This describes requirement of e500 and e500v2 processor to support external debugger.

It also provide an insight of the configuration switch required and their description.

Signed-off-by: Radu Lazarescu radu.lazarescu@freescale.com Signed-off-by: Marius Grigoras marius.grigoras@freescale.com Signed-off-by: Prabhakar Kushwaha prabhakar@freescale.com --- Based upon git://git.denx.de/u-boot.git branch master

Changes for v2: - Recreated README.mpc85xx - Added #define in README

Changes for v3: Incorporated Scott's comments - Moved config switch to "85xx CPU options" - Added TLB entry information

Tested on - SoC having E500 Family processor (P1010RDB, BSC9131RDB) - SoC having E500MC Family processor (P4080DS, P3041DS)

README | 9 +++ doc/README.mpc85xx | 161 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 170 insertions(+), 0 deletions(-) create mode 100644 doc/README.mpc85xx

diff --git a/README b/README index 1f8bd20..37d814b 100644 --- a/README +++ b/README @@ -374,6 +374,15 @@ The following options need to be configured: Defines the string to utilize when trying to match PCIe device tree nodes for the given platform.

+ CONFIG_SYS_PPC_E500_DEBUG_TLB + + Enables a temporary TLB entry to be used during boot to work + around limitations in e500v1 and e500v2 external debugger + support. This reduces the portions of the boot code where + breakpoints and single stepping do not work. The value of this + symbol should be set to the TLB1 entry to be used for this + purpose. + - Intel Monahans options: CONFIG_SYS_MONAHANS_RUN_MODE_OSC_RATIO

diff --git a/doc/README.mpc85xx b/doc/README.mpc85xx new file mode 100644 index 0000000..3942477 --- /dev/null +++ b/doc/README.mpc85xx @@ -0,0 +1,161 @@ +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) +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 + EPN -->RPN : CONFIG_SYS_MONITOR_BASE & 0xffc00000 --> 0xffc00000 + Properties : 4M, AS0, I, G,IPROT + + 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