xref: /openbmc/linux/arch/mips/mm/page.c (revision 8e9356c6)
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/module.h>
16 #include <linux/proc_fs.h>
17 
18 #include <asm/bugs.h>
19 #include <asm/cacheops.h>
20 #include <asm/cpu-type.h>
21 #include <asm/inst.h>
22 #include <asm/io.h>
23 #include <asm/page.h>
24 #include <asm/pgtable.h>
25 #include <asm/prefetch.h>
26 #include <asm/bootinfo.h>
27 #include <asm/mipsregs.h>
28 #include <asm/mmu_context.h>
29 #include <asm/cpu.h>
30 #include <asm/war.h>
31 
32 #ifdef CONFIG_SIBYTE_DMA_PAGEOPS
33 #include <asm/sibyte/sb1250.h>
34 #include <asm/sibyte/sb1250_regs.h>
35 #include <asm/sibyte/sb1250_dma.h>
36 #endif
37 
38 #include <asm/uasm.h>
39 
40 /* Registers used in the assembled routines. */
41 #define ZERO 0
42 #define AT 2
43 #define A0 4
44 #define A1 5
45 #define A2 6
46 #define T0 8
47 #define T1 9
48 #define T2 10
49 #define T3 11
50 #define T9 25
51 #define RA 31
52 
53 /* Handle labels (which must be positive integers). */
54 enum label_id {
55 	label_clear_nopref = 1,
56 	label_clear_pref,
57 	label_copy_nopref,
58 	label_copy_pref_both,
59 	label_copy_pref_store,
60 };
61 
62 UASM_L_LA(_clear_nopref)
63 UASM_L_LA(_clear_pref)
64 UASM_L_LA(_copy_nopref)
65 UASM_L_LA(_copy_pref_both)
66 UASM_L_LA(_copy_pref_store)
67 
68 /* We need one branch and therefore one relocation per target label. */
69 static struct uasm_label labels[5];
70 static struct uasm_reloc relocs[5];
71 
72 #define cpu_is_r4600_v1_x()	((read_c0_prid() & 0xfffffff0) == 0x00002010)
73 #define cpu_is_r4600_v2_x()	((read_c0_prid() & 0xfffffff0) == 0x00002020)
74 
75 static int pref_bias_clear_store;
76 static int pref_bias_copy_load;
77 static int pref_bias_copy_store;
78 
79 static u32 pref_src_mode;
80 static u32 pref_dst_mode;
81 
82 static int clear_word_size;
83 static int copy_word_size;
84 
85 static int half_clear_loop_size;
86 static int half_copy_loop_size;
87 
88 static int cache_line_size;
89 #define cache_line_mask() (cache_line_size - 1)
90 
91 static inline void
92 pg_addiu(u32 **buf, unsigned int reg1, unsigned int reg2, unsigned int off)
93 {
94 	if (cpu_has_64bit_gp_regs && DADDI_WAR && r4k_daddiu_bug()) {
95 		if (off > 0x7fff) {
96 			uasm_i_lui(buf, T9, uasm_rel_hi(off));
97 			uasm_i_addiu(buf, T9, T9, uasm_rel_lo(off));
98 		} else
99 			uasm_i_addiu(buf, T9, ZERO, off);
100 		uasm_i_daddu(buf, reg1, reg2, T9);
101 	} else {
102 		if (off > 0x7fff) {
103 			uasm_i_lui(buf, T9, uasm_rel_hi(off));
104 			uasm_i_addiu(buf, T9, T9, uasm_rel_lo(off));
105 			UASM_i_ADDU(buf, reg1, reg2, T9);
106 		} else
107 			UASM_i_ADDIU(buf, reg1, reg2, off);
108 	}
109 }
110 
111 static void set_prefetch_parameters(void)
112 {
113 	if (cpu_has_64bit_gp_regs || cpu_has_64bit_zero_reg)
114 		clear_word_size = 8;
115 	else
116 		clear_word_size = 4;
117 
118 	if (cpu_has_64bit_gp_regs)
119 		copy_word_size = 8;
120 	else
121 		copy_word_size = 4;
122 
123 	/*
124 	 * The pref's used here are using "streaming" hints, which cause the
125 	 * copied data to be kicked out of the cache sooner.  A page copy often
126 	 * ends up copying a lot more data than is commonly used, so this seems
127 	 * to make sense in terms of reducing cache pollution, but I've no real
128 	 * performance data to back this up.
129 	 */
130 	if (cpu_has_prefetch) {
131 		/*
132 		 * XXX: Most prefetch bias values in here are based on
133 		 * guesswork.
134 		 */
135 		cache_line_size = cpu_dcache_line_size();
136 		switch (current_cpu_type()) {
137 		case CPU_R5500:
138 		case CPU_TX49XX:
139 			/* These processors only support the Pref_Load. */
140 			pref_bias_copy_load = 256;
141 			break;
142 
143 		case CPU_R10000:
144 		case CPU_R12000:
145 		case CPU_R14000:
146 			/*
147 			 * Those values have been experimentally tuned for an
148 			 * Origin 200.
149 			 */
150 			pref_bias_clear_store = 512;
151 			pref_bias_copy_load = 256;
152 			pref_bias_copy_store = 256;
153 			pref_src_mode = Pref_LoadStreamed;
154 			pref_dst_mode = Pref_StoreStreamed;
155 			break;
156 
157 		case CPU_SB1:
158 		case CPU_SB1A:
159 			pref_bias_clear_store = 128;
160 			pref_bias_copy_load = 128;
161 			pref_bias_copy_store = 128;
162 			/*
163 			 * SB1 pass1 Pref_LoadStreamed/Pref_StoreStreamed
164 			 * hints are broken.
165 			 */
166 			if (current_cpu_type() == CPU_SB1 &&
167 			    (current_cpu_data.processor_id & 0xff) < 0x02) {
168 				pref_src_mode = Pref_Load;
169 				pref_dst_mode = Pref_Store;
170 			} else {
171 				pref_src_mode = Pref_LoadStreamed;
172 				pref_dst_mode = Pref_StoreStreamed;
173 			}
174 			break;
175 
176 		default:
177 			pref_bias_clear_store = 128;
178 			pref_bias_copy_load = 256;
179 			pref_bias_copy_store = 128;
180 			pref_src_mode = Pref_LoadStreamed;
181 			pref_dst_mode = Pref_PrepareForStore;
182 			break;
183 		}
184 	} else {
185 		if (cpu_has_cache_cdex_s)
186 			cache_line_size = cpu_scache_line_size();
187 		else if (cpu_has_cache_cdex_p)
188 			cache_line_size = cpu_dcache_line_size();
189 	}
190 	/*
191 	 * Too much unrolling will overflow the available space in
192 	 * clear_space_array / copy_page_array.
193 	 */
194 	half_clear_loop_size = min(16 * clear_word_size,
195 				   max(cache_line_size >> 1,
196 				       4 * clear_word_size));
197 	half_copy_loop_size = min(16 * copy_word_size,
198 				  max(cache_line_size >> 1,
199 				      4 * copy_word_size));
200 }
201 
202 static void build_clear_store(u32 **buf, int off)
203 {
204 	if (cpu_has_64bit_gp_regs || cpu_has_64bit_zero_reg) {
205 		uasm_i_sd(buf, ZERO, off, A0);
206 	} else {
207 		uasm_i_sw(buf, ZERO, off, A0);
208 	}
209 }
210 
211 static inline void build_clear_pref(u32 **buf, int off)
212 {
213 	if (off & cache_line_mask())
214 		return;
215 
216 	if (pref_bias_clear_store) {
217 		uasm_i_pref(buf, pref_dst_mode, pref_bias_clear_store + off,
218 			    A0);
219 	} else if (cache_line_size == (half_clear_loop_size << 1)) {
220 		if (cpu_has_cache_cdex_s) {
221 			uasm_i_cache(buf, Create_Dirty_Excl_SD, off, A0);
222 		} else if (cpu_has_cache_cdex_p) {
223 			if (R4600_V1_HIT_CACHEOP_WAR && cpu_is_r4600_v1_x()) {
224 				uasm_i_nop(buf);
225 				uasm_i_nop(buf);
226 				uasm_i_nop(buf);
227 				uasm_i_nop(buf);
228 			}
229 
230 			if (R4600_V2_HIT_CACHEOP_WAR && cpu_is_r4600_v2_x())
231 				uasm_i_lw(buf, ZERO, ZERO, AT);
232 
233 			uasm_i_cache(buf, Create_Dirty_Excl_D, off, A0);
234 		}
235 	}
236 }
237 
238 extern u32 __clear_page_start;
239 extern u32 __clear_page_end;
240 extern u32 __copy_page_start;
241 extern u32 __copy_page_end;
242 
243 void build_clear_page(void)
244 {
245 	int off;
246 	u32 *buf = &__clear_page_start;
247 	struct uasm_label *l = labels;
248 	struct uasm_reloc *r = relocs;
249 	int i;
250 	static atomic_t run_once = ATOMIC_INIT(0);
251 
252 	if (atomic_xchg(&run_once, 1)) {
253 		return;
254 	}
255 
256 	memset(labels, 0, sizeof(labels));
257 	memset(relocs, 0, sizeof(relocs));
258 
259 	set_prefetch_parameters();
260 
261 	/*
262 	 * This algorithm makes the following assumptions:
263 	 *   - The prefetch bias is a multiple of 2 words.
264 	 *   - The prefetch bias is less than one page.
265 	 */
266 	BUG_ON(pref_bias_clear_store % (2 * clear_word_size));
267 	BUG_ON(PAGE_SIZE < pref_bias_clear_store);
268 
269 	off = PAGE_SIZE - pref_bias_clear_store;
270 	if (off > 0xffff || !pref_bias_clear_store)
271 		pg_addiu(&buf, A2, A0, off);
272 	else
273 		uasm_i_ori(&buf, A2, A0, off);
274 
275 	if (R4600_V2_HIT_CACHEOP_WAR && cpu_is_r4600_v2_x())
276 		uasm_i_lui(&buf, AT, 0xa000);
277 
278 	off = cache_line_size ? min(8, pref_bias_clear_store / cache_line_size)
279 				* cache_line_size : 0;
280 	while (off) {
281 		build_clear_pref(&buf, -off);
282 		off -= cache_line_size;
283 	}
284 	uasm_l_clear_pref(&l, buf);
285 	do {
286 		build_clear_pref(&buf, off);
287 		build_clear_store(&buf, off);
288 		off += clear_word_size;
289 	} while (off < half_clear_loop_size);
290 	pg_addiu(&buf, A0, A0, 2 * off);
291 	off = -off;
292 	do {
293 		build_clear_pref(&buf, off);
294 		if (off == -clear_word_size)
295 			uasm_il_bne(&buf, &r, A0, A2, label_clear_pref);
296 		build_clear_store(&buf, off);
297 		off += clear_word_size;
298 	} while (off < 0);
299 
300 	if (pref_bias_clear_store) {
301 		pg_addiu(&buf, A2, A0, pref_bias_clear_store);
302 		uasm_l_clear_nopref(&l, buf);
303 		off = 0;
304 		do {
305 			build_clear_store(&buf, off);
306 			off += clear_word_size;
307 		} while (off < half_clear_loop_size);
308 		pg_addiu(&buf, A0, A0, 2 * off);
309 		off = -off;
310 		do {
311 			if (off == -clear_word_size)
312 				uasm_il_bne(&buf, &r, A0, A2,
313 					    label_clear_nopref);
314 			build_clear_store(&buf, off);
315 			off += clear_word_size;
316 		} while (off < 0);
317 	}
318 
319 	uasm_i_jr(&buf, RA);
320 	uasm_i_nop(&buf);
321 
322 	BUG_ON(buf > &__clear_page_end);
323 
324 	uasm_resolve_relocs(relocs, labels);
325 
326 	pr_debug("Synthesized clear page handler (%u instructions).\n",
327 		 (u32)(buf - &__clear_page_start));
328 
329 	pr_debug("\t.set push\n");
330 	pr_debug("\t.set noreorder\n");
331 	for (i = 0; i < (buf - &__clear_page_start); i++)
332 		pr_debug("\t.word 0x%08x\n", (&__clear_page_start)[i]);
333 	pr_debug("\t.set pop\n");
334 }
335 
336 static void build_copy_load(u32 **buf, int reg, int off)
337 {
338 	if (cpu_has_64bit_gp_regs) {
339 		uasm_i_ld(buf, reg, off, A1);
340 	} else {
341 		uasm_i_lw(buf, reg, off, A1);
342 	}
343 }
344 
345 static void build_copy_store(u32 **buf, int reg, int off)
346 {
347 	if (cpu_has_64bit_gp_regs) {
348 		uasm_i_sd(buf, reg, off, A0);
349 	} else {
350 		uasm_i_sw(buf, reg, off, A0);
351 	}
352 }
353 
354 static inline void build_copy_load_pref(u32 **buf, int off)
355 {
356 	if (off & cache_line_mask())
357 		return;
358 
359 	if (pref_bias_copy_load)
360 		uasm_i_pref(buf, pref_src_mode, pref_bias_copy_load + off, A1);
361 }
362 
363 static inline void build_copy_store_pref(u32 **buf, int off)
364 {
365 	if (off & cache_line_mask())
366 		return;
367 
368 	if (pref_bias_copy_store) {
369 		uasm_i_pref(buf, pref_dst_mode, pref_bias_copy_store + off,
370 			    A0);
371 	} else if (cache_line_size == (half_copy_loop_size << 1)) {
372 		if (cpu_has_cache_cdex_s) {
373 			uasm_i_cache(buf, Create_Dirty_Excl_SD, off, A0);
374 		} else if (cpu_has_cache_cdex_p) {
375 			if (R4600_V1_HIT_CACHEOP_WAR && cpu_is_r4600_v1_x()) {
376 				uasm_i_nop(buf);
377 				uasm_i_nop(buf);
378 				uasm_i_nop(buf);
379 				uasm_i_nop(buf);
380 			}
381 
382 			if (R4600_V2_HIT_CACHEOP_WAR && cpu_is_r4600_v2_x())
383 				uasm_i_lw(buf, ZERO, ZERO, AT);
384 
385 			uasm_i_cache(buf, Create_Dirty_Excl_D, off, A0);
386 		}
387 	}
388 }
389 
390 void build_copy_page(void)
391 {
392 	int off;
393 	u32 *buf = &__copy_page_start;
394 	struct uasm_label *l = labels;
395 	struct uasm_reloc *r = relocs;
396 	int i;
397 	static atomic_t run_once = ATOMIC_INIT(0);
398 
399 	if (atomic_xchg(&run_once, 1)) {
400 		return;
401 	}
402 
403 	memset(labels, 0, sizeof(labels));
404 	memset(relocs, 0, sizeof(relocs));
405 
406 	set_prefetch_parameters();
407 
408 	/*
409 	 * This algorithm makes the following assumptions:
410 	 *   - All prefetch biases are multiples of 8 words.
411 	 *   - The prefetch biases are less than one page.
412 	 *   - The store prefetch bias isn't greater than the load
413 	 *     prefetch bias.
414 	 */
415 	BUG_ON(pref_bias_copy_load % (8 * copy_word_size));
416 	BUG_ON(pref_bias_copy_store % (8 * copy_word_size));
417 	BUG_ON(PAGE_SIZE < pref_bias_copy_load);
418 	BUG_ON(pref_bias_copy_store > pref_bias_copy_load);
419 
420 	off = PAGE_SIZE - pref_bias_copy_load;
421 	if (off > 0xffff || !pref_bias_copy_load)
422 		pg_addiu(&buf, A2, A0, off);
423 	else
424 		uasm_i_ori(&buf, A2, A0, off);
425 
426 	if (R4600_V2_HIT_CACHEOP_WAR && cpu_is_r4600_v2_x())
427 		uasm_i_lui(&buf, AT, 0xa000);
428 
429 	off = cache_line_size ? min(8, pref_bias_copy_load / cache_line_size) *
430 				cache_line_size : 0;
431 	while (off) {
432 		build_copy_load_pref(&buf, -off);
433 		off -= cache_line_size;
434 	}
435 	off = cache_line_size ? min(8, pref_bias_copy_store / cache_line_size) *
436 				cache_line_size : 0;
437 	while (off) {
438 		build_copy_store_pref(&buf, -off);
439 		off -= cache_line_size;
440 	}
441 	uasm_l_copy_pref_both(&l, buf);
442 	do {
443 		build_copy_load_pref(&buf, off);
444 		build_copy_load(&buf, T0, off);
445 		build_copy_load_pref(&buf, off + copy_word_size);
446 		build_copy_load(&buf, T1, off + copy_word_size);
447 		build_copy_load_pref(&buf, off + 2 * copy_word_size);
448 		build_copy_load(&buf, T2, off + 2 * copy_word_size);
449 		build_copy_load_pref(&buf, off + 3 * copy_word_size);
450 		build_copy_load(&buf, T3, off + 3 * copy_word_size);
451 		build_copy_store_pref(&buf, off);
452 		build_copy_store(&buf, T0, off);
453 		build_copy_store_pref(&buf, off + copy_word_size);
454 		build_copy_store(&buf, T1, off + copy_word_size);
455 		build_copy_store_pref(&buf, off + 2 * copy_word_size);
456 		build_copy_store(&buf, T2, off + 2 * copy_word_size);
457 		build_copy_store_pref(&buf, off + 3 * copy_word_size);
458 		build_copy_store(&buf, T3, off + 3 * copy_word_size);
459 		off += 4 * copy_word_size;
460 	} while (off < half_copy_loop_size);
461 	pg_addiu(&buf, A1, A1, 2 * off);
462 	pg_addiu(&buf, A0, A0, 2 * off);
463 	off = -off;
464 	do {
465 		build_copy_load_pref(&buf, off);
466 		build_copy_load(&buf, T0, off);
467 		build_copy_load_pref(&buf, off + copy_word_size);
468 		build_copy_load(&buf, T1, off + copy_word_size);
469 		build_copy_load_pref(&buf, off + 2 * copy_word_size);
470 		build_copy_load(&buf, T2, off + 2 * copy_word_size);
471 		build_copy_load_pref(&buf, off + 3 * copy_word_size);
472 		build_copy_load(&buf, T3, off + 3 * copy_word_size);
473 		build_copy_store_pref(&buf, off);
474 		build_copy_store(&buf, T0, off);
475 		build_copy_store_pref(&buf, off + copy_word_size);
476 		build_copy_store(&buf, T1, off + copy_word_size);
477 		build_copy_store_pref(&buf, off + 2 * copy_word_size);
478 		build_copy_store(&buf, T2, off + 2 * copy_word_size);
479 		build_copy_store_pref(&buf, off + 3 * copy_word_size);
480 		if (off == -(4 * copy_word_size))
481 			uasm_il_bne(&buf, &r, A2, A0, label_copy_pref_both);
482 		build_copy_store(&buf, T3, off + 3 * copy_word_size);
483 		off += 4 * copy_word_size;
484 	} while (off < 0);
485 
486 	if (pref_bias_copy_load - pref_bias_copy_store) {
487 		pg_addiu(&buf, A2, A0,
488 			 pref_bias_copy_load - pref_bias_copy_store);
489 		uasm_l_copy_pref_store(&l, buf);
490 		off = 0;
491 		do {
492 			build_copy_load(&buf, T0, off);
493 			build_copy_load(&buf, T1, off + copy_word_size);
494 			build_copy_load(&buf, T2, off + 2 * copy_word_size);
495 			build_copy_load(&buf, T3, off + 3 * copy_word_size);
496 			build_copy_store_pref(&buf, off);
497 			build_copy_store(&buf, T0, off);
498 			build_copy_store_pref(&buf, off + copy_word_size);
499 			build_copy_store(&buf, T1, off + copy_word_size);
500 			build_copy_store_pref(&buf, off + 2 * copy_word_size);
501 			build_copy_store(&buf, T2, off + 2 * copy_word_size);
502 			build_copy_store_pref(&buf, off + 3 * copy_word_size);
503 			build_copy_store(&buf, T3, off + 3 * copy_word_size);
504 			off += 4 * copy_word_size;
505 		} while (off < half_copy_loop_size);
506 		pg_addiu(&buf, A1, A1, 2 * off);
507 		pg_addiu(&buf, A0, A0, 2 * off);
508 		off = -off;
509 		do {
510 			build_copy_load(&buf, T0, off);
511 			build_copy_load(&buf, T1, off + copy_word_size);
512 			build_copy_load(&buf, T2, off + 2 * copy_word_size);
513 			build_copy_load(&buf, T3, off + 3 * copy_word_size);
514 			build_copy_store_pref(&buf, off);
515 			build_copy_store(&buf, T0, off);
516 			build_copy_store_pref(&buf, off + copy_word_size);
517 			build_copy_store(&buf, T1, off + copy_word_size);
518 			build_copy_store_pref(&buf, off + 2 * copy_word_size);
519 			build_copy_store(&buf, T2, off + 2 * copy_word_size);
520 			build_copy_store_pref(&buf, off + 3 * copy_word_size);
521 			if (off == -(4 * copy_word_size))
522 				uasm_il_bne(&buf, &r, A2, A0,
523 					    label_copy_pref_store);
524 			build_copy_store(&buf, T3, off + 3 * copy_word_size);
525 			off += 4 * copy_word_size;
526 		} while (off < 0);
527 	}
528 
529 	if (pref_bias_copy_store) {
530 		pg_addiu(&buf, A2, A0, pref_bias_copy_store);
531 		uasm_l_copy_nopref(&l, buf);
532 		off = 0;
533 		do {
534 			build_copy_load(&buf, T0, off);
535 			build_copy_load(&buf, T1, off + copy_word_size);
536 			build_copy_load(&buf, T2, off + 2 * copy_word_size);
537 			build_copy_load(&buf, T3, off + 3 * copy_word_size);
538 			build_copy_store(&buf, T0, off);
539 			build_copy_store(&buf, T1, off + copy_word_size);
540 			build_copy_store(&buf, T2, off + 2 * copy_word_size);
541 			build_copy_store(&buf, T3, off + 3 * copy_word_size);
542 			off += 4 * copy_word_size;
543 		} while (off < half_copy_loop_size);
544 		pg_addiu(&buf, A1, A1, 2 * off);
545 		pg_addiu(&buf, A0, A0, 2 * off);
546 		off = -off;
547 		do {
548 			build_copy_load(&buf, T0, off);
549 			build_copy_load(&buf, T1, off + copy_word_size);
550 			build_copy_load(&buf, T2, off + 2 * copy_word_size);
551 			build_copy_load(&buf, T3, off + 3 * copy_word_size);
552 			build_copy_store(&buf, T0, off);
553 			build_copy_store(&buf, T1, off + copy_word_size);
554 			build_copy_store(&buf, T2, off + 2 * copy_word_size);
555 			if (off == -(4 * copy_word_size))
556 				uasm_il_bne(&buf, &r, A2, A0,
557 					    label_copy_nopref);
558 			build_copy_store(&buf, T3, off + 3 * copy_word_size);
559 			off += 4 * copy_word_size;
560 		} while (off < 0);
561 	}
562 
563 	uasm_i_jr(&buf, RA);
564 	uasm_i_nop(&buf);
565 
566 	BUG_ON(buf > &__copy_page_end);
567 
568 	uasm_resolve_relocs(relocs, labels);
569 
570 	pr_debug("Synthesized copy page handler (%u instructions).\n",
571 		 (u32)(buf - &__copy_page_start));
572 
573 	pr_debug("\t.set push\n");
574 	pr_debug("\t.set noreorder\n");
575 	for (i = 0; i < (buf - &__copy_page_start); i++)
576 		pr_debug("\t.word 0x%08x\n", (&__copy_page_start)[i]);
577 	pr_debug("\t.set pop\n");
578 }
579 
580 #ifdef CONFIG_SIBYTE_DMA_PAGEOPS
581 extern void clear_page_cpu(void *page);
582 extern void copy_page_cpu(void *to, void *from);
583 
584 /*
585  * Pad descriptors to cacheline, since each is exclusively owned by a
586  * particular CPU.
587  */
588 struct dmadscr {
589 	u64 dscr_a;
590 	u64 dscr_b;
591 	u64 pad_a;
592 	u64 pad_b;
593 } ____cacheline_aligned_in_smp page_descr[DM_NUM_CHANNELS];
594 
595 void sb1_dma_init(void)
596 {
597 	int i;
598 
599 	for (i = 0; i < DM_NUM_CHANNELS; i++) {
600 		const u64 base_val = CPHYSADDR((unsigned long)&page_descr[i]) |
601 				     V_DM_DSCR_BASE_RINGSZ(1);
602 		void *base_reg = IOADDR(A_DM_REGISTER(i, R_DM_DSCR_BASE));
603 
604 		__raw_writeq(base_val, base_reg);
605 		__raw_writeq(base_val | M_DM_DSCR_BASE_RESET, base_reg);
606 		__raw_writeq(base_val | M_DM_DSCR_BASE_ENABL, base_reg);
607 	}
608 }
609 
610 void clear_page(void *page)
611 {
612 	u64 to_phys = CPHYSADDR((unsigned long)page);
613 	unsigned int cpu = smp_processor_id();
614 
615 	/* if the page is not in KSEG0, use old way */
616 	if ((long)KSEGX((unsigned long)page) != (long)CKSEG0)
617 		return clear_page_cpu(page);
618 
619 	page_descr[cpu].dscr_a = to_phys | M_DM_DSCRA_ZERO_MEM |
620 				 M_DM_DSCRA_L2C_DEST | M_DM_DSCRA_INTERRUPT;
621 	page_descr[cpu].dscr_b = V_DM_DSCRB_SRC_LENGTH(PAGE_SIZE);
622 	__raw_writeq(1, IOADDR(A_DM_REGISTER(cpu, R_DM_DSCR_COUNT)));
623 
624 	/*
625 	 * Don't really want to do it this way, but there's no
626 	 * reliable way to delay completion detection.
627 	 */
628 	while (!(__raw_readq(IOADDR(A_DM_REGISTER(cpu, R_DM_DSCR_BASE_DEBUG)))
629 		 & M_DM_DSCR_BASE_INTERRUPT))
630 		;
631 	__raw_readq(IOADDR(A_DM_REGISTER(cpu, R_DM_DSCR_BASE)));
632 }
633 
634 void copy_page(void *to, void *from)
635 {
636 	u64 from_phys = CPHYSADDR((unsigned long)from);
637 	u64 to_phys = CPHYSADDR((unsigned long)to);
638 	unsigned int cpu = smp_processor_id();
639 
640 	/* if any page is not in KSEG0, use old way */
641 	if ((long)KSEGX((unsigned long)to) != (long)CKSEG0
642 	    || (long)KSEGX((unsigned long)from) != (long)CKSEG0)
643 		return copy_page_cpu(to, from);
644 
645 	page_descr[cpu].dscr_a = to_phys | M_DM_DSCRA_L2C_DEST |
646 				 M_DM_DSCRA_INTERRUPT;
647 	page_descr[cpu].dscr_b = from_phys | V_DM_DSCRB_SRC_LENGTH(PAGE_SIZE);
648 	__raw_writeq(1, IOADDR(A_DM_REGISTER(cpu, R_DM_DSCR_COUNT)));
649 
650 	/*
651 	 * Don't really want to do it this way, but there's no
652 	 * reliable way to delay completion detection.
653 	 */
654 	while (!(__raw_readq(IOADDR(A_DM_REGISTER(cpu, R_DM_DSCR_BASE_DEBUG)))
655 		 & M_DM_DSCR_BASE_INTERRUPT))
656 		;
657 	__raw_readq(IOADDR(A_DM_REGISTER(cpu, R_DM_DSCR_BASE)));
658 }
659 
660 #endif /* CONFIG_SIBYTE_DMA_PAGEOPS */
661