1 | /******************************************************************************** |
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2 | * File : reset.S |
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3 | * Author : Alain Greiner |
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4 | * Date : 15/01/2014 |
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5 | ********************************************************************************* |
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6 | * This is a boot code for a generic multi-clusters / multi-processors |
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7 | * TSAR architecture (up to 256 clusters / up to 4 processors per cluster). |
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8 | * The physical address is 40 bits, and the 8 MSB bits A[39:32] define the |
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9 | * cluster index. |
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10 | * |
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11 | * As we don't want to use the virtual memory, the physical address is |
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12 | * equal to the virtual address (identity mapping) and all processors stacks |
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13 | * and code segments are allocated in the physical memory bank in cluster 0. |
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14 | * |
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15 | * Both the reset base address and the kernel base address must be redefined |
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16 | * to use a physical memory bank smaller than 2 Gbytes. |
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17 | * |
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18 | * There is one XCU iand one MMC per cluster. |
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19 | * |
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20 | * There is one IOPIC component in cluster_io. |
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21 | * |
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22 | * There is two sets of peripherals: |
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23 | * |
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24 | * 1) A block device and a single channel TTY controller are available |
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25 | * in cluster(0,0). |
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26 | * |
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27 | * 2) Other peripherals (including another Blockdevice, a multi-channels TTY |
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28 | * contrÃŽler, a Frame buffer) are located in cluster_io. |
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29 | * For those externals peripherals, hardware interrupts (HWI) are translated |
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30 | * to software interrupts (WTI) by and IOPIC component, that is programmed |
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31 | * to route all SWI to to processor 0 in cluster (0,0). |
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32 | * |
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33 | * The boot sequence is the following: |
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34 | * - Each processor initializes the stack pointer ($29) depending on proc_id. |
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35 | * - Each processor initializes the CP0 EBASE register |
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36 | * - Only processor 0 initializes the Interrupt vector. |
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37 | * - Only processor 0 initializes the IOPIC component. |
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38 | * - Each processor initializes its private XCU mask. |
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39 | * - Each processor initializes the Status Register (SR) |
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40 | * - Each processor jumps to the same main address in kernel mode... |
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41 | ********************************************************************************/ |
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42 | |
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43 | #include "hard_config.h" |
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44 | #include "mips32_registers.h" |
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45 | |
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46 | .section .reset,"ax",@progbits |
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47 | |
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48 | .extern seg_stack_base |
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49 | .extern seg_xcu_base |
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50 | .extern seg_pic_base |
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51 | .extern seg_kcode_base |
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52 | .extern _interrupt_vector |
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53 | .extern _ioc_isr |
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54 | .extern _mmc_isr |
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55 | .extern _tty_isr |
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56 | .extern main |
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57 | |
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58 | .globl reset |
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59 | .ent reset |
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60 | .align 2 |
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61 | |
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62 | reset: |
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63 | .set noreorder |
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64 | |
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65 | /* each proc computes proc_id, lpid, cluster_xy */ |
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66 | mfc0 $26, CP0_PROCID |
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67 | andi $26, $26, 0x3FF /* at most 1024 processors */ |
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68 | move $10, $26 /* $10 <= proc_id */ |
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69 | li $27, NB_PROCS_MAX |
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70 | divu $26, $27 |
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71 | mfhi $11 /* $11 <= lpid */ |
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72 | mflo $12 /* $12 <= cluster_xy */ |
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73 | |
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74 | /* each proc initializes stack pointer (64K per processor) */ |
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75 | la $27, seg_stack_base |
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76 | addi $26, $10, 1 /* $26 <= (proc_id + 1) */ |
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77 | sll $26, $26, 14 /* $26 <= (proc_id + 1) * 16K */ |
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78 | addu $29, $27, $26 /* $29 <= seg_stack_base(proc_id) */ |
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79 | |
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80 | /* each proc initializes CP0 EBASE register */ |
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81 | la $26, seg_kcode_base |
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82 | mtc0 $26, CP0_EBASE /* CP0_EBASE <= seg_kcode_base */ |
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83 | |
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84 | /* only proc (0,0,0) initializes interrupt vector for IOC, TTY, MMC */ |
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85 | bne $10, $0, reset_xcu |
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86 | nop |
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87 | |
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88 | la $26, _interrupt_vector /* interrupt vector address */ |
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89 | la $27, _mmc_isr |
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90 | sw $27, 32($26) /* interrupt_vector[8] <= _mmc_isr */ |
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91 | la $27, _ioc_isr |
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92 | sw $27, 36($26) /* interrupt_vector[9] <= _ioc_isr */ |
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93 | la $27, _tty_isr |
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94 | sw $27, 40($26) /* interrupt_vector[10] <= _tty_isr */ |
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95 | |
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96 | /* only proc (0,0,0) initializes IOPIC : IOPIC_ADDRESS[i] <= &XICU[0].WTI_REG[i] */ |
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97 | |
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98 | li $20, X_SIZE |
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99 | addi $20, $20, -1 |
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100 | sll $20, $20, 4 |
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101 | li $21, Y_SIZE |
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102 | add $22, $20, $21 /* $22 <= cluster(X_SIZE-1, Y_SIZE) */ |
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103 | |
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104 | mtc2 $22, CP2_PADDR_EXT /* CP2_PADDR_EXT <= cluster_io */ |
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105 | |
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106 | li $24, 16 /* $24 iteration (de)counter */ |
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107 | la $27, seg_xcu_base /* $27 <= &(XICU[0].WTI_REG[0]) */ |
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108 | la $26, seg_pic_base /* $26 <= &IOPIC_ADDRESS[0] */ |
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109 | |
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110 | reset_loop: |
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111 | sw $27, 0($26) /* IOPIC_ADDRESS[i] <= &XICU[0].WTI_REG[i] */ |
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112 | addi $24, $24, -1 /* decrement iteration index */ |
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113 | addi $27, $27, 4 /* $27 <= &(XICU[0].WTI_REG[i++] */ |
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114 | addi $26, $26, 16 /* $26 <= &IOPIC_ADDRESS[i++] */ |
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115 | bne $24, $0, reset_loop |
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116 | nop |
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117 | |
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118 | mtc2 $0, CP2_PADDR_EXT /* CP2_PADDR_EXT <= zero */ |
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119 | |
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120 | reset_xcu: |
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121 | |
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122 | /* only proc (x,y,0) receive IRQs and initialise HWI and WTI XICU masks */ |
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123 | bne $11, $0, reset_end |
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124 | nop |
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125 | la $26, seg_xcu_base |
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126 | li $27, 0b010010000000 /* offset for MSK_HWI_ENABLE[lpid == 0] */ |
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127 | addu $24, $26, $27 /* $24 <= &HWI_MASK */ |
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128 | li $25, 0x0700 /* TTY:HWI[10] IOC:HWI[9] MEMC:HWI[8] */ |
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129 | sw $25, 0($24) /* set HWI mask */ |
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130 | |
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131 | li $27, 0b011010000000 /* offset for MSK_WTI_ENABLE[lpid == 0] */ |
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132 | addu $24, $26, $27 /* $24 <= $WTI_MASK */ |
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133 | li $25, 0xFFFFFFFF /* all WTI enabled */ |
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134 | sw $25, 0($24) /* set WTI mask */ |
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135 | |
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136 | reset_end: |
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137 | |
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138 | /* initializes SR register */ |
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139 | li $26, 0x0000FF01 |
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140 | mtc0 $26, $12 /* SR <= kernel mode / IRQ enable */ |
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141 | |
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142 | /* jumps to main in kernel mode */ |
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143 | la $26, main |
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144 | jr $26 |
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145 | nop |
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146 | |
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147 | .end reset |
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148 | |
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149 | .set reorder |
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