xref: /linux/arch/arm/mm/proc-v6.S (revision 20dfee95936413708701eb151f419597fdd9d948) 
1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 *  linux/arch/arm/mm/proc-v6.S
4 *
5 *  Copyright (C) 2001 Deep Blue Solutions Ltd.
6 *  Modified by Catalin Marinas for noMMU support
7 *
8 *  This is the "shell" of the ARMv6 processor support.
9 */
10#include <linux/init.h>
11#include <linux/cfi_types.h>
12#include <linux/linkage.h>
13#include <linux/pgtable.h>
14#include <asm/assembler.h>
15#include <asm/asm-offsets.h>
16#include <asm/hwcap.h>
17#include <asm/pgtable-hwdef.h>
18
19#include "proc-macros.S"
20
21#define D_CACHE_LINE_SIZE	32
22
23#define TTB_C		(1 << 0)
24#define TTB_S		(1 << 1)
25#define TTB_IMP		(1 << 2)
26#define TTB_RGN_NC	(0 << 3)
27#define TTB_RGN_WBWA	(1 << 3)
28#define TTB_RGN_WT	(2 << 3)
29#define TTB_RGN_WB	(3 << 3)
30
31#define TTB_FLAGS_UP	TTB_RGN_WBWA
32#define PMD_FLAGS_UP	PMD_SECT_WB
33#define TTB_FLAGS_SMP	TTB_RGN_WBWA|TTB_S
34#define PMD_FLAGS_SMP	PMD_SECT_WBWA|PMD_SECT_S
35
36.arch armv6
37
38SYM_TYPED_FUNC_START(cpu_v6_proc_init)
39	ret	lr
40SYM_FUNC_END(cpu_v6_proc_init)
41
42SYM_TYPED_FUNC_START(cpu_v6_proc_fin)
43	mrc	p15, 0, r0, c1, c0, 0		@ ctrl register
44	bic	r0, r0, #0x1000			@ ...i............
45	bic	r0, r0, #0x0006			@ .............ca.
46	mcr	p15, 0, r0, c1, c0, 0		@ disable caches
47	ret	lr
48SYM_FUNC_END(cpu_v6_proc_fin)
49
50/*
51 *	cpu_v6_reset(loc)
52 *
53 *	Perform a soft reset of the system.  Put the CPU into the
54 *	same state as it would be if it had been reset, and branch
55 *	to what would be the reset vector.
56 *
57 *	- loc   - location to jump to for soft reset
58 */
59	.align	5
60	.pushsection	.idmap.text, "ax"
61SYM_TYPED_FUNC_START(cpu_v6_reset)
62	mrc	p15, 0, r1, c1, c0, 0		@ ctrl register
63	bic	r1, r1, #0x1			@ ...............m
64	mcr	p15, 0, r1, c1, c0, 0		@ disable MMU
65	mov	r1, #0
66	mcr	p15, 0, r1, c7, c5, 4		@ ISB
67	ret	r0
68SYM_FUNC_END(cpu_v6_reset)
69	.popsection
70
71/*
72 *	cpu_v6_do_idle()
73 *
74 *	Idle the processor (eg, wait for interrupt).
75 *
76 *	IRQs are already disabled.
77 */
78SYM_TYPED_FUNC_START(cpu_v6_do_idle)
79	mov	r1, #0
80	mcr	p15, 0, r1, c7, c10, 4		@ DWB - WFI may enter a low-power mode
81	mcr	p15, 0, r1, c7, c0, 4		@ wait for interrupt
82	ret	lr
83SYM_FUNC_END(cpu_v6_do_idle)
84
85SYM_TYPED_FUNC_START(cpu_v6_dcache_clean_area)
861:	mcr	p15, 0, r0, c7, c10, 1		@ clean D entry
87	add	r0, r0, #D_CACHE_LINE_SIZE
88	subs	r1, r1, #D_CACHE_LINE_SIZE
89	bhi	1b
90	ret	lr
91SYM_FUNC_END(cpu_v6_dcache_clean_area)
92
93/*
94 *	cpu_v6_switch_mm(pgd_phys, tsk)
95 *
96 *	Set the translation table base pointer to be pgd_phys
97 *
98 *	- pgd_phys - physical address of new TTB
99 *
100 *	It is assumed that:
101 *	- we are not using split page tables
102 */
103SYM_TYPED_FUNC_START(cpu_v6_switch_mm)
104#ifdef CONFIG_MMU
105	mov	r2, #0
106	mmid	r1, r1				@ get mm->context.id
107	ALT_SMP(orr	r0, r0, #TTB_FLAGS_SMP)
108	ALT_UP(orr	r0, r0, #TTB_FLAGS_UP)
109	mcr	p15, 0, r2, c7, c5, 6		@ flush BTAC/BTB
110	mcr	p15, 0, r2, c7, c10, 4		@ drain write buffer
111	mcr	p15, 0, r0, c2, c0, 0		@ set TTB 0
112#ifdef CONFIG_PID_IN_CONTEXTIDR
113	mrc	p15, 0, r2, c13, c0, 1		@ read current context ID
114	bic	r2, r2, #0xff			@ extract the PID
115	and	r1, r1, #0xff
116	orr	r1, r1, r2			@ insert into new context ID
117#endif
118	mcr	p15, 0, r1, c13, c0, 1		@ set context ID
119#endif
120	ret	lr
121SYM_FUNC_END(cpu_v6_switch_mm)
122
123/*
124 *	cpu_v6_set_pte_ext(ptep, pte, ext)
125 *
126 *	Set a level 2 translation table entry.
127 *
128 *	- ptep  - pointer to level 2 translation table entry
129 *		  (hardware version is stored at -1024 bytes)
130 *	- pte   - PTE value to store
131 *	- ext	- value for extended PTE bits
132 */
133	armv6_mt_table cpu_v6
134
135SYM_TYPED_FUNC_START(cpu_v6_set_pte_ext)
136#ifdef CONFIG_MMU
137	armv6_set_pte_ext cpu_v6
138#endif
139	ret	lr
140SYM_FUNC_END(cpu_v6_set_pte_ext)
141
142/* Suspend/resume support: taken from arch/arm/mach-s3c64xx/sleep.S */
143.globl	cpu_v6_suspend_size
144.equ	cpu_v6_suspend_size, 4 * 6
145#ifdef CONFIG_ARM_CPU_SUSPEND
146SYM_TYPED_FUNC_START(cpu_v6_do_suspend)
147	stmfd	sp!, {r4 - r9, lr}
148	mrc	p15, 0, r4, c13, c0, 0	@ FCSE/PID
149#ifdef CONFIG_MMU
150	mrc	p15, 0, r5, c3, c0, 0	@ Domain ID
151	mrc	p15, 0, r6, c2, c0, 1	@ Translation table base 1
152#endif
153	mrc	p15, 0, r7, c1, c0, 1	@ auxiliary control register
154	mrc	p15, 0, r8, c1, c0, 2	@ co-processor access control
155	mrc	p15, 0, r9, c1, c0, 0	@ control register
156	stmia	r0, {r4 - r9}
157	ldmfd	sp!, {r4- r9, pc}
158SYM_FUNC_END(cpu_v6_do_suspend)
159
160SYM_TYPED_FUNC_START(cpu_v6_do_resume)
161	mov	ip, #0
162	mcr	p15, 0, ip, c7, c14, 0	@ clean+invalidate D cache
163	mcr	p15, 0, ip, c7, c5, 0	@ invalidate I cache
164	mcr	p15, 0, ip, c7, c15, 0	@ clean+invalidate cache
165	mcr	p15, 0, ip, c7, c10, 4	@ drain write buffer
166	mcr	p15, 0, ip, c13, c0, 1	@ set reserved context ID
167	ldmia	r0, {r4 - r9}
168	mcr	p15, 0, r4, c13, c0, 0	@ FCSE/PID
169#ifdef CONFIG_MMU
170	mcr	p15, 0, r5, c3, c0, 0	@ Domain ID
171	ALT_SMP(orr	r1, r1, #TTB_FLAGS_SMP)
172	ALT_UP(orr	r1, r1, #TTB_FLAGS_UP)
173	mcr	p15, 0, r1, c2, c0, 0	@ Translation table base 0
174	mcr	p15, 0, r6, c2, c0, 1	@ Translation table base 1
175	mcr	p15, 0, ip, c2, c0, 2	@ TTB control register
176#endif
177	mcr	p15, 0, r7, c1, c0, 1	@ auxiliary control register
178	mcr	p15, 0, r8, c1, c0, 2	@ co-processor access control
179	mcr	p15, 0, ip, c7, c5, 4	@ ISB
180	mov	r0, r9			@ control register
181	b	cpu_resume_mmu
182SYM_FUNC_END(cpu_v6_do_resume)
183#endif
184
185	string	cpu_v6_name, "ARMv6-compatible processor"
186
187	.align
188
189/*
190 *	__v6_setup
191 *
192 *	Initialise TLB, Caches, and MMU state ready to switch the MMU
193 *	on.  Return in r0 the new CP15 C1 control register setting.
194 *
195 *	We automatically detect if we have a Harvard cache, and use the
196 *	Harvard cache control instructions insead of the unified cache
197 *	control instructions.
198 *
199 *	This should be able to cover all ARMv6 cores.
200 *
201 *	It is assumed that:
202 *	- cache type register is implemented
203 */
204__v6_setup:
205#ifdef CONFIG_SMP
206	ALT_SMP(mrc	p15, 0, r0, c1, c0, 1)	@ Enable SMP/nAMP mode
207	ALT_UP(nop)
208	orr	r0, r0, #0x20
209	ALT_SMP(mcr	p15, 0, r0, c1, c0, 1)
210	ALT_UP(nop)
211#endif
212
213	mov	r0, #0
214	mcr	p15, 0, r0, c7, c14, 0		@ clean+invalidate D cache
215	mcr	p15, 0, r0, c7, c5, 0		@ invalidate I cache
216	mcr	p15, 0, r0, c7, c15, 0		@ clean+invalidate cache
217#ifdef CONFIG_MMU
218	mcr	p15, 0, r0, c8, c7, 0		@ invalidate I + D TLBs
219	mcr	p15, 0, r0, c2, c0, 2		@ TTB control register
220	ALT_SMP(orr	r4, r4, #TTB_FLAGS_SMP)
221	ALT_UP(orr	r4, r4, #TTB_FLAGS_UP)
222	ALT_SMP(orr	r8, r8, #TTB_FLAGS_SMP)
223	ALT_UP(orr	r8, r8, #TTB_FLAGS_UP)
224	mcr	p15, 0, r8, c2, c0, 1		@ load TTB1
225#endif /* CONFIG_MMU */
226	mcr	p15, 0, r0, c7, c10, 4		@ drain write buffer and
227						@ complete invalidations
228	adr	r5, v6_crval
229	ldmia	r5, {r5, r6}
230 ARM_BE8(orr	r6, r6, #1 << 25)		@ big-endian page tables
231	mrc	p15, 0, r0, c1, c0, 0		@ read control register
232	bic	r0, r0, r5			@ clear bits them
233	orr	r0, r0, r6			@ set them
234#ifdef CONFIG_ARM_ERRATA_364296
235	/*
236	 * Workaround for the 364296 ARM1136 r0p2 erratum (possible cache data
237	 * corruption with hit-under-miss enabled). The conditional code below
238	 * (setting the undocumented bit 31 in the auxiliary control register
239	 * and the FI bit in the control register) disables hit-under-miss
240	 * without putting the processor into full low interrupt latency mode.
241	 */
242	ldr	r6, =0x4107b362			@ id for ARM1136 r0p2
243	mrc	p15, 0, r5, c0, c0, 0		@ get processor id
244	teq	r5, r6				@ check for the faulty core
245	mrceq	p15, 0, r5, c1, c0, 1		@ load aux control reg
246	orreq	r5, r5, #(1 << 31)		@ set the undocumented bit 31
247	mcreq	p15, 0, r5, c1, c0, 1		@ write aux control reg
248	orreq	r0, r0, #(1 << 21)		@ low interrupt latency configuration
249#endif
250	ret	lr				@ return to head.S:__ret
251
252	/*
253	 *         V X F   I D LR
254	 * .... ...E PUI. .T.T 4RVI ZFRS BLDP WCAM
255	 * rrrr rrrx xxx0 0101 xxxx xxxx x111 xxxx < forced
256	 *         0 110       0011 1.00 .111 1101 < we want
257	 */
258	.type	v6_crval, #object
259v6_crval:
260	crval	clear=0x01e0fb7f, mmuset=0x00c0387d, ucset=0x00c0187c
261
262	__INITDATA
263
264	@ define struct processor (see <asm/proc-fns.h> and proc-macros.S)
265	define_processor_functions v6, dabort=v6_early_abort, pabort=v6_pabort, suspend=1
266
267	.section ".rodata"
268
269	string	cpu_arch_name, "armv6"
270	string	cpu_elf_name, "v6"
271	.align
272
273	.section ".proc.info.init", "a"
274
275	/*
276	 * Match any ARMv6 processor core.
277	 */
278	.type	__v6_proc_info, #object
279__v6_proc_info:
280	.long	0x0007b000
281	.long	0x0007f000
282	ALT_SMP(.long \
283		PMD_TYPE_SECT | \
284		PMD_SECT_AP_WRITE | \
285		PMD_SECT_AP_READ | \
286		PMD_FLAGS_SMP)
287	ALT_UP(.long \
288		PMD_TYPE_SECT | \
289		PMD_SECT_AP_WRITE | \
290		PMD_SECT_AP_READ | \
291		PMD_FLAGS_UP)
292	.long   PMD_TYPE_SECT | \
293		PMD_SECT_XN | \
294		PMD_SECT_AP_WRITE | \
295		PMD_SECT_AP_READ
296	initfn	__v6_setup, __v6_proc_info
297	.long	cpu_arch_name
298	.long	cpu_elf_name
299	/* See also feat_v6_fixup() for HWCAP_TLS */
300	.long	HWCAP_SWP|HWCAP_HALF|HWCAP_THUMB|HWCAP_FAST_MULT|HWCAP_EDSP|HWCAP_JAVA|HWCAP_TLS
301	.long	cpu_v6_name
302	.long	v6_processor_functions
303	.long	v6wbi_tlb_fns
304	.long	v6_user_fns
305	.long	v6_cache_fns
306	.size	__v6_proc_info, . - __v6_proc_info
307