops,
 484         },
 485 };
 486
 487 static struct platform_device *xpram_pdev;
 488
 489 /*
 490  * Finally, the init/exit functions.
 491  */
 492 static void __exit xpram_exit(void)
 493 {
 494         int i;
 495         for (i = 0; i < xpram_devs; i++) {
 496                 del_gendisk(xpram_disks[i]);
 497                 blk_cleanup_queue(xpram_queues[i]);
 498                 put_disk(xpram_disks[i]);
 499         }
 500         unregister_blkdev(XPRAM_MAJOR, XPRAM_NAME);
 501         platform_device_unregister(xpram_pdev);
 502         platform_driver_unregister(&xpram_pdrv);
 503 }
 504
 505 static int __init xpram_init(void)
 506 {
 507         int rc;
 508
 509         /* Find out size of expanded memory. */
 510         if (xpram_present() != 0) {
 511                 pr_err("No expanded memory available\n");
 512                 return -ENODEV;
 513         }
 514         xpram_pages = xpram_highest_page_index() + 1;
 515         pr_info("  %u pages expanded memory found (%lu KB).\n",
 516                 xpram_pages, (unsigned long) xpram_pages*4);
 517         rc = xpram_setup_sizes(xpram_pages);
 518         if (rc)
 519                 return rc;
 520         rc = platform_driver_register(&xpram_pdrv);
 521         if (rc)
 522                 return rc;
 523         xpram_pdev = platform_device_register_simple(XPRAM_NAME, -1, NULL, 0);
 524         if (IS_ERR(xpram_pdev)) {
 525                 rc = PTR_ERR(xpram_pdev);
 526                 goto fail_platform_driver_unregister;
 527         }
 528         rc = xpram_setup_blkdev();
 529         if (rc)
 530                 goto fail_platform_device_unregister;
 531         return 0;
 532
 533 fail_platform_device_unregister:
 534         platform_device_unregister(xpram_pdev);
 535 fail_platform_driver_unregister:
 536         platform_driver_unregister(&xpram_pdrv);
 537         return rc;
 538 }
 539
 540 module_init(xpram_init);
 541 module_exit(xpram_exit);