Loading...
Note: File does not exist in v3.15.
1/*
2 * Intel(R) Trace Hub Memory Storage Unit
3 *
4 * Copyright (C) 2014-2015 Intel Corporation.
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms and conditions of the GNU General Public License,
8 * version 2, as published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
13 * more details.
14 */
15
16#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
17
18#include <linux/types.h>
19#include <linux/module.h>
20#include <linux/device.h>
21#include <linux/uaccess.h>
22#include <linux/sizes.h>
23#include <linux/printk.h>
24#include <linux/slab.h>
25#include <linux/mm.h>
26#include <linux/fs.h>
27#include <linux/io.h>
28#include <linux/dma-mapping.h>
29
30#include <asm/cacheflush.h>
31
32#include "intel_th.h"
33#include "msu.h"
34
35#define msc_dev(x) (&(x)->thdev->dev)
36
37/**
38 * struct msc_block - multiblock mode block descriptor
39 * @bdesc: pointer to hardware descriptor (beginning of the block)
40 * @addr: physical address of the block
41 */
42struct msc_block {
43 struct msc_block_desc *bdesc;
44 dma_addr_t addr;
45};
46
47/**
48 * struct msc_window - multiblock mode window descriptor
49 * @entry: window list linkage (msc::win_list)
50 * @pgoff: page offset into the buffer that this window starts at
51 * @nr_blocks: number of blocks (pages) in this window
52 * @block: array of block descriptors
53 */
54struct msc_window {
55 struct list_head entry;
56 unsigned long pgoff;
57 unsigned int nr_blocks;
58 struct msc *msc;
59 struct msc_block block[0];
60};
61
62/**
63 * struct msc_iter - iterator for msc buffer
64 * @entry: msc::iter_list linkage
65 * @msc: pointer to the MSC device
66 * @start_win: oldest window
67 * @win: current window
68 * @offset: current logical offset into the buffer
69 * @start_block: oldest block in the window
70 * @block: block number in the window
71 * @block_off: offset into current block
72 * @wrap_count: block wrapping handling
73 * @eof: end of buffer reached
74 */
75struct msc_iter {
76 struct list_head entry;
77 struct msc *msc;
78 struct msc_window *start_win;
79 struct msc_window *win;
80 unsigned long offset;
81 int start_block;
82 int block;
83 unsigned int block_off;
84 unsigned int wrap_count;
85 unsigned int eof;
86};
87
88/**
89 * struct msc - MSC device representation
90 * @reg_base: register window base address
91 * @thdev: intel_th_device pointer
92 * @win_list: list of windows in multiblock mode
93 * @nr_pages: total number of pages allocated for this buffer
94 * @single_sz: amount of data in single mode
95 * @single_wrap: single mode wrap occurred
96 * @base: buffer's base pointer
97 * @base_addr: buffer's base address
98 * @user_count: number of users of the buffer
99 * @mmap_count: number of mappings
100 * @buf_mutex: mutex to serialize access to buffer-related bits
101
102 * @enabled: MSC is enabled
103 * @wrap: wrapping is enabled
104 * @mode: MSC operating mode
105 * @burst_len: write burst length
106 * @index: number of this MSC in the MSU
107 */
108struct msc {
109 void __iomem *reg_base;
110 struct intel_th_device *thdev;
111
112 struct list_head win_list;
113 unsigned long nr_pages;
114 unsigned long single_sz;
115 unsigned int single_wrap : 1;
116 void *base;
117 dma_addr_t base_addr;
118
119 /* <0: no buffer, 0: no users, >0: active users */
120 atomic_t user_count;
121
122 atomic_t mmap_count;
123 struct mutex buf_mutex;
124
125 struct list_head iter_list;
126
127 /* config */
128 unsigned int enabled : 1,
129 wrap : 1;
130 unsigned int mode;
131 unsigned int burst_len;
132 unsigned int index;
133};
134
135static inline bool msc_block_is_empty(struct msc_block_desc *bdesc)
136{
137 /* header hasn't been written */
138 if (!bdesc->valid_dw)
139 return true;
140
141 /* valid_dw includes the header */
142 if (!msc_data_sz(bdesc))
143 return true;
144
145 return false;
146}
147
148/**
149 * msc_oldest_window() - locate the window with oldest data
150 * @msc: MSC device
151 *
152 * This should only be used in multiblock mode. Caller should hold the
153 * msc::user_count reference.
154 *
155 * Return: the oldest window with valid data
156 */
157static struct msc_window *msc_oldest_window(struct msc *msc)
158{
159 struct msc_window *win;
160 u32 reg = ioread32(msc->reg_base + REG_MSU_MSC0NWSA);
161 unsigned long win_addr = (unsigned long)reg << PAGE_SHIFT;
162 unsigned int found = 0;
163
164 if (list_empty(&msc->win_list))
165 return NULL;
166
167 /*
168 * we might need a radix tree for this, depending on how
169 * many windows a typical user would allocate; ideally it's
170 * something like 2, in which case we're good
171 */
172 list_for_each_entry(win, &msc->win_list, entry) {
173 if (win->block[0].addr == win_addr)
174 found++;
175
176 /* skip the empty ones */
177 if (msc_block_is_empty(win->block[0].bdesc))
178 continue;
179
180 if (found)
181 return win;
182 }
183
184 return list_entry(msc->win_list.next, struct msc_window, entry);
185}
186
187/**
188 * msc_win_oldest_block() - locate the oldest block in a given window
189 * @win: window to look at
190 *
191 * Return: index of the block with the oldest data
192 */
193static unsigned int msc_win_oldest_block(struct msc_window *win)
194{
195 unsigned int blk;
196 struct msc_block_desc *bdesc = win->block[0].bdesc;
197
198 /* without wrapping, first block is the oldest */
199 if (!msc_block_wrapped(bdesc))
200 return 0;
201
202 /*
203 * with wrapping, last written block contains both the newest and the
204 * oldest data for this window.
205 */
206 for (blk = 0; blk < win->nr_blocks; blk++) {
207 bdesc = win->block[blk].bdesc;
208
209 if (msc_block_last_written(bdesc))
210 return blk;
211 }
212
213 return 0;
214}
215
216/**
217 * msc_is_last_win() - check if a window is the last one for a given MSC
218 * @win: window
219 * Return: true if @win is the last window in MSC's multiblock buffer
220 */
221static inline bool msc_is_last_win(struct msc_window *win)
222{
223 return win->entry.next == &win->msc->win_list;
224}
225
226/**
227 * msc_next_window() - return next window in the multiblock buffer
228 * @win: current window
229 *
230 * Return: window following the current one
231 */
232static struct msc_window *msc_next_window(struct msc_window *win)
233{
234 if (msc_is_last_win(win))
235 return list_entry(win->msc->win_list.next, struct msc_window,
236 entry);
237
238 return list_entry(win->entry.next, struct msc_window, entry);
239}
240
241static struct msc_block_desc *msc_iter_bdesc(struct msc_iter *iter)
242{
243 return iter->win->block[iter->block].bdesc;
244}
245
246static void msc_iter_init(struct msc_iter *iter)
247{
248 memset(iter, 0, sizeof(*iter));
249 iter->start_block = -1;
250 iter->block = -1;
251}
252
253static struct msc_iter *msc_iter_install(struct msc *msc)
254{
255 struct msc_iter *iter;
256
257 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
258 if (!iter)
259 return ERR_PTR(-ENOMEM);
260
261 mutex_lock(&msc->buf_mutex);
262
263 /*
264 * Reading and tracing are mutually exclusive; if msc is
265 * enabled, open() will fail; otherwise existing readers
266 * will prevent enabling the msc and the rest of fops don't
267 * need to worry about it.
268 */
269 if (msc->enabled) {
270 kfree(iter);
271 iter = ERR_PTR(-EBUSY);
272 goto unlock;
273 }
274
275 msc_iter_init(iter);
276 iter->msc = msc;
277
278 list_add_tail(&iter->entry, &msc->iter_list);
279unlock:
280 mutex_unlock(&msc->buf_mutex);
281
282 return iter;
283}
284
285static void msc_iter_remove(struct msc_iter *iter, struct msc *msc)
286{
287 mutex_lock(&msc->buf_mutex);
288 list_del(&iter->entry);
289 mutex_unlock(&msc->buf_mutex);
290
291 kfree(iter);
292}
293
294static void msc_iter_block_start(struct msc_iter *iter)
295{
296 if (iter->start_block != -1)
297 return;
298
299 iter->start_block = msc_win_oldest_block(iter->win);
300 iter->block = iter->start_block;
301 iter->wrap_count = 0;
302
303 /*
304 * start with the block with oldest data; if data has wrapped
305 * in this window, it should be in this block
306 */
307 if (msc_block_wrapped(msc_iter_bdesc(iter)))
308 iter->wrap_count = 2;
309
310}
311
312static int msc_iter_win_start(struct msc_iter *iter, struct msc *msc)
313{
314 /* already started, nothing to do */
315 if (iter->start_win)
316 return 0;
317
318 iter->start_win = msc_oldest_window(msc);
319 if (!iter->start_win)
320 return -EINVAL;
321
322 iter->win = iter->start_win;
323 iter->start_block = -1;
324
325 msc_iter_block_start(iter);
326
327 return 0;
328}
329
330static int msc_iter_win_advance(struct msc_iter *iter)
331{
332 iter->win = msc_next_window(iter->win);
333 iter->start_block = -1;
334
335 if (iter->win == iter->start_win) {
336 iter->eof++;
337 return 1;
338 }
339
340 msc_iter_block_start(iter);
341
342 return 0;
343}
344
345static int msc_iter_block_advance(struct msc_iter *iter)
346{
347 iter->block_off = 0;
348
349 /* wrapping */
350 if (iter->wrap_count && iter->block == iter->start_block) {
351 iter->wrap_count--;
352 if (!iter->wrap_count)
353 /* copied newest data from the wrapped block */
354 return msc_iter_win_advance(iter);
355 }
356
357 /* no wrapping, check for last written block */
358 if (!iter->wrap_count && msc_block_last_written(msc_iter_bdesc(iter)))
359 /* copied newest data for the window */
360 return msc_iter_win_advance(iter);
361
362 /* block advance */
363 if (++iter->block == iter->win->nr_blocks)
364 iter->block = 0;
365
366 /* no wrapping, sanity check in case there is no last written block */
367 if (!iter->wrap_count && iter->block == iter->start_block)
368 return msc_iter_win_advance(iter);
369
370 return 0;
371}
372
373/**
374 * msc_buffer_iterate() - go through multiblock buffer's data
375 * @iter: iterator structure
376 * @size: amount of data to scan
377 * @data: callback's private data
378 * @fn: iterator callback
379 *
380 * This will start at the window which will be written to next (containing
381 * the oldest data) and work its way to the current window, calling @fn
382 * for each chunk of data as it goes.
383 *
384 * Caller should have msc::user_count reference to make sure the buffer
385 * doesn't disappear from under us.
386 *
387 * Return: amount of data actually scanned.
388 */
389static ssize_t
390msc_buffer_iterate(struct msc_iter *iter, size_t size, void *data,
391 unsigned long (*fn)(void *, void *, size_t))
392{
393 struct msc *msc = iter->msc;
394 size_t len = size;
395 unsigned int advance;
396
397 if (iter->eof)
398 return 0;
399
400 /* start with the oldest window */
401 if (msc_iter_win_start(iter, msc))
402 return 0;
403
404 do {
405 unsigned long data_bytes = msc_data_sz(msc_iter_bdesc(iter));
406 void *src = (void *)msc_iter_bdesc(iter) + MSC_BDESC;
407 size_t tocopy = data_bytes, copied = 0;
408 size_t remaining = 0;
409
410 advance = 1;
411
412 /*
413 * If block wrapping happened, we need to visit the last block
414 * twice, because it contains both the oldest and the newest
415 * data in this window.
416 *
417 * First time (wrap_count==2), in the very beginning, to collect
418 * the oldest data, which is in the range
419 * (data_bytes..DATA_IN_PAGE).
420 *
421 * Second time (wrap_count==1), it's just like any other block,
422 * containing data in the range of [MSC_BDESC..data_bytes].
423 */
424 if (iter->block == iter->start_block && iter->wrap_count == 2) {
425 tocopy = DATA_IN_PAGE - data_bytes;
426 src += data_bytes;
427 }
428
429 if (!tocopy)
430 goto next_block;
431
432 tocopy -= iter->block_off;
433 src += iter->block_off;
434
435 if (len < tocopy) {
436 tocopy = len;
437 advance = 0;
438 }
439
440 remaining = fn(data, src, tocopy);
441
442 if (remaining)
443 advance = 0;
444
445 copied = tocopy - remaining;
446 len -= copied;
447 iter->block_off += copied;
448 iter->offset += copied;
449
450 if (!advance)
451 break;
452
453next_block:
454 if (msc_iter_block_advance(iter))
455 break;
456
457 } while (len);
458
459 return size - len;
460}
461
462/**
463 * msc_buffer_clear_hw_header() - clear hw header for multiblock
464 * @msc: MSC device
465 */
466static void msc_buffer_clear_hw_header(struct msc *msc)
467{
468 struct msc_window *win;
469
470 list_for_each_entry(win, &msc->win_list, entry) {
471 unsigned int blk;
472 size_t hw_sz = sizeof(struct msc_block_desc) -
473 offsetof(struct msc_block_desc, hw_tag);
474
475 for (blk = 0; blk < win->nr_blocks; blk++) {
476 struct msc_block_desc *bdesc = win->block[blk].bdesc;
477
478 memset(&bdesc->hw_tag, 0, hw_sz);
479 }
480 }
481}
482
483/**
484 * msc_configure() - set up MSC hardware
485 * @msc: the MSC device to configure
486 *
487 * Program storage mode, wrapping, burst length and trace buffer address
488 * into a given MSC. Then, enable tracing and set msc::enabled.
489 * The latter is serialized on msc::buf_mutex, so make sure to hold it.
490 */
491static int msc_configure(struct msc *msc)
492{
493 u32 reg;
494
495 lockdep_assert_held(&msc->buf_mutex);
496
497 if (msc->mode > MSC_MODE_MULTI)
498 return -ENOTSUPP;
499
500 if (msc->mode == MSC_MODE_MULTI)
501 msc_buffer_clear_hw_header(msc);
502
503 reg = msc->base_addr >> PAGE_SHIFT;
504 iowrite32(reg, msc->reg_base + REG_MSU_MSC0BAR);
505
506 if (msc->mode == MSC_MODE_SINGLE) {
507 reg = msc->nr_pages;
508 iowrite32(reg, msc->reg_base + REG_MSU_MSC0SIZE);
509 }
510
511 reg = ioread32(msc->reg_base + REG_MSU_MSC0CTL);
512 reg &= ~(MSC_MODE | MSC_WRAPEN | MSC_EN | MSC_RD_HDR_OVRD);
513
514 reg |= MSC_EN;
515 reg |= msc->mode << __ffs(MSC_MODE);
516 reg |= msc->burst_len << __ffs(MSC_LEN);
517
518 if (msc->wrap)
519 reg |= MSC_WRAPEN;
520
521 iowrite32(reg, msc->reg_base + REG_MSU_MSC0CTL);
522
523 msc->thdev->output.multiblock = msc->mode == MSC_MODE_MULTI;
524 intel_th_trace_enable(msc->thdev);
525 msc->enabled = 1;
526
527
528 return 0;
529}
530
531/**
532 * msc_disable() - disable MSC hardware
533 * @msc: MSC device to disable
534 *
535 * If @msc is enabled, disable tracing on the switch and then disable MSC
536 * storage. Caller must hold msc::buf_mutex.
537 */
538static void msc_disable(struct msc *msc)
539{
540 unsigned long count;
541 u32 reg;
542
543 lockdep_assert_held(&msc->buf_mutex);
544
545 intel_th_trace_disable(msc->thdev);
546
547 for (reg = 0, count = MSC_PLE_WAITLOOP_DEPTH;
548 count && !(reg & MSCSTS_PLE); count--) {
549 reg = ioread32(msc->reg_base + REG_MSU_MSC0STS);
550 cpu_relax();
551 }
552
553 if (!count)
554 dev_dbg(msc_dev(msc), "timeout waiting for MSC0 PLE\n");
555
556 if (msc->mode == MSC_MODE_SINGLE) {
557 msc->single_wrap = !!(reg & MSCSTS_WRAPSTAT);
558
559 reg = ioread32(msc->reg_base + REG_MSU_MSC0MWP);
560 msc->single_sz = reg & ((msc->nr_pages << PAGE_SHIFT) - 1);
561 dev_dbg(msc_dev(msc), "MSCnMWP: %08x/%08lx, wrap: %d\n",
562 reg, msc->single_sz, msc->single_wrap);
563 }
564
565 reg = ioread32(msc->reg_base + REG_MSU_MSC0CTL);
566 reg &= ~MSC_EN;
567 iowrite32(reg, msc->reg_base + REG_MSU_MSC0CTL);
568 msc->enabled = 0;
569
570 iowrite32(0, msc->reg_base + REG_MSU_MSC0BAR);
571 iowrite32(0, msc->reg_base + REG_MSU_MSC0SIZE);
572
573 dev_dbg(msc_dev(msc), "MSCnNWSA: %08x\n",
574 ioread32(msc->reg_base + REG_MSU_MSC0NWSA));
575
576 reg = ioread32(msc->reg_base + REG_MSU_MSC0STS);
577 dev_dbg(msc_dev(msc), "MSCnSTS: %08x\n", reg);
578}
579
580static int intel_th_msc_activate(struct intel_th_device *thdev)
581{
582 struct msc *msc = dev_get_drvdata(&thdev->dev);
583 int ret = -EBUSY;
584
585 if (!atomic_inc_unless_negative(&msc->user_count))
586 return -ENODEV;
587
588 mutex_lock(&msc->buf_mutex);
589
590 /* if there are readers, refuse */
591 if (list_empty(&msc->iter_list))
592 ret = msc_configure(msc);
593
594 mutex_unlock(&msc->buf_mutex);
595
596 if (ret)
597 atomic_dec(&msc->user_count);
598
599 return ret;
600}
601
602static void intel_th_msc_deactivate(struct intel_th_device *thdev)
603{
604 struct msc *msc = dev_get_drvdata(&thdev->dev);
605
606 mutex_lock(&msc->buf_mutex);
607 if (msc->enabled) {
608 msc_disable(msc);
609 atomic_dec(&msc->user_count);
610 }
611 mutex_unlock(&msc->buf_mutex);
612}
613
614/**
615 * msc_buffer_contig_alloc() - allocate a contiguous buffer for SINGLE mode
616 * @msc: MSC device
617 * @size: allocation size in bytes
618 *
619 * This modifies msc::base, which requires msc::buf_mutex to serialize, so the
620 * caller is expected to hold it.
621 *
622 * Return: 0 on success, -errno otherwise.
623 */
624static int msc_buffer_contig_alloc(struct msc *msc, unsigned long size)
625{
626 unsigned int order = get_order(size);
627 struct page *page;
628
629 if (!size)
630 return 0;
631
632 page = alloc_pages(GFP_KERNEL | __GFP_ZERO, order);
633 if (!page)
634 return -ENOMEM;
635
636 split_page(page, order);
637 msc->nr_pages = size >> PAGE_SHIFT;
638 msc->base = page_address(page);
639 msc->base_addr = page_to_phys(page);
640
641 return 0;
642}
643
644/**
645 * msc_buffer_contig_free() - free a contiguous buffer
646 * @msc: MSC configured in SINGLE mode
647 */
648static void msc_buffer_contig_free(struct msc *msc)
649{
650 unsigned long off;
651
652 for (off = 0; off < msc->nr_pages << PAGE_SHIFT; off += PAGE_SIZE) {
653 struct page *page = virt_to_page(msc->base + off);
654
655 page->mapping = NULL;
656 __free_page(page);
657 }
658
659 msc->nr_pages = 0;
660}
661
662/**
663 * msc_buffer_contig_get_page() - find a page at a given offset
664 * @msc: MSC configured in SINGLE mode
665 * @pgoff: page offset
666 *
667 * Return: page, if @pgoff is within the range, NULL otherwise.
668 */
669static struct page *msc_buffer_contig_get_page(struct msc *msc,
670 unsigned long pgoff)
671{
672 if (pgoff >= msc->nr_pages)
673 return NULL;
674
675 return virt_to_page(msc->base + (pgoff << PAGE_SHIFT));
676}
677
678/**
679 * msc_buffer_win_alloc() - alloc a window for a multiblock mode
680 * @msc: MSC device
681 * @nr_blocks: number of pages in this window
682 *
683 * This modifies msc::win_list and msc::base, which requires msc::buf_mutex
684 * to serialize, so the caller is expected to hold it.
685 *
686 * Return: 0 on success, -errno otherwise.
687 */
688static int msc_buffer_win_alloc(struct msc *msc, unsigned int nr_blocks)
689{
690 struct msc_window *win;
691 unsigned long size = PAGE_SIZE;
692 int i, ret = -ENOMEM;
693
694 if (!nr_blocks)
695 return 0;
696
697 win = kzalloc(offsetof(struct msc_window, block[nr_blocks]),
698 GFP_KERNEL);
699 if (!win)
700 return -ENOMEM;
701
702 if (!list_empty(&msc->win_list)) {
703 struct msc_window *prev = list_entry(msc->win_list.prev,
704 struct msc_window, entry);
705
706 win->pgoff = prev->pgoff + prev->nr_blocks;
707 }
708
709 for (i = 0; i < nr_blocks; i++) {
710 win->block[i].bdesc = dma_alloc_coherent(msc_dev(msc), size,
711 &win->block[i].addr,
712 GFP_KERNEL);
713
714#ifdef CONFIG_X86
715 /* Set the page as uncached */
716 set_memory_uc((unsigned long)win->block[i].bdesc, 1);
717#endif
718
719 if (!win->block[i].bdesc)
720 goto err_nomem;
721 }
722
723 win->msc = msc;
724 win->nr_blocks = nr_blocks;
725
726 if (list_empty(&msc->win_list)) {
727 msc->base = win->block[0].bdesc;
728 msc->base_addr = win->block[0].addr;
729 }
730
731 list_add_tail(&win->entry, &msc->win_list);
732 msc->nr_pages += nr_blocks;
733
734 return 0;
735
736err_nomem:
737 for (i--; i >= 0; i--) {
738#ifdef CONFIG_X86
739 /* Reset the page to write-back before releasing */
740 set_memory_wb((unsigned long)win->block[i].bdesc, 1);
741#endif
742 dma_free_coherent(msc_dev(msc), size, win->block[i].bdesc,
743 win->block[i].addr);
744 }
745 kfree(win);
746
747 return ret;
748}
749
750/**
751 * msc_buffer_win_free() - free a window from MSC's window list
752 * @msc: MSC device
753 * @win: window to free
754 *
755 * This modifies msc::win_list and msc::base, which requires msc::buf_mutex
756 * to serialize, so the caller is expected to hold it.
757 */
758static void msc_buffer_win_free(struct msc *msc, struct msc_window *win)
759{
760 int i;
761
762 msc->nr_pages -= win->nr_blocks;
763
764 list_del(&win->entry);
765 if (list_empty(&msc->win_list)) {
766 msc->base = NULL;
767 msc->base_addr = 0;
768 }
769
770 for (i = 0; i < win->nr_blocks; i++) {
771 struct page *page = virt_to_page(win->block[i].bdesc);
772
773 page->mapping = NULL;
774#ifdef CONFIG_X86
775 /* Reset the page to write-back before releasing */
776 set_memory_wb((unsigned long)win->block[i].bdesc, 1);
777#endif
778 dma_free_coherent(msc_dev(win->msc), PAGE_SIZE,
779 win->block[i].bdesc, win->block[i].addr);
780 }
781
782 kfree(win);
783}
784
785/**
786 * msc_buffer_relink() - set up block descriptors for multiblock mode
787 * @msc: MSC device
788 *
789 * This traverses msc::win_list, which requires msc::buf_mutex to serialize,
790 * so the caller is expected to hold it.
791 */
792static void msc_buffer_relink(struct msc *msc)
793{
794 struct msc_window *win, *next_win;
795
796 /* call with msc::mutex locked */
797 list_for_each_entry(win, &msc->win_list, entry) {
798 unsigned int blk;
799 u32 sw_tag = 0;
800
801 /*
802 * Last window's next_win should point to the first window
803 * and MSC_SW_TAG_LASTWIN should be set.
804 */
805 if (msc_is_last_win(win)) {
806 sw_tag |= MSC_SW_TAG_LASTWIN;
807 next_win = list_entry(msc->win_list.next,
808 struct msc_window, entry);
809 } else {
810 next_win = list_entry(win->entry.next,
811 struct msc_window, entry);
812 }
813
814 for (blk = 0; blk < win->nr_blocks; blk++) {
815 struct msc_block_desc *bdesc = win->block[blk].bdesc;
816
817 memset(bdesc, 0, sizeof(*bdesc));
818
819 bdesc->next_win = next_win->block[0].addr >> PAGE_SHIFT;
820
821 /*
822 * Similarly to last window, last block should point
823 * to the first one.
824 */
825 if (blk == win->nr_blocks - 1) {
826 sw_tag |= MSC_SW_TAG_LASTBLK;
827 bdesc->next_blk =
828 win->block[0].addr >> PAGE_SHIFT;
829 } else {
830 bdesc->next_blk =
831 win->block[blk + 1].addr >> PAGE_SHIFT;
832 }
833
834 bdesc->sw_tag = sw_tag;
835 bdesc->block_sz = PAGE_SIZE / 64;
836 }
837 }
838
839 /*
840 * Make the above writes globally visible before tracing is
841 * enabled to make sure hardware sees them coherently.
842 */
843 wmb();
844}
845
846static void msc_buffer_multi_free(struct msc *msc)
847{
848 struct msc_window *win, *iter;
849
850 list_for_each_entry_safe(win, iter, &msc->win_list, entry)
851 msc_buffer_win_free(msc, win);
852}
853
854static int msc_buffer_multi_alloc(struct msc *msc, unsigned long *nr_pages,
855 unsigned int nr_wins)
856{
857 int ret, i;
858
859 for (i = 0; i < nr_wins; i++) {
860 ret = msc_buffer_win_alloc(msc, nr_pages[i]);
861 if (ret) {
862 msc_buffer_multi_free(msc);
863 return ret;
864 }
865 }
866
867 msc_buffer_relink(msc);
868
869 return 0;
870}
871
872/**
873 * msc_buffer_free() - free buffers for MSC
874 * @msc: MSC device
875 *
876 * Free MSC's storage buffers.
877 *
878 * This modifies msc::win_list and msc::base, which requires msc::buf_mutex to
879 * serialize, so the caller is expected to hold it.
880 */
881static void msc_buffer_free(struct msc *msc)
882{
883 if (msc->mode == MSC_MODE_SINGLE)
884 msc_buffer_contig_free(msc);
885 else if (msc->mode == MSC_MODE_MULTI)
886 msc_buffer_multi_free(msc);
887}
888
889/**
890 * msc_buffer_alloc() - allocate a buffer for MSC
891 * @msc: MSC device
892 * @size: allocation size in bytes
893 *
894 * Allocate a storage buffer for MSC, depending on the msc::mode, it will be
895 * either done via msc_buffer_contig_alloc() for SINGLE operation mode or
896 * msc_buffer_win_alloc() for multiblock operation. The latter allocates one
897 * window per invocation, so in multiblock mode this can be called multiple
898 * times for the same MSC to allocate multiple windows.
899 *
900 * This modifies msc::win_list and msc::base, which requires msc::buf_mutex
901 * to serialize, so the caller is expected to hold it.
902 *
903 * Return: 0 on success, -errno otherwise.
904 */
905static int msc_buffer_alloc(struct msc *msc, unsigned long *nr_pages,
906 unsigned int nr_wins)
907{
908 int ret;
909
910 /* -1: buffer not allocated */
911 if (atomic_read(&msc->user_count) != -1)
912 return -EBUSY;
913
914 if (msc->mode == MSC_MODE_SINGLE) {
915 if (nr_wins != 1)
916 return -EINVAL;
917
918 ret = msc_buffer_contig_alloc(msc, nr_pages[0] << PAGE_SHIFT);
919 } else if (msc->mode == MSC_MODE_MULTI) {
920 ret = msc_buffer_multi_alloc(msc, nr_pages, nr_wins);
921 } else {
922 ret = -ENOTSUPP;
923 }
924
925 if (!ret) {
926 /* allocation should be visible before the counter goes to 0 */
927 smp_mb__before_atomic();
928
929 if (WARN_ON_ONCE(atomic_cmpxchg(&msc->user_count, -1, 0) != -1))
930 return -EINVAL;
931 }
932
933 return ret;
934}
935
936/**
937 * msc_buffer_unlocked_free_unless_used() - free a buffer unless it's in use
938 * @msc: MSC device
939 *
940 * This will free MSC buffer unless it is in use or there is no allocated
941 * buffer.
942 * Caller needs to hold msc::buf_mutex.
943 *
944 * Return: 0 on successful deallocation or if there was no buffer to
945 * deallocate, -EBUSY if there are active users.
946 */
947static int msc_buffer_unlocked_free_unless_used(struct msc *msc)
948{
949 int count, ret = 0;
950
951 count = atomic_cmpxchg(&msc->user_count, 0, -1);
952
953 /* > 0: buffer is allocated and has users */
954 if (count > 0)
955 ret = -EBUSY;
956 /* 0: buffer is allocated, no users */
957 else if (!count)
958 msc_buffer_free(msc);
959 /* < 0: no buffer, nothing to do */
960
961 return ret;
962}
963
964/**
965 * msc_buffer_free_unless_used() - free a buffer unless it's in use
966 * @msc: MSC device
967 *
968 * This is a locked version of msc_buffer_unlocked_free_unless_used().
969 */
970static int msc_buffer_free_unless_used(struct msc *msc)
971{
972 int ret;
973
974 mutex_lock(&msc->buf_mutex);
975 ret = msc_buffer_unlocked_free_unless_used(msc);
976 mutex_unlock(&msc->buf_mutex);
977
978 return ret;
979}
980
981/**
982 * msc_buffer_get_page() - get MSC buffer page at a given offset
983 * @msc: MSC device
984 * @pgoff: page offset into the storage buffer
985 *
986 * This traverses msc::win_list, so holding msc::buf_mutex is expected from
987 * the caller.
988 *
989 * Return: page if @pgoff corresponds to a valid buffer page or NULL.
990 */
991static struct page *msc_buffer_get_page(struct msc *msc, unsigned long pgoff)
992{
993 struct msc_window *win;
994
995 if (msc->mode == MSC_MODE_SINGLE)
996 return msc_buffer_contig_get_page(msc, pgoff);
997
998 list_for_each_entry(win, &msc->win_list, entry)
999 if (pgoff >= win->pgoff && pgoff < win->pgoff + win->nr_blocks)
1000 goto found;
1001
1002 return NULL;
1003
1004found:
1005 pgoff -= win->pgoff;
1006 return virt_to_page(win->block[pgoff].bdesc);
1007}
1008
1009/**
1010 * struct msc_win_to_user_struct - data for copy_to_user() callback
1011 * @buf: userspace buffer to copy data to
1012 * @offset: running offset
1013 */
1014struct msc_win_to_user_struct {
1015 char __user *buf;
1016 unsigned long offset;
1017};
1018
1019/**
1020 * msc_win_to_user() - iterator for msc_buffer_iterate() to copy data to user
1021 * @data: callback's private data
1022 * @src: source buffer
1023 * @len: amount of data to copy from the source buffer
1024 */
1025static unsigned long msc_win_to_user(void *data, void *src, size_t len)
1026{
1027 struct msc_win_to_user_struct *u = data;
1028 unsigned long ret;
1029
1030 ret = copy_to_user(u->buf + u->offset, src, len);
1031 u->offset += len - ret;
1032
1033 return ret;
1034}
1035
1036
1037/*
1038 * file operations' callbacks
1039 */
1040
1041static int intel_th_msc_open(struct inode *inode, struct file *file)
1042{
1043 struct intel_th_device *thdev = file->private_data;
1044 struct msc *msc = dev_get_drvdata(&thdev->dev);
1045 struct msc_iter *iter;
1046
1047 if (!capable(CAP_SYS_RAWIO))
1048 return -EPERM;
1049
1050 iter = msc_iter_install(msc);
1051 if (IS_ERR(iter))
1052 return PTR_ERR(iter);
1053
1054 file->private_data = iter;
1055
1056 return nonseekable_open(inode, file);
1057}
1058
1059static int intel_th_msc_release(struct inode *inode, struct file *file)
1060{
1061 struct msc_iter *iter = file->private_data;
1062 struct msc *msc = iter->msc;
1063
1064 msc_iter_remove(iter, msc);
1065
1066 return 0;
1067}
1068
1069static ssize_t
1070msc_single_to_user(struct msc *msc, char __user *buf, loff_t off, size_t len)
1071{
1072 unsigned long size = msc->nr_pages << PAGE_SHIFT, rem = len;
1073 unsigned long start = off, tocopy = 0;
1074
1075 if (msc->single_wrap) {
1076 start += msc->single_sz;
1077 if (start < size) {
1078 tocopy = min(rem, size - start);
1079 if (copy_to_user(buf, msc->base + start, tocopy))
1080 return -EFAULT;
1081
1082 buf += tocopy;
1083 rem -= tocopy;
1084 start += tocopy;
1085 }
1086
1087 start &= size - 1;
1088 if (rem) {
1089 tocopy = min(rem, msc->single_sz - start);
1090 if (copy_to_user(buf, msc->base + start, tocopy))
1091 return -EFAULT;
1092
1093 rem -= tocopy;
1094 }
1095
1096 return len - rem;
1097 }
1098
1099 if (copy_to_user(buf, msc->base + start, rem))
1100 return -EFAULT;
1101
1102 return len;
1103}
1104
1105static ssize_t intel_th_msc_read(struct file *file, char __user *buf,
1106 size_t len, loff_t *ppos)
1107{
1108 struct msc_iter *iter = file->private_data;
1109 struct msc *msc = iter->msc;
1110 size_t size;
1111 loff_t off = *ppos;
1112 ssize_t ret = 0;
1113
1114 if (!atomic_inc_unless_negative(&msc->user_count))
1115 return 0;
1116
1117 if (msc->mode == MSC_MODE_SINGLE && !msc->single_wrap)
1118 size = msc->single_sz;
1119 else
1120 size = msc->nr_pages << PAGE_SHIFT;
1121
1122 if (!size)
1123 goto put_count;
1124
1125 if (off >= size)
1126 goto put_count;
1127
1128 if (off + len >= size)
1129 len = size - off;
1130
1131 if (msc->mode == MSC_MODE_SINGLE) {
1132 ret = msc_single_to_user(msc, buf, off, len);
1133 if (ret >= 0)
1134 *ppos += ret;
1135 } else if (msc->mode == MSC_MODE_MULTI) {
1136 struct msc_win_to_user_struct u = {
1137 .buf = buf,
1138 .offset = 0,
1139 };
1140
1141 ret = msc_buffer_iterate(iter, len, &u, msc_win_to_user);
1142 if (ret >= 0)
1143 *ppos = iter->offset;
1144 } else {
1145 ret = -ENOTSUPP;
1146 }
1147
1148put_count:
1149 atomic_dec(&msc->user_count);
1150
1151 return ret;
1152}
1153
1154/*
1155 * vm operations callbacks (vm_ops)
1156 */
1157
1158static void msc_mmap_open(struct vm_area_struct *vma)
1159{
1160 struct msc_iter *iter = vma->vm_file->private_data;
1161 struct msc *msc = iter->msc;
1162
1163 atomic_inc(&msc->mmap_count);
1164}
1165
1166static void msc_mmap_close(struct vm_area_struct *vma)
1167{
1168 struct msc_iter *iter = vma->vm_file->private_data;
1169 struct msc *msc = iter->msc;
1170 unsigned long pg;
1171
1172 if (!atomic_dec_and_mutex_lock(&msc->mmap_count, &msc->buf_mutex))
1173 return;
1174
1175 /* drop page _refcounts */
1176 for (pg = 0; pg < msc->nr_pages; pg++) {
1177 struct page *page = msc_buffer_get_page(msc, pg);
1178
1179 if (WARN_ON_ONCE(!page))
1180 continue;
1181
1182 if (page->mapping)
1183 page->mapping = NULL;
1184 }
1185
1186 /* last mapping -- drop user_count */
1187 atomic_dec(&msc->user_count);
1188 mutex_unlock(&msc->buf_mutex);
1189}
1190
1191static int msc_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
1192{
1193 struct msc_iter *iter = vma->vm_file->private_data;
1194 struct msc *msc = iter->msc;
1195
1196 vmf->page = msc_buffer_get_page(msc, vmf->pgoff);
1197 if (!vmf->page)
1198 return VM_FAULT_SIGBUS;
1199
1200 get_page(vmf->page);
1201 vmf->page->mapping = vma->vm_file->f_mapping;
1202 vmf->page->index = vmf->pgoff;
1203
1204 return 0;
1205}
1206
1207static const struct vm_operations_struct msc_mmap_ops = {
1208 .open = msc_mmap_open,
1209 .close = msc_mmap_close,
1210 .fault = msc_mmap_fault,
1211};
1212
1213static int intel_th_msc_mmap(struct file *file, struct vm_area_struct *vma)
1214{
1215 unsigned long size = vma->vm_end - vma->vm_start;
1216 struct msc_iter *iter = vma->vm_file->private_data;
1217 struct msc *msc = iter->msc;
1218 int ret = -EINVAL;
1219
1220 if (!size || offset_in_page(size))
1221 return -EINVAL;
1222
1223 if (vma->vm_pgoff)
1224 return -EINVAL;
1225
1226 /* grab user_count once per mmap; drop in msc_mmap_close() */
1227 if (!atomic_inc_unless_negative(&msc->user_count))
1228 return -EINVAL;
1229
1230 if (msc->mode != MSC_MODE_SINGLE &&
1231 msc->mode != MSC_MODE_MULTI)
1232 goto out;
1233
1234 if (size >> PAGE_SHIFT != msc->nr_pages)
1235 goto out;
1236
1237 atomic_set(&msc->mmap_count, 1);
1238 ret = 0;
1239
1240out:
1241 if (ret)
1242 atomic_dec(&msc->user_count);
1243
1244 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
1245 vma->vm_flags |= VM_DONTEXPAND | VM_DONTCOPY;
1246 vma->vm_ops = &msc_mmap_ops;
1247 return ret;
1248}
1249
1250static const struct file_operations intel_th_msc_fops = {
1251 .open = intel_th_msc_open,
1252 .release = intel_th_msc_release,
1253 .read = intel_th_msc_read,
1254 .mmap = intel_th_msc_mmap,
1255 .llseek = no_llseek,
1256 .owner = THIS_MODULE,
1257};
1258
1259static int intel_th_msc_init(struct msc *msc)
1260{
1261 atomic_set(&msc->user_count, -1);
1262
1263 msc->mode = MSC_MODE_MULTI;
1264 mutex_init(&msc->buf_mutex);
1265 INIT_LIST_HEAD(&msc->win_list);
1266 INIT_LIST_HEAD(&msc->iter_list);
1267
1268 msc->burst_len =
1269 (ioread32(msc->reg_base + REG_MSU_MSC0CTL) & MSC_LEN) >>
1270 __ffs(MSC_LEN);
1271
1272 return 0;
1273}
1274
1275static const char * const msc_mode[] = {
1276 [MSC_MODE_SINGLE] = "single",
1277 [MSC_MODE_MULTI] = "multi",
1278 [MSC_MODE_EXI] = "ExI",
1279 [MSC_MODE_DEBUG] = "debug",
1280};
1281
1282static ssize_t
1283wrap_show(struct device *dev, struct device_attribute *attr, char *buf)
1284{
1285 struct msc *msc = dev_get_drvdata(dev);
1286
1287 return scnprintf(buf, PAGE_SIZE, "%d\n", msc->wrap);
1288}
1289
1290static ssize_t
1291wrap_store(struct device *dev, struct device_attribute *attr, const char *buf,
1292 size_t size)
1293{
1294 struct msc *msc = dev_get_drvdata(dev);
1295 unsigned long val;
1296 int ret;
1297
1298 ret = kstrtoul(buf, 10, &val);
1299 if (ret)
1300 return ret;
1301
1302 msc->wrap = !!val;
1303
1304 return size;
1305}
1306
1307static DEVICE_ATTR_RW(wrap);
1308
1309static ssize_t
1310mode_show(struct device *dev, struct device_attribute *attr, char *buf)
1311{
1312 struct msc *msc = dev_get_drvdata(dev);
1313
1314 return scnprintf(buf, PAGE_SIZE, "%s\n", msc_mode[msc->mode]);
1315}
1316
1317static ssize_t
1318mode_store(struct device *dev, struct device_attribute *attr, const char *buf,
1319 size_t size)
1320{
1321 struct msc *msc = dev_get_drvdata(dev);
1322 size_t len = size;
1323 char *cp;
1324 int i, ret;
1325
1326 if (!capable(CAP_SYS_RAWIO))
1327 return -EPERM;
1328
1329 cp = memchr(buf, '\n', len);
1330 if (cp)
1331 len = cp - buf;
1332
1333 for (i = 0; i < ARRAY_SIZE(msc_mode); i++)
1334 if (!strncmp(msc_mode[i], buf, len))
1335 goto found;
1336
1337 return -EINVAL;
1338
1339found:
1340 mutex_lock(&msc->buf_mutex);
1341 ret = msc_buffer_unlocked_free_unless_used(msc);
1342 if (!ret)
1343 msc->mode = i;
1344 mutex_unlock(&msc->buf_mutex);
1345
1346 return ret ? ret : size;
1347}
1348
1349static DEVICE_ATTR_RW(mode);
1350
1351static ssize_t
1352nr_pages_show(struct device *dev, struct device_attribute *attr, char *buf)
1353{
1354 struct msc *msc = dev_get_drvdata(dev);
1355 struct msc_window *win;
1356 size_t count = 0;
1357
1358 mutex_lock(&msc->buf_mutex);
1359
1360 if (msc->mode == MSC_MODE_SINGLE)
1361 count = scnprintf(buf, PAGE_SIZE, "%ld\n", msc->nr_pages);
1362 else if (msc->mode == MSC_MODE_MULTI) {
1363 list_for_each_entry(win, &msc->win_list, entry) {
1364 count += scnprintf(buf + count, PAGE_SIZE - count,
1365 "%d%c", win->nr_blocks,
1366 msc_is_last_win(win) ? '\n' : ',');
1367 }
1368 } else {
1369 count = scnprintf(buf, PAGE_SIZE, "unsupported\n");
1370 }
1371
1372 mutex_unlock(&msc->buf_mutex);
1373
1374 return count;
1375}
1376
1377static ssize_t
1378nr_pages_store(struct device *dev, struct device_attribute *attr,
1379 const char *buf, size_t size)
1380{
1381 struct msc *msc = dev_get_drvdata(dev);
1382 unsigned long val, *win = NULL, *rewin;
1383 size_t len = size;
1384 const char *p = buf;
1385 char *end, *s;
1386 int ret, nr_wins = 0;
1387
1388 if (!capable(CAP_SYS_RAWIO))
1389 return -EPERM;
1390
1391 ret = msc_buffer_free_unless_used(msc);
1392 if (ret)
1393 return ret;
1394
1395 /* scan the comma-separated list of allocation sizes */
1396 end = memchr(buf, '\n', len);
1397 if (end)
1398 len = end - buf;
1399
1400 do {
1401 end = memchr(p, ',', len);
1402 s = kstrndup(p, end ? end - p : len, GFP_KERNEL);
1403 if (!s) {
1404 ret = -ENOMEM;
1405 goto free_win;
1406 }
1407
1408 ret = kstrtoul(s, 10, &val);
1409 kfree(s);
1410
1411 if (ret || !val)
1412 goto free_win;
1413
1414 if (nr_wins && msc->mode == MSC_MODE_SINGLE) {
1415 ret = -EINVAL;
1416 goto free_win;
1417 }
1418
1419 nr_wins++;
1420 rewin = krealloc(win, sizeof(*win) * nr_wins, GFP_KERNEL);
1421 if (!rewin) {
1422 kfree(win);
1423 return -ENOMEM;
1424 }
1425
1426 win = rewin;
1427 win[nr_wins - 1] = val;
1428
1429 if (!end)
1430 break;
1431
1432 len -= end - p;
1433 p = end + 1;
1434 } while (len);
1435
1436 mutex_lock(&msc->buf_mutex);
1437 ret = msc_buffer_alloc(msc, win, nr_wins);
1438 mutex_unlock(&msc->buf_mutex);
1439
1440free_win:
1441 kfree(win);
1442
1443 return ret ? ret : size;
1444}
1445
1446static DEVICE_ATTR_RW(nr_pages);
1447
1448static struct attribute *msc_output_attrs[] = {
1449 &dev_attr_wrap.attr,
1450 &dev_attr_mode.attr,
1451 &dev_attr_nr_pages.attr,
1452 NULL,
1453};
1454
1455static struct attribute_group msc_output_group = {
1456 .attrs = msc_output_attrs,
1457};
1458
1459static int intel_th_msc_probe(struct intel_th_device *thdev)
1460{
1461 struct device *dev = &thdev->dev;
1462 struct resource *res;
1463 struct msc *msc;
1464 void __iomem *base;
1465 int err;
1466
1467 res = intel_th_device_get_resource(thdev, IORESOURCE_MEM, 0);
1468 if (!res)
1469 return -ENODEV;
1470
1471 base = devm_ioremap(dev, res->start, resource_size(res));
1472 if (!base)
1473 return -ENOMEM;
1474
1475 msc = devm_kzalloc(dev, sizeof(*msc), GFP_KERNEL);
1476 if (!msc)
1477 return -ENOMEM;
1478
1479 msc->index = thdev->id;
1480
1481 msc->thdev = thdev;
1482 msc->reg_base = base + msc->index * 0x100;
1483
1484 err = intel_th_msc_init(msc);
1485 if (err)
1486 return err;
1487
1488 dev_set_drvdata(dev, msc);
1489
1490 return 0;
1491}
1492
1493static void intel_th_msc_remove(struct intel_th_device *thdev)
1494{
1495 struct msc *msc = dev_get_drvdata(&thdev->dev);
1496 int ret;
1497
1498 intel_th_msc_deactivate(thdev);
1499
1500 /*
1501 * Buffers should not be used at this point except if the
1502 * output character device is still open and the parent
1503 * device gets detached from its bus, which is a FIXME.
1504 */
1505 ret = msc_buffer_free_unless_used(msc);
1506 WARN_ON_ONCE(ret);
1507}
1508
1509static struct intel_th_driver intel_th_msc_driver = {
1510 .probe = intel_th_msc_probe,
1511 .remove = intel_th_msc_remove,
1512 .activate = intel_th_msc_activate,
1513 .deactivate = intel_th_msc_deactivate,
1514 .fops = &intel_th_msc_fops,
1515 .attr_group = &msc_output_group,
1516 .driver = {
1517 .name = "msc",
1518 .owner = THIS_MODULE,
1519 },
1520};
1521
1522module_driver(intel_th_msc_driver,
1523 intel_th_driver_register,
1524 intel_th_driver_unregister);
1525
1526MODULE_LICENSE("GPL v2");
1527MODULE_DESCRIPTION("Intel(R) Trace Hub Memory Storage Unit driver");
1528MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@linux.intel.com>");