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