SAM3/4: Leverage some start-up logic from STM32
This commit is contained in:
Gregory Nutt
parent
89fd098a20
commit
3b798f6ef1
@ -1,7 +1,7 @@
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/****************************************************************************
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* arch/arm/src/sam34/sam_start.c
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*
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* Copyright (C) 2009-2010, 2012-2013 Gregory Nutt. All rights reserved.
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* Copyright (C) 2009-2010, 2012-2013, 2015 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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@ -54,17 +54,27 @@
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#include "sam_cmcc.h"
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#include "sam_userspace.h"
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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#ifdef CONFIG_ARCH_FPU
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# include "nvic.h"
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#endif
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/****************************************************************************
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* Private Data
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* Private Function prototypes
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****************************************************************************/
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/****************************************************************************
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* Public Data
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****************************************************************************/
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#ifdef CONFIG_ARCH_FPU
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static inline void sam_fpuconfig(void);
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#endif
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#ifdef CONFIG_STACK_COLORATION
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static void go_os_start(void *pv, unsigned int nbytes)
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__attribute__ ((naked,no_instrument_function,noreturn));
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#endif
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#ifdef CONFIG_ARMV7M_STACKCHECK
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/* We need to get r10 set before we can allow instrumentation calls */
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void __start(void) __attribute__ ((no_instrument_function));
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#endif
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/****************************************************************************
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* Private Functions
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@ -84,6 +94,136 @@
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# define showprogress(c)
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#endif
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/****************************************************************************
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* Name: sam_fpuconfig
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*
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* Description:
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* Configure the FPU. Relative bit settings:
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*
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* CPACR: Enables access to CP10 and CP11
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* CONTROL.FPCA: Determines whether the FP extension is active in the
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* current context:
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* FPCCR.ASPEN: Enables automatic FP state preservation, then the
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* processor sets this bit to 1 on successful completion of any FP
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* instruction.
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* FPCCR.LSPEN: Enables lazy context save of FP state. When this is
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* done, the processor reserves space on the stack for the FP state,
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* but does not save that state information to the stack.
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*
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* Software must not change the value of the ASPEN bit or LSPEN bit while either:
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* - the CPACR permits access to CP10 and CP11, that give access to the FP
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* extension, or
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* - the CONTROL.FPCA bit is set to 1
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*
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****************************************************************************/
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#ifdef CONFIG_ARCH_FPU
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#ifdef CONFIG_ARMV7M_CMNVECTOR
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static inline void sam_fpuconfig(void)
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{
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uint32_t regval;
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/* Set CONTROL.FPCA so that we always get the extended context frame
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* with the volatile FP registers stacked above the basic context.
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*/
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regval = getcontrol();
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regval |= (1 << 2);
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setcontrol(regval);
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/* Ensure that FPCCR.LSPEN is disabled, so that we don't have to contend
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* with the lazy FP context save behaviour. Clear FPCCR.ASPEN since we
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* are going to turn on CONTROL.FPCA for all contexts.
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*/
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regval = getreg32(NVIC_FPCCR);
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regval &= ~((1 << 31) | (1 << 30));
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putreg32(regval, NVIC_FPCCR);
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/* Enable full access to CP10 and CP11 */
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regval = getreg32(NVIC_CPACR);
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regval |= ((3 << (2*10)) | (3 << (2*11)));
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putreg32(regval, NVIC_CPACR);
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}
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#else
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static inline void sam_fpuconfig(void)
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{
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uint32_t regval;
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/* Clear CONTROL.FPCA so that we do not get the extended context frame
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* with the volatile FP registers stacked in the saved context.
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*/
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regval = getcontrol();
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regval &= ~(1 << 2);
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setcontrol(regval);
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/* Ensure that FPCCR.LSPEN is disabled, so that we don't have to contend
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* with the lazy FP context save behaviour. Clear FPCCR.ASPEN since we
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* are going to keep CONTROL.FPCA off for all contexts.
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*/
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regval = getreg32(NVIC_FPCCR);
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regval &= ~((1 << 31) | (1 << 30));
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putreg32(regval, NVIC_FPCCR);
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/* Enable full access to CP10 and CP11 */
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regval = getreg32(NVIC_CPACR);
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regval |= ((3 << (2*10)) | (3 << (2*11)));
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putreg32(regval, NVIC_CPACR);
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}
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#endif
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#else
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# define sam_fpuconfig()
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#endif
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/****************************************************************************
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* Name: go_os_start
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*
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* Description:
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* Set the IDLE stack to the
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*
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****************************************************************************/
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#ifdef CONFIG_STACK_COLORATION
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static void go_os_start(void *pv, unsigned int nbytes)
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{
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/* Set the IDLE stack to the stack coloration value then jump to
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* os_start(). We take extreme care here because were currently
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* executing on this stack.
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*
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* We want to avoid sneak stack access generated by the compiler.
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*/
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__asm__ __volatile__
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(
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"\tmov r1, r1, lsr #2\n" /* R1 = nwords = nbytes >> 2 */
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"\tbeq 2f\n" /* (should not happen) */
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"\tbic r0, r0, #3\n" /* R0 = Aligned stackptr */
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"\tmovw r2, #0xbeef\n" /* R2 = STACK_COLOR = 0xdeadbeef */
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"\tmovt r2, #0xdead\n"
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"1:\n" /* Top of the loop */
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"\tsub r1, r1, #1\n" /* R1 nwords-- */
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"\tcmp r1, #0\n" /* Check (nwords == 0) */
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"\tstr r2, [r0], #4\n" /* Save stack color word, increment stackptr */
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"\tbne 1b\n" /* Bottom of the loop */
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"2:\n"
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"\tmov r14, #0\n" /* LR = return address (none) */
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"\tb os_start\n" /* Branch to os_start */
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);
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}
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#endif
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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@ -101,6 +241,12 @@ void __start(void)
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const uint32_t *src;
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uint32_t *dest;
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#ifdef CONFIG_ARMV7M_STACKCHECK
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/* Set the stack limit before we attempt to call any functions */
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__asm__ volatile ("sub r10, sp, %0" : : "r" (CONFIG_IDLETHREAD_STACKSIZE - 64) : );
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#endif
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/* Clear .bss. We'll do this inline (vs. calling memset) just to be
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* certain that there are no issues with the state of global variables.
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*/
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@ -135,9 +281,10 @@ void __start(void)
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}
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#endif
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/* Configure the uart so that we can get debug output as soon as possible */
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/* Configure the UART so that we can get debug output as soon as possible */
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sam_clockconfig();
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sam_fpuconfig();
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sam_lowsetup();
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showprogress('A');
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@ -179,9 +326,19 @@ void __start(void)
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showprogress('\r');
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showprogress('\n');
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#ifdef CONFIG_STACK_COLORATION
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/* Set the IDLE stack to the coloration value and jump into os_start() */
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go_os_start((FAR void *)&_ebss, CONFIG_IDLETHREAD_STACKSIZE);
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#else
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/* Call os_start() */
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os_start();
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/* Shouldn't get here */
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for (;;);
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#endif
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}
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