Re: [PATCH] fpga: altera-cvp: Truncated bitstream error support

From: tien . sung . ang
Date: Thu May 19 2022 - 05:39:46 EST


Thanks for bringing this up. Yes, you are right that the fpga_mgr sees this
as an error irrespective of the value. The CvP driver is changed now to just
indicate the correct error which recommends a retry. To me understanding,
EAGAIN was this. The fpga manager now looks like is going to return a CvP
failure in short.
A BUSY state does not seem to be able to solve this issue.
Even an extended time-out didn't resolve this error state. The current time-out
is set to 10seconds.
However, the main objective is to also handle the error if the CvP firmware
is not responsive. The error_path flow is to reset the CVP mode and HIP_CLK_SEL bit
as recommended by the firmware engineers.
The flow prescribed here is also an identical copy of working CvP driver
which is also owned by Intel. This driver is a downstream driver which is
not part of the Linux kernel. We are now porting this differences over to
the current upstream CvP driver.