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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 mutex iter_mutex;
126 struct list_head iter_list;
127
128 /* config */
129 unsigned int enabled : 1,
130 wrap : 1;
131 unsigned int mode;
132 unsigned int burst_len;
133 unsigned int index;
134};
135
136static inline bool msc_block_is_empty(struct msc_block_desc *bdesc)
137{
138 /* header hasn't been written */
139 if (!bdesc->valid_dw)
140 return true;
141
142 /* valid_dw includes the header */
143 if (!msc_data_sz(bdesc))
144 return true;
145
146 return false;
147}
148
149/**
150 * msc_oldest_window() - locate the window with oldest data
151 * @msc: MSC device
152 *
153 * This should only be used in multiblock mode. Caller should hold the
154 * msc::user_count reference.
155 *
156 * Return: the oldest window with valid data
157 */
158static struct msc_window *msc_oldest_window(struct msc *msc)
159{
160 struct msc_window *win;
161 u32 reg = ioread32(msc->reg_base + REG_MSU_MSC0NWSA);
162 unsigned long win_addr = (unsigned long)reg << PAGE_SHIFT;
163 unsigned int found = 0;
164
165 if (list_empty(&msc->win_list))
166 return NULL;
167
168 /*
169 * we might need a radix tree for this, depending on how
170 * many windows a typical user would allocate; ideally it's
171 * something like 2, in which case we're good
172 */
173 list_for_each_entry(win, &msc->win_list, entry) {
174 if (win->block[0].addr == win_addr)
175 found++;
176
177 /* skip the empty ones */
178 if (msc_block_is_empty(win->block[0].bdesc))
179 continue;
180
181 if (found)
182 return win;
183 }
184
185 return list_entry(msc->win_list.next, struct msc_window, entry);
186}
187
188/**
189 * msc_win_oldest_block() - locate the oldest block in a given window
190 * @win: window to look at
191 *
192 * Return: index of the block with the oldest data
193 */
194static unsigned int msc_win_oldest_block(struct msc_window *win)
195{
196 unsigned int blk;
197 struct msc_block_desc *bdesc = win->block[0].bdesc;
198
199 /* without wrapping, first block is the oldest */
200 if (!msc_block_wrapped(bdesc))
201 return 0;
202
203 /*
204 * with wrapping, last written block contains both the newest and the
205 * oldest data for this window.
206 */
207 for (blk = 0; blk < win->nr_blocks; blk++) {
208 bdesc = win->block[blk].bdesc;
209
210 if (msc_block_last_written(bdesc))
211 return blk;
212 }
213
214 return 0;
215}
216
217/**
218 * msc_is_last_win() - check if a window is the last one for a given MSC
219 * @win: window
220 * Return: true if @win is the last window in MSC's multiblock buffer
221 */
222static inline bool msc_is_last_win(struct msc_window *win)
223{
224 return win->entry.next == &win->msc->win_list;
225}
226
227/**
228 * msc_next_window() - return next window in the multiblock buffer
229 * @win: current window
230 *
231 * Return: window following the current one
232 */
233static struct msc_window *msc_next_window(struct msc_window *win)
234{
235 if (msc_is_last_win(win))
236 return list_entry(win->msc->win_list.next, struct msc_window,
237 entry);
238
239 return list_entry(win->entry.next, struct msc_window, entry);
240}
241
242static struct msc_block_desc *msc_iter_bdesc(struct msc_iter *iter)
243{
244 return iter->win->block[iter->block].bdesc;
245}
246
247static void msc_iter_init(struct msc_iter *iter)
248{
249 memset(iter, 0, sizeof(*iter));
250 iter->start_block = -1;
251 iter->block = -1;
252}
253
254static struct msc_iter *msc_iter_install(struct msc *msc)
255{
256 struct msc_iter *iter;
257
258 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
259 if (!iter)
260 return NULL;
261
262 msc_iter_init(iter);
263 iter->msc = msc;
264
265 mutex_lock(&msc->iter_mutex);
266 list_add_tail(&iter->entry, &msc->iter_list);
267 mutex_unlock(&msc->iter_mutex);
268
269 return iter;
270}
271
272static void msc_iter_remove(struct msc_iter *iter, struct msc *msc)
273{
274 mutex_lock(&msc->iter_mutex);
275 list_del(&iter->entry);
276 mutex_unlock(&msc->iter_mutex);
277
278 kfree(iter);
279}
280
281static void msc_iter_block_start(struct msc_iter *iter)
282{
283 if (iter->start_block != -1)
284 return;
285
286 iter->start_block = msc_win_oldest_block(iter->win);
287 iter->block = iter->start_block;
288 iter->wrap_count = 0;
289
290 /*
291 * start with the block with oldest data; if data has wrapped
292 * in this window, it should be in this block
293 */
294 if (msc_block_wrapped(msc_iter_bdesc(iter)))
295 iter->wrap_count = 2;
296
297}
298
299static int msc_iter_win_start(struct msc_iter *iter, struct msc *msc)
300{
301 /* already started, nothing to do */
302 if (iter->start_win)
303 return 0;
304
305 iter->start_win = msc_oldest_window(msc);
306 if (!iter->start_win)
307 return -EINVAL;
308
309 iter->win = iter->start_win;
310 iter->start_block = -1;
311
312 msc_iter_block_start(iter);
313
314 return 0;
315}
316
317static int msc_iter_win_advance(struct msc_iter *iter)
318{
319 iter->win = msc_next_window(iter->win);
320 iter->start_block = -1;
321
322 if (iter->win == iter->start_win) {
323 iter->eof++;
324 return 1;
325 }
326
327 msc_iter_block_start(iter);
328
329 return 0;
330}
331
332static int msc_iter_block_advance(struct msc_iter *iter)
333{
334 iter->block_off = 0;
335
336 /* wrapping */
337 if (iter->wrap_count && iter->block == iter->start_block) {
338 iter->wrap_count--;
339 if (!iter->wrap_count)
340 /* copied newest data from the wrapped block */
341 return msc_iter_win_advance(iter);
342 }
343
344 /* no wrapping, check for last written block */
345 if (!iter->wrap_count && msc_block_last_written(msc_iter_bdesc(iter)))
346 /* copied newest data for the window */
347 return msc_iter_win_advance(iter);
348
349 /* block advance */
350 if (++iter->block == iter->win->nr_blocks)
351 iter->block = 0;
352
353 /* no wrapping, sanity check in case there is no last written block */
354 if (!iter->wrap_count && iter->block == iter->start_block)
355 return msc_iter_win_advance(iter);
356
357 return 0;
358}
359
360/**
361 * msc_buffer_iterate() - go through multiblock buffer's data
362 * @iter: iterator structure
363 * @size: amount of data to scan
364 * @data: callback's private data
365 * @fn: iterator callback
366 *
367 * This will start at the window which will be written to next (containing
368 * the oldest data) and work its way to the current window, calling @fn
369 * for each chunk of data as it goes.
370 *
371 * Caller should have msc::user_count reference to make sure the buffer
372 * doesn't disappear from under us.
373 *
374 * Return: amount of data actually scanned.
375 */
376static ssize_t
377msc_buffer_iterate(struct msc_iter *iter, size_t size, void *data,
378 unsigned long (*fn)(void *, void *, size_t))
379{
380 struct msc *msc = iter->msc;
381 size_t len = size;
382 unsigned int advance;
383
384 if (iter->eof)
385 return 0;
386
387 /* start with the oldest window */
388 if (msc_iter_win_start(iter, msc))
389 return 0;
390
391 do {
392 unsigned long data_bytes = msc_data_sz(msc_iter_bdesc(iter));
393 void *src = (void *)msc_iter_bdesc(iter) + MSC_BDESC;
394 size_t tocopy = data_bytes, copied = 0;
395 size_t remaining = 0;
396
397 advance = 1;
398
399 /*
400 * If block wrapping happened, we need to visit the last block
401 * twice, because it contains both the oldest and the newest
402 * data in this window.
403 *
404 * First time (wrap_count==2), in the very beginning, to collect
405 * the oldest data, which is in the range
406 * (data_bytes..DATA_IN_PAGE).
407 *
408 * Second time (wrap_count==1), it's just like any other block,
409 * containing data in the range of [MSC_BDESC..data_bytes].
410 */
411 if (iter->block == iter->start_block && iter->wrap_count == 2) {
412 tocopy = DATA_IN_PAGE - data_bytes;
413 src += data_bytes;
414 }
415
416 if (!tocopy)
417 goto next_block;
418
419 tocopy -= iter->block_off;
420 src += iter->block_off;
421
422 if (len < tocopy) {
423 tocopy = len;
424 advance = 0;
425 }
426
427 remaining = fn(data, src, tocopy);
428
429 if (remaining)
430 advance = 0;
431
432 copied = tocopy - remaining;
433 len -= copied;
434 iter->block_off += copied;
435 iter->offset += copied;
436
437 if (!advance)
438 break;
439
440next_block:
441 if (msc_iter_block_advance(iter))
442 break;
443
444 } while (len);
445
446 return size - len;
447}
448
449/**
450 * msc_buffer_clear_hw_header() - clear hw header for multiblock
451 * @msc: MSC device
452 */
453static void msc_buffer_clear_hw_header(struct msc *msc)
454{
455 struct msc_window *win;
456
457 mutex_lock(&msc->buf_mutex);
458 list_for_each_entry(win, &msc->win_list, entry) {
459 unsigned int blk;
460 size_t hw_sz = sizeof(struct msc_block_desc) -
461 offsetof(struct msc_block_desc, hw_tag);
462
463 for (blk = 0; blk < win->nr_blocks; blk++) {
464 struct msc_block_desc *bdesc = win->block[blk].bdesc;
465
466 memset(&bdesc->hw_tag, 0, hw_sz);
467 }
468 }
469 mutex_unlock(&msc->buf_mutex);
470}
471
472/**
473 * msc_configure() - set up MSC hardware
474 * @msc: the MSC device to configure
475 *
476 * Program storage mode, wrapping, burst length and trace buffer address
477 * into a given MSC. If msc::enabled is set, enable the trace, too.
478 */
479static int msc_configure(struct msc *msc)
480{
481 u32 reg;
482
483 if (msc->mode > MSC_MODE_MULTI)
484 return -ENOTSUPP;
485
486 if (msc->mode == MSC_MODE_MULTI)
487 msc_buffer_clear_hw_header(msc);
488
489 reg = msc->base_addr >> PAGE_SHIFT;
490 iowrite32(reg, msc->reg_base + REG_MSU_MSC0BAR);
491
492 if (msc->mode == MSC_MODE_SINGLE) {
493 reg = msc->nr_pages;
494 iowrite32(reg, msc->reg_base + REG_MSU_MSC0SIZE);
495 }
496
497 reg = ioread32(msc->reg_base + REG_MSU_MSC0CTL);
498 reg &= ~(MSC_MODE | MSC_WRAPEN | MSC_EN | MSC_RD_HDR_OVRD);
499
500 reg |= msc->mode << __ffs(MSC_MODE);
501 reg |= msc->burst_len << __ffs(MSC_LEN);
502 /*if (msc->mode == MSC_MODE_MULTI)
503 reg |= MSC_RD_HDR_OVRD; */
504 if (msc->wrap)
505 reg |= MSC_WRAPEN;
506 if (msc->enabled)
507 reg |= MSC_EN;
508
509 iowrite32(reg, msc->reg_base + REG_MSU_MSC0CTL);
510
511 if (msc->enabled) {
512 msc->thdev->output.multiblock = msc->mode == MSC_MODE_MULTI;
513 intel_th_trace_enable(msc->thdev);
514 }
515
516 return 0;
517}
518
519/**
520 * msc_disable() - disable MSC hardware
521 * @msc: MSC device to disable
522 *
523 * If @msc is enabled, disable tracing on the switch and then disable MSC
524 * storage.
525 */
526static void msc_disable(struct msc *msc)
527{
528 unsigned long count;
529 u32 reg;
530
531 if (!msc->enabled)
532 return;
533
534 intel_th_trace_disable(msc->thdev);
535
536 for (reg = 0, count = MSC_PLE_WAITLOOP_DEPTH;
537 count && !(reg & MSCSTS_PLE); count--) {
538 reg = ioread32(msc->reg_base + REG_MSU_MSC0STS);
539 cpu_relax();
540 }
541
542 if (!count)
543 dev_dbg(msc_dev(msc), "timeout waiting for MSC0 PLE\n");
544
545 if (msc->mode == MSC_MODE_SINGLE) {
546 msc->single_wrap = !!(reg & MSCSTS_WRAPSTAT);
547
548 reg = ioread32(msc->reg_base + REG_MSU_MSC0MWP);
549 msc->single_sz = reg & ((msc->nr_pages << PAGE_SHIFT) - 1);
550 dev_dbg(msc_dev(msc), "MSCnMWP: %08x/%08lx, wrap: %d\n",
551 reg, msc->single_sz, msc->single_wrap);
552 }
553
554 reg = ioread32(msc->reg_base + REG_MSU_MSC0CTL);
555 reg &= ~MSC_EN;
556 iowrite32(reg, msc->reg_base + REG_MSU_MSC0CTL);
557 msc->enabled = 0;
558
559 iowrite32(0, msc->reg_base + REG_MSU_MSC0BAR);
560 iowrite32(0, msc->reg_base + REG_MSU_MSC0SIZE);
561
562 dev_dbg(msc_dev(msc), "MSCnNWSA: %08x\n",
563 ioread32(msc->reg_base + REG_MSU_MSC0NWSA));
564
565 reg = ioread32(msc->reg_base + REG_MSU_MSC0STS);
566 dev_dbg(msc_dev(msc), "MSCnSTS: %08x\n", reg);
567}
568
569static int intel_th_msc_activate(struct intel_th_device *thdev)
570{
571 struct msc *msc = dev_get_drvdata(&thdev->dev);
572 int ret = 0;
573
574 if (!atomic_inc_unless_negative(&msc->user_count))
575 return -ENODEV;
576
577 mutex_lock(&msc->iter_mutex);
578 if (!list_empty(&msc->iter_list))
579 ret = -EBUSY;
580 mutex_unlock(&msc->iter_mutex);
581
582 if (ret) {
583 atomic_dec(&msc->user_count);
584 return ret;
585 }
586
587 msc->enabled = 1;
588
589 return msc_configure(msc);
590}
591
592static void intel_th_msc_deactivate(struct intel_th_device *thdev)
593{
594 struct msc *msc = dev_get_drvdata(&thdev->dev);
595
596 msc_disable(msc);
597
598 atomic_dec(&msc->user_count);
599}
600
601/**
602 * msc_buffer_contig_alloc() - allocate a contiguous buffer for SINGLE mode
603 * @msc: MSC device
604 * @size: allocation size in bytes
605 *
606 * This modifies msc::base, which requires msc::buf_mutex to serialize, so the
607 * caller is expected to hold it.
608 *
609 * Return: 0 on success, -errno otherwise.
610 */
611static int msc_buffer_contig_alloc(struct msc *msc, unsigned long size)
612{
613 unsigned int order = get_order(size);
614 struct page *page;
615
616 if (!size)
617 return 0;
618
619 page = alloc_pages(GFP_KERNEL | __GFP_ZERO, order);
620 if (!page)
621 return -ENOMEM;
622
623 split_page(page, order);
624 msc->nr_pages = size >> PAGE_SHIFT;
625 msc->base = page_address(page);
626 msc->base_addr = page_to_phys(page);
627
628 return 0;
629}
630
631/**
632 * msc_buffer_contig_free() - free a contiguous buffer
633 * @msc: MSC configured in SINGLE mode
634 */
635static void msc_buffer_contig_free(struct msc *msc)
636{
637 unsigned long off;
638
639 for (off = 0; off < msc->nr_pages << PAGE_SHIFT; off += PAGE_SIZE) {
640 struct page *page = virt_to_page(msc->base + off);
641
642 page->mapping = NULL;
643 __free_page(page);
644 }
645
646 msc->nr_pages = 0;
647}
648
649/**
650 * msc_buffer_contig_get_page() - find a page at a given offset
651 * @msc: MSC configured in SINGLE mode
652 * @pgoff: page offset
653 *
654 * Return: page, if @pgoff is within the range, NULL otherwise.
655 */
656static struct page *msc_buffer_contig_get_page(struct msc *msc,
657 unsigned long pgoff)
658{
659 if (pgoff >= msc->nr_pages)
660 return NULL;
661
662 return virt_to_page(msc->base + (pgoff << PAGE_SHIFT));
663}
664
665/**
666 * msc_buffer_win_alloc() - alloc a window for a multiblock mode
667 * @msc: MSC device
668 * @nr_blocks: number of pages in this window
669 *
670 * This modifies msc::win_list and msc::base, which requires msc::buf_mutex
671 * to serialize, so the caller is expected to hold it.
672 *
673 * Return: 0 on success, -errno otherwise.
674 */
675static int msc_buffer_win_alloc(struct msc *msc, unsigned int nr_blocks)
676{
677 struct msc_window *win;
678 unsigned long size = PAGE_SIZE;
679 int i, ret = -ENOMEM;
680
681 if (!nr_blocks)
682 return 0;
683
684 win = kzalloc(offsetof(struct msc_window, block[nr_blocks]),
685 GFP_KERNEL);
686 if (!win)
687 return -ENOMEM;
688
689 if (!list_empty(&msc->win_list)) {
690 struct msc_window *prev = list_entry(msc->win_list.prev,
691 struct msc_window, entry);
692
693 win->pgoff = prev->pgoff + prev->nr_blocks;
694 }
695
696 for (i = 0; i < nr_blocks; i++) {
697 win->block[i].bdesc = dma_alloc_coherent(msc_dev(msc), size,
698 &win->block[i].addr,
699 GFP_KERNEL);
700
701#ifdef CONFIG_X86
702 /* Set the page as uncached */
703 set_memory_uc((unsigned long)win->block[i].bdesc, 1);
704#endif
705
706 if (!win->block[i].bdesc)
707 goto err_nomem;
708 }
709
710 win->msc = msc;
711 win->nr_blocks = nr_blocks;
712
713 if (list_empty(&msc->win_list)) {
714 msc->base = win->block[0].bdesc;
715 msc->base_addr = win->block[0].addr;
716 }
717
718 list_add_tail(&win->entry, &msc->win_list);
719 msc->nr_pages += nr_blocks;
720
721 return 0;
722
723err_nomem:
724 for (i--; i >= 0; i--) {
725#ifdef CONFIG_X86
726 /* Reset the page to write-back before releasing */
727 set_memory_wb((unsigned long)win->block[i].bdesc, 1);
728#endif
729 dma_free_coherent(msc_dev(msc), size, win->block[i].bdesc,
730 win->block[i].addr);
731 }
732 kfree(win);
733
734 return ret;
735}
736
737/**
738 * msc_buffer_win_free() - free a window from MSC's window list
739 * @msc: MSC device
740 * @win: window to free
741 *
742 * This modifies msc::win_list and msc::base, which requires msc::buf_mutex
743 * to serialize, so the caller is expected to hold it.
744 */
745static void msc_buffer_win_free(struct msc *msc, struct msc_window *win)
746{
747 int i;
748
749 msc->nr_pages -= win->nr_blocks;
750
751 list_del(&win->entry);
752 if (list_empty(&msc->win_list)) {
753 msc->base = NULL;
754 msc->base_addr = 0;
755 }
756
757 for (i = 0; i < win->nr_blocks; i++) {
758 struct page *page = virt_to_page(win->block[i].bdesc);
759
760 page->mapping = NULL;
761#ifdef CONFIG_X86
762 /* Reset the page to write-back before releasing */
763 set_memory_wb((unsigned long)win->block[i].bdesc, 1);
764#endif
765 dma_free_coherent(msc_dev(win->msc), PAGE_SIZE,
766 win->block[i].bdesc, win->block[i].addr);
767 }
768
769 kfree(win);
770}
771
772/**
773 * msc_buffer_relink() - set up block descriptors for multiblock mode
774 * @msc: MSC device
775 *
776 * This traverses msc::win_list, which requires msc::buf_mutex to serialize,
777 * so the caller is expected to hold it.
778 */
779static void msc_buffer_relink(struct msc *msc)
780{
781 struct msc_window *win, *next_win;
782
783 /* call with msc::mutex locked */
784 list_for_each_entry(win, &msc->win_list, entry) {
785 unsigned int blk;
786 u32 sw_tag = 0;
787
788 /*
789 * Last window's next_win should point to the first window
790 * and MSC_SW_TAG_LASTWIN should be set.
791 */
792 if (msc_is_last_win(win)) {
793 sw_tag |= MSC_SW_TAG_LASTWIN;
794 next_win = list_entry(msc->win_list.next,
795 struct msc_window, entry);
796 } else {
797 next_win = list_entry(win->entry.next,
798 struct msc_window, entry);
799 }
800
801 for (blk = 0; blk < win->nr_blocks; blk++) {
802 struct msc_block_desc *bdesc = win->block[blk].bdesc;
803
804 memset(bdesc, 0, sizeof(*bdesc));
805
806 bdesc->next_win = next_win->block[0].addr >> PAGE_SHIFT;
807
808 /*
809 * Similarly to last window, last block should point
810 * to the first one.
811 */
812 if (blk == win->nr_blocks - 1) {
813 sw_tag |= MSC_SW_TAG_LASTBLK;
814 bdesc->next_blk =
815 win->block[0].addr >> PAGE_SHIFT;
816 } else {
817 bdesc->next_blk =
818 win->block[blk + 1].addr >> PAGE_SHIFT;
819 }
820
821 bdesc->sw_tag = sw_tag;
822 bdesc->block_sz = PAGE_SIZE / 64;
823 }
824 }
825
826 /*
827 * Make the above writes globally visible before tracing is
828 * enabled to make sure hardware sees them coherently.
829 */
830 wmb();
831}
832
833static void msc_buffer_multi_free(struct msc *msc)
834{
835 struct msc_window *win, *iter;
836
837 list_for_each_entry_safe(win, iter, &msc->win_list, entry)
838 msc_buffer_win_free(msc, win);
839}
840
841static int msc_buffer_multi_alloc(struct msc *msc, unsigned long *nr_pages,
842 unsigned int nr_wins)
843{
844 int ret, i;
845
846 for (i = 0; i < nr_wins; i++) {
847 ret = msc_buffer_win_alloc(msc, nr_pages[i]);
848 if (ret) {
849 msc_buffer_multi_free(msc);
850 return ret;
851 }
852 }
853
854 msc_buffer_relink(msc);
855
856 return 0;
857}
858
859/**
860 * msc_buffer_free() - free buffers for MSC
861 * @msc: MSC device
862 *
863 * Free MSC's storage buffers.
864 *
865 * This modifies msc::win_list and msc::base, which requires msc::buf_mutex to
866 * serialize, so the caller is expected to hold it.
867 */
868static void msc_buffer_free(struct msc *msc)
869{
870 if (msc->mode == MSC_MODE_SINGLE)
871 msc_buffer_contig_free(msc);
872 else if (msc->mode == MSC_MODE_MULTI)
873 msc_buffer_multi_free(msc);
874}
875
876/**
877 * msc_buffer_alloc() - allocate a buffer for MSC
878 * @msc: MSC device
879 * @size: allocation size in bytes
880 *
881 * Allocate a storage buffer for MSC, depending on the msc::mode, it will be
882 * either done via msc_buffer_contig_alloc() for SINGLE operation mode or
883 * msc_buffer_win_alloc() for multiblock operation. The latter allocates one
884 * window per invocation, so in multiblock mode this can be called multiple
885 * times for the same MSC to allocate multiple windows.
886 *
887 * This modifies msc::win_list and msc::base, which requires msc::buf_mutex
888 * to serialize, so the caller is expected to hold it.
889 *
890 * Return: 0 on success, -errno otherwise.
891 */
892static int msc_buffer_alloc(struct msc *msc, unsigned long *nr_pages,
893 unsigned int nr_wins)
894{
895 int ret;
896
897 /* -1: buffer not allocated */
898 if (atomic_read(&msc->user_count) != -1)
899 return -EBUSY;
900
901 if (msc->mode == MSC_MODE_SINGLE) {
902 if (nr_wins != 1)
903 return -EINVAL;
904
905 ret = msc_buffer_contig_alloc(msc, nr_pages[0] << PAGE_SHIFT);
906 } else if (msc->mode == MSC_MODE_MULTI) {
907 ret = msc_buffer_multi_alloc(msc, nr_pages, nr_wins);
908 } else {
909 ret = -ENOTSUPP;
910 }
911
912 if (!ret) {
913 /* allocation should be visible before the counter goes to 0 */
914 smp_mb__before_atomic();
915
916 if (WARN_ON_ONCE(atomic_cmpxchg(&msc->user_count, -1, 0) != -1))
917 return -EINVAL;
918 }
919
920 return ret;
921}
922
923/**
924 * msc_buffer_unlocked_free_unless_used() - free a buffer unless it's in use
925 * @msc: MSC device
926 *
927 * This will free MSC buffer unless it is in use or there is no allocated
928 * buffer.
929 * Caller needs to hold msc::buf_mutex.
930 *
931 * Return: 0 on successful deallocation or if there was no buffer to
932 * deallocate, -EBUSY if there are active users.
933 */
934static int msc_buffer_unlocked_free_unless_used(struct msc *msc)
935{
936 int count, ret = 0;
937
938 count = atomic_cmpxchg(&msc->user_count, 0, -1);
939
940 /* > 0: buffer is allocated and has users */
941 if (count > 0)
942 ret = -EBUSY;
943 /* 0: buffer is allocated, no users */
944 else if (!count)
945 msc_buffer_free(msc);
946 /* < 0: no buffer, nothing to do */
947
948 return ret;
949}
950
951/**
952 * msc_buffer_free_unless_used() - free a buffer unless it's in use
953 * @msc: MSC device
954 *
955 * This is a locked version of msc_buffer_unlocked_free_unless_used().
956 */
957static int msc_buffer_free_unless_used(struct msc *msc)
958{
959 int ret;
960
961 mutex_lock(&msc->buf_mutex);
962 ret = msc_buffer_unlocked_free_unless_used(msc);
963 mutex_unlock(&msc->buf_mutex);
964
965 return ret;
966}
967
968/**
969 * msc_buffer_get_page() - get MSC buffer page at a given offset
970 * @msc: MSC device
971 * @pgoff: page offset into the storage buffer
972 *
973 * This traverses msc::win_list, so holding msc::buf_mutex is expected from
974 * the caller.
975 *
976 * Return: page if @pgoff corresponds to a valid buffer page or NULL.
977 */
978static struct page *msc_buffer_get_page(struct msc *msc, unsigned long pgoff)
979{
980 struct msc_window *win;
981
982 if (msc->mode == MSC_MODE_SINGLE)
983 return msc_buffer_contig_get_page(msc, pgoff);
984
985 list_for_each_entry(win, &msc->win_list, entry)
986 if (pgoff >= win->pgoff && pgoff < win->pgoff + win->nr_blocks)
987 goto found;
988
989 return NULL;
990
991found:
992 pgoff -= win->pgoff;
993 return virt_to_page(win->block[pgoff].bdesc);
994}
995
996/**
997 * struct msc_win_to_user_struct - data for copy_to_user() callback
998 * @buf: userspace buffer to copy data to
999 * @offset: running offset
1000 */
1001struct msc_win_to_user_struct {
1002 char __user *buf;
1003 unsigned long offset;
1004};
1005
1006/**
1007 * msc_win_to_user() - iterator for msc_buffer_iterate() to copy data to user
1008 * @data: callback's private data
1009 * @src: source buffer
1010 * @len: amount of data to copy from the source buffer
1011 */
1012static unsigned long msc_win_to_user(void *data, void *src, size_t len)
1013{
1014 struct msc_win_to_user_struct *u = data;
1015 unsigned long ret;
1016
1017 ret = copy_to_user(u->buf + u->offset, src, len);
1018 u->offset += len - ret;
1019
1020 return ret;
1021}
1022
1023
1024/*
1025 * file operations' callbacks
1026 */
1027
1028static int intel_th_msc_open(struct inode *inode, struct file *file)
1029{
1030 struct intel_th_device *thdev = file->private_data;
1031 struct msc *msc = dev_get_drvdata(&thdev->dev);
1032 struct msc_iter *iter;
1033
1034 if (!capable(CAP_SYS_RAWIO))
1035 return -EPERM;
1036
1037 iter = msc_iter_install(msc);
1038 if (!iter)
1039 return -ENOMEM;
1040
1041 file->private_data = iter;
1042
1043 return nonseekable_open(inode, file);
1044}
1045
1046static int intel_th_msc_release(struct inode *inode, struct file *file)
1047{
1048 struct msc_iter *iter = file->private_data;
1049 struct msc *msc = iter->msc;
1050
1051 msc_iter_remove(iter, msc);
1052
1053 return 0;
1054}
1055
1056static ssize_t
1057msc_single_to_user(struct msc *msc, char __user *buf, loff_t off, size_t len)
1058{
1059 unsigned long size = msc->nr_pages << PAGE_SHIFT, rem = len;
1060 unsigned long start = off, tocopy = 0;
1061
1062 if (msc->single_wrap) {
1063 start += msc->single_sz;
1064 if (start < size) {
1065 tocopy = min(rem, size - start);
1066 if (copy_to_user(buf, msc->base + start, tocopy))
1067 return -EFAULT;
1068
1069 buf += tocopy;
1070 rem -= tocopy;
1071 start += tocopy;
1072 }
1073
1074 start &= size - 1;
1075 if (rem) {
1076 tocopy = min(rem, msc->single_sz - start);
1077 if (copy_to_user(buf, msc->base + start, tocopy))
1078 return -EFAULT;
1079
1080 rem -= tocopy;
1081 }
1082
1083 return len - rem;
1084 }
1085
1086 if (copy_to_user(buf, msc->base + start, rem))
1087 return -EFAULT;
1088
1089 return len;
1090}
1091
1092static ssize_t intel_th_msc_read(struct file *file, char __user *buf,
1093 size_t len, loff_t *ppos)
1094{
1095 struct msc_iter *iter = file->private_data;
1096 struct msc *msc = iter->msc;
1097 size_t size;
1098 loff_t off = *ppos;
1099 ssize_t ret = 0;
1100
1101 if (!atomic_inc_unless_negative(&msc->user_count))
1102 return 0;
1103
1104 if (msc->enabled) {
1105 ret = -EBUSY;
1106 goto put_count;
1107 }
1108
1109 if (msc->mode == MSC_MODE_SINGLE && !msc->single_wrap)
1110 size = msc->single_sz;
1111 else
1112 size = msc->nr_pages << PAGE_SHIFT;
1113
1114 if (!size)
1115 goto put_count;
1116
1117 if (off >= size)
1118 goto put_count;
1119
1120 if (off + len >= size)
1121 len = size - off;
1122
1123 if (msc->mode == MSC_MODE_SINGLE) {
1124 ret = msc_single_to_user(msc, buf, off, len);
1125 if (ret >= 0)
1126 *ppos += ret;
1127 } else if (msc->mode == MSC_MODE_MULTI) {
1128 struct msc_win_to_user_struct u = {
1129 .buf = buf,
1130 .offset = 0,
1131 };
1132
1133 ret = msc_buffer_iterate(iter, len, &u, msc_win_to_user);
1134 if (ret >= 0)
1135 *ppos = iter->offset;
1136 } else {
1137 ret = -ENOTSUPP;
1138 }
1139
1140put_count:
1141 atomic_dec(&msc->user_count);
1142
1143 return ret;
1144}
1145
1146/*
1147 * vm operations callbacks (vm_ops)
1148 */
1149
1150static void msc_mmap_open(struct vm_area_struct *vma)
1151{
1152 struct msc_iter *iter = vma->vm_file->private_data;
1153 struct msc *msc = iter->msc;
1154
1155 atomic_inc(&msc->mmap_count);
1156}
1157
1158static void msc_mmap_close(struct vm_area_struct *vma)
1159{
1160 struct msc_iter *iter = vma->vm_file->private_data;
1161 struct msc *msc = iter->msc;
1162 unsigned long pg;
1163
1164 if (!atomic_dec_and_mutex_lock(&msc->mmap_count, &msc->buf_mutex))
1165 return;
1166
1167 /* drop page _counts */
1168 for (pg = 0; pg < msc->nr_pages; pg++) {
1169 struct page *page = msc_buffer_get_page(msc, pg);
1170
1171 if (WARN_ON_ONCE(!page))
1172 continue;
1173
1174 if (page->mapping)
1175 page->mapping = NULL;
1176 }
1177
1178 /* last mapping -- drop user_count */
1179 atomic_dec(&msc->user_count);
1180 mutex_unlock(&msc->buf_mutex);
1181}
1182
1183static int msc_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
1184{
1185 struct msc_iter *iter = vma->vm_file->private_data;
1186 struct msc *msc = iter->msc;
1187
1188 vmf->page = msc_buffer_get_page(msc, vmf->pgoff);
1189 if (!vmf->page)
1190 return VM_FAULT_SIGBUS;
1191
1192 get_page(vmf->page);
1193 vmf->page->mapping = vma->vm_file->f_mapping;
1194 vmf->page->index = vmf->pgoff;
1195
1196 return 0;
1197}
1198
1199static const struct vm_operations_struct msc_mmap_ops = {
1200 .open = msc_mmap_open,
1201 .close = msc_mmap_close,
1202 .fault = msc_mmap_fault,
1203};
1204
1205static int intel_th_msc_mmap(struct file *file, struct vm_area_struct *vma)
1206{
1207 unsigned long size = vma->vm_end - vma->vm_start;
1208 struct msc_iter *iter = vma->vm_file->private_data;
1209 struct msc *msc = iter->msc;
1210 int ret = -EINVAL;
1211
1212 if (!size || offset_in_page(size))
1213 return -EINVAL;
1214
1215 if (vma->vm_pgoff)
1216 return -EINVAL;
1217
1218 /* grab user_count once per mmap; drop in msc_mmap_close() */
1219 if (!atomic_inc_unless_negative(&msc->user_count))
1220 return -EINVAL;
1221
1222 if (msc->mode != MSC_MODE_SINGLE &&
1223 msc->mode != MSC_MODE_MULTI)
1224 goto out;
1225
1226 if (size >> PAGE_SHIFT != msc->nr_pages)
1227 goto out;
1228
1229 atomic_set(&msc->mmap_count, 1);
1230 ret = 0;
1231
1232out:
1233 if (ret)
1234 atomic_dec(&msc->user_count);
1235
1236 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
1237 vma->vm_flags |= VM_DONTEXPAND | VM_DONTCOPY;
1238 vma->vm_ops = &msc_mmap_ops;
1239 return ret;
1240}
1241
1242static const struct file_operations intel_th_msc_fops = {
1243 .open = intel_th_msc_open,
1244 .release = intel_th_msc_release,
1245 .read = intel_th_msc_read,
1246 .mmap = intel_th_msc_mmap,
1247 .llseek = no_llseek,
1248};
1249
1250static int intel_th_msc_init(struct msc *msc)
1251{
1252 atomic_set(&msc->user_count, -1);
1253
1254 msc->mode = MSC_MODE_MULTI;
1255 mutex_init(&msc->buf_mutex);
1256 INIT_LIST_HEAD(&msc->win_list);
1257
1258 mutex_init(&msc->iter_mutex);
1259 INIT_LIST_HEAD(&msc->iter_list);
1260
1261 msc->burst_len =
1262 (ioread32(msc->reg_base + REG_MSU_MSC0CTL) & MSC_LEN) >>
1263 __ffs(MSC_LEN);
1264
1265 return 0;
1266}
1267
1268static const char * const msc_mode[] = {
1269 [MSC_MODE_SINGLE] = "single",
1270 [MSC_MODE_MULTI] = "multi",
1271 [MSC_MODE_EXI] = "ExI",
1272 [MSC_MODE_DEBUG] = "debug",
1273};
1274
1275static ssize_t
1276wrap_show(struct device *dev, struct device_attribute *attr, char *buf)
1277{
1278 struct msc *msc = dev_get_drvdata(dev);
1279
1280 return scnprintf(buf, PAGE_SIZE, "%d\n", msc->wrap);
1281}
1282
1283static ssize_t
1284wrap_store(struct device *dev, struct device_attribute *attr, const char *buf,
1285 size_t size)
1286{
1287 struct msc *msc = dev_get_drvdata(dev);
1288 unsigned long val;
1289 int ret;
1290
1291 ret = kstrtoul(buf, 10, &val);
1292 if (ret)
1293 return ret;
1294
1295 msc->wrap = !!val;
1296
1297 return size;
1298}
1299
1300static DEVICE_ATTR_RW(wrap);
1301
1302static ssize_t
1303mode_show(struct device *dev, struct device_attribute *attr, char *buf)
1304{
1305 struct msc *msc = dev_get_drvdata(dev);
1306
1307 return scnprintf(buf, PAGE_SIZE, "%s\n", msc_mode[msc->mode]);
1308}
1309
1310static ssize_t
1311mode_store(struct device *dev, struct device_attribute *attr, const char *buf,
1312 size_t size)
1313{
1314 struct msc *msc = dev_get_drvdata(dev);
1315 size_t len = size;
1316 char *cp;
1317 int i, ret;
1318
1319 if (!capable(CAP_SYS_RAWIO))
1320 return -EPERM;
1321
1322 cp = memchr(buf, '\n', len);
1323 if (cp)
1324 len = cp - buf;
1325
1326 for (i = 0; i < ARRAY_SIZE(msc_mode); i++)
1327 if (!strncmp(msc_mode[i], buf, len))
1328 goto found;
1329
1330 return -EINVAL;
1331
1332found:
1333 mutex_lock(&msc->buf_mutex);
1334 ret = msc_buffer_unlocked_free_unless_used(msc);
1335 if (!ret)
1336 msc->mode = i;
1337 mutex_unlock(&msc->buf_mutex);
1338
1339 return ret ? ret : size;
1340}
1341
1342static DEVICE_ATTR_RW(mode);
1343
1344static ssize_t
1345nr_pages_show(struct device *dev, struct device_attribute *attr, char *buf)
1346{
1347 struct msc *msc = dev_get_drvdata(dev);
1348 struct msc_window *win;
1349 size_t count = 0;
1350
1351 mutex_lock(&msc->buf_mutex);
1352
1353 if (msc->mode == MSC_MODE_SINGLE)
1354 count = scnprintf(buf, PAGE_SIZE, "%ld\n", msc->nr_pages);
1355 else if (msc->mode == MSC_MODE_MULTI) {
1356 list_for_each_entry(win, &msc->win_list, entry) {
1357 count += scnprintf(buf + count, PAGE_SIZE - count,
1358 "%d%c", win->nr_blocks,
1359 msc_is_last_win(win) ? '\n' : ',');
1360 }
1361 } else {
1362 count = scnprintf(buf, PAGE_SIZE, "unsupported\n");
1363 }
1364
1365 mutex_unlock(&msc->buf_mutex);
1366
1367 return count;
1368}
1369
1370static ssize_t
1371nr_pages_store(struct device *dev, struct device_attribute *attr,
1372 const char *buf, size_t size)
1373{
1374 struct msc *msc = dev_get_drvdata(dev);
1375 unsigned long val, *win = NULL, *rewin;
1376 size_t len = size;
1377 const char *p = buf;
1378 char *end, *s;
1379 int ret, nr_wins = 0;
1380
1381 if (!capable(CAP_SYS_RAWIO))
1382 return -EPERM;
1383
1384 ret = msc_buffer_free_unless_used(msc);
1385 if (ret)
1386 return ret;
1387
1388 /* scan the comma-separated list of allocation sizes */
1389 end = memchr(buf, '\n', len);
1390 if (end)
1391 len = end - buf;
1392
1393 do {
1394 end = memchr(p, ',', len);
1395 s = kstrndup(p, end ? end - p : len, GFP_KERNEL);
1396 ret = kstrtoul(s, 10, &val);
1397 kfree(s);
1398
1399 if (ret || !val)
1400 goto free_win;
1401
1402 if (nr_wins && msc->mode == MSC_MODE_SINGLE) {
1403 ret = -EINVAL;
1404 goto free_win;
1405 }
1406
1407 nr_wins++;
1408 rewin = krealloc(win, sizeof(*win) * nr_wins, GFP_KERNEL);
1409 if (!rewin) {
1410 kfree(win);
1411 return -ENOMEM;
1412 }
1413
1414 win = rewin;
1415 win[nr_wins - 1] = val;
1416
1417 if (!end)
1418 break;
1419
1420 len -= end - p;
1421 p = end + 1;
1422 } while (len);
1423
1424 mutex_lock(&msc->buf_mutex);
1425 ret = msc_buffer_alloc(msc, win, nr_wins);
1426 mutex_unlock(&msc->buf_mutex);
1427
1428free_win:
1429 kfree(win);
1430
1431 return ret ? ret : size;
1432}
1433
1434static DEVICE_ATTR_RW(nr_pages);
1435
1436static struct attribute *msc_output_attrs[] = {
1437 &dev_attr_wrap.attr,
1438 &dev_attr_mode.attr,
1439 &dev_attr_nr_pages.attr,
1440 NULL,
1441};
1442
1443static struct attribute_group msc_output_group = {
1444 .attrs = msc_output_attrs,
1445};
1446
1447static int intel_th_msc_probe(struct intel_th_device *thdev)
1448{
1449 struct device *dev = &thdev->dev;
1450 struct resource *res;
1451 struct msc *msc;
1452 void __iomem *base;
1453 int err;
1454
1455 res = intel_th_device_get_resource(thdev, IORESOURCE_MEM, 0);
1456 if (!res)
1457 return -ENODEV;
1458
1459 base = devm_ioremap(dev, res->start, resource_size(res));
1460 if (!base)
1461 return -ENOMEM;
1462
1463 msc = devm_kzalloc(dev, sizeof(*msc), GFP_KERNEL);
1464 if (!msc)
1465 return -ENOMEM;
1466
1467 msc->index = thdev->id;
1468
1469 msc->thdev = thdev;
1470 msc->reg_base = base + msc->index * 0x100;
1471
1472 err = intel_th_msc_init(msc);
1473 if (err)
1474 return err;
1475
1476 err = sysfs_create_group(&dev->kobj, &msc_output_group);
1477 if (err)
1478 return err;
1479
1480 dev_set_drvdata(dev, msc);
1481
1482 return 0;
1483}
1484
1485static void intel_th_msc_remove(struct intel_th_device *thdev)
1486{
1487 sysfs_remove_group(&thdev->dev.kobj, &msc_output_group);
1488}
1489
1490static struct intel_th_driver intel_th_msc_driver = {
1491 .probe = intel_th_msc_probe,
1492 .remove = intel_th_msc_remove,
1493 .activate = intel_th_msc_activate,
1494 .deactivate = intel_th_msc_deactivate,
1495 .fops = &intel_th_msc_fops,
1496 .driver = {
1497 .name = "msc",
1498 .owner = THIS_MODULE,
1499 },
1500};
1501
1502module_driver(intel_th_msc_driver,
1503 intel_th_driver_register,
1504 intel_th_driver_unregister);
1505
1506MODULE_LICENSE("GPL v2");
1507MODULE_DESCRIPTION("Intel(R) Trace Hub Memory Storage Unit driver");
1508MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@linux.intel.com>");
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Intel(R) Trace Hub Memory Storage Unit
4 *
5 * Copyright (C) 2014-2015 Intel Corporation.
6 */
7
8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
10#include <linux/types.h>
11#include <linux/module.h>
12#include <linux/device.h>
13#include <linux/uaccess.h>
14#include <linux/sizes.h>
15#include <linux/printk.h>
16#include <linux/slab.h>
17#include <linux/mm.h>
18#include <linux/fs.h>
19#include <linux/io.h>
20#include <linux/workqueue.h>
21#include <linux/dma-mapping.h>
22
23#ifdef CONFIG_X86
24#include <asm/set_memory.h>
25#endif
26
27#include <linux/intel_th.h>
28#include "intel_th.h"
29#include "msu.h"
30
31#define msc_dev(x) (&(x)->thdev->dev)
32
33/*
34 * Lockout state transitions:
35 * READY -> INUSE -+-> LOCKED -+-> READY -> etc.
36 * \-----------/
37 * WIN_READY: window can be used by HW
38 * WIN_INUSE: window is in use
39 * WIN_LOCKED: window is filled up and is being processed by the buffer
40 * handling code
41 *
42 * All state transitions happen automatically, except for the LOCKED->READY,
43 * which needs to be signalled by the buffer code by calling
44 * intel_th_msc_window_unlock().
45 *
46 * When the interrupt handler has to switch to the next window, it checks
47 * whether it's READY, and if it is, it performs the switch and tracing
48 * continues. If it's LOCKED, it stops the trace.
49 */
50enum lockout_state {
51 WIN_READY = 0,
52 WIN_INUSE,
53 WIN_LOCKED
54};
55
56/**
57 * struct msc_window - multiblock mode window descriptor
58 * @entry: window list linkage (msc::win_list)
59 * @pgoff: page offset into the buffer that this window starts at
60 * @lockout: lockout state, see comment below
61 * @lo_lock: lockout state serialization
62 * @nr_blocks: number of blocks (pages) in this window
63 * @nr_segs: number of segments in this window (<= @nr_blocks)
64 * @_sgt: array of block descriptors
65 * @sgt: array of block descriptors
66 */
67struct msc_window {
68 struct list_head entry;
69 unsigned long pgoff;
70 enum lockout_state lockout;
71 spinlock_t lo_lock;
72 unsigned int nr_blocks;
73 unsigned int nr_segs;
74 struct msc *msc;
75 struct sg_table _sgt;
76 struct sg_table *sgt;
77};
78
79/**
80 * struct msc_iter - iterator for msc buffer
81 * @entry: msc::iter_list linkage
82 * @msc: pointer to the MSC device
83 * @start_win: oldest window
84 * @win: current window
85 * @offset: current logical offset into the buffer
86 * @start_block: oldest block in the window
87 * @block: block number in the window
88 * @block_off: offset into current block
89 * @wrap_count: block wrapping handling
90 * @eof: end of buffer reached
91 */
92struct msc_iter {
93 struct list_head entry;
94 struct msc *msc;
95 struct msc_window *start_win;
96 struct msc_window *win;
97 unsigned long offset;
98 struct scatterlist *start_block;
99 struct scatterlist *block;
100 unsigned int block_off;
101 unsigned int wrap_count;
102 unsigned int eof;
103};
104
105/**
106 * struct msc - MSC device representation
107 * @reg_base: register window base address
108 * @thdev: intel_th_device pointer
109 * @mbuf: MSU buffer, if assigned
110 * @mbuf_priv MSU buffer's private data, if @mbuf
111 * @win_list: list of windows in multiblock mode
112 * @single_sgt: single mode buffer
113 * @cur_win: current window
114 * @nr_pages: total number of pages allocated for this buffer
115 * @single_sz: amount of data in single mode
116 * @single_wrap: single mode wrap occurred
117 * @base: buffer's base pointer
118 * @base_addr: buffer's base address
119 * @user_count: number of users of the buffer
120 * @mmap_count: number of mappings
121 * @buf_mutex: mutex to serialize access to buffer-related bits
122
123 * @enabled: MSC is enabled
124 * @wrap: wrapping is enabled
125 * @mode: MSC operating mode
126 * @burst_len: write burst length
127 * @index: number of this MSC in the MSU
128 */
129struct msc {
130 void __iomem *reg_base;
131 void __iomem *msu_base;
132 struct intel_th_device *thdev;
133
134 const struct msu_buffer *mbuf;
135 void *mbuf_priv;
136
137 struct work_struct work;
138 struct list_head win_list;
139 struct sg_table single_sgt;
140 struct msc_window *cur_win;
141 struct msc_window *switch_on_unlock;
142 unsigned long nr_pages;
143 unsigned long single_sz;
144 unsigned int single_wrap : 1;
145 void *base;
146 dma_addr_t base_addr;
147 u32 orig_addr;
148 u32 orig_sz;
149
150 /* <0: no buffer, 0: no users, >0: active users */
151 atomic_t user_count;
152
153 atomic_t mmap_count;
154 struct mutex buf_mutex;
155
156 struct list_head iter_list;
157
158 bool stop_on_full;
159
160 /* config */
161 unsigned int enabled : 1,
162 wrap : 1,
163 do_irq : 1,
164 multi_is_broken : 1;
165 unsigned int mode;
166 unsigned int burst_len;
167 unsigned int index;
168};
169
170static LIST_HEAD(msu_buffer_list);
171static DEFINE_MUTEX(msu_buffer_mutex);
172
173/**
174 * struct msu_buffer_entry - internal MSU buffer bookkeeping
175 * @entry: link to msu_buffer_list
176 * @mbuf: MSU buffer object
177 * @owner: module that provides this MSU buffer
178 */
179struct msu_buffer_entry {
180 struct list_head entry;
181 const struct msu_buffer *mbuf;
182 struct module *owner;
183};
184
185static struct msu_buffer_entry *__msu_buffer_entry_find(const char *name)
186{
187 struct msu_buffer_entry *mbe;
188
189 lockdep_assert_held(&msu_buffer_mutex);
190
191 list_for_each_entry(mbe, &msu_buffer_list, entry) {
192 if (!strcmp(mbe->mbuf->name, name))
193 return mbe;
194 }
195
196 return NULL;
197}
198
199static const struct msu_buffer *
200msu_buffer_get(const char *name)
201{
202 struct msu_buffer_entry *mbe;
203
204 mutex_lock(&msu_buffer_mutex);
205 mbe = __msu_buffer_entry_find(name);
206 if (mbe && !try_module_get(mbe->owner))
207 mbe = NULL;
208 mutex_unlock(&msu_buffer_mutex);
209
210 return mbe ? mbe->mbuf : NULL;
211}
212
213static void msu_buffer_put(const struct msu_buffer *mbuf)
214{
215 struct msu_buffer_entry *mbe;
216
217 mutex_lock(&msu_buffer_mutex);
218 mbe = __msu_buffer_entry_find(mbuf->name);
219 if (mbe)
220 module_put(mbe->owner);
221 mutex_unlock(&msu_buffer_mutex);
222}
223
224int intel_th_msu_buffer_register(const struct msu_buffer *mbuf,
225 struct module *owner)
226{
227 struct msu_buffer_entry *mbe;
228 int ret = 0;
229
230 mbe = kzalloc(sizeof(*mbe), GFP_KERNEL);
231 if (!mbe)
232 return -ENOMEM;
233
234 mutex_lock(&msu_buffer_mutex);
235 if (__msu_buffer_entry_find(mbuf->name)) {
236 ret = -EEXIST;
237 kfree(mbe);
238 goto unlock;
239 }
240
241 mbe->mbuf = mbuf;
242 mbe->owner = owner;
243 list_add_tail(&mbe->entry, &msu_buffer_list);
244unlock:
245 mutex_unlock(&msu_buffer_mutex);
246
247 return ret;
248}
249EXPORT_SYMBOL_GPL(intel_th_msu_buffer_register);
250
251void intel_th_msu_buffer_unregister(const struct msu_buffer *mbuf)
252{
253 struct msu_buffer_entry *mbe;
254
255 mutex_lock(&msu_buffer_mutex);
256 mbe = __msu_buffer_entry_find(mbuf->name);
257 if (mbe) {
258 list_del(&mbe->entry);
259 kfree(mbe);
260 }
261 mutex_unlock(&msu_buffer_mutex);
262}
263EXPORT_SYMBOL_GPL(intel_th_msu_buffer_unregister);
264
265static inline bool msc_block_is_empty(struct msc_block_desc *bdesc)
266{
267 /* header hasn't been written */
268 if (!bdesc->valid_dw)
269 return true;
270
271 /* valid_dw includes the header */
272 if (!msc_data_sz(bdesc))
273 return true;
274
275 return false;
276}
277
278static inline struct scatterlist *msc_win_base_sg(struct msc_window *win)
279{
280 return win->sgt->sgl;
281}
282
283static inline struct msc_block_desc *msc_win_base(struct msc_window *win)
284{
285 return sg_virt(msc_win_base_sg(win));
286}
287
288static inline dma_addr_t msc_win_base_dma(struct msc_window *win)
289{
290 return sg_dma_address(msc_win_base_sg(win));
291}
292
293static inline unsigned long
294msc_win_base_pfn(struct msc_window *win)
295{
296 return PFN_DOWN(msc_win_base_dma(win));
297}
298
299/**
300 * msc_is_last_win() - check if a window is the last one for a given MSC
301 * @win: window
302 * Return: true if @win is the last window in MSC's multiblock buffer
303 */
304static inline bool msc_is_last_win(struct msc_window *win)
305{
306 return win->entry.next == &win->msc->win_list;
307}
308
309/**
310 * msc_next_window() - return next window in the multiblock buffer
311 * @win: current window
312 *
313 * Return: window following the current one
314 */
315static struct msc_window *msc_next_window(struct msc_window *win)
316{
317 if (msc_is_last_win(win))
318 return list_first_entry(&win->msc->win_list, struct msc_window,
319 entry);
320
321 return list_next_entry(win, entry);
322}
323
324static size_t msc_win_total_sz(struct msc_window *win)
325{
326 struct scatterlist *sg;
327 unsigned int blk;
328 size_t size = 0;
329
330 for_each_sg(win->sgt->sgl, sg, win->nr_segs, blk) {
331 struct msc_block_desc *bdesc = sg_virt(sg);
332
333 if (msc_block_wrapped(bdesc))
334 return (size_t)win->nr_blocks << PAGE_SHIFT;
335
336 size += msc_total_sz(bdesc);
337 if (msc_block_last_written(bdesc))
338 break;
339 }
340
341 return size;
342}
343
344/**
345 * msc_find_window() - find a window matching a given sg_table
346 * @msc: MSC device
347 * @sgt: SG table of the window
348 * @nonempty: skip over empty windows
349 *
350 * Return: MSC window structure pointer or NULL if the window
351 * could not be found.
352 */
353static struct msc_window *
354msc_find_window(struct msc *msc, struct sg_table *sgt, bool nonempty)
355{
356 struct msc_window *win;
357 unsigned int found = 0;
358
359 if (list_empty(&msc->win_list))
360 return NULL;
361
362 /*
363 * we might need a radix tree for this, depending on how
364 * many windows a typical user would allocate; ideally it's
365 * something like 2, in which case we're good
366 */
367 list_for_each_entry(win, &msc->win_list, entry) {
368 if (win->sgt == sgt)
369 found++;
370
371 /* skip the empty ones */
372 if (nonempty && msc_block_is_empty(msc_win_base(win)))
373 continue;
374
375 if (found)
376 return win;
377 }
378
379 return NULL;
380}
381
382/**
383 * msc_oldest_window() - locate the window with oldest data
384 * @msc: MSC device
385 *
386 * This should only be used in multiblock mode. Caller should hold the
387 * msc::user_count reference.
388 *
389 * Return: the oldest window with valid data
390 */
391static struct msc_window *msc_oldest_window(struct msc *msc)
392{
393 struct msc_window *win;
394
395 if (list_empty(&msc->win_list))
396 return NULL;
397
398 win = msc_find_window(msc, msc_next_window(msc->cur_win)->sgt, true);
399 if (win)
400 return win;
401
402 return list_first_entry(&msc->win_list, struct msc_window, entry);
403}
404
405/**
406 * msc_win_oldest_sg() - locate the oldest block in a given window
407 * @win: window to look at
408 *
409 * Return: index of the block with the oldest data
410 */
411static struct scatterlist *msc_win_oldest_sg(struct msc_window *win)
412{
413 unsigned int blk;
414 struct scatterlist *sg;
415 struct msc_block_desc *bdesc = msc_win_base(win);
416
417 /* without wrapping, first block is the oldest */
418 if (!msc_block_wrapped(bdesc))
419 return msc_win_base_sg(win);
420
421 /*
422 * with wrapping, last written block contains both the newest and the
423 * oldest data for this window.
424 */
425 for_each_sg(win->sgt->sgl, sg, win->nr_segs, blk) {
426 struct msc_block_desc *bdesc = sg_virt(sg);
427
428 if (msc_block_last_written(bdesc))
429 return sg;
430 }
431
432 return msc_win_base_sg(win);
433}
434
435static struct msc_block_desc *msc_iter_bdesc(struct msc_iter *iter)
436{
437 return sg_virt(iter->block);
438}
439
440static struct msc_iter *msc_iter_install(struct msc *msc)
441{
442 struct msc_iter *iter;
443
444 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
445 if (!iter)
446 return ERR_PTR(-ENOMEM);
447
448 mutex_lock(&msc->buf_mutex);
449
450 /*
451 * Reading and tracing are mutually exclusive; if msc is
452 * enabled, open() will fail; otherwise existing readers
453 * will prevent enabling the msc and the rest of fops don't
454 * need to worry about it.
455 */
456 if (msc->enabled) {
457 kfree(iter);
458 iter = ERR_PTR(-EBUSY);
459 goto unlock;
460 }
461
462 iter->msc = msc;
463
464 list_add_tail(&iter->entry, &msc->iter_list);
465unlock:
466 mutex_unlock(&msc->buf_mutex);
467
468 return iter;
469}
470
471static void msc_iter_remove(struct msc_iter *iter, struct msc *msc)
472{
473 mutex_lock(&msc->buf_mutex);
474 list_del(&iter->entry);
475 mutex_unlock(&msc->buf_mutex);
476
477 kfree(iter);
478}
479
480static void msc_iter_block_start(struct msc_iter *iter)
481{
482 if (iter->start_block)
483 return;
484
485 iter->start_block = msc_win_oldest_sg(iter->win);
486 iter->block = iter->start_block;
487 iter->wrap_count = 0;
488
489 /*
490 * start with the block with oldest data; if data has wrapped
491 * in this window, it should be in this block
492 */
493 if (msc_block_wrapped(msc_iter_bdesc(iter)))
494 iter->wrap_count = 2;
495
496}
497
498static int msc_iter_win_start(struct msc_iter *iter, struct msc *msc)
499{
500 /* already started, nothing to do */
501 if (iter->start_win)
502 return 0;
503
504 iter->start_win = msc_oldest_window(msc);
505 if (!iter->start_win)
506 return -EINVAL;
507
508 iter->win = iter->start_win;
509 iter->start_block = NULL;
510
511 msc_iter_block_start(iter);
512
513 return 0;
514}
515
516static int msc_iter_win_advance(struct msc_iter *iter)
517{
518 iter->win = msc_next_window(iter->win);
519 iter->start_block = NULL;
520
521 if (iter->win == iter->start_win) {
522 iter->eof++;
523 return 1;
524 }
525
526 msc_iter_block_start(iter);
527
528 return 0;
529}
530
531static int msc_iter_block_advance(struct msc_iter *iter)
532{
533 iter->block_off = 0;
534
535 /* wrapping */
536 if (iter->wrap_count && iter->block == iter->start_block) {
537 iter->wrap_count--;
538 if (!iter->wrap_count)
539 /* copied newest data from the wrapped block */
540 return msc_iter_win_advance(iter);
541 }
542
543 /* no wrapping, check for last written block */
544 if (!iter->wrap_count && msc_block_last_written(msc_iter_bdesc(iter)))
545 /* copied newest data for the window */
546 return msc_iter_win_advance(iter);
547
548 /* block advance */
549 if (sg_is_last(iter->block))
550 iter->block = msc_win_base_sg(iter->win);
551 else
552 iter->block = sg_next(iter->block);
553
554 /* no wrapping, sanity check in case there is no last written block */
555 if (!iter->wrap_count && iter->block == iter->start_block)
556 return msc_iter_win_advance(iter);
557
558 return 0;
559}
560
561/**
562 * msc_buffer_iterate() - go through multiblock buffer's data
563 * @iter: iterator structure
564 * @size: amount of data to scan
565 * @data: callback's private data
566 * @fn: iterator callback
567 *
568 * This will start at the window which will be written to next (containing
569 * the oldest data) and work its way to the current window, calling @fn
570 * for each chunk of data as it goes.
571 *
572 * Caller should have msc::user_count reference to make sure the buffer
573 * doesn't disappear from under us.
574 *
575 * Return: amount of data actually scanned.
576 */
577static ssize_t
578msc_buffer_iterate(struct msc_iter *iter, size_t size, void *data,
579 unsigned long (*fn)(void *, void *, size_t))
580{
581 struct msc *msc = iter->msc;
582 size_t len = size;
583 unsigned int advance;
584
585 if (iter->eof)
586 return 0;
587
588 /* start with the oldest window */
589 if (msc_iter_win_start(iter, msc))
590 return 0;
591
592 do {
593 unsigned long data_bytes = msc_data_sz(msc_iter_bdesc(iter));
594 void *src = (void *)msc_iter_bdesc(iter) + MSC_BDESC;
595 size_t tocopy = data_bytes, copied = 0;
596 size_t remaining = 0;
597
598 advance = 1;
599
600 /*
601 * If block wrapping happened, we need to visit the last block
602 * twice, because it contains both the oldest and the newest
603 * data in this window.
604 *
605 * First time (wrap_count==2), in the very beginning, to collect
606 * the oldest data, which is in the range
607 * (data_bytes..DATA_IN_PAGE).
608 *
609 * Second time (wrap_count==1), it's just like any other block,
610 * containing data in the range of [MSC_BDESC..data_bytes].
611 */
612 if (iter->block == iter->start_block && iter->wrap_count == 2) {
613 tocopy = DATA_IN_PAGE - data_bytes;
614 src += data_bytes;
615 }
616
617 if (!tocopy)
618 goto next_block;
619
620 tocopy -= iter->block_off;
621 src += iter->block_off;
622
623 if (len < tocopy) {
624 tocopy = len;
625 advance = 0;
626 }
627
628 remaining = fn(data, src, tocopy);
629
630 if (remaining)
631 advance = 0;
632
633 copied = tocopy - remaining;
634 len -= copied;
635 iter->block_off += copied;
636 iter->offset += copied;
637
638 if (!advance)
639 break;
640
641next_block:
642 if (msc_iter_block_advance(iter))
643 break;
644
645 } while (len);
646
647 return size - len;
648}
649
650/**
651 * msc_buffer_clear_hw_header() - clear hw header for multiblock
652 * @msc: MSC device
653 */
654static void msc_buffer_clear_hw_header(struct msc *msc)
655{
656 struct msc_window *win;
657 struct scatterlist *sg;
658
659 list_for_each_entry(win, &msc->win_list, entry) {
660 unsigned int blk;
661
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 */
759static int msc_configure(struct msc *msc)
760{
761 u32 reg;
762
763 lockdep_assert_held(&msc->buf_mutex);
764
765 if (msc->mode > MSC_MODE_MULTI)
766 return -EINVAL;
767
768 if (msc->mode == MSC_MODE_MULTI) {
769 if (msc_win_set_lockout(msc->cur_win, WIN_READY, WIN_INUSE))
770 return -EBUSY;
771
772 msc_buffer_clear_hw_header(msc);
773 }
774
775 msc->orig_addr = ioread32(msc->reg_base + REG_MSU_MSC0BAR);
776 msc->orig_sz = ioread32(msc->reg_base + REG_MSU_MSC0SIZE);
777
778 reg = msc->base_addr >> PAGE_SHIFT;
779 iowrite32(reg, msc->reg_base + REG_MSU_MSC0BAR);
780
781 if (msc->mode == MSC_MODE_SINGLE) {
782 reg = msc->nr_pages;
783 iowrite32(reg, msc->reg_base + REG_MSU_MSC0SIZE);
784 }
785
786 reg = ioread32(msc->reg_base + REG_MSU_MSC0CTL);
787 reg &= ~(MSC_MODE | MSC_WRAPEN | MSC_EN | MSC_RD_HDR_OVRD);
788
789 reg |= MSC_EN;
790 reg |= msc->mode << __ffs(MSC_MODE);
791 reg |= msc->burst_len << __ffs(MSC_LEN);
792
793 if (msc->wrap)
794 reg |= MSC_WRAPEN;
795
796 iowrite32(reg, msc->reg_base + REG_MSU_MSC0CTL);
797
798 intel_th_msu_init(msc);
799
800 msc->thdev->output.multiblock = msc->mode == MSC_MODE_MULTI;
801 intel_th_trace_enable(msc->thdev);
802 msc->enabled = 1;
803
804 if (msc->mbuf && msc->mbuf->activate)
805 msc->mbuf->activate(msc->mbuf_priv);
806
807 return 0;
808}
809
810/**
811 * msc_disable() - disable MSC hardware
812 * @msc: MSC device to disable
813 *
814 * If @msc is enabled, disable tracing on the switch and then disable MSC
815 * storage. Caller must hold msc::buf_mutex.
816 */
817static void msc_disable(struct msc *msc)
818{
819 struct msc_window *win = msc->cur_win;
820 u32 reg;
821
822 lockdep_assert_held(&msc->buf_mutex);
823
824 if (msc->mode == MSC_MODE_MULTI)
825 msc_win_set_lockout(win, WIN_INUSE, WIN_LOCKED);
826
827 if (msc->mbuf && msc->mbuf->deactivate)
828 msc->mbuf->deactivate(msc->mbuf_priv);
829 intel_th_msu_deinit(msc);
830 intel_th_trace_disable(msc->thdev);
831
832 if (msc->mode == MSC_MODE_SINGLE) {
833 reg = ioread32(msc->reg_base + REG_MSU_MSC0STS);
834 msc->single_wrap = !!(reg & MSCSTS_WRAPSTAT);
835
836 reg = ioread32(msc->reg_base + REG_MSU_MSC0MWP);
837 msc->single_sz = reg & ((msc->nr_pages << PAGE_SHIFT) - 1);
838 dev_dbg(msc_dev(msc), "MSCnMWP: %08x/%08lx, wrap: %d\n",
839 reg, msc->single_sz, msc->single_wrap);
840 }
841
842 reg = ioread32(msc->reg_base + REG_MSU_MSC0CTL);
843 reg &= ~MSC_EN;
844 iowrite32(reg, msc->reg_base + REG_MSU_MSC0CTL);
845
846 if (msc->mbuf && msc->mbuf->ready)
847 msc->mbuf->ready(msc->mbuf_priv, win->sgt,
848 msc_win_total_sz(win));
849
850 msc->enabled = 0;
851
852 iowrite32(msc->orig_addr, msc->reg_base + REG_MSU_MSC0BAR);
853 iowrite32(msc->orig_sz, msc->reg_base + REG_MSU_MSC0SIZE);
854
855 dev_dbg(msc_dev(msc), "MSCnNWSA: %08x\n",
856 ioread32(msc->reg_base + REG_MSU_MSC0NWSA));
857
858 reg = ioread32(msc->reg_base + REG_MSU_MSC0STS);
859 dev_dbg(msc_dev(msc), "MSCnSTS: %08x\n", reg);
860
861 reg = ioread32(msc->reg_base + REG_MSU_MSUSTS);
862 reg &= msc->index ? MSUSTS_MSC1BLAST : MSUSTS_MSC0BLAST;
863 iowrite32(reg, msc->reg_base + REG_MSU_MSUSTS);
864}
865
866static int intel_th_msc_activate(struct intel_th_device *thdev)
867{
868 struct msc *msc = dev_get_drvdata(&thdev->dev);
869 int ret = -EBUSY;
870
871 if (!atomic_inc_unless_negative(&msc->user_count))
872 return -ENODEV;
873
874 mutex_lock(&msc->buf_mutex);
875
876 /* if there are readers, refuse */
877 if (list_empty(&msc->iter_list))
878 ret = msc_configure(msc);
879
880 mutex_unlock(&msc->buf_mutex);
881
882 if (ret)
883 atomic_dec(&msc->user_count);
884
885 return ret;
886}
887
888static void intel_th_msc_deactivate(struct intel_th_device *thdev)
889{
890 struct msc *msc = dev_get_drvdata(&thdev->dev);
891
892 mutex_lock(&msc->buf_mutex);
893 if (msc->enabled) {
894 msc_disable(msc);
895 atomic_dec(&msc->user_count);
896 }
897 mutex_unlock(&msc->buf_mutex);
898}
899
900/**
901 * msc_buffer_contig_alloc() - allocate a contiguous buffer for SINGLE mode
902 * @msc: MSC device
903 * @size: allocation size in bytes
904 *
905 * This modifies msc::base, which requires msc::buf_mutex to serialize, so the
906 * caller is expected to hold it.
907 *
908 * Return: 0 on success, -errno otherwise.
909 */
910static int msc_buffer_contig_alloc(struct msc *msc, unsigned long size)
911{
912 unsigned long nr_pages = size >> PAGE_SHIFT;
913 unsigned int order = get_order(size);
914 struct page *page;
915 int ret;
916
917 if (!size)
918 return 0;
919
920 ret = sg_alloc_table(&msc->single_sgt, 1, GFP_KERNEL);
921 if (ret)
922 goto err_out;
923
924 ret = -ENOMEM;
925 page = alloc_pages(GFP_KERNEL | __GFP_ZERO | GFP_DMA32, order);
926 if (!page)
927 goto err_free_sgt;
928
929 split_page(page, order);
930 sg_set_buf(msc->single_sgt.sgl, page_address(page), size);
931
932 ret = dma_map_sg(msc_dev(msc)->parent->parent, msc->single_sgt.sgl, 1,
933 DMA_FROM_DEVICE);
934 if (ret < 0)
935 goto err_free_pages;
936
937 msc->nr_pages = nr_pages;
938 msc->base = page_address(page);
939 msc->base_addr = sg_dma_address(msc->single_sgt.sgl);
940
941 return 0;
942
943err_free_pages:
944 __free_pages(page, order);
945
946err_free_sgt:
947 sg_free_table(&msc->single_sgt);
948
949err_out:
950 return ret;
951}
952
953/**
954 * msc_buffer_contig_free() - free a contiguous buffer
955 * @msc: MSC configured in SINGLE mode
956 */
957static void msc_buffer_contig_free(struct msc *msc)
958{
959 unsigned long off;
960
961 dma_unmap_sg(msc_dev(msc)->parent->parent, msc->single_sgt.sgl,
962 1, DMA_FROM_DEVICE);
963 sg_free_table(&msc->single_sgt);
964
965 for (off = 0; off < msc->nr_pages << PAGE_SHIFT; off += PAGE_SIZE) {
966 struct page *page = virt_to_page(msc->base + off);
967
968 page->mapping = NULL;
969 __free_page(page);
970 }
971
972 msc->nr_pages = 0;
973}
974
975/**
976 * msc_buffer_contig_get_page() - find a page at a given offset
977 * @msc: MSC configured in SINGLE mode
978 * @pgoff: page offset
979 *
980 * Return: page, if @pgoff is within the range, NULL otherwise.
981 */
982static struct page *msc_buffer_contig_get_page(struct msc *msc,
983 unsigned long pgoff)
984{
985 if (pgoff >= msc->nr_pages)
986 return NULL;
987
988 return virt_to_page(msc->base + (pgoff << PAGE_SHIFT));
989}
990
991static int __msc_buffer_win_alloc(struct msc_window *win,
992 unsigned int nr_segs)
993{
994 struct scatterlist *sg_ptr;
995 void *block;
996 int i, ret;
997
998 ret = sg_alloc_table(win->sgt, nr_segs, GFP_KERNEL);
999 if (ret)
1000 return -ENOMEM;
1001
1002 for_each_sg(win->sgt->sgl, sg_ptr, nr_segs, i) {
1003 block = dma_alloc_coherent(msc_dev(win->msc)->parent->parent,
1004 PAGE_SIZE, &sg_dma_address(sg_ptr),
1005 GFP_KERNEL);
1006 if (!block)
1007 goto err_nomem;
1008
1009 sg_set_buf(sg_ptr, block, PAGE_SIZE);
1010 }
1011
1012 return nr_segs;
1013
1014err_nomem:
1015 for_each_sg(win->sgt->sgl, sg_ptr, i, ret)
1016 dma_free_coherent(msc_dev(win->msc)->parent->parent, PAGE_SIZE,
1017 sg_virt(sg_ptr), sg_dma_address(sg_ptr));
1018
1019 sg_free_table(win->sgt);
1020
1021 return -ENOMEM;
1022}
1023
1024#ifdef CONFIG_X86
1025static void msc_buffer_set_uc(struct msc *msc)
1026{
1027 struct scatterlist *sg_ptr;
1028 struct msc_window *win;
1029 int i;
1030
1031 if (msc->mode == MSC_MODE_SINGLE) {
1032 set_memory_uc((unsigned long)msc->base, msc->nr_pages);
1033 return;
1034 }
1035
1036 list_for_each_entry(win, &msc->win_list, entry) {
1037 for_each_sg(win->sgt->sgl, sg_ptr, win->nr_segs, i) {
1038 /* Set the page as uncached */
1039 set_memory_uc((unsigned long)sg_virt(sg_ptr),
1040 PFN_DOWN(sg_ptr->length));
1041 }
1042 }
1043}
1044
1045static void msc_buffer_set_wb(struct msc *msc)
1046{
1047 struct scatterlist *sg_ptr;
1048 struct msc_window *win;
1049 int i;
1050
1051 if (msc->mode == MSC_MODE_SINGLE) {
1052 set_memory_wb((unsigned long)msc->base, msc->nr_pages);
1053 return;
1054 }
1055
1056 list_for_each_entry(win, &msc->win_list, entry) {
1057 for_each_sg(win->sgt->sgl, sg_ptr, win->nr_segs, i) {
1058 /* Reset the page to write-back */
1059 set_memory_wb((unsigned long)sg_virt(sg_ptr),
1060 PFN_DOWN(sg_ptr->length));
1061 }
1062 }
1063}
1064#else /* !X86 */
1065static inline void
1066msc_buffer_set_uc(struct msc *msc) {}
1067static inline void msc_buffer_set_wb(struct msc *msc) {}
1068#endif /* CONFIG_X86 */
1069
1070static struct page *msc_sg_page(struct scatterlist *sg)
1071{
1072 void *addr = sg_virt(sg);
1073
1074 if (is_vmalloc_addr(addr))
1075 return vmalloc_to_page(addr);
1076
1077 return sg_page(sg);
1078}
1079
1080/**
1081 * msc_buffer_win_alloc() - alloc a window for a multiblock mode
1082 * @msc: MSC device
1083 * @nr_blocks: number of pages in this window
1084 *
1085 * This modifies msc::win_list and msc::base, which requires msc::buf_mutex
1086 * to serialize, so the caller is expected to hold it.
1087 *
1088 * Return: 0 on success, -errno otherwise.
1089 */
1090static int msc_buffer_win_alloc(struct msc *msc, unsigned int nr_blocks)
1091{
1092 struct msc_window *win;
1093 int ret = -ENOMEM;
1094
1095 if (!nr_blocks)
1096 return 0;
1097
1098 win = kzalloc(sizeof(*win), GFP_KERNEL);
1099 if (!win)
1100 return -ENOMEM;
1101
1102 win->msc = msc;
1103 win->sgt = &win->_sgt;
1104 win->lockout = WIN_READY;
1105 spin_lock_init(&win->lo_lock);
1106
1107 if (!list_empty(&msc->win_list)) {
1108 struct msc_window *prev = list_last_entry(&msc->win_list,
1109 struct msc_window,
1110 entry);
1111
1112 win->pgoff = prev->pgoff + prev->nr_blocks;
1113 }
1114
1115 if (msc->mbuf && msc->mbuf->alloc_window)
1116 ret = msc->mbuf->alloc_window(msc->mbuf_priv, &win->sgt,
1117 nr_blocks << PAGE_SHIFT);
1118 else
1119 ret = __msc_buffer_win_alloc(win, nr_blocks);
1120
1121 if (ret <= 0)
1122 goto err_nomem;
1123
1124 win->nr_segs = ret;
1125 win->nr_blocks = nr_blocks;
1126
1127 if (list_empty(&msc->win_list)) {
1128 msc->base = msc_win_base(win);
1129 msc->base_addr = msc_win_base_dma(win);
1130 msc->cur_win = win;
1131 }
1132
1133 list_add_tail(&win->entry, &msc->win_list);
1134 msc->nr_pages += nr_blocks;
1135
1136 return 0;
1137
1138err_nomem:
1139 kfree(win);
1140
1141 return ret;
1142}
1143
1144static void __msc_buffer_win_free(struct msc *msc, struct msc_window *win)
1145{
1146 struct scatterlist *sg;
1147 int i;
1148
1149 for_each_sg(win->sgt->sgl, sg, win->nr_segs, i) {
1150 struct page *page = msc_sg_page(sg);
1151
1152 page->mapping = NULL;
1153 dma_free_coherent(msc_dev(win->msc)->parent->parent, PAGE_SIZE,
1154 sg_virt(sg), sg_dma_address(sg));
1155 }
1156 sg_free_table(win->sgt);
1157}
1158
1159/**
1160 * msc_buffer_win_free() - free a window from MSC's window list
1161 * @msc: MSC device
1162 * @win: window to free
1163 *
1164 * This modifies msc::win_list and msc::base, which requires msc::buf_mutex
1165 * to serialize, so the caller is expected to hold it.
1166 */
1167static void msc_buffer_win_free(struct msc *msc, struct msc_window *win)
1168{
1169 msc->nr_pages -= win->nr_blocks;
1170
1171 list_del(&win->entry);
1172 if (list_empty(&msc->win_list)) {
1173 msc->base = NULL;
1174 msc->base_addr = 0;
1175 }
1176
1177 if (msc->mbuf && msc->mbuf->free_window)
1178 msc->mbuf->free_window(msc->mbuf_priv, win->sgt);
1179 else
1180 __msc_buffer_win_free(msc, win);
1181
1182 kfree(win);
1183}
1184
1185/**
1186 * msc_buffer_relink() - set up block descriptors for multiblock mode
1187 * @msc: MSC device
1188 *
1189 * This traverses msc::win_list, which requires msc::buf_mutex to serialize,
1190 * so the caller is expected to hold it.
1191 */
1192static void msc_buffer_relink(struct msc *msc)
1193{
1194 struct msc_window *win, *next_win;
1195
1196 /* call with msc::mutex locked */
1197 list_for_each_entry(win, &msc->win_list, entry) {
1198 struct scatterlist *sg;
1199 unsigned int blk;
1200 u32 sw_tag = 0;
1201
1202 /*
1203 * Last window's next_win should point to the first window
1204 * and MSC_SW_TAG_LASTWIN should be set.
1205 */
1206 if (msc_is_last_win(win)) {
1207 sw_tag |= MSC_SW_TAG_LASTWIN;
1208 next_win = list_first_entry(&msc->win_list,
1209 struct msc_window, entry);
1210 } else {
1211 next_win = list_next_entry(win, entry);
1212 }
1213
1214 for_each_sg(win->sgt->sgl, sg, win->nr_segs, blk) {
1215 struct msc_block_desc *bdesc = sg_virt(sg);
1216
1217 memset(bdesc, 0, sizeof(*bdesc));
1218
1219 bdesc->next_win = msc_win_base_pfn(next_win);
1220
1221 /*
1222 * Similarly to last window, last block should point
1223 * to the first one.
1224 */
1225 if (blk == win->nr_segs - 1) {
1226 sw_tag |= MSC_SW_TAG_LASTBLK;
1227 bdesc->next_blk = msc_win_base_pfn(win);
1228 } else {
1229 dma_addr_t addr = sg_dma_address(sg_next(sg));
1230
1231 bdesc->next_blk = PFN_DOWN(addr);
1232 }
1233
1234 bdesc->sw_tag = sw_tag;
1235 bdesc->block_sz = sg->length / 64;
1236 }
1237 }
1238
1239 /*
1240 * Make the above writes globally visible before tracing is
1241 * enabled to make sure hardware sees them coherently.
1242 */
1243 wmb();
1244}
1245
1246static void msc_buffer_multi_free(struct msc *msc)
1247{
1248 struct msc_window *win, *iter;
1249
1250 list_for_each_entry_safe(win, iter, &msc->win_list, entry)
1251 msc_buffer_win_free(msc, win);
1252}
1253
1254static int msc_buffer_multi_alloc(struct msc *msc, unsigned long *nr_pages,
1255 unsigned int nr_wins)
1256{
1257 int ret, i;
1258
1259 for (i = 0; i < nr_wins; i++) {
1260 ret = msc_buffer_win_alloc(msc, nr_pages[i]);
1261 if (ret) {
1262 msc_buffer_multi_free(msc);
1263 return ret;
1264 }
1265 }
1266
1267 msc_buffer_relink(msc);
1268
1269 return 0;
1270}
1271
1272/**
1273 * msc_buffer_free() - free buffers for MSC
1274 * @msc: MSC device
1275 *
1276 * Free MSC's storage buffers.
1277 *
1278 * This modifies msc::win_list and msc::base, which requires msc::buf_mutex to
1279 * serialize, so the caller is expected to hold it.
1280 */
1281static void msc_buffer_free(struct msc *msc)
1282{
1283 msc_buffer_set_wb(msc);
1284
1285 if (msc->mode == MSC_MODE_SINGLE)
1286 msc_buffer_contig_free(msc);
1287 else if (msc->mode == MSC_MODE_MULTI)
1288 msc_buffer_multi_free(msc);
1289}
1290
1291/**
1292 * msc_buffer_alloc() - allocate a buffer for MSC
1293 * @msc: MSC device
1294 * @size: allocation size in bytes
1295 *
1296 * Allocate a storage buffer for MSC, depending on the msc::mode, it will be
1297 * either done via msc_buffer_contig_alloc() for SINGLE operation mode or
1298 * msc_buffer_win_alloc() for multiblock operation. The latter allocates one
1299 * window per invocation, so in multiblock mode this can be called multiple
1300 * times for the same MSC to allocate multiple windows.
1301 *
1302 * This modifies msc::win_list and msc::base, which requires msc::buf_mutex
1303 * to serialize, so the caller is expected to hold it.
1304 *
1305 * Return: 0 on success, -errno otherwise.
1306 */
1307static int msc_buffer_alloc(struct msc *msc, unsigned long *nr_pages,
1308 unsigned int nr_wins)
1309{
1310 int ret;
1311
1312 /* -1: buffer not allocated */
1313 if (atomic_read(&msc->user_count) != -1)
1314 return -EBUSY;
1315
1316 if (msc->mode == MSC_MODE_SINGLE) {
1317 if (nr_wins != 1)
1318 return -EINVAL;
1319
1320 ret = msc_buffer_contig_alloc(msc, nr_pages[0] << PAGE_SHIFT);
1321 } else if (msc->mode == MSC_MODE_MULTI) {
1322 ret = msc_buffer_multi_alloc(msc, nr_pages, nr_wins);
1323 } else {
1324 ret = -EINVAL;
1325 }
1326
1327 if (!ret) {
1328 msc_buffer_set_uc(msc);
1329
1330 /* allocation should be visible before the counter goes to 0 */
1331 smp_mb__before_atomic();
1332
1333 if (WARN_ON_ONCE(atomic_cmpxchg(&msc->user_count, -1, 0) != -1))
1334 return -EINVAL;
1335 }
1336
1337 return ret;
1338}
1339
1340/**
1341 * msc_buffer_unlocked_free_unless_used() - free a buffer unless it's in use
1342 * @msc: MSC device
1343 *
1344 * This will free MSC buffer unless it is in use or there is no allocated
1345 * buffer.
1346 * Caller needs to hold msc::buf_mutex.
1347 *
1348 * Return: 0 on successful deallocation or if there was no buffer to
1349 * deallocate, -EBUSY if there are active users.
1350 */
1351static int msc_buffer_unlocked_free_unless_used(struct msc *msc)
1352{
1353 int count, ret = 0;
1354
1355 count = atomic_cmpxchg(&msc->user_count, 0, -1);
1356
1357 /* > 0: buffer is allocated and has users */
1358 if (count > 0)
1359 ret = -EBUSY;
1360 /* 0: buffer is allocated, no users */
1361 else if (!count)
1362 msc_buffer_free(msc);
1363 /* < 0: no buffer, nothing to do */
1364
1365 return ret;
1366}
1367
1368/**
1369 * msc_buffer_free_unless_used() - free a buffer unless it's in use
1370 * @msc: MSC device
1371 *
1372 * This is a locked version of msc_buffer_unlocked_free_unless_used().
1373 */
1374static int msc_buffer_free_unless_used(struct msc *msc)
1375{
1376 int ret;
1377
1378 mutex_lock(&msc->buf_mutex);
1379 ret = msc_buffer_unlocked_free_unless_used(msc);
1380 mutex_unlock(&msc->buf_mutex);
1381
1382 return ret;
1383}
1384
1385/**
1386 * msc_buffer_get_page() - get MSC buffer page at a given offset
1387 * @msc: MSC device
1388 * @pgoff: page offset into the storage buffer
1389 *
1390 * This traverses msc::win_list, so holding msc::buf_mutex is expected from
1391 * the caller.
1392 *
1393 * Return: page if @pgoff corresponds to a valid buffer page or NULL.
1394 */
1395static struct page *msc_buffer_get_page(struct msc *msc, unsigned long pgoff)
1396{
1397 struct msc_window *win;
1398 struct scatterlist *sg;
1399 unsigned int blk;
1400
1401 if (msc->mode == MSC_MODE_SINGLE)
1402 return msc_buffer_contig_get_page(msc, pgoff);
1403
1404 list_for_each_entry(win, &msc->win_list, entry)
1405 if (pgoff >= win->pgoff && pgoff < win->pgoff + win->nr_blocks)
1406 goto found;
1407
1408 return NULL;
1409
1410found:
1411 pgoff -= win->pgoff;
1412
1413 for_each_sg(win->sgt->sgl, sg, win->nr_segs, blk) {
1414 struct page *page = msc_sg_page(sg);
1415 size_t pgsz = PFN_DOWN(sg->length);
1416
1417 if (pgoff < pgsz)
1418 return page + pgoff;
1419
1420 pgoff -= pgsz;
1421 }
1422
1423 return NULL;
1424}
1425
1426/**
1427 * struct msc_win_to_user_struct - data for copy_to_user() callback
1428 * @buf: userspace buffer to copy data to
1429 * @offset: running offset
1430 */
1431struct msc_win_to_user_struct {
1432 char __user *buf;
1433 unsigned long offset;
1434};
1435
1436/**
1437 * msc_win_to_user() - iterator for msc_buffer_iterate() to copy data to user
1438 * @data: callback's private data
1439 * @src: source buffer
1440 * @len: amount of data to copy from the source buffer
1441 */
1442static unsigned long msc_win_to_user(void *data, void *src, size_t len)
1443{
1444 struct msc_win_to_user_struct *u = data;
1445 unsigned long ret;
1446
1447 ret = copy_to_user(u->buf + u->offset, src, len);
1448 u->offset += len - ret;
1449
1450 return ret;
1451}
1452
1453
1454/*
1455 * file operations' callbacks
1456 */
1457
1458static int intel_th_msc_open(struct inode *inode, struct file *file)
1459{
1460 struct intel_th_device *thdev = file->private_data;
1461 struct msc *msc = dev_get_drvdata(&thdev->dev);
1462 struct msc_iter *iter;
1463
1464 if (!capable(CAP_SYS_RAWIO))
1465 return -EPERM;
1466
1467 iter = msc_iter_install(msc);
1468 if (IS_ERR(iter))
1469 return PTR_ERR(iter);
1470
1471 file->private_data = iter;
1472
1473 return nonseekable_open(inode, file);
1474}
1475
1476static int intel_th_msc_release(struct inode *inode, struct file *file)
1477{
1478 struct msc_iter *iter = file->private_data;
1479 struct msc *msc = iter->msc;
1480
1481 msc_iter_remove(iter, msc);
1482
1483 return 0;
1484}
1485
1486static ssize_t
1487msc_single_to_user(struct msc *msc, char __user *buf, loff_t off, size_t len)
1488{
1489 unsigned long size = msc->nr_pages << PAGE_SHIFT, rem = len;
1490 unsigned long start = off, tocopy = 0;
1491
1492 if (msc->single_wrap) {
1493 start += msc->single_sz;
1494 if (start < size) {
1495 tocopy = min(rem, size - start);
1496 if (copy_to_user(buf, msc->base + start, tocopy))
1497 return -EFAULT;
1498
1499 buf += tocopy;
1500 rem -= tocopy;
1501 start += tocopy;
1502 }
1503
1504 start &= size - 1;
1505 if (rem) {
1506 tocopy = min(rem, msc->single_sz - start);
1507 if (copy_to_user(buf, msc->base + start, tocopy))
1508 return -EFAULT;
1509
1510 rem -= tocopy;
1511 }
1512
1513 return len - rem;
1514 }
1515
1516 if (copy_to_user(buf, msc->base + start, rem))
1517 return -EFAULT;
1518
1519 return len;
1520}
1521
1522static ssize_t intel_th_msc_read(struct file *file, char __user *buf,
1523 size_t len, loff_t *ppos)
1524{
1525 struct msc_iter *iter = file->private_data;
1526 struct msc *msc = iter->msc;
1527 size_t size;
1528 loff_t off = *ppos;
1529 ssize_t ret = 0;
1530
1531 if (!atomic_inc_unless_negative(&msc->user_count))
1532 return 0;
1533
1534 if (msc->mode == MSC_MODE_SINGLE && !msc->single_wrap)
1535 size = msc->single_sz;
1536 else
1537 size = msc->nr_pages << PAGE_SHIFT;
1538
1539 if (!size)
1540 goto put_count;
1541
1542 if (off >= size)
1543 goto put_count;
1544
1545 if (off + len >= size)
1546 len = size - off;
1547
1548 if (msc->mode == MSC_MODE_SINGLE) {
1549 ret = msc_single_to_user(msc, buf, off, len);
1550 if (ret >= 0)
1551 *ppos += ret;
1552 } else if (msc->mode == MSC_MODE_MULTI) {
1553 struct msc_win_to_user_struct u = {
1554 .buf = buf,
1555 .offset = 0,
1556 };
1557
1558 ret = msc_buffer_iterate(iter, len, &u, msc_win_to_user);
1559 if (ret >= 0)
1560 *ppos = iter->offset;
1561 } else {
1562 ret = -EINVAL;
1563 }
1564
1565put_count:
1566 atomic_dec(&msc->user_count);
1567
1568 return ret;
1569}
1570
1571/*
1572 * vm operations callbacks (vm_ops)
1573 */
1574
1575static void msc_mmap_open(struct vm_area_struct *vma)
1576{
1577 struct msc_iter *iter = vma->vm_file->private_data;
1578 struct msc *msc = iter->msc;
1579
1580 atomic_inc(&msc->mmap_count);
1581}
1582
1583static void msc_mmap_close(struct vm_area_struct *vma)
1584{
1585 struct msc_iter *iter = vma->vm_file->private_data;
1586 struct msc *msc = iter->msc;
1587 unsigned long pg;
1588
1589 if (!atomic_dec_and_mutex_lock(&msc->mmap_count, &msc->buf_mutex))
1590 return;
1591
1592 /* drop page _refcounts */
1593 for (pg = 0; pg < msc->nr_pages; pg++) {
1594 struct page *page = msc_buffer_get_page(msc, pg);
1595
1596 if (WARN_ON_ONCE(!page))
1597 continue;
1598
1599 if (page->mapping)
1600 page->mapping = NULL;
1601 }
1602
1603 /* last mapping -- drop user_count */
1604 atomic_dec(&msc->user_count);
1605 mutex_unlock(&msc->buf_mutex);
1606}
1607
1608static vm_fault_t msc_mmap_fault(struct vm_fault *vmf)
1609{
1610 struct msc_iter *iter = vmf->vma->vm_file->private_data;
1611 struct msc *msc = iter->msc;
1612
1613 vmf->page = msc_buffer_get_page(msc, vmf->pgoff);
1614 if (!vmf->page)
1615 return VM_FAULT_SIGBUS;
1616
1617 get_page(vmf->page);
1618 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
1619 vmf->page->index = vmf->pgoff;
1620
1621 return 0;
1622}
1623
1624static const struct vm_operations_struct msc_mmap_ops = {
1625 .open = msc_mmap_open,
1626 .close = msc_mmap_close,
1627 .fault = msc_mmap_fault,
1628};
1629
1630static int intel_th_msc_mmap(struct file *file, struct vm_area_struct *vma)
1631{
1632 unsigned long size = vma->vm_end - vma->vm_start;
1633 struct msc_iter *iter = vma->vm_file->private_data;
1634 struct msc *msc = iter->msc;
1635 int ret = -EINVAL;
1636
1637 if (!size || offset_in_page(size))
1638 return -EINVAL;
1639
1640 if (vma->vm_pgoff)
1641 return -EINVAL;
1642
1643 /* grab user_count once per mmap; drop in msc_mmap_close() */
1644 if (!atomic_inc_unless_negative(&msc->user_count))
1645 return -EINVAL;
1646
1647 if (msc->mode != MSC_MODE_SINGLE &&
1648 msc->mode != MSC_MODE_MULTI)
1649 goto out;
1650
1651 if (size >> PAGE_SHIFT != msc->nr_pages)
1652 goto out;
1653
1654 atomic_set(&msc->mmap_count, 1);
1655 ret = 0;
1656
1657out:
1658 if (ret)
1659 atomic_dec(&msc->user_count);
1660
1661 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
1662 vm_flags_set(vma, VM_DONTEXPAND | VM_DONTCOPY);
1663 vma->vm_ops = &msc_mmap_ops;
1664 return ret;
1665}
1666
1667static const struct file_operations intel_th_msc_fops = {
1668 .open = intel_th_msc_open,
1669 .release = intel_th_msc_release,
1670 .read = intel_th_msc_read,
1671 .mmap = intel_th_msc_mmap,
1672 .llseek = no_llseek,
1673 .owner = THIS_MODULE,
1674};
1675
1676static void intel_th_msc_wait_empty(struct intel_th_device *thdev)
1677{
1678 struct msc *msc = dev_get_drvdata(&thdev->dev);
1679 unsigned long count;
1680 u32 reg;
1681
1682 for (reg = 0, count = MSC_PLE_WAITLOOP_DEPTH;
1683 count && !(reg & MSCSTS_PLE); count--) {
1684 reg = __raw_readl(msc->reg_base + REG_MSU_MSC0STS);
1685 cpu_relax();
1686 }
1687
1688 if (!count)
1689 dev_dbg(msc_dev(msc), "timeout waiting for MSC0 PLE\n");
1690}
1691
1692static int intel_th_msc_init(struct msc *msc)
1693{
1694 atomic_set(&msc->user_count, -1);
1695
1696 msc->mode = msc->multi_is_broken ? MSC_MODE_SINGLE : MSC_MODE_MULTI;
1697 mutex_init(&msc->buf_mutex);
1698 INIT_LIST_HEAD(&msc->win_list);
1699 INIT_LIST_HEAD(&msc->iter_list);
1700
1701 msc->burst_len =
1702 (ioread32(msc->reg_base + REG_MSU_MSC0CTL) & MSC_LEN) >>
1703 __ffs(MSC_LEN);
1704
1705 return 0;
1706}
1707
1708static int msc_win_switch(struct msc *msc)
1709{
1710 struct msc_window *first;
1711
1712 if (list_empty(&msc->win_list))
1713 return -EINVAL;
1714
1715 first = list_first_entry(&msc->win_list, struct msc_window, entry);
1716
1717 if (msc_is_last_win(msc->cur_win))
1718 msc->cur_win = first;
1719 else
1720 msc->cur_win = list_next_entry(msc->cur_win, entry);
1721
1722 msc->base = msc_win_base(msc->cur_win);
1723 msc->base_addr = msc_win_base_dma(msc->cur_win);
1724
1725 intel_th_trace_switch(msc->thdev);
1726
1727 return 0;
1728}
1729
1730/**
1731 * intel_th_msc_window_unlock - put the window back in rotation
1732 * @dev: MSC device to which this relates
1733 * @sgt: buffer's sg_table for the window, does nothing if NULL
1734 */
1735void intel_th_msc_window_unlock(struct device *dev, struct sg_table *sgt)
1736{
1737 struct msc *msc = dev_get_drvdata(dev);
1738 struct msc_window *win;
1739
1740 if (!sgt)
1741 return;
1742
1743 win = msc_find_window(msc, sgt, false);
1744 if (!win)
1745 return;
1746
1747 msc_win_set_lockout(win, WIN_LOCKED, WIN_READY);
1748 if (msc->switch_on_unlock == win) {
1749 msc->switch_on_unlock = NULL;
1750 msc_win_switch(msc);
1751 }
1752}
1753EXPORT_SYMBOL_GPL(intel_th_msc_window_unlock);
1754
1755static void msc_work(struct work_struct *work)
1756{
1757 struct msc *msc = container_of(work, struct msc, work);
1758
1759 intel_th_msc_deactivate(msc->thdev);
1760}
1761
1762static irqreturn_t intel_th_msc_interrupt(struct intel_th_device *thdev)
1763{
1764 struct msc *msc = dev_get_drvdata(&thdev->dev);
1765 u32 msusts = ioread32(msc->msu_base + REG_MSU_MSUSTS);
1766 u32 mask = msc->index ? MSUSTS_MSC1BLAST : MSUSTS_MSC0BLAST;
1767 struct msc_window *win, *next_win;
1768
1769 if (!msc->do_irq || !msc->mbuf)
1770 return IRQ_NONE;
1771
1772 msusts &= mask;
1773
1774 if (!msusts)
1775 return msc->enabled ? IRQ_HANDLED : IRQ_NONE;
1776
1777 iowrite32(msusts, msc->msu_base + REG_MSU_MSUSTS);
1778
1779 if (!msc->enabled)
1780 return IRQ_NONE;
1781
1782 /* grab the window before we do the switch */
1783 win = msc->cur_win;
1784 if (!win)
1785 return IRQ_HANDLED;
1786 next_win = msc_next_window(win);
1787 if (!next_win)
1788 return IRQ_HANDLED;
1789
1790 /* next window: if READY, proceed, if LOCKED, stop the trace */
1791 if (msc_win_set_lockout(next_win, WIN_READY, WIN_INUSE)) {
1792 if (msc->stop_on_full)
1793 schedule_work(&msc->work);
1794 else
1795 msc->switch_on_unlock = next_win;
1796
1797 return IRQ_HANDLED;
1798 }
1799
1800 /* current window: INUSE -> LOCKED */
1801 msc_win_set_lockout(win, WIN_INUSE, WIN_LOCKED);
1802
1803 msc_win_switch(msc);
1804
1805 if (msc->mbuf && msc->mbuf->ready)
1806 msc->mbuf->ready(msc->mbuf_priv, win->sgt,
1807 msc_win_total_sz(win));
1808
1809 return IRQ_HANDLED;
1810}
1811
1812static const char * const msc_mode[] = {
1813 [MSC_MODE_SINGLE] = "single",
1814 [MSC_MODE_MULTI] = "multi",
1815 [MSC_MODE_EXI] = "ExI",
1816 [MSC_MODE_DEBUG] = "debug",
1817};
1818
1819static ssize_t
1820wrap_show(struct device *dev, struct device_attribute *attr, char *buf)
1821{
1822 struct msc *msc = dev_get_drvdata(dev);
1823
1824 return scnprintf(buf, PAGE_SIZE, "%d\n", msc->wrap);
1825}
1826
1827static ssize_t
1828wrap_store(struct device *dev, struct device_attribute *attr, const char *buf,
1829 size_t size)
1830{
1831 struct msc *msc = dev_get_drvdata(dev);
1832 unsigned long val;
1833 int ret;
1834
1835 ret = kstrtoul(buf, 10, &val);
1836 if (ret)
1837 return ret;
1838
1839 msc->wrap = !!val;
1840
1841 return size;
1842}
1843
1844static DEVICE_ATTR_RW(wrap);
1845
1846static void msc_buffer_unassign(struct msc *msc)
1847{
1848 lockdep_assert_held(&msc->buf_mutex);
1849
1850 if (!msc->mbuf)
1851 return;
1852
1853 msc->mbuf->unassign(msc->mbuf_priv);
1854 msu_buffer_put(msc->mbuf);
1855 msc->mbuf_priv = NULL;
1856 msc->mbuf = NULL;
1857}
1858
1859static ssize_t
1860mode_show(struct device *dev, struct device_attribute *attr, char *buf)
1861{
1862 struct msc *msc = dev_get_drvdata(dev);
1863 const char *mode = msc_mode[msc->mode];
1864 ssize_t ret;
1865
1866 mutex_lock(&msc->buf_mutex);
1867 if (msc->mbuf)
1868 mode = msc->mbuf->name;
1869 ret = scnprintf(buf, PAGE_SIZE, "%s\n", mode);
1870 mutex_unlock(&msc->buf_mutex);
1871
1872 return ret;
1873}
1874
1875static ssize_t
1876mode_store(struct device *dev, struct device_attribute *attr, const char *buf,
1877 size_t size)
1878{
1879 const struct msu_buffer *mbuf = NULL;
1880 struct msc *msc = dev_get_drvdata(dev);
1881 size_t len = size;
1882 char *cp, *mode;
1883 int i, ret;
1884
1885 if (!capable(CAP_SYS_RAWIO))
1886 return -EPERM;
1887
1888 cp = memchr(buf, '\n', len);
1889 if (cp)
1890 len = cp - buf;
1891
1892 mode = kstrndup(buf, len, GFP_KERNEL);
1893 if (!mode)
1894 return -ENOMEM;
1895
1896 i = match_string(msc_mode, ARRAY_SIZE(msc_mode), mode);
1897 if (i >= 0) {
1898 kfree(mode);
1899 goto found;
1900 }
1901
1902 /* Buffer sinks only work with a usable IRQ */
1903 if (!msc->do_irq) {
1904 kfree(mode);
1905 return -EINVAL;
1906 }
1907
1908 mbuf = msu_buffer_get(mode);
1909 kfree(mode);
1910 if (mbuf)
1911 goto found;
1912
1913 return -EINVAL;
1914
1915found:
1916 if (i == MSC_MODE_MULTI && msc->multi_is_broken)
1917 return -EOPNOTSUPP;
1918
1919 mutex_lock(&msc->buf_mutex);
1920 ret = 0;
1921
1922 /* Same buffer: do nothing */
1923 if (mbuf && mbuf == msc->mbuf) {
1924 /* put the extra reference we just got */
1925 msu_buffer_put(mbuf);
1926 goto unlock;
1927 }
1928
1929 ret = msc_buffer_unlocked_free_unless_used(msc);
1930 if (ret)
1931 goto unlock;
1932
1933 if (mbuf) {
1934 void *mbuf_priv = mbuf->assign(dev, &i);
1935
1936 if (!mbuf_priv) {
1937 ret = -ENOMEM;
1938 goto unlock;
1939 }
1940
1941 msc_buffer_unassign(msc);
1942 msc->mbuf_priv = mbuf_priv;
1943 msc->mbuf = mbuf;
1944 } else {
1945 msc_buffer_unassign(msc);
1946 }
1947
1948 msc->mode = i;
1949
1950unlock:
1951 if (ret && mbuf)
1952 msu_buffer_put(mbuf);
1953 mutex_unlock(&msc->buf_mutex);
1954
1955 return ret ? ret : size;
1956}
1957
1958static DEVICE_ATTR_RW(mode);
1959
1960static ssize_t
1961nr_pages_show(struct device *dev, struct device_attribute *attr, char *buf)
1962{
1963 struct msc *msc = dev_get_drvdata(dev);
1964 struct msc_window *win;
1965 size_t count = 0;
1966
1967 mutex_lock(&msc->buf_mutex);
1968
1969 if (msc->mode == MSC_MODE_SINGLE)
1970 count = scnprintf(buf, PAGE_SIZE, "%ld\n", msc->nr_pages);
1971 else if (msc->mode == MSC_MODE_MULTI) {
1972 list_for_each_entry(win, &msc->win_list, entry) {
1973 count += scnprintf(buf + count, PAGE_SIZE - count,
1974 "%d%c", win->nr_blocks,
1975 msc_is_last_win(win) ? '\n' : ',');
1976 }
1977 } else {
1978 count = scnprintf(buf, PAGE_SIZE, "unsupported\n");
1979 }
1980
1981 mutex_unlock(&msc->buf_mutex);
1982
1983 return count;
1984}
1985
1986static ssize_t
1987nr_pages_store(struct device *dev, struct device_attribute *attr,
1988 const char *buf, size_t size)
1989{
1990 struct msc *msc = dev_get_drvdata(dev);
1991 unsigned long val, *win = NULL, *rewin;
1992 size_t len = size;
1993 const char *p = buf;
1994 char *end, *s;
1995 int ret, nr_wins = 0;
1996
1997 if (!capable(CAP_SYS_RAWIO))
1998 return -EPERM;
1999
2000 ret = msc_buffer_free_unless_used(msc);
2001 if (ret)
2002 return ret;
2003
2004 /* scan the comma-separated list of allocation sizes */
2005 end = memchr(buf, '\n', len);
2006 if (end)
2007 len = end - buf;
2008
2009 do {
2010 end = memchr(p, ',', len);
2011 s = kstrndup(p, end ? end - p : len, GFP_KERNEL);
2012 if (!s) {
2013 ret = -ENOMEM;
2014 goto free_win;
2015 }
2016
2017 ret = kstrtoul(s, 10, &val);
2018 kfree(s);
2019
2020 if (ret || !val)
2021 goto free_win;
2022
2023 if (nr_wins && msc->mode == MSC_MODE_SINGLE) {
2024 ret = -EINVAL;
2025 goto free_win;
2026 }
2027
2028 nr_wins++;
2029 rewin = krealloc_array(win, nr_wins, sizeof(*win), GFP_KERNEL);
2030 if (!rewin) {
2031 kfree(win);
2032 return -ENOMEM;
2033 }
2034
2035 win = rewin;
2036 win[nr_wins - 1] = val;
2037
2038 if (!end)
2039 break;
2040
2041 /* consume the number and the following comma, hence +1 */
2042 len -= end - p + 1;
2043 p = end + 1;
2044 } while (len);
2045
2046 mutex_lock(&msc->buf_mutex);
2047 ret = msc_buffer_alloc(msc, win, nr_wins);
2048 mutex_unlock(&msc->buf_mutex);
2049
2050free_win:
2051 kfree(win);
2052
2053 return ret ? ret : size;
2054}
2055
2056static DEVICE_ATTR_RW(nr_pages);
2057
2058static ssize_t
2059win_switch_store(struct device *dev, struct device_attribute *attr,
2060 const char *buf, size_t size)
2061{
2062 struct msc *msc = dev_get_drvdata(dev);
2063 unsigned long val;
2064 int ret;
2065
2066 ret = kstrtoul(buf, 10, &val);
2067 if (ret)
2068 return ret;
2069
2070 if (val != 1)
2071 return -EINVAL;
2072
2073 ret = -EINVAL;
2074 mutex_lock(&msc->buf_mutex);
2075 /*
2076 * Window switch can only happen in the "multi" mode.
2077 * If a external buffer is engaged, they have the full
2078 * control over window switching.
2079 */
2080 if (msc->mode == MSC_MODE_MULTI && !msc->mbuf)
2081 ret = msc_win_switch(msc);
2082 mutex_unlock(&msc->buf_mutex);
2083
2084 return ret ? ret : size;
2085}
2086
2087static DEVICE_ATTR_WO(win_switch);
2088
2089static ssize_t stop_on_full_show(struct device *dev,
2090 struct device_attribute *attr, char *buf)
2091{
2092 struct msc *msc = dev_get_drvdata(dev);
2093
2094 return sprintf(buf, "%d\n", msc->stop_on_full);
2095}
2096
2097static ssize_t stop_on_full_store(struct device *dev,
2098 struct device_attribute *attr,
2099 const char *buf, size_t size)
2100{
2101 struct msc *msc = dev_get_drvdata(dev);
2102 int ret;
2103
2104 ret = kstrtobool(buf, &msc->stop_on_full);
2105 if (ret)
2106 return ret;
2107
2108 return size;
2109}
2110
2111static DEVICE_ATTR_RW(stop_on_full);
2112
2113static struct attribute *msc_output_attrs[] = {
2114 &dev_attr_wrap.attr,
2115 &dev_attr_mode.attr,
2116 &dev_attr_nr_pages.attr,
2117 &dev_attr_win_switch.attr,
2118 &dev_attr_stop_on_full.attr,
2119 NULL,
2120};
2121
2122static const struct attribute_group msc_output_group = {
2123 .attrs = msc_output_attrs,
2124};
2125
2126static int intel_th_msc_probe(struct intel_th_device *thdev)
2127{
2128 struct device *dev = &thdev->dev;
2129 struct resource *res;
2130 struct msc *msc;
2131 void __iomem *base;
2132 int err;
2133
2134 res = intel_th_device_get_resource(thdev, IORESOURCE_MEM, 0);
2135 if (!res)
2136 return -ENODEV;
2137
2138 base = devm_ioremap(dev, res->start, resource_size(res));
2139 if (!base)
2140 return -ENOMEM;
2141
2142 msc = devm_kzalloc(dev, sizeof(*msc), GFP_KERNEL);
2143 if (!msc)
2144 return -ENOMEM;
2145
2146 res = intel_th_device_get_resource(thdev, IORESOURCE_IRQ, 1);
2147 if (!res)
2148 msc->do_irq = 1;
2149
2150 if (INTEL_TH_CAP(to_intel_th(thdev), multi_is_broken))
2151 msc->multi_is_broken = 1;
2152
2153 msc->index = thdev->id;
2154
2155 msc->thdev = thdev;
2156 msc->reg_base = base + msc->index * 0x100;
2157 msc->msu_base = base;
2158
2159 INIT_WORK(&msc->work, msc_work);
2160 err = intel_th_msc_init(msc);
2161 if (err)
2162 return err;
2163
2164 dev_set_drvdata(dev, msc);
2165
2166 return 0;
2167}
2168
2169static void intel_th_msc_remove(struct intel_th_device *thdev)
2170{
2171 struct msc *msc = dev_get_drvdata(&thdev->dev);
2172 int ret;
2173
2174 intel_th_msc_deactivate(thdev);
2175
2176 /*
2177 * Buffers should not be used at this point except if the
2178 * output character device is still open and the parent
2179 * device gets detached from its bus, which is a FIXME.
2180 */
2181 ret = msc_buffer_free_unless_used(msc);
2182 WARN_ON_ONCE(ret);
2183}
2184
2185static struct intel_th_driver intel_th_msc_driver = {
2186 .probe = intel_th_msc_probe,
2187 .remove = intel_th_msc_remove,
2188 .irq = intel_th_msc_interrupt,
2189 .wait_empty = intel_th_msc_wait_empty,
2190 .activate = intel_th_msc_activate,
2191 .deactivate = intel_th_msc_deactivate,
2192 .fops = &intel_th_msc_fops,
2193 .attr_group = &msc_output_group,
2194 .driver = {
2195 .name = "msc",
2196 .owner = THIS_MODULE,
2197 },
2198};
2199
2200module_driver(intel_th_msc_driver,
2201 intel_th_driver_register,
2202 intel_th_driver_unregister);
2203
2204MODULE_LICENSE("GPL v2");
2205MODULE_DESCRIPTION("Intel(R) Trace Hub Memory Storage Unit driver");
2206MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@linux.intel.com>");