[mirror_ubuntu-kernels.git] / arch / arm / kernel / head-common.S

/*
 *  linux/arch/arm/kernel/head-common.S
 *
 *  Copyright (C) 1994-2002 Russell King
 *  Copyright (c) 2003 ARM Limited
 *  All Rights Reserved
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 */

#define ATAG_CORE 0x54410001
#define ATAG_CORE_SIZE ((2*4 + 3*4) >> 2)

	.type	__switch_data, %object
__switch_data:
	.long	__mmap_switched
	.long	__data_loc			@ r4
	.long	__data_start			@ r5
	.long	__bss_start			@ r6
	.long	_end				@ r7
	.long	processor_id			@ r4
	.long	__machine_arch_type		@ r5
	.long	__atags_pointer			@ r6
	.long	cr_alignment			@ r7
	.long	init_thread_union + THREAD_START_SP @ sp

/*
 * The following fragment of code is executed with the MMU on in MMU mode,
 * and uses absolute addresses; this is not position independent.
 *
 *  r0  = cp#15 control register
 *  r1  = machine ID
 *  r2  = atags pointer
 *  r9  = processor ID
 */
	.type	__mmap_switched, %function
__mmap_switched:
	adr	r3, __switch_data + 4

	ldmia	r3!, {r4, r5, r6, r7}
	cmp	r4, r5				@ Copy data segment if needed
1:	cmpne	r5, r6
	ldrne	fp, [r4], #4
	strne	fp, [r5], #4
	bne	1b

	mov	fp, #0				@ Clear BSS (and zero fp)
1:	cmp	r6, r7
	strcc	fp, [r6],#4
	bcc	1b

	ldmia	r3, {r4, r5, r6, r7, sp}
	str	r9, [r4]			@ Save processor ID
	str	r1, [r5]			@ Save machine type
	str	r2, [r6]			@ Save atags pointer
	bic	r4, r0, #CR_A			@ Clear 'A' bit
	stmia	r7, {r0, r4}			@ Save control register values
	b	start_kernel

/*
 * Exception handling.  Something went wrong and we can't proceed.  We
 * ought to tell the user, but since we don't have any guarantee that
 * we're even running on the right architecture, we do virtually nothing.
 *
 * If CONFIG_DEBUG_LL is set we try to print out something about the error
 * and hope for the best (useful if bootloader fails to pass a proper
 * machine ID for example).
 */

	.type	__error_p, %function
__error_p:
#ifdef CONFIG_DEBUG_LL
	adr	r0, str_p1
	bl	printascii
	b	__error
str_p1:	.asciz	"\nError: unrecognized/unsupported processor variant.\n"
	.align
#endif

	.type	__error_a, %function
__error_a:
#ifdef CONFIG_DEBUG_LL
	mov	r4, r1				@ preserve machine ID
	adr	r0, str_a1
	bl	printascii
	mov	r0, r4
	bl	printhex8
	adr	r0, str_a2
	bl	printascii
	adr	r3, 3f
	ldmia	r3, {r4, r5, r6}		@ get machine desc list
	sub	r4, r3, r4			@ get offset between virt&phys
	add	r5, r5, r4			@ convert virt addresses to
	add	r6, r6, r4			@ physical address space
1:	ldr	r0, [r5, #MACHINFO_TYPE]	@ get machine type
	bl	printhex8
	mov	r0, #'\t'
	bl	printch
	ldr     r0, [r5, #MACHINFO_NAME]	@ get machine name
	add	r0, r0, r4
	bl	printascii
	mov	r0, #'\n'
	bl	printch
	add	r5, r5, #SIZEOF_MACHINE_DESC	@ next machine_desc
	cmp	r5, r6
	blo	1b
	adr	r0, str_a3
	bl	printascii
	b	__error
str_a1:	.asciz	"\nError: unrecognized/unsupported machine ID (r1 = 0x"
str_a2:	.asciz	").\n\nAvailable machine support:\n\nID (hex)\tNAME\n"
str_a3:	.asciz	"\nPlease check your kernel config and/or bootloader.\n"
	.align
#endif

	.type	__error, %function
__error:
#ifdef CONFIG_ARCH_RPC
/*
 * Turn the screen red on a error - RiscPC only.
 */
	mov	r0, #0x02000000
	mov	r3, #0x11
	orr	r3, r3, r3, lsl #8
	orr	r3, r3, r3, lsl #16
	str	r3, [r0], #4
	str	r3, [r0], #4
	str	r3, [r0], #4
	str	r3, [r0], #4
#endif
1:	mov	r0, r0
	b	1b


/*
 * Read processor ID register (CP#15, CR0), and look up in the linker-built
 * supported processor list.  Note that we can't use the absolute addresses
 * for the __proc_info lists since we aren't running with the MMU on
 * (and therefore, we are not in the correct address space).  We have to
 * calculate the offset.
 *
 *	r9 = cpuid
 * Returns:
 *	r3, r4, r6 corrupted
 *	r5 = proc_info pointer in physical address space
 *	r9 = cpuid (preserved)
 */
	.type	__lookup_processor_type, %function
__lookup_processor_type:
	adr	r3, 3f
	ldmda	r3, {r5 - r7}
	sub	r3, r3, r7			@ get offset between virt&phys
	add	r5, r5, r3			@ convert virt addresses to
	add	r6, r6, r3			@ physical address space
1:	ldmia	r5, {r3, r4}			@ value, mask
	and	r4, r4, r9			@ mask wanted bits
	teq	r3, r4
	beq	2f
	add	r5, r5, #PROC_INFO_SZ		@ sizeof(proc_info_list)
	cmp	r5, r6
	blo	1b
	mov	r5, #0				@ unknown processor
2:	mov	pc, lr

/*
 * This provides a C-API version of the above function.
 */
ENTRY(lookup_processor_type)
	stmfd	sp!, {r4 - r7, r9, lr}
	mov	r9, r0
	bl	__lookup_processor_type
	mov	r0, r5
	ldmfd	sp!, {r4 - r7, r9, pc}

/*
 * Look in include/asm-arm/procinfo.h and arch/arm/kernel/arch.[ch] for
 * more information about the __proc_info and __arch_info structures.
 */
	.long	__proc_info_begin
	.long	__proc_info_end
3:	.long	.
	.long	__arch_info_begin
	.long	__arch_info_end

/*
 * Lookup machine architecture in the linker-build list of architectures.
 * Note that we can't use the absolute addresses for the __arch_info
 * lists since we aren't running with the MMU on (and therefore, we are
 * not in the correct address space).  We have to calculate the offset.
 *
 *  r1 = machine architecture number
 * Returns:
 *  r3, r4, r6 corrupted
 *  r5 = mach_info pointer in physical address space
 */
	.type	__lookup_machine_type, %function
__lookup_machine_type:
	adr	r3, 3b
	ldmia	r3, {r4, r5, r6}
	sub	r3, r3, r4			@ get offset between virt&phys
	add	r5, r5, r3			@ convert virt addresses to
	add	r6, r6, r3			@ physical address space
1:	ldr	r3, [r5, #MACHINFO_TYPE]	@ get machine type
	teq	r3, r1				@ matches loader number?
	beq	2f				@ found
	add	r5, r5, #SIZEOF_MACHINE_DESC	@ next machine_desc
	cmp	r5, r6
	blo	1b
	mov	r5, #0				@ unknown machine
2:	mov	pc, lr

/*
 * This provides a C-API version of the above function.
 */
ENTRY(lookup_machine_type)
	stmfd	sp!, {r4 - r6, lr}
	mov	r1, r0
	bl	__lookup_machine_type
	mov	r0, r5
	ldmfd	sp!, {r4 - r6, pc}

/* Determine validity of the r2 atags pointer.  The heuristic requires
 * that the pointer be aligned, in the first 16k of physical RAM and
 * that the ATAG_CORE marker is first and present.  Future revisions
 * of this function may be more lenient with the physical address and
 * may also be able to move the ATAGS block if necessary.
 *
 * r8  = machinfo
 *
 * Returns:
 *  r2 either valid atags pointer, or zero
 *  r5, r6 corrupted
 */

	.type	__vet_atags, %function
__vet_atags:
	tst	r2, #0x3			@ aligned?
	bne	1f

	ldr	r5, [r2, #0]			@ is first tag ATAG_CORE?
	subs	r5, r5, #ATAG_CORE_SIZE
	bne	1f
	ldr	r5, [r2, #4]
	ldr	r6, =ATAG_CORE
	cmp	r5, r6
	bne	1f

	mov	pc, lr				@ atag pointer is ok

1:	mov	r2, #0
	mov	pc, lr
Commit	Line	Data
75d90832 HC	1	/*
	2	* linux/arch/arm/kernel/head-common.S
	3	*
	4	* Copyright (C) 1994-2002 Russell King
	5	* Copyright (c) 2003 ARM Limited
	6	* All Rights Reserved
	7	*
	8	* This program is free software; you can redistribute it and/or modify
	9	* it under the terms of the GNU General Public License version 2 as
	10	* published by the Free Software Foundation.
	11	*
	12	*/
	13
9c4c9f38 GU	14	#define ATAG_CORE 0x54410001
	15	#define ATAG_CORE_SIZE ((24 + 34) >> 2)
	16
75d90832 HC	17	.type __switch_data, %object
	18	__switch_data:
	19	.long __mmap_switched
	20	.long __data_loc @ r4
	21	.long __data_start @ r5
	22	.long __bss_start @ r6
	23	.long _end @ r7
	24	.long processor_id @ r4
	25	.long __machine_arch_type @ r5
9d20fdd5 BG	26	.long __atags_pointer @ r6
9d20fdd5 BG	27	.long cr_alignment @ r7
75d90832 HC	28	.long init_thread_union + THREAD_START_SP @ sp
	29
	30	/*
	31	* The following fragment of code is executed with the MMU on in MMU mode,
	32	* and uses absolute addresses; this is not position independent.
	33	*
	34	* r0 = cp#15 control register
	35	* r1 = machine ID
9d20fdd5	36	* r2 = atags pointer
75d90832 HC	37	* r9 = processor ID
	38	*/
	39	.type __mmap_switched, %function
	40	__mmap_switched:
	41	adr r3, __switch_data + 4
	42
	43	ldmia r3!, {r4, r5, r6, r7}
	44	cmp r4, r5 @ Copy data segment if needed
	45	1: cmpne r5, r6
	46	ldrne fp, [r4], #4
	47	strne fp, [r5], #4
	48	bne 1b
	49
	50	mov fp, #0 @ Clear BSS (and zero fp)
	51	1: cmp r6, r7
	52	strcc fp, [r6],#4
	53	bcc 1b
	54
9d20fdd5	55	ldmia r3, {r4, r5, r6, r7, sp}
75d90832 HC	56	str r9, [r4] @ Save processor ID
75d90832 HC	57	str r1, [r5] @ Save machine type
9d20fdd5	58	str r2, [r6] @ Save atags pointer
75d90832	59	bic r4, r0, #CR_A @ Clear 'A' bit
9d20fdd5	60	stmia r7, {r0, r4} @ Save control register values
75d90832 HC	61	b start_kernel
	62
	63	/*
	64	* Exception handling. Something went wrong and we can't proceed. We
	65	* ought to tell the user, but since we don't have any guarantee that
	66	* we're even running on the right architecture, we do virtually nothing.
	67	*
	68	* If CONFIG_DEBUG_LL is set we try to print out something about the error
	69	* and hope for the best (useful if bootloader fails to pass a proper
	70	* machine ID for example).
	71	*/
	72
	73	.type __error_p, %function
	74	__error_p:
	75	#ifdef CONFIG_DEBUG_LL
	76	adr r0, str_p1
	77	bl printascii
	78	b __error
	79	str_p1: .asciz "\nError: unrecognized/unsupported processor variant.\n"
	80	.align
	81	#endif
	82
	83	.type __error_a, %function
	84	__error_a:
	85	#ifdef CONFIG_DEBUG_LL
	86	mov r4, r1 @ preserve machine ID
	87	adr r0, str_a1
	88	bl printascii
	89	mov r0, r4
	90	bl printhex8
	91	adr r0, str_a2
	92	bl printascii
	93	adr r3, 3f
	94	ldmia r3, {r4, r5, r6} @ get machine desc list
	95	sub r4, r3, r4 @ get offset between virt&phys
	96	add r5, r5, r4 @ convert virt addresses to
	97	add r6, r6, r4 @ physical address space
	98	1: ldr r0, [r5, #MACHINFO_TYPE] @ get machine type
	99	bl printhex8
	100	mov r0, #'\t'
	101	bl printch
	102	ldr r0, [r5, #MACHINFO_NAME] @ get machine name
	103	add r0, r0, r4
	104	bl printascii
	105	mov r0, #'\n'
	106	bl printch
	107	add r5, r5, #SIZEOF_MACHINE_DESC @ next machine_desc
	108	cmp r5, r6
	109	blo 1b
	110	adr r0, str_a3
	111	bl printascii
	112	b __error
	113	str_a1: .asciz "\nError: unrecognized/unsupported machine ID (r1 = 0x"
	114	str_a2: .asciz ").\n\nAvailable machine support:\n\nID (hex)\tNAME\n"
	115	str_a3: .asciz "\nPlease check your kernel config and/or bootloader.\n"
	116	.align
	117	#endif
	118
	119	.type __error, %function
	120	__error:
	121	#ifdef CONFIG_ARCH_RPC
	122	/*
	123	* Turn the screen red on a error - RiscPC only.
	124	*/
125	mov r0, #0x02000000
126	mov r3, #0x11
127	orr r3, r3, r3, lsl #8
128	orr r3, r3, r3, lsl #16
129	str r3, [r0], #4
130	str r3, [r0], #4
131	str r3, [r0], #4
132	str r3, [r0], #4
133	#endif
134	1: mov r0, r0
135	b 1b
136
137
138	/*
139	* Read processor ID register (CP#15, CR0), and look up in the linker-built
140	* supported processor list. Note that we can't use the absolute addresses
141	* for the __proc_info lists since we aren't running with the MMU on
142	* (and therefore, we are not in the correct address space). We have to
143	* calculate the offset.
144	*
145	* r9 = cpuid
146	* Returns:
147	* r3, r4, r6 corrupted
148	* r5 = proc_info pointer in physical address space
149	* r9 = cpuid (preserved)
150	*/
151	.type __lookup_processor_type, %function
152	__lookup_processor_type:
153	adr r3, 3f
154	ldmda r3, {r5 - r7}
155	sub r3, r3, r7 @ get offset between virt&phys
156	add r5, r5, r3 @ convert virt addresses to
157	add r6, r6, r3 @ physical address space
158	1: ldmia r5, {r3, r4} @ value, mask
159	and r4, r4, r9 @ mask wanted bits
160	teq r3, r4
161	beq 2f
162	add r5, r5, #PROC_INFO_SZ @ sizeof(proc_info_list)
163	cmp r5, r6
164	blo 1b
165	mov r5, #0 @ unknown processor
166	2: mov pc, lr
167
168	/*
169	* This provides a C-API version of the above function.
170	*/
171	ENTRY(lookup_processor_type)
172	stmfd sp!, {r4 - r7, r9, lr}
173	mov r9, r0
174	bl __lookup_processor_type
175	mov r0, r5
176	ldmfd sp!, {r4 - r7, r9, pc}
177
178	/*
179	* Look in include/asm-arm/procinfo.h and arch/arm/kernel/arch.[ch] for
180	* more information about the __proc_info and __arch_info structures.
181	*/
182	.long __proc_info_begin
183	.long __proc_info_end
184	3: .long .
185	.long __arch_info_begin
186	.long __arch_info_end
187
188	/*
189	* Lookup machine architecture in the linker-build list of architectures.
190	* Note that we can't use the absolute addresses for the __arch_info
191	* lists since we aren't running with the MMU on (and therefore, we are
192	* not in the correct address space). We have to calculate the offset.
193	*
194	* r1 = machine architecture number
195	* Returns:
196	* r3, r4, r6 corrupted
197	* r5 = mach_info pointer in physical address space
198	*/
199	.type __lookup_machine_type, %function
200	__lookup_machine_type:
201	adr r3, 3b
202	ldmia r3, {r4, r5, r6}
203	sub r3, r3, r4 @ get offset between virt&phys
204	add r5, r5, r3 @ convert virt addresses to
205	add r6, r6, r3 @ physical address space
206	1: ldr r3, [r5, #MACHINFO_TYPE] @ get machine type
207	teq r3, r1 @ matches loader number?
208	beq 2f @ found
209	add r5, r5, #SIZEOF_MACHINE_DESC @ next machine_desc
210	cmp r5, r6
211	blo 1b
212	mov r5, #0 @ unknown machine
213	2: mov pc, lr
214
215	/*
216	* This provides a C-API version of the above function.
217	*/
218	ENTRY(lookup_machine_type)
219	stmfd sp!, {r4 - r6, lr}
220	mov r1, r0
221	bl __lookup_machine_type
222	mov r0, r5
223	ldmfd sp!, {r4 - r6, pc}
9d20fdd5 BG	224
	225	/* Determine validity of the r2 atags pointer. The heuristic requires
	226	* that the pointer be aligned, in the first 16k of physical RAM and
	227	* that the ATAG_CORE marker is first and present. Future revisions
	228	* of this function may be more lenient with the physical address and
	229	* may also be able to move the ATAGS block if necessary.
	230	*
	231	* r8 = machinfo
	232	*
	233	* Returns:
	234	* r2 either valid atags pointer, or zero
	235	* r5, r6 corrupted
	236	*/
	237
	238	.type __vet_atags, %function
	239	__vet_atags:
	240	tst r2, #0x3 @ aligned?
	241	bne 1f
	242
	243	ldr r5, [r2, #0] @ is first tag ATAG_CORE?
	244	subs r5, r5, #ATAG_CORE_SIZE
	245	bne 1f
	246	ldr r5, [r2, #4]
	247	ldr r6, =ATAG_CORE
	248	cmp r5, r6
	249	bne 1f
	250
	251	mov pc, lr @ atag pointer is ok
	252
	253	1: mov r2, #0
	254	mov pc, lr