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Altera_Forum's avatar
Altera_Forum
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13 years ago

cacheable PCIe BAR

Is it possible to make BAR cacheable for PCIe hard macro on Stratix IV attached to standard PC with Intel processor? Anything special needs to be done in the driver for such case? Thanks!
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
13 years ago

Thanks for the pointer to the tool! We have similar thing - dll for tcl which is quite flexible and convenient.

I tried to use CentOS 6 (2.6.32), which actually has support for PAT, write-combining and has ioremp_cache() function.

Write-combining/non-temporal writes (AVX/SSE) work as expected.

Reads work as expected when PCI BAR is mmaped as cached. Non-temporal full cache line writes work as expected in this case. However, simple writes still cause the system to freeze and then to reboot.

I also tried to do ioremp_cache() and then iowrite32() in the driver code and this also causes system freeze/reboot.

The system Sandy Bridge i7.