1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * linux/arch/arm/mm/cache-v6.S
4 *
5 * Copyright (C) 2001 Deep Blue Solutions Ltd.
6 *
7 * This is the "shell" of the ARMv6 processor support.
8 */
9#include <linux/linkage.h>
10#include <linux/init.h>
11#include <asm/assembler.h>
12#include <asm/errno.h>
13#include <asm/unwind.h>
14
15#include "proc-macros.S"
16
17#define HARVARD_CACHE
18#define CACHE_LINE_SIZE 32
19#define D_CACHE_LINE_SIZE 32
20#define BTB_FLUSH_SIZE 8
21
22.arch armv6
23
24/*
25 * v6_flush_icache_all()
26 *
27 * Flush the whole I-cache.
28 *
29 * ARM1136 erratum 411920 - Invalidate Instruction Cache operation can fail.
30 * This erratum is present in 1136, 1156 and 1176. It does not affect the
31 * MPCore.
32 *
33 * Registers:
34 * r0 - set to 0
35 * r1 - corrupted
36 */
37ENTRY(v6_flush_icache_all)
38 mov r0, #0
39#ifdef CONFIG_ARM_ERRATA_411920
40 mrs r1, cpsr
41 cpsid ifa @ disable interrupts
42 mcr p15, 0, r0, c7, c5, 0 @ invalidate entire I-cache
43 mcr p15, 0, r0, c7, c5, 0 @ invalidate entire I-cache
44 mcr p15, 0, r0, c7, c5, 0 @ invalidate entire I-cache
45 mcr p15, 0, r0, c7, c5, 0 @ invalidate entire I-cache
46 msr cpsr_cx, r1 @ restore interrupts
47 .rept 11 @ ARM Ltd recommends at least
48 nop @ 11 NOPs
49 .endr
50#else
51 mcr p15, 0, r0, c7, c5, 0 @ invalidate I-cache
52#endif
53 ret lr
54ENDPROC(v6_flush_icache_all)
55
56/*
57 * v6_flush_cache_all()
58 *
59 * Flush the entire cache.
60 *
61 * It is assumed that:
62 */
63ENTRY(v6_flush_kern_cache_all)
64 mov r0, #0
65#ifdef HARVARD_CACHE
66 mcr p15, 0, r0, c7, c14, 0 @ D cache clean+invalidate
67#ifndef CONFIG_ARM_ERRATA_411920
68 mcr p15, 0, r0, c7, c5, 0 @ I+BTB cache invalidate
69#else
70 b v6_flush_icache_all
71#endif
72#else
73 mcr p15, 0, r0, c7, c15, 0 @ Cache clean+invalidate
74#endif
75 ret lr
76
77/*
78 * v6_flush_cache_all()
79 *
80 * Flush all TLB entries in a particular address space
81 *
82 * - mm - mm_struct describing address space
83 */
84ENTRY(v6_flush_user_cache_all)
85 /*FALLTHROUGH*/
86
87/*
88 * v6_flush_cache_range(start, end, flags)
89 *
90 * Flush a range of TLB entries in the specified address space.
91 *
92 * - start - start address (may not be aligned)
93 * - end - end address (exclusive, may not be aligned)
94 * - flags - vm_area_struct flags describing address space
95 *
96 * It is assumed that:
97 * - we have a VIPT cache.
98 */
99ENTRY(v6_flush_user_cache_range)
100 ret lr
101
102/*
103 * v6_coherent_kern_range(start,end)
104 *
105 * Ensure that the I and D caches are coherent within specified
106 * region. This is typically used when code has been written to
107 * a memory region, and will be executed.
108 *
109 * - start - virtual start address of region
110 * - end - virtual end address of region
111 *
112 * It is assumed that:
113 * - the Icache does not read data from the write buffer
114 */
115ENTRY(v6_coherent_kern_range)
116 /* FALLTHROUGH */
117
118/*
119 * v6_coherent_user_range(start,end)
120 *
121 * Ensure that the I and D caches are coherent within specified
122 * region. This is typically used when code has been written to
123 * a memory region, and will be executed.
124 *
125 * - start - virtual start address of region
126 * - end - virtual end address of region
127 *
128 * It is assumed that:
129 * - the Icache does not read data from the write buffer
130 */
131ENTRY(v6_coherent_user_range)
132 UNWIND(.fnstart )
133#ifdef HARVARD_CACHE
134 bic r0, r0, #CACHE_LINE_SIZE - 1
1351:
136 USER( mcr p15, 0, r0, c7, c10, 1 ) @ clean D line
137 add r0, r0, #CACHE_LINE_SIZE
138 cmp r0, r1
139 blo 1b
140#endif
141 mov r0, #0
142#ifdef HARVARD_CACHE
143 mcr p15, 0, r0, c7, c10, 4 @ drain write buffer
144#ifndef CONFIG_ARM_ERRATA_411920
145 mcr p15, 0, r0, c7, c5, 0 @ I+BTB cache invalidate
146#else
147 b v6_flush_icache_all
148#endif
149#else
150 mcr p15, 0, r0, c7, c5, 6 @ invalidate BTB
151#endif
152 ret lr
153
154/*
155 * Fault handling for the cache operation above. If the virtual address in r0
156 * isn't mapped, fail with -EFAULT.
157 */
1589001:
159 mov r0, #-EFAULT
160 ret lr
161 UNWIND(.fnend )
162ENDPROC(v6_coherent_user_range)
163ENDPROC(v6_coherent_kern_range)
164
165/*
166 * v6_flush_kern_dcache_area(void *addr, size_t size)
167 *
168 * Ensure that the data held in the page kaddr is written back
169 * to the page in question.
170 *
171 * - addr - kernel address
172 * - size - region size
173 */
174ENTRY(v6_flush_kern_dcache_area)
175 add r1, r0, r1
176 bic r0, r0, #D_CACHE_LINE_SIZE - 1
1771:
178#ifdef HARVARD_CACHE
179 mcr p15, 0, r0, c7, c14, 1 @ clean & invalidate D line
180#else
181 mcr p15, 0, r0, c7, c15, 1 @ clean & invalidate unified line
182#endif
183 add r0, r0, #D_CACHE_LINE_SIZE
184 cmp r0, r1
185 blo 1b
186#ifdef HARVARD_CACHE
187 mov r0, #0
188 mcr p15, 0, r0, c7, c10, 4
189#endif
190 ret lr
191
192
193/*
194 * v6_dma_inv_range(start,end)
195 *
196 * Invalidate the data cache within the specified region; we will
197 * be performing a DMA operation in this region and we want to
198 * purge old data in the cache.
199 *
200 * - start - virtual start address of region
201 * - end - virtual end address of region
202 */
203v6_dma_inv_range:
204 tst r0, #D_CACHE_LINE_SIZE - 1
205 bic r0, r0, #D_CACHE_LINE_SIZE - 1
206#ifdef HARVARD_CACHE
207 mcrne p15, 0, r0, c7, c10, 1 @ clean D line
208#else
209 mcrne p15, 0, r0, c7, c11, 1 @ clean unified line
210#endif
211 tst r1, #D_CACHE_LINE_SIZE - 1
212 bic r1, r1, #D_CACHE_LINE_SIZE - 1
213#ifdef HARVARD_CACHE
214 mcrne p15, 0, r1, c7, c14, 1 @ clean & invalidate D line
215#else
216 mcrne p15, 0, r1, c7, c15, 1 @ clean & invalidate unified line
217#endif
2181:
219#ifdef HARVARD_CACHE
220 mcr p15, 0, r0, c7, c6, 1 @ invalidate D line
221#else
222 mcr p15, 0, r0, c7, c7, 1 @ invalidate unified line
223#endif
224 add r0, r0, #D_CACHE_LINE_SIZE
225 cmp r0, r1
226 blo 1b
227 mov r0, #0
228 mcr p15, 0, r0, c7, c10, 4 @ drain write buffer
229 ret lr
230
231/*
232 * v6_dma_clean_range(start,end)
233 * - start - virtual start address of region
234 * - end - virtual end address of region
235 */
236v6_dma_clean_range:
237 bic r0, r0, #D_CACHE_LINE_SIZE - 1
2381:
239#ifdef HARVARD_CACHE
240 mcr p15, 0, r0, c7, c10, 1 @ clean D line
241#else
242 mcr p15, 0, r0, c7, c11, 1 @ clean unified line
243#endif
244 add r0, r0, #D_CACHE_LINE_SIZE
245 cmp r0, r1
246 blo 1b
247 mov r0, #0
248 mcr p15, 0, r0, c7, c10, 4 @ drain write buffer
249 ret lr
250
251/*
252 * v6_dma_flush_range(start,end)
253 * - start - virtual start address of region
254 * - end - virtual end address of region
255 */
256ENTRY(v6_dma_flush_range)
257 bic r0, r0, #D_CACHE_LINE_SIZE - 1
2581:
259#ifdef HARVARD_CACHE
260 mcr p15, 0, r0, c7, c14, 1 @ clean & invalidate D line
261#else
262 mcr p15, 0, r0, c7, c15, 1 @ clean & invalidate line
263#endif
264 add r0, r0, #D_CACHE_LINE_SIZE
265 cmp r0, r1
266 blo 1b
267 mov r0, #0
268 mcr p15, 0, r0, c7, c10, 4 @ drain write buffer
269 ret lr
270
271/*
272 * dma_map_area(start, size, dir)
273 * - start - kernel virtual start address
274 * - size - size of region
275 * - dir - DMA direction
276 */
277ENTRY(v6_dma_map_area)
278 add r1, r1, r0
279 teq r2, #DMA_FROM_DEVICE
280 beq v6_dma_inv_range
281 b v6_dma_clean_range
282ENDPROC(v6_dma_map_area)
283
284/*
285 * dma_unmap_area(start, size, dir)
286 * - start - kernel virtual start address
287 * - size - size of region
288 * - dir - DMA direction
289 */
290ENTRY(v6_dma_unmap_area)
291 add r1, r1, r0
292 teq r2, #DMA_TO_DEVICE
293 bne v6_dma_inv_range
294 ret lr
295ENDPROC(v6_dma_unmap_area)
296
297 .globl v6_flush_kern_cache_louis
298 .equ v6_flush_kern_cache_louis, v6_flush_kern_cache_all
299
300 __INITDATA
301
302 @ define struct cpu_cache_fns (see <asm/cacheflush.h> and proc-macros.S)
303 define_cache_functions v6
304

source code of linux/arch/arm/mm/cache-v6.S