How to read data from memory with linux 4.4.12

JoBr

Hi,

I'm using the AM57xx with "ti-processor-sdk-linux-rt-am57xx-evm-03.00.00.04" and linux-rt-4.4.12.

In the ti-ethernet-driver (prueth.c) I want to read some data from the Shared Memory of PRU. How can I do that?

At linux 3.2.0 there was something like READ_HWREG_PADDR to read data via virtual address. I can't find in linux 4.4.12.

I tried to use "memcpy_fromio" but I got an error (Unable to handle kernel NULL pointer...)

over 9 years ago

0 Biser Gatchev-XID over 9 years ago

TI__Guru**** 393215 points

Hi,

Have you tried with devmem2 ?

0 JoBr over 9 years ago in reply to Biser Gatchev-XID

Prodigy 30 points

Hi,

devmem2 is a tool to read/write.

I want to load data from memory and use this data in my code. So I'm looking for a pre-configured function or similar in Linux.

Are there possibilities?

0 Cvetolin Shulev-XID over 9 years ago

TI__Guru 65405 points

Hi JoBr,

There are many differences between kernel 3.2.0 and 4.4.12 but you can use "memcpy_fromio" function to read from memory. You can find an example about how to use this function in the
/board-support/linux-4.4.12+gitAUTOINC+3639bea54a-g3639bea54a/drivers/net/ethernet/ti/prueth.c file row 995.
Also you can obtain some details about PRU-ICSS Ethernet from the linked article:
processors.wiki.ti.com/.../PRU-ICSS_Ethernet

BR
Tsvetolin Shulev