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  1/**************************************************************************
  2 *
  3 * Copyright © 2017 VMware, Inc., Palo Alto, CA., USA
  4 * All Rights Reserved.
  5 *
  6 * Permission is hereby granted, free of charge, to any person obtaining a
  7 * copy of this software and associated documentation files (the
  8 * "Software"), to deal in the Software without restriction, including
  9 * without limitation the rights to use, copy, modify, merge, publish,
 10 * distribute, sub license, and/or sell copies of the Software, and to
 11 * permit persons to whom the Software is furnished to do so, subject to
 12 * the following conditions:
 13 *
 14 * The above copyright notice and this permission notice (including the
 15 * next paragraph) shall be included in all copies or substantial portions
 16 * of the Software.
 17 *
 18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 19 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 20 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
 21 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
 22 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
 23 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 24 * USE OR OTHER DEALINGS IN THE SOFTWARE.
 25 *
 26 **************************************************************************/
 27
 28#include "vmwgfx_drv.h"
 29
 30/*
 31 * Template that implements find_first_diff() for a generic
 32 * unsigned integer type. @size and return value are in bytes.
 33 */
 34#define VMW_FIND_FIRST_DIFF(_type)			 \
 35static size_t vmw_find_first_diff_ ## _type		 \
 36	(const _type * dst, const _type * src, size_t size)\
 37{							 \
 38	size_t i;					 \
 39							 \
 40	for (i = 0; i < size; i += sizeof(_type)) {	 \
 41		if (*dst++ != *src++)			 \
 42			break;				 \
 43	}						 \
 44							 \
 45	return i;					 \
 46}
 47
 48
 49/*
 50 * Template that implements find_last_diff() for a generic
 51 * unsigned integer type. Pointers point to the item following the
 52 * *end* of the area to be examined. @size and return value are in
 53 * bytes.
 54 */
 55#define VMW_FIND_LAST_DIFF(_type)					\
 56static ssize_t vmw_find_last_diff_ ## _type(				\
 57	const _type * dst, const _type * src, size_t size)		\
 58{									\
 59	while (size) {							\
 60		if (*--dst != *--src)					\
 61			break;						\
 62									\
 63		size -= sizeof(_type);					\
 64	}								\
 65	return size;							\
 66}
 67
 68
 69/*
 70 * Instantiate find diff functions for relevant unsigned integer sizes,
 71 * assuming that wider integers are faster (including aligning) up to the
 72 * architecture native width, which is assumed to be 32 bit unless
 73 * CONFIG_64BIT is defined.
 74 */
 75VMW_FIND_FIRST_DIFF(u8);
 76VMW_FIND_LAST_DIFF(u8);
 77
 78VMW_FIND_FIRST_DIFF(u16);
 79VMW_FIND_LAST_DIFF(u16);
 80
 81VMW_FIND_FIRST_DIFF(u32);
 82VMW_FIND_LAST_DIFF(u32);
 83
 84#ifdef CONFIG_64BIT
 85VMW_FIND_FIRST_DIFF(u64);
 86VMW_FIND_LAST_DIFF(u64);
 87#endif
 88
 89
 90/* We use size aligned copies. This computes (addr - align(addr)) */
 91#define SPILL(_var, _type) ((unsigned long) _var & (sizeof(_type) - 1))
 92
 93
 94/*
 95 * Template to compute find_first_diff() for a certain integer type
 96 * including a head copy for alignment, and adjustment of parameters
 97 * for tail find or increased resolution find using an unsigned integer find
 98 * of smaller width. If finding is complete, and resolution is sufficient,
 99 * the macro executes a return statement. Otherwise it falls through.
100 */
101#define VMW_TRY_FIND_FIRST_DIFF(_type)					\
102do {									\
103	unsigned int spill = SPILL(dst, _type);				\
104	size_t diff_offs;						\
105									\
106	if (spill && spill == SPILL(src, _type) &&			\
107	    sizeof(_type) - spill <= size) {				\
108		spill = sizeof(_type) - spill;				\
109		diff_offs = vmw_find_first_diff_u8(dst, src, spill);	\
110		if (diff_offs < spill)					\
111			return round_down(offset + diff_offs, granularity); \
112									\
113		dst += spill;						\
114		src += spill;						\
115		size -= spill;						\
116		offset += spill;					\
117		spill = 0;						\
118	}								\
119	if (!spill && !SPILL(src, _type)) {				\
120		size_t to_copy = size &	 ~(sizeof(_type) - 1);		\
121									\
122		diff_offs = vmw_find_first_diff_ ## _type		\
123			((_type *) dst, (_type *) src, to_copy);	\
124		if (diff_offs >= size || granularity == sizeof(_type))	\
125			return (offset + diff_offs);			\
126									\
127		dst += diff_offs;					\
128		src += diff_offs;					\
129		size -= diff_offs;					\
130		offset += diff_offs;					\
131	}								\
132} while (0)								\
133
134
135/**
136 * vmw_find_first_diff - find the first difference between dst and src
137 *
138 * @dst: The destination address
139 * @src: The source address
140 * @size: Number of bytes to compare
141 * @granularity: The granularity needed for the return value in bytes.
142 * return: The offset from find start where the first difference was
143 * encountered in bytes. If no difference was found, the function returns
144 * a value >= @size.
145 */
146static size_t vmw_find_first_diff(const u8 *dst, const u8 *src, size_t size,
147				  size_t granularity)
148{
149	size_t offset = 0;
150
151	/*
152	 * Try finding with large integers if alignment allows, or we can
153	 * fix it. Fall through if we need better resolution or alignment
154	 * was bad.
155	 */
156#ifdef CONFIG_64BIT
157	VMW_TRY_FIND_FIRST_DIFF(u64);
158#endif
159	VMW_TRY_FIND_FIRST_DIFF(u32);
160	VMW_TRY_FIND_FIRST_DIFF(u16);
161
162	return round_down(offset + vmw_find_first_diff_u8(dst, src, size),
163			  granularity);
164}
165
166
167/*
168 * Template to compute find_last_diff() for a certain integer type
169 * including a tail copy for alignment, and adjustment of parameters
170 * for head find or increased resolution find using an unsigned integer find
171 * of smaller width. If finding is complete, and resolution is sufficient,
172 * the macro executes a return statement. Otherwise it falls through.
173 */
174#define VMW_TRY_FIND_LAST_DIFF(_type)					\
175do {									\
176	unsigned int spill = SPILL(dst, _type);				\
177	ssize_t location;						\
178	ssize_t diff_offs;						\
179									\
180	if (spill && spill <= size && spill == SPILL(src, _type)) {	\
181		diff_offs = vmw_find_last_diff_u8(dst, src, spill);	\
182		if (diff_offs) {					\
183			location = size - spill + diff_offs - 1;	\
184			return round_down(location, granularity);	\
185		}							\
186									\
187		dst -= spill;						\
188		src -= spill;						\
189		size -= spill;						\
190		spill = 0;						\
191	}								\
192	if (!spill && !SPILL(src, _type)) {				\
193		size_t to_copy = round_down(size, sizeof(_type));	\
194									\
195		diff_offs = vmw_find_last_diff_ ## _type		\
196			((_type *) dst, (_type *) src, to_copy);	\
197		location = size - to_copy + diff_offs - sizeof(_type);	\
198		if (location < 0 || granularity == sizeof(_type))	\
199			return location;				\
200									\
201		dst -= to_copy - diff_offs;				\
202		src -= to_copy - diff_offs;				\
203		size -= to_copy - diff_offs;				\
204	}								\
205} while (0)
206
207
208/**
209 * vmw_find_last_diff - find the last difference between dst and src
210 *
211 * @dst: The destination address
212 * @src: The source address
213 * @size: Number of bytes to compare
214 * @granularity: The granularity needed for the return value in bytes.
215 * return: The offset from find start where the last difference was
216 * encountered in bytes, or a negative value if no difference was found.
217 */
218static ssize_t vmw_find_last_diff(const u8 *dst, const u8 *src, size_t size,
219				  size_t granularity)
220{
221	dst += size;
222	src += size;
223
224#ifdef CONFIG_64BIT
225	VMW_TRY_FIND_LAST_DIFF(u64);
226#endif
227	VMW_TRY_FIND_LAST_DIFF(u32);
228	VMW_TRY_FIND_LAST_DIFF(u16);
229
230	return round_down(vmw_find_last_diff_u8(dst, src, size) - 1,
231			  granularity);
232}
233
234
235/**
236 * vmw_memcpy - A wrapper around kernel memcpy with allowing to plug it into a
237 * struct vmw_diff_cpy.
238 *
239 * @diff: The struct vmw_diff_cpy closure argument (unused).
240 * @dest: The copy destination.
241 * @src: The copy source.
242 * @n: Number of bytes to copy.
243 */
244void vmw_memcpy(struct vmw_diff_cpy *diff, u8 *dest, const u8 *src, size_t n)
245{
246	memcpy(dest, src, n);
247}
248
249
250/**
251 * vmw_adjust_rect - Adjust rectangle coordinates for newly found difference
252 *
253 * @diff: The struct vmw_diff_cpy used to track the modified bounding box.
254 * @diff_offs: The offset from @diff->line_offset where the difference was
255 * found.
256 */
257static void vmw_adjust_rect(struct vmw_diff_cpy *diff, size_t diff_offs)
258{
259	size_t offs = (diff_offs + diff->line_offset) / diff->cpp;
260	struct drm_rect *rect = &diff->rect;
261
262	rect->x1 = min_t(int, rect->x1, offs);
263	rect->x2 = max_t(int, rect->x2, offs + 1);
264	rect->y1 = min_t(int, rect->y1, diff->line);
265	rect->y2 = max_t(int, rect->y2, diff->line + 1);
266}
267
268/**
269 * vmw_diff_memcpy - memcpy that creates a bounding box of modified content.
270 *
271 * @diff: The struct vmw_diff_cpy used to track the modified bounding box.
272 * @dest: The copy destination.
273 * @src: The copy source.
274 * @n: Number of bytes to copy.
275 *
276 * In order to correctly track the modified content, the field @diff->line must
277 * be pre-loaded with the current line number, the field @diff->line_offset must
278 * be pre-loaded with the line offset in bytes where the copy starts, and
279 * finally the field @diff->cpp need to be preloaded with the number of bytes
280 * per unit in the horizontal direction of the area we're examining.
281 * Typically bytes per pixel.
282 * This is needed to know the needed granularity of the difference computing
283 * operations. A higher cpp generally leads to faster execution at the cost of
284 * bounding box width precision.
285 */
286void vmw_diff_memcpy(struct vmw_diff_cpy *diff, u8 *dest, const u8 *src,
287		     size_t n)
288{
289	ssize_t csize, byte_len;
290
291	if (WARN_ON_ONCE(round_down(n, diff->cpp) != n))
292		return;
293
294	/* TODO: Possibly use a single vmw_find_first_diff per line? */
295	csize = vmw_find_first_diff(dest, src, n, diff->cpp);
296	if (csize < n) {
297		vmw_adjust_rect(diff, csize);
298		byte_len = diff->cpp;
299
300		/*
301		 * Starting from where first difference was found, find
302		 * location of last difference, and then copy.
303		 */
304		diff->line_offset += csize;
305		dest += csize;
306		src += csize;
307		n -= csize;
308		csize = vmw_find_last_diff(dest, src, n, diff->cpp);
309		if (csize >= 0) {
310			byte_len += csize;
311			vmw_adjust_rect(diff, csize);
312		}
313		memcpy(dest, src, byte_len);
314	}
315	diff->line_offset += n;
316}
317
318/**
319 * struct vmw_bo_blit_line_data - Convenience argument to vmw_bo_cpu_blit_line
320 *
321 * @mapped_dst: Already mapped destination page index in @dst_pages.
322 * @dst_addr: Kernel virtual address of mapped destination page.
323 * @dst_pages: Array of destination bo pages.
324 * @dst_num_pages: Number of destination bo pages.
325 * @dst_prot: Destination bo page protection.
326 * @mapped_src: Already mapped source page index in @dst_pages.
327 * @src_addr: Kernel virtual address of mapped source page.
328 * @src_pages: Array of source bo pages.
329 * @src_num_pages: Number of source bo pages.
330 * @src_prot: Source bo page protection.
331 * @diff: Struct vmw_diff_cpy, in the end forwarded to the memcpy routine.
332 */
333struct vmw_bo_blit_line_data {
334	u32 mapped_dst;
335	u8 *dst_addr;
336	struct page **dst_pages;
337	u32 dst_num_pages;
338	pgprot_t dst_prot;
339	u32 mapped_src;
340	u8 *src_addr;
341	struct page **src_pages;
342	u32 src_num_pages;
343	pgprot_t src_prot;
344	struct vmw_diff_cpy *diff;
345};
346
347/**
348 * vmw_bo_cpu_blit_line - Blit part of a line from one bo to another.
349 *
350 * @d: Blit data as described above.
351 * @dst_offset: Destination copy start offset from start of bo.
352 * @src_offset: Source copy start offset from start of bo.
353 * @bytes_to_copy: Number of bytes to copy in this line.
354 */
355static int vmw_bo_cpu_blit_line(struct vmw_bo_blit_line_data *d,
356				u32 dst_offset,
357				u32 src_offset,
358				u32 bytes_to_copy)
359{
360	struct vmw_diff_cpy *diff = d->diff;
361
362	while (bytes_to_copy) {
363		u32 copy_size = bytes_to_copy;
364		u32 dst_page = dst_offset >> PAGE_SHIFT;
365		u32 src_page = src_offset >> PAGE_SHIFT;
366		u32 dst_page_offset = dst_offset & ~PAGE_MASK;
367		u32 src_page_offset = src_offset & ~PAGE_MASK;
368		bool unmap_dst = d->dst_addr && dst_page != d->mapped_dst;
369		bool unmap_src = d->src_addr && (src_page != d->mapped_src ||
370						 unmap_dst);
371
372		copy_size = min_t(u32, copy_size, PAGE_SIZE - dst_page_offset);
373		copy_size = min_t(u32, copy_size, PAGE_SIZE - src_page_offset);
374
375		if (unmap_src) {
376			ttm_kunmap_atomic_prot(d->src_addr, d->src_prot);
377			d->src_addr = NULL;
378		}
379
380		if (unmap_dst) {
381			ttm_kunmap_atomic_prot(d->dst_addr, d->dst_prot);
382			d->dst_addr = NULL;
383		}
384
385		if (!d->dst_addr) {
386			if (WARN_ON_ONCE(dst_page >= d->dst_num_pages))
387				return -EINVAL;
388
389			d->dst_addr =
390				ttm_kmap_atomic_prot(d->dst_pages[dst_page],
391						     d->dst_prot);
392			if (!d->dst_addr)
393				return -ENOMEM;
394
395			d->mapped_dst = dst_page;
396		}
397
398		if (!d->src_addr) {
399			if (WARN_ON_ONCE(src_page >= d->src_num_pages))
400				return -EINVAL;
401
402			d->src_addr =
403				ttm_kmap_atomic_prot(d->src_pages[src_page],
404						     d->src_prot);
405			if (!d->src_addr)
406				return -ENOMEM;
407
408			d->mapped_src = src_page;
409		}
410		diff->do_cpy(diff, d->dst_addr + dst_page_offset,
411			     d->src_addr + src_page_offset, copy_size);
412
413		bytes_to_copy -= copy_size;
414		dst_offset += copy_size;
415		src_offset += copy_size;
416	}
417
418	return 0;
419}
420
421/**
422 * ttm_bo_cpu_blit - in-kernel cpu blit.
423 *
424 * @dst: Destination buffer object.
425 * @dst_offset: Destination offset of blit start in bytes.
426 * @dst_stride: Destination stride in bytes.
427 * @src: Source buffer object.
428 * @src_offset: Source offset of blit start in bytes.
429 * @src_stride: Source stride in bytes.
430 * @w: Width of blit.
431 * @h: Height of blit.
432 * return: Zero on success. Negative error value on failure. Will print out
433 * kernel warnings on caller bugs.
434 *
435 * Performs a CPU blit from one buffer object to another avoiding a full
436 * bo vmap which may exhaust- or fragment vmalloc space.
437 * On supported architectures (x86), we're using kmap_atomic which avoids
438 * cross-processor TLB- and cache flushes and may, on non-HIGHMEM systems
439 * reference already set-up mappings.
440 *
441 * Neither of the buffer objects may be placed in PCI memory
442 * (Fixed memory in TTM terminology) when using this function.
443 */
444int vmw_bo_cpu_blit(struct ttm_buffer_object *dst,
445		    u32 dst_offset, u32 dst_stride,
446		    struct ttm_buffer_object *src,
447		    u32 src_offset, u32 src_stride,
448		    u32 w, u32 h,
449		    struct vmw_diff_cpy *diff)
450{
451	struct ttm_operation_ctx ctx = {
452		.interruptible = false,
453		.no_wait_gpu = false
454	};
455	u32 j, initial_line = dst_offset / dst_stride;
456	struct vmw_bo_blit_line_data d;
457	int ret = 0;
458
459	/* Buffer objects need to be either pinned or reserved: */
460	if (!(dst->mem.placement & TTM_PL_FLAG_NO_EVICT))
461		lockdep_assert_held(&dst->resv->lock.base);
462	if (!(src->mem.placement & TTM_PL_FLAG_NO_EVICT))
463		lockdep_assert_held(&src->resv->lock.base);
464
465	if (dst->ttm->state == tt_unpopulated) {
466		ret = dst->ttm->bdev->driver->ttm_tt_populate(dst->ttm, &ctx);
467		if (ret)
468			return ret;
469	}
470
471	if (src->ttm->state == tt_unpopulated) {
472		ret = src->ttm->bdev->driver->ttm_tt_populate(src->ttm, &ctx);
473		if (ret)
474			return ret;
475	}
476
477	d.mapped_dst = 0;
478	d.mapped_src = 0;
479	d.dst_addr = NULL;
480	d.src_addr = NULL;
481	d.dst_pages = dst->ttm->pages;
482	d.src_pages = src->ttm->pages;
483	d.dst_num_pages = dst->num_pages;
484	d.src_num_pages = src->num_pages;
485	d.dst_prot = ttm_io_prot(dst->mem.placement, PAGE_KERNEL);
486	d.src_prot = ttm_io_prot(src->mem.placement, PAGE_KERNEL);
487	d.diff = diff;
488
489	for (j = 0; j < h; ++j) {
490		diff->line = j + initial_line;
491		diff->line_offset = dst_offset % dst_stride;
492		ret = vmw_bo_cpu_blit_line(&d, dst_offset, src_offset, w);
493		if (ret)
494			goto out;
495
496		dst_offset += dst_stride;
497		src_offset += src_stride;
498	}
499out:
500	if (d.src_addr)
501		ttm_kunmap_atomic_prot(d.src_addr, d.src_prot);
502	if (d.dst_addr)
503		ttm_kunmap_atomic_prot(d.dst_addr, d.dst_prot);
504
505	return ret;
506}