165 lines
4.9 KiB
C
165 lines
4.9 KiB
C
/****************************************************************************
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* arch/arm/src/samd2l2/sam_start.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <stdint.h>
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#include <assert.h>
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#include <debug.h>
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#include <nuttx/init.h>
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#include "arm_internal.h"
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#include "sam_config.h"
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#include "sam_lowputc.h"
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#include "sam_clockconfig.h"
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#include "sam_userspace.h"
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#include "sam_start.h"
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/* Memory Map:
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*
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* 0x0000:0000 - Beginning of FLASH. Address of exception vectors.
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* 0x0003:ffff - End of flash (assuming 256KB of FLASH)
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* 0x2000:0000 - Start of SRAM and start of .data (_sdata)
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* - End of .data (_edata) abd start of .bss (_sbss)
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* - End of .bss (_ebss) and bottom of idle stack
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* - _ebss + CONFIG_IDLETHREAD_STACKSIZE = end of idle stack,
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* start of heap
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* 0x2000:ffff - End of SRAM and end of heap (assuming 64KB of SRAM)
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*/
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#define IDLE_STACK ((uint32_t)_ebss + CONFIG_IDLETHREAD_STACKSIZE)
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/****************************************************************************
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* Public Data
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****************************************************************************/
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const uintptr_t g_idle_topstack = IDLE_STACK;
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: showprogress
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*
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* Description:
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* Print a character on the UART to show boot status.
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*
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****************************************************************************/
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#if defined(CONFIG_DEBUG_FEATURES) && defined(HAVE_SERIAL_CONSOLE)
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# define showprogress(c) sam_lowputc((uint32_t)c)
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#else
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# define showprogress(c)
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#endif
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: __start
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*
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* Description:
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* This is the reset entry point.
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*
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****************************************************************************/
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void __start(void)
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{
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const uint32_t *src;
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uint32_t *dest;
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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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for (dest = (uint32_t *)_sbss; dest < (uint32_t *)_ebss; )
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{
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*dest++ = 0;
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}
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/* Move the initialized data section from his temporary holding spot in
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* FLASH into the correct place in SRAM. The correct place in SRAM is
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* give by _sdata and _edata. The temporary location is in FLASH at the
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* end of all of the other read-only data (.text, .rodata) at _eronly.
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*/
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for (src = (const uint32_t *)_eronly,
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dest = (uint32_t *)_sdata; dest < (uint32_t *)_edata;
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)
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{
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*dest++ = *src++;
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}
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/* Configure basic clocking */
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sam_clockconfig();
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/* Configure the uart early so that we can get debug output as soon as
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* possible
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*/
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sam_lowsetup();
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showprogress('A');
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/* Perform early serial initialization */
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#ifdef USE_EARLYSERIALINIT
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arm_earlyserialinit();
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#endif
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showprogress('B');
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/* For the case of the separate user-/kernel-space build, perform whatever
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* platform specific initialization of the user memory is required.
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* Normally this just means initializing the user space .data and .bss
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* segments.
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*/
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#ifdef CONFIG_BUILD_PROTECTED
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sam_userspace();
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showprogress('C');
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#endif
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/* Initialize onboard resources */
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sam_boardinitialize();
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showprogress('D');
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/* Then start NuttX */
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showprogress('\r');
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showprogress('\n');
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nx_start();
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/* Shouldn't get here */
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for (; ; );
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}
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