1External Debug Support 2---------------------- 3 4Freescale's e500v1 and e500v2 cores (used in mpc85xx chips) have some 5restrictions on external debugging (JTAG). In particular, for the debugger to 6be able to receive control after a single step or breakpoint: 7 - MSR[DE] must be set 8 - A valid opcode must be fetchable, through the MMU, from the debug 9 exception vector (IVPR + IVOR15). 10 11To maximize the time during which this requirement is met, U-Boot sets MSR[DE] 12immediately on entry and keeps it set. It also uses a temporary TLB to keep a 13mapping to a valid opcode at the debug exception vector, even if we normally 14don't support exception vectors being used that early, and that's not the area 15where U-Boot currently executes from. 16 17Note that there may still be some small windows where debugging will not work, 18such as in between updating IVPR and IVOR15. 19 20Config Switches: 21---------------- 22 23Please refer README section "MPC85xx External Debug Support" 24 25Major Config Switches during various boot Modes 26---------------------------------------------- 27 28NOR boot 29 !defined(CONFIG_SYS_RAMBOOT) && !defined(CONFIG_SPL) 30NOR boot Secure 31 !defined(CONFIG_SYS_RAMBOOT) && defined(CONFIG_SECURE_BOOT) 32RAMBOOT(SD, SPI & NAND boot) 33 defined(CONFIG_SYS_RAMBOOT) 34RAMBOOT Secure (SD, SPI & NAND) 35 defined(CONFIG_SYS_RAMBOOT) && defined(CONFIG_SECURE_BOOT) 36NAND SPL BOOT 37 defined(CONFIG_SYS_RAMBOOT) && defined(CONFIG_NAND_SPL) 38 39 40TLB Entries during u-boot execution 41----------------------------------- 42 43Note: Sequence number is in order of execution 44 45A) defined(CONFIG_SYS_RAMBOOT) i.e. SD, SPI, NAND RAMBOOT & NAND_SPL boot 46 47 1) TLB entry to overcome e500 v1/v2 debug restriction 48 Location : Label "_start_e500" 49 TLB Entry : CONFIG_SYS_PPC_E500_DEBUG_TLB 50 EPN -->RPN : CONFIG_SYS_MONITOR_BASE --> CONFIG_SYS_MONITOR_BASE 51 Properties : 256K, AS0, I, IPROT 52 53 2) TLB entry for working in AS1 54 Location : Label "create_init_ram_area" 55 TLB Entry : 15 56 EPN -->RPN : CONFIG_SYS_MONITOR_BASE --> CONFIG_SYS_MONITOR_BASE 57 Properties : 1M, AS1, I, G, IPROT 58 59 3) TLB entry for the stack during AS1 60 Location : Lable "create_init_ram_area" 61 TLB Entry : 14 62 EPN -->RPN : CONFIG_SYS_INIT_RAM_ADDR --> CONFIG_SYS_INIT_RAM_ADDR 63 Properties : 16K, AS1, IPROT 64 65 4) TLB entry for CCSRBAR during AS1 execution 66 Location : cpu_init_early_f 67 TLB Entry : 13 68 EPN -->RPN : CONFIG_SYS_CCSRBAR --> CONFIG_SYS_CCSRBAR 69 Properties : 1M, AS1, I, G 70 71 5) Invalidate unproctected TLB Entries 72 Location : cpu_init_early_f 73 Invalidated: 13 74 75 6) Create TLB entries as per boards/freescale/<board>/tlb.c 76 Location : cpu_init_early_f --> init_tlbs() 77 Properties : ..., AS0, ... 78 Please note It can overwrites previous TLB Entries. 79 80 7) Disable TLB Entries of AS1 81 Location : cpu_init_f --> disable_tlb() 82 Disable : 15, 14 83 84 8) Update Flash's TLB entry 85 Location : Board_init_r 86 TLB entry : Search from TLB entries 87 EPN -->RPN : CONFIG_SYS_FLASH_BASE --> CONFIG_SYS_FLASH_BASE_PHYS 88 Properties : Board specific size, AS0, I, G, IPROT 89 90 91B) !defined(CONFIG_SYS_RAMBOOT) i.e. NOR boot 92 93 1) TLB entry to overcome e500 v1/v2 debug restriction 94 Location : Label "_start_e500" 95 TLB Entry : CONFIG_SYS_PPC_E500_DEBUG_TLB 96#if defined(CONFIG_SECURE_BOOT) 97 EPN -->RPN : CONFIG_SYS_MONITOR_BASE --> CONFIG_SYS_PBI_FLASH_WINDOW 98 Properties : 1M, AS1, I, G, IPROT 99#else 100 EPN -->RPN : CONFIG_SYS_MONITOR_BASE & 0xffc00000 --> 0xffc00000 101 Properties : 4M, AS0, I, G, IPROT 102#endif 103 104 2) TLB entry for working in AS1 105 Location : Label "create_init_ram_area" 106 TLB Entry : 15 107#if defined(CONFIG_SECURE_BOOT) 108 EPN -->RPN : CONFIG_SYS_MONITOR_BASE --> CONFIG_SYS_PBI_FLASH_WINDOW 109 Properties : 1M, AS1, I, G, IPROT 110#else 111 EPN -->RPN : CONFIG_SYS_MONITOR_BASE & 0xffc00000 --> 0xffc00000 112 Properties : 4M, AS1, I, G, IPROT 113#endif 114 115 3) TLB entry for the stack during AS1 116 Location : Lable "create_init_ram_area" 117 TLB Entry : 14 118 EPN -->RPN : CONFIG_SYS_INIT_RAM_ADDR --> CONFIG_SYS_INIT_RAM_ADDR 119 Properties : 16K, AS1, IPROT 120 121 4) TLB entry for CCSRBAR during AS1 execution 122 Location : cpu_init_early_f 123 TLB Entry : 13 124 EPN -->RPN : CONFIG_SYS_CCSRBAR --> CONFIG_SYS_CCSRBAR 125 Properties : 1M, AS1, I, G 126 127 5) TLB entry for Errata workaround CONFIG_SYS_FSL_ERRATUM_IFC_A003399 128 Location : cpu_init_early_f 129 TLB Entry : 9 130 EPN -->RPN : SRAM_BASE_ADDR --> SRAM_BASE_ADDR 131 Properties : 1M, AS1, I 132 133 6) CONFIG_SYS_FSL_ERRATUM_IFC_A003399 Adjust flash's phys addr 134 Location : cpu_init_early_f --> setup_ifc 135 TLB Entry : Get Flash TLB 136 EPN -->RPN : Adjusted flash_phys --> Adjusted flash_phys 137 Properties : 4M, AS1, I, G, IPROT 138 139 7) CONFIG_SYS_FSL_ERRATUM_IFC_A003399: E500 v1,v2 debug restriction 140 Location : cpu_init_early_f --> setup_ifc 141 TLB Entry : CONFIG_SYS_PPC_E500_DEBUG_TLB 142 EPN -->RPN : Adjusted flash_phys --> Adjusted flash_phys 143 Properties : 4M, AS0, I, G, IPROT 144 145 8) Invalidate unproctected TLB Entries 146 Location : cpu_init_early_f 147 Invalidated: 13, 9 148 149 9) Create TLB entries as per boards/freescale/<board>/tlb.c 150 Location : cpu_init_early_f --> init_tlbs() 151 Properties : ..., AS0, ... 152 Note: It can overwrites previous TLB Entries 153 154 10) Disable TLB Entries of AS1 155 Location : cpu_init_f --> disable_tlb() 156 Disable : 15, 14 157 158 11) Create DDR's TLB entriy 159 Location : Board_init_f -> init_func_ram -> initdram 160 TLB entry : Search free TLB entry 161 162 12) Update Flash's TLB entry 163 Location : Board_init_r 164 TLB entry : Search from TLB entries 165 EPN -->RPN : CONFIG_SYS_FLASH_BASE --> CONFIG_SYS_FLASH_BASE_PHYS 166 Properties : Board specific size, AS0, I, G, IPROT 167