vectors.s

基于ecos的redboot

// #========================================================================
// #
// #    vectors.S
// #
// #    ARM exception vectors
// #
// #========================================================================
// ####COPYRIGHTBEGIN####
//                                                                          
// -------------------------------------------                              
// The contents of this file are subject to the Red Hat eCos Public License 
// Version 1.1 (the "License"); you may not use this file except in         
// compliance with the License.  You may obtain a copy of the License at    
// http://www.redhat.com/                                                   
//                                                                          
// Software distributed under the License is distributed on an "AS IS"      
// basis, WITHOUT WARRANTY OF ANY KIND, either express or implied.  See the 
// License for the specific language governing rights and limitations under 
// the License.                                                             
//                                                                          
// The Original Code is eCos - Embedded Configurable Operating System,      
// released September 30, 1998.                                             
//                                                                          
// The Initial Developer of the Original Code is Red Hat.                   
// Portions created by Red Hat are                                          
// Copyright (C) 1998, 1999, 2000, 2001 Red Hat, Inc.
// All Rights Reserved.                                                     
// -------------------------------------------                              
//                                                                          
// ####COPYRIGHTEND####
// #========================================================================
// ######DESCRIPTIONBEGIN####
// #
// # Author(s):     nickg, gthomas
// # Contributors:  nickg, gthomas, lagarwal
// # Date:          1999-02-20
// # Purpose:       ARM exception vectors
// # Description:   This file defines the code placed into the exception
// #                vectors. It also contains the first level default VSRs
// #                that save and restore state for both exceptions and
// #                interrupts.
// #
// #####DESCRIPTIONEND####
// #
// #========================================================================

#include <pkgconf/hal.h>
#include <pkgconf/hal_arm.h>
#ifdef CYGPKG_KERNEL  // no CDL yet
#include <pkgconf/kernel.h>
#else
# undef CYGFUN_HAL_COMMON_KERNEL_SUPPORT
# undef CYGIMP_HAL_COMMON_INTERRUPTS_USE_INTERRUPT_STACK
#endif
#include <cyg/hal/hal_platform_setup.h>

#define CYGSEM_HAL_ROM_RESET_USES_JUMP

#ifdef CYGDBG_HAL_DEBUG_GDB_INCLUDE_STUBS
// The CDL should enforce this
#undef  CYGHWR_HAL_ARM_DUMP_EXCEPTIONS
#endif

#include "arm.inc"

#ifdef __thumb__
// Switch to thumb mode
#define THUMB_MODE(_r_, _l_)                     \
        ldr     _r_,=_l_ ## f+1                 ;\
        bx      _r_                             ;\
        .pool                                   ;\
        .code   16                              ;\
        .thumb_func                             ;\
 _l_:

// Switch to ARM mode
#define ARM_MODE(_r_, _l_)                       \
        ldr     _r_,=_l_ ## f                   ;\
        bx      _r_                             ;\
        .pool                                   ;\
        .code   32                              ;\
 _l_:

// Function definition, start executing body in ARM mode
#define FUNC_START_ARM(_name_, _r_)              \
        .code   16                              ;\
        .thumb_func                             ;\
        .globl _name_                           ;\
_name_:                                         ;\
        ldr     _r_,=_name_ ## _ARM             ;\
        bx      _r_                             ;\
        .code   32                              ;\
_name_ ## _ARM:

#else

// Switch to thumb mode
#define THUMB_MODE(_r_, _l_)

// Switch to ARM mode
#define ARM_MODE(_r_, _l_)

// Function definition, start executing body in ARM mode
#define FUNC_START_ARM(_name_, _r_) \
        .globl _name_; \
_name_: 

#endif

        

#define PTR(name)               \
.##name: .word  name

// CYGHWR_HAL_ROM_VADDR is used when compiling for a different location
// from the base of ROM.  hal_platform_setup.h might define it.  For
// example, if flash is from 0x50000000 upwards (as on SA11x0), and we are
// to execute at 0x50040000, then we want the reset vector to point to
// 0x0004pqrs - the unmapped ROM address of the code - rather than
// 0x0000pqrs, which is the offset into our flash block.
// 
// But usually it's not defined, so the behaviour is the obvious.

#ifndef UNMAPPED        
#ifdef CYGHWR_HAL_ARM_HAS_MMU
# ifndef CYGHWR_HAL_ROM_VADDR
#  define CYGHWR_HAL_ROM_VADDR __exception_handlers
# endif
# define UNMAPPED(x) ((x)-CYGHWR_HAL_ROM_VADDR)
#else
# define UNMAPPED(x) (x)
#endif
#endif        
                                
#define UNMAPPED_PTR(name)              \
.##name: .word  UNMAPPED(name)

        .file   "vectors.S"


// CYGHWR_LED_MACRO can be defined in hal_platform_setup.h. It's free to
// use r0+r1. Argument is in "\x" - cannot use macro arguments since the
// macro may contain #-chars and use of arguments cause these to be 
// interpreted as CPP stringify operators.
// See example in PID hal_platform_setup.h.
#ifndef CYGHWR_LED_MACRO
#define CYGHWR_LED_MACRO
#endif
        
.macro LED x
    CYGHWR_LED_MACRO
.endm


//==========================================================================
// Hardware exception vectors.
//   This entire section will be copied to location 0x0000 at startup time.
//
        .code   32
        .section ".vectors","ax"

// This macro allows platforms to add their own code at the very start of
// the image.  This may be required in some circumstances where eCos ROM 
// based code does not run immediately upon reset and/or when some sort of
// special header is required at the start of the image.        
#ifdef PLATFORM_PREAMBLE
        PLATFORM_PREAMBLE
#endif
                        
        .global __exception_handlers
__exception_handlers:
#ifdef CYGSEM_HAL_ROM_RESET_USES_JUMP
// Assumption:  ROM code has these vectors at the hardware reset address.
// A simple jump removes any address-space dependencies [i.e. safer]
	    b       reset_vector                    // 0x00
#else        
        ldr     pc,.reset_vector                // 0x00
#endif
        ldr     pc,.undefined_instruction       // 0x04
        ldr     pc,.software_interrupt          // 0x08 start && software int
        ldr     pc,.abort_prefetch              // 0x0C
        ldr     pc,.abort_data                  // 0x10
        .word   0                               // unused
        ldr     pc,.IRQ                         // 0x18
        ldr     pc,.FIQ                         // 0x1C

// The layout of these pointers should match the vector table above since
// they are copied in pairs.
        .global vectors
vectors:
UNMAPPED_PTR(reset_vector)                      // 0x20
PTR(undefined_instruction)                      // 0x24
PTR(software_interrupt)                         // 0x28
PTR(abort_prefetch)                             // 0x2C
PTR(abort_data)                                 // 0x30
        .word   0                               // 0x34
PTR(IRQ)                                        // 0x38
PTR(FIQ)                                        // 0x3c
#ifdef CYGSEM_HAL_ARM_PID_ANGEL_BOOT         
PTR(start) // This is copied to 0x28 for bootup // 0x40
#endif        
           // location 0x40 is used for storing DRAM size if known
           // for some platforms.
        
//
// "Vectors" - fixed location data items
//    This section contains any data which might be shared between
// an eCos application and any other environment, e.g. the debug
// ROM.                        
//
        .section ".fixed_vectors"
        // Interrupt/exception VSR pointers
        .globl  hal_vsr_table
hal_vsr_table:
        .rept   8               
        .long   0
        .endr

        .globl  hal_dram_size
hal_dram_size:  
        .long   0
	// what, if anything, hal_dram_type means is up to the platform
        .globl  hal_dram_type
hal_dram_type:  
        .long   0

        .balign 16
#ifdef CYGSEM_HAL_VIRTUAL_VECTOR_SUPPORT
	// Vectors used to communicate between eCos and ROM environments
        .globl  hal_virtual_vector_table
hal_virtual_vector_table:
        .rept   CYGNUM_CALL_IF_TABLE_SIZE
        .long   0
        .endr
#endif
        
#ifdef CYGHWR_HAL_ARM_ICE_THREAD_SUPPORT
        .balign 16      // Should be at 0x50
ice_thread_vector:
        .long   0       // Must be 'MICE'             
        .long   0       // Pointer to thread support vector
        .long   0       // eCos executing flag
        .long   0       // Must be 'GDB '
#endif // CYGHWR_HAL_ARM_ICE_THREAD_SUPPORT
        .balign 32
        
// Other vectors - this may include "fixed" locations
#ifdef PLATFORM_VECTORS
        PLATFORM_VECTORS
#endif
                        
        .text   
// Startup code which will get the machine into supervisor mode
        .global reset_vector
        .type   reset_vector,function
reset_vector:
        PLATFORM_SETUP1         // Early stage platform initialization
                                // which can set DRAM size at 0x40
                                // see <cyg/hal/hal_platform_setup.h>

        // Come here to reset board
warm_reset:      

#if defined(CYG_HAL_STARTUP_RAM) && \
    !defined(CYGDBG_HAL_DEBUG_GDB_INCLUDE_STUBS)
        mrs     r7,cpsr                 // move back to IRQ mode
        and     r7,r7,#CPSR_MODE_BITS
        cmp     r7,#CPSR_SUPERVISOR_MODE
        beq     start
#endif

        // We cannot access any LED registers until after PLATFORM_SETUP1
        LED 7

        mov     r0,#0           // move vectors
		// if no flash then you are running out of SDRAM. So no need of moving vector table
		cmp r10, #0
		beq ice_support

        ldr     r1,=(SLOW_PORT_BASE + __exception_handlers)
#ifndef CYGDBG_HAL_DEBUG_GDB_INCLUDE_STUBS
        // Wait with this if stubs are included (see further down).
        ldr     r2,[r1,#0x04]   // undefined instruction
        str     r2,[r0,#0x04]
        ldr     r2,[r1,#0x24]   
        str     r2,[r0,#0x24]
#endif
        ldr     r2,[r1,#0x08]   // software interrupt
        str     r2,[r0,#0x08]

ice_support:
#ifdef CYGHWR_HAL_ARM_ICE_THREAD_SUPPORT        
        ldr     r2,=ice_thread_vector
        sub     r2,r2,r1        // compute fixed (low memory) address
        ldr     r3,=0x4D494345  // 'MICE'
        str     r3,[r2],#4
        ldr     r3,=hal_arm_ice_thread_handler
        str     r3,[r2],#4
        mov     r3,#1
        str     r3,[r2],#4
        ldr     r3,=0x47444220  // 'GDB '
        str     r3,[r2],#4
#endif // CYGHWR_HAL_ARM_ICE_THREAD_SUPPORT

#if defined(CYGSEM_HAL_ARM_PID_ANGEL_BOOT)
// Ugly hack to get into supervisor mode
        ldr     r2,[r1,#0x40]
        str     r2,[r0,#0x28]

        LED 6
                
        swi                     // switch to supervisor mode
#endif        

// =========================================================================
// Real startup code. We jump here from the reset vector to set up the world.
        .globl  start
start:  

        LED 5

#if defined(CYG_HAL_STARTUP_RAM) && \
    !defined(CYGDBG_HAL_DEBUG_GDB_INCLUDE_STUBS)
// If we get restarted, hang here to avoid corrupting memory
        ldr     r0,.init_flag
        ldr     r1,[r0]
1:      cmp     r1,#0
        bne     1b
        ldr     r1,=init_done
        str     r1,[r0]
#endif

        // Reset software interrupt pointer
        mov     r0,#0           // move vectors

		// if no flash then you are running out of SDRAM. So no need of moving vector table
		cmp r10, #0
		beq skip_dram_copy

        ldr     r1,=(SLOW_PORT_BASE + __exception_handlers)
#if defined(CYG_HAL_STARTUP_RAM) && \
    !defined(CYGDBG_HAL_DEBUG_GDB_INCLUDE_STUBS)
        cmp     r7,#CPSR_SUPERVISOR_MODE
        beq     10f
#endif
#if !defined(CYG_HAL_STARTUP_ROMRAM)
        ldr     r2,[r1,#0x28]   // software interrupt
        str     r2,[r0,#0x28]
10:
        ldr     r2,[r1,#0x18]   // IRQ
        str     r2,[r0,#0x18]
        ldr     r2,[r1,#0x38]
        str     r2,[r0,#0x38]
        ldr     r2,[r1,#0x1C]   // FIQ
        str     r2,[r0,#0x1C]
        ldr     r2,[r1,#0x3C]
        str     r2,[r0,#0x3C]
        ldr     r2,[r1,#0x0C]   // abort (prefetch)
        str     r2,[r0,#0x0C]
        ldr     r2,[r1,#0x2C]   
        str     r2,[r0,#0x2C]
        ldr     r2,[r1,#0x10]   // abort (data)
        str     r2,[r0,#0x10]
        ldr     r2,[r1,#0x30]
        str     r2,[r0,#0x30]
#endif

        LED 4

#if defined(CYG_HAL_STARTUP_ROM) || defined(CYG_HAL_STARTUP_ROMRAM)
        // Set up reset vector
        mov     r0,#0
		ldr     r1,=(SLOW_PORT_BASE + __exception_handlers)