1/* SPDX-License-Identifier: GPL-2.0-or-later */
2/*
3 * linux/arch/arm/mm/arm925.S: MMU functions for ARM925
4 *
5 * Copyright (C) 1999,2000 ARM Limited
6 * Copyright (C) 2000 Deep Blue Solutions Ltd.
7 * Copyright (C) 2002 RidgeRun, Inc.
8 * Copyright (C) 2002-2003 MontaVista Software, Inc.
9 *
10 * Update for Linux-2.6 and cache flush improvements
11 * Copyright (C) 2004 Nokia Corporation by Tony Lindgren <tony@atomide.com>
12 *
13 * hacked for non-paged-MM by Hyok S. Choi, 2004.
14 *
15 * These are the low level assembler for performing cache and TLB
16 * functions on the arm925.
17 *
18 * CONFIG_CPU_ARM925_CPU_IDLE -> nohlt
19 *
20 * Some additional notes based on deciphering the TI TRM on OMAP-5910:
21 *
22 * NOTE1: The TI925T Configuration Register bit "D-cache clean and flush
23 * entry mode" must be 0 to flush the entries in both segments
24 * at once. This is the default value. See TRM 2-20 and 2-24 for
25 * more information.
26 *
27 * NOTE2: Default is the "D-cache clean and flush entry mode". It looks
28 * like the "Transparent mode" must be on for partial cache flushes
29 * to work in this mode. This mode only works with 16-bit external
30 * memory. See TRM 2-24 for more information.
31 *
32 * NOTE3: Write-back cache flushing seems to be flakey with devices using
33 * direct memory access, such as USB OHCI. The workaround is to use
34 * write-through cache with CONFIG_CPU_DCACHE_WRITETHROUGH (this is
35 * the default for OMAP-1510).
36 */
37
38#include <linux/linkage.h>
39#include <linux/init.h>
40#include <linux/pgtable.h>
41#include <asm/assembler.h>
42#include <asm/hwcap.h>
43#include <asm/pgtable-hwdef.h>
44#include <asm/page.h>
45#include <asm/ptrace.h>
46#include "proc-macros.S"
47
48/*
49 * The size of one data cache line.
50 */
51#define CACHE_DLINESIZE 16
52
53/*
54 * The number of data cache segments.
55 */
56#define CACHE_DSEGMENTS 2
57
58/*
59 * The number of lines in a cache segment.
60 */
61#define CACHE_DENTRIES 256
62
63/*
64 * This is the size at which it becomes more efficient to
65 * clean the whole cache, rather than using the individual
66 * cache line maintenance instructions.
67 */
68#define CACHE_DLIMIT 8192
69
70 .text
71/*
72 * cpu_arm925_proc_init()
73 */
74ENTRY(cpu_arm925_proc_init)
75 ret lr
76
77/*
78 * cpu_arm925_proc_fin()
79 */
80ENTRY(cpu_arm925_proc_fin)
81 mrc p15, 0, r0, c1, c0, 0 @ ctrl register
82 bic r0, r0, #0x1000 @ ...i............
83 bic r0, r0, #0x000e @ ............wca.
84 mcr p15, 0, r0, c1, c0, 0 @ disable caches
85 ret lr
86
87/*
88 * cpu_arm925_reset(loc)
89 *
90 * Perform a soft reset of the system. Put the CPU into the
91 * same state as it would be if it had been reset, and branch
92 * to what would be the reset vector.
93 *
94 * loc: location to jump to for soft reset
95 */
96 .align 5
97 .pushsection .idmap.text, "ax"
98ENTRY(cpu_arm925_reset)
99 /* Send software reset to MPU and DSP */
100 mov ip, #0xff000000
101 orr ip, ip, #0x00fe0000
102 orr ip, ip, #0x0000ce00
103 mov r4, #1
104 strh r4, [ip, #0x10]
105ENDPROC(cpu_arm925_reset)
106 .popsection
107
108 mov ip, #0
109 mcr p15, 0, ip, c7, c7, 0 @ invalidate I,D caches
110 mcr p15, 0, ip, c7, c10, 4 @ drain WB
111#ifdef CONFIG_MMU
112 mcr p15, 0, ip, c8, c7, 0 @ invalidate I & D TLBs
113#endif
114 mrc p15, 0, ip, c1, c0, 0 @ ctrl register
115 bic ip, ip, #0x000f @ ............wcam
116 bic ip, ip, #0x1100 @ ...i...s........
117 mcr p15, 0, ip, c1, c0, 0 @ ctrl register
118 ret r0
119
120/*
121 * cpu_arm925_do_idle()
122 *
123 * Called with IRQs disabled
124 */
125 .align 10
126ENTRY(cpu_arm925_do_idle)
127 mov r0, #0
128 mrc p15, 0, r1, c1, c0, 0 @ Read control register
129 mcr p15, 0, r0, c7, c10, 4 @ Drain write buffer
130 bic r2, r1, #1 << 12
131 mcr p15, 0, r2, c1, c0, 0 @ Disable I cache
132 mcr p15, 0, r0, c7, c0, 4 @ Wait for interrupt
133 mcr p15, 0, r1, c1, c0, 0 @ Restore ICache enable
134 ret lr
135
136/*
137 * flush_icache_all()
138 *
139 * Unconditionally clean and invalidate the entire icache.
140 */
141ENTRY(arm925_flush_icache_all)
142 mov r0, #0
143 mcr p15, 0, r0, c7, c5, 0 @ invalidate I cache
144 ret lr
145ENDPROC(arm925_flush_icache_all)
146
147/*
148 * flush_user_cache_all()
149 *
150 * Clean and invalidate all cache entries in a particular
151 * address space.
152 */
153ENTRY(arm925_flush_user_cache_all)
154 /* FALLTHROUGH */
155
156/*
157 * flush_kern_cache_all()
158 *
159 * Clean and invalidate the entire cache.
160 */
161ENTRY(arm925_flush_kern_cache_all)
162 mov r2, #VM_EXEC
163 mov ip, #0
164__flush_whole_cache:
165#ifdef CONFIG_CPU_DCACHE_WRITETHROUGH
166 mcr p15, 0, ip, c7, c6, 0 @ invalidate D cache
167#else
168 /* Flush entries in both segments at once, see NOTE1 above */
169 mov r3, #(CACHE_DENTRIES - 1) << 4 @ 256 entries in segment
1702: mcr p15, 0, r3, c7, c14, 2 @ clean+invalidate D index
171 subs r3, r3, #1 << 4
172 bcs 2b @ entries 255 to 0
173#endif
174 tst r2, #VM_EXEC
175 mcrne p15, 0, ip, c7, c5, 0 @ invalidate I cache
176 mcrne p15, 0, ip, c7, c10, 4 @ drain WB
177 ret lr
178
179/*
180 * flush_user_cache_range(start, end, flags)
181 *
182 * Clean and invalidate a range of cache entries in the
183 * specified address range.
184 *
185 * - start - start address (inclusive)
186 * - end - end address (exclusive)
187 * - flags - vm_flags describing address space
188 */
189ENTRY(arm925_flush_user_cache_range)
190 mov ip, #0
191 sub r3, r1, r0 @ calculate total size
192 cmp r3, #CACHE_DLIMIT
193 bgt __flush_whole_cache
1941: tst r2, #VM_EXEC
195#ifdef CONFIG_CPU_DCACHE_WRITETHROUGH
196 mcr p15, 0, r0, c7, c6, 1 @ invalidate D entry
197 mcrne p15, 0, r0, c7, c5, 1 @ invalidate I entry
198 add r0, r0, #CACHE_DLINESIZE
199 mcr p15, 0, r0, c7, c6, 1 @ invalidate D entry
200 mcrne p15, 0, r0, c7, c5, 1 @ invalidate I entry
201 add r0, r0, #CACHE_DLINESIZE
202#else
203 mcr p15, 0, r0, c7, c14, 1 @ clean and invalidate D entry
204 mcrne p15, 0, r0, c7, c5, 1 @ invalidate I entry
205 add r0, r0, #CACHE_DLINESIZE
206 mcr p15, 0, r0, c7, c14, 1 @ clean and invalidate D entry
207 mcrne p15, 0, r0, c7, c5, 1 @ invalidate I entry
208 add r0, r0, #CACHE_DLINESIZE
209#endif
210 cmp r0, r1
211 blo 1b
212 tst r2, #VM_EXEC
213 mcrne p15, 0, ip, c7, c10, 4 @ drain WB
214 ret lr
215
216/*
217 * coherent_kern_range(start, end)
218 *
219 * Ensure coherency between the Icache and the Dcache in the
220 * region described by start, end. If you have non-snooping
221 * Harvard caches, you need to implement this function.
222 *
223 * - start - virtual start address
224 * - end - virtual end address
225 */
226ENTRY(arm925_coherent_kern_range)
227 /* FALLTHROUGH */
228
229/*
230 * coherent_user_range(start, end)
231 *
232 * Ensure coherency between the Icache and the Dcache in the
233 * region described by start, end. If you have non-snooping
234 * Harvard caches, you need to implement this function.
235 *
236 * - start - virtual start address
237 * - end - virtual end address
238 */
239ENTRY(arm925_coherent_user_range)
240 bic r0, r0, #CACHE_DLINESIZE - 1
2411: mcr p15, 0, r0, c7, c10, 1 @ clean D entry
242 mcr p15, 0, r0, c7, c5, 1 @ invalidate I entry
243 add r0, r0, #CACHE_DLINESIZE
244 cmp r0, r1
245 blo 1b
246 mcr p15, 0, r0, c7, c10, 4 @ drain WB
247 mov r0, #0
248 ret lr
249
250/*
251 * flush_kern_dcache_area(void *addr, size_t size)
252 *
253 * Ensure no D cache aliasing occurs, either with itself or
254 * the I cache
255 *
256 * - addr - kernel address
257 * - size - region size
258 */
259ENTRY(arm925_flush_kern_dcache_area)
260 add r1, r0, r1
2611: mcr p15, 0, r0, c7, c14, 1 @ clean+invalidate D entry
262 add r0, r0, #CACHE_DLINESIZE
263 cmp r0, r1
264 blo 1b
265 mov r0, #0
266 mcr p15, 0, r0, c7, c5, 0 @ invalidate I cache
267 mcr p15, 0, r0, c7, c10, 4 @ drain WB
268 ret lr
269
270/*
271 * dma_inv_range(start, end)
272 *
273 * Invalidate (discard) the specified virtual address range.
274 * May not write back any entries. If 'start' or 'end'
275 * are not cache line aligned, those lines must be written
276 * back.
277 *
278 * - start - virtual start address
279 * - end - virtual end address
280 *
281 * (same as v4wb)
282 */
283arm925_dma_inv_range:
284#ifndef CONFIG_CPU_DCACHE_WRITETHROUGH
285 tst r0, #CACHE_DLINESIZE - 1
286 mcrne p15, 0, r0, c7, c10, 1 @ clean D entry
287 tst r1, #CACHE_DLINESIZE - 1
288 mcrne p15, 0, r1, c7, c10, 1 @ clean D entry
289#endif
290 bic r0, r0, #CACHE_DLINESIZE - 1
2911: mcr p15, 0, r0, c7, c6, 1 @ invalidate D entry
292 add r0, r0, #CACHE_DLINESIZE
293 cmp r0, r1
294 blo 1b
295 mcr p15, 0, r0, c7, c10, 4 @ drain WB
296 ret lr
297
298/*
299 * dma_clean_range(start, end)
300 *
301 * Clean the specified virtual address range.
302 *
303 * - start - virtual start address
304 * - end - virtual end address
305 *
306 * (same as v4wb)
307 */
308arm925_dma_clean_range:
309#ifndef CONFIG_CPU_DCACHE_WRITETHROUGH
310 bic r0, r0, #CACHE_DLINESIZE - 1
3111: mcr p15, 0, r0, c7, c10, 1 @ clean D entry
312 add r0, r0, #CACHE_DLINESIZE
313 cmp r0, r1
314 blo 1b
315#endif
316 mcr p15, 0, r0, c7, c10, 4 @ drain WB
317 ret lr
318
319/*
320 * dma_flush_range(start, end)
321 *
322 * Clean and invalidate the specified virtual address range.
323 *
324 * - start - virtual start address
325 * - end - virtual end address
326 */
327ENTRY(arm925_dma_flush_range)
328 bic r0, r0, #CACHE_DLINESIZE - 1
3291:
330#ifndef CONFIG_CPU_DCACHE_WRITETHROUGH
331 mcr p15, 0, r0, c7, c14, 1 @ clean+invalidate D entry
332#else
333 mcr p15, 0, r0, c7, c6, 1 @ invalidate D entry
334#endif
335 add r0, r0, #CACHE_DLINESIZE
336 cmp r0, r1
337 blo 1b
338 mcr p15, 0, r0, c7, c10, 4 @ drain WB
339 ret lr
340
341/*
342 * dma_map_area(start, size, dir)
343 * - start - kernel virtual start address
344 * - size - size of region
345 * - dir - DMA direction
346 */
347ENTRY(arm925_dma_map_area)
348 add r1, r1, r0
349 cmp r2, #DMA_TO_DEVICE
350 beq arm925_dma_clean_range
351 bcs arm925_dma_inv_range
352 b arm925_dma_flush_range
353ENDPROC(arm925_dma_map_area)
354
355/*
356 * dma_unmap_area(start, size, dir)
357 * - start - kernel virtual start address
358 * - size - size of region
359 * - dir - DMA direction
360 */
361ENTRY(arm925_dma_unmap_area)
362 ret lr
363ENDPROC(arm925_dma_unmap_area)
364
365 .globl arm925_flush_kern_cache_louis
366 .equ arm925_flush_kern_cache_louis, arm925_flush_kern_cache_all
367
368 @ define struct cpu_cache_fns (see <asm/cacheflush.h> and proc-macros.S)
369 define_cache_functions arm925
370
371ENTRY(cpu_arm925_dcache_clean_area)
372#ifndef CONFIG_CPU_DCACHE_WRITETHROUGH
3731: mcr p15, 0, r0, c7, c10, 1 @ clean D entry
374 add r0, r0, #CACHE_DLINESIZE
375 subs r1, r1, #CACHE_DLINESIZE
376 bhi 1b
377#endif
378 mcr p15, 0, r0, c7, c10, 4 @ drain WB
379 ret lr
380
381/* =============================== PageTable ============================== */
382
383/*
384 * cpu_arm925_switch_mm(pgd)
385 *
386 * Set the translation base pointer to be as described by pgd.
387 *
388 * pgd: new page tables
389 */
390 .align 5
391ENTRY(cpu_arm925_switch_mm)
392#ifdef CONFIG_MMU
393 mov ip, #0
394#ifdef CONFIG_CPU_DCACHE_WRITETHROUGH
395 mcr p15, 0, ip, c7, c6, 0 @ invalidate D cache
396#else
397 /* Flush entries in bothe segments at once, see NOTE1 above */
398 mov r3, #(CACHE_DENTRIES - 1) << 4 @ 256 entries in segment
3992: mcr p15, 0, r3, c7, c14, 2 @ clean & invalidate D index
400 subs r3, r3, #1 << 4
401 bcs 2b @ entries 255 to 0
402#endif
403 mcr p15, 0, ip, c7, c5, 0 @ invalidate I cache
404 mcr p15, 0, ip, c7, c10, 4 @ drain WB
405 mcr p15, 0, r0, c2, c0, 0 @ load page table pointer
406 mcr p15, 0, ip, c8, c7, 0 @ invalidate I & D TLBs
407#endif
408 ret lr
409
410/*
411 * cpu_arm925_set_pte_ext(ptep, pte, ext)
412 *
413 * Set a PTE and flush it out
414 */
415 .align 5
416ENTRY(cpu_arm925_set_pte_ext)
417#ifdef CONFIG_MMU
418 armv3_set_pte_ext
419 mov r0, r0
420#ifndef CONFIG_CPU_DCACHE_WRITETHROUGH
421 mcr p15, 0, r0, c7, c10, 1 @ clean D entry
422#endif
423 mcr p15, 0, r0, c7, c10, 4 @ drain WB
424#endif /* CONFIG_MMU */
425 ret lr
426
427 .type __arm925_setup, #function
428__arm925_setup:
429 mov r0, #0
430
431 /* Transparent on, D-cache clean & flush mode. See NOTE2 above */
432 orr r0,r0,#1 << 1 @ transparent mode on
433 mcr p15, 0, r0, c15, c1, 0 @ write TI config register
434
435 mov r0, #0
436 mcr p15, 0, r0, c7, c7 @ invalidate I,D caches on v4
437 mcr p15, 0, r0, c7, c10, 4 @ drain write buffer on v4
438#ifdef CONFIG_MMU
439 mcr p15, 0, r0, c8, c7 @ invalidate I,D TLBs on v4
440#endif
441
442#ifdef CONFIG_CPU_DCACHE_WRITETHROUGH
443 mov r0, #4 @ disable write-back on caches explicitly
444 mcr p15, 7, r0, c15, c0, 0
445#endif
446
447 adr r5, arm925_crval
448 ldmia r5, {r5, r6}
449 mrc p15, 0, r0, c1, c0 @ get control register v4
450 bic r0, r0, r5
451 orr r0, r0, r6
452#ifdef CONFIG_CPU_CACHE_ROUND_ROBIN
453 orr r0, r0, #0x4000 @ .1.. .... .... ....
454#endif
455 ret lr
456 .size __arm925_setup, . - __arm925_setup
457
458 /*
459 * R
460 * .RVI ZFRS BLDP WCAM
461 * .011 0001 ..11 1101
462 *
463 */
464 .type arm925_crval, #object
465arm925_crval:
466 crval clear=0x00007f3f, mmuset=0x0000313d, ucset=0x00001130
467
468 __INITDATA
469 @ define struct processor (see <asm/proc-fns.h> and proc-macros.S)
470 define_processor_functions arm925, dabort=v4t_early_abort, pabort=legacy_pabort
471
472 .section ".rodata"
473
474 string cpu_arch_name, "armv4t"
475 string cpu_elf_name, "v4"
476 string cpu_arm925_name, "ARM925T"
477
478 .align
479
480 .section ".proc.info.init", "a"
481
482.macro arm925_proc_info name:req, cpu_val:req, cpu_mask:req, cpu_name:req, cache
483 .type __\name\()_proc_info,#object
484__\name\()_proc_info:
485 .long \cpu_val
486 .long \cpu_mask
487 .long PMD_TYPE_SECT | \
488 PMD_SECT_CACHEABLE | \
489 PMD_BIT4 | \
490 PMD_SECT_AP_WRITE | \
491 PMD_SECT_AP_READ
492 .long PMD_TYPE_SECT | \
493 PMD_BIT4 | \
494 PMD_SECT_AP_WRITE | \
495 PMD_SECT_AP_READ
496 initfn __arm925_setup, __\name\()_proc_info
497 .long cpu_arch_name
498 .long cpu_elf_name
499 .long HWCAP_SWP | HWCAP_HALF | HWCAP_THUMB
500 .long cpu_arm925_name
501 .long arm925_processor_functions
502 .long v4wbi_tlb_fns
503 .long v4wb_user_fns
504 .long arm925_cache_fns
505 .size __\name\()_proc_info, . - __\name\()_proc_info
506.endm
507
508 arm925_proc_info arm925, 0x54029250, 0xfffffff0, cpu_arm925_name
509 arm925_proc_info arm915, 0x54029150, 0xfffffff0, cpu_arm925_name
510

source code of linux/arch/arm/mm/proc-arm925.S