xref: /openbmc/u-boot/arch/mips/lib/cache_init.S (revision ae485b54) 
1/* SPDX-License-Identifier: GPL-2.0+ */
2/*
3 *  Cache-handling routined for MIPS CPUs
4 *
5 *  Copyright (c) 2003	Wolfgang Denk <wd@denx.de>
6 */
7
8#include <asm-offsets.h>
9#include <config.h>
10#include <asm/asm.h>
11#include <asm/regdef.h>
12#include <asm/mipsregs.h>
13#include <asm/addrspace.h>
14#include <asm/cacheops.h>
15#include <asm/cm.h>
16
17#ifndef CONFIG_SYS_MIPS_CACHE_MODE
18#define CONFIG_SYS_MIPS_CACHE_MODE CONF_CM_CACHABLE_NONCOHERENT
19#endif
20
21#define INDEX_BASE	CKSEG0
22
23	.macro	f_fill64 dst, offset, val
24	LONG_S	\val, (\offset +  0 * LONGSIZE)(\dst)
25	LONG_S	\val, (\offset +  1 * LONGSIZE)(\dst)
26	LONG_S	\val, (\offset +  2 * LONGSIZE)(\dst)
27	LONG_S	\val, (\offset +  3 * LONGSIZE)(\dst)
28	LONG_S	\val, (\offset +  4 * LONGSIZE)(\dst)
29	LONG_S	\val, (\offset +  5 * LONGSIZE)(\dst)
30	LONG_S	\val, (\offset +  6 * LONGSIZE)(\dst)
31	LONG_S	\val, (\offset +  7 * LONGSIZE)(\dst)
32#if LONGSIZE == 4
33	LONG_S	\val, (\offset +  8 * LONGSIZE)(\dst)
34	LONG_S	\val, (\offset +  9 * LONGSIZE)(\dst)
35	LONG_S	\val, (\offset + 10 * LONGSIZE)(\dst)
36	LONG_S	\val, (\offset + 11 * LONGSIZE)(\dst)
37	LONG_S	\val, (\offset + 12 * LONGSIZE)(\dst)
38	LONG_S	\val, (\offset + 13 * LONGSIZE)(\dst)
39	LONG_S	\val, (\offset + 14 * LONGSIZE)(\dst)
40	LONG_S	\val, (\offset + 15 * LONGSIZE)(\dst)
41#endif
42	.endm
43
44	.macro cache_loop	curr, end, line_sz, op
4510:	cache		\op, 0(\curr)
46	PTR_ADDU	\curr, \curr, \line_sz
47	bne		\curr, \end, 10b
48	.endm
49
50	.macro	l1_info		sz, line_sz, off
51	.set	push
52	.set	noat
53
54	mfc0	$1, CP0_CONFIG, 1
55
56	/* detect line size */
57	srl	\line_sz, $1, \off + MIPS_CONF1_DL_SHF - MIPS_CONF1_DA_SHF
58	andi	\line_sz, \line_sz, (MIPS_CONF1_DL >> MIPS_CONF1_DL_SHF)
59	move	\sz, zero
60	beqz	\line_sz, 10f
61	li	\sz, 2
62	sllv	\line_sz, \sz, \line_sz
63
64	/* detect associativity */
65	srl	\sz, $1, \off + MIPS_CONF1_DA_SHF - MIPS_CONF1_DA_SHF
66	andi	\sz, \sz, (MIPS_CONF1_DA >> MIPS_CONF1_DA_SHF)
67	addiu	\sz, \sz, 1
68
69	/* sz *= line_sz */
70	mul	\sz, \sz, \line_sz
71
72	/* detect log32(sets) */
73	srl	$1, $1, \off + MIPS_CONF1_DS_SHF - MIPS_CONF1_DA_SHF
74	andi	$1, $1, (MIPS_CONF1_DS >> MIPS_CONF1_DS_SHF)
75	addiu	$1, $1, 1
76	andi	$1, $1, 0x7
77
78	/* sz <<= log32(sets) */
79	sllv	\sz, \sz, $1
80
81	/* sz *= 32 */
82	li	$1, 32
83	mul	\sz, \sz, $1
8410:
85	.set	pop
86	.endm
87/*
88 * mips_cache_reset - low level initialisation of the primary caches
89 *
90 * This routine initialises the primary caches to ensure that they have good
91 * parity.  It must be called by the ROM before any cached locations are used
92 * to prevent the possibility of data with bad parity being written to memory.
93 *
94 * To initialise the instruction cache it is essential that a source of data
95 * with good parity is available. This routine will initialise an area of
96 * memory starting at location zero to be used as a source of parity.
97 *
98 * Note that this function does not follow the standard calling convention &
99 * may clobber typically callee-saved registers.
100 *
101 * RETURNS: N/A
102 *
103 */
104#define R_RETURN	s0
105#define R_IC_SIZE	s1
106#define R_IC_LINE	s2
107#define R_DC_SIZE	s3
108#define R_DC_LINE	s4
109#define R_L2_SIZE	s5
110#define R_L2_LINE	s6
111#define R_L2_BYPASSED	s7
112#define R_L2_L2C	t8
113LEAF(mips_cache_reset)
114	move	R_RETURN, ra
115
116#ifdef CONFIG_MIPS_L2_CACHE
117	/*
118	 * For there to be an L2 present, Config2 must be present. If it isn't
119	 * then we proceed knowing there's no L2 cache.
120	 */
121	move	R_L2_SIZE, zero
122	move	R_L2_LINE, zero
123	move	R_L2_BYPASSED, zero
124	move	R_L2_L2C, zero
125	mfc0	t0, CP0_CONFIG, 1
126	bgez	t0, l2_probe_done
127
128	/*
129	 * From MIPSr6 onwards the L2 cache configuration might not be reported
130	 * by Config2. The Config5.L2C bit indicates whether this is the case,
131	 * and if it is then we need knowledge of where else to look. For cores
132	 * from Imagination Technologies this is a CM GCR.
133	 */
134# if __mips_isa_rev >= 6
135	/* Check that Config5 exists */
136	mfc0	t0, CP0_CONFIG, 2
137	bgez	t0, l2_probe_cop0
138	mfc0	t0, CP0_CONFIG, 3
139	bgez	t0, l2_probe_cop0
140	mfc0	t0, CP0_CONFIG, 4
141	bgez	t0, l2_probe_cop0
142
143	/* Check Config5.L2C is set */
144	mfc0	t0, CP0_CONFIG, 5
145	and	R_L2_L2C, t0, MIPS_CONF5_L2C
146	beqz	R_L2_L2C, l2_probe_cop0
147
148	/* Config5.L2C is set */
149#  ifdef CONFIG_MIPS_CM
150	/* The CM will provide L2 configuration */
151	PTR_LI	t0, CKSEG1ADDR(CONFIG_MIPS_CM_BASE)
152	lw	t1, GCR_L2_CONFIG(t0)
153	bgez	t1, l2_probe_done
154
155	ext	R_L2_LINE, t1, \
156		GCR_L2_CONFIG_LINESZ_SHIFT, GCR_L2_CONFIG_LINESZ_BITS
157	beqz	R_L2_LINE, l2_probe_done
158	li	t2, 2
159	sllv	R_L2_LINE, t2, R_L2_LINE
160
161	ext	t2, t1, GCR_L2_CONFIG_ASSOC_SHIFT, GCR_L2_CONFIG_ASSOC_BITS
162	addiu	t2, t2, 1
163	mul	R_L2_SIZE, R_L2_LINE, t2
164
165	ext	t2, t1, GCR_L2_CONFIG_SETSZ_SHIFT, GCR_L2_CONFIG_SETSZ_BITS
166	sllv	R_L2_SIZE, R_L2_SIZE, t2
167	li	t2, 64
168	mul	R_L2_SIZE, R_L2_SIZE, t2
169
170	/* Bypass the L2 cache so that we can init the L1s early */
171	or	t1, t1, GCR_L2_CONFIG_BYPASS
172	sw	t1, GCR_L2_CONFIG(t0)
173	sync
174	li	R_L2_BYPASSED, 1
175
176	/* Zero the L2 tag registers */
177	sw	zero, GCR_L2_TAG_ADDR(t0)
178	sw	zero, GCR_L2_TAG_ADDR_UPPER(t0)
179	sw	zero, GCR_L2_TAG_STATE(t0)
180	sw	zero, GCR_L2_TAG_STATE_UPPER(t0)
181	sw	zero, GCR_L2_DATA(t0)
182	sw	zero, GCR_L2_DATA_UPPER(t0)
183	sync
184#  else
185	/* We don't know how to retrieve L2 configuration on this system */
186#  endif
187	b	l2_probe_done
188# endif
189
190	/*
191	 * For pre-r6 systems, or r6 systems with Config5.L2C==0, probe the L2
192	 * cache configuration from the cop0 Config2 register.
193	 */
194l2_probe_cop0:
195	mfc0	t0, CP0_CONFIG, 2
196
197	srl	R_L2_LINE, t0, MIPS_CONF2_SL_SHF
198	andi	R_L2_LINE, R_L2_LINE, MIPS_CONF2_SL >> MIPS_CONF2_SL_SHF
199	beqz	R_L2_LINE, l2_probe_done
200	li	t1, 2
201	sllv	R_L2_LINE, t1, R_L2_LINE
202
203	srl	t1, t0, MIPS_CONF2_SA_SHF
204	andi	t1, t1, MIPS_CONF2_SA >> MIPS_CONF2_SA_SHF
205	addiu	t1, t1, 1
206	mul	R_L2_SIZE, R_L2_LINE, t1
207
208	srl	t1, t0, MIPS_CONF2_SS_SHF
209	andi	t1, t1, MIPS_CONF2_SS >> MIPS_CONF2_SS_SHF
210	sllv	R_L2_SIZE, R_L2_SIZE, t1
211	li	t1, 64
212	mul	R_L2_SIZE, R_L2_SIZE, t1
213
214	/* Attempt to bypass the L2 so that we can init the L1s early */
215	or	t0, t0, MIPS_CONF2_L2B
216	mtc0	t0, CP0_CONFIG, 2
217	ehb
218	mfc0	t0, CP0_CONFIG, 2
219	and	R_L2_BYPASSED, t0, MIPS_CONF2_L2B
220
221	/* Zero the L2 tag registers */
222	mtc0	zero, CP0_TAGLO, 4
223	ehb
224l2_probe_done:
225#endif
226
227#ifndef CONFIG_SYS_CACHE_SIZE_AUTO
228	li	R_IC_SIZE, CONFIG_SYS_ICACHE_SIZE
229	li	R_IC_LINE, CONFIG_SYS_ICACHE_LINE_SIZE
230#else
231	l1_info	R_IC_SIZE, R_IC_LINE, MIPS_CONF1_IA_SHF
232#endif
233
234#ifndef CONFIG_SYS_CACHE_SIZE_AUTO
235	li	R_DC_SIZE, CONFIG_SYS_DCACHE_SIZE
236	li	R_DC_LINE, CONFIG_SYS_DCACHE_LINE_SIZE
237#else
238	l1_info	R_DC_SIZE, R_DC_LINE, MIPS_CONF1_DA_SHF
239#endif
240
241#ifdef CONFIG_SYS_MIPS_CACHE_INIT_RAM_LOAD
242
243	/* Determine the largest L1 cache size */
244#ifndef CONFIG_SYS_CACHE_SIZE_AUTO
245#if CONFIG_SYS_ICACHE_SIZE > CONFIG_SYS_DCACHE_SIZE
246	li	v0, CONFIG_SYS_ICACHE_SIZE
247#else
248	li	v0, CONFIG_SYS_DCACHE_SIZE
249#endif
250#else
251	move	v0, R_IC_SIZE
252	sltu	t1, R_IC_SIZE, R_DC_SIZE
253	movn	v0, R_DC_SIZE, t1
254#endif
255	/*
256	 * Now clear that much memory starting from zero.
257	 */
258	PTR_LI		a0, CKSEG1
259	PTR_ADDU	a1, a0, v0
2602:	PTR_ADDIU	a0, 64
261	f_fill64	a0, -64, zero
262	bne		a0, a1, 2b
263
264#endif /* CONFIG_SYS_MIPS_CACHE_INIT_RAM_LOAD */
265
266#ifdef CONFIG_MIPS_L2_CACHE
267	/*
268	 * If the L2 is bypassed, init the L1 first so that we can execute the
269	 * rest of the cache initialisation using the L1 instruction cache.
270	 */
271	bnez		R_L2_BYPASSED, l1_init
272
273l2_init:
274	PTR_LI		t0, INDEX_BASE
275	PTR_ADDU	t1, t0, R_L2_SIZE
2761:	cache		INDEX_STORE_TAG_SD, 0(t0)
277	PTR_ADDU	t0, t0, R_L2_LINE
278	bne		t0, t1, 1b
279
280	/*
281	 * If the L2 was bypassed then we already initialised the L1s before
282	 * the L2, so we are now done.
283	 */
284	bnez		R_L2_BYPASSED, l2_unbypass
285#endif
286
287	/*
288	 * The TagLo registers used depend upon the CPU implementation, but the
289	 * architecture requires that it is safe for software to write to both
290	 * TagLo selects 0 & 2 covering supported cases.
291	 */
292l1_init:
293	mtc0		zero, CP0_TAGLO
294	mtc0		zero, CP0_TAGLO, 2
295	ehb
296
297	/*
298	 * The caches are probably in an indeterminate state, so we force good
299	 * parity into them by doing an invalidate for each line. If
300	 * CONFIG_SYS_MIPS_CACHE_INIT_RAM_LOAD is set then we'll proceed to
301	 * perform a load/fill & a further invalidate for each line, assuming
302	 * that the bottom of RAM (having just been cleared) will generate good
303	 * parity for the cache.
304	 */
305
306	/*
307	 * Initialize the I-cache first,
308	 */
309	blez		R_IC_SIZE, 1f
310	PTR_LI		t0, INDEX_BASE
311	PTR_ADDU	t1, t0, R_IC_SIZE
312	/* clear tag to invalidate */
313	cache_loop	t0, t1, R_IC_LINE, INDEX_STORE_TAG_I
314#ifdef CONFIG_SYS_MIPS_CACHE_INIT_RAM_LOAD
315	/* fill once, so data field parity is correct */
316	PTR_LI		t0, INDEX_BASE
317	cache_loop	t0, t1, R_IC_LINE, FILL
318	/* invalidate again - prudent but not strictly neccessary */
319	PTR_LI		t0, INDEX_BASE
320	cache_loop	t0, t1, R_IC_LINE, INDEX_STORE_TAG_I
321#endif
322
323	/* Enable use of the I-cache by setting Config.K0 */
324	sync
325	mfc0		t0, CP0_CONFIG
326	li		t1, CONFIG_SYS_MIPS_CACHE_MODE
327#if __mips_isa_rev >= 2
328	ins		t0, t1, 0, 3
329#else
330	ori		t0, t0, CONF_CM_CMASK
331	xori		t0, t0, CONF_CM_CMASK
332	or		t0, t0, t1
333#endif
334	mtc0		t0, CP0_CONFIG
335
336	/*
337	 * then initialize D-cache.
338	 */
3391:	blez		R_DC_SIZE, 3f
340	PTR_LI		t0, INDEX_BASE
341	PTR_ADDU	t1, t0, R_DC_SIZE
342	/* clear all tags */
343	cache_loop	t0, t1, R_DC_LINE, INDEX_STORE_TAG_D
344#ifdef CONFIG_SYS_MIPS_CACHE_INIT_RAM_LOAD
345	/* load from each line (in cached space) */
346	PTR_LI		t0, INDEX_BASE
3472:	LONG_L		zero, 0(t0)
348	PTR_ADDU	t0, R_DC_LINE
349	bne		t0, t1, 2b
350	/* clear all tags */
351	PTR_LI		t0, INDEX_BASE
352	cache_loop	t0, t1, R_DC_LINE, INDEX_STORE_TAG_D
353#endif
3543:
355
356#ifdef CONFIG_MIPS_L2_CACHE
357	/* If the L2 isn't bypassed then we're done */
358	beqz		R_L2_BYPASSED, return
359
360	/* The L2 is bypassed - go initialise it */
361	b		l2_init
362
363l2_unbypass:
364# if __mips_isa_rev >= 6
365	beqz		R_L2_L2C, 1f
366
367	li		t0, CKSEG1ADDR(CONFIG_MIPS_CM_BASE)
368	lw		t1, GCR_L2_CONFIG(t0)
369	xor		t1, t1, GCR_L2_CONFIG_BYPASS
370	sw		t1, GCR_L2_CONFIG(t0)
371	sync
372	ehb
373	b		2f
374# endif
3751:	mfc0		t0, CP0_CONFIG, 2
376	xor		t0, t0, MIPS_CONF2_L2B
377	mtc0		t0, CP0_CONFIG, 2
378	ehb
379
3802:
381# ifdef CONFIG_MIPS_CM
382	/* Config3 must exist for a CM to be present */
383	mfc0		t0, CP0_CONFIG, 1
384	bgez		t0, 2f
385	mfc0		t0, CP0_CONFIG, 2
386	bgez		t0, 2f
387
388	/* Check Config3.CMGCR to determine CM presence */
389	mfc0		t0, CP0_CONFIG, 3
390	and		t0, t0, MIPS_CONF3_CMGCR
391	beqz		t0, 2f
392
393	/* Change Config.K0 to a coherent CCA */
394	mfc0		t0, CP0_CONFIG
395	li		t1, CONF_CM_CACHABLE_COW
396#if __mips_isa_rev >= 2
397	ins		t0, t1, 0, 3
398#else
399	ori		t0, t0, CONF_CM_CMASK
400	xori		t0, t0, CONF_CM_CMASK
401	or		t0, t0, t1
402#endif
403	mtc0		t0, CP0_CONFIG
404
405	/*
406	 * Join the coherent domain such that the caches of this core are kept
407	 * coherent with those of other cores.
408	 */
409	PTR_LI		t0, CKSEG1ADDR(CONFIG_MIPS_CM_BASE)
410	lw		t1, GCR_REV(t0)
411	li		t2, GCR_REV_CM3
412	li		t3, GCR_Cx_COHERENCE_EN
413	bge		t1, t2, 1f
414	li		t3, GCR_Cx_COHERENCE_DOM_EN
4151:	sw		t3, GCR_Cx_COHERENCE(t0)
416	ehb
4172:
418# endif
419#endif
420
421return:
422	/* Ensure all cache operations complete before returning */
423	sync
424	jr	ra
425	END(mips_cache_reset)
426
427/*
428 * dcache_status - get cache status
429 *
430 * RETURNS: 0 - cache disabled; 1 - cache enabled
431 *
432 */
433LEAF(dcache_status)
434	mfc0	t0, CP0_CONFIG
435	li	t1, CONF_CM_UNCACHED
436	andi	t0, t0, CONF_CM_CMASK
437	move	v0, zero
438	beq	t0, t1, 2f
439	li	v0, 1
4402:	jr	ra
441	END(dcache_status)
442
443/*
444 * dcache_disable - disable cache
445 *
446 * RETURNS: N/A
447 *
448 */
449LEAF(dcache_disable)
450	mfc0	t0, CP0_CONFIG
451	li	t1, -8
452	and	t0, t0, t1
453	ori	t0, t0, CONF_CM_UNCACHED
454	mtc0	t0, CP0_CONFIG
455	jr	ra
456	END(dcache_disable)
457
458/*
459 * dcache_enable - enable cache
460 *
461 * RETURNS: N/A
462 *
463 */
464LEAF(dcache_enable)
465	mfc0	t0, CP0_CONFIG
466	ori	t0, CONF_CM_CMASK
467	xori	t0, CONF_CM_CMASK
468	ori	t0, CONFIG_SYS_MIPS_CACHE_MODE
469	mtc0	t0, CP0_CONFIG
470	jr	ra
471	END(dcache_enable)
472