win32: Cache invalidate

Question

MAORVERED MAORVERED 21

Hello,

I have to invalidate cache in a specified region.

I suspect that new data coming via DMA to RAM is not updated because the data is in cache.

If there a win32 code for this purpose ?

Thank you,

Zvika

Rita Han - MSFT 2,171 Reputation points

2021-01-05T06:35:48.357+00:00

Hello @MAORVERED MAORVERED , since you mentioned DMA and cache, so I want to confirm if you are developing drivers?
MAORVERED MAORVERED 21 Reputation points

2021-01-05T07:55:19.013+00:00

Hello,

Yes, I developed a device driver that initiates a DMA from FPGA to RAM.
I wonder if in the win32 application, I should invalidate the cache.

Thank you,
Zvika
Rita Han - MSFT 2,171 Reputation points

2021-01-05T08:15:27.49+00:00

For win32 application, if you are talking about file operations, you can turn off cache at the time the file is opened by passing FILE_FLAG_NO_BUFFERING as a value for the dwFlagsAndAttributes parameter of CreateFile. For driver related issue you can add windows-hardware-wdk-general tag for getting more professional support from driver expects.
MAORVERED MAORVERED 21 Reputation points

2021-01-05T08:17:29.723+00:00

Hello,

The issue regards to RAM, not to file operations.

Thank you,
Zvika
Rita Han - MSFT 2,171 Reputation points

2021-01-05T08:46:08.59+00:00

What operations to the RAM or what APIs do you use in your win32 application?
Viorel 122.6K Reputation points

2021-01-05T09:03:21.503+00:00

Maybe you should consider INVD and WBINVD instructions in case of corresponding microprocessors or check the technical documentation about preventing caching.

Your answer

Rita Han - MSFT 2,171 Reputation points

2021-01-05T06:35:48.357+00:00

Hello @MAORVERED MAORVERED , since you mentioned DMA and cache, so I want to confirm if you are developing drivers?
MAORVERED MAORVERED 21 Reputation points

2021-01-05T07:55:19.013+00:00

Hello,

Yes, I developed a device driver that initiates a DMA from FPGA to RAM.
I wonder if in the win32 application, I should invalidate the cache.

Thank you,
Zvika
Rita Han - MSFT 2,171 Reputation points

2021-01-05T08:15:27.49+00:00

For win32 application, if you are talking about file operations, you can turn off cache at the time the file is opened by passing FILE_FLAG_NO_BUFFERING as a value for the dwFlagsAndAttributes parameter of CreateFile. For driver related issue you can add windows-hardware-wdk-general tag for getting more professional support from driver expects.
MAORVERED MAORVERED 21 Reputation points

2021-01-05T08:17:29.723+00:00

Hello,

The issue regards to RAM, not to file operations.

Thank you,
Zvika
Rita Han - MSFT 2,171 Reputation points

2021-01-05T08:46:08.59+00:00

What operations to the RAM or what APIs do you use in your win32 application?
Viorel 122.6K Reputation points

2021-01-05T09:03:21.503+00:00

Maybe you should consider INVD and WBINVD instructions in case of corresponding microprocessors or check the technical documentation about preventing caching.