1 | /* |
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2 | * Copyright (c) 2018 embedded brains GmbH |
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3 | |
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4 | * Copyright (c) 2015 University of York. |
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5 | * Hesham Almatary <hesham@alumni.york.ac.uk> |
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6 | * |
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7 | * Copyright (c) 2013, The Regents of the University of California (Regents). |
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8 | * All Rights Reserved. |
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9 | * |
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10 | * Redistribution and use in source and binary forms, with or without |
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11 | * modification, are permitted provided that the following conditions |
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12 | * are met: |
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13 | * 1. Redistributions of source code must retain the above copyright |
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14 | * notice, this list of conditions and the following disclaimer. |
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15 | * 2. Redistributions in binary form must reproduce the above copyright |
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16 | * notice, this list of conditions and the following disclaimer in the |
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17 | * documentation and/or other materials provided with the distribution. |
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18 | * |
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19 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND |
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20 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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21 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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22 | * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE |
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23 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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24 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
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25 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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26 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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27 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
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28 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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29 | * SUCH DAMAGE. |
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30 | */ |
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31 | |
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32 | #include <rtems/asm.h> |
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33 | #include <rtems/score/percpu.h> |
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34 | #include <rtems/score/riscv-utility.h> |
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35 | #include <bsp/linker-symbols.h> |
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36 | #include <bspopts.h> |
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37 | |
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38 | PUBLIC(_start) |
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39 | |
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40 | .section .bsp_start_text, "wax", @progbits |
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41 | .align 2 |
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42 | |
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43 | TYPE_FUNC(_start) |
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44 | SYM(_start): |
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45 | /* Load global pointer */ |
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46 | .option push |
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47 | .option norelax |
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48 | LADDR gp, __global_pointer$ |
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49 | .option pop |
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50 | |
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51 | /* Init FPU */ |
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52 | #ifdef __riscv_flen |
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53 | li t0, MSTATUS_FS |
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54 | csrs mstatus, t0 |
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55 | csrw fcsr, zero |
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56 | #endif |
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57 | |
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58 | /* Set exception handler */ |
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59 | LADDR t0, _RISCV_Exception_handler |
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60 | csrw mtvec, t0 |
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61 | |
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62 | /* Load stack pointer and branch to secondary processor start if necessary */ |
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63 | #ifdef RTEMS_SMP |
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64 | LADDR sp, _ISR_Stack_area_begin |
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65 | LADDR t2, _ISR_Stack_size |
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66 | csrr s0, mhartid |
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67 | LADDR t0, _Per_CPU_Information |
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68 | slli t1, s0, PER_CPU_CONTROL_SIZE_LOG2 |
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69 | add s1, t0, t1 |
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70 | csrw mscratch, s1 |
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71 | bnez s0, .Lstart_on_secondary_processor |
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72 | add sp, sp, t2 |
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73 | #else |
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74 | LADDR sp, _ISR_Stack_area_end |
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75 | #endif |
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76 | |
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77 | #ifdef BSP_START_COPY_FDT_FROM_U_BOOT |
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78 | mv a0, a1 |
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79 | call bsp_fdt_copy |
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80 | #endif |
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81 | |
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82 | /* Clear .bss */ |
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83 | LADDR a0, bsp_section_bss_begin |
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84 | li a1, 0 |
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85 | LADDR a2, bsp_section_bss_size |
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86 | call memset |
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87 | |
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88 | #ifdef RTEMS_SMP |
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89 | /* Give go to secondary processors */ |
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90 | LADDR t0, .Lsecondary_processor_go |
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91 | fence iorw,ow |
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92 | amoswap.w zero, zero, 0(t0) |
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93 | #endif |
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94 | |
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95 | j boot_card |
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96 | |
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97 | #ifdef RTEMS_SMP |
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98 | |
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99 | .Lstart_on_secondary_processor: |
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100 | |
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101 | /* Adjust stack pointer */ |
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102 | #ifdef __riscv_mul |
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103 | addi t0, s0, 1 |
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104 | mul t2, t2, t0 |
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105 | #else |
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106 | mv t0, s0 |
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107 | mv t3, t2 |
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108 | |
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109 | .Ladd_more: |
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110 | |
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111 | add t2, t2, t3 |
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112 | addi t0, t0, -1 |
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113 | bnez t0, .Ladd_more |
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114 | #endif |
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115 | add sp, sp, t2 |
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116 | |
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117 | /* Wait for go issued by the boot processor (mhartid == 0) */ |
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118 | LADDR t0, .Lsecondary_processor_go |
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119 | |
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120 | .Lwait_for_go_again: |
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121 | |
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122 | lw t1, 0(t0) |
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123 | fence iorw, iorw |
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124 | bnez t1, .Lwait_for_go_again |
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125 | |
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126 | mv a0, s1 |
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127 | call bsp_start_on_secondary_processor |
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128 | |
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129 | #if __riscv_xlen == 32 |
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130 | .align 2 |
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131 | #elif __riscv_xlen == 64 |
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132 | .align 3 |
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133 | #endif |
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134 | |
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135 | .Lsecondary_processor_go: |
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136 | |
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137 | /* |
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138 | * These are ebreak instructions, just in case we end up here executing |
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139 | * code. |
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140 | */ |
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141 | .word 0x00100073 |
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142 | #if __riscv_xlen == 64 |
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143 | .word 0x00100073 |
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144 | #endif |
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145 | |
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146 | #endif /* RTEMS_SMP */ |
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