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/********************************************************************
* dm320/dm320_restart.S
*
* Copyright (C) 2007 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
*
* 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 Gregory Nutt 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 "up_internal.h"
#include "up_arch.h"
/********************************************************************
* Definitions
********************************************************************/
/********************************************************************
* Assembly Macros
********************************************************************/
/* Since the page table is closely related to the NuttX base
* address, we can convert the page table base address to the
* base address of the section containing both.
*/
.macro mksection, section, pgtable
bic \section, \pgtable, #0x000ff000
.endm
/**************************************************************************
* Name: up_restart
**************************************************************************/
.text
.globl up_restart
.type up_restart, %function
up_restart:
/* Make sure that we are in SVC mode with all IRQs disabled */
mov r0, #(SVC_MODE | PSR_I_BIT | PSR_F_BIT)
msr cpsr_c, r0
/* Create identity mapping for first MB section to support
* this re-start logic executing out of the physical address
* space.
*/
mksection r0, r4 /* r0=phys. base section */
ldr r1, .LCmmuflags /* FLGS=MMU_MEMFLAGS */
add r3, r1, r0 /* r3=flags + base */
str r3, [r4, r0, lsr #18] /* identity mapping */
/* Jump into the physical address space */
ldr pc, .LCphysrestart
nop
nop
/* We are now executing at our physical address, with the
* MMU disabled.
*/
up_phyrestart:
mov r0, #0
mcr p15, 0, r0, c7, c7 /* Invalidate I,D caches */
mcr p15, 0, r0, c7, c10, 4 /* Drain write buffer */
mcr p15, 0, r0, c8, c7 /* Invalidate I,D TLBs */
/* Clear bits in control register (see start.h): Disable,
* MMU, Data cache, alignment traps, write buffer, Instruction
* cache, exceptions at 0xffff0000, round robin)
*/
mrc p15, 0, r0, c1, c0 /* Get control register */
bic r0, r0, #(CR_M|CR_C|CR_A|CR_W)
bic r0, r0, #(CR_S|CR_I|CR_V|CR_RR)
mcr p15, 0, r0, c1, c0, 0 /* Write control reg */
/* We know that the the bootloader entry point is at the
* beginning of flash.
*/
#if 1
ldr pc, .LCbtldrentry /* Restart bootloader */
#else
b __start /* Restart Nuttx */
#endif
.type .LCphysrestart, %object
.LCphysrestart:
.long (up_phyrestart - CONFIG_DRAM_VSTART - CONFIG_DRAM_START)
.LCbtldrentry:
.long DM320_EXT_MEM_PADDR
/**************************************************************************
* PC_Relative Data
**************************************************************************/
.type .LCmmuflags, %object
.LCmmuflags:
.long MMU_MEMFLAGS
.size up_restart, .-up_restart
.end
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