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Diffstat (limited to 'qemu/roms/u-boot/doc/README.mpc85xx')
| -rw-r--r-- | qemu/roms/u-boot/doc/README.mpc85xx | 166 |
1 files changed, 166 insertions, 0 deletions
diff --git a/qemu/roms/u-boot/doc/README.mpc85xx b/qemu/roms/u-boot/doc/README.mpc85xx new file mode 100644 index 000000000..f9b023f28 --- /dev/null +++ b/qemu/roms/u-boot/doc/README.mpc85xx @@ -0,0 +1,166 @@ +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 |