xref: /kernel/linux/linux-5.10/arch/mips/mm/page.c (revision 8c2ecf20)
1/*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License.  See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * Copyright (C) 2003, 04, 05 Ralf Baechle (ralf@linux-mips.org)
7 * Copyright (C) 2007  Maciej W. Rozycki
8 * Copyright (C) 2008  Thiemo Seufer
9 * Copyright (C) 2012  MIPS Technologies, Inc.
10 */
11#include <linux/kernel.h>
12#include <linux/sched.h>
13#include <linux/smp.h>
14#include <linux/mm.h>
15#include <linux/proc_fs.h>
16
17#include <asm/bugs.h>
18#include <asm/cacheops.h>
19#include <asm/cpu-type.h>
20#include <asm/inst.h>
21#include <asm/io.h>
22#include <asm/page.h>
23#include <asm/prefetch.h>
24#include <asm/bootinfo.h>
25#include <asm/mipsregs.h>
26#include <asm/mmu_context.h>
27#include <asm/cpu.h>
28#include <asm/war.h>
29
30#ifdef CONFIG_SIBYTE_DMA_PAGEOPS
31#include <asm/sibyte/sb1250.h>
32#include <asm/sibyte/sb1250_regs.h>
33#include <asm/sibyte/sb1250_dma.h>
34#endif
35
36#include <asm/uasm.h>
37
38/* Registers used in the assembled routines. */
39#define ZERO 0
40#define AT 2
41#define A0 4
42#define A1 5
43#define A2 6
44#define T0 8
45#define T1 9
46#define T2 10
47#define T3 11
48#define T9 25
49#define RA 31
50
51/* Handle labels (which must be positive integers). */
52enum label_id {
53	label_clear_nopref = 1,
54	label_clear_pref,
55	label_copy_nopref,
56	label_copy_pref_both,
57	label_copy_pref_store,
58};
59
60UASM_L_LA(_clear_nopref)
61UASM_L_LA(_clear_pref)
62UASM_L_LA(_copy_nopref)
63UASM_L_LA(_copy_pref_both)
64UASM_L_LA(_copy_pref_store)
65
66/* We need one branch and therefore one relocation per target label. */
67static struct uasm_label labels[5];
68static struct uasm_reloc relocs[5];
69
70#define cpu_is_r4600_v1_x()	((read_c0_prid() & 0xfffffff0) == 0x00002010)
71#define cpu_is_r4600_v2_x()	((read_c0_prid() & 0xfffffff0) == 0x00002020)
72
73/*
74 * R6 has a limited offset of the pref instruction.
75 * Skip it if the offset is more than 9 bits.
76 */
77#define _uasm_i_pref(a, b, c, d)		\
78do {						\
79	if (cpu_has_mips_r6) {			\
80		if (c <= 0xff && c >= -0x100)	\
81			uasm_i_pref(a, b, c, d);\
82	} else {				\
83		uasm_i_pref(a, b, c, d);	\
84	}					\
85} while(0)
86
87static int pref_bias_clear_store;
88static int pref_bias_copy_load;
89static int pref_bias_copy_store;
90
91static u32 pref_src_mode;
92static u32 pref_dst_mode;
93
94static int clear_word_size;
95static int copy_word_size;
96
97static int half_clear_loop_size;
98static int half_copy_loop_size;
99
100static int cache_line_size;
101#define cache_line_mask() (cache_line_size - 1)
102
103static inline void
104pg_addiu(u32 **buf, unsigned int reg1, unsigned int reg2, unsigned int off)
105{
106	if (cpu_has_64bit_gp_regs && DADDI_WAR && r4k_daddiu_bug()) {
107		if (off > 0x7fff) {
108			uasm_i_lui(buf, T9, uasm_rel_hi(off));
109			uasm_i_addiu(buf, T9, T9, uasm_rel_lo(off));
110		} else
111			uasm_i_addiu(buf, T9, ZERO, off);
112		uasm_i_daddu(buf, reg1, reg2, T9);
113	} else {
114		if (off > 0x7fff) {
115			uasm_i_lui(buf, T9, uasm_rel_hi(off));
116			uasm_i_addiu(buf, T9, T9, uasm_rel_lo(off));
117			UASM_i_ADDU(buf, reg1, reg2, T9);
118		} else
119			UASM_i_ADDIU(buf, reg1, reg2, off);
120	}
121}
122
123static void set_prefetch_parameters(void)
124{
125	if (cpu_has_64bit_gp_regs || cpu_has_64bit_zero_reg)
126		clear_word_size = 8;
127	else
128		clear_word_size = 4;
129
130	if (cpu_has_64bit_gp_regs)
131		copy_word_size = 8;
132	else
133		copy_word_size = 4;
134
135	/*
136	 * The pref's used here are using "streaming" hints, which cause the
137	 * copied data to be kicked out of the cache sooner.  A page copy often
138	 * ends up copying a lot more data than is commonly used, so this seems
139	 * to make sense in terms of reducing cache pollution, but I've no real
140	 * performance data to back this up.
141	 */
142	if (cpu_has_prefetch) {
143		/*
144		 * XXX: Most prefetch bias values in here are based on
145		 * guesswork.
146		 */
147		cache_line_size = cpu_dcache_line_size();
148		switch (current_cpu_type()) {
149		case CPU_R5500:
150		case CPU_TX49XX:
151			/* These processors only support the Pref_Load. */
152			pref_bias_copy_load = 256;
153			break;
154
155		case CPU_R10000:
156		case CPU_R12000:
157		case CPU_R14000:
158		case CPU_R16000:
159			/*
160			 * Those values have been experimentally tuned for an
161			 * Origin 200.
162			 */
163			pref_bias_clear_store = 512;
164			pref_bias_copy_load = 256;
165			pref_bias_copy_store = 256;
166			pref_src_mode = Pref_LoadStreamed;
167			pref_dst_mode = Pref_StoreStreamed;
168			break;
169
170		case CPU_SB1:
171		case CPU_SB1A:
172			pref_bias_clear_store = 128;
173			pref_bias_copy_load = 128;
174			pref_bias_copy_store = 128;
175			/*
176			 * SB1 pass1 Pref_LoadStreamed/Pref_StoreStreamed
177			 * hints are broken.
178			 */
179			if (current_cpu_type() == CPU_SB1 &&
180			    (current_cpu_data.processor_id & 0xff) < 0x02) {
181				pref_src_mode = Pref_Load;
182				pref_dst_mode = Pref_Store;
183			} else {
184				pref_src_mode = Pref_LoadStreamed;
185				pref_dst_mode = Pref_StoreStreamed;
186			}
187			break;
188
189		case CPU_LOONGSON64:
190			/* Loongson-3 only support the Pref_Load/Pref_Store. */
191			pref_bias_clear_store = 128;
192			pref_bias_copy_load = 128;
193			pref_bias_copy_store = 128;
194			pref_src_mode = Pref_Load;
195			pref_dst_mode = Pref_Store;
196			break;
197
198		default:
199			pref_bias_clear_store = 128;
200			pref_bias_copy_load = 256;
201			pref_bias_copy_store = 128;
202			pref_src_mode = Pref_LoadStreamed;
203			if (cpu_has_mips_r6)
204				/*
205				 * Bit 30 (Pref_PrepareForStore) has been
206				 * removed from MIPS R6. Use bit 5
207				 * (Pref_StoreStreamed).
208				 */
209				pref_dst_mode = Pref_StoreStreamed;
210			else
211				pref_dst_mode = Pref_PrepareForStore;
212			break;
213		}
214	} else {
215		if (cpu_has_cache_cdex_s)
216			cache_line_size = cpu_scache_line_size();
217		else if (cpu_has_cache_cdex_p)
218			cache_line_size = cpu_dcache_line_size();
219	}
220	/*
221	 * Too much unrolling will overflow the available space in
222	 * clear_space_array / copy_page_array.
223	 */
224	half_clear_loop_size = min(16 * clear_word_size,
225				   max(cache_line_size >> 1,
226				       4 * clear_word_size));
227	half_copy_loop_size = min(16 * copy_word_size,
228				  max(cache_line_size >> 1,
229				      4 * copy_word_size));
230}
231
232static void build_clear_store(u32 **buf, int off)
233{
234	if (cpu_has_64bit_gp_regs || cpu_has_64bit_zero_reg) {
235		uasm_i_sd(buf, ZERO, off, A0);
236	} else {
237		uasm_i_sw(buf, ZERO, off, A0);
238	}
239}
240
241static inline void build_clear_pref(u32 **buf, int off)
242{
243	if (off & cache_line_mask())
244		return;
245
246	if (pref_bias_clear_store) {
247		_uasm_i_pref(buf, pref_dst_mode, pref_bias_clear_store + off,
248			    A0);
249	} else if (cache_line_size == (half_clear_loop_size << 1)) {
250		if (cpu_has_cache_cdex_s) {
251			uasm_i_cache(buf, Create_Dirty_Excl_SD, off, A0);
252		} else if (cpu_has_cache_cdex_p) {
253			if (IS_ENABLED(CONFIG_WAR_R4600_V1_HIT_CACHEOP) &&
254			    cpu_is_r4600_v1_x()) {
255				uasm_i_nop(buf);
256				uasm_i_nop(buf);
257				uasm_i_nop(buf);
258				uasm_i_nop(buf);
259			}
260
261			if (IS_ENABLED(CONFIG_WAR_R4600_V2_HIT_CACHEOP) &&
262			    cpu_is_r4600_v2_x())
263				uasm_i_lw(buf, ZERO, ZERO, AT);
264
265			uasm_i_cache(buf, Create_Dirty_Excl_D, off, A0);
266		}
267	}
268}
269
270extern u32 __clear_page_start;
271extern u32 __clear_page_end;
272extern u32 __copy_page_start;
273extern u32 __copy_page_end;
274
275void build_clear_page(void)
276{
277	int off;
278	u32 *buf = &__clear_page_start;
279	struct uasm_label *l = labels;
280	struct uasm_reloc *r = relocs;
281	int i;
282	static atomic_t run_once = ATOMIC_INIT(0);
283
284	if (atomic_xchg(&run_once, 1)) {
285		return;
286	}
287
288	memset(labels, 0, sizeof(labels));
289	memset(relocs, 0, sizeof(relocs));
290
291	set_prefetch_parameters();
292
293	/*
294	 * This algorithm makes the following assumptions:
295	 *   - The prefetch bias is a multiple of 2 words.
296	 *   - The prefetch bias is less than one page.
297	 */
298	BUG_ON(pref_bias_clear_store % (2 * clear_word_size));
299	BUG_ON(PAGE_SIZE < pref_bias_clear_store);
300
301	off = PAGE_SIZE - pref_bias_clear_store;
302	if (off > 0xffff || !pref_bias_clear_store)
303		pg_addiu(&buf, A2, A0, off);
304	else
305		uasm_i_ori(&buf, A2, A0, off);
306
307	if (IS_ENABLED(CONFIG_WAR_R4600_V2_HIT_CACHEOP) && cpu_is_r4600_v2_x())
308		uasm_i_lui(&buf, AT, uasm_rel_hi(0xa0000000));
309
310	off = cache_line_size ? min(8, pref_bias_clear_store / cache_line_size)
311				* cache_line_size : 0;
312	while (off) {
313		build_clear_pref(&buf, -off);
314		off -= cache_line_size;
315	}
316	uasm_l_clear_pref(&l, buf);
317	do {
318		build_clear_pref(&buf, off);
319		build_clear_store(&buf, off);
320		off += clear_word_size;
321	} while (off < half_clear_loop_size);
322	pg_addiu(&buf, A0, A0, 2 * off);
323	off = -off;
324	do {
325		build_clear_pref(&buf, off);
326		if (off == -clear_word_size)
327			uasm_il_bne(&buf, &r, A0, A2, label_clear_pref);
328		build_clear_store(&buf, off);
329		off += clear_word_size;
330	} while (off < 0);
331
332	if (pref_bias_clear_store) {
333		pg_addiu(&buf, A2, A0, pref_bias_clear_store);
334		uasm_l_clear_nopref(&l, buf);
335		off = 0;
336		do {
337			build_clear_store(&buf, off);
338			off += clear_word_size;
339		} while (off < half_clear_loop_size);
340		pg_addiu(&buf, A0, A0, 2 * off);
341		off = -off;
342		do {
343			if (off == -clear_word_size)
344				uasm_il_bne(&buf, &r, A0, A2,
345					    label_clear_nopref);
346			build_clear_store(&buf, off);
347			off += clear_word_size;
348		} while (off < 0);
349	}
350
351	uasm_i_jr(&buf, RA);
352	uasm_i_nop(&buf);
353
354	BUG_ON(buf > &__clear_page_end);
355
356	uasm_resolve_relocs(relocs, labels);
357
358	pr_debug("Synthesized clear page handler (%u instructions).\n",
359		 (u32)(buf - &__clear_page_start));
360
361	pr_debug("\t.set push\n");
362	pr_debug("\t.set noreorder\n");
363	for (i = 0; i < (buf - &__clear_page_start); i++)
364		pr_debug("\t.word 0x%08x\n", (&__clear_page_start)[i]);
365	pr_debug("\t.set pop\n");
366}
367
368static void build_copy_load(u32 **buf, int reg, int off)
369{
370	if (cpu_has_64bit_gp_regs) {
371		uasm_i_ld(buf, reg, off, A1);
372	} else {
373		uasm_i_lw(buf, reg, off, A1);
374	}
375}
376
377static void build_copy_store(u32 **buf, int reg, int off)
378{
379	if (cpu_has_64bit_gp_regs) {
380		uasm_i_sd(buf, reg, off, A0);
381	} else {
382		uasm_i_sw(buf, reg, off, A0);
383	}
384}
385
386static inline void build_copy_load_pref(u32 **buf, int off)
387{
388	if (off & cache_line_mask())
389		return;
390
391	if (pref_bias_copy_load)
392		_uasm_i_pref(buf, pref_src_mode, pref_bias_copy_load + off, A1);
393}
394
395static inline void build_copy_store_pref(u32 **buf, int off)
396{
397	if (off & cache_line_mask())
398		return;
399
400	if (pref_bias_copy_store) {
401		_uasm_i_pref(buf, pref_dst_mode, pref_bias_copy_store + off,
402			    A0);
403	} else if (cache_line_size == (half_copy_loop_size << 1)) {
404		if (cpu_has_cache_cdex_s) {
405			uasm_i_cache(buf, Create_Dirty_Excl_SD, off, A0);
406		} else if (cpu_has_cache_cdex_p) {
407			if (IS_ENABLED(CONFIG_WAR_R4600_V1_HIT_CACHEOP) &&
408			    cpu_is_r4600_v1_x()) {
409				uasm_i_nop(buf);
410				uasm_i_nop(buf);
411				uasm_i_nop(buf);
412				uasm_i_nop(buf);
413			}
414
415			if (IS_ENABLED(CONFIG_WAR_R4600_V2_HIT_CACHEOP) &&
416			    cpu_is_r4600_v2_x())
417				uasm_i_lw(buf, ZERO, ZERO, AT);
418
419			uasm_i_cache(buf, Create_Dirty_Excl_D, off, A0);
420		}
421	}
422}
423
424void build_copy_page(void)
425{
426	int off;
427	u32 *buf = &__copy_page_start;
428	struct uasm_label *l = labels;
429	struct uasm_reloc *r = relocs;
430	int i;
431	static atomic_t run_once = ATOMIC_INIT(0);
432
433	if (atomic_xchg(&run_once, 1)) {
434		return;
435	}
436
437	memset(labels, 0, sizeof(labels));
438	memset(relocs, 0, sizeof(relocs));
439
440	set_prefetch_parameters();
441
442	/*
443	 * This algorithm makes the following assumptions:
444	 *   - All prefetch biases are multiples of 8 words.
445	 *   - The prefetch biases are less than one page.
446	 *   - The store prefetch bias isn't greater than the load
447	 *     prefetch bias.
448	 */
449	BUG_ON(pref_bias_copy_load % (8 * copy_word_size));
450	BUG_ON(pref_bias_copy_store % (8 * copy_word_size));
451	BUG_ON(PAGE_SIZE < pref_bias_copy_load);
452	BUG_ON(pref_bias_copy_store > pref_bias_copy_load);
453
454	off = PAGE_SIZE - pref_bias_copy_load;
455	if (off > 0xffff || !pref_bias_copy_load)
456		pg_addiu(&buf, A2, A0, off);
457	else
458		uasm_i_ori(&buf, A2, A0, off);
459
460	if (IS_ENABLED(CONFIG_WAR_R4600_V2_HIT_CACHEOP) && cpu_is_r4600_v2_x())
461		uasm_i_lui(&buf, AT, uasm_rel_hi(0xa0000000));
462
463	off = cache_line_size ? min(8, pref_bias_copy_load / cache_line_size) *
464				cache_line_size : 0;
465	while (off) {
466		build_copy_load_pref(&buf, -off);
467		off -= cache_line_size;
468	}
469	off = cache_line_size ? min(8, pref_bias_copy_store / cache_line_size) *
470				cache_line_size : 0;
471	while (off) {
472		build_copy_store_pref(&buf, -off);
473		off -= cache_line_size;
474	}
475	uasm_l_copy_pref_both(&l, buf);
476	do {
477		build_copy_load_pref(&buf, off);
478		build_copy_load(&buf, T0, off);
479		build_copy_load_pref(&buf, off + copy_word_size);
480		build_copy_load(&buf, T1, off + copy_word_size);
481		build_copy_load_pref(&buf, off + 2 * copy_word_size);
482		build_copy_load(&buf, T2, off + 2 * copy_word_size);
483		build_copy_load_pref(&buf, off + 3 * copy_word_size);
484		build_copy_load(&buf, T3, off + 3 * copy_word_size);
485		build_copy_store_pref(&buf, off);
486		build_copy_store(&buf, T0, off);
487		build_copy_store_pref(&buf, off + copy_word_size);
488		build_copy_store(&buf, T1, off + copy_word_size);
489		build_copy_store_pref(&buf, off + 2 * copy_word_size);
490		build_copy_store(&buf, T2, off + 2 * copy_word_size);
491		build_copy_store_pref(&buf, off + 3 * copy_word_size);
492		build_copy_store(&buf, T3, off + 3 * copy_word_size);
493		off += 4 * copy_word_size;
494	} while (off < half_copy_loop_size);
495	pg_addiu(&buf, A1, A1, 2 * off);
496	pg_addiu(&buf, A0, A0, 2 * off);
497	off = -off;
498	do {
499		build_copy_load_pref(&buf, off);
500		build_copy_load(&buf, T0, off);
501		build_copy_load_pref(&buf, off + copy_word_size);
502		build_copy_load(&buf, T1, off + copy_word_size);
503		build_copy_load_pref(&buf, off + 2 * copy_word_size);
504		build_copy_load(&buf, T2, off + 2 * copy_word_size);
505		build_copy_load_pref(&buf, off + 3 * copy_word_size);
506		build_copy_load(&buf, T3, off + 3 * copy_word_size);
507		build_copy_store_pref(&buf, off);
508		build_copy_store(&buf, T0, off);
509		build_copy_store_pref(&buf, off + copy_word_size);
510		build_copy_store(&buf, T1, off + copy_word_size);
511		build_copy_store_pref(&buf, off + 2 * copy_word_size);
512		build_copy_store(&buf, T2, off + 2 * copy_word_size);
513		build_copy_store_pref(&buf, off + 3 * copy_word_size);
514		if (off == -(4 * copy_word_size))
515			uasm_il_bne(&buf, &r, A2, A0, label_copy_pref_both);
516		build_copy_store(&buf, T3, off + 3 * copy_word_size);
517		off += 4 * copy_word_size;
518	} while (off < 0);
519
520	if (pref_bias_copy_load - pref_bias_copy_store) {
521		pg_addiu(&buf, A2, A0,
522			 pref_bias_copy_load - pref_bias_copy_store);
523		uasm_l_copy_pref_store(&l, buf);
524		off = 0;
525		do {
526			build_copy_load(&buf, T0, off);
527			build_copy_load(&buf, T1, off + copy_word_size);
528			build_copy_load(&buf, T2, off + 2 * copy_word_size);
529			build_copy_load(&buf, T3, off + 3 * copy_word_size);
530			build_copy_store_pref(&buf, off);
531			build_copy_store(&buf, T0, off);
532			build_copy_store_pref(&buf, off + copy_word_size);
533			build_copy_store(&buf, T1, off + copy_word_size);
534			build_copy_store_pref(&buf, off + 2 * copy_word_size);
535			build_copy_store(&buf, T2, off + 2 * copy_word_size);
536			build_copy_store_pref(&buf, off + 3 * copy_word_size);
537			build_copy_store(&buf, T3, off + 3 * copy_word_size);
538			off += 4 * copy_word_size;
539		} while (off < half_copy_loop_size);
540		pg_addiu(&buf, A1, A1, 2 * off);
541		pg_addiu(&buf, A0, A0, 2 * off);
542		off = -off;
543		do {
544			build_copy_load(&buf, T0, off);
545			build_copy_load(&buf, T1, off + copy_word_size);
546			build_copy_load(&buf, T2, off + 2 * copy_word_size);
547			build_copy_load(&buf, T3, off + 3 * copy_word_size);
548			build_copy_store_pref(&buf, off);
549			build_copy_store(&buf, T0, off);
550			build_copy_store_pref(&buf, off + copy_word_size);
551			build_copy_store(&buf, T1, off + copy_word_size);
552			build_copy_store_pref(&buf, off + 2 * copy_word_size);
553			build_copy_store(&buf, T2, off + 2 * copy_word_size);
554			build_copy_store_pref(&buf, off + 3 * copy_word_size);
555			if (off == -(4 * copy_word_size))
556				uasm_il_bne(&buf, &r, A2, A0,
557					    label_copy_pref_store);
558			build_copy_store(&buf, T3, off + 3 * copy_word_size);
559			off += 4 * copy_word_size;
560		} while (off < 0);
561	}
562
563	if (pref_bias_copy_store) {
564		pg_addiu(&buf, A2, A0, pref_bias_copy_store);
565		uasm_l_copy_nopref(&l, buf);
566		off = 0;
567		do {
568			build_copy_load(&buf, T0, off);
569			build_copy_load(&buf, T1, off + copy_word_size);
570			build_copy_load(&buf, T2, off + 2 * copy_word_size);
571			build_copy_load(&buf, T3, off + 3 * copy_word_size);
572			build_copy_store(&buf, T0, off);
573			build_copy_store(&buf, T1, off + copy_word_size);
574			build_copy_store(&buf, T2, off + 2 * copy_word_size);
575			build_copy_store(&buf, T3, off + 3 * copy_word_size);
576			off += 4 * copy_word_size;
577		} while (off < half_copy_loop_size);
578		pg_addiu(&buf, A1, A1, 2 * off);
579		pg_addiu(&buf, A0, A0, 2 * off);
580		off = -off;
581		do {
582			build_copy_load(&buf, T0, off);
583			build_copy_load(&buf, T1, off + copy_word_size);
584			build_copy_load(&buf, T2, off + 2 * copy_word_size);
585			build_copy_load(&buf, T3, off + 3 * copy_word_size);
586			build_copy_store(&buf, T0, off);
587			build_copy_store(&buf, T1, off + copy_word_size);
588			build_copy_store(&buf, T2, off + 2 * copy_word_size);
589			if (off == -(4 * copy_word_size))
590				uasm_il_bne(&buf, &r, A2, A0,
591					    label_copy_nopref);
592			build_copy_store(&buf, T3, off + 3 * copy_word_size);
593			off += 4 * copy_word_size;
594		} while (off < 0);
595	}
596
597	uasm_i_jr(&buf, RA);
598	uasm_i_nop(&buf);
599
600	BUG_ON(buf > &__copy_page_end);
601
602	uasm_resolve_relocs(relocs, labels);
603
604	pr_debug("Synthesized copy page handler (%u instructions).\n",
605		 (u32)(buf - &__copy_page_start));
606
607	pr_debug("\t.set push\n");
608	pr_debug("\t.set noreorder\n");
609	for (i = 0; i < (buf - &__copy_page_start); i++)
610		pr_debug("\t.word 0x%08x\n", (&__copy_page_start)[i]);
611	pr_debug("\t.set pop\n");
612}
613
614#ifdef CONFIG_SIBYTE_DMA_PAGEOPS
615extern void clear_page_cpu(void *page);
616extern void copy_page_cpu(void *to, void *from);
617
618/*
619 * Pad descriptors to cacheline, since each is exclusively owned by a
620 * particular CPU.
621 */
622struct dmadscr {
623	u64 dscr_a;
624	u64 dscr_b;
625	u64 pad_a;
626	u64 pad_b;
627} ____cacheline_aligned_in_smp page_descr[DM_NUM_CHANNELS];
628
629void clear_page(void *page)
630{
631	u64 to_phys = CPHYSADDR((unsigned long)page);
632	unsigned int cpu = smp_processor_id();
633
634	/* if the page is not in KSEG0, use old way */
635	if ((long)KSEGX((unsigned long)page) != (long)CKSEG0)
636		return clear_page_cpu(page);
637
638	page_descr[cpu].dscr_a = to_phys | M_DM_DSCRA_ZERO_MEM |
639				 M_DM_DSCRA_L2C_DEST | M_DM_DSCRA_INTERRUPT;
640	page_descr[cpu].dscr_b = V_DM_DSCRB_SRC_LENGTH(PAGE_SIZE);
641	__raw_writeq(1, IOADDR(A_DM_REGISTER(cpu, R_DM_DSCR_COUNT)));
642
643	/*
644	 * Don't really want to do it this way, but there's no
645	 * reliable way to delay completion detection.
646	 */
647	while (!(__raw_readq(IOADDR(A_DM_REGISTER(cpu, R_DM_DSCR_BASE_DEBUG)))
648		 & M_DM_DSCR_BASE_INTERRUPT))
649		;
650	__raw_readq(IOADDR(A_DM_REGISTER(cpu, R_DM_DSCR_BASE)));
651}
652EXPORT_SYMBOL(clear_page);
653
654void copy_page(void *to, void *from)
655{
656	u64 from_phys = CPHYSADDR((unsigned long)from);
657	u64 to_phys = CPHYSADDR((unsigned long)to);
658	unsigned int cpu = smp_processor_id();
659
660	/* if any page is not in KSEG0, use old way */
661	if ((long)KSEGX((unsigned long)to) != (long)CKSEG0
662	    || (long)KSEGX((unsigned long)from) != (long)CKSEG0)
663		return copy_page_cpu(to, from);
664
665	page_descr[cpu].dscr_a = to_phys | M_DM_DSCRA_L2C_DEST |
666				 M_DM_DSCRA_INTERRUPT;
667	page_descr[cpu].dscr_b = from_phys | V_DM_DSCRB_SRC_LENGTH(PAGE_SIZE);
668	__raw_writeq(1, IOADDR(A_DM_REGISTER(cpu, R_DM_DSCR_COUNT)));
669
670	/*
671	 * Don't really want to do it this way, but there's no
672	 * reliable way to delay completion detection.
673	 */
674	while (!(__raw_readq(IOADDR(A_DM_REGISTER(cpu, R_DM_DSCR_BASE_DEBUG)))
675		 & M_DM_DSCR_BASE_INTERRUPT))
676		;
677	__raw_readq(IOADDR(A_DM_REGISTER(cpu, R_DM_DSCR_BASE)));
678}
679EXPORT_SYMBOL(copy_page);
680
681#endif /* CONFIG_SIBYTE_DMA_PAGEOPS */
682