167 lines
		
	
	
		
			5.8 KiB
		
	
	
	
		
			Plaintext
		
	
	
	
			
		
		
	
	
			167 lines
		
	
	
		
			5.8 KiB
		
	
	
	
		
			Plaintext
		
	
	
	
| 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_NXP_ESBC)
 | |
| RAMBOOT(SD, SPI & NAND boot)
 | |
| 		 defined(CONFIG_SYS_RAMBOOT)
 | |
| RAMBOOT Secure (SD, SPI & NAND)
 | |
| 		 defined(CONFIG_SYS_RAMBOOT) && defined(CONFIG_NXP_ESBC)
 | |
| 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"
 | |
|        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"
 | |
|        TLB Entry  : CONFIG_SYS_PPC_E500_DEBUG_TLB
 | |
| #if defined(CONFIG_NXP_ESBC)
 | |
|        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_NXP_ESBC)
 | |
|        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 -> dram_init
 | |
|        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
 |