xref: /openbmc/linux/arch/arm/mm/proc-v6.S (revision f125e2d4) 
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/linkage.h>
12#include <asm/assembler.h>
13#include <asm/asm-offsets.h>
14#include <asm/hwcap.h>
15#include <asm/pgtable-hwdef.h>
16#include <asm/pgtable.h>
17
18#include "proc-macros.S"
19
20#define D_CACHE_LINE_SIZE	32
21
22#define TTB_C		(1 << 0)
23#define TTB_S		(1 << 1)
24#define TTB_IMP		(1 << 2)
25#define TTB_RGN_NC	(0 << 3)
26#define TTB_RGN_WBWA	(1 << 3)
27#define TTB_RGN_WT	(2 << 3)
28#define TTB_RGN_WB	(3 << 3)
29
30#define TTB_FLAGS_UP	TTB_RGN_WBWA
31#define PMD_FLAGS_UP	PMD_SECT_WB
32#define TTB_FLAGS_SMP	TTB_RGN_WBWA|TTB_S
33#define PMD_FLAGS_SMP	PMD_SECT_WBWA|PMD_SECT_S
34
35ENTRY(cpu_v6_proc_init)
36	ret	lr
37
38ENTRY(cpu_v6_proc_fin)
39	mrc	p15, 0, r0, c1, c0, 0		@ ctrl register
40	bic	r0, r0, #0x1000			@ ...i............
41	bic	r0, r0, #0x0006			@ .............ca.
42	mcr	p15, 0, r0, c1, c0, 0		@ disable caches
43	ret	lr
44
45/*
46 *	cpu_v6_reset(loc)
47 *
48 *	Perform a soft reset of the system.  Put the CPU into the
49 *	same state as it would be if it had been reset, and branch
50 *	to what would be the reset vector.
51 *
52 *	- loc   - location to jump to for soft reset
53 */
54	.align	5
55	.pushsection	.idmap.text, "ax"
56ENTRY(cpu_v6_reset)
57	mrc	p15, 0, r1, c1, c0, 0		@ ctrl register
58	bic	r1, r1, #0x1			@ ...............m
59	mcr	p15, 0, r1, c1, c0, 0		@ disable MMU
60	mov	r1, #0
61	mcr	p15, 0, r1, c7, c5, 4		@ ISB
62	ret	r0
63ENDPROC(cpu_v6_reset)
64	.popsection
65
66/*
67 *	cpu_v6_do_idle()
68 *
69 *	Idle the processor (eg, wait for interrupt).
70 *
71 *	IRQs are already disabled.
72 */
73ENTRY(cpu_v6_do_idle)
74	mov	r1, #0
75	mcr	p15, 0, r1, c7, c10, 4		@ DWB - WFI may enter a low-power mode
76	mcr	p15, 0, r1, c7, c0, 4		@ wait for interrupt
77	ret	lr
78
79ENTRY(cpu_v6_dcache_clean_area)
801:	mcr	p15, 0, r0, c7, c10, 1		@ clean D entry
81	add	r0, r0, #D_CACHE_LINE_SIZE
82	subs	r1, r1, #D_CACHE_LINE_SIZE
83	bhi	1b
84	ret	lr
85
86/*
87 *	cpu_v6_switch_mm(pgd_phys, tsk)
88 *
89 *	Set the translation table base pointer to be pgd_phys
90 *
91 *	- pgd_phys - physical address of new TTB
92 *
93 *	It is assumed that:
94 *	- we are not using split page tables
95 */
96ENTRY(cpu_v6_switch_mm)
97#ifdef CONFIG_MMU
98	mov	r2, #0
99	mmid	r1, r1				@ get mm->context.id
100	ALT_SMP(orr	r0, r0, #TTB_FLAGS_SMP)
101	ALT_UP(orr	r0, r0, #TTB_FLAGS_UP)
102	mcr	p15, 0, r2, c7, c5, 6		@ flush BTAC/BTB
103	mcr	p15, 0, r2, c7, c10, 4		@ drain write buffer
104	mcr	p15, 0, r0, c2, c0, 0		@ set TTB 0
105#ifdef CONFIG_PID_IN_CONTEXTIDR
106	mrc	p15, 0, r2, c13, c0, 1		@ read current context ID
107	bic	r2, r2, #0xff			@ extract the PID
108	and	r1, r1, #0xff
109	orr	r1, r1, r2			@ insert into new context ID
110#endif
111	mcr	p15, 0, r1, c13, c0, 1		@ set context ID
112#endif
113	ret	lr
114
115/*
116 *	cpu_v6_set_pte_ext(ptep, pte, ext)
117 *
118 *	Set a level 2 translation table entry.
119 *
120 *	- ptep  - pointer to level 2 translation table entry
121 *		  (hardware version is stored at -1024 bytes)
122 *	- pte   - PTE value to store
123 *	- ext	- value for extended PTE bits
124 */
125	armv6_mt_table cpu_v6
126
127ENTRY(cpu_v6_set_pte_ext)
128#ifdef CONFIG_MMU
129	armv6_set_pte_ext cpu_v6
130#endif
131	ret	lr
132
133/* Suspend/resume support: taken from arch/arm/mach-s3c64xx/sleep.S */
134.globl	cpu_v6_suspend_size
135.equ	cpu_v6_suspend_size, 4 * 6
136#ifdef CONFIG_ARM_CPU_SUSPEND
137ENTRY(cpu_v6_do_suspend)
138	stmfd	sp!, {r4 - r9, lr}
139	mrc	p15, 0, r4, c13, c0, 0	@ FCSE/PID
140#ifdef CONFIG_MMU
141	mrc	p15, 0, r5, c3, c0, 0	@ Domain ID
142	mrc	p15, 0, r6, c2, c0, 1	@ Translation table base 1
143#endif
144	mrc	p15, 0, r7, c1, c0, 1	@ auxiliary control register
145	mrc	p15, 0, r8, c1, c0, 2	@ co-processor access control
146	mrc	p15, 0, r9, c1, c0, 0	@ control register
147	stmia	r0, {r4 - r9}
148	ldmfd	sp!, {r4- r9, pc}
149ENDPROC(cpu_v6_do_suspend)
150
151ENTRY(cpu_v6_do_resume)
152	mov	ip, #0
153	mcr	p15, 0, ip, c7, c14, 0	@ clean+invalidate D cache
154	mcr	p15, 0, ip, c7, c5, 0	@ invalidate I cache
155	mcr	p15, 0, ip, c7, c15, 0	@ clean+invalidate cache
156	mcr	p15, 0, ip, c7, c10, 4	@ drain write buffer
157	mcr	p15, 0, ip, c13, c0, 1	@ set reserved context ID
158	ldmia	r0, {r4 - r9}
159	mcr	p15, 0, r4, c13, c0, 0	@ FCSE/PID
160#ifdef CONFIG_MMU
161	mcr	p15, 0, r5, c3, c0, 0	@ Domain ID
162	ALT_SMP(orr	r1, r1, #TTB_FLAGS_SMP)
163	ALT_UP(orr	r1, r1, #TTB_FLAGS_UP)
164	mcr	p15, 0, r1, c2, c0, 0	@ Translation table base 0
165	mcr	p15, 0, r6, c2, c0, 1	@ Translation table base 1
166	mcr	p15, 0, ip, c2, c0, 2	@ TTB control register
167#endif
168	mcr	p15, 0, r7, c1, c0, 1	@ auxiliary control register
169	mcr	p15, 0, r8, c1, c0, 2	@ co-processor access control
170	mcr	p15, 0, ip, c7, c5, 4	@ ISB
171	mov	r0, r9			@ control register
172	b	cpu_resume_mmu
173ENDPROC(cpu_v6_do_resume)
174#endif
175
176	string	cpu_v6_name, "ARMv6-compatible processor"
177
178	.align
179
180/*
181 *	__v6_setup
182 *
183 *	Initialise TLB, Caches, and MMU state ready to switch the MMU
184 *	on.  Return in r0 the new CP15 C1 control register setting.
185 *
186 *	We automatically detect if we have a Harvard cache, and use the
187 *	Harvard cache control instructions insead of the unified cache
188 *	control instructions.
189 *
190 *	This should be able to cover all ARMv6 cores.
191 *
192 *	It is assumed that:
193 *	- cache type register is implemented
194 */
195__v6_setup:
196#ifdef CONFIG_SMP
197	ALT_SMP(mrc	p15, 0, r0, c1, c0, 1)	@ Enable SMP/nAMP mode
198	ALT_UP(nop)
199	orr	r0, r0, #0x20
200	ALT_SMP(mcr	p15, 0, r0, c1, c0, 1)
201	ALT_UP(nop)
202#endif
203
204	mov	r0, #0
205	mcr	p15, 0, r0, c7, c14, 0		@ clean+invalidate D cache
206	mcr	p15, 0, r0, c7, c5, 0		@ invalidate I cache
207	mcr	p15, 0, r0, c7, c15, 0		@ clean+invalidate cache
208#ifdef CONFIG_MMU
209	mcr	p15, 0, r0, c8, c7, 0		@ invalidate I + D TLBs
210	mcr	p15, 0, r0, c2, c0, 2		@ TTB control register
211	ALT_SMP(orr	r4, r4, #TTB_FLAGS_SMP)
212	ALT_UP(orr	r4, r4, #TTB_FLAGS_UP)
213	ALT_SMP(orr	r8, r8, #TTB_FLAGS_SMP)
214	ALT_UP(orr	r8, r8, #TTB_FLAGS_UP)
215	mcr	p15, 0, r8, c2, c0, 1		@ load TTB1
216#endif /* CONFIG_MMU */
217	mcr	p15, 0, r0, c7, c10, 4		@ drain write buffer and
218						@ complete invalidations
219	adr	r5, v6_crval
220	ldmia	r5, {r5, r6}
221 ARM_BE8(orr	r6, r6, #1 << 25)		@ big-endian page tables
222	mrc	p15, 0, r0, c1, c0, 0		@ read control register
223	bic	r0, r0, r5			@ clear bits them
224	orr	r0, r0, r6			@ set them
225#ifdef CONFIG_ARM_ERRATA_364296
226	/*
227	 * Workaround for the 364296 ARM1136 r0p2 erratum (possible cache data
228	 * corruption with hit-under-miss enabled). The conditional code below
229	 * (setting the undocumented bit 31 in the auxiliary control register
230	 * and the FI bit in the control register) disables hit-under-miss
231	 * without putting the processor into full low interrupt latency mode.
232	 */
233	ldr	r6, =0x4107b362			@ id for ARM1136 r0p2
234	mrc	p15, 0, r5, c0, c0, 0		@ get processor id
235	teq	r5, r6				@ check for the faulty core
236	mrceq	p15, 0, r5, c1, c0, 1		@ load aux control reg
237	orreq	r5, r5, #(1 << 31)		@ set the undocumented bit 31
238	mcreq	p15, 0, r5, c1, c0, 1		@ write aux control reg
239	orreq	r0, r0, #(1 << 21)		@ low interrupt latency configuration
240#endif
241	ret	lr				@ return to head.S:__ret
242
243	/*
244	 *         V X F   I D LR
245	 * .... ...E PUI. .T.T 4RVI ZFRS BLDP WCAM
246	 * rrrr rrrx xxx0 0101 xxxx xxxx x111 xxxx < forced
247	 *         0 110       0011 1.00 .111 1101 < we want
248	 */
249	.type	v6_crval, #object
250v6_crval:
251	crval	clear=0x01e0fb7f, mmuset=0x00c0387d, ucset=0x00c0187c
252
253	__INITDATA
254
255	@ define struct processor (see <asm/proc-fns.h> and proc-macros.S)
256	define_processor_functions v6, dabort=v6_early_abort, pabort=v6_pabort, suspend=1
257
258	.section ".rodata"
259
260	string	cpu_arch_name, "armv6"
261	string	cpu_elf_name, "v6"
262	.align
263
264	.section ".proc.info.init", "a"
265
266	/*
267	 * Match any ARMv6 processor core.
268	 */
269	.type	__v6_proc_info, #object
270__v6_proc_info:
271	.long	0x0007b000
272	.long	0x0007f000
273	ALT_SMP(.long \
274		PMD_TYPE_SECT | \
275		PMD_SECT_AP_WRITE | \
276		PMD_SECT_AP_READ | \
277		PMD_FLAGS_SMP)
278	ALT_UP(.long \
279		PMD_TYPE_SECT | \
280		PMD_SECT_AP_WRITE | \
281		PMD_SECT_AP_READ | \
282		PMD_FLAGS_UP)
283	.long   PMD_TYPE_SECT | \
284		PMD_SECT_XN | \
285		PMD_SECT_AP_WRITE | \
286		PMD_SECT_AP_READ
287	initfn	__v6_setup, __v6_proc_info
288	.long	cpu_arch_name
289	.long	cpu_elf_name
290	/* See also feat_v6_fixup() for HWCAP_TLS */
291	.long	HWCAP_SWP|HWCAP_HALF|HWCAP_THUMB|HWCAP_FAST_MULT|HWCAP_EDSP|HWCAP_JAVA|HWCAP_TLS
292	.long	cpu_v6_name
293	.long	v6_processor_functions
294	.long	v6wbi_tlb_fns
295	.long	v6_user_fns
296	.long	v6_cache_fns
297	.size	__v6_proc_info, . - __v6_proc_info
298