xref: /openbmc/linux/arch/arm/mm/proc-v6.S (revision bab55037) 
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 <linux/pgtable.h>
13#include <asm/assembler.h>
14#include <asm/asm-offsets.h>
15#include <asm/hwcap.h>
16#include <asm/pgtable-hwdef.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
35.arch armv6
36
37ENTRY(cpu_v6_proc_init)
38	ret	lr
39
40ENTRY(cpu_v6_proc_fin)
41	mrc	p15, 0, r0, c1, c0, 0		@ ctrl register
42	bic	r0, r0, #0x1000			@ ...i............
43	bic	r0, r0, #0x0006			@ .............ca.
44	mcr	p15, 0, r0, c1, c0, 0		@ disable caches
45	ret	lr
46
47/*
48 *	cpu_v6_reset(loc)
49 *
50 *	Perform a soft reset of the system.  Put the CPU into the
51 *	same state as it would be if it had been reset, and branch
52 *	to what would be the reset vector.
53 *
54 *	- loc   - location to jump to for soft reset
55 */
56	.align	5
57	.pushsection	.idmap.text, "ax"
58ENTRY(cpu_v6_reset)
59	mrc	p15, 0, r1, c1, c0, 0		@ ctrl register
60	bic	r1, r1, #0x1			@ ...............m
61	mcr	p15, 0, r1, c1, c0, 0		@ disable MMU
62	mov	r1, #0
63	mcr	p15, 0, r1, c7, c5, 4		@ ISB
64	ret	r0
65ENDPROC(cpu_v6_reset)
66	.popsection
67
68/*
69 *	cpu_v6_do_idle()
70 *
71 *	Idle the processor (eg, wait for interrupt).
72 *
73 *	IRQs are already disabled.
74 */
75ENTRY(cpu_v6_do_idle)
76	mov	r1, #0
77	mcr	p15, 0, r1, c7, c10, 4		@ DWB - WFI may enter a low-power mode
78	mcr	p15, 0, r1, c7, c0, 4		@ wait for interrupt
79	ret	lr
80
81ENTRY(cpu_v6_dcache_clean_area)
821:	mcr	p15, 0, r0, c7, c10, 1		@ clean D entry
83	add	r0, r0, #D_CACHE_LINE_SIZE
84	subs	r1, r1, #D_CACHE_LINE_SIZE
85	bhi	1b
86	ret	lr
87
88/*
89 *	cpu_v6_switch_mm(pgd_phys, tsk)
90 *
91 *	Set the translation table base pointer to be pgd_phys
92 *
93 *	- pgd_phys - physical address of new TTB
94 *
95 *	It is assumed that:
96 *	- we are not using split page tables
97 */
98ENTRY(cpu_v6_switch_mm)
99#ifdef CONFIG_MMU
100	mov	r2, #0
101	mmid	r1, r1				@ get mm->context.id
102	ALT_SMP(orr	r0, r0, #TTB_FLAGS_SMP)
103	ALT_UP(orr	r0, r0, #TTB_FLAGS_UP)
104	mcr	p15, 0, r2, c7, c5, 6		@ flush BTAC/BTB
105	mcr	p15, 0, r2, c7, c10, 4		@ drain write buffer
106	mcr	p15, 0, r0, c2, c0, 0		@ set TTB 0
107#ifdef CONFIG_PID_IN_CONTEXTIDR
108	mrc	p15, 0, r2, c13, c0, 1		@ read current context ID
109	bic	r2, r2, #0xff			@ extract the PID
110	and	r1, r1, #0xff
111	orr	r1, r1, r2			@ insert into new context ID
112#endif
113	mcr	p15, 0, r1, c13, c0, 1		@ set context ID
114#endif
115	ret	lr
116
117/*
118 *	cpu_v6_set_pte_ext(ptep, pte, ext)
119 *
120 *	Set a level 2 translation table entry.
121 *
122 *	- ptep  - pointer to level 2 translation table entry
123 *		  (hardware version is stored at -1024 bytes)
124 *	- pte   - PTE value to store
125 *	- ext	- value for extended PTE bits
126 */
127	armv6_mt_table cpu_v6
128
129ENTRY(cpu_v6_set_pte_ext)
130#ifdef CONFIG_MMU
131	armv6_set_pte_ext cpu_v6
132#endif
133	ret	lr
134
135/* Suspend/resume support: taken from arch/arm/mach-s3c64xx/sleep.S */
136.globl	cpu_v6_suspend_size
137.equ	cpu_v6_suspend_size, 4 * 6
138#ifdef CONFIG_ARM_CPU_SUSPEND
139ENTRY(cpu_v6_do_suspend)
140	stmfd	sp!, {r4 - r9, lr}
141	mrc	p15, 0, r4, c13, c0, 0	@ FCSE/PID
142#ifdef CONFIG_MMU
143	mrc	p15, 0, r5, c3, c0, 0	@ Domain ID
144	mrc	p15, 0, r6, c2, c0, 1	@ Translation table base 1
145#endif
146	mrc	p15, 0, r7, c1, c0, 1	@ auxiliary control register
147	mrc	p15, 0, r8, c1, c0, 2	@ co-processor access control
148	mrc	p15, 0, r9, c1, c0, 0	@ control register
149	stmia	r0, {r4 - r9}
150	ldmfd	sp!, {r4- r9, pc}
151ENDPROC(cpu_v6_do_suspend)
152
153ENTRY(cpu_v6_do_resume)
154	mov	ip, #0
155	mcr	p15, 0, ip, c7, c14, 0	@ clean+invalidate D cache
156	mcr	p15, 0, ip, c7, c5, 0	@ invalidate I cache
157	mcr	p15, 0, ip, c7, c15, 0	@ clean+invalidate cache
158	mcr	p15, 0, ip, c7, c10, 4	@ drain write buffer
159	mcr	p15, 0, ip, c13, c0, 1	@ set reserved context ID
160	ldmia	r0, {r4 - r9}
161	mcr	p15, 0, r4, c13, c0, 0	@ FCSE/PID
162#ifdef CONFIG_MMU
163	mcr	p15, 0, r5, c3, c0, 0	@ Domain ID
164	ALT_SMP(orr	r1, r1, #TTB_FLAGS_SMP)
165	ALT_UP(orr	r1, r1, #TTB_FLAGS_UP)
166	mcr	p15, 0, r1, c2, c0, 0	@ Translation table base 0
167	mcr	p15, 0, r6, c2, c0, 1	@ Translation table base 1
168	mcr	p15, 0, ip, c2, c0, 2	@ TTB control register
169#endif
170	mcr	p15, 0, r7, c1, c0, 1	@ auxiliary control register
171	mcr	p15, 0, r8, c1, c0, 2	@ co-processor access control
172	mcr	p15, 0, ip, c7, c5, 4	@ ISB
173	mov	r0, r9			@ control register
174	b	cpu_resume_mmu
175ENDPROC(cpu_v6_do_resume)
176#endif
177
178	string	cpu_v6_name, "ARMv6-compatible processor"
179
180	.align
181
182/*
183 *	__v6_setup
184 *
185 *	Initialise TLB, Caches, and MMU state ready to switch the MMU
186 *	on.  Return in r0 the new CP15 C1 control register setting.
187 *
188 *	We automatically detect if we have a Harvard cache, and use the
189 *	Harvard cache control instructions insead of the unified cache
190 *	control instructions.
191 *
192 *	This should be able to cover all ARMv6 cores.
193 *
194 *	It is assumed that:
195 *	- cache type register is implemented
196 */
197__v6_setup:
198#ifdef CONFIG_SMP
199	ALT_SMP(mrc	p15, 0, r0, c1, c0, 1)	@ Enable SMP/nAMP mode
200	ALT_UP(nop)
201	orr	r0, r0, #0x20
202	ALT_SMP(mcr	p15, 0, r0, c1, c0, 1)
203	ALT_UP(nop)
204#endif
205
206	mov	r0, #0
207	mcr	p15, 0, r0, c7, c14, 0		@ clean+invalidate D cache
208	mcr	p15, 0, r0, c7, c5, 0		@ invalidate I cache
209	mcr	p15, 0, r0, c7, c15, 0		@ clean+invalidate cache
210#ifdef CONFIG_MMU
211	mcr	p15, 0, r0, c8, c7, 0		@ invalidate I + D TLBs
212	mcr	p15, 0, r0, c2, c0, 2		@ TTB control register
213	ALT_SMP(orr	r4, r4, #TTB_FLAGS_SMP)
214	ALT_UP(orr	r4, r4, #TTB_FLAGS_UP)
215	ALT_SMP(orr	r8, r8, #TTB_FLAGS_SMP)
216	ALT_UP(orr	r8, r8, #TTB_FLAGS_UP)
217	mcr	p15, 0, r8, c2, c0, 1		@ load TTB1
218#endif /* CONFIG_MMU */
219	mcr	p15, 0, r0, c7, c10, 4		@ drain write buffer and
220						@ complete invalidations
221	adr	r5, v6_crval
222	ldmia	r5, {r5, r6}
223 ARM_BE8(orr	r6, r6, #1 << 25)		@ big-endian page tables
224	mrc	p15, 0, r0, c1, c0, 0		@ read control register
225	bic	r0, r0, r5			@ clear bits them
226	orr	r0, r0, r6			@ set them
227#ifdef CONFIG_ARM_ERRATA_364296
228	/*
229	 * Workaround for the 364296 ARM1136 r0p2 erratum (possible cache data
230	 * corruption with hit-under-miss enabled). The conditional code below
231	 * (setting the undocumented bit 31 in the auxiliary control register
232	 * and the FI bit in the control register) disables hit-under-miss
233	 * without putting the processor into full low interrupt latency mode.
234	 */
235	ldr	r6, =0x4107b362			@ id for ARM1136 r0p2
236	mrc	p15, 0, r5, c0, c0, 0		@ get processor id
237	teq	r5, r6				@ check for the faulty core
238	mrceq	p15, 0, r5, c1, c0, 1		@ load aux control reg
239	orreq	r5, r5, #(1 << 31)		@ set the undocumented bit 31
240	mcreq	p15, 0, r5, c1, c0, 1		@ write aux control reg
241	orreq	r0, r0, #(1 << 21)		@ low interrupt latency configuration
242#endif
243	ret	lr				@ return to head.S:__ret
244
245	/*
246	 *         V X F   I D LR
247	 * .... ...E PUI. .T.T 4RVI ZFRS BLDP WCAM
248	 * rrrr rrrx xxx0 0101 xxxx xxxx x111 xxxx < forced
249	 *         0 110       0011 1.00 .111 1101 < we want
250	 */
251	.type	v6_crval, #object
252v6_crval:
253	crval	clear=0x01e0fb7f, mmuset=0x00c0387d, ucset=0x00c0187c
254
255	__INITDATA
256
257	@ define struct processor (see <asm/proc-fns.h> and proc-macros.S)
258	define_processor_functions v6, dabort=v6_early_abort, pabort=v6_pabort, suspend=1
259
260	.section ".rodata"
261
262	string	cpu_arch_name, "armv6"
263	string	cpu_elf_name, "v6"
264	.align
265
266	.section ".proc.info.init", "a"
267
268	/*
269	 * Match any ARMv6 processor core.
270	 */
271	.type	__v6_proc_info, #object
272__v6_proc_info:
273	.long	0x0007b000
274	.long	0x0007f000
275	ALT_SMP(.long \
276		PMD_TYPE_SECT | \
277		PMD_SECT_AP_WRITE | \
278		PMD_SECT_AP_READ | \
279		PMD_FLAGS_SMP)
280	ALT_UP(.long \
281		PMD_TYPE_SECT | \
282		PMD_SECT_AP_WRITE | \
283		PMD_SECT_AP_READ | \
284		PMD_FLAGS_UP)
285	.long   PMD_TYPE_SECT | \
286		PMD_SECT_XN | \
287		PMD_SECT_AP_WRITE | \
288		PMD_SECT_AP_READ
289	initfn	__v6_setup, __v6_proc_info
290	.long	cpu_arch_name
291	.long	cpu_elf_name
292	/* See also feat_v6_fixup() for HWCAP_TLS */
293	.long	HWCAP_SWP|HWCAP_HALF|HWCAP_THUMB|HWCAP_FAST_MULT|HWCAP_EDSP|HWCAP_JAVA|HWCAP_TLS
294	.long	cpu_v6_name
295	.long	v6_processor_functions
296	.long	v6wbi_tlb_fns
297	.long	v6_user_fns
298	.long	v6_cache_fns
299	.size	__v6_proc_info, . - __v6_proc_info
300