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/* Cstartup header for the application to be started by at91dfu
* (C) 2006 by Harald Welte <hwelte@hmw-consulting.de>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
//#define DEBUG_LL
.equ AIC_FVR, (260)
.equ AIC_EOICR, (304)
.equ AT91C_BASE_AIC, (0xFFFFF000)
.equ ARM_MODE_FIQ, 0x11
.equ ARM_MODE_IRQ, 0x12
.equ ARM_MODE_SVC, 0x13
.equ I_BIT, 0x80
.equ F_BIT, 0x40
#define AT91C_BASE_PIOA 0xFFFFF400
#define AT91C_BASE_TC0 0xFFFA0000
#define AT91C_TC_SWTRG (1 << 2)
#define PIOA_SODR 0x30
#define PIOA_CODR 0x34
#define PIOA_PDSR 0x3c
#define PIOA_ISR 0x4c
#define PIOA_IDR 0x44
#define PIO_DATA (1 << 27)
#define TC_CCR 0x00
#define PIO_LED1 (1 << 25) /* this only works on OpenPICC, not Olimex */
#ifdef DEBUG_LL
/* Debugging macros for switching on/off LED1 (green) */
#define PIOA_PER 0xFFFFF400
#define PIOA_OER 0xFFFFF410
.macro led1on
ldr r2, =AT91C_BASE_PIOA
mov r1, #PIO_LED1
str r1, [r2, #PIOA_CODR]
.endm
.macro led1off
ldr r2, =AT91C_BASE_PIOA
mov r1, #PIO_LED1
str r1, [r2, #PIOA_SODR]
.endm
.macro ledinit
ldr r2, =PIOA_PER
mov r1, #PIO_LED1
str r1, [r2]
ldr r2, =PIOA_OER
str r1, [r2]
led1off
.endm
#else
.macro ledinit
.endm
.macro led1on
.endm
.macro led1off
.endm
#endif
.global _startup
.func _startup
_startup:
/* Relocate .data section (copy from Flash to RAM) */
ldr r1, =_etext
ldr r2, =_data
ldr r3, =_edata
loop_r: cmp r2, r3
ldrlo r0, [r1], #4
strlo r0, [r2], #4
blo loop_r
/* Clear .bss section (Zero init) */
mov r0, #0
ldr r1, =__bss_start__
ldr r2, =__bss_end__
loop_z: cmp r1, r2
strlo r0, [r1], #4
blo loop_z
/* initialize FIQ mode registers */
msr CPSR_c, #ARM_MODE_FIQ | I_BIT | F_BIT
ldr r10, =AT91C_BASE_PIOA
ldr r12, =AT91C_BASE_TC0
mov r9, #AT91C_TC_SWTRG
msr CPSR_c, #ARM_MODE_SVC
led1on
/* prepare C function call to main */
mov r0, #0 /* argc = 0 */
ldr lr, =exit
ldr r10, =main
bx r10
.size _startup, . - _startup
.endfunc
/* "exit" dummy to avoid sbrk write read etc. needed by the newlib default "exit" */
.global exit
.func exit
exit:
b .
.size exit, . - exit
.endfunc
.text
.arm
.section .fastrun, "ax"
.global fiq_handler
.func fiq_handler
fiq_handler:
/* code that uses pre-initialized FIQ reg */
/* r8 AT91C_BASE_AIC (dfu init)
r9 AT91C_TC_SWTRG
r10 AT91C_BASE_PIOA
r11 tmp
r12 AT91C_BASE_TC0
r13 stack
r14 lr
*/
#if 0
mov r11, #PIO_LED1
str r11, [r10, #PIOA_CODR] /* enable LED */
str r11, [r10, #PIOA_SODR] /* disable LED */
#endif
ldr r8, [r10, #PIOA_ISR]
tst r8, #PIO_DATA /* check for PIO_DATA change */
ldrne r11, [r10, #PIOA_PDSR]
tstne r11, #PIO_DATA /* check for PIO_DATA == 1 */
strne r9, [r12, #TC_CCR] /* software trigger */
movne r11, #PIO_DATA
strne r11, [r10, #PIOA_IDR] /* disable further PIO_DATA FIQ */
/*- Mark the End of Interrupt on the AIC */
ldr r11, =AT91C_BASE_AIC
str r11, [r11, #AIC_EOICR]
/* push r0, r1-r3, r12, r14 onto FIQ stack */
stmfd sp!, { r0-r3, r12, lr}
mov r0, r8
/* enable interrupts while handling demux */
/* msr CPSR_c, #F_BIT | ARM_MODE_SVC */
/* Call C function, give PIOA_ISR as argument */
ldr r11, =__pio_irq_demux
mov r14, pc
bx r11
/* msr CPSR_c, #I_BIT | F_BIT | ARM_MODE_FIQ */
ldmia sp!, { r0-r3, r12, lr }
#if 0
/*- Save and r0 in FIQ_Register */
mov r9, r0
ldr r0, [r11, #AIC_FVR]
str r8, [r11, #AIC_FVR]
/* msr CPSR_c, #I_BIT | F_BIT | ARM_MODE_SVC */
/*- Save scratch/used registers and LR in User Stack */
stmfd sp!, { r1-r3, r12, lr}
led1on
/*- Branch to the routine pointed by the AIC_FVR */
mov r14, pc
bx r0
/*- Restore scratch/used registers and LR from User Stack */
ldmia sp!, { r1-r3, r12, lr}
/*- Leave Interrupts disabled and switch back in FIQ mode */
/* msr CPSR_c, #I_BIT | F_BIT | ARM_MODE_FIQ */
/*- Mark the End of Interrupt on the AIC */
ldr r0, =AT91C_BASE_AIC
str r0, [r0, #AIC_EOICR]
/*- Restore the R0 ARM_MODE_SVC register */
mov r0,r9
ldr r10, =PIOA_SODR
mov r11, #(1 << LED1)
str r11, [r10]
#endif
/*- Restore the Program Counter using the LR_fiq directly in the PC */
subs pc, lr, #4
.size fiq_handler, . - fiq_handler
.endfunc
.end
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