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 #include <linux/module.h>
  29 #include <linux/moduleparam.h>
  30 #include <linux/ctype.h>  /* isdigit, isxdigit */
  31 #include <linux/errno.h>
  32 #include <linux/init.h>
  33 #include <linux/slab.h>
  34 #include <linux/blkdev.h>
  35 #include <linux/blkpg.h>
  36 #include <linux/hdreg.h>  /* HDIO_GETGEO */
  37 #include <linux/sysdev.h>
  38 #include <linux/bio.h>
  39 #include <asm/uaccess.h>
  40
  41 #define XPRAM_NAME      "xpram"
  42 #define XPRAM_DEVS      1       /* one partition */
  43 #define XPRAM_MAX_DEVS  32      /* maximal number of devices (partitions) */
  44
  45 #define PRINT_DEBUG(x...)       printk(KERN_DEBUG XPRAM_NAME " debug:" x)
  46 #define PRINT_INFO(x...)        printk(KERN_INFO XPRAM_NAME " info:" x)
  47 #define PRINT_WARN(x...)        printk(KERN_WARNING XPRAM_NAME " warning:" x)
  48 #define PRINT_ERR(x...)         printk(KERN_ERR XPRAM_NAME " error:" x)
  49
  50
  51 typedef struct {
  52         unsigned int    size;           /* size of xpram segment in pages */
  53         unsigned int    offset;         /* start page of xpram segment */
  54 } xpram_device_t;
  55
  56 static xpram_device_t xpram_devices[XPRAM_MAX_DEVS];
  57 static unsigned int xpram_sizes[XPRAM_MAX_DEVS];
  58 static struct gendisk *xpram_disks[XPRAM_MAX_DEVS];
  59 static unsigned int xpram_pages;
  60 static int xpram_devs;
  61
  62 /*
  63  * Parameter parsing functions.
  64  */
  65 static int __initdata devs = XPRAM_DEVS;
  66 static char __initdata *sizes[XPRAM_MAX_DEVS];
  67
  68 module_param(devs, int, 0);
  69 module_param_array(sizes, charp, NULL, 0);
  70
  71 MODULE_PARM_DESC(devs, "number of devices (\"partitions\"), " \
  72                  "the default is " __MODULE_STRING(XPRAM_DEVS) "\n");
  73 MODULE_PARM_DESC(sizes, "list of device (partition) sizes " \
  74                  "the defaults are 0s \n" \
  75                  "All devices with size 0 equally partition the "
  76                  "remaining space on the expanded strorage not "
  77                  "claimed by explicit sizes\n");
  78 MODULE_LICENSE("GPL");
  79
  80 /*
  81  * Copy expanded memory page (4kB) into main memory
  82  * Arguments
  83  *           page_addr:    address of target page
  84  *           xpage_index:  index of expandeded memory page
  85  * Return value
  86  *           0:            if operation succeeds
  87  *           -EIO:         if pgin failed
  88  *           -ENXIO:       if xpram has vanished
  89  */
  90 static int xpram_page_in (unsigned long page_addr, unsigned int xpage_index)
  91 {
  92         int cc;
  93
  94         __asm__ __volatile__ (
  95                 "   lhi   %0,2\n"  /* return unused cc 2 if pgin traps */
  96                 "   .insn rre,0xb22e0000,%1,%2\n"  /* pgin %1,%2 */
  97                 "0: ipm   %0\n"
  98                 "   srl   %0,28\n"
  99                 "1:\n"
 100 #ifndef CONFIG_64BIT
 101                 ".section __ex_table,\"a\"\n"
 102                 "   .align 4\n"
 103                 "   .long  0b,1b\n"
 104                 ".previous"
 105 #else
 106                 ".section __ex_table,\"a\"\n"
 107                 "   .align 8\n"
 108                 "   .quad 0b,1b\n"
 109                 ".previous"
 110 #endif
 111                 : "=&d" (cc)
 112                 : "a" (__pa(page_addr)), "a" (xpage_index)
 113                 : "cc" );
 114         if (cc == 3)
 115                 return -ENXIO;
 116         if (cc == 2) {
 117                 PRINT_ERR("expanded storage lost!\n");
 118                 return -ENXIO;
 119         }
 120         if (cc == 1) {
 121                 PRINT_ERR("page in failed for page index %u.\n",
 122                           xpage_index);
 123                 return -EIO;
 124         }
 125         return 0;
 126 }
 127
 128 /*
 129  * Copy a 4kB page of main memory to an expanded memory page
 130  * Arguments
 131  *           page_addr:    address of source page
 132  *           xpage_index:  index of expandeded memory page
 133  * Return value
 134  *           0:            if operation succeeds
 135  *           -EIO:         if pgout failed
 136  *           -ENXIO:       if xpram has vanished
 137  */
 138 static long xpram_page_out (unsigned long page_addr, unsigned int xpage_index)
 139 {
 140         int cc;
 141
 142         __asm__ __volatile__ (
 143                 "   lhi   %0,2\n"  /* return unused cc 2 if pgout traps */
 144                 "   .insn rre,0xb22f0000,%1,%2\n"  /* pgout %1,%2 */
 145                 "0: ipm   %0\n"
 146                 "   srl   %0,28\n"
 147                 "1:\n"
 148 #ifndef CONFIG_64BIT
 149                 ".section __ex_table,\"a\"\n"
 150                 "   .align 4\n"
 151                 "   .long  0b,1b\n"
 152                 ".previous"
 153 #else
 154                 ".section __ex_table,\"a\"\n"
 155                 "   .align 8\n"
 156                 "   .quad 0b,1b\n"
 157                 ".previous"
 158 #endif
 159                 : "=&d" (cc)
 160                 : "a" (__pa(page_addr)), "a" (xpage_index)
 161                 : "cc" );
 162         if (cc == 3)
 163                 return -ENXIO;
 164         if (cc == 2) {
 165                 PRINT_ERR("expanded storage lost!\n");
 166                 return -ENXIO;
 167         }
 168         if (cc == 1) {
 169                 PRINT_ERR("page out failed for page index %u.\n",
 170                           xpage_index);
 171                 return -EIO;
 172         }
 173         return 0;
 174 }
 175
 176 /*
 177  * Check if xpram is available.
 178  */
 179 static int __init xpram_present(void)
 180 {
 181         unsigned long mem_page;
 182         int rc;
 183
 184         mem_page = (unsigned long) __get_free_page(GFP_KERNEL);
 185         if (!mem_page)
 186                 return -ENOMEM;
 187         rc = xpram_page_in(mem_page, 0);
 188         free_page(mem_page);
 189         return rc ? -ENXIO : 0;
 190 }
 191
 192 /*
 193  * Return index of the last available xpram page.
 194  */
 195 static unsigned long __init xpram_highest_page_index(void)
 196 {
 197         unsigned int page_index, add_bit;
 198         unsigned long mem_page;
 199
 200         mem_page = (unsigned long) __get_free_page(GFP_KERNEL);
 201         if (!mem_page)
 202                 return 0;
 203
 204         page_index = 0;
 205         add_bit = 1ULL << (sizeof(unsigned int)*8 - 1);
 206         while (add_bit > 0) {
 207                 if (xpram_page_in(mem_page, page_index | add_bit) == 0)
 208                         page_index |= add_bit;
 209                 add_bit >>= 1;
 210         }
 211
 212         free_page (mem_page);
 213
 214         return page_index;
 215 }
 216
 217 /*
 218  * Block device make request function.
 219  */
 220 static int xpram_make_request(request_queue_t *q, struct bio *bio)
 221 {
 222         xpram_device_t *xdev = bio->bi_bdev->bd_disk->private_data;
 223         struct bio_vec *bvec;
 224         unsigned int index;
 225         unsigned long page_addr;
 226         unsigned long bytes;
 227         int i;
 228
 229         if ((bio->bi_sector & 7) != 0 || (bio->bi_size & 4095) != 0)
 230                 /* Request is not page-aligned. */
 231                 goto fail;
 232         if ((bio->bi_size >> 12) > xdev->size)
 233                 /* Request size is no page-aligned. */
 234                 goto fail;
 235         if ((bio->bi_sector >> 3) > 0xffffffffU - xdev->offset)
 236                 goto fail;
 237         index = (bio->bi_sector >> 3) + xdev->offset;
 238         bio_for_each_segment(bvec, bio, i) {
 239                 page_addr = (unsigned long)
 240                         kmap(bvec->bv_page) + bvec->bv_offset;
 241                 bytes = bvec->bv_len;
 242                 if ((page_addr & 4095) != 0 || (bytes & 4095) != 0)
 243                         /* More paranoia. */
 244                         goto fail;
 245                 while (bytes > 0) {
 246                         if (bio_data_dir(bio) == READ) {
 247                                 if (xpram_page_in(page_addr, index) != 0)
 248                                         goto fail;
 249                         } else {
 250                                 if (xpram_page_out(page_addr, index) != 0)
 251                                         goto fail;
 252                         }
 253                         page_addr += 4096;
 254                         bytes -= 4096;
 255                         index++;
 256                 }
 257         }
 258         set_bit(BIO_UPTODATE, &bio->bi_flags);
 259         bytes = bio->bi_size;
 260         bio->bi_size = 0;
 261         bio->bi_end_io(bio, bytes, 0);
 262         return 0;
 263 fail:
 264         bio_io_error(bio, bio->bi_size);
 265         return 0;
 266 }
 267
 268 static int xpram_getgeo(struct block_device *bdev, struct hd_geometry *geo)
 269 {
 270         unsigned long size;
 271
 272         /*
 273          * get geometry: we have to fake one...  trim the size to a
 274          * multiple of 64 (32k): tell we have 16 sectors, 4 heads,
 275          * whatever cylinders. Tell also that data starts at sector. 4.
 276          */
 277         size = (xpram_pages * 8) & ~0x3f;
 278         geo->cylinders = size >> 6;
 279         geo->heads = 4;
 280         geo->sectors = 16;
 281         geo->start = 4;
 282         return 0;
 283 }
 284
 285 static struct block_device_operations xpram_devops =
 286 {
 287         .owner  = THIS_MODULE,
 288         .getgeo = xpram_getgeo,
 289 };
 290
 291 /*
 292  * Setup xpram_sizes array.
 293  */
 294 static int __init xpram_setup_sizes(unsigned long pages)
 295 {
 296         unsigned long mem_needed;
 297         unsigned long mem_auto;
 298         unsigned long long size;
 299         int mem_auto_no;
 300         int i;
 301
 302         /* Check number of devices. */
 303         if (devs <= 0 || devs > XPRAM_MAX_DEVS) {
 304                 PRINT_ERR("invalid number %d of devices\n",devs);
 305                 return -EINVAL;
 306         }
 307         xpram_devs = devs;
 308
 309         /*
 310          * Copy sizes array to xpram_sizes and align partition
 311          * sizes to page boundary.
 312          */
 313         mem_needed = 0;
 314         mem_auto_no = 0;
 315         for (i = 0; i < xpram_devs; i++) {
 316                 if (sizes[i]) {
 317                         size = simple_strtoull(sizes[i], &sizes[i], 0);
 318                         switch (sizes[i][0]) {
 319                         case 'g':
 320                         case 'G':
 321                                 size <<= 20;
 322                                 break;
 323                         case 'm':
 324                         case 'M':
 325                                 size <<= 10;
 326                         }
 327                         xpram_sizes[i] = (size + 3) & -4UL;
 328                 }
 329                 if (xpram_sizes[i])
 330                         mem_needed += xpram_sizes[i];
 331                 else
 332                         mem_auto_no++;
 333         }
 334
 335         PRINT_INFO("  number of devices (partitions): %d \n", xpram_devs);
 336         for (i = 0; i < xpram_devs; i++) {
 337                 if (xpram_sizes[i])
 338                         PRINT_INFO("  size of partition %d: %u kB\n",
 339                                    i, xpram_sizes[i]);
 340                 else
 341                         PRINT_INFO("  size of partition %d to be set "
 342                                    "automatically\n",i);
 343         }
 344         PRINT_DEBUG("  memory needed (for sized partitions): %lu kB\n",
 345                     mem_needed);
 346         PRINT_DEBUG("  partitions to be sized automatically: %d\n",
 347                     mem_auto_no);
 348
 349         if (mem_needed > pages * 4) {
 350                 PRINT_ERR("Not enough expanded memory available\n");
 351                 return -EINVAL;
 352         }
 353
 354         /*
 355          * partitioning:
 356          * xpram_sizes[i] != 0; partition i has size xpram_sizes[i] kB
 357          * else:             ; all partitions with zero xpram_sizes[i]
 358          *                     partition equally the remaining space
 359          */
 360         if (mem_auto_no) {
 361                 mem_auto = ((pages - mem_needed / 4) / mem_auto_no) * 4;
 362                 PRINT_INFO("  automatically determined "
 363                            "partition size: %lu kB\n", mem_auto);
 364                 for (i = 0; i < xpram_devs; i++)
 365                         if (xpram_sizes[i] == 0)
 366                                 xpram_sizes[i] = mem_auto;
 367         }
 368         return 0;
 369 }
 370
 371 static struct request_queue *xpram_queue;
 372
 373 static int __init xpram_setup_blkdev(void)
 374 {
 375         unsigned long offset;
 376         int i, rc = -ENOMEM;
 377
 378         for (i = 0; i < xpram_devs; i++) {
 379                 struct gendisk *disk = alloc_disk(1);
 380                 if (!disk)
 381                         goto out;
 382                 xpram_disks[i] = disk;
 383         }
 384
 385         /*
 386          * Register xpram major.
 387          */
 388         rc = register_blkdev(XPRAM_MAJOR, XPRAM_NAME);
 389         if (rc < 0)
 390                 goto out;
 391
 392         /*
 393          * Assign the other needed values: make request function, sizes and
 394          * hardsect size. All the minor devices feature the same value.
 395          */
 396         xpram_queue = blk_alloc_queue(GFP_KERNEL);
 397         if (!xpram_queue) {
 398                 rc = -ENOMEM;
 399                 goto out_unreg;
 400         }
 401         blk_queue_make_request(xpram_queue, xpram_make_request);
 402         blk_queue_hardsect_size(xpram_queue, 4096);
 403
 404         /*
 405          * Setup device structures.
 406          */
 407         offset = 0;
 408         for (i = 0; i < xpram_devs; i++) {
 409                 struct gendisk *disk = xpram_disks[i];
 410
 411                 xpram_devices[i].size = xpram_sizes[i] / 4;
 412                 xpram_devices[i].offset = offset;
 413                 offset += xpram_devices[i].size;
 414                 disk->major = XPRAM_MAJOR;
 415                 disk->first_minor = i;
 416                 disk->fops = &xpram_devops;
 417                 disk->private_data = &xpram_devices[i];
 418                 disk->queue = xpram_queue;
 419                 sprintf(disk->disk_name, "slram%d", i);
 420                 set_capacity(disk, xpram_sizes[i] << 1);
 421                 add_disk(disk);
 422         }
 423
 424         return 0;
 425 out_unreg:
 426         unregister_blkdev(XPRAM_MAJOR, XPRAM_NAME);
 427 out:
 428         while (i--)
 429                 put_disk(xpram_disks[i]);
 430         return rc;
 431 }
 432
 433 /*
 434  * Finally, the init/exit functions.
 435  */
 436 static void __exit xpram_exit(void)
 437 {
 438         int i;
 439         for (i = 0; i < xpram_devs; i++) {
 440                 del_gendisk(xpram_disks[i]);
 441                 put_disk(xpram_disks[i]);
 442         }
 443         unregister_blkdev(XPRAM_MAJOR, XPRAM_NAME);
 444         blk_cleanup_queue(xpram_queue);
 445 }
 446
 447 static int __init xpram_init(void)
 448 {
 449         int rc;
 450
 451         /* Find out size of expanded memory. */
 452         if (xpram_present() != 0) {
 453                 PRINT_WARN("No expanded memory available\n");
 454                 return -ENODEV;
 455         }
 456         xpram_pages = xpram_highest_page_index() + 1;
 457         PRINT_INFO("  %u pages expanded memory found (%lu KB).\n",
 458                    xpram_pages, (unsigned long) xpram_pages*4);
 459         rc = xpram_setup_sizes(xpram_pages);
 460         if (rc)
 461                 return rc;
 462         return xpram_setup_blkdev();
 463 }
 464
 465 module_init(xpram_init);
 466 module_exit(xpram_exit);