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 * @msc:	pointer to the MSC device
  65 * @_sgt:	array of block descriptors
  66 * @sgt:	array of block descriptors
  67 */
  68struct msc_window {
  69	struct list_head	entry;
  70	unsigned long		pgoff;
  71	enum lockout_state	lockout;
  72	spinlock_t		lo_lock;
  73	unsigned int		nr_blocks;
  74	unsigned int		nr_segs;
  75	struct msc		*msc;
  76	struct sg_table		_sgt;
  77	struct sg_table		*sgt;
  78};
  79
  80/**
  81 * struct msc_iter - iterator for msc buffer
  82 * @entry:		msc::iter_list linkage
  83 * @msc:		pointer to the MSC device
  84 * @start_win:		oldest window
  85 * @win:		current window
  86 * @offset:		current logical offset into the buffer
  87 * @start_block:	oldest block in the window
  88 * @block:		block number in the window
  89 * @block_off:		offset into current block
  90 * @wrap_count:		block wrapping handling
  91 * @eof:		end of buffer reached
  92 */
  93struct msc_iter {
  94	struct list_head	entry;
  95	struct msc		*msc;
  96	struct msc_window	*start_win;
  97	struct msc_window	*win;
  98	unsigned long		offset;
  99	struct scatterlist	*start_block;
 100	struct scatterlist	*block;
 101	unsigned int		block_off;
 102	unsigned int		wrap_count;
 103	unsigned int		eof;
 104};
 105
 106/**
 107 * struct msc - MSC device representation
 108 * @reg_base:		register window base address
 109 * @thdev:		intel_th_device pointer
 110 * @mbuf:		MSU buffer, if assigned
 111 * @mbuf_priv		MSU buffer's private data, if @mbuf
 112 * @win_list:		list of windows in multiblock mode
 113 * @single_sgt:		single mode buffer
 114 * @cur_win:		current window
 115 * @nr_pages:		total number of pages allocated for this buffer
 116 * @single_sz:		amount of data in single mode
 117 * @single_wrap:	single mode wrap occurred
 118 * @base:		buffer's base pointer
 119 * @base_addr:		buffer's base address
 120 * @user_count:		number of users of the buffer
 121 * @mmap_count:		number of mappings
 122 * @buf_mutex:		mutex to serialize access to buffer-related bits
 
 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
 662		for_each_sg(win->sgt->sgl, sg, win->nr_segs, blk) {
 663			struct msc_block_desc *bdesc = sg_virt(sg);
 664
 665			memset_startat(bdesc, 0, hw_tag);
 666		}
 667	}
 668}
 669
 670static int intel_th_msu_init(struct msc *msc)
 671{
 672	u32 mintctl, msusts;
 673
 674	if (!msc->do_irq)
 675		return 0;
 676
 677	if (!msc->mbuf)
 678		return 0;
 679
 680	mintctl = ioread32(msc->msu_base + REG_MSU_MINTCTL);
 681	mintctl |= msc->index ? M1BLIE : M0BLIE;
 682	iowrite32(mintctl, msc->msu_base + REG_MSU_MINTCTL);
 683	if (mintctl != ioread32(msc->msu_base + REG_MSU_MINTCTL)) {
 684		dev_info(msc_dev(msc), "MINTCTL ignores writes: no usable interrupts\n");
 685		msc->do_irq = 0;
 686		return 0;
 687	}
 688
 689	msusts = ioread32(msc->msu_base + REG_MSU_MSUSTS);
 690	iowrite32(msusts, msc->msu_base + REG_MSU_MSUSTS);
 691
 692	return 0;
 693}
 694
 695static void intel_th_msu_deinit(struct msc *msc)
 696{
 697	u32 mintctl;
 698
 699	if (!msc->do_irq)
 700		return;
 701
 702	mintctl = ioread32(msc->msu_base + REG_MSU_MINTCTL);
 703	mintctl &= msc->index ? ~M1BLIE : ~M0BLIE;
 704	iowrite32(mintctl, msc->msu_base + REG_MSU_MINTCTL);
 705}
 706
 707static int msc_win_set_lockout(struct msc_window *win,
 708			       enum lockout_state expect,
 709			       enum lockout_state new)
 710{
 711	enum lockout_state old;
 712	unsigned long flags;
 713	int ret = 0;
 714
 715	if (!win->msc->mbuf)
 716		return 0;
 717
 718	spin_lock_irqsave(&win->lo_lock, flags);
 719	old = win->lockout;
 720
 721	if (old != expect) {
 722		ret = -EINVAL;
 
 
 
 723		goto unlock;
 724	}
 725
 726	win->lockout = new;
 727
 728	if (old == expect && new == WIN_LOCKED)
 729		atomic_inc(&win->msc->user_count);
 730	else if (old == expect && old == WIN_LOCKED)
 731		atomic_dec(&win->msc->user_count);
 732
 733unlock:
 734	spin_unlock_irqrestore(&win->lo_lock, flags);
 735
 736	if (ret) {
 737		if (expect == WIN_READY && old == WIN_LOCKED)
 738			return -EBUSY;
 739
 740		/* from intel_th_msc_window_unlock(), don't warn if not locked */
 741		if (expect == WIN_LOCKED && old == new)
 742			return 0;
 743
 744		dev_warn_ratelimited(msc_dev(win->msc),
 745				     "expected lockout state %d, got %d\n",
 746				     expect, old);
 747	}
 748
 749	return ret;
 750}
 751/**
 752 * msc_configure() - set up MSC hardware
 753 * @msc:	the MSC device to configure
 754 *
 755 * Program storage mode, wrapping, burst length and trace buffer address
 756 * into a given MSC. Then, enable tracing and set msc::enabled.
 757 * The latter is serialized on msc::buf_mutex, so make sure to hold it.
 758 *
 759 * Return:	%0 for success or a negative error code otherwise.
 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
1072static struct page *msc_sg_page(struct scatterlist *sg)
1073{
1074	void *addr = sg_virt(sg);
1075
1076	if (is_vmalloc_addr(addr))
1077		return vmalloc_to_page(addr);
1078
1079	return sg_page(sg);
1080}
1081
1082/**
1083 * msc_buffer_win_alloc() - alloc a window for a multiblock mode
1084 * @msc:	MSC device
1085 * @nr_blocks:	number of pages in this window
1086 *
1087 * This modifies msc::win_list and msc::base, which requires msc::buf_mutex
1088 * to serialize, so the caller is expected to hold it.
1089 *
1090 * Return:	0 on success, -errno otherwise.
1091 */
1092static int msc_buffer_win_alloc(struct msc *msc, unsigned int nr_blocks)
1093{
1094	struct msc_window *win;
1095	int ret = -ENOMEM;
1096
1097	if (!nr_blocks)
1098		return 0;
1099
1100	win = kzalloc(sizeof(*win), GFP_KERNEL);
1101	if (!win)
1102		return -ENOMEM;
1103
1104	win->msc = msc;
1105	win->sgt = &win->_sgt;
1106	win->lockout = WIN_READY;
1107	spin_lock_init(&win->lo_lock);
1108
1109	if (!list_empty(&msc->win_list)) {
1110		struct msc_window *prev = list_last_entry(&msc->win_list,
1111							  struct msc_window,
1112							  entry);
1113
1114		win->pgoff = prev->pgoff + prev->nr_blocks;
1115	}
1116
1117	if (msc->mbuf && msc->mbuf->alloc_window)
1118		ret = msc->mbuf->alloc_window(msc->mbuf_priv, &win->sgt,
1119					      nr_blocks << PAGE_SHIFT);
1120	else
1121		ret = __msc_buffer_win_alloc(win, nr_blocks);
1122
1123	if (ret <= 0)
1124		goto err_nomem;
1125
 
 
1126	win->nr_segs = ret;
1127	win->nr_blocks = nr_blocks;
1128
1129	if (list_empty(&msc->win_list)) {
1130		msc->base = msc_win_base(win);
1131		msc->base_addr = msc_win_base_dma(win);
1132		msc->cur_win = win;
1133	}
1134
1135	list_add_tail(&win->entry, &msc->win_list);
1136	msc->nr_pages += nr_blocks;
1137
1138	return 0;
1139
1140err_nomem:
1141	kfree(win);
1142
1143	return ret;
1144}
1145
1146static void __msc_buffer_win_free(struct msc *msc, struct msc_window *win)
1147{
1148	struct scatterlist *sg;
1149	int i;
1150
1151	for_each_sg(win->sgt->sgl, sg, win->nr_segs, i) {
1152		struct page *page = msc_sg_page(sg);
1153
1154		page->mapping = NULL;
1155		dma_free_coherent(msc_dev(win->msc)->parent->parent, PAGE_SIZE,
1156				  sg_virt(sg), sg_dma_address(sg));
1157	}
1158	sg_free_table(win->sgt);
1159}
1160
1161/**
1162 * msc_buffer_win_free() - free a window from MSC's window list
1163 * @msc:	MSC device
1164 * @win:	window to free
1165 *
1166 * This modifies msc::win_list and msc::base, which requires msc::buf_mutex
1167 * to serialize, so the caller is expected to hold it.
1168 */
1169static void msc_buffer_win_free(struct msc *msc, struct msc_window *win)
1170{
1171	msc->nr_pages -= win->nr_blocks;
1172
1173	list_del(&win->entry);
1174	if (list_empty(&msc->win_list)) {
1175		msc->base = NULL;
1176		msc->base_addr = 0;
1177	}
1178
 
 
1179	if (msc->mbuf && msc->mbuf->free_window)
1180		msc->mbuf->free_window(msc->mbuf_priv, win->sgt);
1181	else
1182		__msc_buffer_win_free(msc, win);
1183
1184	kfree(win);
1185}
1186
1187/**
1188 * msc_buffer_relink() - set up block descriptors for multiblock mode
1189 * @msc:	MSC device
1190 *
1191 * This traverses msc::win_list, which requires msc::buf_mutex to serialize,
1192 * so the caller is expected to hold it.
1193 */
1194static void msc_buffer_relink(struct msc *msc)
1195{
1196	struct msc_window *win, *next_win;
1197
1198	/* call with msc::mutex locked */
1199	list_for_each_entry(win, &msc->win_list, entry) {
1200		struct scatterlist *sg;
1201		unsigned int blk;
1202		u32 sw_tag = 0;
1203
1204		/*
1205		 * Last window's next_win should point to the first window
1206		 * and MSC_SW_TAG_LASTWIN should be set.
1207		 */
1208		if (msc_is_last_win(win)) {
1209			sw_tag |= MSC_SW_TAG_LASTWIN;
1210			next_win = list_first_entry(&msc->win_list,
1211						    struct msc_window, entry);
1212		} else {
1213			next_win = list_next_entry(win, entry);
1214		}
1215
1216		for_each_sg(win->sgt->sgl, sg, win->nr_segs, blk) {
1217			struct msc_block_desc *bdesc = sg_virt(sg);
1218
1219			memset(bdesc, 0, sizeof(*bdesc));
1220
1221			bdesc->next_win = msc_win_base_pfn(next_win);
1222
1223			/*
1224			 * Similarly to last window, last block should point
1225			 * to the first one.
1226			 */
1227			if (blk == win->nr_segs - 1) {
1228				sw_tag |= MSC_SW_TAG_LASTBLK;
1229				bdesc->next_blk = msc_win_base_pfn(win);
1230			} else {
1231				dma_addr_t addr = sg_dma_address(sg_next(sg));
1232
1233				bdesc->next_blk = PFN_DOWN(addr);
1234			}
1235
1236			bdesc->sw_tag = sw_tag;
1237			bdesc->block_sz = sg->length / 64;
1238		}
1239	}
1240
1241	/*
1242	 * Make the above writes globally visible before tracing is
1243	 * enabled to make sure hardware sees them coherently.
1244	 */
1245	wmb();
1246}
1247
1248static void msc_buffer_multi_free(struct msc *msc)
1249{
1250	struct msc_window *win, *iter;
1251
1252	list_for_each_entry_safe(win, iter, &msc->win_list, entry)
1253		msc_buffer_win_free(msc, win);
1254}
1255
1256static int msc_buffer_multi_alloc(struct msc *msc, unsigned long *nr_pages,
1257				  unsigned int nr_wins)
1258{
1259	int ret, i;
1260
1261	for (i = 0; i < nr_wins; i++) {
1262		ret = msc_buffer_win_alloc(msc, nr_pages[i]);
1263		if (ret) {
1264			msc_buffer_multi_free(msc);
1265			return ret;
1266		}
1267	}
1268
1269	msc_buffer_relink(msc);
1270
1271	return 0;
1272}
1273
1274/**
1275 * msc_buffer_free() - free buffers for MSC
1276 * @msc:	MSC device
1277 *
1278 * Free MSC's storage buffers.
1279 *
1280 * This modifies msc::win_list and msc::base, which requires msc::buf_mutex to
1281 * serialize, so the caller is expected to hold it.
1282 */
1283static void msc_buffer_free(struct msc *msc)
1284{
1285	msc_buffer_set_wb(msc);
1286
1287	if (msc->mode == MSC_MODE_SINGLE)
1288		msc_buffer_contig_free(msc);
1289	else if (msc->mode == MSC_MODE_MULTI)
1290		msc_buffer_multi_free(msc);
1291}
1292
1293/**
1294 * msc_buffer_alloc() - allocate a buffer for MSC
1295 * @msc:	MSC device
1296 * @nr_pages:	number of pages for each window
1297 * @nr_wins:	number of windows
1298 *
1299 * Allocate a storage buffer for MSC, depending on the msc::mode, it will be
1300 * either done via msc_buffer_contig_alloc() for SINGLE operation mode or
1301 * msc_buffer_win_alloc() for multiblock operation. The latter allocates one
1302 * window per invocation, so in multiblock mode this can be called multiple
1303 * times for the same MSC to allocate multiple windows.
1304 *
1305 * This modifies msc::win_list and msc::base, which requires msc::buf_mutex
1306 * to serialize, so the caller is expected to hold it.
1307 *
1308 * Return:	0 on success, -errno otherwise.
1309 */
1310static int msc_buffer_alloc(struct msc *msc, unsigned long *nr_pages,
1311			    unsigned int nr_wins)
1312{
1313	int ret;
1314
1315	/* -1: buffer not allocated */
1316	if (atomic_read(&msc->user_count) != -1)
1317		return -EBUSY;
1318
1319	if (msc->mode == MSC_MODE_SINGLE) {
1320		if (nr_wins != 1)
1321			return -EINVAL;
1322
1323		ret = msc_buffer_contig_alloc(msc, nr_pages[0] << PAGE_SHIFT);
1324	} else if (msc->mode == MSC_MODE_MULTI) {
1325		ret = msc_buffer_multi_alloc(msc, nr_pages, nr_wins);
1326	} else {
1327		ret = -EINVAL;
1328	}
1329
1330	if (!ret) {
1331		msc_buffer_set_uc(msc);
1332
1333		/* allocation should be visible before the counter goes to 0 */
1334		smp_mb__before_atomic();
1335
1336		if (WARN_ON_ONCE(atomic_cmpxchg(&msc->user_count, -1, 0) != -1))
1337			return -EINVAL;
1338	}
1339
1340	return ret;
1341}
1342
1343/**
1344 * msc_buffer_unlocked_free_unless_used() - free a buffer unless it's in use
1345 * @msc:	MSC device
1346 *
1347 * This will free MSC buffer unless it is in use or there is no allocated
1348 * buffer.
1349 * Caller needs to hold msc::buf_mutex.
1350 *
1351 * Return:	0 on successful deallocation or if there was no buffer to
1352 *		deallocate, -EBUSY if there are active users.
1353 */
1354static int msc_buffer_unlocked_free_unless_used(struct msc *msc)
1355{
1356	int count, ret = 0;
1357
1358	count = atomic_cmpxchg(&msc->user_count, 0, -1);
1359
1360	/* > 0: buffer is allocated and has users */
1361	if (count > 0)
1362		ret = -EBUSY;
1363	/* 0: buffer is allocated, no users */
1364	else if (!count)
1365		msc_buffer_free(msc);
1366	/* < 0: no buffer, nothing to do */
1367
1368	return ret;
1369}
1370
1371/**
1372 * msc_buffer_free_unless_used() - free a buffer unless it's in use
1373 * @msc:	MSC device
1374 *
1375 * This is a locked version of msc_buffer_unlocked_free_unless_used().
1376 *
1377 * Return:	0 on successful deallocation or if there was no buffer to
1378 *		deallocate, -EBUSY if there are active users.
1379 */
1380static int msc_buffer_free_unless_used(struct msc *msc)
1381{
1382	int ret;
1383
1384	mutex_lock(&msc->buf_mutex);
1385	ret = msc_buffer_unlocked_free_unless_used(msc);
1386	mutex_unlock(&msc->buf_mutex);
1387
1388	return ret;
1389}
1390
1391/**
1392 * msc_buffer_get_page() - get MSC buffer page at a given offset
1393 * @msc:	MSC device
1394 * @pgoff:	page offset into the storage buffer
1395 *
1396 * This traverses msc::win_list, so holding msc::buf_mutex is expected from
1397 * the caller.
1398 *
1399 * Return:	page if @pgoff corresponds to a valid buffer page or NULL.
1400 */
1401static struct page *msc_buffer_get_page(struct msc *msc, unsigned long pgoff)
1402{
1403	struct msc_window *win;
1404	struct scatterlist *sg;
1405	unsigned int blk;
1406
1407	if (msc->mode == MSC_MODE_SINGLE)
1408		return msc_buffer_contig_get_page(msc, pgoff);
1409
1410	list_for_each_entry(win, &msc->win_list, entry)
1411		if (pgoff >= win->pgoff && pgoff < win->pgoff + win->nr_blocks)
1412			goto found;
1413
1414	return NULL;
1415
1416found:
1417	pgoff -= win->pgoff;
1418
1419	for_each_sg(win->sgt->sgl, sg, win->nr_segs, blk) {
1420		struct page *page = msc_sg_page(sg);
1421		size_t pgsz = PFN_DOWN(sg->length);
1422
1423		if (pgoff < pgsz)
1424			return page + pgoff;
1425
1426		pgoff -= pgsz;
1427	}
1428
1429	return NULL;
1430}
1431
1432/**
1433 * struct msc_win_to_user_struct - data for copy_to_user() callback
1434 * @buf:	userspace buffer to copy data to
1435 * @offset:	running offset
1436 */
1437struct msc_win_to_user_struct {
1438	char __user	*buf;
1439	unsigned long	offset;
1440};
1441
1442/**
1443 * msc_win_to_user() - iterator for msc_buffer_iterate() to copy data to user
1444 * @data:	callback's private data
1445 * @src:	source buffer
1446 * @len:	amount of data to copy from the source buffer
1447 *
1448 * Return:	>= %0 for success or -errno for error.
1449 */
1450static unsigned long msc_win_to_user(void *data, void *src, size_t len)
1451{
1452	struct msc_win_to_user_struct *u = data;
1453	unsigned long ret;
1454
1455	ret = copy_to_user(u->buf + u->offset, src, len);
1456	u->offset += len - ret;
1457
1458	return ret;
1459}
1460
1461
1462/*
1463 * file operations' callbacks
1464 */
1465
1466static int intel_th_msc_open(struct inode *inode, struct file *file)
1467{
1468	struct intel_th_device *thdev = file->private_data;
1469	struct msc *msc = dev_get_drvdata(&thdev->dev);
1470	struct msc_iter *iter;
1471
1472	if (!capable(CAP_SYS_RAWIO))
1473		return -EPERM;
1474
1475	iter = msc_iter_install(msc);
1476	if (IS_ERR(iter))
1477		return PTR_ERR(iter);
1478
1479	file->private_data = iter;
1480
1481	return nonseekable_open(inode, file);
1482}
1483
1484static int intel_th_msc_release(struct inode *inode, struct file *file)
1485{
1486	struct msc_iter *iter = file->private_data;
1487	struct msc *msc = iter->msc;
1488
1489	msc_iter_remove(iter, msc);
1490
1491	return 0;
1492}
1493
1494static ssize_t
1495msc_single_to_user(struct msc *msc, char __user *buf, loff_t off, size_t len)
1496{
1497	unsigned long size = msc->nr_pages << PAGE_SHIFT, rem = len;
1498	unsigned long start = off, tocopy = 0;
1499
1500	if (msc->single_wrap) {
1501		start += msc->single_sz;
1502		if (start < size) {
1503			tocopy = min(rem, size - start);
1504			if (copy_to_user(buf, msc->base + start, tocopy))
1505				return -EFAULT;
1506
1507			buf += tocopy;
1508			rem -= tocopy;
1509			start += tocopy;
1510		}
1511
1512		start &= size - 1;
1513		if (rem) {
1514			tocopy = min(rem, msc->single_sz - start);
1515			if (copy_to_user(buf, msc->base + start, tocopy))
1516				return -EFAULT;
1517
1518			rem -= tocopy;
1519		}
1520
1521		return len - rem;
1522	}
1523
1524	if (copy_to_user(buf, msc->base + start, rem))
1525		return -EFAULT;
1526
1527	return len;
1528}
1529
1530static ssize_t intel_th_msc_read(struct file *file, char __user *buf,
1531				 size_t len, loff_t *ppos)
1532{
1533	struct msc_iter *iter = file->private_data;
1534	struct msc *msc = iter->msc;
1535	size_t size;
1536	loff_t off = *ppos;
1537	ssize_t ret = 0;
1538
1539	if (!atomic_inc_unless_negative(&msc->user_count))
1540		return 0;
1541
1542	if (msc->mode == MSC_MODE_SINGLE && !msc->single_wrap)
1543		size = msc->single_sz;
1544	else
1545		size = msc->nr_pages << PAGE_SHIFT;
1546
1547	if (!size)
1548		goto put_count;
1549
1550	if (off >= size)
1551		goto put_count;
1552
1553	if (off + len >= size)
1554		len = size - off;
1555
1556	if (msc->mode == MSC_MODE_SINGLE) {
1557		ret = msc_single_to_user(msc, buf, off, len);
1558		if (ret >= 0)
1559			*ppos += ret;
1560	} else if (msc->mode == MSC_MODE_MULTI) {
1561		struct msc_win_to_user_struct u = {
1562			.buf	= buf,
1563			.offset	= 0,
1564		};
1565
1566		ret = msc_buffer_iterate(iter, len, &u, msc_win_to_user);
1567		if (ret >= 0)
1568			*ppos = iter->offset;
1569	} else {
1570		ret = -EINVAL;
1571	}
1572
1573put_count:
1574	atomic_dec(&msc->user_count);
1575
1576	return ret;
1577}
1578
1579/*
1580 * vm operations callbacks (vm_ops)
1581 */
1582
1583static void msc_mmap_open(struct vm_area_struct *vma)
1584{
1585	struct msc_iter *iter = vma->vm_file->private_data;
1586	struct msc *msc = iter->msc;
1587
1588	atomic_inc(&msc->mmap_count);
1589}
1590
1591static void msc_mmap_close(struct vm_area_struct *vma)
1592{
1593	struct msc_iter *iter = vma->vm_file->private_data;
1594	struct msc *msc = iter->msc;
1595	unsigned long pg;
1596
1597	if (!atomic_dec_and_mutex_lock(&msc->mmap_count, &msc->buf_mutex))
1598		return;
1599
1600	/* drop page _refcounts */
1601	for (pg = 0; pg < msc->nr_pages; pg++) {
1602		struct page *page = msc_buffer_get_page(msc, pg);
1603
1604		if (WARN_ON_ONCE(!page))
1605			continue;
1606
1607		if (page->mapping)
1608			page->mapping = NULL;
1609	}
1610
1611	/* last mapping -- drop user_count */
1612	atomic_dec(&msc->user_count);
1613	mutex_unlock(&msc->buf_mutex);
1614}
1615
1616static vm_fault_t msc_mmap_fault(struct vm_fault *vmf)
1617{
1618	struct msc_iter *iter = vmf->vma->vm_file->private_data;
1619	struct msc *msc = iter->msc;
1620
1621	vmf->page = msc_buffer_get_page(msc, vmf->pgoff);
1622	if (!vmf->page)
1623		return VM_FAULT_SIGBUS;
1624
1625	get_page(vmf->page);
1626	vmf->page->mapping = vmf->vma->vm_file->f_mapping;
1627	vmf->page->index = vmf->pgoff;
1628
1629	return 0;
1630}
1631
1632static const struct vm_operations_struct msc_mmap_ops = {
1633	.open	= msc_mmap_open,
1634	.close	= msc_mmap_close,
1635	.fault	= msc_mmap_fault,
1636};
1637
1638static int intel_th_msc_mmap(struct file *file, struct vm_area_struct *vma)
1639{
1640	unsigned long size = vma->vm_end - vma->vm_start;
1641	struct msc_iter *iter = vma->vm_file->private_data;
1642	struct msc *msc = iter->msc;
1643	int ret = -EINVAL;
1644
1645	if (!size || offset_in_page(size))
1646		return -EINVAL;
1647
1648	if (vma->vm_pgoff)
1649		return -EINVAL;
1650
1651	/* grab user_count once per mmap; drop in msc_mmap_close() */
1652	if (!atomic_inc_unless_negative(&msc->user_count))
1653		return -EINVAL;
1654
1655	if (msc->mode != MSC_MODE_SINGLE &&
1656	    msc->mode != MSC_MODE_MULTI)
1657		goto out;
1658
1659	if (size >> PAGE_SHIFT != msc->nr_pages)
1660		goto out;
1661
1662	atomic_set(&msc->mmap_count, 1);
1663	ret = 0;
1664
1665out:
1666	if (ret)
1667		atomic_dec(&msc->user_count);
1668
1669	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
1670	vm_flags_set(vma, VM_DONTEXPAND | VM_DONTCOPY);
1671	vma->vm_ops = &msc_mmap_ops;
1672	return ret;
1673}
1674
1675static const struct file_operations intel_th_msc_fops = {
1676	.open		= intel_th_msc_open,
1677	.release	= intel_th_msc_release,
1678	.read		= intel_th_msc_read,
1679	.mmap		= intel_th_msc_mmap,
 
1680	.owner		= THIS_MODULE,
1681};
1682
1683static void intel_th_msc_wait_empty(struct intel_th_device *thdev)
1684{
1685	struct msc *msc = dev_get_drvdata(&thdev->dev);
1686	unsigned long count;
1687	u32 reg;
1688
1689	for (reg = 0, count = MSC_PLE_WAITLOOP_DEPTH;
1690	     count && !(reg & MSCSTS_PLE); count--) {
1691		reg = __raw_readl(msc->reg_base + REG_MSU_MSC0STS);
1692		cpu_relax();
1693	}
1694
1695	if (!count)
1696		dev_dbg(msc_dev(msc), "timeout waiting for MSC0 PLE\n");
1697}
1698
1699static int intel_th_msc_init(struct msc *msc)
1700{
1701	atomic_set(&msc->user_count, -1);
1702
1703	msc->mode = msc->multi_is_broken ? MSC_MODE_SINGLE : MSC_MODE_MULTI;
1704	mutex_init(&msc->buf_mutex);
1705	INIT_LIST_HEAD(&msc->win_list);
1706	INIT_LIST_HEAD(&msc->iter_list);
1707
1708	msc->burst_len =
1709		(ioread32(msc->reg_base + REG_MSU_MSC0CTL) & MSC_LEN) >>
1710		__ffs(MSC_LEN);
1711
1712	return 0;
1713}
1714
1715static int msc_win_switch(struct msc *msc)
1716{
1717	struct msc_window *first;
1718
1719	if (list_empty(&msc->win_list))
1720		return -EINVAL;
1721
1722	first = list_first_entry(&msc->win_list, struct msc_window, entry);
1723
1724	if (msc_is_last_win(msc->cur_win))
1725		msc->cur_win = first;
1726	else
1727		msc->cur_win = list_next_entry(msc->cur_win, entry);
1728
1729	msc->base = msc_win_base(msc->cur_win);
1730	msc->base_addr = msc_win_base_dma(msc->cur_win);
1731
1732	intel_th_trace_switch(msc->thdev);
1733
1734	return 0;
1735}
1736
1737/**
1738 * intel_th_msc_window_unlock - put the window back in rotation
1739 * @dev:	MSC device to which this relates
1740 * @sgt:	buffer's sg_table for the window, does nothing if NULL
1741 */
1742void intel_th_msc_window_unlock(struct device *dev, struct sg_table *sgt)
1743{
1744	struct msc *msc = dev_get_drvdata(dev);
1745	struct msc_window *win;
1746
1747	if (!sgt)
1748		return;
1749
1750	win = msc_find_window(msc, sgt, false);
1751	if (!win)
1752		return;
1753
1754	msc_win_set_lockout(win, WIN_LOCKED, WIN_READY);
1755	if (msc->switch_on_unlock == win) {
1756		msc->switch_on_unlock = NULL;
1757		msc_win_switch(msc);
1758	}
1759}
1760EXPORT_SYMBOL_GPL(intel_th_msc_window_unlock);
1761
1762static void msc_work(struct work_struct *work)
1763{
1764	struct msc *msc = container_of(work, struct msc, work);
1765
1766	intel_th_msc_deactivate(msc->thdev);
1767}
1768
1769static irqreturn_t intel_th_msc_interrupt(struct intel_th_device *thdev)
1770{
1771	struct msc *msc = dev_get_drvdata(&thdev->dev);
1772	u32 msusts = ioread32(msc->msu_base + REG_MSU_MSUSTS);
1773	u32 mask = msc->index ? MSUSTS_MSC1BLAST : MSUSTS_MSC0BLAST;
1774	struct msc_window *win, *next_win;
1775
1776	if (!msc->do_irq || !msc->mbuf)
1777		return IRQ_NONE;
1778
1779	msusts &= mask;
1780
1781	if (!msusts)
1782		return msc->enabled ? IRQ_HANDLED : IRQ_NONE;
1783
1784	iowrite32(msusts, msc->msu_base + REG_MSU_MSUSTS);
1785
1786	if (!msc->enabled)
1787		return IRQ_NONE;
1788
1789	/* grab the window before we do the switch */
1790	win = msc->cur_win;
1791	if (!win)
1792		return IRQ_HANDLED;
1793	next_win = msc_next_window(win);
1794	if (!next_win)
1795		return IRQ_HANDLED;
1796
1797	/* next window: if READY, proceed, if LOCKED, stop the trace */
1798	if (msc_win_set_lockout(next_win, WIN_READY, WIN_INUSE)) {
1799		if (msc->stop_on_full)
1800			schedule_work(&msc->work);
1801		else
1802			msc->switch_on_unlock = next_win;
1803
1804		return IRQ_HANDLED;
1805	}
1806
1807	/* current window: INUSE -> LOCKED */
1808	msc_win_set_lockout(win, WIN_INUSE, WIN_LOCKED);
1809
1810	msc_win_switch(msc);
1811
1812	if (msc->mbuf && msc->mbuf->ready)
1813		msc->mbuf->ready(msc->mbuf_priv, win->sgt,
1814				 msc_win_total_sz(win));
1815
1816	return IRQ_HANDLED;
1817}
1818
1819static const char * const msc_mode[] = {
1820	[MSC_MODE_SINGLE]	= "single",
1821	[MSC_MODE_MULTI]	= "multi",
1822	[MSC_MODE_EXI]		= "ExI",
1823	[MSC_MODE_DEBUG]	= "debug",
1824};
1825
1826static ssize_t
1827wrap_show(struct device *dev, struct device_attribute *attr, char *buf)
1828{
1829	struct msc *msc = dev_get_drvdata(dev);
1830
1831	return scnprintf(buf, PAGE_SIZE, "%d\n", msc->wrap);
1832}
1833
1834static ssize_t
1835wrap_store(struct device *dev, struct device_attribute *attr, const char *buf,
1836	   size_t size)
1837{
1838	struct msc *msc = dev_get_drvdata(dev);
1839	unsigned long val;
1840	int ret;
1841
1842	ret = kstrtoul(buf, 10, &val);
1843	if (ret)
1844		return ret;
1845
1846	msc->wrap = !!val;
1847
1848	return size;
1849}
1850
1851static DEVICE_ATTR_RW(wrap);
1852
1853static void msc_buffer_unassign(struct msc *msc)
1854{
1855	lockdep_assert_held(&msc->buf_mutex);
1856
1857	if (!msc->mbuf)
1858		return;
1859
1860	msc->mbuf->unassign(msc->mbuf_priv);
1861	msu_buffer_put(msc->mbuf);
1862	msc->mbuf_priv = NULL;
1863	msc->mbuf = NULL;
1864}
1865
1866static ssize_t
1867mode_show(struct device *dev, struct device_attribute *attr, char *buf)
1868{
1869	struct msc *msc = dev_get_drvdata(dev);
1870	const char *mode = msc_mode[msc->mode];
1871	ssize_t ret;
1872
1873	mutex_lock(&msc->buf_mutex);
1874	if (msc->mbuf)
1875		mode = msc->mbuf->name;
1876	ret = scnprintf(buf, PAGE_SIZE, "%s\n", mode);
1877	mutex_unlock(&msc->buf_mutex);
1878
1879	return ret;
1880}
1881
1882static ssize_t
1883mode_store(struct device *dev, struct device_attribute *attr, const char *buf,
1884	   size_t size)
1885{
1886	const struct msu_buffer *mbuf = NULL;
1887	struct msc *msc = dev_get_drvdata(dev);
1888	size_t len = size;
1889	char *cp, *mode;
1890	int i, ret;
1891
1892	if (!capable(CAP_SYS_RAWIO))
1893		return -EPERM;
1894
1895	cp = memchr(buf, '\n', len);
1896	if (cp)
1897		len = cp - buf;
1898
1899	mode = kstrndup(buf, len, GFP_KERNEL);
1900	if (!mode)
1901		return -ENOMEM;
1902
1903	i = match_string(msc_mode, ARRAY_SIZE(msc_mode), mode);
1904	if (i >= 0) {
1905		kfree(mode);
1906		goto found;
1907	}
1908
1909	/* Buffer sinks only work with a usable IRQ */
1910	if (!msc->do_irq) {
1911		kfree(mode);
1912		return -EINVAL;
1913	}
1914
1915	mbuf = msu_buffer_get(mode);
1916	kfree(mode);
1917	if (mbuf)
1918		goto found;
1919
1920	return -EINVAL;
1921
1922found:
1923	if (i == MSC_MODE_MULTI && msc->multi_is_broken)
1924		return -EOPNOTSUPP;
1925
1926	mutex_lock(&msc->buf_mutex);
1927	ret = 0;
1928
1929	/* Same buffer: do nothing */
1930	if (mbuf && mbuf == msc->mbuf) {
1931		/* put the extra reference we just got */
1932		msu_buffer_put(mbuf);
1933		goto unlock;
1934	}
1935
1936	ret = msc_buffer_unlocked_free_unless_used(msc);
1937	if (ret)
1938		goto unlock;
1939
1940	if (mbuf) {
1941		void *mbuf_priv = mbuf->assign(dev, &i);
1942
1943		if (!mbuf_priv) {
1944			ret = -ENOMEM;
1945			goto unlock;
1946		}
1947
1948		msc_buffer_unassign(msc);
1949		msc->mbuf_priv = mbuf_priv;
1950		msc->mbuf = mbuf;
1951	} else {
1952		msc_buffer_unassign(msc);
1953	}
1954
1955	msc->mode = i;
1956
1957unlock:
1958	if (ret && mbuf)
1959		msu_buffer_put(mbuf);
1960	mutex_unlock(&msc->buf_mutex);
1961
1962	return ret ? ret : size;
1963}
1964
1965static DEVICE_ATTR_RW(mode);
1966
1967static ssize_t
1968nr_pages_show(struct device *dev, struct device_attribute *attr, char *buf)
1969{
1970	struct msc *msc = dev_get_drvdata(dev);
1971	struct msc_window *win;
1972	size_t count = 0;
1973
1974	mutex_lock(&msc->buf_mutex);
1975
1976	if (msc->mode == MSC_MODE_SINGLE)
1977		count = scnprintf(buf, PAGE_SIZE, "%ld\n", msc->nr_pages);
1978	else if (msc->mode == MSC_MODE_MULTI) {
1979		list_for_each_entry(win, &msc->win_list, entry) {
1980			count += scnprintf(buf + count, PAGE_SIZE - count,
1981					   "%d%c", win->nr_blocks,
1982					   msc_is_last_win(win) ? '\n' : ',');
1983		}
1984	} else {
1985		count = scnprintf(buf, PAGE_SIZE, "unsupported\n");
1986	}
1987
1988	mutex_unlock(&msc->buf_mutex);
1989
1990	return count;
1991}
1992
1993static ssize_t
1994nr_pages_store(struct device *dev, struct device_attribute *attr,
1995	       const char *buf, size_t size)
1996{
1997	struct msc *msc = dev_get_drvdata(dev);
1998	unsigned long val, *win = NULL, *rewin;
1999	size_t len = size;
2000	const char *p = buf;
2001	char *end, *s;
2002	int ret, nr_wins = 0;
2003
2004	if (!capable(CAP_SYS_RAWIO))
2005		return -EPERM;
2006
2007	ret = msc_buffer_free_unless_used(msc);
2008	if (ret)
2009		return ret;
2010
2011	/* scan the comma-separated list of allocation sizes */
2012	end = memchr(buf, '\n', len);
2013	if (end)
2014		len = end - buf;
2015
2016	do {
2017		end = memchr(p, ',', len);
2018		s = kstrndup(p, end ? end - p : len, GFP_KERNEL);
2019		if (!s) {
2020			ret = -ENOMEM;
2021			goto free_win;
2022		}
2023
2024		ret = kstrtoul(s, 10, &val);
2025		kfree(s);
2026
2027		if (ret || !val)
2028			goto free_win;
2029
2030		if (nr_wins && msc->mode == MSC_MODE_SINGLE) {
2031			ret = -EINVAL;
2032			goto free_win;
2033		}
2034
2035		nr_wins++;
2036		rewin = krealloc_array(win, nr_wins, sizeof(*win), GFP_KERNEL);
2037		if (!rewin) {
2038			kfree(win);
2039			return -ENOMEM;
2040		}
2041
2042		win = rewin;
2043		win[nr_wins - 1] = val;
2044
2045		if (!end)
2046			break;
2047
2048		/* consume the number and the following comma, hence +1 */
2049		len -= end - p + 1;
2050		p = end + 1;
2051	} while (len);
2052
2053	mutex_lock(&msc->buf_mutex);
2054	ret = msc_buffer_alloc(msc, win, nr_wins);
2055	mutex_unlock(&msc->buf_mutex);
2056
2057free_win:
2058	kfree(win);
2059
2060	return ret ? ret : size;
2061}
2062
2063static DEVICE_ATTR_RW(nr_pages);
2064
2065static ssize_t
2066win_switch_store(struct device *dev, struct device_attribute *attr,
2067		 const char *buf, size_t size)
2068{
2069	struct msc *msc = dev_get_drvdata(dev);
2070	unsigned long val;
2071	int ret;
2072
2073	ret = kstrtoul(buf, 10, &val);
2074	if (ret)
2075		return ret;
2076
2077	if (val != 1)
2078		return -EINVAL;
2079
2080	ret = -EINVAL;
2081	mutex_lock(&msc->buf_mutex);
2082	/*
2083	 * Window switch can only happen in the "multi" mode.
2084	 * If a external buffer is engaged, they have the full
2085	 * control over window switching.
2086	 */
2087	if (msc->mode == MSC_MODE_MULTI && !msc->mbuf)
2088		ret = msc_win_switch(msc);
 
 
2089	mutex_unlock(&msc->buf_mutex);
2090
2091	return ret ? ret : size;
2092}
2093
2094static DEVICE_ATTR_WO(win_switch);
2095
2096static ssize_t stop_on_full_show(struct device *dev,
2097				 struct device_attribute *attr, char *buf)
2098{
2099	struct msc *msc = dev_get_drvdata(dev);
2100
2101	return sprintf(buf, "%d\n", msc->stop_on_full);
2102}
2103
2104static ssize_t stop_on_full_store(struct device *dev,
2105				  struct device_attribute *attr,
2106				  const char *buf, size_t size)
2107{
2108	struct msc *msc = dev_get_drvdata(dev);
2109	int ret;
2110
2111	ret = kstrtobool(buf, &msc->stop_on_full);
2112	if (ret)
2113		return ret;
2114
2115	return size;
2116}
2117
2118static DEVICE_ATTR_RW(stop_on_full);
2119
2120static struct attribute *msc_output_attrs[] = {
2121	&dev_attr_wrap.attr,
2122	&dev_attr_mode.attr,
2123	&dev_attr_nr_pages.attr,
2124	&dev_attr_win_switch.attr,
2125	&dev_attr_stop_on_full.attr,
2126	NULL,
2127};
2128
2129static const struct attribute_group msc_output_group = {
2130	.attrs	= msc_output_attrs,
2131};
2132
2133static int intel_th_msc_probe(struct intel_th_device *thdev)
2134{
2135	struct device *dev = &thdev->dev;
2136	struct resource *res;
2137	struct msc *msc;
2138	void __iomem *base;
2139	int err;
2140
2141	res = intel_th_device_get_resource(thdev, IORESOURCE_MEM, 0);
2142	if (!res)
2143		return -ENODEV;
2144
2145	base = devm_ioremap(dev, res->start, resource_size(res));
2146	if (!base)
2147		return -ENOMEM;
2148
2149	msc = devm_kzalloc(dev, sizeof(*msc), GFP_KERNEL);
2150	if (!msc)
2151		return -ENOMEM;
2152
2153	res = intel_th_device_get_resource(thdev, IORESOURCE_IRQ, 1);
2154	if (!res)
2155		msc->do_irq = 1;
2156
2157	if (INTEL_TH_CAP(to_intel_th(thdev), multi_is_broken))
2158		msc->multi_is_broken = 1;
2159
2160	msc->index = thdev->id;
2161
2162	msc->thdev = thdev;
2163	msc->reg_base = base + msc->index * 0x100;
2164	msc->msu_base = base;
2165
2166	INIT_WORK(&msc->work, msc_work);
2167	err = intel_th_msc_init(msc);
2168	if (err)
2169		return err;
2170
2171	dev_set_drvdata(dev, msc);
2172
2173	return 0;
2174}
2175
2176static void intel_th_msc_remove(struct intel_th_device *thdev)
2177{
2178	struct msc *msc = dev_get_drvdata(&thdev->dev);
2179	int ret;
2180
2181	intel_th_msc_deactivate(thdev);
2182
2183	/*
2184	 * Buffers should not be used at this point except if the
2185	 * output character device is still open and the parent
2186	 * device gets detached from its bus, which is a FIXME.
2187	 */
2188	ret = msc_buffer_free_unless_used(msc);
2189	WARN_ON_ONCE(ret);
2190}
2191
2192static struct intel_th_driver intel_th_msc_driver = {
2193	.probe	= intel_th_msc_probe,
2194	.remove	= intel_th_msc_remove,
2195	.irq		= intel_th_msc_interrupt,
2196	.wait_empty	= intel_th_msc_wait_empty,
2197	.activate	= intel_th_msc_activate,
2198	.deactivate	= intel_th_msc_deactivate,
2199	.fops	= &intel_th_msc_fops,
2200	.attr_group	= &msc_output_group,
2201	.driver	= {
2202		.name	= "msc",
2203		.owner	= THIS_MODULE,
2204	},
2205};
2206
2207module_driver(intel_th_msc_driver,
2208	      intel_th_driver_register,
2209	      intel_th_driver_unregister);
2210
2211MODULE_LICENSE("GPL v2");
2212MODULE_DESCRIPTION("Intel(R) Trace Hub Memory Storage Unit driver");
2213MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@linux.intel.com>");