arch/cris/boot/rescue/kimagerescue.S

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * Rescue code to be prepended on a kimage and copied to the
   4  * rescue serial port.
   5  * This is called from the rescue code, it will copy received data to
   6  * 4004000 and after a timeout jump to it.
   7  */
   8
   9 #define ASSEMBLER_MACROS_ONLY
  10 #include <arch/sv_addr_ag.h>
  11
  12 #define CODE_START 0x40004000
  13 #define CODE_LENGTH 784
  14 #define TIMEOUT_VALUE 1000
  15
  16
  17 #ifdef CONFIG_ETRAX_RESCUE_SER0
  18 #define SERXOFF R_SERIAL0_XOFF
  19 #define SERBAUD R_SERIAL0_BAUD
  20 #define SERRECC R_SERIAL0_REC_CTRL
  21 #define SERRDAT R_SERIAL0_REC_DATA
  22 #define SERSTAT R_SERIAL0_STATUS
  23 #endif
  24 #ifdef CONFIG_ETRAX_RESCUE_SER1
  25 #define SERXOFF R_SERIAL1_XOFF
  26 #define SERBAUD R_SERIAL1_BAUD
  27 #define SERRECC R_SERIAL1_REC_CTRL
  28 #define SERRDAT R_SERIAL1_REC_DATA
  29 #define SERSTAT R_SERIAL1_STATUS
  30 #endif
  31 #ifdef CONFIG_ETRAX_RESCUE_SER2
  32 #define SERXOFF R_SERIAL2_XOFF
  33 #define SERBAUD R_SERIAL2_BAUD
  34 #define SERRECC R_SERIAL2_REC_CTRL
  35 #define SERRDAT R_SERIAL2_REC_DATA
  36 #define SERSTAT R_SERIAL2_STATUS
  37 #endif
  38 #ifdef CONFIG_ETRAX_RESCUE_SER3
  39 #define SERXOFF R_SERIAL3_XOFF
  40 #define SERBAUD R_SERIAL3_BAUD
  41 #define SERRECC R_SERIAL3_REC_CTRL
  42 #define SERRDAT R_SERIAL3_REC_DATA
  43 #define SERSTAT R_SERIAL3_STATUS
  44 #endif
  45
  46         .text
  47         ;; This is the entry point of the rescue code
  48         ;; 0x80000000 if loaded in flash (as it should be)
  49         ;; since etrax actually starts at address 2 when booting from flash, we
  50         ;; put a nop (2 bytes) here first so we dont accidentally skip the di
  51
  52         nop
  53         di
  54         ;; setup port PA and PB default initial directions and data
  55         ;; (so we can flash LEDs, and so that DTR and others are set)
  56
  57         move.b  CONFIG_ETRAX_DEF_R_PORT_PA_DIR, $r0
  58         move.b  $r0, [R_PORT_PA_DIR]
  59         move.b  CONFIG_ETRAX_DEF_R_PORT_PA_DATA, $r0
  60         move.b  $r0, [R_PORT_PA_DATA]
  61
  62         move.b  CONFIG_ETRAX_DEF_R_PORT_PB_DIR, $r0
  63         move.b  $r0, [R_PORT_PB_DIR]
  64         move.b  CONFIG_ETRAX_DEF_R_PORT_PB_DATA, $r0
  65         move.b  $r0, [R_PORT_PB_DATA]
  66
  67         ;; We need to setup the bus registers before we start using the DRAM
  68 #include "../../lib/dram_init.S"
  69
  70         ;; Setup the stack to a suitably high address.
  71         ;; We assume 8 MB is the minimum DRAM in an eLinux
  72         ;; product and put the sp at the top for now.
  73
  74         move.d  0x40800000, $sp
  75
  76         ;; setup the serial port at 115200 baud
  77
  78         moveq   0, $r0
  79         move.d  $r0, [SERXOFF]
  80
  81         move.b  0x99, $r0
  82         move.b  $r0, [SERBAUD]          ; 115.2kbaud for both transmit
  83                                         ; and receive
  84
  85         move.b  0x40, $r0               ; rec enable
  86         move.b  $r0, [SERRECC]
  87
  88
  89         moveq   0, $r1                  ; "timer" to clock out a LED red flash
  90         move.d  CODE_START, $r3         ; destination counter
  91         move.d  CODE_LENGTH, $r4        ; length
  92         move.d  TIMEOUT_VALUE, $r5      ; "timeout" until jump
  93
  94 wait_ser:
  95         addq    1, $r1
  96         subq    1, $r5                  ; decrease timeout
  97         beq     jump_start              ; timed out
  98         nop
  99 #ifndef CONFIG_ETRAX_NO_LEDS
 100 #ifdef CONFIG_ETRAX_PA_LEDS
 101         move.b  CONFIG_ETRAX_DEF_R_PORT_PA_DATA, $r2
 102 #endif
 103 #ifdef CONFIG_ETRAX_PB_LEDS
 104         move.b  CONFIG_ETRAX_DEF_R_PORT_PB_DATA, $r2
 105 #endif
 106         move.d  (1 << CONFIG_ETRAX_LED1R) | (1 << CONFIG_ETRAX_LED2R), $r0
 107         btstq   16, $r1
 108         bpl     1f
 109         nop
 110         or.d    $r0, $r2                ; set bit
 111         ba      2f
 112         nop
 113 1:      not     $r0                     ; clear bit
 114         and.d   $r0, $r2
 115 2:
 116 #ifdef CONFIG_ETRAX_PA_LEDS
 117         move.b  $r2, [R_PORT_PA_DATA]
 118 #endif
 119 #ifdef CONFIG_ETRAX_PB_LEDS
 120         move.b  $r2, [R_PORT_PB_DATA]
 121 #endif
 122 #endif
 123
 124         ;; check if we got something on the serial port
 125
 126         move.b  [SERSTAT], $r0
 127         btstq   0, $r0                  ; data_avail
 128         bpl     wait_ser
 129         nop
 130
 131         ;; got something - copy the byte and loop
 132
 133         move.b  [SERRDAT], $r0
 134         move.b  $r0, [$r3+]
 135         move.d  TIMEOUT_VALUE, $r5      ; reset "timeout"
 136         subq    1, $r4                  ; decrease length
 137         bne     wait_ser
 138         nop
 139 jump_start:
 140         ;; jump into downloaded code
 141
 142         jump    CODE_START