External Debug Support ---------------------- Freescale's e500v1 and e500v2 cores (used in mpc85xx chips) have some restrictions on external debugging (JTAG). In particular, for the debugger to be able to receive control after a single step or breakpoint: - MSR[DE] must be set - A valid opcode must be fetchable, through the MMU, from the debug exception vector (IVPR + IVOR15). To maximize the time during which this requirement is met, U-Boot sets MSR[DE] immediately on entry and keeps it set. It also uses a temporary TLB to keep a mapping to a valid opcode at the debug exception vector, even if we normally don't support exception vectors being used that early, and that's not the area where U-Boot currently executes from. Note that there may still be some small windows where debugging will not work, such as in between updating IVPR and IVOR15. Config Switches: ---------------- Please refer README section "MPC85xx External Debug Support" Major Config Switches during various boot Modes ---------------------------------------------- NOR boot !defined(CONFIG_SYS_RAMBOOT) && !defined(CONFIG_SPL) NOR boot Secure !defined(CONFIG_SYS_RAMBOOT) && defined(CONFIG_SECURE_BOOT) RAMBOOT(SD, SPI & NAND boot) defined(CONFIG_SYS_RAMBOOT) RAMBOOT Secure (SD, SPI & NAND) defined(CONFIG_SYS_RAMBOOT) && defined(CONFIG_SECURE_BOOT) NAND SPL BOOT defined(CONFIG_SYS_RAMBOOT) && defined(CONFIG_NAND_SPL) TLB Entries during u-boot execution ----------------------------------- Note: Sequence number is in order of execution A) defined(CONFIG_SYS_RAMBOOT) i.e. SD, SPI, NAND RAMBOOT & NAND_SPL boot 1) TLB entry to overcome e500 v1/v2 debug restriction Location : Label "_start_e500" TLB Entry : CONFIG_SYS_PPC_E500_DEBUG_TLB EPN -->RPN : CONFIG_SYS_MONITOR_BASE --> CONFIG_SYS_MONITOR_BASE Properties : 256K, AS0, I, IPROT 2) TLB entry for working in AS1 Location : Label "create_init_ram_area" TLB Entry : 15 EPN -->RPN : CONFIG_SYS_MONITOR_BASE --> CONFIG_SYS_MONITOR_BASE Properties : 1M, AS1, I, G, IPROT 3) TLB entry for the stack during AS1 Location : Lable "create_init_ram_area" TLB Entry : 14 EPN -->RPN : CONFIG_SYS_INIT_RAM_ADDR --> CONFIG_SYS_INIT_RAM_ADDR Properties : 16K, AS1, IPROT 4) TLB entry for CCSRBAR during AS1 execution Location : cpu_init_early_f TLB Entry : 13 EPN -->RPN : CONFIG_SYS_CCSRBAR --> CONFIG_SYS_CCSRBAR Properties : 1M, AS1, I, G 5) Invalidate unproctected TLB Entries Location : cpu_init_early_f Invalidated: 13 6) Create TLB entries as per boards/freescale/<board>/tlb.c Location : cpu_init_early_f --> init_tlbs() Properties : ..., AS0, ... Please note It can overwrites previous TLB Entries. 7) Disable TLB Entries of AS1 Location : cpu_init_f --> disable_tlb() Disable : 15, 14 8) Update Flash's TLB entry Location : Board_init_r TLB entry : Search from TLB entries EPN -->RPN : CONFIG_SYS_FLASH_BASE --> CONFIG_SYS_FLASH_BASE_PHYS Properties : Board specific size, AS0, I, G, IPROT B) !defined(CONFIG_SYS_RAMBOOT) i.e. NOR boot 1) TLB entry to overcome e500 v1/v2 debug restriction Location : Label "_start_e500" TLB Entry : CONFIG_SYS_PPC_E500_DEBUG_TLB #if defined(CONFIG_SECURE_BOOT) EPN -->RPN : CONFIG_SYS_MONITOR_BASE --> CONFIG_SYS_PBI_FLASH_WINDOW Properties : 1M, AS1, I, G, IPROT #else EPN -->RPN : CONFIG_SYS_MONITOR_BASE & 0xffc00000 --> 0xffc00000 Properties : 4M, AS0, I, G, IPROT #endif 2) TLB entry for working in AS1 Location : Label "create_init_ram_area" TLB Entry : 15 #if defined(CONFIG_SECURE_BOOT) EPN -->RPN : CONFIG_SYS_MONITOR_BASE --> CONFIG_SYS_PBI_FLASH_WINDOW Properties : 1M, AS1, I, G, IPROT #else EPN -->RPN : CONFIG_SYS_MONITOR_BASE & 0xffc00000 --> 0xffc00000 Properties : 4M, AS1, I, G, IPROT #endif 3) TLB entry for the stack during AS1 Location : Lable "create_init_ram_area" TLB Entry : 14 EPN -->RPN : CONFIG_SYS_INIT_RAM_ADDR --> CONFIG_SYS_INIT_RAM_ADDR Properties : 16K, AS1, IPROT 4) TLB entry for CCSRBAR during AS1 execution Location : cpu_init_early_f TLB Entry : 13 EPN -->RPN : CONFIG_SYS_CCSRBAR --> CONFIG_SYS_CCSRBAR Properties : 1M, AS1, I, G 5) TLB entry for Errata workaround CONFIG_SYS_FSL_ERRATUM_IFC_A003399 Location : cpu_init_early_f TLB Entry : 9 EPN -->RPN : SRAM_BASE_ADDR --> SRAM_BASE_ADDR Properties : 1M, AS1, I 6) CONFIG_SYS_FSL_ERRATUM_IFC_A003399 Adjust flash's phys addr Location : cpu_init_early_f --> setup_ifc TLB Entry : Get Flash TLB EPN -->RPN : Adjusted flash_phys --> Adjusted flash_phys Properties : 4M, AS1, I, G, IPROT 7) CONFIG_SYS_FSL_ERRATUM_IFC_A003399: E500 v1,v2 debug restriction Location : cpu_init_early_f --> setup_ifc TLB Entry : CONFIG_SYS_PPC_E500_DEBUG_TLB EPN -->RPN : Adjusted flash_phys --> Adjusted flash_phys Properties : 4M, AS0, I, G, IPROT 8) Invalidate unproctected TLB Entries Location : cpu_init_early_f Invalidated: 13, 9 9) Create TLB entries as per boards/freescale/<board>/tlb.c Location : cpu_init_early_f --> init_tlbs() Properties : ..., AS0, ... Note: It can overwrites previous TLB Entries 10) Disable TLB Entries of AS1 Location : cpu_init_f --> disable_tlb() Disable : 15, 14 11) Create DDR's TLB entriy Location : Board_init_f -> init_func_ram -> initdram TLB entry : Search free TLB entry 12) Update Flash's TLB entry Location : Board_init_r TLB entry : Search from TLB entries EPN -->RPN : CONFIG_SYS_FLASH_BASE --> CONFIG_SYS_FLASH_BASE_PHYS Properties : Board specific size, AS0, I, G, IPROT