Linux/AM5708: GPMC communication issue with external peripheral

Narayanan Govind

Part Number: AM5708

Tool/software: Linux

Hi,

We are using custom AM5708 and FPGA, NVSRAM interfaced with it via GPMC and planning to go with latest TIs SDK.

Our team tried to configure GPMC at u-boot to access FPGA and NVSRAM memory region but no luck, getting random data when try to read either FPGA/NVSRAM memory region.

I came to know that we can configure GPMC either at u-boot or linux level and i am trying to configure gpmc at linux now. I have couple of doubts.

1. To configure gpmc at linux, do we need to apply gpmc pinmux in corresponding dts file of linux ? or is it okay to place them at mux_data.h of u-boot file?

2. In SDK we have gpmc basic configurations at dra7.dtsi. How to create child nodes for FPGA/NVSRAM in our custom dts file? Do you have any example for that?

3. What are the changes we need to take care to access FPGA/NVSRAM from linux apart from device tree file? do we need to change driver level code in latest SDK?

" GPMC using asynchronous non multiplexed and nor protocol mode".

I hope we can move forward based on your points on this issue.

Best Regards,

Narayanan

over 7 years ago

0 Narayanan Govind over 7 years ago

Prodigy 120 points

Hello Champs,

Can some one please respond?

0 Krunal Bhargav34 over 7 years ago in reply to Narayanan Govind

TI__Mastermind 45035 points

Hello Narayanan,

Please use the following thread as a reference.

Regards,

Krunal

0 Narayanan Govind over 7 years ago in reply to Krunal Bhargav34

Prodigy 120 points

Thanks for the reference Krunal.

I have GPMC configurations values for FPGA(CS2) and NVSRAM(CS3).

For FPGA:

GPMC_CONFIG1 = 0x02001013,
GPMC_CONFIG2 = 0x00040000,
GPMC_CONFIG3 = 0x00000000,
GPMC_CONFIG4 = 0x0f012001,
GPMC_CONFIG5 = 0x020f1215,
GPMC_CONFIG6 = 0x0e0702c2,
GPMC_CONFIG 7 =0x00000f52

For NVSRAM:

GPMC_CONFIG1 = 0x00000003,
GPMC_CONFIG2 = 0x00141000,
GPMC_CONFIG3 = 0x00000000,
GPMC_CONFIG4 = 0x0f011001,
GPMC_CONFIG5 = 0x020e1212,
GPMC_CONFIG6 = 0x0e0702c2,
GPMC_CONFIG 7 =0x00000f53

Could you please help me to find the way to convert those parameters to gpmc timing parameters for our custom device tree.

Best Regards,
Narayanan

0 Krunal Bhargav34 over 7 years ago in reply to Narayanan Govind

TI__Mastermind 45035 points

Hello Narayanan,

I am assuming your questions were addressed in the following thread. I will be closing the ticket and if you are still experiencing issues, please feel free to open the ticket in the future.

Regards,

Krunal

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Linux/AM5708: GPMC communication issue with external peripheral