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walnux/arch/arm/src/armv7-a/arm_cpuhead.S

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/****************************************************************************
* arch/arm/src/armv7-a/arm_cpuhead.S
*
* Copyright (C) 2016 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <arch/board/board.h>
#include "arm.h"
#include "cp15.h"
#include "sctlr.h"
#include "mmu.h"
#include "smp.h"
#include "chip.h"
#include "up_internal.h"
#ifdef CONFIG_SMP
.file "arm_cpuhead.S"
/**********************************************************************************
* Configuration
**********************************************************************************/
/* Hard-coded options */
#undef CPU_ALIGNMENT_TRAP
#undef CPU_CACHE_ROUND_ROBIN
#undef CPU_DCACHE_DISABLE
#undef CPU_ICACHE_DISABLE
#undef CPU_AFE_ENABLE
/* Check for the identity mapping: For this configuration, this would be
* the case where the virtual beginning of RAM is the same as the physical
* beginning of RAM.
*/
#if !defined(CONFIG_RAM_START) || !defined(CONFIG_RAM_VSTART)
# error "CONFIG_RAM_START or CONFIG_RAM_VSTART is not defined"
#endif
#if CONFIG_RAM_START == CONFIG_RAM_VSTART
# define CONFIG_IDENTITY_TEXTMAP 1
#endif
/****************************************************************************
* .text
****************************************************************************/
.text
/****************************************************************************
* Name: __cpu[n]_start
*
* Description:
* Boot functions for each CPU (other than CPU0). These functions set up
* the ARM operating mode, the initial stack, and configure co-processor
* registers. At the end of the boot, arm_cpu_boot() is called.
*
* These functions are provided by the common ARMv7-A logic.
*
* Input Parameters:
* None
*
* Returned Value:
* Do not return.
*
****************************************************************************/
#if CONFIG_SMP_NCPUS > 1
.global __cpu1_start
.type __cpu1_start, #function
__cpu1_start:
/* Set up the stack pointer and the CPU index */
ldr sp, .Lcpu1_stackpointer
mov r5, #1
/* Then branch to the common startup logic (PC-relative) */
b .Lcpu_start
.Lcpu1_stackpointer:
.long .Lcpu1_stacktop
.size __cpu1_start, .-__cpu1_start
#if CONFIG_SMP_NCPUS > 2
.global __cpu2_start
.type __cpu2_start, #function
__cpu2_start:
/* Set up the stack pointer and the CPU index */
ldr sp, .Lcpu2_stackpointer
mov r5, #2
/* Then branch to the common startup logic (PC-relative) */
b .Lcpu_start
.Lcpu2_stackpointer:
.long .Lcpu2_stacktop
.size __cpu2_start, .-__cpu2_start
#if CONFIG_SMP_NCPUS > 3
.global __cpu3_start
.type __cpu3_start, #function
__cpu3_start:
/* Set up the stack pointer and the CPU index */
ldr sp, .Lcpu3_stackpointer
mov r5, #3
/* Then branch to the common startup logic (PC-relative) */
b .Lcpu_start
.Lcpu3_stackpointer:
.long .Lcpu3_stacktop
.size __cpu3_start, .-__cpu3_start
#if CONFIG_SMP_NCPUS > 4
# error This logic needs to extended for CONFIG_SMP_NCPUS > 4
#endif /* CONFIG_SMP_NCPUS > 4 */
#endif /* CONFIG_SMP_NCPUS > 3 */
#endif /* CONFIG_SMP_NCPUS > 2 */
#endif /* CONFIG_SMP_NCPUS > 1 */
/****************************************************************************
* Name: .Lcpu_start
*
* Description:
* Common CPUn startup logic (n > 0)
*
* On input:
* SP = Set to top of CPU IDLE stack (virtual)
* R5 = CPU number
*
****************************************************************************/
.type .Lcpu_start, #function
.Lcpu_start:
/* Make sure that we are in SVC mode with IRQs and FIQs disabled */
mov r0, #(PSR_MODE_SVC | PSR_I_BIT | PSR_F_BIT)
msr cpsr_c, r0
/* The MMU and caches should be disabled */
mrc CP15_SCTLR(r0)
bic r0, r0, #(SCTLR_M | SCTLR_C)
bic r0, r0, #(SCTLR_I)
mcr CP15_SCTLR(r0)
/* Invalidate caches and TLBs.
*
* NOTE: "The ARMv7 Virtual Memory System Architecture (VMSA) does not
* support a CP15 operation to invalidate the entire data cache. ...
* In normal usage the only time the entire data cache has to be
* invalidated is on reset."
*
* The instruction cache is virtually indexed and physically tagged but
* the data cache is physically indexed and physically tagged. So it
* should not be an issue if the system comes up with a dirty Dcache;
* the ICache, however, must be invalidated.
*/
mov r0, #0
mcr CP15_TLBIALL(r0,c7) /* Invalidate the entire unified TLB */
mcr CP15_TLBIALL(r0,c6)
mcr CP15_TLBIALL(r0,c5)
mcr CP15_BPIALL(r0) /* Invalidate entire branch prediction array */
mcr CP15_ICIALLU(r0) /* Invalidate I-cache */
/* Load the page table address.
*
* NOTES:
* - Here we assume that the page table address is aligned to at least
* least a 16KB boundary (bits 0-13 are zero). No masking is provided
* to protect against an unaligned page table address.
* - The ARMv7-A has two page table address registers, TTBR0 and 1.
* Only TTBR0 is used in this implementation but both are initialized.
*/
ldr r1, .LCppgtable /* r1=phys. page table */
orr r1, r1, #(TTBR0_RGN_WBWA | TTBR0_IRGN0) /* Select cache properties */
mcr CP15_TTBR0(r1)
mcr CP15_TTBR1(r1)
/* Set the TTB control register (TTBCR) to indicate that we are using
* TTBR0. r0 still holds the value of zero.
*
* N : 0=Selects TTBR0 and 16KB page table size indexed by VA[31:20]
* PD0 : 0=Perform translation table walks using TTBR0
* PD1 : 0=Perform translation table walks using TTBR1 (but it is disabled)
* EAE : 0=Use 32-bit translation system
*/
mcr CP15_TTBCR(r0)
/* Enable the MMU and caches
* lr = Resume at .Lcpu_vstart with the MMU enabled
*/
ldr lr, .LCcpu_vstart /* Abs. virtual address */
/* Configure the domain access register (see mmu.h). Only domain 0 is
* supported and it uses the permissions in the TLB.
*/
mov r0, #DACR_CLIENT(0)
mcr CP15_DACR(r0) /* Set domain access register */
/* Configure the system control register (see sctrl.h) */
mrc CP15_SCTLR(r0) /* Get control register */
/* Clear bits to reset values. This is only necessary in situations like, for
* example, we get here via a bootloader and the control register is in some
* unknown state.
*
* SCTLR_M Bit 0: Enable the MMU
* SCTLR_A Bit 1: Strict alignment disabled (reset value)
* SCTLR_C Bit 2: DCache disabled (reset value)
*
* SCTLR_SW Bit 10: SWP/SWPB not enabled (reset value)
* SCTLR_I Bit 12: ICache disabled (reset value)
* SCTLR_V Bit 13: Assume low vectors (reset value)
* SCTLR_RR Bit 14: The Cortex-A5 processor only supports a fixed random
* replacement strategy.
* SCTLR_HA Bit 17: Not supported by A5
*
* SCTLR_EE Bit 25: 0=Little endian (reset value).
* SCTLR_TRE Bit 28: No memory region remapping (reset value)
* SCTLR_AFE Bit 29: Full, legacy access permissions behavior (reset value).
* SCTLR_TE Bit 30: All exceptions handled in ARM state (reset value).
*/
bic r0, r0, #(SCTLR_A | SCTLR_C)
bic r0, r0, #(SCTLR_SW | SCTLR_I | SCTLR_V | SCTLR_RR | SCTLR_HA)
bic r0, r0, #(SCTLR_EE | SCTLR_TRE | SCTLR_AFE | SCTLR_TE)
/* Set bits to enable the MMU
*
* SCTLR_M Bit 0: Enable the MMU
* SCTLR_Z Bit 11: Program flow prediction control always enabled on A5
*/
orr r0, r0, #(SCTLR_M)
#ifndef CONFIG_ARCH_CORTEXA5
orr r0, r0, #(SCTLR_Z)
#endif
#ifndef CONFIG_ARCH_LOWVECTORS
/* Position vectors to 0xffff0000 if so configured.
*
* SCTLR_V Bit 13: High vectors
*/
orr r0, r0, #(SCTLR_V)
#endif
#if defined(CPU_CACHE_ROUND_ROBIN) && !defined(CONFIG_ARCH_CORTEXA5)
/* Round Robin cache replacement
*
* SCTLR_RR Bit 14: The Cortex-A5 processor only supports a fixed random
* replacement strategy.
*/
orr r0, r0, #(SCTLR_RR)
#endif
/* In SMP configurations, the data cache will not be enabled until later
* after SMP cache coherency has been setup.
*/
#if 0 /* !defined(CPU_DCACHE_DISABLE) && !defined(CONFIG_SMP) */
/* Dcache enable
*
* SCTLR_C Bit 2: DCache enable
*/
orr r0, r0, #(SCTLR_C)
#endif
#ifndef CPU_ICACHE_DISABLE
/* Icache enable
*
* SCTLR_I Bit 12: ICache enable
*/
orr r0, r0, #(SCTLR_I)
#endif
#ifdef CPU_ALIGNMENT_TRAP
/* Alignment abort enable
*
* SCTLR_A Bit 1: Strict alignment enabled
*/
orr r0, r0, #(SCTLR_A)
#endif
#ifdef CONFIG_ENDIAN_BIG
/* Big endian mode
*
* SCTLR_EE Bit 25: 1=Big endian.
*/
orr r0, r0, #(SCTLR_EE)
#endif
#ifdef CPU_AFE_ENABLE
/* AP[0:2] Permissions model
*
* SCTLR_AFE Bit 29: Full, legacy access permissions behavior (reset value).
*
* When AFE=1, the page table AP[0] is used as an access flag and AP[2:1]
* control. When AFE=0, AP[2:0] control access permissions.
*/
orr r0, r0, #(SCTLR_AFE)
#endif
/* Then write the configured control register */
mcr CP15_SCTLR(r0) /* Write control reg */
.rept 12 /* Cortex A8 wants lots of NOPs here */
nop
.endr
/* And "jump" to .Lcpu_vstart in the newly mapped virtual address space */
mov pc, lr
/****************************************************************************
* PC_Relative Data
****************************************************************************/
/* The physical base address of the page table */
.type .LCppgtable, %object
.LCppgtable:
.long PGTABLE_BASE_PADDR /* Physical start of page table */
.size .LCppgtable, . -.LCppgtable
/* The virtual start address of the second phase boot logic */
.type .LCcpu_vstart, %object
.LCcpu_vstart:
.long .Lcpu_vstart
.size .LCcpu_vstart, . -.LCcpu_vstart
.size .Lcpu_start, .-.Lcpu_start
/****************************************************************************
* Name: .Lcpu_vstart
*
* Description:
* Continue initialization after the MMU has been enabled.
*
* The following is executed after the MMU has been enabled. This uses
* absolute addresses; this is not position independent.
*
* On input:
* SP = Set to top of CPU IDLE stack (virtual)
* R5 = CPU number
*
****************************************************************************/
.align 8
.globl arm_cpu_boot
.type .Lcpu_vstart, %function
.Lcpu_vstart:
#ifdef CONFIG_STACK_COLORATION
/* Write a known value to the IDLE thread stack to support stack
* monitoring logic
*/
adr r3, .Lstkinit
ldmia r3, {r0, r1, r2} /* R0 = start of IDLE stack; R1 = Size of stack; R2 = coloration */
1: /* Top of the loop */
sub r1, r1, #1 /* R1 = Number of words remaining */
cmp r1, #0 /* Check (nwords == 0) */
str r2, [r0], #4 /* Save stack color word, increment stack address */
bne 1b /* Bottom of the loop */
#endif
/* Branch to continue C level CPU initialization */
mov fp, #0 /* Clear framepointer */
mov lr, #0 /* LR = return address (none) */
mov r0, r5 /* Input parameter = CPU index */
b arm_cpu_boot /* Branch to C level CPU initialization */
.size .Lcpu_vstart, .-.Lcpu_vstart
/***************************************************************************
* Text-section constants
***************************************************************************/
/* Text-section constants: */
#ifdef CONFIG_STACK_COLORATION
.type .Lstkinit, %object
.Lstkinit:
.long SMP_STACK_WORDS
.long STACK_COLOR /* Stack coloration word */
.size .Lstkinit, . -.Lstkinit
#endif
/***************************************************************************
* .noinit section data
***************************************************************************/
.section .noinit, "aw"
#if CONFIG_SMP_NCPUS > 1
.align 8
.globl g_cpu1_idlestack
.type g_cpu1_idlestack, object
g_cpu1_idlestack:
.space SMP_STACK_SIZE
.Lcpu1_stacktop:
.size g_cpu1_idlestack, .Lcpu1_stacktop-g_cpu1_idlestack
#if CONFIG_SMP_NCPUS > 2
.align 8
.globl g_cpu2_idlestack
.type g_cpu2_idlestack, object
g_cpu2_idlestack:
.space SMP_STACK_SIZE
.Lcpu2_stacktop:
.size g_cpu2_idlestack, .Lcpu2_stacktop-g_cpu2_idlestack
#if CONFIG_SMP_NCPUS > 3
.align 8
.globl g_cpu3_idlestack
.type g_cpu3_idlestack, object
g_cpu3_idlestack:
.space SMP_STACK_SIZE
.Lcpu3_stacktop:
.size g_cpu3_idlestack, .Lcpu3_stacktop-g_cpu3_idlestack
#if CONFIG_SMP_NCPUS > 4
# error This logic needs to extended for CONFIG_SMP_NCPUS > 4
#endif /* CONFIG_SMP_NCPUS > 4 */
#endif /* CONFIG_SMP_NCPUS > 3 */
#endif /* CONFIG_SMP_NCPUS > 2 */
#endif /* CONFIG_SMP_NCPUS > 1 */
#endif
.end
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