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/****************************************************************************
* arch/hc/src/m9s12/m9s12_start.S
* arch/hc/src/chip/m9s12_start.S
*
* Copyright (C) 2009, 2011 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 "m9s12_internal.h"
#include "m9s12_mmc.h"
#include "m9s12_crg.h"
#include "m9s12_flash.h"
/****************************************************************************
* Private Definitions
****************************************************************************/
#ifdef CONFIG_HCS12_NONBANKED
# define CALL jsr
# define RETURN rts
#else
# define CALL call
# define RETURN rtc
#endif
#define INITRG_REG (MMC_INITRG_REG(HCS12_REG_BASE))
#define INITRM_MAP (MMC_INITRM_RAM(HCS12_SRAM_BASE)|MMC_INITRM_RAMHAL)
#define INITEE_EE (MMC_INITEE_EE(HCS12_EEPROM_BASE)|MMC_INITEE_EEON)
/****************************************************************************
* Global Symbols
****************************************************************************/
.file "m9s12_start.S"
.globl __start
.globl os_start
.globl up_lowsetup
.globl hcs12_boardinitialize
/****************************************************************************
* Macros
****************************************************************************/
/* Print a character on the UART to show boot status. This macro will
* modify r0, r1, r2 and r14
*/
.macro showprogress, code
#ifdef CONFIG_DEBUG
ldab \code
#ifdef CONFIG_HCS12_SERIALMON
jsr #PutChar
#else
CALL up_lowputc
#endif
#endif
.endm
/* Memory map initialization.
*
* The MC9S12NE64 has 64K bytes of FLASH EEPROM and 8K bytes of RAM.
*/
.macro MMCINIT
/* Registers are always positioned at address 0x0000 */
movb #INITRG_REG, HCS12_MMC_INITRG /* Set the register map position to 0x0000*/
nop
/* Position SRAM so that is ends at address 0x3fff. This is required
* because the Freescale serial monitor initializes its stack to the
* end+1 of SRAM which it expects to be at address 0x4000
*/
movb #INITRM_MAP, HCS12_MMC_INITRM /* Set RAM position to 0x2000-0x3fff */
movb #INITEE_EE, HCS12_MMC_INITEE /* Set EEPROM position to 0x0800 */
/* In the non-banked mode, PPAGE is set to 0x3d to create a (non-contiguous),
* fixed, 48Kb .text address space.
*/
#ifdef CONFIG_HCS12_NONBANKED
movb #0x3d, HCS12_MMC_PPAGE
#endif
movb #MMC_MISC_ROMON, HCS12_MMC_MISC /* MISC: EXSTR1=0 EXSTR0=0 ROMHM=0 ROMON=1 */
.endm
/* System clock initialization. If the serial monitor is used, then clocking will have
* already been configured at 24 MHz
*/
.macro PLLINIT
#ifndef CONFIG_HCS12_SERIALMON
/* Select the clock source from crystal */
clr HCS12_CRG_CLKSEL
/* Set the multipler and divider and enable the PLL */
bclr *HCS12_CRG_PLLCTL #CRG_PLLCTL_PLLON
ldab #HCS12_SYNR_VALUE
stab HCS12_CRG_SYNR
ldab #HCS12_REFDV_VALUE
stab HCS12_CRG_REFDV
bset *HCS12_CRG_PLLCTL #CRG_PLLCTL_PLLON
/* Wait for the PLL to lock on */
.Lpll_lock:
brclr *HCS12_CRG_CRGFLG #CRG_CRGFLG_LOCK .Lpll_lock
/* Then select the PLL clock source */
bset *HCS12_CRG_CLKSEL #CRG_CLKSEL_PLLSEL
#endif
.endm
/****************************************************************************
* .text
****************************************************************************/
.section nonbanked, "x"
/****************************************************************************
* Name: __start
*
* Description:
* Power-up reset entry point
*
****************************************************************************/
__start:
/* Hardware setup */
MMCINIT /* Initialize the MMC */
PLLINIT /* Initialize the PLL */
/* Setup the stack pointer */
lds .Lstackbase
/* Perform early, low-level initialization */
#ifndef CONFIG_HCS12_SERIALMON
CALL up_lowsetup
#endif
showprogress 'A'
/* Clear BSS */
ldx .Lsbss /* Start of .BSS */
ldd .Lebss /* End+1 of .BSS */
.Lclearbss:
pshd
cpx 2,sp+ /* Check if all BSS has been cleared */
beq .Lbsscleared /* If so, exit the loop */
clr 0,x /* Clear this byte */
inx /* Address the next byte */
bra .Lclearbss /* And loop until all cleared */
.Lbsscleared:
showprogress 'B'
/* Initialize the data section */
ldx .Lsdata /* Start of .DATA (destination) */
movw .Ledata, 0, sp /* End of .DATA (destination) */
ldy .Leronly /* Start of .DATA (source) */
.Linitdata:
cpx 0, sp /* Check if all .DATA has been initialized */
beq .Ldatainitialized /* If so, exit the loop */
ldab 0, y /* Fetch the next byte from the source */
iny /* Increment the source address */
stab 0, x /* Store the byte to the destination */
inx /* Increment the destination address */
bra .Linitdata /* And loop until all of .DATA is initialized */
.Ldatainitialized:
showprogress 'C'
/* Perform early board-level initialization */
CALL hcs12_boardinitialize
showprogress 'D'
/* Now, start the OS */
showprogress '\n'
CALL os_start
bra __start
/* Variables:
* _sbss is the start of the BSS region (see ld.script)
* _ebss is the end of the BSS regsion (see ld.script)
* The idle task stack starts at the end of BSS and is
* of size CONFIG_IDLETHREAD_STACKSIZE. The heap continues
* from there until the end of memory. See g_idle_topstack
* below.
*/
.Lsbss:
.hword _sbss
.Lebss:
.hword _ebss
.Lstackbase:
.hword _ebss+CONFIG_IDLETHREAD_STACKSIZE-4
.Leronly:
.hword _eronly /* Where .data defaults are stored in FLASH */
.Lsdata:
.hword _sdata /* Where .data needs to reside in SDRAM */
.Ledata:
.hword _edata
.size __start, .-__start
/************************************************************************************
* .rodata
************************************************************************************/
.section .rodata, "a"
/* Variables: _sbss is the start of the BSS region (see ld.script) _ebss is the end
* of the BSS regsion (see ld.script). The idle task stack starts at the end of BSS
* and is of size CONFIG_IDLETHREAD_STACKSIZE. The IDLE thread is the thread that
* the system boots on and, eventually, becomes the idle, do nothing task that runs
* only when there is nothing else to run. The heap continues from there until the
* end of memory. See g_idle_topstack below.
*/
.globl g_idle_topstack
.type g_idle_topstack, object
g_idle_topstack:
.hword _ebss+CONFIG_IDLETHREAD_STACKSIZE
.size g_idle_topstack, .-g_idle_topstack
.end
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