1 | /* |
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2 | * Check interrupt while in trap handler. |
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3 | * Cache is enabled so we have one instruction/cycle |
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4 | */ |
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5 | #include <registers.h> |
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6 | #include <misc.h> |
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7 | #include <vcache.h> |
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8 | #include <xicu.h> |
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9 | |
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10 | #define DOLOAD_ADDR 0x80000000 |
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11 | |
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12 | .text |
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13 | .globl _start |
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14 | _start: |
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15 | .set noreorder |
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16 | la k0, TTY_BASE |
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17 | la k1, EXIT_BASE |
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18 | la sp, 0x00200000 - 16 |
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19 | |
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20 | /* reset cause, make sure IV is off */ |
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21 | mtc0 zero, COP0_CAUSE |
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22 | |
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23 | la a0, pte1 |
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24 | srl a0, a0, 13 |
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25 | mtc2 a0, VC_PTPR |
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26 | nop |
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27 | nop |
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28 | |
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29 | li a0, VC_TLB_EN_ITLB | VC_TLB_EN_DTLB | VC_TLB_EN_ICACHE | VC_TLB_EN_DCACHE |
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30 | mtc2 a0, VC_TLB_EN |
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31 | |
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32 | PRINT(startstr) |
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33 | |
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34 | /* program xicu */ |
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35 | la t0, XICU_BASE |
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36 | /* clear pending interrupt */ |
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37 | lw a0, XICU_PTI_ACK(0)(t0) |
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38 | /* route PTI0 to irq 0 */ |
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39 | li a0, 1 << 0 |
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40 | sw a0, XICU_MSK_PTI_E(0)(t0) |
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41 | /* init s0 */ |
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42 | li s0, MAGIC2 |
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43 | /* |
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44 | * interrupt in INTERRUPT_DELAY cycles. |
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45 | */ |
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46 | li a0, INTERRUPT_DELAY |
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47 | sw a0, XICU_PTI_PER(0)(t0) |
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48 | /* clear pending interrupt */ |
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49 | lw a0, XICU_PTI_ACK(0)(t0) |
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50 | /* reset cop0 status (keep BEV), enable interrupt 0 */ |
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51 | lui a0, 0x0040; |
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52 | addiu a0, 0x0401; |
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53 | mtc0 a0, COP0_STATUS |
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54 | nop |
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55 | nop |
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56 | nop |
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57 | nop |
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58 | nop |
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59 | |
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60 | nop |
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61 | move a1, zero |
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62 | la s0, DOLOAD_ADDR |
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63 | jalr s0 |
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64 | nop |
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65 | j end |
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66 | nop |
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67 | /* we should not end there */ |
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68 | EXIT(1) |
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69 | |
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70 | end: |
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71 | PRINT(endstr) |
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72 | move a0, a1 |
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73 | PRINTX |
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74 | PUTCHAR(' ') |
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75 | la a0, myvar |
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76 | lw a0, 0(a0) |
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77 | PRINTX |
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78 | PUTCHAR('\n') |
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79 | EXIT(0) |
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80 | |
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81 | .globl excep |
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82 | excep: |
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83 | .set noreorder |
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84 | /* don't clobber a0 and ra */ |
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85 | addiu sp, sp, -8 |
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86 | sw a0, 4(sp) |
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87 | sw ra, 8(sp) |
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88 | |
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89 | PRINT(statusstr) |
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90 | mfc0 a0, COP0_STATUS |
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91 | PRINTX |
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92 | |
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93 | PRINT(causestr) |
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94 | mfc0 a0, COP0_CAUSE |
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95 | move s0, a0 |
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96 | PRINTX |
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97 | |
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98 | PRINT(pcstr) |
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99 | mfc0 a0, COP0_EXPC |
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100 | PRINTX |
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101 | |
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102 | PRINT(badvastr) |
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103 | mfc0 a0, COP_0_BADVADDR |
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104 | PRINTX |
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105 | |
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106 | PRINT(xicustr) |
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107 | la t0, XICU_BASE |
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108 | lw a0, XICU_PRIO(0)(t0) |
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109 | PRINTX |
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110 | PUTCHAR('\n') |
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111 | /* map VA DOLOAD_ADDR at PA 0xbfc01000 */ |
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112 | la t0, pte22 + VADDR_TO_PTE2I(DOLOAD_ADDR) * 8 |
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113 | la a0, (0xbfc01000 >> PTE2_SHIFT) |
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114 | sw a0, 4(t0) |
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115 | la a0, (PTE2_V | PTE2_C | PTE2_X) |
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116 | sw a0, 0(t0) |
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117 | mtc2 zero, VC_DCACHE_FLUSH /* flush the whole data cache */ |
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118 | |
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119 | andi a0, s0, 0xff00 |
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120 | beq a0, zero, notintr |
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121 | nop |
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122 | |
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123 | /* disable timer0 */ |
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124 | la t0, XICU_BASE |
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125 | sw zero, XICU_PTI_PER(0)(t0) |
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126 | notintr: |
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127 | la a1, myvar |
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128 | la a0, 0(a1) |
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129 | beq a0, zero, noex |
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130 | nop |
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131 | EXIT(2) |
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132 | noex: |
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133 | li a0, 1 |
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134 | sw a0, 0(a1) |
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135 | lw a0, 4(sp) |
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136 | lw ra, 8(sp) |
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137 | addiu sp, sp, 8 |
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138 | eret |
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139 | /* we should not end there */ |
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140 | EXIT(1) |
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141 | |
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142 | .rodata: |
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143 | statusstr: .ascii "status \0" |
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144 | causestr: .ascii " cause \0" |
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145 | pcstr: .ascii " pc \0" |
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146 | badvastr: .ascii " badva \0" |
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147 | xicustr: .ascii " xicu \0" |
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148 | startstr: .ascii "start\n\0" |
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149 | endstr: .ascii "end \0" |
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150 | |
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151 | .org EXCEP_ADDRESS - BOOT_ADDRESS |
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152 | .globl evect |
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153 | evect: |
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154 | j excep |
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155 | nop |
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156 | /* |
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157 | * we use a ldscript trick here, to load this function at |
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158 | * the appropriate address |
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159 | */ |
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160 | .section .text2, "ax" |
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161 | .globl doload |
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162 | doload: |
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163 | la s0, testval |
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164 | jr ra |
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165 | lw a1, 0(s0) /* this should trigger the exception */ |
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166 | /* we should not get there */ |
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167 | EXIT(1) |
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168 | nop |
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169 | .data |
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170 | myvar: .word 0 |
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171 | testval: |
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172 | .word MAGIC2 |
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173 | .globl pte2 |
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174 | pte2: |
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175 | .align 12 |
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176 | .word PTE2_V | PTE2_C | PTE2_X |
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177 | .word BOOT_ADDRESS >> 12 |
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178 | .org pte2 + 4092 |
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179 | .globl pte22 |
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180 | pte22: |
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181 | .align 12 |
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182 | .word 0 |
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183 | .word 0 |
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184 | .org pte22 + 4092 |
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185 | .globl pte1 |
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186 | pte1: |
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187 | .align 13 |
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188 | .word PTE1_V | PTE1_C | PTE1_W | 0x0 /* map PA 0 at VA 0 */ |
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189 | .org pte1 + (DOLOAD_ADDR >> 21) * 4 |
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190 | .word PTE1_V | PTE1_T | (0x2000 >> 12) /* map VA DOLOAD_ADDR with 4k page: check real address of PTE22 !!! */ |
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191 | .org pte1 + (BOOT_ADDRESS >> 21) * 4 |
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192 | .word PTE1_V | PTE1_T | (0x1000 >> 12) /* map PA 0xbfc00000 at VA 0xbfc00000 with 4k page: check real address of PTE2 !!! */ |
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193 | .org pte1 + (TTY_BASE >> 21) * 4 |
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194 | .word PTE1_V | PTE1_W | (TTY_BASE >> 21) /* map PA 0xd0200000 at VA 0xd0200000 */ |
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195 | .org pte1 + (XICU_BASE >> 21) * 4 |
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196 | .word PTE1_V | PTE1_W | (XICU_BASE >> 21) /* map PA 0xd2000000 at VA 0xd2000000 */ |
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197 | .org pte1 + (EXIT_BASE >> 21) * 4 |
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198 | .word PTE1_V | PTE1_W | (EXIT_BASE >> 21) /* map PA 0xe0000000 at VA 0xe0000000 */ |
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199 | .org pte1 + 8192 |
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200 | .word 0 |
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201 | |
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