Linux/AM5708: Errata i878 workaround implementation

J-breeze

Part Number: AM5708

Tool/software: Linux

Hi Champs,

I'm going to use Linux SDK on AM5708 ARM core side.
So, could you please let know whether a linux drive implement workarounds for errata i878(MPU Lockup with Concurrent DMM and EMIF Accesses), or not?

Best regards,
J-breeze

over 6 years ago

0 RonB over 6 years ago

TI__Mastermind 30746 points

J-breeze,

Would you please confirm what version of the SDK you are using? Thanks.

0 Manisha Agrawal over 6 years ago in reply to RonB

TI__Mastermind 22946 points

Hi J-breeze,

The only workaround for the errata is not to have concurrent DMM and EMIF access. The Linux driver access the TILER memory space through DMA only.

Regards,
Manisha

0 Matthijs van Duin over 6 years ago in reply to Manisha Agrawal

Mastermind 8040 points

manisha said:
The only workaround for the errata is not to have concurrent DMM and EMIF access.

That seems like an odd thing to say when the errata document actually specifies a workaround (setting bits 1 and 2 of the undocumented MPUSS register at 0x482AF400)

0 Matthijs van Duin over 6 years ago in reply to Manisha Agrawal

Mastermind 8040 points

manisha said:
The Linux driver access the TILER memory space through DMA only.

Also, this is not true. Using a tiled DRM framebuffer (required to be able to use hardware rotation, used for xrandr by the xorg-video-omap driver) results in CPU access to TILER memory space.

0 J-breeze over 6 years ago in reply to Matthijs van Duin

Expert 1105 points

Hi,

Thank you for your support.
You mean that I don't have to care the workarounds if I don't use the tiled DRM framebuffer?

Best regards,
J-breeze

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Linux/AM5708: Errata i878 workaround implementation