[1] | 1 | /************************************************************************************************* |
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| 2 | * This file contains the entry point of the ALMOS-MK boot-loader for TSAR architecture. * |
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| 3 | * It supports a generic multi-clusters / multi-processors architecture * |
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| 4 | * * |
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| 5 | * - The number of clusters is defined by the (X_SIZE, Y_SIZE) parameters in the * |
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| 6 | * hard_config.h file (up to 256 clusters). * |
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| 7 | * - The number of processors per cluster is defined by the NB_PROCS_MAX parameter in the * |
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| 8 | * hard_config.h file (up to 4 processors per cluster). * |
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| 9 | * * |
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| 10 | * This assembly code is executed by all cores. It has 2 versions (in order to see if the * |
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| 11 | * contention created by the ARCHINFO core descriptor table scanning loops is acceptable): * |
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| 12 | * with or without the assumption that the core hardware identifier gid has a fixed format: * |
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| 13 | * * |
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| 14 | * - Version with fixed format: gid == (((x << Y_WIDTH) + y) << PADDR_WIDTH) + lid * |
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| 15 | * It does 3 things: * |
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| 16 | * + It initializes the stack pointer depending on the lid extracted from the gid, * |
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| 17 | * using the BOOT_STACK_BASE and BOOT_STACK_SIZE parameters defined in the * |
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| 18 | * 'boot_config.h' file, * |
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| 19 | * + It changes the value of the address extension registers using the cxy extracted * |
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| 20 | * from the gid, * |
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| 21 | * + It jumps to the boot_loader() function defined in the 'boot.c' file and passes 2 * |
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| 22 | * arguments which are the cxy and lid of each core to this function. * |
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| 23 | * * |
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| 24 | * - Version without fixed format * |
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| 25 | * It has to perform an additional step in order to extract the (cxy,lid) values from the * |
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| 26 | * arch_info.bin structure that has been loaded in the cluster (0,0) memory by the bscpu. * |
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| 27 | * + Each core other than the bscpu scans the core descriptor table in the arch_info.bin * |
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| 28 | * structure to make an associative search on the (gid), and get the (cxy,lid). * |
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| 29 | * + It initializes the stack pointer depending on the lid, using the BOOT_STACK_BASE * |
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| 30 | * and BOOT_STACK_SIZE parameters defined in the 'boot_config.h' file, * |
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| 31 | * + It changes the value of the address extension registers using cxy obtained * |
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| 32 | * previously, * |
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| 33 | * + It jumps to the boot_loader() function defined in the 'boot.c' file and passes 2 * |
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| 34 | * arguments which are the cxy and lid of each core to this function. * |
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| 35 | *************************************************************************************************/ |
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| 36 | |
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| 37 | #include "mips32_registers.h" |
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| 38 | #include "hard_config.h" |
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| 39 | #include "boot_config.h" |
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| 40 | |
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| 41 | .section .text, "ax", @progbits |
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| 42 | |
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| 43 | .globl boot_entry |
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| 44 | .ent boot_entry |
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| 45 | |
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| 46 | .align 2 |
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| 47 | .set noreorder |
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| 48 | |
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| 49 | boot_entry: |
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| 50 | |
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| 51 | #if USE_FIXED_FORMAT |
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| 52 | |
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| 53 | /************* |
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| 54 | * VERSION 1 * |
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| 55 | *************/ |
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| 56 | |
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| 57 | /* |
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| 58 | * Get (cxy, lid) values from gid contained in coprocessor0 register. |
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| 59 | */ |
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| 60 | |
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| 61 | mfc0 k0, CP0_PROCID |
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| 62 | andi k0, k0, 0xFFF /* k0 <= gid */ |
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| 63 | andi t1, k0, ((1 << PADDR_WIDTH) - 1) /* t1 <= lid */ |
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| 64 | srl t2, k0, PADDR_WIDTH /* t2 <= cxy */ |
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| 65 | |
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| 66 | /* |
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| 67 | * Initializing stack pointer from previously retrieved lid value. |
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| 68 | */ |
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| 69 | |
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| 70 | la t0, BOOT_STACK_BASE /* t0 <= BOOT_STACK_BASE */ |
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| 71 | li k1, BOOT_STACK_SIZE /* k1 <= BOOT_STACK_SIZE */ |
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| 72 | multu k1, t1 |
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| 73 | mflo k0, /* k0 <= BOOT_STACK_SIZE * lid */ |
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| 74 | subu sp, t0, k0 /* P[cxy,lid] stack top initialized */ |
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| 75 | |
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| 76 | /* |
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| 77 | * Switching to local DSPACE by changing the value of the address extension registers. |
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| 78 | */ |
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| 79 | |
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| 80 | mtc2 t2, CP2_DATA_PADDR_EXT |
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| 81 | |
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| 82 | /* |
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| 83 | * Jumping to boot_loader() function after passing 2 arguments in the registers. |
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| 84 | */ |
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| 85 | |
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| 86 | or a0, zero, t1 /* a0 <= lid */ |
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| 87 | or a1, zero, t2 /* a1 <= cxy */ |
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| 88 | la ra, boot_loader |
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| 89 | jr ra |
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| 90 | nop |
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| 91 | |
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| 92 | #else |
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| 93 | |
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| 94 | /************* |
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| 95 | * VERSION 2 * |
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| 96 | *************/ |
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| 97 | |
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| 98 | /* |
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| 99 | * Testing if this is bscpu. |
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| 100 | */ |
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| 101 | |
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| 102 | mfc0 k0, CP0_PROCID |
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| 103 | andi k0, k0, 0xFFF /* k0 <= gid */ |
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| 104 | |
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| 105 | li t1, BOOT_CORE_GID /* t1 <= bscpu gid */ |
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| 106 | or t3, zero, zero /* t3 <= bscpu lid = 0 */ |
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| 107 | beq k0, t1, bscpu_exit /* if bscpu, skip scanning core tbl */ |
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| 108 | li t4, BOOT_CORE_CXY /* t4 <= bscpu cxy */ |
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| 109 | |
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| 110 | /* |
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| 111 | * Getting base address of the core descriptor table in 'arch_info.bin' file. |
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| 112 | */ |
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| 113 | |
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| 114 | la t0, ARCHINFO_BASE /* t0 <= ARCHINFO_BASE */ |
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| 115 | li t1, 0x80 /* t1 <= ARCHINFO_HEADER_SIZE */ |
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| 116 | addu t2, t0, t1 /* t2 <= ARCHINFO_CORE_BASE */ |
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| 117 | |
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| 118 | /* |
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| 119 | * Scanning the core descriptor table if this is not bscpu. TODO If not found? |
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| 120 | */ |
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| 121 | |
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| 122 | li t3, 0x8 /* t3 <= ARCHINFO_CORE_SIZE */ |
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| 123 | |
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| 124 | scanning_core_table: |
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| 125 | lw t1, 0(t2) /* t1 <= archinfo_core.gid */ |
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| 126 | bne t1, k0, scanning_core_table /* if (t1 != k0) => loop */ |
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| 127 | addu t2, t2, t3 /* t2 <= @ next archinfo_core */ |
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| 128 | |
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| 129 | /* |
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| 130 | * Getting (cxy, lid) values from the found core descriptor. |
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| 131 | */ |
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| 132 | |
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| 133 | lw t3, -8(t2) /* t3 <= lid */ |
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| 134 | lw t4, -4(t2) /* t4 <= cxy */ |
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| 135 | |
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| 136 | /* |
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| 137 | * Initializing stack pointer from previously retrieved lid value. |
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| 138 | */ |
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| 139 | |
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| 140 | bscpu_exit: |
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| 141 | la t0, BOOT_STACK_BASE /* t0 <= BOOT_STACK_BASE */ |
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| 142 | li k1, BOOT_STACK_SIZE /* k1 <= BOOT_STACK_SIZE */ |
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| 143 | multu k1, t3 |
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| 144 | mflo k0 /* k0 <= BOOT_STACK_SIZE * lid */ |
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| 145 | subu sp, t0, k0 /* P[cxy,lid] stack top initialized */ |
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| 146 | |
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| 147 | /* |
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| 148 | * Switching to local DSPACE by changing the value of the address extension registers. |
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| 149 | */ |
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| 150 | |
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| 151 | mtc2 t4, CP2_DATA_PADDR_EXT |
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| 152 | |
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| 153 | /* |
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| 154 | * Jumping to boot_loader() function after passing 2 arguments in the registers. |
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| 155 | */ |
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| 156 | |
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| 157 | or a0, zero, t3 /* a0 <= lid */ |
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| 158 | or a1, zero, t4 /* a1 <= cxy */ |
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| 159 | la ra, boot_loader |
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| 160 | jr ra |
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| 161 | nop |
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| 162 | |
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| 163 | #endif |
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| 164 | |
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| 165 | .end boot_entry |
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| 166 | |
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| 167 | .set reorder |
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