drivers/crypto/nx/nx-842.c

   1 /*
   2  * Driver for IBM Power 842 compression accelerator
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  17  *
  18  * Copyright (C) IBM Corporation, 2012
  19  *
  20  * Authors: Robert Jennings <rcj@linux.vnet.ibm.com>
  21  *          Seth Jennings <sjenning@linux.vnet.ibm.com>
  22  */
  23
  24 #include <linux/kernel.h>
  25 #include <linux/module.h>
  26 #include <linux/nx842.h>
  27 #include <linux/of.h>
  28 #include <linux/slab.h>
  29
  30 #include <asm/page.h>
  31 #include <asm/vio.h>
  32
  33 #include "nx_csbcpb.h" /* struct nx_csbcpb */
  34
  35 #define MODULE_NAME "nx-compress"
  36 MODULE_LICENSE("GPL");
  37 MODULE_AUTHOR("Robert Jennings <rcj@linux.vnet.ibm.com>");
  38 MODULE_DESCRIPTION("842 H/W Compression driver for IBM Power processors");
  39
  40 #define SHIFT_4K 12
  41 #define SHIFT_64K 16
  42 #define SIZE_4K (1UL << SHIFT_4K)
  43 #define SIZE_64K (1UL << SHIFT_64K)
  44
  45 /* IO buffer must be 128 byte aligned */
  46 #define IO_BUFFER_ALIGN 128
  47
  48 struct nx842_header {
  49         int blocks_nr; /* number of compressed blocks */
  50         int offset; /* offset of the first block (from beginning of header) */
  51         int sizes[0]; /* size of compressed blocks */
  52 };
  53
  54 static inline int nx842_header_size(const struct nx842_header *hdr)
  55 {
  56         return sizeof(struct nx842_header) +
  57                         hdr->blocks_nr * sizeof(hdr->sizes[0]);
  58 }
  59
  60 /* Macros for fields within nx_csbcpb */
  61 /* Check the valid bit within the csbcpb valid field */
  62 #define NX842_CSBCBP_VALID_CHK(x) (x & BIT_MASK(7))
  63
  64 /* CE macros operate on the completion_extension field bits in the csbcpb.
  65  * CE0 0=full completion, 1=partial completion
  66  * CE1 0=CE0 indicates completion, 1=termination (output may be modified)
  67  * CE2 0=processed_bytes is source bytes, 1=processed_bytes is target bytes */
  68 #define NX842_CSBCPB_CE0(x)     (x & BIT_MASK(7))
  69 #define NX842_CSBCPB_CE1(x)     (x & BIT_MASK(6))
  70 #define NX842_CSBCPB_CE2(x)     (x & BIT_MASK(5))
  71
  72 /* The NX unit accepts data only on 4K page boundaries */
  73 #define NX842_HW_PAGE_SHIFT     SHIFT_4K
  74 #define NX842_HW_PAGE_SIZE      (ASM_CONST(1) << NX842_HW_PAGE_SHIFT)
  75 #define NX842_HW_PAGE_MASK      (~(NX842_HW_PAGE_SIZE-1))
  76
  77 enum nx842_status {
  78         UNAVAILABLE,
  79         AVAILABLE
  80 };
  81
  82 struct ibm_nx842_counters {
  83         atomic64_t comp_complete;
  84         atomic64_t comp_failed;
  85         atomic64_t decomp_complete;
  86         atomic64_t decomp_failed;
  87         atomic64_t swdecomp;
  88         atomic64_t comp_times[32];
  89         atomic64_t decomp_times[32];
  90 };
  91
  92 static struct nx842_devdata {
  93         struct vio_dev *vdev;
  94         struct device *dev;
  95         struct ibm_nx842_counters *counters;
  96         unsigned int max_sg_len;
  97         unsigned int max_sync_size;
  98         unsigned int max_sync_sg;
  99         enum nx842_status status;
 100 } __rcu *devdata;
 101 static DEFINE_SPINLOCK(devdata_mutex);
 102
 103 #define NX842_COUNTER_INC(_x) \
 104 static inline void nx842_inc_##_x( \
 105         const struct nx842_devdata *dev) { \
 106         if (dev) \
 107                 atomic64_inc(&dev->counters->_x); \
 108 }
 109 NX842_COUNTER_INC(comp_complete);
 110 NX842_COUNTER_INC(comp_failed);
 111 NX842_COUNTER_INC(decomp_complete);
 112 NX842_COUNTER_INC(decomp_failed);
 113 NX842_COUNTER_INC(swdecomp);
 114
 115 #define NX842_HIST_SLOTS 16
 116
 117 static void ibm_nx842_incr_hist(atomic64_t *times, unsigned int time)
 118 {
 119         int bucket = fls(time);
 120
 121         if (bucket)
 122                 bucket = min((NX842_HIST_SLOTS - 1), bucket - 1);
 123
 124         atomic64_inc(&times[bucket]);
 125 }
 126
 127 /* NX unit operation flags */
 128 #define NX842_OP_COMPRESS       0x0
 129 #define NX842_OP_CRC            0x1
 130 #define NX842_OP_DECOMPRESS     0x2
 131 #define NX842_OP_COMPRESS_CRC   (NX842_OP_COMPRESS | NX842_OP_CRC)
 132 #define NX842_OP_DECOMPRESS_CRC (NX842_OP_DECOMPRESS | NX842_OP_CRC)
 133 #define NX842_OP_ASYNC          (1<<23)
 134 #define NX842_OP_NOTIFY         (1<<22)
 135 #define NX842_OP_NOTIFY_INT(x)  ((x & 0xff)<<8)
 136
 137 static unsigned long nx842_get_desired_dma(struct vio_dev *viodev)
 138 {
 139         /* No use of DMA mappings within the driver. */
 140         return 0;
 141 }
 142
 143 struct nx842_slentry {
 144         unsigned long ptr; /* Real address (use __pa()) */
 145         unsigned long len;
 146 };
 147
 148 /* pHyp scatterlist entry */
 149 struct nx842_scatterlist {
 150         int entry_nr; /* number of slentries */
 151         struct nx842_slentry *entries; /* ptr to array of slentries */
 152 };
 153
 154 /* Does not include sizeof(entry_nr) in the size */
 155 static inline unsigned long nx842_get_scatterlist_size(
 156                                 struct nx842_scatterlist *sl)
 157 {
 158         return sl->entry_nr * sizeof(struct nx842_slentry);
 159 }
 160
 161 static inline unsigned long nx842_get_pa(void *addr)
 162 {
 163         if (is_vmalloc_addr(addr))
 164                 return page_to_phys(vmalloc_to_page(addr))
 165                        + offset_in_page(addr);
 166         else
 167                 return __pa(addr);
 168 }
 169
 170 static int nx842_build_scatterlist(unsigned long buf, int len,
 171                         struct nx842_scatterlist *sl)
 172 {
 173         unsigned long nextpage;
 174         struct nx842_slentry *entry;
 175
 176         sl->entry_nr = 0;
 177
 178         entry = sl->entries;
 179         while (len) {
 180                 entry->ptr = nx842_get_pa((void *)buf);
 181                 nextpage = ALIGN(buf + 1, NX842_HW_PAGE_SIZE);
 182                 if (nextpage < buf + len) {
 183                         /* we aren't at the end yet */
 184                         if (IS_ALIGNED(buf, NX842_HW_PAGE_SIZE))
 185                                 /* we are in the middle (or beginning) */
 186                                 entry->len = NX842_HW_PAGE_SIZE;
 187                         else
 188                                 /* we are at the beginning */
 189                                 entry->len = nextpage - buf;
 190                 } else {
 191                         /* at the end */
 192                         entry->len = len;
 193                 }
 194
 195                 len -= entry->len;
 196                 buf += entry->len;
 197                 sl->entry_nr++;
 198                 entry++;
 199         }
 200
 201         return 0;
 202 }
 203
 204 /*
 205  * Working memory for software decompression
 206  */
 207 struct sw842_fifo {
 208         union {
 209                 char f8[256][8];
 210                 char f4[512][4];
 211         };
 212         char f2[256][2];
 213         unsigned char f84_full;
 214         unsigned char f2_full;
 215         unsigned char f8_count;
 216         unsigned char f2_count;
 217         unsigned int f4_count;
 218 };
 219
 220 /*
 221  * Working memory for crypto API
 222  */
 223 struct nx842_workmem {
 224         char bounce[PAGE_SIZE]; /* bounce buffer for decompression input */
 225         union {
 226                 /* hardware working memory */
 227                 struct {
 228                         /* scatterlist */
 229                         char slin[SIZE_4K];
 230                         char slout[SIZE_4K];
 231                         /* coprocessor status/parameter block */
 232                         struct nx_csbcpb csbcpb;
 233                 };
 234                 /* software working memory */
 235                 struct sw842_fifo swfifo; /* software decompression fifo */
 236         };
 237 };
 238
 239 int nx842_get_workmem_size(void)
 240 {
 241         return sizeof(struct nx842_workmem) + NX842_HW_PAGE_SIZE;
 242 }
 243 EXPORT_SYMBOL_GPL(nx842_get_workmem_size);
 244
 245 int nx842_get_workmem_size_aligned(void)
 246 {
 247         return sizeof(struct nx842_workmem);
 248 }
 249 EXPORT_SYMBOL_GPL(nx842_get_workmem_size_aligned);
 250
 251 static int nx842_validate_result(struct device *dev,
 252         struct cop_status_block *csb)
 253 {
 254         /* The csb must be valid after returning from vio_h_cop_sync */
 255         if (!NX842_CSBCBP_VALID_CHK(csb->valid)) {
 256                 dev_err(dev, "%s: cspcbp not valid upon completion.\n",
 257                                 __func__);
 258                 dev_dbg(dev, "valid:0x%02x cs:0x%02x cc:0x%02x ce:0x%02x\n",
 259                                 csb->valid,
 260                                 csb->crb_seq_number,
 261                                 csb->completion_code,
 262                                 csb->completion_extension);
 263                 dev_dbg(dev, "processed_bytes:%d address:0x%016lx\n",
 264                                 csb->processed_byte_count,
 265                                 (unsigned long)csb->address);
 266                 return -EIO;
 267         }
 268
 269         /* Check return values from the hardware in the CSB */
 270         switch (csb->completion_code) {
 271         case 0: /* Completed without error */
 272                 break;
 273         case 64: /* Target bytes > Source bytes during compression */
 274         case 13: /* Output buffer too small */
 275                 dev_dbg(dev, "%s: Compression output larger than input\n",
 276                                         __func__);
 277                 return -ENOSPC;
 278         case 66: /* Input data contains an illegal template field */
 279         case 67: /* Template indicates data past the end of the input stream */
 280                 dev_dbg(dev, "%s: Bad data for decompression (code:%d)\n",
 281                                         __func__, csb->completion_code);
 282                 return -EINVAL;
 283         default:
 284                 dev_dbg(dev, "%s: Unspecified error (code:%d)\n",
 285                                         __func__, csb->completion_code);
 286                 return -EIO;
 287         }
 288
 289         /* Hardware sanity check */
 290         if (!NX842_CSBCPB_CE2(csb->completion_extension)) {
 291                 dev_err(dev, "%s: No error returned by hardware, but "
 292                                 "data returned is unusable, contact support.\n"
 293                                 "(Additional info: csbcbp->processed bytes "
 294                                 "does not specify processed bytes for the "
 295                                 "target buffer.)\n", __func__);
 296                 return -EIO;
 297         }
 298
 299         return 0;
 300 }
 301
 302 /**
 303  * nx842_compress - Compress data using the 842 algorithm
 304  *
 305  * Compression provide by the NX842 coprocessor on IBM Power systems.
 306  * The input buffer is compressed and the result is stored in the
 307  * provided output buffer.
 308  *
 309  * Upon return from this function @outlen contains the length of the
 310  * compressed data.  If there is an error then @outlen will be 0 and an
 311  * error will be specified by the return code from this function.
 312  *
 313  * @in: Pointer to input buffer, must be page aligned
 314  * @inlen: Length of input buffer, must be PAGE_SIZE
 315  * @out: Pointer to output buffer
 316  * @outlen: Length of output buffer
 317  * @wrkmem: ptr to buffer for working memory, size determined by
 318  *          nx842_get_workmem_size()
 319  *
 320  * Returns:
 321  *   0          Success, output of length @outlen stored in the buffer at @out
 322  *   -ENOMEM    Unable to allocate internal buffers
 323  *   -ENOSPC    Output buffer is to small
 324  *   -EMSGSIZE  XXX Difficult to describe this limitation
 325  *   -EIO       Internal error
 326  *   -ENODEV    Hardware unavailable
 327  */
 328 int nx842_compress(const unsigned char *in, unsigned int inlen,
 329                        unsigned char *out, unsigned int *outlen, void *wmem)
 330 {
 331         struct nx842_header *hdr;
 332         struct nx842_devdata *local_devdata;
 333         struct device *dev = NULL;
 334         struct nx842_workmem *workmem;
 335         struct nx842_scatterlist slin, slout;
 336         struct nx_csbcpb *csbcpb;
 337         int ret = 0, max_sync_size, i, bytesleft, size, hdrsize;
 338         unsigned long inbuf, outbuf, padding;
 339         struct vio_pfo_op op = {
 340                 .done = NULL,
 341                 .handle = 0,
 342                 .timeout = 0,
 343         };
 344         unsigned long start_time = get_tb();
 345
 346         /*
 347          * Make sure input buffer is 64k page aligned.  This is assumed since
 348          * this driver is designed for page compression only (for now).  This
 349          * is very nice since we can now use direct DDE(s) for the input and
 350          * the alignment is guaranteed.
 351         */
 352         inbuf = (unsigned long)in;
 353         if (!IS_ALIGNED(inbuf, PAGE_SIZE) || inlen != PAGE_SIZE)
 354                 return -EINVAL;
 355
 356         rcu_read_lock();
 357         local_devdata = rcu_dereference(devdata);
 358         if (!local_devdata || !local_devdata->dev) {
 359                 rcu_read_unlock();
 360                 return -ENODEV;
 361         }
 362         max_sync_size = local_devdata->max_sync_size;
 363         dev = local_devdata->dev;
 364
 365         /* Create the header */
 366         hdr = (struct nx842_header *)out;
 367         hdr->blocks_nr = PAGE_SIZE / max_sync_size;
 368         hdrsize = nx842_header_size(hdr);
 369         outbuf = (unsigned long)out + hdrsize;
 370         bytesleft = *outlen - hdrsize;
 371
 372         /* Init scatterlist */
 373         workmem = (struct nx842_workmem *)ALIGN((unsigned long)wmem,
 374                 NX842_HW_PAGE_SIZE);
 375         slin.entries = (struct nx842_slentry *)workmem->slin;
 376         slout.entries = (struct nx842_slentry *)workmem->slout;
 377
 378         /* Init operation */
 379         op.flags = NX842_OP_COMPRESS;
 380         csbcpb = &workmem->csbcpb;
 381         memset(csbcpb, 0, sizeof(*csbcpb));
 382         op.csbcpb = nx842_get_pa(csbcpb);
 383         op.out = nx842_get_pa(slout.entries);
 384
 385         for (i = 0; i < hdr->blocks_nr; i++) {
 386                 /*
 387                  * Aligning the output blocks to 128 bytes does waste space,
 388                  * but it prevents the need for bounce buffers and memory
 389                  * copies.  It also simplifies the code a lot.  In the worst
 390                  * case (64k page, 4k max_sync_size), you lose up to
 391                  * (128*16)/64k = ~3% the compression factor. For 64k
 392                  * max_sync_size, the loss would be at most 128/64k = ~0.2%.
 393                  */
 394                 padding = ALIGN(outbuf, IO_BUFFER_ALIGN) - outbuf;
 395                 outbuf += padding;
 396                 bytesleft -= padding;
 397                 if (i == 0)
 398                         /* save offset into first block in header */
 399                         hdr->offset = padding + hdrsize;
 400
 401                 if (bytesleft <= 0) {
 402                         ret = -ENOSPC;
 403                         goto unlock;
 404                 }
 405
 406                 /*
 407                  * NOTE: If the default max_sync_size is changed from 4k
 408                  * to 64k, remove the "likely" case below, since a
 409                  * scatterlist will always be needed.
 410                  */
 411                 if (likely(max_sync_size == NX842_HW_PAGE_SIZE)) {
 412                         /* Create direct DDE */
 413                         op.in = nx842_get_pa((void *)inbuf);
 414                         op.inlen = max_sync_size;
 415
 416                 } else {
 417                         /* Create indirect DDE (scatterlist) */
 418                         nx842_build_scatterlist(inbuf, max_sync_size, &slin);
 419                         op.in = nx842_get_pa(slin.entries);
 420                         op.inlen = -nx842_get_scatterlist_size(&slin);
 421                 }
 422
 423                 /*
 424                  * If max_sync_size != NX842_HW_PAGE_SIZE, an indirect
 425                  * DDE is required for the outbuf.
 426                  * If max_sync_size == NX842_HW_PAGE_SIZE, outbuf must
 427                  * also be page aligned (1 in 128/4k=32 chance) in order
 428                  * to use a direct DDE.
 429                  * This is unlikely, just use an indirect DDE always.
 430                  */
 431                 nx842_build_scatterlist(outbuf,
 432                         min(bytesleft, max_sync_size), &slout);
 433                 /* op.out set before loop */
 434                 op.outlen = -nx842_get_scatterlist_size(&slout);
 435
 436                 /* Send request to pHyp */
 437                 ret = vio_h_cop_sync(local_devdata->vdev, &op);
 438
 439                 /* Check for pHyp error */
 440                 if (ret) {
 441                         dev_dbg(dev, "%s: vio_h_cop_sync error (ret=%d, hret=%ld)\n",
 442                                 __func__, ret, op.hcall_err);
 443                         ret = -EIO;
 444                         goto unlock;
 445                 }
 446
 447                 /* Check for hardware error */
 448                 ret = nx842_validate_result(dev, &csbcpb->csb);
 449                 if (ret && ret != -ENOSPC)
 450                         goto unlock;
 451
 452                 /* Handle incompressible data */
 453                 if (unlikely(ret == -ENOSPC)) {
 454                         if (bytesleft < max_sync_size) {
 455                                 /*
 456                                  * Not enough space left in the output buffer
 457                                  * to store uncompressed block
 458                                  */
 459                                 goto unlock;
 460                         } else {
 461                                 /* Store incompressible block */
 462                                 memcpy((void *)outbuf, (void *)inbuf,
 463                                         max_sync_size);
 464                                 hdr->sizes[i] = -max_sync_size;
 465                                 outbuf += max_sync_size;
 466                                 bytesleft -= max_sync_size;
 467                                 /* Reset ret, incompressible data handled */
 468                                 ret = 0;
 469                         }
 470                 } else {
 471                         /* Normal case, compression was successful */
 472                         size = csbcpb->csb.processed_byte_count;
 473                         dev_dbg(dev, "%s: processed_bytes=%d\n",
 474                                 __func__, size);
 475                         hdr->sizes[i] = size;
 476                         outbuf += size;
 477                         bytesleft -= size;
 478                 }
 479
 480                 inbuf += max_sync_size;
 481         }
 482
 483         *outlen = (unsigned int)(outbuf - (unsigned long)out);
 484
 485 unlock:
 486         if (ret)
 487                 nx842_inc_comp_failed(local_devdata);
 488         else {
 489                 nx842_inc_comp_complete(local_devdata);
 490                 ibm_nx842_incr_hist(local_devdata->counters->comp_times,
 491                         (get_tb() - start_time) / tb_ticks_per_usec);
 492         }
 493         rcu_read_unlock();
 494         return ret;
 495 }
 496 EXPORT_SYMBOL_GPL(nx842_compress);
 497
 498 static int sw842_decompress(const unsigned char *, int, unsigned char *, int *,
 499                         const void *);
 500
 501 /**
 502  * nx842_decompress - Decompress data using the 842 algorithm
 503  *
 504  * Decompression provide by the NX842 coprocessor on IBM Power systems.
 505  * The input buffer is decompressed and the result is stored in the
 506  * provided output buffer.  The size allocated to the output buffer is
 507  * provided by the caller of this function in @outlen.  Upon return from
 508  * this function @outlen contains the length of the decompressed data.
 509  * If there is an error then @outlen will be 0 and an error will be
 510  * specified by the return code from this function.
 511  *
 512  * @in: Pointer to input buffer, will use bounce buffer if not 128 byte
 513  *      aligned
 514  * @inlen: Length of input buffer
 515  * @out: Pointer to output buffer, must be page aligned
 516  * @outlen: Length of output buffer, must be PAGE_SIZE
 517  * @wrkmem: ptr to buffer for working memory, size determined by
 518  *          nx842_get_workmem_size()
 519  *
 520  * Returns:
 521  *   0          Success, output of length @outlen stored in the buffer at @out
 522  *   -ENODEV    Hardware decompression device is unavailable
 523  *   -ENOMEM    Unable to allocate internal buffers
 524  *   -ENOSPC    Output buffer is to small
 525  *   -EINVAL    Bad input data encountered when attempting decompress
 526  *   -EIO       Internal error
 527  */
 528 int nx842_decompress(const unsigned char *in, unsigned int inlen,
 529                          unsigned char *out, unsigned int *outlen, void *wmem)
 530 {
 531         struct nx842_header *hdr;
 532         struct nx842_devdata *local_devdata;
 533         struct device *dev = NULL;
 534         struct nx842_workmem *workmem;
 535         struct nx842_scatterlist slin, slout;
 536         struct nx_csbcpb *csbcpb;
 537         int ret = 0, i, size, max_sync_size;
 538         unsigned long inbuf, outbuf;
 539         struct vio_pfo_op op = {
 540                 .done = NULL,
 541                 .handle = 0,
 542                 .timeout = 0,
 543         };
 544         unsigned long start_time = get_tb();
 545
 546         /* Ensure page alignment and size */
 547         outbuf = (unsigned long)out;
 548         if (!IS_ALIGNED(outbuf, PAGE_SIZE) || *outlen != PAGE_SIZE)
 549                 return -EINVAL;
 550
 551         rcu_read_lock();
 552         local_devdata = rcu_dereference(devdata);
 553         if (local_devdata)
 554                 dev = local_devdata->dev;
 555
 556         /* Get header */
 557         hdr = (struct nx842_header *)in;
 558
 559         workmem = (struct nx842_workmem *)ALIGN((unsigned long)wmem,
 560                 NX842_HW_PAGE_SIZE);
 561
 562         inbuf = (unsigned long)in + hdr->offset;
 563         if (likely(!IS_ALIGNED(inbuf, IO_BUFFER_ALIGN))) {
 564                 /* Copy block(s) into bounce buffer for alignment */
 565                 memcpy(workmem->bounce, in + hdr->offset, inlen - hdr->offset);
 566                 inbuf = (unsigned long)workmem->bounce;
 567         }
 568
 569         /* Init scatterlist */
 570         slin.entries = (struct nx842_slentry *)workmem->slin;
 571         slout.entries = (struct nx842_slentry *)workmem->slout;
 572
 573         /* Init operation */
 574         op.flags = NX842_OP_DECOMPRESS;
 575         csbcpb = &workmem->csbcpb;
 576         memset(csbcpb, 0, sizeof(*csbcpb));
 577         op.csbcpb = nx842_get_pa(csbcpb);
 578
 579         /*
 580          * max_sync_size may have changed since compression,
 581          * so we can't read it from the device info. We need
 582          * to derive it from hdr->blocks_nr.
 583          */
 584         max_sync_size = PAGE_SIZE / hdr->blocks_nr;
 585
 586         for (i = 0; i < hdr->blocks_nr; i++) {
 587                 /* Skip padding */
 588                 inbuf = ALIGN(inbuf, IO_BUFFER_ALIGN);
 589
 590                 if (hdr->sizes[i] < 0) {
 591                         /* Negative sizes indicate uncompressed data blocks */
 592                         size = abs(hdr->sizes[i]);
 593                         memcpy((void *)outbuf, (void *)inbuf, size);
 594                         outbuf += size;
 595                         inbuf += size;
 596                         continue;
 597                 }
 598
 599                 if (!dev)
 600                         goto sw;
 601
 602                 /*
 603                  * The better the compression, the more likely the "likely"
 604                  * case becomes.
 605                  */
 606                 if (likely((inbuf & NX842_HW_PAGE_MASK) ==
 607                         ((inbuf + hdr->sizes[i] - 1) & NX842_HW_PAGE_MASK))) {
 608                         /* Create direct DDE */
 609                         op.in = nx842_get_pa((void *)inbuf);
 610                         op.inlen = hdr->sizes[i];
 611                 } else {
 612                         /* Create indirect DDE (scatterlist) */
 613                         nx842_build_scatterlist(inbuf, hdr->sizes[i] , &slin);
 614                         op.in = nx842_get_pa(slin.entries);
 615                         op.inlen = -nx842_get_scatterlist_size(&slin);
 616                 }
 617
 618                 /*
 619                  * NOTE: If the default max_sync_size is changed from 4k
 620                  * to 64k, remove the "likely" case below, since a
 621                  * scatterlist will always be needed.
 622                  */
 623                 if (likely(max_sync_size == NX842_HW_PAGE_SIZE)) {
 624                         /* Create direct DDE */
 625                         op.out = nx842_get_pa((void *)outbuf);
 626                         op.outlen = max_sync_size;
 627                 } else {
 628                         /* Create indirect DDE (scatterlist) */
 629                         nx842_build_scatterlist(outbuf, max_sync_size, &slout);
 630                         op.out = nx842_get_pa(slout.entries);
 631                         op.outlen = -nx842_get_scatterlist_size(&slout);
 632                 }
 633
 634                 /* Send request to pHyp */
 635                 ret = vio_h_cop_sync(local_devdata->vdev, &op);
 636
 637                 /* Check for pHyp error */
 638                 if (ret) {
 639                         dev_dbg(dev, "%s: vio_h_cop_sync error (ret=%d, hret=%ld)\n",
 640                                 __func__, ret, op.hcall_err);
 641                         dev = NULL;
 642                         goto sw;
 643                 }
 644
 645                 /* Check for hardware error */
 646                 ret = nx842_validate_result(dev, &csbcpb->csb);
 647                 if (ret) {
 648                         dev = NULL;
 649                         goto sw;
 650                 }
 651
 652                 /* HW decompression success */
 653                 inbuf += hdr->sizes[i];
 654                 outbuf += csbcpb->csb.processed_byte_count;
 655                 continue;
 656
 657 sw:
 658                 /* software decompression */
 659                 size = max_sync_size;
 660                 ret = sw842_decompress(
 661                         (unsigned char *)inbuf, hdr->sizes[i],
 662                         (unsigned char *)outbuf, &size, wmem);
 663                 if (ret)
 664                         pr_debug("%s: sw842_decompress failed with %d\n",
 665                                 __func__, ret);
 666
 667                 if (ret) {
 668                         if (ret != -ENOSPC && ret != -EINVAL &&
 669                                         ret != -EMSGSIZE)
 670                                 ret = -EIO;
 671                         goto unlock;
 672                 }
 673
 674                 /* SW decompression success */
 675                 inbuf += hdr->sizes[i];
 676                 outbuf += size;
 677         }
 678
 679         *outlen = (unsigned int)(outbuf - (unsigned long)out);
 680
 681 unlock:
 682         if (ret)
 683                 /* decompress fail */
 684                 nx842_inc_decomp_failed(local_devdata);
 685         else {
 686                 if (!dev)
 687                         /* software decompress */
 688                         nx842_inc_swdecomp(local_devdata);
 689                 nx842_inc_decomp_complete(local_devdata);
 690                 ibm_nx842_incr_hist(local_devdata->counters->decomp_times,
 691                         (get_tb() - start_time) / tb_ticks_per_usec);
 692         }
 693
 694         rcu_read_unlock();
 695         return ret;
 696 }
 697 EXPORT_SYMBOL_GPL(nx842_decompress);
 698
 699 /**
 700  * nx842_OF_set_defaults -- Set default (disabled) values for devdata
 701  *
 702  * @devdata - struct nx842_devdata to update
 703  *
 704  * Returns:
 705  *  0 on success
 706  *  -ENOENT if @devdata ptr is NULL
 707  */
 708 static int nx842_OF_set_defaults(struct nx842_devdata *devdata)
 709 {
 710         if (devdata) {
 711                 devdata->max_sync_size = 0;
 712                 devdata->max_sync_sg = 0;
 713                 devdata->max_sg_len = 0;
 714                 devdata->status = UNAVAILABLE;
 715                 return 0;
 716         } else
 717                 return -ENOENT;
 718 }
 719
 720 /**
 721  * nx842_OF_upd_status -- Update the device info from OF status prop
 722  *
 723  * The status property indicates if the accelerator is enabled.  If the
 724  * device is in the OF tree it indicates that the hardware is present.
 725  * The status field indicates if the device is enabled when the status
 726  * is 'okay'.  Otherwise the device driver will be disabled.
 727  *
 728  * @devdata - struct nx842_devdata to update
 729  * @prop - struct property point containing the maxsyncop for the update
 730  *
 731  * Returns:
 732  *  0 - Device is available
 733  *  -EINVAL - Device is not available
 734  */
 735 static int nx842_OF_upd_status(struct nx842_devdata *devdata,
 736                                         struct property *prop) {
 737         int ret = 0;
 738         const char *status = (const char *)prop->value;
 739
 740         if (!strncmp(status, "okay", (size_t)prop->length)) {
 741                 devdata->status = AVAILABLE;
 742         } else {
 743                 dev_info(devdata->dev, "%s: status '%s' is not 'okay'\n",
 744                                 __func__, status);
 745                 devdata->status = UNAVAILABLE;
 746         }
 747
 748         return ret;
 749 }
 750
 751 /**
 752  * nx842_OF_upd_maxsglen -- Update the device info from OF maxsglen prop
 753  *
 754  * Definition of the 'ibm,max-sg-len' OF property:
 755  *  This field indicates the maximum byte length of a scatter list
 756  *  for the platform facility. It is a single cell encoded as with encode-int.
 757  *
 758  * Example:
 759  *  # od -x ibm,max-sg-len
 760  *  0000000 0000 0ff0
 761  *
 762  *  In this example, the maximum byte length of a scatter list is
 763  *  0x0ff0 (4,080).
 764  *
 765  * @devdata - struct nx842_devdata to update
 766  * @prop - struct property point containing the maxsyncop for the update
 767  *
 768  * Returns:
 769  *  0 on success
 770  *  -EINVAL on failure
 771  */
 772 static int nx842_OF_upd_maxsglen(struct nx842_devdata *devdata,
 773                                         struct property *prop) {
 774         int ret = 0;
 775         const int *maxsglen = prop->value;
 776
 777         if (prop->length != sizeof(*maxsglen)) {
 778                 dev_err(devdata->dev, "%s: unexpected format for ibm,max-sg-len property\n", __func__);
 779                 dev_dbg(devdata->dev, "%s: ibm,max-sg-len is %d bytes long, expected %lu bytes\n", __func__,
 780                                 prop->length, sizeof(*maxsglen));
 781                 ret = -EINVAL;
 782         } else {
 783                 devdata->max_sg_len = (unsigned int)min(*maxsglen,
 784                                 (int)NX842_HW_PAGE_SIZE);
 785         }
 786
 787         return ret;
 788 }
 789
 790 /**
 791  * nx842_OF_upd_maxsyncop -- Update the device info from OF maxsyncop prop
 792  *
 793  * Definition of the 'ibm,max-sync-cop' OF property:
 794  *  Two series of cells.  The first series of cells represents the maximums
 795  *  that can be synchronously compressed. The second series of cells
 796  *  represents the maximums that can be synchronously decompressed.
 797  *  1. The first cell in each series contains the count of the number of
 798  *     data length, scatter list elements pairs that follow – each being
 799  *     of the form
 800  *    a. One cell data byte length
 801  *    b. One cell total number of scatter list elements
 802  *
 803  * Example:
 804  *  # od -x ibm,max-sync-cop
 805  *  0000000 0000 0001 0000 1000 0000 01fe 0000 0001
 806  *  0000020 0000 1000 0000 01fe
 807  *
 808  *  In this example, compression supports 0x1000 (4,096) data byte length
 809  *  and 0x1fe (510) total scatter list elements.  Decompression supports
 810  *  0x1000 (4,096) data byte length and 0x1f3 (510) total scatter list
 811  *  elements.
 812  *
 813  * @devdata - struct nx842_devdata to update
 814  * @prop - struct property point containing the maxsyncop for the update
 815  *
 816  * Returns:
 817  *  0 on success
 818  *  -EINVAL on failure
 819  */
 820 static int nx842_OF_upd_maxsyncop(struct nx842_devdata *devdata,
 821                                         struct property *prop) {
 822         int ret = 0;
 823         const struct maxsynccop_t {
 824                 int comp_elements;
 825                 int comp_data_limit;
 826                 int comp_sg_limit;
 827                 int decomp_elements;
 828                 int decomp_data_limit;
 829                 int decomp_sg_limit;
 830         } *maxsynccop;
 831
 832         if (prop->length != sizeof(*maxsynccop)) {
 833                 dev_err(devdata->dev, "%s: unexpected format for ibm,max-sync-cop property\n", __func__);
 834                 dev_dbg(devdata->dev, "%s: ibm,max-sync-cop is %d bytes long, expected %lu bytes\n", __func__, prop->length,
 835                                 sizeof(*maxsynccop));
 836                 ret = -EINVAL;
 837                 goto out;
 838         }
 839
 840         maxsynccop = (const struct maxsynccop_t *)prop->value;
 841
 842         /* Use one limit rather than separate limits for compression and
 843          * decompression. Set a maximum for this so as not to exceed the
 844          * size that the header can support and round the value down to
 845          * the hardware page size (4K) */
 846         devdata->max_sync_size =
 847                         (unsigned int)min(maxsynccop->comp_data_limit,
 848                                         maxsynccop->decomp_data_limit);
 849
 850         devdata->max_sync_size = min_t(unsigned int, devdata->max_sync_size,
 851                                         SIZE_64K);
 852
 853         if (devdata->max_sync_size < SIZE_4K) {
 854                 dev_err(devdata->dev, "%s: hardware max data size (%u) is "
 855                                 "less than the driver minimum, unable to use "
 856                                 "the hardware device\n",
 857                                 __func__, devdata->max_sync_size);
 858                 ret = -EINVAL;
 859                 goto out;
 860         }
 861
 862         devdata->max_sync_sg = (unsigned int)min(maxsynccop->comp_sg_limit,
 863                                                 maxsynccop->decomp_sg_limit);
 864         if (devdata->max_sync_sg < 1) {
 865                 dev_err(devdata->dev, "%s: hardware max sg size (%u) is "
 866                                 "less than the driver minimum, unable to use "
 867                                 "the hardware device\n",
 868                                 __func__, devdata->max_sync_sg);
 869                 ret = -EINVAL;
 870                 goto out;
 871         }
 872
 873 out:
 874         return ret;
 875 }
 876
 877 /**
 878  *
 879  * nx842_OF_upd -- Handle OF properties updates for the device.
 880  *
 881  * Set all properties from the OF tree.  Optionally, a new property
 882  * can be provided by the @new_prop pointer to overwrite an existing value.
 883  * The device will remain disabled until all values are valid, this function
 884  * will return an error for updates unless all values are valid.
 885  *
 886  * @new_prop: If not NULL, this property is being updated.  If NULL, update
 887  *  all properties from the current values in the OF tree.
 888  *
 889  * Returns:
 890  *  0 - Success
 891  *  -ENOMEM - Could not allocate memory for new devdata structure
 892  *  -EINVAL - property value not found, new_prop is not a recognized
 893  *      property for the device or property value is not valid.
 894  *  -ENODEV - Device is not available
 895  */
 896 static int nx842_OF_upd(struct property *new_prop)
 897 {
 898         struct nx842_devdata *old_devdata = NULL;
 899         struct nx842_devdata *new_devdata = NULL;
 900         struct device_node *of_node = NULL;
 901         struct property *status = NULL;
 902         struct property *maxsglen = NULL;
 903         struct property *maxsyncop = NULL;
 904         int ret = 0;
 905         unsigned long flags;
 906
 907         spin_lock_irqsave(&devdata_mutex, flags);
 908         old_devdata = rcu_dereference_check(devdata,
 909                         lockdep_is_held(&devdata_mutex));
 910         if (old_devdata)
 911                 of_node = old_devdata->dev->of_node;
 912
 913         if (!old_devdata || !of_node) {
 914                 pr_err("%s: device is not available\n", __func__);
 915                 spin_unlock_irqrestore(&devdata_mutex, flags);
 916                 return -ENODEV;
 917         }
 918
 919         new_devdata = kzalloc(sizeof(*new_devdata), GFP_NOFS);
 920         if (!new_devdata) {
 921                 dev_err(old_devdata->dev, "%s: Could not allocate memory for device data\n", __func__);
 922                 ret = -ENOMEM;
 923                 goto error_out;
 924         }
 925
 926         memcpy(new_devdata, old_devdata, sizeof(*old_devdata));
 927         new_devdata->counters = old_devdata->counters;
 928
 929         /* Set ptrs for existing properties */
 930         status = of_find_property(of_node, "status", NULL);
 931         maxsglen = of_find_property(of_node, "ibm,max-sg-len", NULL);
 932         maxsyncop = of_find_property(of_node, "ibm,max-sync-cop", NULL);
 933         if (!status || !maxsglen || !maxsyncop) {
 934                 dev_err(old_devdata->dev, "%s: Could not locate device properties\n", __func__);
 935                 ret = -EINVAL;
 936                 goto error_out;
 937         }
 938
 939         /*
 940          * If this is a property update, there are only certain properties that
 941          * we care about. Bail if it isn't in the below list
 942          */
 943         if (new_prop && (strncmp(new_prop->name, "status", new_prop->length) ||
 944                          strncmp(new_prop->name, "ibm,max-sg-len", new_prop->length) ||
 945                          strncmp(new_prop->name, "ibm,max-sync-cop", new_prop->length)))
 946                 goto out;
 947
 948         /* Perform property updates */
 949         ret = nx842_OF_upd_status(new_devdata, status);
 950         if (ret)
 951                 goto error_out;
 952
 953         ret = nx842_OF_upd_maxsglen(new_devdata, maxsglen);
 954         if (ret)
 955                 goto error_out;
 956
 957         ret = nx842_OF_upd_maxsyncop(new_devdata, maxsyncop);
 958         if (ret)
 959                 goto error_out;
 960
 961 out:
 962         dev_info(old_devdata->dev, "%s: max_sync_size new:%u old:%u\n",
 963                         __func__, new_devdata->max_sync_size,
 964                         old_devdata->max_sync_size);
 965         dev_info(old_devdata->dev, "%s: max_sync_sg new:%u old:%u\n",
 966                         __func__, new_devdata->max_sync_sg,
 967                         old_devdata->max_sync_sg);
 968         dev_info(old_devdata->dev, "%s: max_sg_len new:%u old:%u\n",
 969                         __func__, new_devdata->max_sg_len,
 970                         old_devdata->max_sg_len);
 971
 972         rcu_assign_pointer(devdata, new_devdata);
 973         spin_unlock_irqrestore(&devdata_mutex, flags);
 974         synchronize_rcu();
 975         dev_set_drvdata(new_devdata->dev, new_devdata);
 976         kfree(old_devdata);
 977         return 0;
 978
 979 error_out:
 980         if (new_devdata) {
 981                 dev_info(old_devdata->dev, "%s: device disabled\n", __func__);
 982                 nx842_OF_set_defaults(new_devdata);
 983                 rcu_assign_pointer(devdata, new_devdata);
 984                 spin_unlock_irqrestore(&devdata_mutex, flags);
 985                 synchronize_rcu();
 986                 dev_set_drvdata(new_devdata->dev, new_devdata);
 987                 kfree(old_devdata);
 988         } else {
 989                 dev_err(old_devdata->dev, "%s: could not update driver from hardware\n", __func__);
 990                 spin_unlock_irqrestore(&devdata_mutex, flags);
 991         }
 992
 993         if (!ret)
 994                 ret = -EINVAL;
 995         return ret;
 996 }
 997
 998 /**
 999  * nx842_OF_notifier - Process updates to OF properties for the device
1000  *
1001  * @np: notifier block
1002  * @action: notifier action
1003  * @update: struct pSeries_reconfig_prop_update pointer if action is
1004  *      PSERIES_UPDATE_PROPERTY
1005  *
1006  * Returns:
1007  *      NOTIFY_OK on success
1008  *      NOTIFY_BAD encoded with error number on failure, use
1009  *              notifier_to_errno() to decode this value
1010  */
1011 static int nx842_OF_notifier(struct notifier_block *np, unsigned long action,
1012                              void *update)
1013 {
1014         struct of_prop_reconfig *upd = update;
1015         struct nx842_devdata *local_devdata;
1016         struct device_node *node = NULL;
1017
1018         rcu_read_lock();
1019         local_devdata = rcu_dereference(devdata);
1020         if (local_devdata)
1021                 node = local_devdata->dev->of_node;
1022
1023         if (local_devdata &&
1024                         action == OF_RECONFIG_UPDATE_PROPERTY &&
1025                         !strcmp(upd->dn->name, node->name)) {
1026                 rcu_read_unlock();
1027                 nx842_OF_upd(upd->prop);
1028         } else
1029                 rcu_read_unlock();
1030
1031         return NOTIFY_OK;
1032 }
1033
1034 static struct notifier_block nx842_of_nb = {
1035         .notifier_call = nx842_OF_notifier,
1036 };
1037
1038 #define nx842_counter_read(_name)                                       \
1039 static ssize_t nx842_##_name##_show(struct device *dev,         \
1040                 struct device_attribute *attr,                          \
1041                 char *buf) {                                            \
1042         struct nx842_devdata *local_devdata;                    \
1043         int p = 0;                                                      \
1044         rcu_read_lock();                                                \
1045         local_devdata = rcu_dereference(devdata);                       \
1046         if (local_devdata)                                              \
1047                 p = snprintf(buf, PAGE_SIZE, "%ld\n",                   \
1048                        atomic64_read(&local_devdata->counters->_name)); \
1049         rcu_read_unlock();                                              \
1050         return p;                                                       \
1051 }
1052
1053 #define NX842DEV_COUNTER_ATTR_RO(_name)                                 \
1054         nx842_counter_read(_name);                                      \
1055         static struct device_attribute dev_attr_##_name = __ATTR(_name, \
1056                                                 0444,                   \
1057                                                 nx842_##_name##_show,\
1058                                                 NULL);
1059
1060 NX842DEV_COUNTER_ATTR_RO(comp_complete);
1061 NX842DEV_COUNTER_ATTR_RO(comp_failed);
1062 NX842DEV_COUNTER_ATTR_RO(decomp_complete);
1063 NX842DEV_COUNTER_ATTR_RO(decomp_failed);
1064 NX842DEV_COUNTER_ATTR_RO(swdecomp);
1065
1066 static ssize_t nx842_timehist_show(struct device *,
1067                 struct device_attribute *, char *);
1068
1069 static struct device_attribute dev_attr_comp_times = __ATTR(comp_times, 0444,
1070                 nx842_timehist_show, NULL);
1071 static struct device_attribute dev_attr_decomp_times = __ATTR(decomp_times,
1072                 0444, nx842_timehist_show, NULL);
1073
1074 static ssize_t nx842_timehist_show(struct device *dev,
1075                 struct device_attribute *attr, char *buf) {
1076         char *p = buf;
1077         struct nx842_devdata *local_devdata;
1078         atomic64_t *times;
1079         int bytes_remain = PAGE_SIZE;
1080         int bytes;
1081         int i;
1082
1083         rcu_read_lock();
1084         local_devdata = rcu_dereference(devdata);
1085         if (!local_devdata) {
1086                 rcu_read_unlock();
1087                 return 0;
1088         }
1089
1090         if (attr == &dev_attr_comp_times)
1091                 times = local_devdata->counters->comp_times;
1092         else if (attr == &dev_attr_decomp_times)
1093                 times = local_devdata->counters->decomp_times;
1094         else {
1095                 rcu_read_unlock();
1096                 return 0;
1097         }
1098
1099         for (i = 0; i < (NX842_HIST_SLOTS - 2); i++) {
1100                 bytes = snprintf(p, bytes_remain, "%u-%uus:\t%ld\n",
1101                                i ? (2<<(i-1)) : 0, (2<<i)-1,
1102                                atomic64_read(&times[i]));
1103                 bytes_remain -= bytes;
1104                 p += bytes;
1105         }
1106         /* The last bucket holds everything over
1107          * 2<<(NX842_HIST_SLOTS - 2) us */
1108         bytes = snprintf(p, bytes_remain, "%uus - :\t%ld\n",
1109                         2<<(NX842_HIST_SLOTS - 2),
1110                         atomic64_read(&times[(NX842_HIST_SLOTS - 1)]));
1111         p += bytes;
1112
1113         rcu_read_unlock();
1114         return p - buf;
1115 }
1116
1117 static struct attribute *nx842_sysfs_entries[] = {
1118         &dev_attr_comp_complete.attr,
1119         &dev_attr_comp_failed.attr,
1120         &dev_attr_decomp_complete.attr,
1121         &dev_attr_decomp_failed.attr,
1122         &dev_attr_swdecomp.attr,
1123         &dev_attr_comp_times.attr,
1124         &dev_attr_decomp_times.attr,
1125         NULL,
1126 };
1127
1128 static struct attribute_group nx842_attribute_group = {
1129         .name = NULL,           /* put in device directory */
1130         .attrs = nx842_sysfs_entries,
1131 };
1132
1133 static int __init nx842_probe(struct vio_dev *viodev,
1134                                   const struct vio_device_id *id)
1135 {
1136         struct nx842_devdata *old_devdata, *new_devdata = NULL;
1137         unsigned long flags;
1138         int ret = 0;
1139
1140         spin_lock_irqsave(&devdata_mutex, flags);
1141         old_devdata = rcu_dereference_check(devdata,
1142                         lockdep_is_held(&devdata_mutex));
1143
1144         if (old_devdata && old_devdata->vdev != NULL) {
1145                 dev_err(&viodev->dev, "%s: Attempt to register more than one instance of the hardware\n", __func__);
1146                 ret = -1;
1147                 goto error_unlock;
1148         }
1149
1150         dev_set_drvdata(&viodev->dev, NULL);
1151
1152         new_devdata = kzalloc(sizeof(*new_devdata), GFP_NOFS);
1153         if (!new_devdata) {
1154                 dev_err(&viodev->dev, "%s: Could not allocate memory for device data\n", __func__);
1155                 ret = -ENOMEM;
1156                 goto error_unlock;
1157         }
1158
1159         new_devdata->counters = kzalloc(sizeof(*new_devdata->counters),
1160                         GFP_NOFS);
1161         if (!new_devdata->counters) {
1162                 dev_err(&viodev->dev, "%s: Could not allocate memory for performance counters\n", __func__);
1163                 ret = -ENOMEM;
1164                 goto error_unlock;
1165         }
1166
1167         new_devdata->vdev = viodev;
1168         new_devdata->dev = &viodev->dev;
1169         nx842_OF_set_defaults(new_devdata);
1170
1171         rcu_assign_pointer(devdata, new_devdata);
1172         spin_unlock_irqrestore(&devdata_mutex, flags);
1173         synchronize_rcu();
1174         kfree(old_devdata);
1175
1176         of_reconfig_notifier_register(&nx842_of_nb);
1177
1178         ret = nx842_OF_upd(NULL);
1179         if (ret && ret != -ENODEV) {
1180                 dev_err(&viodev->dev, "could not parse device tree. %d\n", ret);
1181                 ret = -1;
1182                 goto error;
1183         }
1184
1185         rcu_read_lock();
1186         dev_set_drvdata(&viodev->dev, rcu_dereference(devdata));
1187         rcu_read_unlock();
1188
1189         if (sysfs_create_group(&viodev->dev.kobj, &nx842_attribute_group)) {
1190                 dev_err(&viodev->dev, "could not create sysfs device attributes\n");
1191                 ret = -1;
1192                 goto error;
1193         }
1194
1195         return 0;
1196
1197 error_unlock:
1198         spin_unlock_irqrestore(&devdata_mutex, flags);
1199         if (new_devdata)
1200                 kfree(new_devdata->counters);
1201         kfree(new_devdata);
1202 error:
1203         return ret;
1204 }
1205
1206 static int __exit nx842_remove(struct vio_dev *viodev)
1207 {
1208         struct nx842_devdata *old_devdata;
1209         unsigned long flags;
1210
1211         pr_info("Removing IBM Power 842 compression device\n");
1212         sysfs_remove_group(&viodev->dev.kobj, &nx842_attribute_group);
1213
1214         spin_lock_irqsave(&devdata_mutex, flags);
1215         old_devdata = rcu_dereference_check(devdata,
1216                         lockdep_is_held(&devdata_mutex));
1217         of_reconfig_notifier_unregister(&nx842_of_nb);
1218         RCU_INIT_POINTER(devdata, NULL);
1219         spin_unlock_irqrestore(&devdata_mutex, flags);
1220         synchronize_rcu();
1221         dev_set_drvdata(&viodev->dev, NULL);
1222         if (old_devdata)
1223                 kfree(old_devdata->counters);
1224         kfree(old_devdata);
1225         return 0;
1226 }
1227
1228 static struct vio_device_id nx842_driver_ids[] = {
1229         {"ibm,compression-v1", "ibm,compression"},
1230         {"", ""},
1231 };
1232
1233 static struct vio_driver nx842_driver = {
1234         .name = MODULE_NAME,
1235         .probe = nx842_probe,
1236         .remove = __exit_p(nx842_remove),
1237         .get_desired_dma = nx842_get_desired_dma,
1238         .id_table = nx842_driver_ids,
1239 };
1240
1241 static int __init nx842_init(void)
1242 {
1243         struct nx842_devdata *new_devdata;
1244         pr_info("Registering IBM Power 842 compression driver\n");
1245
1246         RCU_INIT_POINTER(devdata, NULL);
1247         new_devdata = kzalloc(sizeof(*new_devdata), GFP_KERNEL);
1248         if (!new_devdata) {
1249                 pr_err("Could not allocate memory for device data\n");
1250                 return -ENOMEM;
1251         }
1252         new_devdata->status = UNAVAILABLE;
1253         RCU_INIT_POINTER(devdata, new_devdata);
1254
1255         return vio_register_driver(&nx842_driver);
1256 }
1257
1258 module_init(nx842_init);
1259
1260 static void __exit nx842_exit(void)
1261 {
1262         struct nx842_devdata *old_devdata;
1263         unsigned long flags;
1264
1265         pr_info("Exiting IBM Power 842 compression driver\n");
1266         spin_lock_irqsave(&devdata_mutex, flags);
1267         old_devdata = rcu_dereference_check(devdata,
1268                         lockdep_is_held(&devdata_mutex));
1269         RCU_INIT_POINTER(devdata, NULL);
1270         spin_unlock_irqrestore(&devdata_mutex, flags);
1271         synchronize_rcu();
1272         if (old_devdata)
1273                 dev_set_drvdata(old_devdata->dev, NULL);
1274         kfree(old_devdata);
1275         vio_unregister_driver(&nx842_driver);
1276 }
1277
1278 module_exit(nx842_exit);
1279
1280 /*********************************
1281  * 842 software decompressor
1282 *********************************/
1283 typedef int (*sw842_template_op)(const char **, int *, unsigned char **,
1284                                                 struct sw842_fifo *);
1285
1286 static int sw842_data8(const char **, int *, unsigned char **,
1287                                                 struct sw842_fifo *);
1288 static int sw842_data4(const char **, int *, unsigned char **,
1289                                                 struct sw842_fifo *);
1290 static int sw842_data2(const char **, int *, unsigned char **,
1291                                                 struct sw842_fifo *);
1292 static int sw842_ptr8(const char **, int *, unsigned char **,
1293                                                 struct sw842_fifo *);
1294 static int sw842_ptr4(const char **, int *, unsigned char **,
1295                                                 struct sw842_fifo *);
1296 static int sw842_ptr2(const char **, int *, unsigned char **,
1297                                                 struct sw842_fifo *);
1298
1299 /* special templates */
1300 #define SW842_TMPL_REPEAT 0x1B
1301 #define SW842_TMPL_ZEROS 0x1C
1302 #define SW842_TMPL_EOF 0x1E
1303
1304 static sw842_template_op sw842_tmpl_ops[26][4] = {
1305         { sw842_data8, NULL}, /* 0 (00000) */
1306         { sw842_data4, sw842_data2, sw842_ptr2,  NULL},
1307         { sw842_data4, sw842_ptr2,  sw842_data2, NULL},
1308         { sw842_data4, sw842_ptr2,  sw842_ptr2,  NULL},
1309         { sw842_data4, sw842_ptr4,  NULL},
1310         { sw842_data2, sw842_ptr2,  sw842_data4, NULL},
1311         { sw842_data2, sw842_ptr2,  sw842_data2, sw842_ptr2},
1312         { sw842_data2, sw842_ptr2,  sw842_ptr2,  sw842_data2},
1313         { sw842_data2, sw842_ptr2,  sw842_ptr2,  sw842_ptr2,},
1314         { sw842_data2, sw842_ptr2,  sw842_ptr4,  NULL},
1315         { sw842_ptr2,  sw842_data2, sw842_data4, NULL}, /* 10 (01010) */
1316         { sw842_ptr2,  sw842_data4, sw842_ptr2,  NULL},
1317         { sw842_ptr2,  sw842_data2, sw842_ptr2,  sw842_data2},
1318         { sw842_ptr2,  sw842_data2, sw842_ptr2,  sw842_ptr2},
1319         { sw842_ptr2,  sw842_data2, sw842_ptr4,  NULL},
1320         { sw842_ptr2,  sw842_ptr2,  sw842_data4, NULL},
1321         { sw842_ptr2,  sw842_ptr2,  sw842_data2, sw842_ptr2},
1322         { sw842_ptr2,  sw842_ptr2,  sw842_ptr2,  sw842_data2},
1323         { sw842_ptr2,  sw842_ptr2,  sw842_ptr2,  sw842_ptr2},
1324         { sw842_ptr2,  sw842_ptr2,  sw842_ptr4,  NULL},
1325         { sw842_ptr4,  sw842_data4, NULL}, /* 20 (10100) */
1326         { sw842_ptr4,  sw842_data2, sw842_ptr2,  NULL},
1327         { sw842_ptr4,  sw842_ptr2,  sw842_data2, NULL},
1328         { sw842_ptr4,  sw842_ptr2,  sw842_ptr2,  NULL},
1329         { sw842_ptr4,  sw842_ptr4,  NULL},
1330         { sw842_ptr8,  NULL}
1331 };
1332
1333 /* Software decompress helpers */
1334
1335 static uint8_t sw842_get_byte(const char *buf, int bit)
1336 {
1337         uint8_t tmpl;
1338         uint16_t tmp;
1339         tmp = htons(*(uint16_t *)(buf));
1340         tmp = (uint16_t)(tmp << bit);
1341         tmp = ntohs(tmp);
1342         memcpy(&tmpl, &tmp, 1);
1343         return tmpl;
1344 }
1345
1346 static uint8_t sw842_get_template(const char **buf, int *bit)
1347 {
1348         uint8_t byte;
1349         byte = sw842_get_byte(*buf, *bit);
1350         byte = byte >> 3;
1351         byte &= 0x1F;
1352         *buf += (*bit + 5) / 8;
1353         *bit = (*bit + 5) % 8;
1354         return byte;
1355 }
1356
1357 /* repeat_count happens to be 5-bit too (like the template) */
1358 static uint8_t sw842_get_repeat_count(const char **buf, int *bit)
1359 {
1360         uint8_t byte;
1361         byte = sw842_get_byte(*buf, *bit);
1362         byte = byte >> 2;
1363         byte &= 0x3F;
1364         *buf += (*bit + 6) / 8;
1365         *bit = (*bit + 6) % 8;
1366         return byte;
1367 }
1368
1369 static uint8_t sw842_get_ptr2(const char **buf, int *bit)
1370 {
1371         uint8_t ptr;
1372         ptr = sw842_get_byte(*buf, *bit);
1373         (*buf)++;
1374         return ptr;
1375 }
1376
1377 static uint16_t sw842_get_ptr4(const char **buf, int *bit,
1378                 struct sw842_fifo *fifo)
1379 {
1380         uint16_t ptr;
1381         ptr = htons(*(uint16_t *)(*buf));
1382         ptr = (uint16_t)(ptr << *bit);
1383         ptr = ptr >> 7;
1384         ptr &= 0x01FF;
1385         *buf += (*bit + 9) / 8;
1386         *bit = (*bit + 9) % 8;
1387         return ptr;
1388 }
1389
1390 static uint8_t sw842_get_ptr8(const char **buf, int *bit,
1391                 struct sw842_fifo *fifo)
1392 {
1393         return sw842_get_ptr2(buf, bit);
1394 }
1395
1396 /* Software decompress template ops */
1397
1398 static int sw842_data8(const char **inbuf, int *inbit,
1399                 unsigned char **outbuf, struct sw842_fifo *fifo)
1400 {
1401         int ret;
1402
1403         ret = sw842_data4(inbuf, inbit, outbuf, fifo);
1404         if (ret)
1405                 return ret;
1406         ret = sw842_data4(inbuf, inbit, outbuf, fifo);
1407         return ret;
1408 }
1409
1410 static int sw842_data4(const char **inbuf, int *inbit,
1411                 unsigned char **outbuf, struct sw842_fifo *fifo)
1412 {
1413         int ret;
1414
1415         ret = sw842_data2(inbuf, inbit, outbuf, fifo);
1416         if (ret)
1417                 return ret;
1418         ret = sw842_data2(inbuf, inbit, outbuf, fifo);
1419         return ret;
1420 }
1421
1422 static int sw842_data2(const char **inbuf, int *inbit,
1423                 unsigned char **outbuf, struct sw842_fifo *fifo)
1424 {
1425         **outbuf = sw842_get_byte(*inbuf, *inbit);
1426         (*inbuf)++;
1427         (*outbuf)++;
1428         **outbuf = sw842_get_byte(*inbuf, *inbit);
1429         (*inbuf)++;
1430         (*outbuf)++;
1431         return 0;
1432 }
1433
1434 static int sw842_ptr8(const char **inbuf, int *inbit,
1435                 unsigned char **outbuf, struct sw842_fifo *fifo)
1436 {
1437         uint8_t ptr;
1438         ptr = sw842_get_ptr8(inbuf, inbit, fifo);
1439         if (!fifo->f84_full && (ptr >= fifo->f8_count))
1440                 return 1;
1441         memcpy(*outbuf, fifo->f8[ptr], 8);
1442         *outbuf += 8;
1443         return 0;
1444 }
1445
1446 static int sw842_ptr4(const char **inbuf, int *inbit,
1447                 unsigned char **outbuf, struct sw842_fifo *fifo)
1448 {
1449         uint16_t ptr;
1450         ptr = sw842_get_ptr4(inbuf, inbit, fifo);
1451         if (!fifo->f84_full && (ptr >= fifo->f4_count))
1452                 return 1;
1453         memcpy(*outbuf, fifo->f4[ptr], 4);
1454         *outbuf += 4;
1455         return 0;
1456 }
1457
1458 static int sw842_ptr2(const char **inbuf, int *inbit,
1459                 unsigned char **outbuf, struct sw842_fifo *fifo)
1460 {
1461         uint8_t ptr;
1462         ptr = sw842_get_ptr2(inbuf, inbit);
1463         if (!fifo->f2_full && (ptr >= fifo->f2_count))
1464                 return 1;
1465         memcpy(*outbuf, fifo->f2[ptr], 2);
1466         *outbuf += 2;
1467         return 0;
1468 }
1469
1470 static void sw842_copy_to_fifo(const char *buf, struct sw842_fifo *fifo)
1471 {
1472         unsigned char initial_f2count = fifo->f2_count;
1473
1474         memcpy(fifo->f8[fifo->f8_count], buf, 8);
1475         fifo->f4_count += 2;
1476         fifo->f8_count += 1;
1477
1478         if (!fifo->f84_full && fifo->f4_count >= 512) {
1479                 fifo->f84_full = 1;
1480                 fifo->f4_count /= 512;
1481         }
1482
1483         memcpy(fifo->f2[fifo->f2_count++], buf, 2);
1484         memcpy(fifo->f2[fifo->f2_count++], buf + 2, 2);
1485         memcpy(fifo->f2[fifo->f2_count++], buf + 4, 2);
1486         memcpy(fifo->f2[fifo->f2_count++], buf + 6, 2);
1487         if (fifo->f2_count < initial_f2count)
1488                 fifo->f2_full = 1;
1489 }
1490
1491 static int sw842_decompress(const unsigned char *src, int srclen,
1492                         unsigned char *dst, int *destlen,
1493                         const void *wrkmem)
1494 {
1495         uint8_t tmpl;
1496         const char *inbuf;
1497         int inbit = 0;
1498         unsigned char *outbuf, *outbuf_end, *origbuf, *prevbuf;
1499         const char *inbuf_end;
1500         sw842_template_op op;
1501         int opindex;
1502         int i, repeat_count;
1503         struct sw842_fifo *fifo;
1504         int ret = 0;
1505
1506         fifo = &((struct nx842_workmem *)(wrkmem))->swfifo;
1507         memset(fifo, 0, sizeof(*fifo));
1508
1509         origbuf = NULL;
1510         inbuf = src;
1511         inbuf_end = src + srclen;
1512         outbuf = dst;
1513         outbuf_end = dst + *destlen;
1514
1515         while ((tmpl = sw842_get_template(&inbuf, &inbit)) != SW842_TMPL_EOF) {
1516                 if (inbuf >= inbuf_end) {
1517                         ret = -EINVAL;
1518                         goto out;
1519                 }
1520
1521                 opindex = 0;
1522                 prevbuf = origbuf;
1523                 origbuf = outbuf;
1524                 switch (tmpl) {
1525                 case SW842_TMPL_REPEAT:
1526                         if (prevbuf == NULL) {
1527                                 ret = -EINVAL;
1528                                 goto out;
1529                         }
1530
1531                         repeat_count = sw842_get_repeat_count(&inbuf,
1532                                                                 &inbit) + 1;
1533
1534                         /* Did the repeat count advance past the end of input */
1535                         if (inbuf > inbuf_end) {
1536                                 ret = -EINVAL;
1537                                 goto out;
1538                         }
1539
1540                         for (i = 0; i < repeat_count; i++) {
1541                                 /* Would this overflow the output buffer */
1542                                 if ((outbuf + 8) > outbuf_end) {
1543                                         ret = -ENOSPC;
1544                                         goto out;
1545                                 }
1546
1547                                 memcpy(outbuf, prevbuf, 8);
1548                                 sw842_copy_to_fifo(outbuf, fifo);
1549                                 outbuf += 8;
1550                         }
1551                         break;
1552
1553                 case SW842_TMPL_ZEROS:
1554                         /* Would this overflow the output buffer */
1555                         if ((outbuf + 8) > outbuf_end) {
1556                                 ret = -ENOSPC;
1557                                 goto out;
1558                         }
1559
1560                         memset(outbuf, 0, 8);
1561                         sw842_copy_to_fifo(outbuf, fifo);
1562                         outbuf += 8;
1563                         break;
1564
1565                 default:
1566                         if (tmpl > 25) {
1567                                 ret = -EINVAL;
1568                                 goto out;
1569                         }
1570
1571                         /* Does this go past the end of the input buffer */
1572                         if ((inbuf + 2) > inbuf_end) {
1573                                 ret = -EINVAL;
1574                                 goto out;
1575                         }
1576
1577                         /* Would this overflow the output buffer */
1578                         if ((outbuf + 8) > outbuf_end) {
1579                                 ret = -ENOSPC;
1580                                 goto out;
1581                         }
1582
1583                         while (opindex < 4 &&
1584                                 (op = sw842_tmpl_ops[tmpl][opindex++])
1585                                         != NULL) {
1586                                 ret = (*op)(&inbuf, &inbit, &outbuf, fifo);
1587                                 if (ret) {
1588                                         ret = -EINVAL;
1589                                         goto out;
1590                                 }
1591                                 sw842_copy_to_fifo(origbuf, fifo);
1592                         }
1593                 }
1594         }
1595
1596 out:
1597         if (!ret)
1598                 *destlen = (unsigned int)(outbuf - dst);
1599         else
1600                 *destlen = 0;
1601
1602         return ret;
1603 }