[ARM] nommu: start-up code
This patch adds nommu version start-up code head-nommu.S.
The common part of the start-up codes is moved to head-common.S.
Signed-off-by: Hyok S. Choi <hyok.choi@samsung.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/kernel/head-common.S b/arch/arm/kernel/head-common.S
new file mode 100644
index 0000000..a52da0d
--- /dev/null
+++ b/arch/arm/kernel/head-common.S
@@ -0,0 +1,217 @@
+/*
+ * 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.
+ *
+ */
+
+ .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 cr_alignment @ r6
+ .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
+ * 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, sp}
+ str r9, [r4] @ Save processor ID
+ str r1, [r5] @ Save machine type
+ bic r4, r0, #CR_A @ Clear 'A' bit
+ stmia r6, {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}