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