TMS320DM8147: u-boot accesses undocumented registers

Stephen Turner

Genius 3235 points

Part Number: TMS320DM8147
Other Parts Discussed in Thread: CCSTUDIO

We have noticed that the 814x u-boot is manipulating registers that don't seem to be documented in the TRM

For instance the following is defined in u-boot-omap3\arch\arm\include\asm\arch-ti81xx\cpu.h

Line 427: #define CM_DEFAULT_L3_FAST_CLKSTCTRL (PRCM_BASE + 0x0508)

and u-boot has code that does things like (in ddr2.c):

/*Enable the Power Domain Transition of L3 Fast Domain Peripheral */
__raw_writel(0x2, CM_DEFAULT_L3_FAST_CLKSTCTRL);

However, the TRM documents only a subset of these. See section 2.10.7

Is the u-boot code incorrect?. Or is the TRM incorrect?

thanks

0 Pavel Botev over 4 years ago

Hi Stephen,

From what I was able to find, u-boot is correct. Seems that this CM_DEFAULT_L3_FAST_CLKSTCTRL register is missing from DM814x TRM.

We have this register also in

1. Mistral DM814x EVM Diagnostics Software package

CCS_Code_BB/src/CCS_Test_code/GEL/PG2.1_DM814X_20Mhz_Si.gel.gel

CCS_Code_BB/src/CCS_Test_code/Base_Board/Integrated_Baseboard_Tests/GEL/DM814X_2_x.gel

IO_EXPANSION_BOARD_Rev_D/src/CCS_Test_Code/GEL/TI814x_ES_2x_evm_A8_ddr3_iss.gel

IO_EXPANSION_BOARD_Rev_D/src/CCS_Test_Code/IOExpansion_Application/MT9P031_Camera/TI814x_ES_2x_evm_A8_ddr3_iss.gel

2. In CCStudio GEL file, CCS v9.0.1

ccs/ccs_base/emulation/boards/dm814x_evm/gel/DM8148_EVM.gel

Regards,
Pavel

0 Stephen Turner over 4 years ago in reply to Pavel Botev

Genius 3235 points

Hi Pavel,

Does TI have any documentation other than u-boot or GEL code that describes the functionality of the CM_DEFAULT_L3_FAST_CLKSTCTRL register?

thanks

0 Pavel Botev over 4 years ago in reply to Stephen Turner

Stephen,

You can refer to DM816x TRM, section 18.7.6.2 CM_DEFAULT_L3_FAST_CLKSTCTRL Register

Regards,
Pavel

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