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