kimagerescue.S
3.42 KB
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/*
* Rescue code to be prepended on a kimage and copied to the
* rescue serial port.
* This is called from the rescue code, it will copy received data to
* 4004000 and after a timeout jump to it.
*/
#define ASSEMBLER_MACROS_ONLY
#include <arch/sv_addr_ag.h>
#define CODE_START 0x40004000
#define CODE_LENGTH 784
#define TIMEOUT_VALUE 1000
#ifdef CONFIG_ETRAX_RESCUE_SER0
#define SERXOFF R_SERIAL0_XOFF
#define SERBAUD R_SERIAL0_BAUD
#define SERRECC R_SERIAL0_REC_CTRL
#define SERRDAT R_SERIAL0_REC_DATA
#define SERSTAT R_SERIAL0_STATUS
#endif
#ifdef CONFIG_ETRAX_RESCUE_SER1
#define SERXOFF R_SERIAL1_XOFF
#define SERBAUD R_SERIAL1_BAUD
#define SERRECC R_SERIAL1_REC_CTRL
#define SERRDAT R_SERIAL1_REC_DATA
#define SERSTAT R_SERIAL1_STATUS
#endif
#ifdef CONFIG_ETRAX_RESCUE_SER2
#define SERXOFF R_SERIAL2_XOFF
#define SERBAUD R_SERIAL2_BAUD
#define SERRECC R_SERIAL2_REC_CTRL
#define SERRDAT R_SERIAL2_REC_DATA
#define SERSTAT R_SERIAL2_STATUS
#endif
#ifdef CONFIG_ETRAX_RESCUE_SER3
#define SERXOFF R_SERIAL3_XOFF
#define SERBAUD R_SERIAL3_BAUD
#define SERRECC R_SERIAL3_REC_CTRL
#define SERRDAT R_SERIAL3_REC_DATA
#define SERSTAT R_SERIAL3_STATUS
#endif
.text
;; This is the entry point of the rescue code
;; 0x80000000 if loaded in flash (as it should be)
;; since etrax actually starts at address 2 when booting from flash, we
;; put a nop (2 bytes) here first so we dont accidentally skip the di
nop
di
;; setup port PA and PB default initial directions and data
;; (so we can flash LEDs, and so that DTR and others are set)
move.b CONFIG_ETRAX_DEF_R_PORT_PA_DIR, $r0
move.b $r0, [R_PORT_PA_DIR]
move.b CONFIG_ETRAX_DEF_R_PORT_PA_DATA, $r0
move.b $r0, [R_PORT_PA_DATA]
move.b CONFIG_ETRAX_DEF_R_PORT_PB_DIR, $r0
move.b $r0, [R_PORT_PB_DIR]
move.b CONFIG_ETRAX_DEF_R_PORT_PB_DATA, $r0
move.b $r0, [R_PORT_PB_DATA]
;; We need to setup the bus registers before we start using the DRAM
#include "../../lib/dram_init.S"
;; Setup the stack to a suitably high address.
;; We assume 8 MB is the minimum DRAM in an eLinux
;; product and put the sp at the top for now.
move.d 0x40800000, $sp
;; setup the serial port at 115200 baud
moveq 0, $r0
move.d $r0, [SERXOFF]
move.b 0x99, $r0
move.b $r0, [SERBAUD] ; 115.2kbaud for both transmit
; and receive
move.b 0x40, $r0 ; rec enable
move.b $r0, [SERRECC]
moveq 0, $r1 ; "timer" to clock out a LED red flash
move.d CODE_START, $r3 ; destination counter
move.d CODE_LENGTH, $r4 ; length
move.d TIMEOUT_VALUE, $r5 ; "timeout" until jump
wait_ser:
addq 1, $r1
subq 1, $r5 ; decrease timeout
beq jump_start ; timed out
nop
#ifndef CONFIG_ETRAX_NO_LEDS
#ifdef CONFIG_ETRAX_PA_LEDS
move.b CONFIG_ETRAX_DEF_R_PORT_PA_DATA, $r2
#endif
#ifdef CONFIG_ETRAX_PB_LEDS
move.b CONFIG_ETRAX_DEF_R_PORT_PB_DATA, $r2
#endif
move.d (1 << CONFIG_ETRAX_LED1R) | (1 << CONFIG_ETRAX_LED2R), $r0
btstq 16, $r1
bpl 1f
nop
or.d $r0, $r2 ; set bit
ba 2f
nop
1: not $r0 ; clear bit
and.d $r0, $r2
2:
#ifdef CONFIG_ETRAX_PA_LEDS
move.b $r2, [R_PORT_PA_DATA]
#endif
#ifdef CONFIG_ETRAX_PB_LEDS
move.b $r2, [R_PORT_PB_DATA]
#endif
#endif
;; check if we got something on the serial port
move.b [SERSTAT], $r0
btstq 0, $r0 ; data_avail
bpl wait_ser
nop
;; got something - copy the byte and loop
move.b [SERRDAT], $r0
move.b $r0, [$r3+]
move.d TIMEOUT_VALUE, $r5 ; reset "timeout"
subq 1, $r4 ; decrease length
bne wait_ser
nop
jump_start:
;; jump into downloaded code
jump CODE_START