Transcript Presentation Title Here
Debug TI Keystone II U-Boot with CCSv5
Vincent Han Mar, 2014
1 TI Information – Selective Disclosure
Agenda
• Basic U-boot Code Structure • Debug on TCI6638EVM with CCSv5
TI Information – Selective Disclosure 2
Basic Keystone II U-boot Code Structure
start.S
crt0.S
board.c
\tci6638_evm\ board.c
_start: ...
bl _main _main: ...
bl board_init_f ...
b relocate_code } { board_init_f() ...
board_early_init_f ...
} { board_early_init_f() ...
relocate_code: ...
...
ld pc, = board_init_r { board_init_r() ...
} TI Information – Selective Disclosure
U-boot Relocation Mechanism
• U-boot designs the HW initialization as 2 parts – 1 st part is function “board_init_f” – 2 nd part is function “board_init_r” • There will be sections’ relocation operation during these 2 steps • Benefits of this design: – Can implement on some platforms have little on-chip SRAM to run entire image (e.g. have little size of on-chip memory but have enough room on DDR) – Can improve the code execute efficiency (e.g. first run on Flash then relocate the code and run on SRAM) • Although Keystone II devices have enough on-chip SRAM ,the Keystone II U-boot code still keeps this mechanism TI Information – Selective Disclosure
U-boot Relocation Procedures - 1
PC MSMC SRAM U-boot Image board_init_f relocate_code board_init_r Initialize DDR DDR SRAM (Not initialized) … TI Information – Selective Disclosure
U-boot Relocation Procedures - 2
PC MSMC SRAM U-boot Image board_init_f relocate_code board_init_r Copy sections to DDR DDR SRAM (Initialized) … U-boot Image board_init_f relocate_code board_init_r … TI Information – Selective Disclosure
U-boot Relocation Procedures - 3
PC MSMC SRAM U-boot Image board_init_f relocate_code board_init_r DDR SRAM (Initialized) … PC U-boot Image board_init_f relocate_code board_init_r Not use anymore can release for others … TI Information – Selective Disclosure
Agenda
• Basic U-boot Code Structure • Debug on TCI6638EVM with CCSv5
TI Information – Selective Disclosure 8
Debug on TCI6638EVM with CCSv5
• Launch the debug session and connect the target – Please do not use any ARM core gel file – Connect with the 1 st ARM core on TCI6638 (other 3 cores are power-off after reset) • Load symbol to the target – After you load the symbol table, some of the symbols/functions which defined in U-boot image can be recognized by CCS • Load bin file to the target – Choose the load address “0x0C00_1000” and choose the 32-bit load mode • Change PC and map code in CCS – Add PC pointer in expression view and force PC pointer point to “0x0C00_1000” – Step into/over in the disassembly view by clicking green buttons until the PC pointer point to “board_init_f” TI Information – Selective Disclosure
Debug on TCI6638EVM with CCSv5
– Click “step into” to go to this function, you will see the following hints in code view window – Click “Locate File” to locate the correct path of board.c on your PC – Then you can debug the first part of hardware configurations code calling in function “board_init_f” • Get the relocate address from code – Function “board_init_f” will calculate the relocation address and store it in “id >relocaddr ”, we can get this value in the end part of this function • Remap code in CCS for relocation – After the relocation, the disassembly pointer and source code pointer will not be match with each other, which need our manually adjust to correct offset – We need to run just before calling “relocate_code” in function “_main” by setting the hardware breakpoint TI Information – Selective Disclosure
Debug on TCI6638EVM with CCSv5
– Then reload the symbol by adding the previous offset “0xBFF5_6000” to get the correct source code and disassembly pointer after the relocation for further debugging – The code and disassembly pointer will adjust to the correct place after relocation – We can switch to the correct address of “board_init_r” and make a hardware breakpoint in that place, then execute the code to stop at that breakpoint – We need to make the breakpoint at the adjusted address rather than the address before the relocation, or the breakpoint point to the different place and cannot stop correctly – We can see that after we stopped after relocation, the assembly code seemed incorrect due to the CCS disassembly view window parse the code in 32-bit ARM mode other than 16-bit Thumb mode, which needs us manually change the disassembly code view to Thumb mode – After this step, you can move on to debug the U-boot code in CCS by step into/over • For more information, please refer operation guide on deyisupport TI Information – Selective Disclosure
Boot Linux Kernel (UBI File-system)
• For the next boot procedure, if you configured the environment variables correctly, U-Boot will boot Linux Kernel automatically by default.
• Using UBI file-system, Linux Kernel, Boot Monitor and DTB files will be burnt on NAND flash, Ethernet is not needed during every boot time.
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TI Information – Selective Disclosure