ARM: Add base support for ARMv7-M
This patch adds the base support for the ARMv7-M
architecture. It consists of the corresponding arch/arm/mm/ files and
various #ifdef's around the kernel. Exception handling is implemented by
a subsequent patch.
[ukleinek: squash in some changes originating from commit
b5717ba (Cortex-M3: Add support for the Microcontroller Prototyping System)
from the v2.6.33-arm1 patch stack, port to post 3.6, drop zImage
support, drop reorganisation of pt_regs, assert CONFIG_CPU_V7M doesn't
leak into installed headers and a few cosmetic changes]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Jonathan Austin <jonathan.austin@arm.com>
Tested-by: Jonathan Austin <jonathan.austin@arm.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
diff --git a/arch/arm/mm/proc-v7m.S b/arch/arm/mm/proc-v7m.S
new file mode 100644
index 0000000..000499c
--- /dev/null
+++ b/arch/arm/mm/proc-v7m.S
@@ -0,0 +1,157 @@
+/*
+ * linux/arch/arm/mm/proc-v7m.S
+ *
+ * Copyright (C) 2008 ARM Ltd.
+ * Copyright (C) 2001 Deep Blue Solutions Ltd.
+ *
+ * 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.
+ *
+ * This is the "shell" of the ARMv7-M processor support.
+ */
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+#include <asm/v7m.h>
+#include "proc-macros.S"
+
+ENTRY(cpu_v7m_proc_init)
+ mov pc, lr
+ENDPROC(cpu_v7m_proc_init)
+
+ENTRY(cpu_v7m_proc_fin)
+ mov pc, lr
+ENDPROC(cpu_v7m_proc_fin)
+
+/*
+ * cpu_v7m_reset(loc)
+ *
+ * Perform a soft reset of the system. Put the CPU into the
+ * same state as it would be if it had been reset, and branch
+ * to what would be the reset vector.
+ *
+ * - loc - location to jump to for soft reset
+ */
+ .align 5
+ENTRY(cpu_v7m_reset)
+ mov pc, r0
+ENDPROC(cpu_v7m_reset)
+
+/*
+ * cpu_v7m_do_idle()
+ *
+ * Idle the processor (eg, wait for interrupt).
+ *
+ * IRQs are already disabled.
+ */
+ENTRY(cpu_v7m_do_idle)
+ wfi
+ mov pc, lr
+ENDPROC(cpu_v7m_do_idle)
+
+ENTRY(cpu_v7m_dcache_clean_area)
+ mov pc, lr
+ENDPROC(cpu_v7m_dcache_clean_area)
+
+/*
+ * There is no MMU, so here is nothing to do.
+ */
+ENTRY(cpu_v7m_switch_mm)
+ mov pc, lr
+ENDPROC(cpu_v7m_switch_mm)
+
+.globl cpu_v7m_suspend_size
+.equ cpu_v7m_suspend_size, 0
+
+#ifdef CONFIG_ARM_CPU_SUSPEND
+ENTRY(cpu_v7m_do_suspend)
+ mov pc, lr
+ENDPROC(cpu_v7m_do_suspend)
+
+ENTRY(cpu_v7m_do_resume)
+ mov pc, lr
+ENDPROC(cpu_v7m_do_resume)
+#endif
+
+ .section ".text.init", #alloc, #execinstr
+
+/*
+ * __v7m_setup
+ *
+ * This should be able to cover all ARMv7-M cores.
+ */
+__v7m_setup:
+ @ Configure the vector table base address
+ ldr r0, =BASEADDR_V7M_SCB
+ ldr r12, =vector_table
+ str r12, [r0, V7M_SCB_VTOR]
+
+ @ enable UsageFault, BusFault and MemManage fault.
+ ldr r5, [r0, #V7M_SCB_SHCSR]
+ orr r5, #(V7M_SCB_SHCSR_USGFAULTENA | V7M_SCB_SHCSR_BUSFAULTENA | V7M_SCB_SHCSR_MEMFAULTENA)
+ str r5, [r0, #V7M_SCB_SHCSR]
+
+ @ Lower the priority of the SVC and PendSV exceptions
+ mov r5, #0x80000000
+ str r5, [r0, V7M_SCB_SHPR2] @ set SVC priority
+ mov r5, #0x00800000
+ str r5, [r0, V7M_SCB_SHPR3] @ set PendSV priority
+
+ @ SVC to run the kernel in this mode
+ adr r1, BSYM(1f)
+ ldr r5, [r12, #11 * 4] @ read the SVC vector entry
+ str r1, [r12, #11 * 4] @ write the temporary SVC vector entry
+ mov r6, lr @ save LR
+ mov r7, sp @ save SP
+ ldr sp, =__v7m_setup_stack_top
+ cpsie i
+ svc #0
+1: cpsid i
+ str r5, [r12, #11 * 4] @ restore the original SVC vector entry
+ mov lr, r6 @ restore LR
+ mov sp, r7 @ restore SP
+
+ @ Special-purpose control register
+ mov r1, #1
+ msr control, r1 @ Thread mode has unpriviledged access
+
+ @ Configure the System Control Register to ensure 8-byte stack alignment
+ @ Note the STKALIGN bit is either RW or RAO.
+ ldr r12, [r0, V7M_SCB_CCR] @ system control register
+ orr r12, #V7M_SCB_CCR_STKALIGN
+ str r12, [r0, V7M_SCB_CCR]
+ mov pc, lr
+ENDPROC(__v7m_setup)
+
+ define_processor_functions v7m, dabort=nommu_early_abort, pabort=legacy_pabort, nommu=1
+
+ .section ".rodata"
+ string cpu_arch_name, "armv7m"
+ string cpu_elf_name "v7m"
+ string cpu_v7m_name "ARMv7-M"
+
+ .section ".proc.info.init", #alloc, #execinstr
+
+ /*
+ * Match any ARMv7-M processor core.
+ */
+ .type __v7m_proc_info, #object
+__v7m_proc_info:
+ .long 0x000f0000 @ Required ID value
+ .long 0x000f0000 @ Mask for ID
+ .long 0 @ proc_info_list.__cpu_mm_mmu_flags
+ .long 0 @ proc_info_list.__cpu_io_mmu_flags
+ b __v7m_setup @ proc_info_list.__cpu_flush
+ .long cpu_arch_name
+ .long cpu_elf_name
+ .long HWCAP_HALF|HWCAP_THUMB|HWCAP_FAST_MULT|HWCAP_IDIVT
+ .long cpu_v7m_name
+ .long v7m_processor_functions @ proc_info_list.proc
+ .long 0 @ proc_info_list.tlb
+ .long 0 @ proc_info_list.user
+ .long nop_cache_fns @ proc_info_list.cache
+ .size __v7m_proc_info, . - __v7m_proc_info
+
+__v7m_setup_stack:
+ .space 4 * 8 @ 8 registers
+__v7m_setup_stack_top:
