linux/drivers/hwtracing/intel_th/msu.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Intel(R) Trace Hub Memory Storage Unit
   4 *
   5 * Copyright (C) 2014-2015 Intel Corporation.
   6 */
   7
   8#define pr_fmt(fmt)     KBUILD_MODNAME ": " fmt
   9
  10#include <linux/types.h>
  11#include <linux/module.h>
  12#include <linux/device.h>
  13#include <linux/uaccess.h>
  14#include <linux/sizes.h>
  15#include <linux/printk.h>
  16#include <linux/slab.h>
  17#include <linux/mm.h>
  18#include <linux/fs.h>
  19#include <linux/io.h>
  20#include <linux/workqueue.h>
  21#include <linux/dma-mapping.h>
  22
  23#ifdef CONFIG_X86
  24#include <asm/set_memory.h>
  25#endif
  26
  27#include <linux/intel_th.h>
  28#include "intel_th.h"
  29#include "msu.h"
  30
  31#define msc_dev(x) (&(x)->thdev->dev)
  32
  33/*
  34 * Lockout state transitions:
  35 *   READY -> INUSE -+-> LOCKED -+-> READY -> etc.
  36 *                   \-----------/
  37 * WIN_READY:   window can be used by HW
  38 * WIN_INUSE:   window is in use
  39 * WIN_LOCKED:  window is filled up and is being processed by the buffer
  40 * handling code
  41 *
  42 * All state transitions happen automatically, except for the LOCKED->READY,
  43 * which needs to be signalled by the buffer code by calling
  44 * intel_th_msc_window_unlock().
  45 *
  46 * When the interrupt handler has to switch to the next window, it checks
  47 * whether it's READY, and if it is, it performs the switch and tracing
  48 * continues. If it's LOCKED, it stops the trace.
  49 */
  50enum lockout_state {
  51        WIN_READY = 0,
  52        WIN_INUSE,
  53        WIN_LOCKED
  54};
  55
  56/**
  57 * struct msc_window - multiblock mode window descriptor
  58 * @entry:      window list linkage (msc::win_list)
  59 * @pgoff:      page offset into the buffer that this window starts at
  60 * @lockout:    lockout state, see comment below
  61 * @lo_lock:    lockout state serialization
  62 * @nr_blocks:  number of blocks (pages) in this window
  63 * @nr_segs:    number of segments in this window (<= @nr_blocks)
  64 * @_sgt:       array of block descriptors
  65 * @sgt:        array of block descriptors
  66 */
  67struct msc_window {
  68        struct list_head        entry;
  69        unsigned long           pgoff;
  70        enum lockout_state      lockout;
  71        spinlock_t              lo_lock;
  72        unsigned int            nr_blocks;
  73        unsigned int            nr_segs;
  74        struct msc              *msc;
  75        struct sg_table         _sgt;
  76        struct sg_table         *sgt;
  77};
  78
  79/**
  80 * struct msc_iter - iterator for msc buffer
  81 * @entry:              msc::iter_list linkage
  82 * @msc:                pointer to the MSC device
  83 * @start_win:          oldest window
  84 * @win:                current window
  85 * @offset:             current logical offset into the buffer
  86 * @start_block:        oldest block in the window
  87 * @block:              block number in the window
  88 * @block_off:          offset into current block
  89 * @wrap_count:         block wrapping handling
  90 * @eof:                end of buffer reached
  91 */
  92struct msc_iter {
  93        struct list_head        entry;
  94        struct msc              *msc;
  95        struct msc_window       *start_win;
  96        struct msc_window       *win;
  97        unsigned long           offset;
  98        struct scatterlist      *start_block;
  99        struct scatterlist      *block;
 100        unsigned int            block_off;
 101        unsigned int            wrap_count;
 102        unsigned int            eof;
 103};
 104
 105/**
 106 * struct msc - MSC device representation
 107 * @reg_base:           register window base address
 108 * @thdev:              intel_th_device pointer
 109 * @mbuf:               MSU buffer, if assigned
 110 * @mbuf_priv           MSU buffer's private data, if @mbuf
 111 * @win_list:           list of windows in multiblock mode
 112 * @single_sgt:         single mode buffer
 113 * @cur_win:            current window
 114 * @nr_pages:           total number of pages allocated for this buffer
 115 * @single_sz:          amount of data in single mode
 116 * @single_wrap:        single mode wrap occurred
 117 * @base:               buffer's base pointer
 118 * @base_addr:          buffer's base address
 119 * @user_count:         number of users of the buffer
 120 * @mmap_count:         number of mappings
 121 * @buf_mutex:          mutex to serialize access to buffer-related bits
 122
 123 * @enabled:            MSC is enabled
 124 * @wrap:               wrapping is enabled
 125 * @mode:               MSC operating mode
 126 * @burst_len:          write burst length
 127 * @index:              number of this MSC in the MSU
 128 */
 129struct msc {
 130        void __iomem            *reg_base;
 131        void __iomem            *msu_base;
 132        struct intel_th_device  *thdev;
 133
 134        const struct msu_buffer *mbuf;
 135        void                    *mbuf_priv;
 136
 137        struct work_struct      work;
 138        struct list_head        win_list;
 139        struct sg_table         single_sgt;
 140        struct msc_window       *cur_win;
 141        struct msc_window       *switch_on_unlock;
 142        unsigned long           nr_pages;
 143        unsigned long           single_sz;
 144        unsigned int            single_wrap : 1;
 145        void                    *base;
 146        dma_addr_t              base_addr;
 147        u32                     orig_addr;
 148        u32                     orig_sz;
 149
 150        /* <0: no buffer, 0: no users, >0: active users */
 151        atomic_t                user_count;
 152
 153        atomic_t                mmap_count;
 154        struct mutex            buf_mutex;
 155
 156        struct list_head        iter_list;
 157
 158        bool                    stop_on_full;
 159
 160        /* config */
 161        unsigned int            enabled : 1,
 162                                wrap    : 1,
 163                                do_irq  : 1,
 164                                multi_is_broken : 1;
 165        unsigned int            mode;
 166        unsigned int            burst_len;
 167        unsigned int            index;
 168};
 169
 170static LIST_HEAD(msu_buffer_list);
 171static DEFINE_MUTEX(msu_buffer_mutex);
 172
 173/**
 174 * struct msu_buffer_entry - internal MSU buffer bookkeeping
 175 * @entry:      link to msu_buffer_list
 176 * @mbuf:       MSU buffer object
 177 * @owner:      module that provides this MSU buffer
 178 */
 179struct msu_buffer_entry {
 180        struct list_head        entry;
 181        const struct msu_buffer *mbuf;
 182        struct module           *owner;
 183};
 184
 185static struct msu_buffer_entry *__msu_buffer_entry_find(const char *name)
 186{
 187        struct msu_buffer_entry *mbe;
 188
 189        lockdep_assert_held(&msu_buffer_mutex);
 190
 191        list_for_each_entry(mbe, &msu_buffer_list, entry) {
 192                if (!strcmp(mbe->mbuf->name, name))
 193                        return mbe;
 194        }
 195
 196        return NULL;
 197}
 198
 199static const struct msu_buffer *
 200msu_buffer_get(const char *name)
 201{
 202        struct msu_buffer_entry *mbe;
 203
 204        mutex_lock(&msu_buffer_mutex);
 205        mbe = __msu_buffer_entry_find(name);
 206        if (mbe && !try_module_get(mbe->owner))
 207                mbe = NULL;
 208        mutex_unlock(&msu_buffer_mutex);
 209
 210        return mbe ? mbe->mbuf : NULL;
 211}
 212
 213static void msu_buffer_put(const struct msu_buffer *mbuf)
 214{
 215        struct msu_buffer_entry *mbe;
 216
 217        mutex_lock(&msu_buffer_mutex);
 218        mbe = __msu_buffer_entry_find(mbuf->name);
 219        if (mbe)
 220                module_put(mbe->owner);
 221        mutex_unlock(&msu_buffer_mutex);
 222}
 223
 224int intel_th_msu_buffer_register(const struct msu_buffer *mbuf,
 225                                 struct module *owner)
 226{
 227        struct msu_buffer_entry *mbe;
 228        int ret = 0;
 229
 230        mbe = kzalloc(sizeof(*mbe), GFP_KERNEL);
 231        if (!mbe)
 232                return -ENOMEM;
 233
 234        mutex_lock(&msu_buffer_mutex);
 235        if (__msu_buffer_entry_find(mbuf->name)) {
 236                ret = -EEXIST;
 237                kfree(mbe);
 238                goto unlock;
 239        }
 240
 241        mbe->mbuf = mbuf;
 242        mbe->owner = owner;
 243        list_add_tail(&mbe->entry, &msu_buffer_list);
 244unlock:
 245        mutex_unlock(&msu_buffer_mutex);
 246
 247        return ret;
 248}
 249EXPORT_SYMBOL_GPL(intel_th_msu_buffer_register);
 250
 251void intel_th_msu_buffer_unregister(const struct msu_buffer *mbuf)
 252{
 253        struct msu_buffer_entry *mbe;
 254
 255        mutex_lock(&msu_buffer_mutex);
 256        mbe = __msu_buffer_entry_find(mbuf->name);
 257        if (mbe) {
 258                list_del(&mbe->entry);
 259                kfree(mbe);
 260        }
 261        mutex_unlock(&msu_buffer_mutex);
 262}
 263EXPORT_SYMBOL_GPL(intel_th_msu_buffer_unregister);
 264
 265static inline bool msc_block_is_empty(struct msc_block_desc *bdesc)
 266{
 267        /* header hasn't been written */
 268        if (!bdesc->valid_dw)
 269                return true;
 270
 271        /* valid_dw includes the header */
 272        if (!msc_data_sz(bdesc))
 273                return true;
 274
 275        return false;
 276}
 277
 278static inline struct scatterlist *msc_win_base_sg(struct msc_window *win)
 279{
 280        return win->sgt->sgl;
 281}
 282
 283static inline struct msc_block_desc *msc_win_base(struct msc_window *win)
 284{
 285        return sg_virt(msc_win_base_sg(win));
 286}
 287
 288static inline dma_addr_t msc_win_base_dma(struct msc_window *win)
 289{
 290        return sg_dma_address(msc_win_base_sg(win));
 291}
 292
 293static inline unsigned long
 294msc_win_base_pfn(struct msc_window *win)
 295{
 296        return PFN_DOWN(msc_win_base_dma(win));
 297}
 298
 299/**
 300 * msc_is_last_win() - check if a window is the last one for a given MSC
 301 * @win:        window
 302 * Return:      true if @win is the last window in MSC's multiblock buffer
 303 */
 304static inline bool msc_is_last_win(struct msc_window *win)
 305{
 306        return win->entry.next == &win->msc->win_list;
 307}
 308
 309/**
 310 * msc_next_window() - return next window in the multiblock buffer
 311 * @win:        current window
 312 *
 313 * Return:      window following the current one
 314 */
 315static struct msc_window *msc_next_window(struct msc_window *win)
 316{
 317        if (msc_is_last_win(win))
 318                return list_first_entry(&win->msc->win_list, struct msc_window,
 319                                        entry);
 320
 321        return list_next_entry(win, entry);
 322}
 323
 324static size_t msc_win_total_sz(struct msc_window *win)
 325{
 326        struct scatterlist *sg;
 327        unsigned int blk;
 328        size_t size = 0;
 329
 330        for_each_sg(win->sgt->sgl, sg, win->nr_segs, blk) {
 331                struct msc_block_desc *bdesc = sg_virt(sg);
 332
 333                if (msc_block_wrapped(bdesc))
 334                        return (size_t)win->nr_blocks << PAGE_SHIFT;
 335
 336                size += msc_total_sz(bdesc);
 337                if (msc_block_last_written(bdesc))
 338                        break;
 339        }
 340
 341        return size;
 342}
 343
 344/**
 345 * msc_find_window() - find a window matching a given sg_table
 346 * @msc:        MSC device
 347 * @sgt:        SG table of the window
 348 * @nonempty:   skip over empty windows
 349 *
 350 * Return:      MSC window structure pointer or NULL if the window
 351 *              could not be found.
 352 */
 353static struct msc_window *
 354msc_find_window(struct msc *msc, struct sg_table *sgt, bool nonempty)
 355{
 356        struct msc_window *win;
 357        unsigned int found = 0;
 358
 359        if (list_empty(&msc->win_list))
 360                return NULL;
 361
 362        /*
 363         * we might need a radix tree for this, depending on how
 364         * many windows a typical user would allocate; ideally it's
 365         * something like 2, in which case we're good
 366         */
 367        list_for_each_entry(win, &msc->win_list, entry) {
 368                if (win->sgt == sgt)
 369                        found++;
 370
 371                /* skip the empty ones */
 372                if (nonempty && msc_block_is_empty(msc_win_base(win)))
 373                        continue;
 374
 375                if (found)
 376                        return win;
 377        }
 378
 379        return NULL;
 380}
 381
 382/**
 383 * msc_oldest_window() - locate the window with oldest data
 384 * @msc:        MSC device
 385 *
 386 * This should only be used in multiblock mode. Caller should hold the
 387 * msc::user_count reference.
 388 *
 389 * Return:      the oldest window with valid data
 390 */
 391static struct msc_window *msc_oldest_window(struct msc *msc)
 392{
 393        struct msc_window *win;
 394
 395        if (list_empty(&msc->win_list))
 396                return NULL;
 397
 398        win = msc_find_window(msc, msc_next_window(msc->cur_win)->sgt, true);
 399        if (win)
 400                return win;
 401
 402        return list_first_entry(&msc->win_list, struct msc_window, entry);
 403}
 404
 405/**
 406 * msc_win_oldest_sg() - locate the oldest block in a given window
 407 * @win:        window to look at
 408 *
 409 * Return:      index of the block with the oldest data
 410 */
 411static struct scatterlist *msc_win_oldest_sg(struct msc_window *win)
 412{
 413        unsigned int blk;
 414        struct scatterlist *sg;
 415        struct msc_block_desc *bdesc = msc_win_base(win);
 416
 417        /* without wrapping, first block is the oldest */
 418        if (!msc_block_wrapped(bdesc))
 419                return msc_win_base_sg(win);
 420
 421        /*
 422         * with wrapping, last written block contains both the newest and the
 423         * oldest data for this window.
 424         */
 425        for_each_sg(win->sgt->sgl, sg, win->nr_segs, blk) {
 426                struct msc_block_desc *bdesc = sg_virt(sg);
 427
 428                if (msc_block_last_written(bdesc))
 429                        return sg;
 430        }
 431
 432        return msc_win_base_sg(win);
 433}
 434
 435static struct msc_block_desc *msc_iter_bdesc(struct msc_iter *iter)
 436{
 437        return sg_virt(iter->block);
 438}
 439
 440static struct msc_iter *msc_iter_install(struct msc *msc)
 441{
 442        struct msc_iter *iter;
 443
 444        iter = kzalloc(sizeof(*iter), GFP_KERNEL);
 445        if (!iter)
 446                return ERR_PTR(-ENOMEM);
 447
 448        mutex_lock(&msc->buf_mutex);
 449
 450        /*
 451         * Reading and tracing are mutually exclusive; if msc is
 452         * enabled, open() will fail; otherwise existing readers
 453         * will prevent enabling the msc and the rest of fops don't
 454         * need to worry about it.
 455         */
 456        if (msc->enabled) {
 457                kfree(iter);
 458                iter = ERR_PTR(-EBUSY);
 459                goto unlock;
 460        }
 461
 462        iter->msc = msc;
 463
 464        list_add_tail(&iter->entry, &msc->iter_list);
 465unlock:
 466        mutex_unlock(&msc->buf_mutex);
 467
 468        return iter;
 469}
 470
 471static void msc_iter_remove(struct msc_iter *iter, struct msc *msc)
 472{
 473        mutex_lock(&msc->buf_mutex);
 474        list_del(&iter->entry);
 475        mutex_unlock(&msc->buf_mutex);
 476
 477        kfree(iter);
 478}
 479
 480static void msc_iter_block_start(struct msc_iter *iter)
 481{
 482        if (iter->start_block)
 483                return;
 484
 485        iter->start_block = msc_win_oldest_sg(iter->win);
 486        iter->block = iter->start_block;
 487        iter->wrap_count = 0;
 488
 489        /*
 490         * start with the block with oldest data; if data has wrapped
 491         * in this window, it should be in this block
 492         */
 493        if (msc_block_wrapped(msc_iter_bdesc(iter)))
 494                iter->wrap_count = 2;
 495
 496}
 497
 498static int msc_iter_win_start(struct msc_iter *iter, struct msc *msc)
 499{
 500        /* already started, nothing to do */
 501        if (iter->start_win)
 502                return 0;
 503
 504        iter->start_win = msc_oldest_window(msc);
 505        if (!iter->start_win)
 506                return -EINVAL;
 507
 508        iter->win = iter->start_win;
 509        iter->start_block = NULL;
 510
 511        msc_iter_block_start(iter);
 512
 513        return 0;
 514}
 515
 516static int msc_iter_win_advance(struct msc_iter *iter)
 517{
 518        iter->win = msc_next_window(iter->win);
 519        iter->start_block = NULL;
 520
 521        if (iter->win == iter->start_win) {
 522                iter->eof++;
 523                return 1;
 524        }
 525
 526        msc_iter_block_start(iter);
 527
 528        return 0;
 529}
 530
 531static int msc_iter_block_advance(struct msc_iter *iter)
 532{
 533        iter->block_off = 0;
 534
 535        /* wrapping */
 536        if (iter->wrap_count && iter->block == iter->start_block) {
 537                iter->wrap_count--;
 538                if (!iter->wrap_count)
 539                        /* copied newest data from the wrapped block */
 540                        return msc_iter_win_advance(iter);
 541        }
 542
 543        /* no wrapping, check for last written block */
 544        if (!iter->wrap_count && msc_block_last_written(msc_iter_bdesc(iter)))
 545                /* copied newest data for the window */
 546                return msc_iter_win_advance(iter);
 547
 548        /* block advance */
 549        if (sg_is_last(iter->block))
 550                iter->block = msc_win_base_sg(iter->win);
 551        else
 552                iter->block = sg_next(iter->block);
 553
 554        /* no wrapping, sanity check in case there is no last written block */
 555        if (!iter->wrap_count && iter->block == iter->start_block)
 556                return msc_iter_win_advance(iter);
 557
 558        return 0;
 559}
 560
 561/**
 562 * msc_buffer_iterate() - go through multiblock buffer's data
 563 * @iter:       iterator structure
 564 * @size:       amount of data to scan
 565 * @data:       callback's private data
 566 * @fn:         iterator callback
 567 *
 568 * This will start at the window which will be written to next (containing
 569 * the oldest data) and work its way to the current window, calling @fn
 570 * for each chunk of data as it goes.
 571 *
 572 * Caller should have msc::user_count reference to make sure the buffer
 573 * doesn't disappear from under us.
 574 *
 575 * Return:      amount of data actually scanned.
 576 */
 577static ssize_t
 578msc_buffer_iterate(struct msc_iter *iter, size_t size, void *data,
 579                   unsigned long (*fn)(void *, void *, size_t))
 580{
 581        struct msc *msc = iter->msc;
 582        size_t len = size;
 583        unsigned int advance;
 584
 585        if (iter->eof)
 586                return 0;
 587
 588        /* start with the oldest window */
 589        if (msc_iter_win_start(iter, msc))
 590                return 0;
 591
 592        do {
 593                unsigned long data_bytes = msc_data_sz(msc_iter_bdesc(iter));
 594                void *src = (void *)msc_iter_bdesc(iter) + MSC_BDESC;
 595                size_t tocopy = data_bytes, copied = 0;
 596                size_t remaining = 0;
 597
 598                advance = 1;
 599
 600                /*
 601                 * If block wrapping happened, we need to visit the last block
 602                 * twice, because it contains both the oldest and the newest
 603                 * data in this window.
 604                 *
 605                 * First time (wrap_count==2), in the very beginning, to collect
 606                 * the oldest data, which is in the range
 607                 * (data_bytes..DATA_IN_PAGE).
 608                 *
 609                 * Second time (wrap_count==1), it's just like any other block,
 610                 * containing data in the range of [MSC_BDESC..data_bytes].
 611                 */
 612                if (iter->block == iter->start_block && iter->wrap_count == 2) {
 613                        tocopy = DATA_IN_PAGE - data_bytes;
 614                        src += data_bytes;
 615                }
 616
 617                if (!tocopy)
 618                        goto next_block;
 619
 620                tocopy -= iter->block_off;
 621                src += iter->block_off;
 622
 623                if (len < tocopy) {
 624                        tocopy = len;
 625                        advance = 0;
 626                }
 627
 628                remaining = fn(data, src, tocopy);
 629
 630                if (remaining)
 631                        advance = 0;
 632
 633                copied = tocopy - remaining;
 634                len -= copied;
 635                iter->block_off += copied;
 636                iter->offset += copied;
 637
 638                if (!advance)
 639                        break;
 640
 641next_block:
 642                if (msc_iter_block_advance(iter))
 643                        break;
 644
 645        } while (len);
 646
 647        return size - len;
 648}
 649
 650/**
 651 * msc_buffer_clear_hw_header() - clear hw header for multiblock
 652 * @msc:        MSC device
 653 */
 654static void msc_buffer_clear_hw_header(struct msc *msc)
 655{
 656        struct msc_window *win;
 657        struct scatterlist *sg;
 658
 659        list_for_each_entry(win, &msc->win_list, entry) {
 660                unsigned int blk;
 661                size_t hw_sz = sizeof(struct msc_block_desc) -
 662                        offsetof(struct msc_block_desc, hw_tag);
 663
 664                for_each_sg(win->sgt->sgl, sg, win->nr_segs, blk) {
 665                        struct msc_block_desc *bdesc = sg_virt(sg);
 666
 667                        memset(&bdesc->hw_tag, 0, hw_sz);
 668                }
 669        }
 670}
 671
 672static int intel_th_msu_init(struct msc *msc)
 673{
 674        u32 mintctl, msusts;
 675
 676        if (!msc->do_irq)
 677                return 0;
 678
 679        if (!msc->mbuf)
 680                return 0;
 681
 682        mintctl = ioread32(msc->msu_base + REG_MSU_MINTCTL);
 683        mintctl |= msc->index ? M1BLIE : M0BLIE;
 684        iowrite32(mintctl, msc->msu_base + REG_MSU_MINTCTL);
 685        if (mintctl != ioread32(msc->msu_base + REG_MSU_MINTCTL)) {
 686                dev_info(msc_dev(msc), "MINTCTL ignores writes: no usable interrupts\n");
 687                msc->do_irq = 0;
 688                return 0;
 689        }
 690
 691        msusts = ioread32(msc->msu_base + REG_MSU_MSUSTS);
 692        iowrite32(msusts, msc->msu_base + REG_MSU_MSUSTS);
 693
 694        return 0;
 695}
 696
 697static void intel_th_msu_deinit(struct msc *msc)
 698{
 699        u32 mintctl;
 700
 701        if (!msc->do_irq)
 702                return;
 703
 704        mintctl = ioread32(msc->msu_base + REG_MSU_MINTCTL);
 705        mintctl &= msc->index ? ~M1BLIE : ~M0BLIE;
 706        iowrite32(mintctl, msc->msu_base + REG_MSU_MINTCTL);
 707}
 708
 709static int msc_win_set_lockout(struct msc_window *win,
 710                               enum lockout_state expect,
 711                               enum lockout_state new)
 712{
 713        enum lockout_state old;
 714        unsigned long flags;
 715        int ret = 0;
 716
 717        if (!win->msc->mbuf)
 718                return 0;
 719
 720        spin_lock_irqsave(&win->lo_lock, flags);
 721        old = win->lockout;
 722
 723        if (old != expect) {
 724                ret = -EINVAL;
 725                goto unlock;
 726        }
 727
 728        win->lockout = new;
 729
 730        if (old == expect && new == WIN_LOCKED)
 731                atomic_inc(&win->msc->user_count);
 732        else if (old == expect && old == WIN_LOCKED)
 733                atomic_dec(&win->msc->user_count);
 734
 735unlock:
 736        spin_unlock_irqrestore(&win->lo_lock, flags);
 737
 738        if (ret) {
 739                if (expect == WIN_READY && old == WIN_LOCKED)
 740                        return -EBUSY;
 741
 742                /* from intel_th_msc_window_unlock(), don't warn if not locked */
 743                if (expect == WIN_LOCKED && old == new)
 744                        return 0;
 745
 746                dev_warn_ratelimited(msc_dev(win->msc),
 747                                     "expected lockout state %d, got %d\n",
 748                                     expect, old);
 749        }
 750
 751        return ret;
 752}
 753/**
 754 * msc_configure() - set up MSC hardware
 755 * @msc:        the MSC device to configure
 756 *
 757 * Program storage mode, wrapping, burst length and trace buffer address
 758 * into a given MSC. Then, enable tracing and set msc::enabled.
 759 * The latter is serialized on msc::buf_mutex, so make sure to hold it.
 760 */
 761static int msc_configure(struct msc *msc)
 762{
 763        u32 reg;
 764
 765        lockdep_assert_held(&msc->buf_mutex);
 766
 767        if (msc->mode > MSC_MODE_MULTI)
 768                return -EINVAL;
 769
 770        if (msc->mode == MSC_MODE_MULTI) {
 771                if (msc_win_set_lockout(msc->cur_win, WIN_READY, WIN_INUSE))
 772                        return -EBUSY;
 773
 774                msc_buffer_clear_hw_header(msc);
 775        }
 776
 777        msc->orig_addr = ioread32(msc->reg_base + REG_MSU_MSC0BAR);
 778        msc->orig_sz   = ioread32(msc->reg_base + REG_MSU_MSC0SIZE);
 779
 780        reg = msc->base_addr >> PAGE_SHIFT;
 781        iowrite32(reg, msc->reg_base + REG_MSU_MSC0BAR);
 782
 783        if (msc->mode == MSC_MODE_SINGLE) {
 784                reg = msc->nr_pages;
 785                iowrite32(reg, msc->reg_base + REG_MSU_MSC0SIZE);
 786        }
 787
 788        reg = ioread32(msc->reg_base + REG_MSU_MSC0CTL);
 789        reg &= ~(MSC_MODE | MSC_WRAPEN | MSC_EN | MSC_RD_HDR_OVRD);
 790
 791        reg |= MSC_EN;
 792        reg |= msc->mode << __ffs(MSC_MODE);
 793        reg |= msc->burst_len << __ffs(MSC_LEN);
 794
 795        if (msc->wrap)
 796                reg |= MSC_WRAPEN;
 797
 798        iowrite32(reg, msc->reg_base + REG_MSU_MSC0CTL);
 799
 800        intel_th_msu_init(msc);
 801
 802        msc->thdev->output.multiblock = msc->mode == MSC_MODE_MULTI;
 803        intel_th_trace_enable(msc->thdev);
 804        msc->enabled = 1;
 805
 806        if (msc->mbuf && msc->mbuf->activate)
 807                msc->mbuf->activate(msc->mbuf_priv);
 808
 809        return 0;
 810}
 811
 812/**
 813 * msc_disable() - disable MSC hardware
 814 * @msc:        MSC device to disable
 815 *
 816 * If @msc is enabled, disable tracing on the switch and then disable MSC
 817 * storage. Caller must hold msc::buf_mutex.
 818 */
 819static void msc_disable(struct msc *msc)
 820{
 821        struct msc_window *win = msc->cur_win;
 822        u32 reg;
 823
 824        lockdep_assert_held(&msc->buf_mutex);
 825
 826        if (msc->mode == MSC_MODE_MULTI)
 827                msc_win_set_lockout(win, WIN_INUSE, WIN_LOCKED);
 828
 829        if (msc->mbuf && msc->mbuf->deactivate)
 830                msc->mbuf->deactivate(msc->mbuf_priv);
 831        intel_th_msu_deinit(msc);
 832        intel_th_trace_disable(msc->thdev);
 833
 834        if (msc->mode == MSC_MODE_SINGLE) {
 835                reg = ioread32(msc->reg_base + REG_MSU_MSC0STS);
 836                msc->single_wrap = !!(reg & MSCSTS_WRAPSTAT);
 837
 838                reg = ioread32(msc->reg_base + REG_MSU_MSC0MWP);
 839                msc->single_sz = reg & ((msc->nr_pages << PAGE_SHIFT) - 1);
 840                dev_dbg(msc_dev(msc), "MSCnMWP: %08x/%08lx, wrap: %d\n",
 841                        reg, msc->single_sz, msc->single_wrap);
 842        }
 843
 844        reg = ioread32(msc->reg_base + REG_MSU_MSC0CTL);
 845        reg &= ~MSC_EN;
 846        iowrite32(reg, msc->reg_base + REG_MSU_MSC0CTL);
 847
 848        if (msc->mbuf && msc->mbuf->ready)
 849                msc->mbuf->ready(msc->mbuf_priv, win->sgt,
 850                                 msc_win_total_sz(win));
 851
 852        msc->enabled = 0;
 853
 854        iowrite32(msc->orig_addr, msc->reg_base + REG_MSU_MSC0BAR);
 855        iowrite32(msc->orig_sz, msc->reg_base + REG_MSU_MSC0SIZE);
 856
 857        dev_dbg(msc_dev(msc), "MSCnNWSA: %08x\n",
 858                ioread32(msc->reg_base + REG_MSU_MSC0NWSA));
 859
 860        reg = ioread32(msc->reg_base + REG_MSU_MSC0STS);
 861        dev_dbg(msc_dev(msc), "MSCnSTS: %08x\n", reg);
 862
 863        reg = ioread32(msc->reg_base + REG_MSU_MSUSTS);
 864        reg &= msc->index ? MSUSTS_MSC1BLAST : MSUSTS_MSC0BLAST;
 865        iowrite32(reg, msc->reg_base + REG_MSU_MSUSTS);
 866}
 867
 868static int intel_th_msc_activate(struct intel_th_device *thdev)
 869{
 870        struct msc *msc = dev_get_drvdata(&thdev->dev);
 871        int ret = -EBUSY;
 872
 873        if (!atomic_inc_unless_negative(&msc->user_count))
 874                return -ENODEV;
 875
 876        mutex_lock(&msc->buf_mutex);
 877
 878        /* if there are readers, refuse */
 879        if (list_empty(&msc->iter_list))
 880                ret = msc_configure(msc);
 881
 882        mutex_unlock(&msc->buf_mutex);
 883
 884        if (ret)
 885                atomic_dec(&msc->user_count);
 886
 887        return ret;
 888}
 889
 890static void intel_th_msc_deactivate(struct intel_th_device *thdev)
 891{
 892        struct msc *msc = dev_get_drvdata(&thdev->dev);
 893
 894        mutex_lock(&msc->buf_mutex);
 895        if (msc->enabled) {
 896                msc_disable(msc);
 897                atomic_dec(&msc->user_count);
 898        }
 899        mutex_unlock(&msc->buf_mutex);
 900}
 901
 902/**
 903 * msc_buffer_contig_alloc() - allocate a contiguous buffer for SINGLE mode
 904 * @msc:        MSC device
 905 * @size:       allocation size in bytes
 906 *
 907 * This modifies msc::base, which requires msc::buf_mutex to serialize, so the
 908 * caller is expected to hold it.
 909 *
 910 * Return:      0 on success, -errno otherwise.
 911 */
 912static int msc_buffer_contig_alloc(struct msc *msc, unsigned long size)
 913{
 914        unsigned long nr_pages = size >> PAGE_SHIFT;
 915        unsigned int order = get_order(size);
 916        struct page *page;
 917        int ret;
 918
 919        if (!size)
 920                return 0;
 921
 922        ret = sg_alloc_table(&msc->single_sgt, 1, GFP_KERNEL);
 923        if (ret)
 924                goto err_out;
 925
 926        ret = -ENOMEM;
 927        page = alloc_pages(GFP_KERNEL | __GFP_ZERO | GFP_DMA32, order);
 928        if (!page)
 929                goto err_free_sgt;
 930
 931        split_page(page, order);
 932        sg_set_buf(msc->single_sgt.sgl, page_address(page), size);
 933
 934        ret = dma_map_sg(msc_dev(msc)->parent->parent, msc->single_sgt.sgl, 1,
 935                         DMA_FROM_DEVICE);
 936        if (ret < 0)
 937                goto err_free_pages;
 938
 939        msc->nr_pages = nr_pages;
 940        msc->base = page_address(page);
 941        msc->base_addr = sg_dma_address(msc->single_sgt.sgl);
 942
 943        return 0;
 944
 945err_free_pages:
 946        __free_pages(page, order);
 947
 948err_free_sgt:
 949        sg_free_table(&msc->single_sgt);
 950
 951err_out:
 952        return ret;
 953}
 954
 955/**
 956 * msc_buffer_contig_free() - free a contiguous buffer
 957 * @msc:        MSC configured in SINGLE mode
 958 */
 959static void msc_buffer_contig_free(struct msc *msc)
 960{
 961        unsigned long off;
 962
 963        dma_unmap_sg(msc_dev(msc)->parent->parent, msc->single_sgt.sgl,
 964                     1, DMA_FROM_DEVICE);
 965        sg_free_table(&msc->single_sgt);
 966
 967        for (off = 0; off < msc->nr_pages << PAGE_SHIFT; off += PAGE_SIZE) {
 968                struct page *page = virt_to_page(msc->base + off);
 969
 970                page->mapping = NULL;
 971                __free_page(page);
 972        }
 973
 974        msc->nr_pages = 0;
 975}
 976
 977/**
 978 * msc_buffer_contig_get_page() - find a page at a given offset
 979 * @msc:        MSC configured in SINGLE mode
 980 * @pgoff:      page offset
 981 *
 982 * Return:      page, if @pgoff is within the range, NULL otherwise.
 983 */
 984static struct page *msc_buffer_contig_get_page(struct msc *msc,
 985                                               unsigned long pgoff)
 986{
 987        if (pgoff >= msc->nr_pages)
 988                return NULL;
 989
 990        return virt_to_page(msc->base + (pgoff << PAGE_SHIFT));
 991}
 992
 993static int __msc_buffer_win_alloc(struct msc_window *win,
 994                                  unsigned int nr_segs)
 995{
 996        struct scatterlist *sg_ptr;
 997        void *block;
 998        int i, ret;
 999
1000        ret = sg_alloc_table(win->sgt, nr_segs, GFP_KERNEL);
1001        if (ret)
1002                return -ENOMEM;
1003
1004        for_each_sg(win->sgt->sgl, sg_ptr, nr_segs, i) {
1005                block = dma_alloc_coherent(msc_dev(win->msc)->parent->parent,
1006                                          PAGE_SIZE, &sg_dma_address(sg_ptr),
1007                                          GFP_KERNEL);
1008                if (!block)
1009                        goto err_nomem;
1010
1011                sg_set_buf(sg_ptr, block, PAGE_SIZE);
1012        }
1013
1014        return nr_segs;
1015
1016err_nomem:
1017        for_each_sg(win->sgt->sgl, sg_ptr, i, ret)
1018                dma_free_coherent(msc_dev(win->msc)->parent->parent, PAGE_SIZE,
1019                                  sg_virt(sg_ptr), sg_dma_address(sg_ptr));
1020
1021        sg_free_table(win->sgt);
1022
1023        return -ENOMEM;
1024}
1025
1026#ifdef CONFIG_X86
1027static void msc_buffer_set_uc(struct msc *msc)
1028{
1029        struct scatterlist *sg_ptr;
1030        struct msc_window *win;
1031        int i;
1032
1033        if (msc->mode == MSC_MODE_SINGLE) {
1034                set_memory_uc((unsigned long)msc->base, msc->nr_pages);
1035                return;
1036        }
1037
1038        list_for_each_entry(win, &msc->win_list, entry) {
1039                for_each_sg(win->sgt->sgl, sg_ptr, win->nr_segs, i) {
1040                        /* Set the page as uncached */
1041                        set_memory_uc((unsigned long)sg_virt(sg_ptr),
1042                                        PFN_DOWN(sg_ptr->length));
1043                }
1044        }
1045}
1046
1047static void msc_buffer_set_wb(struct msc *msc)
1048{
1049        struct scatterlist *sg_ptr;
1050        struct msc_window *win;
1051        int i;
1052
1053        if (msc->mode == MSC_MODE_SINGLE) {
1054                set_memory_wb((unsigned long)msc->base, msc->nr_pages);
1055                return;
1056        }
1057
1058        list_for_each_entry(win, &msc->win_list, entry) {
1059                for_each_sg(win->sgt->sgl, sg_ptr, win->nr_segs, i) {
1060                        /* Reset the page to write-back */
1061                        set_memory_wb((unsigned long)sg_virt(sg_ptr),
1062                                        PFN_DOWN(sg_ptr->length));
1063                }
1064        }
1065}
1066#else /* !X86 */
1067static inline void
1068msc_buffer_set_uc(struct msc *msc) {}
1069static inline void msc_buffer_set_wb(struct msc *msc) {}
1070#endif /* CONFIG_X86 */
1071
1072/**
1073 * msc_buffer_win_alloc() - alloc a window for a multiblock mode
1074 * @msc:        MSC device
1075 * @nr_blocks:  number of pages in this window
1076 *
1077 * This modifies msc::win_list and msc::base, which requires msc::buf_mutex
1078 * to serialize, so the caller is expected to hold it.
1079 *
1080 * Return:      0 on success, -errno otherwise.
1081 */
1082static int msc_buffer_win_alloc(struct msc *msc, unsigned int nr_blocks)
1083{
1084        struct msc_window *win;
1085        int ret = -ENOMEM;
1086
1087        if (!nr_blocks)
1088                return 0;
1089
1090        win = kzalloc(sizeof(*win), GFP_KERNEL);
1091        if (!win)
1092                return -ENOMEM;
1093
1094        win->msc = msc;
1095        win->sgt = &win->_sgt;
1096        win->lockout = WIN_READY;
1097        spin_lock_init(&win->lo_lock);
1098
1099        if (!list_empty(&msc->win_list)) {
1100                struct msc_window *prev = list_last_entry(&msc->win_list,
1101                                                          struct msc_window,
1102                                                          entry);
1103
1104                win->pgoff = prev->pgoff + prev->nr_blocks;
1105        }
1106
1107        if (msc->mbuf && msc->mbuf->alloc_window)
1108                ret = msc->mbuf->alloc_window(msc->mbuf_priv, &win->sgt,
1109                                              nr_blocks << PAGE_SHIFT);
1110        else
1111                ret = __msc_buffer_win_alloc(win, nr_blocks);
1112
1113        if (ret <= 0)
1114                goto err_nomem;
1115
1116        win->nr_segs = ret;
1117        win->nr_blocks = nr_blocks;
1118
1119        if (list_empty(&msc->win_list)) {
1120                msc->base = msc_win_base(win);
1121                msc->base_addr = msc_win_base_dma(win);
1122                msc->cur_win = win;
1123        }
1124
1125        list_add_tail(&win->entry, &msc->win_list);
1126        msc->nr_pages += nr_blocks;
1127
1128        return 0;
1129
1130err_nomem:
1131        kfree(win);
1132
1133        return ret;
1134}
1135
1136static void __msc_buffer_win_free(struct msc *msc, struct msc_window *win)
1137{
1138        struct scatterlist *sg;
1139        int i;
1140
1141        for_each_sg(win->sgt->sgl, sg, win->nr_segs, i) {
1142                struct page *page = sg_page(sg);
1143
1144                page->mapping = NULL;
1145                dma_free_coherent(msc_dev(win->msc)->parent->parent, PAGE_SIZE,
1146                                  sg_virt(sg), sg_dma_address(sg));
1147        }
1148        sg_free_table(win->sgt);
1149}
1150
1151/**
1152 * msc_buffer_win_free() - free a window from MSC's window list
1153 * @msc:        MSC device
1154 * @win:        window to free
1155 *
1156 * This modifies msc::win_list and msc::base, which requires msc::buf_mutex
1157 * to serialize, so the caller is expected to hold it.
1158 */
1159static void msc_buffer_win_free(struct msc *msc, struct msc_window *win)
1160{
1161        msc->nr_pages -= win->nr_blocks;
1162
1163        list_del(&win->entry);
1164        if (list_empty(&msc->win_list)) {
1165                msc->base = NULL;
1166                msc->base_addr = 0;
1167        }
1168
1169        if (msc->mbuf && msc->mbuf->free_window)
1170                msc->mbuf->free_window(msc->mbuf_priv, win->sgt);
1171        else
1172                __msc_buffer_win_free(msc, win);
1173
1174        kfree(win);
1175}
1176
1177/**
1178 * msc_buffer_relink() - set up block descriptors for multiblock mode
1179 * @msc:        MSC device
1180 *
1181 * This traverses msc::win_list, which requires msc::buf_mutex to serialize,
1182 * so the caller is expected to hold it.
1183 */
1184static void msc_buffer_relink(struct msc *msc)
1185{
1186        struct msc_window *win, *next_win;
1187
1188        /* call with msc::mutex locked */
1189        list_for_each_entry(win, &msc->win_list, entry) {
1190                struct scatterlist *sg;
1191                unsigned int blk;
1192                u32 sw_tag = 0;
1193
1194                /*
1195                 * Last window's next_win should point to the first window
1196                 * and MSC_SW_TAG_LASTWIN should be set.
1197                 */
1198                if (msc_is_last_win(win)) {
1199                        sw_tag |= MSC_SW_TAG_LASTWIN;
1200                        next_win = list_first_entry(&msc->win_list,
1201                                                    struct msc_window, entry);
1202                } else {
1203                        next_win = list_next_entry(win, entry);
1204                }
1205
1206                for_each_sg(win->sgt->sgl, sg, win->nr_segs, blk) {
1207                        struct msc_block_desc *bdesc = sg_virt(sg);
1208
1209                        memset(bdesc, 0, sizeof(*bdesc));
1210
1211                        bdesc->next_win = msc_win_base_pfn(next_win);
1212
1213                        /*
1214                         * Similarly to last window, last block should point
1215                         * to the first one.
1216                         */
1217                        if (blk == win->nr_segs - 1) {
1218                                sw_tag |= MSC_SW_TAG_LASTBLK;
1219                                bdesc->next_blk = msc_win_base_pfn(win);
1220                        } else {
1221                                dma_addr_t addr = sg_dma_address(sg_next(sg));
1222
1223                                bdesc->next_blk = PFN_DOWN(addr);
1224                        }
1225
1226                        bdesc->sw_tag = sw_tag;
1227                        bdesc->block_sz = sg->length / 64;
1228                }
1229        }
1230
1231        /*
1232         * Make the above writes globally visible before tracing is
1233         * enabled to make sure hardware sees them coherently.
1234         */
1235        wmb();
1236}
1237
1238static void msc_buffer_multi_free(struct msc *msc)
1239{
1240        struct msc_window *win, *iter;
1241
1242        list_for_each_entry_safe(win, iter, &msc->win_list, entry)
1243                msc_buffer_win_free(msc, win);
1244}
1245
1246static int msc_buffer_multi_alloc(struct msc *msc, unsigned long *nr_pages,
1247                                  unsigned int nr_wins)
1248{
1249        int ret, i;
1250
1251        for (i = 0; i < nr_wins; i++) {
1252                ret = msc_buffer_win_alloc(msc, nr_pages[i]);
1253                if (ret) {
1254                        msc_buffer_multi_free(msc);
1255                        return ret;
1256                }
1257        }
1258
1259        msc_buffer_relink(msc);
1260
1261        return 0;
1262}
1263
1264/**
1265 * msc_buffer_free() - free buffers for MSC
1266 * @msc:        MSC device
1267 *
1268 * Free MSC's storage buffers.
1269 *
1270 * This modifies msc::win_list and msc::base, which requires msc::buf_mutex to
1271 * serialize, so the caller is expected to hold it.
1272 */
1273static void msc_buffer_free(struct msc *msc)
1274{
1275        msc_buffer_set_wb(msc);
1276
1277        if (msc->mode == MSC_MODE_SINGLE)
1278                msc_buffer_contig_free(msc);
1279        else if (msc->mode == MSC_MODE_MULTI)
1280                msc_buffer_multi_free(msc);
1281}
1282
1283/**
1284 * msc_buffer_alloc() - allocate a buffer for MSC
1285 * @msc:        MSC device
1286 * @size:       allocation size in bytes
1287 *
1288 * Allocate a storage buffer for MSC, depending on the msc::mode, it will be
1289 * either done via msc_buffer_contig_alloc() for SINGLE operation mode or
1290 * msc_buffer_win_alloc() for multiblock operation. The latter allocates one
1291 * window per invocation, so in multiblock mode this can be called multiple
1292 * times for the same MSC to allocate multiple windows.
1293 *
1294 * This modifies msc::win_list and msc::base, which requires msc::buf_mutex
1295 * to serialize, so the caller is expected to hold it.
1296 *
1297 * Return:      0 on success, -errno otherwise.
1298 */
1299static int msc_buffer_alloc(struct msc *msc, unsigned long *nr_pages,
1300                            unsigned int nr_wins)
1301{
1302        int ret;
1303
1304        /* -1: buffer not allocated */
1305        if (atomic_read(&msc->user_count) != -1)
1306                return -EBUSY;
1307
1308        if (msc->mode == MSC_MODE_SINGLE) {
1309                if (nr_wins != 1)
1310                        return -EINVAL;
1311
1312                ret = msc_buffer_contig_alloc(msc, nr_pages[0] << PAGE_SHIFT);
1313        } else if (msc->mode == MSC_MODE_MULTI) {
1314                ret = msc_buffer_multi_alloc(msc, nr_pages, nr_wins);
1315        } else {
1316                ret = -EINVAL;
1317        }
1318
1319        if (!ret) {
1320                msc_buffer_set_uc(msc);
1321
1322                /* allocation should be visible before the counter goes to 0 */
1323                smp_mb__before_atomic();
1324
1325                if (WARN_ON_ONCE(atomic_cmpxchg(&msc->user_count, -1, 0) != -1))
1326                        return -EINVAL;
1327        }
1328
1329        return ret;
1330}
1331
1332/**
1333 * msc_buffer_unlocked_free_unless_used() - free a buffer unless it's in use
1334 * @msc:        MSC device
1335 *
1336 * This will free MSC buffer unless it is in use or there is no allocated
1337 * buffer.
1338 * Caller needs to hold msc::buf_mutex.
1339 *
1340 * Return:      0 on successful deallocation or if there was no buffer to
1341 *              deallocate, -EBUSY if there are active users.
1342 */
1343static int msc_buffer_unlocked_free_unless_used(struct msc *msc)
1344{
1345        int count, ret = 0;
1346
1347        count = atomic_cmpxchg(&msc->user_count, 0, -1);
1348
1349        /* > 0: buffer is allocated and has users */
1350        if (count > 0)
1351                ret = -EBUSY;
1352        /* 0: buffer is allocated, no users */
1353        else if (!count)
1354                msc_buffer_free(msc);
1355        /* < 0: no buffer, nothing to do */
1356
1357        return ret;
1358}
1359
1360/**
1361 * msc_buffer_free_unless_used() - free a buffer unless it's in use
1362 * @msc:        MSC device
1363 *
1364 * This is a locked version of msc_buffer_unlocked_free_unless_used().
1365 */
1366static int msc_buffer_free_unless_used(struct msc *msc)
1367{
1368        int ret;
1369
1370        mutex_lock(&msc->buf_mutex);
1371        ret = msc_buffer_unlocked_free_unless_used(msc);
1372        mutex_unlock(&msc->buf_mutex);
1373
1374        return ret;
1375}
1376
1377/**
1378 * msc_buffer_get_page() - get MSC buffer page at a given offset
1379 * @msc:        MSC device
1380 * @pgoff:      page offset into the storage buffer
1381 *
1382 * This traverses msc::win_list, so holding msc::buf_mutex is expected from
1383 * the caller.
1384 *
1385 * Return:      page if @pgoff corresponds to a valid buffer page or NULL.
1386 */
1387static struct page *msc_buffer_get_page(struct msc *msc, unsigned long pgoff)
1388{
1389        struct msc_window *win;
1390        struct scatterlist *sg;
1391        unsigned int blk;
1392
1393        if (msc->mode == MSC_MODE_SINGLE)
1394                return msc_buffer_contig_get_page(msc, pgoff);
1395
1396        list_for_each_entry(win, &msc->win_list, entry)
1397                if (pgoff >= win->pgoff && pgoff < win->pgoff + win->nr_blocks)
1398                        goto found;
1399
1400        return NULL;
1401
1402found:
1403        pgoff -= win->pgoff;
1404
1405        for_each_sg(win->sgt->sgl, sg, win->nr_segs, blk) {
1406                struct page *page = sg_page(sg);
1407                size_t pgsz = PFN_DOWN(sg->length);
1408
1409                if (pgoff < pgsz)
1410                        return page + pgoff;
1411
1412                pgoff -= pgsz;
1413        }
1414
1415        return NULL;
1416}
1417
1418/**
1419 * struct msc_win_to_user_struct - data for copy_to_user() callback
1420 * @buf:        userspace buffer to copy data to
1421 * @offset:     running offset
1422 */
1423struct msc_win_to_user_struct {
1424        char __user     *buf;
1425        unsigned long   offset;
1426};
1427
1428/**
1429 * msc_win_to_user() - iterator for msc_buffer_iterate() to copy data to user
1430 * @data:       callback's private data
1431 * @src:        source buffer
1432 * @len:        amount of data to copy from the source buffer
1433 */
1434static unsigned long msc_win_to_user(void *data, void *src, size_t len)
1435{
1436        struct msc_win_to_user_struct *u = data;
1437        unsigned long ret;
1438
1439        ret = copy_to_user(u->buf + u->offset, src, len);
1440        u->offset += len - ret;
1441
1442        return ret;
1443}
1444
1445
1446/*
1447 * file operations' callbacks
1448 */
1449
1450static int intel_th_msc_open(struct inode *inode, struct file *file)
1451{
1452        struct intel_th_device *thdev = file->private_data;
1453        struct msc *msc = dev_get_drvdata(&thdev->dev);
1454        struct msc_iter *iter;
1455
1456        if (!capable(CAP_SYS_RAWIO))
1457                return -EPERM;
1458
1459        iter = msc_iter_install(msc);
1460        if (IS_ERR(iter))
1461                return PTR_ERR(iter);
1462
1463        file->private_data = iter;
1464
1465        return nonseekable_open(inode, file);
1466}
1467
1468static int intel_th_msc_release(struct inode *inode, struct file *file)
1469{
1470        struct msc_iter *iter = file->private_data;
1471        struct msc *msc = iter->msc;
1472
1473        msc_iter_remove(iter, msc);
1474
1475        return 0;
1476}
1477
1478static ssize_t
1479msc_single_to_user(struct msc *msc, char __user *buf, loff_t off, size_t len)
1480{
1481        unsigned long size = msc->nr_pages << PAGE_SHIFT, rem = len;
1482        unsigned long start = off, tocopy = 0;
1483
1484        if (msc->single_wrap) {
1485                start += msc->single_sz;
1486                if (start < size) {
1487                        tocopy = min(rem, size - start);
1488                        if (copy_to_user(buf, msc->base + start, tocopy))
1489                                return -EFAULT;
1490
1491                        buf += tocopy;
1492                        rem -= tocopy;
1493                        start += tocopy;
1494                }
1495
1496                start &= size - 1;
1497                if (rem) {
1498                        tocopy = min(rem, msc->single_sz - start);
1499                        if (copy_to_user(buf, msc->base + start, tocopy))
1500                                return -EFAULT;
1501
1502                        rem -= tocopy;
1503                }
1504
1505                return len - rem;
1506        }
1507
1508        if (copy_to_user(buf, msc->base + start, rem))
1509                return -EFAULT;
1510
1511        return len;
1512}
1513
1514static ssize_t intel_th_msc_read(struct file *file, char __user *buf,
1515                                 size_t len, loff_t *ppos)
1516{
1517        struct msc_iter *iter = file->private_data;
1518        struct msc *msc = iter->msc;
1519        size_t size;
1520        loff_t off = *ppos;
1521        ssize_t ret = 0;
1522
1523        if (!atomic_inc_unless_negative(&msc->user_count))
1524                return 0;
1525
1526        if (msc->mode == MSC_MODE_SINGLE && !msc->single_wrap)
1527                size = msc->single_sz;
1528        else
1529                size = msc->nr_pages << PAGE_SHIFT;
1530
1531        if (!size)
1532                goto put_count;
1533
1534        if (off >= size)
1535                goto put_count;
1536
1537        if (off + len >= size)
1538                len = size - off;
1539
1540        if (msc->mode == MSC_MODE_SINGLE) {
1541                ret = msc_single_to_user(msc, buf, off, len);
1542                if (ret >= 0)
1543                        *ppos += ret;
1544        } else if (msc->mode == MSC_MODE_MULTI) {
1545                struct msc_win_to_user_struct u = {
1546                        .buf    = buf,
1547                        .offset = 0,
1548                };
1549
1550                ret = msc_buffer_iterate(iter, len, &u, msc_win_to_user);
1551                if (ret >= 0)
1552                        *ppos = iter->offset;
1553        } else {
1554                ret = -EINVAL;
1555        }
1556
1557put_count:
1558        atomic_dec(&msc->user_count);
1559
1560        return ret;
1561}
1562
1563/*
1564 * vm operations callbacks (vm_ops)
1565 */
1566
1567static void msc_mmap_open(struct vm_area_struct *vma)
1568{
1569        struct msc_iter *iter = vma->vm_file->private_data;
1570        struct msc *msc = iter->msc;
1571
1572        atomic_inc(&msc->mmap_count);
1573}
1574
1575static void msc_mmap_close(struct vm_area_struct *vma)
1576{
1577        struct msc_iter *iter = vma->vm_file->private_data;
1578        struct msc *msc = iter->msc;
1579        unsigned long pg;
1580
1581        if (!atomic_dec_and_mutex_lock(&msc->mmap_count, &msc->buf_mutex))
1582                return;
1583
1584        /* drop page _refcounts */
1585        for (pg = 0; pg < msc->nr_pages; pg++) {
1586                struct page *page = msc_buffer_get_page(msc, pg);
1587
1588                if (WARN_ON_ONCE(!page))
1589                        continue;
1590
1591                if (page->mapping)
1592                        page->mapping = NULL;
1593        }
1594
1595        /* last mapping -- drop user_count */
1596        atomic_dec(&msc->user_count);
1597        mutex_unlock(&msc->buf_mutex);
1598}
1599
1600static vm_fault_t msc_mmap_fault(struct vm_fault *vmf)
1601{
1602        struct msc_iter *iter = vmf->vma->vm_file->private_data;
1603        struct msc *msc = iter->msc;
1604
1605        vmf->page = msc_buffer_get_page(msc, vmf->pgoff);
1606        if (!vmf->page)
1607                return VM_FAULT_SIGBUS;
1608
1609        get_page(vmf->page);
1610        vmf->page->mapping = vmf->vma->vm_file->f_mapping;
1611        vmf->page->index = vmf->pgoff;
1612
1613        return 0;
1614}
1615
1616static const struct vm_operations_struct msc_mmap_ops = {
1617        .open   = msc_mmap_open,
1618        .close  = msc_mmap_close,
1619        .fault  = msc_mmap_fault,
1620};
1621
1622static int intel_th_msc_mmap(struct file *file, struct vm_area_struct *vma)
1623{
1624        unsigned long size = vma->vm_end - vma->vm_start;
1625        struct msc_iter *iter = vma->vm_file->private_data;
1626        struct msc *msc = iter->msc;
1627        int ret = -EINVAL;
1628
1629        if (!size || offset_in_page(size))
1630                return -EINVAL;
1631
1632        if (vma->vm_pgoff)
1633                return -EINVAL;
1634
1635        /* grab user_count once per mmap; drop in msc_mmap_close() */
1636        if (!atomic_inc_unless_negative(&msc->user_count))
1637                return -EINVAL;
1638
1639        if (msc->mode != MSC_MODE_SINGLE &&
1640            msc->mode != MSC_MODE_MULTI)
1641                goto out;
1642
1643        if (size >> PAGE_SHIFT != msc->nr_pages)
1644                goto out;
1645
1646        atomic_set(&msc->mmap_count, 1);
1647        ret = 0;
1648
1649out:
1650        if (ret)
1651                atomic_dec(&msc->user_count);
1652
1653        vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
1654        vma->vm_flags |= VM_DONTEXPAND | VM_DONTCOPY;
1655        vma->vm_ops = &msc_mmap_ops;
1656        return ret;
1657}
1658
1659static const struct file_operations intel_th_msc_fops = {
1660        .open           = intel_th_msc_open,
1661        .release        = intel_th_msc_release,
1662        .read           = intel_th_msc_read,
1663        .mmap           = intel_th_msc_mmap,
1664        .llseek         = no_llseek,
1665        .owner          = THIS_MODULE,
1666};
1667
1668static void intel_th_msc_wait_empty(struct intel_th_device *thdev)
1669{
1670        struct msc *msc = dev_get_drvdata(&thdev->dev);
1671        unsigned long count;
1672        u32 reg;
1673
1674        for (reg = 0, count = MSC_PLE_WAITLOOP_DEPTH;
1675             count && !(reg & MSCSTS_PLE); count--) {
1676                reg = __raw_readl(msc->reg_base + REG_MSU_MSC0STS);
1677                cpu_relax();
1678        }
1679
1680        if (!count)
1681                dev_dbg(msc_dev(msc), "timeout waiting for MSC0 PLE\n");
1682}
1683
1684static int intel_th_msc_init(struct msc *msc)
1685{
1686        atomic_set(&msc->user_count, -1);
1687
1688        msc->mode = msc->multi_is_broken ? MSC_MODE_SINGLE : MSC_MODE_MULTI;
1689        mutex_init(&msc->buf_mutex);
1690        INIT_LIST_HEAD(&msc->win_list);
1691        INIT_LIST_HEAD(&msc->iter_list);
1692
1693        msc->burst_len =
1694                (ioread32(msc->reg_base + REG_MSU_MSC0CTL) & MSC_LEN) >>
1695                __ffs(MSC_LEN);
1696
1697        return 0;
1698}
1699
1700static int msc_win_switch(struct msc *msc)
1701{
1702        struct msc_window *first;
1703
1704        if (list_empty(&msc->win_list))
1705                return -EINVAL;
1706
1707        first = list_first_entry(&msc->win_list, struct msc_window, entry);
1708
1709        if (msc_is_last_win(msc->cur_win))
1710                msc->cur_win = first;
1711        else
1712                msc->cur_win = list_next_entry(msc->cur_win, entry);
1713
1714        msc->base = msc_win_base(msc->cur_win);
1715        msc->base_addr = msc_win_base_dma(msc->cur_win);
1716
1717        intel_th_trace_switch(msc->thdev);
1718
1719        return 0;
1720}
1721
1722/**
1723 * intel_th_msc_window_unlock - put the window back in rotation
1724 * @dev:        MSC device to which this relates
1725 * @sgt:        buffer's sg_table for the window, does nothing if NULL
1726 */
1727void intel_th_msc_window_unlock(struct device *dev, struct sg_table *sgt)
1728{
1729        struct msc *msc = dev_get_drvdata(dev);
1730        struct msc_window *win;
1731
1732        if (!sgt)
1733                return;
1734
1735        win = msc_find_window(msc, sgt, false);
1736        if (!win)
1737                return;
1738
1739        msc_win_set_lockout(win, WIN_LOCKED, WIN_READY);
1740        if (msc->switch_on_unlock == win) {
1741                msc->switch_on_unlock = NULL;
1742                msc_win_switch(msc);
1743        }
1744}
1745EXPORT_SYMBOL_GPL(intel_th_msc_window_unlock);
1746
1747static void msc_work(struct work_struct *work)
1748{
1749        struct msc *msc = container_of(work, struct msc, work);
1750
1751        intel_th_msc_deactivate(msc->thdev);
1752}
1753
1754static irqreturn_t intel_th_msc_interrupt(struct intel_th_device *thdev)
1755{
1756        struct msc *msc = dev_get_drvdata(&thdev->dev);
1757        u32 msusts = ioread32(msc->msu_base + REG_MSU_MSUSTS);
1758        u32 mask = msc->index ? MSUSTS_MSC1BLAST : MSUSTS_MSC0BLAST;
1759        struct msc_window *win, *next_win;
1760
1761        if (!msc->do_irq || !msc->mbuf)
1762                return IRQ_NONE;
1763
1764        msusts &= mask;
1765
1766        if (!msusts)
1767                return msc->enabled ? IRQ_HANDLED : IRQ_NONE;
1768
1769        iowrite32(msusts, msc->msu_base + REG_MSU_MSUSTS);
1770
1771        if (!msc->enabled)
1772                return IRQ_NONE;
1773
1774        /* grab the window before we do the switch */
1775        win = msc->cur_win;
1776        if (!win)
1777                return IRQ_HANDLED;
1778        next_win = msc_next_window(win);
1779        if (!next_win)
1780                return IRQ_HANDLED;
1781
1782        /* next window: if READY, proceed, if LOCKED, stop the trace */
1783        if (msc_win_set_lockout(next_win, WIN_READY, WIN_INUSE)) {
1784                if (msc->stop_on_full)
1785                        schedule_work(&msc->work);
1786                else
1787                        msc->switch_on_unlock = next_win;
1788
1789                return IRQ_HANDLED;
1790        }
1791
1792        /* current window: INUSE -> LOCKED */
1793        msc_win_set_lockout(win, WIN_INUSE, WIN_LOCKED);
1794
1795        msc_win_switch(msc);
1796
1797        if (msc->mbuf && msc->mbuf->ready)
1798                msc->mbuf->ready(msc->mbuf_priv, win->sgt,
1799                                 msc_win_total_sz(win));
1800
1801        return IRQ_HANDLED;
1802}
1803
1804static const char * const msc_mode[] = {
1805        [MSC_MODE_SINGLE]       = "single",
1806        [MSC_MODE_MULTI]        = "multi",
1807        [MSC_MODE_EXI]          = "ExI",
1808        [MSC_MODE_DEBUG]        = "debug",
1809};
1810
1811static ssize_t
1812wrap_show(struct device *dev, struct device_attribute *attr, char *buf)
1813{
1814        struct msc *msc = dev_get_drvdata(dev);
1815
1816        return scnprintf(buf, PAGE_SIZE, "%d\n", msc->wrap);
1817}
1818
1819static ssize_t
1820wrap_store(struct device *dev, struct device_attribute *attr, const char *buf,
1821           size_t size)
1822{
1823        struct msc *msc = dev_get_drvdata(dev);
1824        unsigned long val;
1825        int ret;
1826
1827        ret = kstrtoul(buf, 10, &val);
1828        if (ret)
1829                return ret;
1830
1831        msc->wrap = !!val;
1832
1833        return size;
1834}
1835
1836static DEVICE_ATTR_RW(wrap);
1837
1838static void msc_buffer_unassign(struct msc *msc)
1839{
1840        lockdep_assert_held(&msc->buf_mutex);
1841
1842        if (!msc->mbuf)
1843                return;
1844
1845        msc->mbuf->unassign(msc->mbuf_priv);
1846        msu_buffer_put(msc->mbuf);
1847        msc->mbuf_priv = NULL;
1848        msc->mbuf = NULL;
1849}
1850
1851static ssize_t
1852mode_show(struct device *dev, struct device_attribute *attr, char *buf)
1853{
1854        struct msc *msc = dev_get_drvdata(dev);
1855        const char *mode = msc_mode[msc->mode];
1856        ssize_t ret;
1857
1858        mutex_lock(&msc->buf_mutex);
1859        if (msc->mbuf)
1860                mode = msc->mbuf->name;
1861        ret = scnprintf(buf, PAGE_SIZE, "%s\n", mode);
1862        mutex_unlock(&msc->buf_mutex);
1863
1864        return ret;
1865}
1866
1867static ssize_t
1868mode_store(struct device *dev, struct device_attribute *attr, const char *buf,
1869           size_t size)
1870{
1871        const struct msu_buffer *mbuf = NULL;
1872        struct msc *msc = dev_get_drvdata(dev);
1873        size_t len = size;
1874        char *cp, *mode;
1875        int i, ret;
1876
1877        if (!capable(CAP_SYS_RAWIO))
1878                return -EPERM;
1879
1880        cp = memchr(buf, '\n', len);
1881        if (cp)
1882                len = cp - buf;
1883
1884        mode = kstrndup(buf, len, GFP_KERNEL);
1885        if (!mode)
1886                return -ENOMEM;
1887
1888        i = match_string(msc_mode, ARRAY_SIZE(msc_mode), mode);
1889        if (i >= 0) {
1890                kfree(mode);
1891                goto found;
1892        }
1893
1894        /* Buffer sinks only work with a usable IRQ */
1895        if (!msc->do_irq) {
1896                kfree(mode);
1897                return -EINVAL;
1898        }
1899
1900        mbuf = msu_buffer_get(mode);
1901        kfree(mode);
1902        if (mbuf)
1903                goto found;
1904
1905        return -EINVAL;
1906
1907found:
1908        if (i == MSC_MODE_MULTI && msc->multi_is_broken)
1909                return -EOPNOTSUPP;
1910
1911        mutex_lock(&msc->buf_mutex);
1912        ret = 0;
1913
1914        /* Same buffer: do nothing */
1915        if (mbuf && mbuf == msc->mbuf) {
1916                /* put the extra reference we just got */
1917                msu_buffer_put(mbuf);
1918                goto unlock;
1919        }
1920
1921        ret = msc_buffer_unlocked_free_unless_used(msc);
1922        if (ret)
1923                goto unlock;
1924
1925        if (mbuf) {
1926                void *mbuf_priv = mbuf->assign(dev, &i);
1927
1928                if (!mbuf_priv) {
1929                        ret = -ENOMEM;
1930                        goto unlock;
1931                }
1932
1933                msc_buffer_unassign(msc);
1934                msc->mbuf_priv = mbuf_priv;
1935                msc->mbuf = mbuf;
1936        } else {
1937                msc_buffer_unassign(msc);
1938        }
1939
1940        msc->mode = i;
1941
1942unlock:
1943        if (ret && mbuf)
1944                msu_buffer_put(mbuf);
1945        mutex_unlock(&msc->buf_mutex);
1946
1947        return ret ? ret : size;
1948}
1949
1950static DEVICE_ATTR_RW(mode);
1951
1952static ssize_t
1953nr_pages_show(struct device *dev, struct device_attribute *attr, char *buf)
1954{
1955        struct msc *msc = dev_get_drvdata(dev);
1956        struct msc_window *win;
1957        size_t count = 0;
1958
1959        mutex_lock(&msc->buf_mutex);
1960
1961        if (msc->mode == MSC_MODE_SINGLE)
1962                count = scnprintf(buf, PAGE_SIZE, "%ld\n", msc->nr_pages);
1963        else if (msc->mode == MSC_MODE_MULTI) {
1964                list_for_each_entry(win, &msc->win_list, entry) {
1965                        count += scnprintf(buf + count, PAGE_SIZE - count,
1966                                           "%d%c", win->nr_blocks,
1967                                           msc_is_last_win(win) ? '\n' : ',');
1968                }
1969        } else {
1970                count = scnprintf(buf, PAGE_SIZE, "unsupported\n");
1971        }
1972
1973        mutex_unlock(&msc->buf_mutex);
1974
1975        return count;
1976}
1977
1978static ssize_t
1979nr_pages_store(struct device *dev, struct device_attribute *attr,
1980               const char *buf, size_t size)
1981{
1982        struct msc *msc = dev_get_drvdata(dev);
1983        unsigned long val, *win = NULL, *rewin;
1984        size_t len = size;
1985        const char *p = buf;
1986        char *end, *s;
1987        int ret, nr_wins = 0;
1988
1989        if (!capable(CAP_SYS_RAWIO))
1990                return -EPERM;
1991
1992        ret = msc_buffer_free_unless_used(msc);
1993        if (ret)
1994                return ret;
1995
1996        /* scan the comma-separated list of allocation sizes */
1997        end = memchr(buf, '\n', len);
1998        if (end)
1999                len = end - buf;
2000
2001        do {
2002                end = memchr(p, ',', len);
2003                s = kstrndup(p, end ? end - p : len, GFP_KERNEL);
2004                if (!s) {
2005                        ret = -ENOMEM;
2006                        goto free_win;
2007                }
2008
2009                ret = kstrtoul(s, 10, &val);
2010                kfree(s);
2011
2012                if (ret || !val)
2013                        goto free_win;
2014
2015                if (nr_wins && msc->mode == MSC_MODE_SINGLE) {
2016                        ret = -EINVAL;
2017                        goto free_win;
2018                }
2019
2020                nr_wins++;
2021                rewin = krealloc_array(win, nr_wins, sizeof(*win), GFP_KERNEL);
2022                if (!rewin) {
2023                        kfree(win);
2024                        return -ENOMEM;
2025                }
2026
2027                win = rewin;
2028                win[nr_wins - 1] = val;
2029
2030                if (!end)
2031                        break;
2032
2033                /* consume the number and the following comma, hence +1 */
2034                len -= end - p + 1;
2035                p = end + 1;
2036        } while (len);
2037
2038        mutex_lock(&msc->buf_mutex);
2039        ret = msc_buffer_alloc(msc, win, nr_wins);
2040        mutex_unlock(&msc->buf_mutex);
2041
2042free_win:
2043        kfree(win);
2044
2045        return ret ? ret : size;
2046}
2047
2048static DEVICE_ATTR_RW(nr_pages);
2049
2050static ssize_t
2051win_switch_store(struct device *dev, struct device_attribute *attr,
2052                 const char *buf, size_t size)
2053{
2054        struct msc *msc = dev_get_drvdata(dev);
2055        unsigned long val;
2056        int ret;
2057
2058        ret = kstrtoul(buf, 10, &val);
2059        if (ret)
2060                return ret;
2061
2062        if (val != 1)
2063                return -EINVAL;
2064
2065        ret = -EINVAL;
2066        mutex_lock(&msc->buf_mutex);
2067        /*
2068         * Window switch can only happen in the "multi" mode.
2069         * If a external buffer is engaged, they have the full
2070         * control over window switching.
2071         */
2072        if (msc->mode == MSC_MODE_MULTI && !msc->mbuf)
2073                ret = msc_win_switch(msc);
2074        mutex_unlock(&msc->buf_mutex);
2075
2076        return ret ? ret : size;
2077}
2078
2079static DEVICE_ATTR_WO(win_switch);
2080
2081static ssize_t stop_on_full_show(struct device *dev,
2082                                 struct device_attribute *attr, char *buf)
2083{
2084        struct msc *msc = dev_get_drvdata(dev);
2085
2086        return sprintf(buf, "%d\n", msc->stop_on_full);
2087}
2088
2089static ssize_t stop_on_full_store(struct device *dev,
2090                                  struct device_attribute *attr,
2091                                  const char *buf, size_t size)
2092{
2093        struct msc *msc = dev_get_drvdata(dev);
2094        int ret;
2095
2096        ret = kstrtobool(buf, &msc->stop_on_full);
2097        if (ret)
2098                return ret;
2099
2100        return size;
2101}
2102
2103static DEVICE_ATTR_RW(stop_on_full);
2104
2105static struct attribute *msc_output_attrs[] = {
2106        &dev_attr_wrap.attr,
2107        &dev_attr_mode.attr,
2108        &dev_attr_nr_pages.attr,
2109        &dev_attr_win_switch.attr,
2110        &dev_attr_stop_on_full.attr,
2111        NULL,
2112};
2113
2114static const struct attribute_group msc_output_group = {
2115        .attrs  = msc_output_attrs,
2116};
2117
2118static int intel_th_msc_probe(struct intel_th_device *thdev)
2119{
2120        struct device *dev = &thdev->dev;
2121        struct resource *res;
2122        struct msc *msc;
2123        void __iomem *base;
2124        int err;
2125
2126        res = intel_th_device_get_resource(thdev, IORESOURCE_MEM, 0);
2127        if (!res)
2128                return -ENODEV;
2129
2130        base = devm_ioremap(dev, res->start, resource_size(res));
2131        if (!base)
2132                return -ENOMEM;
2133
2134        msc = devm_kzalloc(dev, sizeof(*msc), GFP_KERNEL);
2135        if (!msc)
2136                return -ENOMEM;
2137
2138        res = intel_th_device_get_resource(thdev, IORESOURCE_IRQ, 1);
2139        if (!res)
2140                msc->do_irq = 1;
2141
2142        if (INTEL_TH_CAP(to_intel_th(thdev), multi_is_broken))
2143                msc->multi_is_broken = 1;
2144
2145        msc->index = thdev->id;
2146
2147        msc->thdev = thdev;
2148        msc->reg_base = base + msc->index * 0x100;
2149        msc->msu_base = base;
2150
2151        INIT_WORK(&msc->work, msc_work);
2152        err = intel_th_msc_init(msc);
2153        if (err)
2154                return err;
2155
2156        dev_set_drvdata(dev, msc);
2157
2158        return 0;
2159}
2160
2161static void intel_th_msc_remove(struct intel_th_device *thdev)
2162{
2163        struct msc *msc = dev_get_drvdata(&thdev->dev);
2164        int ret;
2165
2166        intel_th_msc_deactivate(thdev);
2167
2168        /*
2169         * Buffers should not be used at this point except if the
2170         * output character device is still open and the parent
2171         * device gets detached from its bus, which is a FIXME.
2172         */
2173        ret = msc_buffer_free_unless_used(msc);
2174        WARN_ON_ONCE(ret);
2175}
2176
2177static struct intel_th_driver intel_th_msc_driver = {
2178        .probe  = intel_th_msc_probe,
2179        .remove = intel_th_msc_remove,
2180        .irq            = intel_th_msc_interrupt,
2181        .wait_empty     = intel_th_msc_wait_empty,
2182        .activate       = intel_th_msc_activate,
2183        .deactivate     = intel_th_msc_deactivate,
2184        .fops   = &intel_th_msc_fops,
2185        .attr_group     = &msc_output_group,
2186        .driver = {
2187                .name   = "msc",
2188                .owner  = THIS_MODULE,
2189        },
2190};
2191
2192module_driver(intel_th_msc_driver,
2193              intel_th_driver_register,
2194              intel_th_driver_unregister);
2195
2196MODULE_LICENSE("GPL v2");
2197MODULE_DESCRIPTION("Intel(R) Trace Hub Memory Storage Unit driver");
2198MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@linux.intel.com>");
2199
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